[0001] This invention relates to latch arrangements for closures such as automotive doors
and tailgate locks, and is particularly, although not exclusively, useful with electronic
central locking systems for vehicles.
[0002] Electronic central locking systems are well known, and a typical such system is disclosed
for example in
GB-A-2167482; an improvement is disclosed in our
PCT publication WO97/28338. These systems provide central control of the locking and unlocking of vehicle doors
and other closures such as tailgates, bonnets and petrol caps, amongst other vehicle
functions such as lights. They interact mechanically with the conventional locking
mechanisms which usually comprise, for each door, an external key mechanism and an
internal door locking knob. Interior and exterior door handles are rendered inoperable
or neutral by such locking mechanisms.
[0003] Vehicle door latches are disclosed for example in our own
applications WO97/19242 entitled "Latch and Latch Actuator Arrangements",
WO97/19243 entitled "Latch Arrangement suitable for an Automobile Door" and
WO97/28337 entitled "Latch Actuator Arrangement". An electric motor incorporated within the
latch, and usually controlled by the central locking arrangement, drives a mechanism
for unlocking and locking the latch. A problem with door latches manufactured in accordance
with other patent publications, such as
EP-A-397966 (Roltra-Morese Spa) and
GB-A-2221719 (Kiekert GmbH & Co Kommanditgesellschaft) has been size, weight and complexity.
[0004] Further, whilst mechanisms for using an electric motor to complete the closure of
a partially-closed door are known as such, for example from
US-A-5423582 (Kiekert GmbH & Co Kommanditgesellschaft), and systems for using an electric motor
to release the latch and allow the door to open are also known, for example from
EP-A-625625 (General Motors Corporation) which discloses power-assisted door opening and closing,
none of these prior systems has been hitherto capable of integration with electronic
central locking.
[0005] To illustrate the possible saving in the number of latch components required to be
assembled in manufacture, it can be seen for example from
EP-A-743413 (Rockwell Light Vehicle Systems (UK) Limited) entitled "Vehicle Door Latch Assembly"
that a very large number of components is typically required in a vehicle door latch.
The present embodiments reduce significantly the number of components, by simplifying
the mechanical operation of the latch and its interaction with electric motor drive.
[0006] It is an important security feature that all electrically-operated drive systems,
such as locking and door opening or closing, can be overridden by corresponding manual
mechanical drive, as appropriate, in case of electrical malfunction or jamming.
[0007] Existing door latches for vehicles generally include components within a housing,
and components extending outside the housing which make the arrangement bulky. As
shown for example in Kiekert
US Patent No. 5419597, the levers which cause the latch to release and the door to open, and which are
connected to door handles by cables, generally project from the latch housing. We
have discovered that it is possible to simplify the latch arrangement and to accommodate
door handle-operated levers inside the latch housing, by providing a common axis of
rotation for the latching pawl (sometimes denoted by the general term "locking member"),
the pawl release lever connected to the door handle, and preferably also a rotary
coupling member for selectively coupling the pawl release lever to the pawl.
[0008] Door latches typically comprise housings to which components are permanently riveted,
so that the door latch cannot be disassembled non-destructively.
[0009] In some door latch arrangements incorporating electrically-powered actuation members
for locking and unlocking, locking and unlocking is temporarily blocked if one of
the door handles is pulled, but is unblocked once the handle is released. It then
becomes necessary to repeat the actuation for locking or unlocking. In order to overcome
this problem, an embodiment enables such actuation to be continued fully to completion
once the handle has been released, without the need to repeat the actuation.
[0010] Automotive key mechanisms typically provide a rotational output drive, for example
through a spindle on the axis of rotation, or a radial arm connected to the spindle.
In order to make latch assemblies more compact and simple, we have found that it is
desirable to convert such rotary motion to a linear motion for the driving of the
appropriate linear actuator within the latch arrangement, for locking and unlocking.
[0011] In order to couple electric motor drive to various appropriate actuation members
within the latch assembly, for door opening and/or closing and/or for locking and
unlocking or other functions such as child-safety locking, we have discovered that
a rotary indexing mechanism is particularly useful, in which there is resilient coupling
between formations in the driving actuators and formations on the rotary indexing
mechanism. The resilience of this coupling allows the continued rotation of the indexing
mechanism past the actuator once actuation has been completed over a phase of rotation
of the indexing mechanism, and prevents jamming. It also simplifies the mechanical
arrangement, by allowing positional tolerance.
[0012] Electric door opening, i.e electrically-driven release of the latching mechanism
enable the door to open. Selective coupling of interior or exterior door handles,
for example, to the door opening mechanism of the latch arrangement, under the control
of a common electric motor are described. This is particularly advantageous as it
provides electric control independently of each door handle, and thereby avoids the
need to use a mechanical control for child-safety locking. .
[0013] Some existing door latch arrangements provide for so-called panic door opening, by
which the door can be unlocked by the operation of the interior door handle without
the need to lift the interior door knob. The door then remains unlocked to ensure
that the door can be opened by the exterior door handle. This prevents inadvertent
locking out of the vehicle by the occupant. Usually, the door latch will be unlocked
when the vehicle is in motion, but there may be circumstances in which it is locked
with the vehicle stationary or even moving.
[0014] A particularly important invention is the combination of electric locking and electric
door latch release (door opening) using a common electric motor. This provided by
the invention as defined in claim 1.
[0015] Latch arrangements typically comprise a latch bolt, for engaging a fixed striker
in the door frame, and a latching pawl for releasably holding the latch bolt so as
to latch the bolt. Electric door opening can then be achieved by actuating the latching
pawl. We have discovered a particularly beneficial arrangement for electrical door
latch release and door opening, using a linear actuator acting directly on the latch
pawl, this arrangement allowing independent door opening by external mechanical means
such as the door handle.
[0016] An alternative beneficial arrangement for electrical door latch release on manual
door opening, using a rotary actuator acting directly on the latch pawl, is defined
in another embodiment.
[0017] Electrically-powered door closing requires application of the drive to the latch
bolt which then pulls on the fixed striker to draw the door to its fully closed position.
We have found that a particularly beneficial arrangement is to have a rotary actuator,
under electric power, acting on the latch bolt. Preferably, the arrangement also provides
door opening, i.e. the same electrical drive, and preferably the same rotary actuator,
is used to release the latch pawl to allow the door to open.
[0018] As a beneficial alternative to the arrangement using a rotary actuator, also provides
a linear actuator acting directly on the latch bolt, again with optional door opening.
[0019] With all of these arrangements, there is preferably a full mechanical override of
any electrical function, i.e. mechanical actuation is independent.
[0020] As mentioned above, cables, typically Bowden cables, are used to link the latching
arrangement with door handles and key mechanisms and the like. Conventional means
for coupling cable ends to actuator arms comprise special formations on the arms for
engaging a cylindrical nipple at the end of the cable. We have found that it is not
necessary to provide specially-moulded actuator arms for retaining cable nipples,
and an embodiment enables the use of a simple planar blank to form the appropriate
actuator arm. A flange at the end of the blank is folded over to define an appropriate
formation for receiving and retaining the nipple whilst still allowing it to rotate
freely.
[0021] In order that this may be better understood, the preferred embodiments thereof will
now be described, by way of example only, with reference to the accompanying drawings,
in which common reference numerals are intended to denote identical or equivalent
parts throughout, Fig. 39 to Figure 50 relate to embodiments not covered by the claimed
invention.
Figure 1 is a schematic diagram of a car with central locking;
Figure 2 is a schematic diagram of a car door and part of the frame;
Figure 3 is a schematic block diagram of a central locking system and of one of the
latch arrangements;
Figure 4 corresponds to Figure 1 of our PCT Application No. WO97/28338 mentioned above, and is a schematic wiring diagram of an electronic central locking
system for a motor vehicle;
Figure 5 is a view from one side of a mechanically-driven switch arrangement forming
part of a latch arrangement for a car door;
Figure 6 is a schematic plan view of a cam assembly forming part of the arrangement
of Figure 5;
Figure 7 is a schematic circuit diagram of the motor control circuit including the
switches shown in Figure 5;
Figure 8 is a schematic circuit diagram corresponding to Figure 7, but additionally
including a relay switch for door opening control;
Figure 9 shows an electric door opening mechanism;
Figure 10 shows an alternative electrical door opening mechanism;
Figure 11 shows an electrical door opening and closing mechanism;
Figure 12 shows an electrical door opening and closing mechanism;
Figure 13 shows a further electrical door opening and closing mechanism;
Figure 14 shows a variant of the electrical door opening and closing mechanism of
Figure 13;
Figure 15 shows an electrical door opening mechanism, as a variant of Figure 10;
Figure 16 shows an electrical door opening and closing arrangement as a variant of
Figure 13;
Figure 17 shows a further electrical door opening and closing mechanism;
Figure 18 shows a further electrical door opening and closing mechanism, using a rotary
indexing and driving mechanism;
Figure 18a shows a door opening arrangement integrated with electrical locking;
Figure 18b shows an electrical door opening and closing mechanism, using a bi-directional
rotary driving and indexing arrangement;
Figure 19 shows a latch arrangement with a rotary driving and indexing mechanism for
electrical door opening and closing, also enabling powered door opening;
Figure 20 is a partial view of two of the components of Figure 19;
Figure 21 is a simplified view of two of the components of Figure 19, but in which
the motor gearing is modified;
Figure 22 shows an electrical door opening and closing mechanism, as a variant of
Figure 16;
Figure 23 shows a further door opening arrangement;
Figure 24 shows a compact latch arrangement within a housing suitable for vehicle
doors, with electric locking;
Figure 25 shows a latch arrangement for the selective electrical locking of a door
with two door handle mechanisms and an interior door knob;
Figure 26 shows a variation of the latch arrangement of Figure 25;
Figure 26A is a schematic partial enlarged end view from the right of the arrangement
of Figure 26;
Figure 27 shows a door handle lever of the type shown in Figures 25 and 26 and illustrates
how the actuation of the mechanism towards its unlocked, handling-coupling position
is continued automatically even after it has been blocked temporarily by the door
handle being actuated;
Figure 28 illustrates an alternative form of rotary coupling member for the arrangements
shown in Figures 25 and 26;
Figure 29 illustrates the use of an electric motor for actuating a child-safety arrangement,
in a latch arrangement of the type shown in Figures 25 and 26;
Figure 30 shows an integrated electrical door opening and closing, and central locking
arrangement, using a common electrical motor,
Figure 31 shows the use of a rotary indexing and driving mechanism for three separate
actuation functions in a latching arrangement;
Figure 32 shows a variation of the arrangement of Figure 31, for four independent
actuation mechanisms;
Figure 33 shows the use of a rotary indexing and driving mechanism for the independent
actuation of locking and door opening, suitable specially for use with a tailgate
or boot latch;
Figure 34 shows the use of a rotary indexing and driving mechanism for driving two
linear actuators selectively, for example those shown in Figures 25 and 26;
Figure 35 illustrates a possible form of resilient coupling between an actuation member
and a rotary drive member, useful for example in the arrangement of Figure 25;
Figure 36 shows an alternative form of resilient coupling between a rotary drive member
and an actuation member;
Figure 37 shows an alternative resilient coupling arrangement suitable for use in
the arrangement of Figure 36;
Figure 38 shows an alternative form of selective coupling between two actuators and
a rotary indexing and driving mechanism;
Figure 39 shows schematically a disc for converting the rotary movement of a key mechanism
into the linear movement of two independent actuators so that the actuators move in
opposite directions and reciprocate;
Figure 40 shows an alternative to the disc of Figure 39, in which the actuators are
made to reciprocate together in the same direction;
Figure 41 is a side view of the disc of Figure 39 also showing the ends of the actuators;
and
Figure 42 is a view corresponding to Figure 41 for the disc of Figure 40;
Figure 43 shows part of a key mechanism having a rotary output drive disc of the type
shown in Figures 39-42;
Figure 44 shows schematically a rotary output spindle of a cylinder key mechanism,
with a radial arm;
Figure 44a shows one form of coupling between the rotary output of the key mechanism
of Figure 44 to a pair of linear actuators, for reciprocating motion in the same direction;
Figure 44b shows an arrangement corresponding to Figure 44a, but in which the linear
actuators move in opposite directions;
Figure 44c shows an alternative form of rotary output drive of a key mechanism and
a rotary to linear converter arrangement for driving a linear actuator;
Figure 45 shows a double locking arrangement for a key mechanism and an interior door
knob, suitable for use with any of the latch arrangements described in relation to
the other drawings, for example Figures 25 and 26;
Figure 46 illustrates an actuation plate formed from a planar blank with an end arrangement
for connecting to a cable, and a method of formation of such an arrangement;
Figure 47 shows part of a latch arrangement of the type shown in the other drawings,
with a single housing which is disassemblable non-destructively;
Figure 48 shows how a single key mechanism can be arranged to operate two separate
locks in different parts of a vehicle;
Figure 49 illustrates a clutch mechanism for the electrical drive for example to a
door opening and closing mechanism;
and Figure 50 is a perspective view of a clutch-actuating lever of the clutch mechanism
shown in Figure 49.
Motor Vehicle with Central Locking
[0022] Figures 1 and 2 illustrate a conventional arrangement for locking vehicle doors and
other closures. Latches L1 to L4 are bolted on to each of the four passenger doors,
latch L5 on to the tailgate (boot) and latch L6 to the petrol locking cap. The vehicle
battery is connected to a central electronic control system 90 which in turn is connected
by electric cabling (not shown) to the latches.
[0023] As shown in Figure 2, each door has interior and exterior handles, a key mechanism,
usually in the form of a cylindrical key mechanism, and an interior door knob which
is constrained to move linearly between an unlocked position, at which the knob projects
from the door frame, and a locked position, at which it projects only slightly from
the door frame. A striker, in the form of a cylindrical bar, is fixed vertically in
the door frame. The door latch arrangement L1 is bolted to the door such that a latch
bolt, described in more detail below, engages the striker to hold the door in its
closed position. A door has a resiliently-deformable seal (not shown) which is deformed
as the door closes against the frame, and which causes the door to open as soon as
the striker is released by the latch bolt. However, even in the absence of such a
seal, the latch bolt is normally spring biased to the open position so that it opens
the door.
[0024] The function of the latch L1 is described in greater detail with reference to Figure
3, which also shows the central electronic control unit 90 and car battery to which
it is connected by an electric cable. The striker 10 is also shown, partially surrounded
by the jaw of the latch bolt 11. A latching pawl 20 engages an edge of the latch bolt
in order selectively to latch it fully or to half-latch it, in a conventional manner.
The pawl is rotated under the control of various coupling members which are linked
respectively to the exterior and interior handles, interior door knob (where provided)
and mechanical child-safety lock control (where provided). An electric motor 70 is
controlled by the central electronic control unit 90 in accordance with the rotary
position of the latch bolt 11, which is sensed, as described below with reference
to Figures 5 to 8, by position sensors and switches within the latch L1.
[0025] This position sensing provides the necessary information for the control of most
electrical functions connected with door locking, closing and opening, and, although
not always specified in the following description, it is included in most latch arrangements.
[0026] The electric motor is controlled to operate the pawl to release the latch bolt, for
electrical door opening. It is also controlled to selectively couple the exterior
handles and knobs to operate the pawl appropriately. However, in some arrangements,
separate electric motors may be provided for this purpose, depending on design requirements
and space availability.
[0027] The central electronic control circuit 90 is shown in Figure 4, together with the
electric motors shown as A for the four doors and the tailgate and filler (petrol)
cap catch; also for the engine compartment catch (bonnet catch). In this example,
the interior lock is operated simply by an electric switch R6, avoiding the need for
an interior door knob, although such a knob could also be provided. The function of
this circuit need not be described in detail here, but is described more fully in
WO97/28338, referred to above.
[0028] The electrical control system will now be described with reference to Figures 5 to
8. In accordance with the invention, there is mechanical position-sensing using microswitches,
which alternates the polarity of the electricity supply to the motor, corresponding
to the reciprocating motion of the body being driven by the motor, in this case the
latch bolt 11. This mechanically-responsive power supply can also be operated together
with electronic control through a relay switch, for initiating door opening, as will
be described below with reference to Figure 8.
[0029] As shown in Figure 5, a camming member 101 is arranged for pivotal motion about the
same axis 15 as the latch bolt 11, and it is driven by means of a projection 140 engaging
in a recess 141 in the latch bolt 11. As also shown in Figure 5, the latch housing
100 has three parallel layers, and these three layers are rigidly interconnected by
means of a hinge on the axis 15, serving both the camming member 101 and the latch
bolt 11. The camming member 101 is capable of sliding upwards and downwards on its
pivot axis, to allow cam-following microswitch actuators 111,121 and 131 to follow
rectangular cam tracks C, B, A respectively shown in Figure 6. The camming member
101 is biased by a spiral spring 19, upwards in Figure 5, and downwards, shown by
arrow 191, in Figure 6. A bank of three microswitches 110, 120, 130 is connected rigidly
to the latch housing 100, so that the corresponding microswitch actuators ride along
their respective rectangular cam tracks.
[0030] The face of the camming member 101 which faces the bank of microswitches is shown,
to an enlarged scale, in Figure 6. Unshaded portions of each cam track are the deepest,
as represented by line 102 in Figure 4; heavily shaded areas in Figure 6 represent
a shallow floor to the cam track, as represented by line 103 in Figure 5. Ramps from
the deeper to the shallower areas are shown by shading of an intermediate density
in Figure 6. The respective rectangular cam tracks are defined by rectangular walls
as shown, and by central walls 104, 105 and 106. The pin-shaped microswitch actuators
111,121, and 131 are represented as circles in Figure 6, at position indicative of
their motion along the respective cam tracks. When the door is open, the microswitch
actuators are at the top right hand comers of the cam tracks shown in Figure 6. As
the door begins to close, their relative positions move in the direction shown by
Letter L, to the positions shown as A, B, C in Figure 6. At this point, the door is
fully closed.
[0031] A formation H, extending diagonally across the middle cam track B, and continuous
with the end face of the middle wall 105, cams the entire cam assembly 101 upwards
in Figure 6, against the spring bias, in the direction M, as the latch bolt 11 moves
towards the door open position. This is because of the sliding camming action of pin
121 on step H. Continued motion in the direction K brings the microswitch actuators
back to position F, at which point the spring force 191 returns them to the top right
hand comer as shown in Figure 6, with the cam assembly moving in direction N. The
ramps E cause the cam actuators to be depressed into the respective microswitches,
to change the microswitches from "off" to "on". Abrupt steps H allow the microswitch
actuators to spring out again, turning the microswitches off.
[0032] The motor control will now be described with reference to Figures 7 and 8, which
show alternative arrangements of the circuitry. In a motor vehicle, each door is controlled
by its own motor 70, and each door has a red hazard light 80 to warn motorists that
the door is open. The vehicle has a central electronic control circuit 90, with integrated
stall current sensor circuitry 91, of a conventional type. First microswitch 110 controls
the switching of the door hazard light 80. Second microswitch 120 provides power of
one polarity to the motor, appropriate for door closing control. Third microswitch
130 supplies power at the opposite polarity to the motor, appropriate for door opening
control. The mechanical arrangement of Figures 5 and 6 ensures correct sequencing
of these microswitches. Using conventional notation, NO represents the normally open
terminal, NC represents the normally closed terminal, and C represents the common
terminal. With the door closed, the microswitch actuators are at positions A, B and
C in Figure 6, and all microswitches are off. Movement towards the opening position
causes motion of the microswitch actuators in the arrow K of Figure 6, and after a
small neutral movement, microswitch 130 is switched on, as actuator 131 rides up the
ramp E. This provides power assisted door opening. Whilst the door is being opened,
the door hazard light control microswitch comes on, as actuator 111 rides up its own
ramp. When the door has reached the end of the power assisted motion, the door opening
microswitch 130 is switched off, and only the door hazard light remains on. As the
door is reclosed, the door closing control microswitch is immediately switched on,
as the actuator 121 rides up its ramp from line F of Figure 6. During door closure,
the hazard light is switched off.
[0033] When fully closed, the door closing control microswitch 120 switches off, as actuator
121 drops down the step at line G in Figure 6.
[0034] It is preferred that door opening be initiated under central electronic control,
and this is provided by the relay switch 140 of Figure 8. A signal from the central
electronic control circuitry 90, along lines 150, switches on the relay 140 to power
the motor, and remains on for a sufficient period to move the mechanical arrangement
to the point at which the third microswitch 130 switches on. The relay switch will
then switch off, or time out.
[0035] The stall current sensor circuitry 91 need not be described in detail. In this example,
it is a circuit breaker which provides over current protection, and is manually re-settable
when tripped. current sensing of the drive motor current takes place in its ground
return path, and current sensing is effected by means of a resistor, whose voltage
is amplified by an appropriate integrated differential amplifier. A second amplifier
determines the voltage difference between the resistance value and the value of a
reference voltage, provided by a temperature stable diode. The second differential
amplifier acts as a comparator, providing logic level conversion, and outputting a
stall signal.
[0036] Remote control transmitters are conventionally provided to control the central locking
system, for example to unlock or lock the car from outside. The same command can be
used by the central control system to open the doors, or specific doors, by remote
control. However, the same type of remote control may be adapted, in accordance with
one of the inventions, to operate electrical child-safety locking.
[0037] The central electronic control circuitry preferably received inputs from sensors,
some of which are placed inside the latch to determine the positions of pawl, the
latch bolt, and pawl actuator, or any other part of the latch mechanism. Some other
sensors are preferably placed elsewhere in the vehicle, for example to monitor the
state of the car engine. For example, the current energising the drive motor can be
cut off, by the central electronic control circuitry 90, when the engine has been
started and the car is in motion. This safe guards against accidental electrical door
opening. As a further example, if the door is jammed and the motor drive is stalled,
the current sensor circuitry 91 sends a message to the central electronic control
circuitry 90 which cuts the current energising the motor until it detects certain
predetermined favourable conditions, for example the release of the door handle and
the moving of the door to a certain position manually.
[0038] The specific arrangements described above in the context of a motor vehicle provide
significant cost benefits. By incorporating the switches in the latch housing, this
minimises the length of wiring, and in fact it is possible to reduce the necessary
wiring to just the two wires shown in Figure 7, or the four wires 150, 151 and 152
shown in Figure 8, linking the door latch with the central control. By integrating
the door hazard light with the door latch, for example by having a simple plug-in
lamp, this minimises wiring and assembly costs. The integrated arrangement of the
door opening and door closing microswitches, arranged in the same bank, is the most
efficient arrangement, and minimises wiring.
Electrical Door Opening and/or Closing
[0039] The operation of the latch bolt and pawl in relation to the movement of the door
is described below with reference to Figures 19 to 21, and also in the published patent
specifications referred to above.
[0040] As shown in Figure 9, a latch bolt 11, closable around a striker 10, has notches
13 and 14 respectively for full-latch and half-latch detention of the pawl 20. The
latch bolt 11 is spring biased clockwise to the open position, and the pawl 20 is
spring biased anti-clockwise (B5) to the latching position at which the latch bolt
is latched. An electric motor 70 has a rotary output with crown and bevel gearing
to a rotary output drive 50 which is arranged to rotate in the direction D1 so that
its eccentrically-located projecting pin 30 abuts against the pawl 20 to move it in
direction D2 to its unlatching position. Upon continued rotation in direction D1,
the pin 30 allows the pawl 20 to spring back in direction D5, to latch the latch bolt
once again after the door has been closed.
[0041] The pin 30 is returned to its original neutral position Np, as shown in Figure 9,
either by the force of the pawl 20 returning to its latching position, or else under
the reverse drive of the electric motor 70. It is then ready, in its neutral position,
for a further door-opening actuation.
[0042] Obviously alternative output drive couplings are possible, for example screw gears
or spur gears. Further, the pin 30 could be replaced with any form of cam arrangement
for abutting against a pawl.
[0043] In this arrangement, the door is opened, once the pawl has moved to its unlatching
position, under the force of the resiliently-deformed door seal. The spring bias of
the latch bolt 11 also contributes to the opening of the door.
[0044] An alternative form of door opening arrangement is shown in Figure 10. The electric
motor 70 output drive takes the form of a rack and pinion arrangement 31 producing
linear drive in the direction D1, with part of the rack abutting against the pawl
20. Once the latch bolt has been electrically sensed to have moved to its fully unlatched
position, the electric motor is either switched off, or else powered in the reverse
direction, to bring the rack 31 back to its neutral position as shown in Figure 10.
When it is switched off, the rack remains in its door-opening position until the door
is shut. Shutting the door causes the pawl to rotate to its latch engaging position,
simultaneously driving the rack back to its neutral position. This is assisted by
the spring biasing of the pawl 20.
[0045] The sensing of the position of the latch bolt also of course applies to the arrangement
of Figure 9, for either switching off or reverse powering of the electric motor.
[0046] The arrangements of Figures 9 and 10 are suitable for vehicle side doors. Tailgate
and boot latch bolts differ from that illustrated, in that they normally only one
notch 13, for fully latching the bolt. Again, various alternative gearing arrangements
would of course be possible.
[0047] The latch arrangement shown in Figure 11 provides for powered door closing as well
as electric door opening. Thus it is an opening and closing mechanism, powered by
the same electric motor 70. The electric motor drives a rotary indexing and driving
member 50 selectively in either direction, D1 or D4. Its neutral position Np, shown
in Figure 11, corresponds to the position at which its pin 34 is free of the door
latch 11. The indexing and driving member 50 is rotationally biased towards its neutral
position by a torsion spring 36 mounted co-axially with the member 50, and constrained
by a bar 35 fixed to the latch housing. The torsion spring 36 has two limbs 33a and
33b which engage opposite side surfaces of the projecting pin 34. Thus as the member
50 is driven clockwise in direction D1, pin 34 drives limb 33a of the spring which
then causes the member 50 to return in the opposite direction to the neutral position.
Correspondingly, anti-clockwise movement D4 causes pin 34 to displace limb 33b of
the spring, which again returns the member 50.
[0048] In this example, the unlatching or release of the pawl 20 is achieved indirectly
through an actuation plate 38 pivotally connected at 40 to the pawl 20, and coupled
to the rotary indexing and driving mechanism 50 by means of an arcuate slot 39 and
a projecting pin 32 of the member 50. The arcuate slot 39 of the actuation plate 38
is cocentric with the rotary member 50, and its function is to allow relative rotation
of the rotary member 50 for approximately 70° in the clockwise direction D1, for door
closing, without interference.
[0049] An extension arm 37 of the latch bolt 11 projects over the rotary indexing and driving
member 50 for selective engagement with the pin 34. To close the door, the pin 34
is driven clockwise in direction D1 to the position A which the latch bolt 11 will
have reached as a result of partial closure of the door manually. Completion of door
closing is achieved by pin 34 abutting against extension 37 and driving it in the
direction D3 to its fully latched position B. Once the latch bolt is electrically
sensed to be fully latched, the motor is switched off and the rotary member 50 is
returned by the spring 36 to its neutral position Np.
[0050] To open the door electrically, the motor drives the pin 34 anti-clockwise in direction
D4, causing the pin 32 immediately to pull the end of the slot 39, thus to pull the
pawl 20 in the direction D5 to unlatch it in direction D6. The latch bolt then springs
open in the direction D7 as the door moves away from the frame in direction D8. Once
the latch bolt has electrically been sensed to have reached its fully unlatched position,
the motor is switched off, and rotary member 50 springs back to its neutral position
Np.
[0051] The electrical position sensors are placed suitably in the latch so that, for example,
when the pawl 20 is actuated to its unlatching position, it is prevented from falling
into its half-latched position in notch 14.
[0052] This arrangement is capable of being accommodated in a single housing which is compact
and simple to produce, improving on sound proofing and reducing manufacturing costs.
[0053] The latch arrangement of Figure 12 is a variant of that of Figure 11, for door opening
and closing. In this example, the actuator plate 41, which replaces plate 38, is arranged
to slide over the pivot axis 43 of the rotary indexing and driving member 50; it has
a slot 45 which guides it over the pivot 43. The actuation plate 41 has an end flange
44A depending downwardly for abutting engagement with the pin 34 of the rotary member
50. The actuator plate 41 is capable of sliding between positions C and C1, corresponding
to the latched and unlatched positions respectively of the pawl 20.
[0054] Door closing is caused by rotating the pin 34 clockwise in direction D3 to abut against
the latch bolt extension 37 at A and drive it to position A1. After a slight overtravel
beyond point A1, the cam pin 34 becomes free from the latch bolt whilst rotating in
the direction D3 towards a second neutral position Np2. Thus the first neutral position
Np1 is located just before the cam pin 34 engages the latch bolt extension 37. The
second neutral position Np2 is located at a point just past A1 but before it can engage
the flange 44A. Once freed from the latch bolt, the cam pin 34 stops at its second
neutral position Np2, by a resiliently deformable means such as a spring (not shown),
after the motor has been switched off under the control of a suitable electrical position
sensor (not shown). The motor may also be stopped at the second neutral position by
means of a controlled powering of the motor in the reverse direction.
[0055] To open the door electrically the motor is powered to drive the cam pin from its
neutral position 34B in direction D3 to the point 34C at which it abuts the actuator
plate 41 to the point C1 at which the flange reaches the position 44B in direction
D7. This causes the pawl to rotate in direction D4 to its fully unlatched position
which allows the latch bolt to rotate in direction D5 whilst simultaneously moving
away from the striker in direction D6. The cam pin 34 continues in the same direction
to its first neutral point Np1.
[0056] At either neutral position, the latch bolt and pawl are completely free to be actuated
manually, in a conventional manner, between their latched and unlatched positions.
Thus conventional mechanical operation is interrupted only during electrical door
opening and closing. This provides complete mechanical override as a safety measure
against electrical dysfunction.
[0057] In contrast to the arrangement of Figure 11, the rotary indexing and driving member
50 rotates uni-directionally, although its motion may be braked or partially reversed
by reversed electrical drive.
[0058] The arrangement of Figure 12 has the advantages of compactness and sound proofing
associated with the arrangement of Figure 11.
[0059] A variant is shown in Figure 13, providing electrical door opening and closing using
the same electrical drive motor 70. In this example, the rotary output drive at 50
is converted to linear motion by a rack and pinion gear. The rack 56 is formed integrally
with a shuttle which has an end abutment surface 55 for engaging the latch bolt extension
37. At the other end, the rack is connected at 57 to a coil spring 58 mounted on the
frame 59 of the latch housing, for compression and tension. The spring serves to return
the shuttle to a neutral position Np and also to absorb shock and reduce noise.
[0060] The shuttle 56 is connected drivingly to an actuator plate 52 by a pin 54 riding
in a slot 53, such that the shuttle is capable of driving the latch bolt for door
closing without interference. The actuator plate 52 is pivotally connected at 51 to
the pawl 20.
[0061] As with the arrangements of Figures 11 and 12, the electric drive mechanism is isolated
from the conventional mechanical latch operation, by which a door handle operates
the pawl, when it is at its neutral position Np.
[0062] Thus to open the door the shuttle 56 is driven from its neutral position to its extreme
position P1 in direction D3, after which the electric motor is switched off and it
returns to its neutral position. Electrical door opening is achieved by driving the
shuttle in the opposite direction D5, from the neutral position to the second extreme
position P2, which pulls the actuation plate 52 and releases the pawl.
[0063] This arrangement uses a potentially smaller drive motor, due to the greater gearing
ratio.
[0064] A further modification of the door opening and closing mechanism is shown in Figure
14. Instead of the rack and pinion arrangement, a linear shuttle 71 is driven in either
linear direction by the cam pin 34 of the rotary indexing and driving member 50, in
direction D1 or D2 as the case may be. The cam pin 34 rides against a cam 74 fixed
to the shuttle 71, so that drive is effected over a limited angular range or phase,
for example about 40°, of rotation of the rotary member 50. Once again, the shuttle
71 is biased towards its neutral position by a tension-compression spring 72 mounted
to a frame 73. The shuttle has an end formation 78 which drivingly abuts against the
latch bolt extension 37 to move it from position A to position B. For electrical door
opening, an actuator plate 77 corresponding to plate 52 is provided to link the shuttle
71 with the pawl 20. As with the arrangement of Figure 13, a pin 75 on the shuttle
slides within a groove 76 of the actuator plate 77.
[0065] The arrangement of Figure 14 has the additional advantage of adaptability, and it
provides for an easier movement of the drive gear to its neutral position in the event
that electrical actuation is prematurely interrupted.
[0066] An alternative arrangement for electrical door opening is shown in Figure 15. In
this example, the shuttle 83, which is again constrained to move linearly, is driven
from the electric motor 70 by means of leadscrew gearing taking the form of screw
81 and internally-threaded nut 82. The leadscrew 81 is driven by bevel gearing 80
from the rotary output drive. Once again, the shuttle is spring biased to its neutral
position by a tension-compression spring 86. The slot 84 which couples to the pin
85 of the pawl 20 gives sufficient freedom to allow for independent mechanical door
opening, as before. In this example, there is no provision for door closing, although
of course this arrangement could be incorporated in the door closing arrangements
of Figures 12 and 13 for example. The arrangement is simplified, and provides for
just one neutral position A and one actuated position B of the shuttle 83.
[0067] This arrangement has the further advantage of complete independence of the mechanical
door opening and closing from the electrical arrangement, at all stages of electrical
door opening. It also has the advantages of enabling use with a relatively small motor,
due to the high gearing ratio, and is extremely adaptable and simple. As before, the
compression-tension spring provides an anti-backlash arrangement which reduces noise
by absorbing the inertia of the mechanism after the motor has been switched off; this
also prolongs the life of the drive mechanism.
[0068] A further variation of the door opening and closing mechanism is shown in Figure
16. The shuttle 95 in this example is driven linearly by a leadscrew 96 between two
spaced tension springs 97 and 98 which are mounted on the leadscrew 96 between fixed
brackets 99 and 200. The leadscrew is driven by a bevel gear 80 powered by the motor
70. The actuator plate 91 is again coupled to the shuttle 95 by a pin 92 sliding in
a slot 94, and the shuttle 95 has an abutment surface at its end 93A which moves between
a neutral position 93B, position A, a lower position 93C, position C, at which the
pawl is unlatched, and an upper extreme position 93A, position B, at which the latch
bolt is completely closed.
[0069] Preferably, the nut 95, formed integrally with the shuttle, and the screw 96, have
their meshing teeth cut at 45° in relation to the axis of rotation of the leadscrew
96, so that the shuttle can drive the leadscrew and vice-versa. The means for constraining
the nut 95 to move linearly may take any suitable form, such as grooves and rails
(not shown) fixed to, or integral with, the latch housing (not shown).
[0070] The springs 97, 98 may be replaced by a single spring capable of use as a compression
or tension spring coupled to the nut 95. It may also be a torsion spring coupled to
the drive gear.
[0071] As with previous arrangements, electrical position sensing is employed to control
the powering of the electric motor. A current sensor may be incorporated with the
control electronics as an indicator that the latch bolt, for example has reached its
latching position, since only overtravel beyond that point raises the current. Again,
polarity of the electrical drive may temporarily be reversed, to counteract the inertia
of the moving components.
[0072] This arrangement has advantages corresponding to the advantages of the arrangements
of Figures 14 and 15.
[0073] With any of the arrangements of Figures 9 to 16, a clutch mechanism may be provided
in the rotary output drive of the electric motor 70. A conventional centrifugal clutch
is preferred. This would eliminate any inductive current generated in the motor when
it is driven by the mechanical components. It also helps to reduce the load on the
return springs which are used for bringing the mechanism back to its neutral position
after motorised actuation.
[0074] A further modification of the previously-described electrical door opening and closing
latch arrangements is shown in Figure 17. In this example, the actuator plate 202
is connected pivotally at 203 to the pawl 20 near to the point of engagement with
the latch bolt 11. It therefore operates in the reverse direction, as there is no
lever action. This actuator plate 202 is constrained to rotate about the pivot axis
of the rotary indexing and driving mechanism 50, or to move linearly in the actuation
direction D4, by virtue of an end fork with limbs 205 and 206 on either side of the
pivot axis.
[0075] In this example, the cam pin 34 is replaced by an arrangement of radial cams all
integral with the rotary mechanism 50 and arranged in two separate planes normal to
the pivot axis. In a first plane, radial cam 207 is arranged selectively to abut and
drive the latch bolt extension 37. In a separate plane, radial cams 209 and 208, spaced
by approximately by 100°, respectively engage a depending lug 204 of the actuation
plate 202 of the door opening, and a W-shaped leaf spring 210 fixed to the latch housing.
The W-shaped spring 210 is a shock-absorber for the cam 208 as it rides up either
limb, and locates it centrally. The spring 210 prevents backlash as well as locating
the arrangement in its neutral position as shown.
[0076] To close the door, the rotary member 50 is driven clockwise in direction D1 to drive
cam 207 against the latch bolt extension 37, as previously described. To open the
door electrically, the rotary member 50 is also driven in direction D1 from its neutral
position, to engage the lug 204 to drive the actuator plate 202 in direction D4 to
unlatch the pawl.
[0077] Should electrical actuation be interrupted for whatever reason, the drive gear is
moved back to its neutral position by means of a sliding spring (not shown) coupled
to the drive gear. This guarantees full mechanical override, in the case of electrical
malfunction.
[0078] The latch arrangement of Figure 18 importantly illustrates the use of one electric
motor 70, and one rotary indexing and driving mechanism 50, to control independently
the door opening and closing mechanism on the one hand, and electric locking, on the
other hand. The door opening and closing mechanism involves a shuttle 215 constrained
to move linearly, and coupled to a tension-compression spring 218, as previously described
in relation to Figure 14. The rotary member 50 has a single cam pin 34 which is rotatable
in either direction D1, D5 between two neutral positions Np1 and Np2, at which it
is retained respectively by W-shaped fixed springs 220 and 219. An actuation member
222 is constrained to move linearly in either direction D11, D12 between positions
C1 and C2, and it has the toggle lever 221 at its end for engagement with the cam
pin 34. The toggle lever 221 may be of the type illustrated and described below with
reference to Figure 35. It is mounted pivotally at the end of the actuation member
222 and biased by a torsion spring 223 to its neutral position normal to the length
of the actuation member. This arrangement enables the cam pin 34 to abut drivingly
against the toggle 221 to drive the actuation member 222 in direction D11, but then
to release it as it is resiliently deformed against the spring torsion, to enable
the cam pin 34 to continue its rotary movement. In this example, it is capable of
being driven in either direction by the cam pin 34.
[0079] As with W-shaped spring 210 of Figure 17, the springs 219, 220 have the function
of absorbing rotary impact, as the pin rides up against the external limb of the spring
from either direction. The cam pin then moves on to settle between the two outer limbs
of the pin in the central recess. This prevents accidental overrunning.
[0080] Electrical door locking and unlocking, using the actuation member 222, is described
below in greater detail with reference to Figures 24, 26, 30 - 38. Briefly, it interacts
with a key mechanism and selectively unlocks or locks the pawl 20 to prevent or allow
actuation of door handles or the like being transmitted to the pawl.
[0081] A variation of the door opening mechanism of Figure 10, which also provides for electric
locking and unlocking under the control of the same electric motor 70, is shown in
Figure 18A. In this example, a rack and pinion arrangement integral with a linear
shuttle drives the pawl 20 by means of an abutment surface 231. The pawl 20 has an
extension lever 232 which is driven either by the abutment surface 231, or else by
a cable or other link to the latch locking mechanism (not shown). A tension-compression
spring 235 again biases the shuttle towards a neutral position N.
[0082] For electric locking, the notch 234 in the shuttle selectively engages with the end
1814 of a lever on 1810 pivoted at its centre 1812, and spring biased by a torsion
spring 1813 on the pivot axis 1812 towards the neutral position as shown. The opposite
limb 1811 engages in a notch of an actuation member 300 capable of moving in either
direction D7, for locking and unlocking the latch.
[0083] Figure 18B shows a further arrangement for door opening and closing, which is analogous
to the arrangement described below with reference to Figure 33. The rotary member
50 acts directly on the pawl 20, which has an extension arm 20A, and on the latch
bolt extension 37. The cam pin 30 is biased by spring 1802, located around fixed lock
1801, to its neutral position N.
[0084] Door closing is effected by driving the cam pin 30 against the extension 37 at the
position A towards B; it is then impelled back to its neutral position N by the spring.
Driving the motor in the reverse direction, the cam pin 30 moves in direction D2 to
abut against the pawl 20A to release the latch bolt. Again, the cam pin 30 can be
returned to its neutral position, either electrically or by the return spring.
[0085] The pawl 20 can alternatively be released manually by externally operable means such
as the handle through a lever 246 and cable 245.
[0086] In this example, the distal end 20A of the pawl 20 is elevated by bending so that
it can override the latch bolt extension 37.
[0087] This particular arrangement enables a reduction in the drive torque and renders it
more adaptable.
Door Opening and/or Closing under Electric Power
[0088] The arrangement of Figures 19-21 provides electric door opening by which the pawl
is first released and then the latch bolt is driven under electric power to ensure
that it opens fully. The arrangement also provides for powered door closing, as with
arrangements described above.
[0089] With reference first to Figures 19 to 21 of the drawings, a vehicle door closure
arrangement comprises a striker 10 connected to the door frame of a vehicle, and a
latch bolt 11 forming part of a latch arrangement supported on the edge of the vehicle
door. Whilst the shape of the latch bolt 11 in Figure 19 is special to the present
invention, its general function is conventional and need not be described in detail
here. The latch bolt 11 is mounted pivotally at 15 for rotary motion as shown by arrow
18, driven by the relative motion 17 of the striker 10 in a U-shaped notch 12 formed
in the latch bolt 11. The latch bolt 11 has two further notches 13, 14 formed in its
periphery, for engagement with a locking pawl. 20. Notch 13 is for locking the latch
bolt at a latching rotary position, which retains the striker 10 and maintains closed
the vehicle door. The door is capable of being opened, towards the right in Figure
1, by releasing the pawl 20 from its locking position in notch 13, allowing the striker
10 to drive the latch bolt 11 clockwise 18 under the camming action of the indentation
12, until it is no longer detained by the striker 10. However, if the locking pawl
20 is allowed to engage the further notch 14, at a so-called half latch position,
then the door can be half latched, partially open.
[0090] The locking pawl 20 is mounted pivotally at 21, and pivot points 15 and 21 are both
fixed to a latch housing (not shown). The pawl 20 has an end tooth 24 for locking
engagement in notches 13, 14. At the same end, it is formed with a pin 23 on which
there is pivotally mounted a link arm 25 which is coupled to a door handle for actuating
the pawl. Lifting the door handle causes the link arm 25 to move in the direction
shown by arrow 26, pulling the pawl 20 anticlockwise as shown by arrow 22, and moving
the pawl to its unlocking position (not shown).
[0091] In accordance with the present invention, the latch bolt 11 is coupled drivingly
to an electric drive motor 70, of the type commonly used for the central locking of
vehicle doors. This coupling arrangement, to be described in greater detail below,
also incorporates an arrangement for releasing the pawl.
[0092] The motor 70 is coupled to the latch bolt 11 through gears 40, 50, 60. Gear 40, shown
in isolation in Figure 20, meshes at 45 with teeth 16 on the latch bolt 11. It is
mounted for rotation about axis 42, which is shared by the larger-diameter gear 50,
shown in isolation in Figure 21. Gear 50 is drivingly coupled to gear 40, with 60
degrees of rotary free play, by means of a pair of slots 52, 53 in one of the plates
of gear 50, through which slots project a pair of driving pins 44, 43 connected to
gear 40. This 60° free play is important, in this embodiment, to allow for proper
sequencing of the pawl release and latch bolt drive.
[0093] Rotary motion of gear 50 in the direction shown by arrow 41 is controlled by its
direct meshing engagement with the spindle of the motor 70. In the embodiments shown
in Figure 19, this coupling is through the meshing of gear 71 on the motor spindle
and teeth 62 on crown gear 60, gear 60 being connected to a smaller-diameter gear
61 which drives teeth 54 on gear 60. In the alternative embodiment shown in Figure
21, worm gear 72 is driven directly by the motor spindle, and drives gear 50 directly.
[0094] One section of gear 50 has a U-shaped indentation 51 which cams against a limb 33
projecting from a hook 32 at the end of a pawl actuator 30. The actuator 30 is constrained
by formations on the latch housing (not shown) to reciprocate generally in the direction
shown by arrow 34 in Figure 19, so as to link mechanically with pin 23 of the pawl
20. The upper end of the pawl actuator 30 is shaped as a dog leg with an extension
formed with a slot which surrounds the pin 23. This arrangement provides free play
in the driving connection between the pawl actuator 30 and pawl 20.
[0095] The operation of the power-assisted door latch will now be described. It will be
appreciated that the door latch can be operated either mechanically, without motor
power, or else under motor power. This of course is an important safety feature.
[0096] Powered operation will be described first. With the door in its closed position,
as shown in Figure 19, the latch bolt 11 is at its latching position, and the locking
pawl 20 at its locking position. Pawl actuator 30 is engaged by the gear 50. Upon
receipt of a command to open the door, from the central electronic control circuit
90, the motor 70 drives the gear 50 anticlockwise as shown at 41. For the first 60°
of rotation, the gear 40 will remain stationary, and no attempt is made to rotate
the latch bolt 11. Otherwise, the latch and pawl would jam. The indentation 51 pushes
the pawl actuator 30 in the direction of arrow 34, and this immediately pushes against
pin 23 and drives the pawl anticlockwise as shown by arrow 22, to move it to its unlocking
position. Continued rotation of gear 50 cams out the extension 33 of the pawl actuator
30, so that it rests on the outer periphery of gear 50, and is temporarily prevented
from re-entering. Continued rotation past the first 60° causes the walls of slots
52, 53 to engage the pins 44, 43 of the smaller gear 40, which drives the latch bolt
11 in the direction shown by arrow 18. With powered operation in this way, half latching
is deliberately prevented. Thus the latch bolt is rotated so that notch 14 passes
tooth 24, and until the outer surface of latch bolt 11 engages tooth 24 the pawl 20,
preventing re-entry of the pawl.
[0097] Electronic position sensors, to be described below, cause the motor drive to switch
off at the point that the vehicle door is partially open, and has passed its unlatched
position. The door can then conveniently be opened fully by the passenger or driver.
[0098] Driving the latch bolt 11 clockwise has the desirable effect of pushing the door
open, by reacting against the striker 10. This accelerates opening movement of the
door, and such opening movement will continue until it is decelerated by friction
in the door hinges, by an amount dependent on the inclination of the vehicle.
[0099] When the door is closed, it will reach the same position, just beyond the half latch
position, and will then cause the electric motor to be switched on again, with reverse
polarity (to be described below). The motor then provides power-assisted door closing,
to ensure that the door is properly closed and latched. Again, the half latch position
is not possible, with power assisted closing. As the door commences full closure,
anticlockwise rotation of the latch bolt 11 accompanies clockwise rotation of the
smaller gear 40 together with the larger gear 50. After the first phase of such rotation,
the extension 33 of the pawl actuator 30 translates back downwards. The free play
between the pawl actuator and the pawl 20 allows the pawl 20 to ride over the slot
14 and into the slot 13, under a clockwise spring bias (not shown), without jamming.
As the tooth 24 lodges in the slot 13, the arrangement returns to the position shown
in Figure 19.
[0100] Without power assist, the latch can be controlled by the door handle through the
link arm 25. The mechanical interactions remain, and opening and closing the door
causes rotation of the motor spindle, but this simply provides a small amount of mechanical
resistance. Lifting the link arm 25 releases the pawl, allowing the door to be opened,
whereby the latch bolt 11 is turned clockwise by the striker 10. Again, the pawl actuator
30 is released from engagement with the gear 50 until the door is reclosed. It will
also be appreciated that since the mechanical sequence is the same, power assisted
closing can follow non power assisted opening, and vice versa. When the latch is operated
purely mechanically, it is capable of lodging in the half latch position, with tooth
24 of pawl 20 in notch 14. This is an additional convenience and safety feature.
[0101] A modification of the arrangement of Figures 10 and 18A, which provides door opening
and closing, is shown in Figure 22. As will be apparent, the abutment surface 231
on the shuttle 233 drives the pawl by way of its extension arm 232, moving it to position
232A. Continued motion in the same direction drives the latch bolt extension 37 to
its unlatched position 37A. As with the arrangement of Figure 18A, the notch 234 engages
a link lever (1810 Figure 18A) for electrical locking and unlocking.
[0102] An electric opening mechanism especially suitable for a boot or tailgate latch is
shown in Figure 23. The rotary output drive 50 of the motor 70 is coupled rigidly
with a leadscrew 240 which causes linear reciprocating movement of a shuttle block
242 which is intemally threaded in a nut portion 243 and which has an internal bore
to receive the leadscrew 240. An end abutment surface of the shuttle 242 engages and
drives the pawl 20 for door opening. As with other arrangements, a portion 244 of
the pawl is connected by a link 245 to an external manual control such as a handle
through a lever 246, to enable the door to be opened provided first the latch has
been unlocked by a key mechanism, an interior door knob or an electrical control (not
shown). The nut 243 and shuttle returns after each actuation to its neutral position,
as shown, by at least one of the following mechanisms: a return spring acting on the
nut; a return nut acting on the pawl; and repowering the motor so as to cause the
nut to move in direction D6. The nut 243 is constrained to move linearly, by suitable
means such as rails fixed to the housing.
[0103] In an alternative arrangement, the leadscrew 240 meshes with an internal thread 241
in the rotary drive gear 50, and the leadscrew is formed integrally with the shuttle
242. Further mechanical equivalent configurations will occur to the skilled reader.
[0104] A compact door latch arrangement is shown in Figure 24. The housing 250 is in the
form of a flat rectangular box with a rounded corner and a U-shaped opening for receiving
the striker 10. The housing comprises mutually opposed end plates 252 and a side wall
251 defining an internal compartment 253 for housing the electric motor 70 and rotary
output gearing 50. Cables 256, 258 for controlling respective levers 255 and 257 project
through the side wall and are connected to the levers by nipples held within end formations.
The particular connection which is preferred is described below with reference to
Figure 46.
[0105] It is especially important for the compactness of this arrangement that several components
are all mounted on the same pivot axis 21, including the pawl 20. This latch arrangement
provides electric locking and unlocking.
[0106] The pawl 20 has a lever arm formed with a fork 259 to enable it to be driven rotationally.
A pawl release lever 255 is pivotally connected on the pawl axis 21, for actuation
by an external manual control such as an interior or exterior door handle. Rotary
motion of the pawl release lever 255 is transmitted to the pawl fork 259 only by means
of a rotary coupling member 300, 400 which carries a dependent elongate lug 262 disposed
parallel to the pivot axis. Clockwise actuation of the pawl release lever 255 causes
its end notch 263 to engage the lug 262, which is then driven against the fork 259.
This leads the pawl 20 to its unlatching position, to allow the door to open.
[0107] The rotary coupling member 300, 400 comprises two components connected pivotally
at the pivot axis 21 but capable of sliding movement, normal to the pivot axis, by
virtue of an oval slot formed in both components 300, 400. Locking member 300 is constrained
to move linearly between the left-most position as shown in Figure 24, at which the
door is unlocked, and a right-most position at which the door is locked because the
pawl release lever 225 is no longer coupled to the pawl 20, i.e. it is rendered neutral.
A rotary sliding member 400 has an arcuate slot which rides over the pin 301 on the
locking member 300, and is integrally formed with the dependent lug 262. The slot
is sufficient to allow the rotary sliding member to rotate with the pawl release lever
255 when they are coupled by virtue of the lug 262. When the locking member 300 is
moved rightwards to its locking position at which it neutralises the pawl release
lever, the lug 262 is moved with it, so that it can no longer be engaged by the notch
263 of the pawl release lever.
[0108] The rotary coupling member 300, 400, is driven selectively by an output disc 500
with an eccentric pin, driven by the bevel gear 50 of the motor 70. The pin drives
the locking member 300 through a notch or other formation 302. Such coupling arrangements
will be described in greater detail, in various alternative forms, with reference
to Figures 25, 26, 35-38.
[0109] Mechanical locking and unlocking is achieved through lever 257, for example from
a key mechanism or interior door knob. This drives the locking member 300 and forces
the electric motor drive when it is not powered. Thus the latch arrangement provides
independent mechanical and electric locking and unlocking.
[0110] A member 254, of which only a portion is shown, also couples drivingly with part
of the locking member 300, for locking and unlocking.
[0111] The rotary sliding member 400 with the lug 262, which is permanently coupled with
the fork 259 of the pawl 20, is prevented from moving between its locking and unlocking
positions for as long as it is in the course of being actuated rotationally, by means
of a boss or elongate block 260 projecting from the housing. Whilst the fork 259 rides
over the boss 260, the lug 262 cannot move radially of the pivot axis 21 past the
boss 260, in either radially direction.
Anti-slam Locking
[0112] The boss 260 also has the desirable function of providing anti-slam locking of the
latch. The boss 260 prevents inadvertent locking of the door whilst the door handle
is held open and the pawl is in its unlatching position, by preventing sliding movement
of the locking member 300, due to the radial engagement of lug 262 with boss 260.
Thus if the door latch were unlocked and the door then slammed shut, the door could
not inadvertently be locked, since the rotary coupling member 300, 400 is held within
the housing.
[0113] Even without such locking arrangement with the boss 260, the latch arrangement can
be configured for anti-slam locking. In the configuration shown in Figure 24, and
also in the arrangements of Figures 25 and 26, the locked position of the locking
member 300 is to the right-hand side, away from the striker 10. The orientation of
the latch bolt is such that the door closes in the leftwards direction. Thus, if the
latch is unlocked before door closing, the locking member 300 will be fully to the
left, and any impact upon slamming the door will have no effect on its position. If
however the door is locked and the door is then slammed, the locking member 300 may
be forced, under the impact, to continue its motion leftwards to the unlocking position,
and it may rebound to its locking position, but either way there would be no inadvertent
movement from an unlocking to a locking position. Thus, the orientation of the latch
bolt and the path of the coupling member 300 are such that, in use, the locking position
is substantially further than the unlocking position of the coupling member 300 from
the striker 10.
Selective Electric Locking
[0114] Two alternative latch arrangements for electrical locking and unlocking will be described
with reference to Figures 25 and 26. Each arrangement has two pawl release levers
700, 800 for connection to external manual controls such as interior and exterior
door handles, and each corresponding generally to the pawl release lever 255 described
above with reference to Figure 24. Each pawl release lever is selectively coupled
to the pawl 20 by its own rotary coupling member 300, 400 and 350, 450 respectively.
Each such rotary coupling member comprises a locking member 300, 350 connected respectively
to a rotary sliding member 400, 450 which have analogous functions to the corresponding
components described above with reference to Figure 24. They are all disposed around
the common pivot axis 21, providing maximum compactness and simplicity, and enabling
the pawl release levers to have sufficient leverage over the pawl to be accommodated
within the housing.
[0115] In addition, each latch arrangement has a further lever 900 connected to an external
control mechanism through a cable 901, such as to a child-safety switch, or an interior
door knob, depending on whether the arrangement is to be used in a rear door or a
front door. This further lever 900 has a pivot point at 902 within the housing, and
is connected to a lever arm with an end pin 903 coupling with an appropriate one of
the rotary coupling members.
[0116] In the arrangement of Figure 25, the locking members 300 and 350 have respective
projecting pins 304 and 354 which engage with a cam pin 501 on the rotary indexing
and driving member 500. In Figure 25, the locking members are driven independently
in opposite directions, whereas in the arrangement of Figure 26 they may be driven
together, to reciprocate in the directions D7 and D8, although they may alternatively
be driven independently. The latch arrangements of Figures 25 and 26 are sufficiently
flexible to be adapted for use with child-safety locking and/or panic door opening,
and enable selective engagement of either or both exterior door handles. They may
also be integrated with electric locking, controlled by the same electric motor or
by a different motor.
[0117] In the case of Figure 25, for example, for use in front doors, the exterior door
handle would be connected to pawl release lever 700 through cable 701, and would be
lockable by the interior door knob through lever 900. The interior handle would drive
lever 800. For the rear doors, however, the connections with the door handles would
be reversed, and lever 900 would be redundant or else could be used as a mechanical
child safety lever.
[0118] The arrangement of Figure 25 operates as follows. Rotary coupling member 300, 400
drives lugs 410 and 420 between a left-most position, as shown, and a right-most position
at which lug 420 is free of notch 803 and lug 410 is free of notch 453. Lug 420 permanently
engages in the jaw of the fork 259 on the pawl 20.
[0119] Rotary coupling member 350, 450 has a lug 451 on the left-hand side which is capable
of being driven clockwise by notch 702 on pawl release lever 700. As mentioned above,
it is also coupled pivotally to lever 900 through pin 903. The rotary sliding member
450 is formed with a notch 452 capable of being driven clockwise by a lug 802 on the
pawl release lever 800. It is also formed with the notch 453 which drives lug 410
of the other rotary sliding member 400, when at its left-most position.
[0120] Thus actuation of lever 700 drives the pawl through lugs 451 and 420 only in the
position shown. If rotary sliding member 450 were to be moved to the left, then lug
451 would no longer couple with notch 702, and lever 700 would be neutralised.
[0121] Actuation of lever 800 through notch 803 drives the lug 420 directly, but only if
the rotary sliding member 400 is at its left-most position as shown. This in turn
drives the pawl 20.
[0122] Wherever the rotary coupling member 350, 450 is at its neutral, left-most position
(not shown), neutralising lever 700, it is automatically returned to its coupling
position, as shown, by the action of the other release lever 800 with its lug 802
acting on the notch 452 of rotary sliding member 450. Thus if for example the exterior
door handle is operated on a door latch in which the interior door handle has been
neutralised by a child-safety lever, subsequent operation of the interior door handle
serves to open the door; in other words, operation of the exterior handle overrides
the child-safety function. Similarly, this arrangement provides for a panic override
of door locking, enabling lever 800 to raise the interior door knob coupled to lever
900 when an interior front door handle is operated.
[0123] The arrangement of Figure 26 is operated analogously to that of Figure 25, except
that both rotary sliding members 400, 450 co-operate with the pawl fork at the right-hand
side of the arrangement. Corresponding parts are denoted with the same reference numerals.
Figure 26A shows schematically the detailed arrangement at the right-hand side.
[0124] These arrangements avoid the need for a mechanical child-safety lever, since the
selective operation of an interior door handle can be controlled electrically from
an electronic central control unit. The use of the exterior door handle as a mechanical
override allows the interior handle to be opened, and this is useful for police vehicle
use as well as for child safety.
[0125] The arrangements also enable double locking to be achieved, by rendering neutral
the interior door knob connected to lever 900 in Figure 25, for example. Thus a single
electric motor is capable of controlling double locking, selective locking of interior
and exterior handles, and child-safety control. Electrical child-safety locking is
possible even without any separate mechanical arrangement, by virtue of the selective
independent control of the interior door handle.
[0126] Existing door latches require a number of mechanical units for double locking, and
often employ two motors.
Continuation of Locking or Unlocking Function after Temporary Blocking by Mechanical
Door Handle Actuation
[0127] Pawl release lever 700 of Figures 25 and 26 is shown in its neutral position 700A
and its fully actuated position 700B in Figure 27. When actuated, at position d the
lug 420 of the corresponding rotary coupling member is capable of being driven only
partially from its unlocking, neutral position 420A towards its fully locking, coupling
position 420C. This is because the lug abuts at 420B against the edge of the lever
700. Once the door handle is released and it returns to position e, with the notch
raised to position 702A, the lug 420 is free to move from position 420B to its fully
coupling position 420C. In order to achieve this continued motion leftwards from B
to C, even after an initial attempt which was blocked, the electric motor could be
repowered, under the control of the central locking control unit 90. However, an alternative
mechanical arrangement is to provide a mechanical resilient bias which directs the
lug from 420B to 420C. Preferably, there is an over-centre spring arrangement whose
centre position of instability corresponds to the halfway position of the lug between
positions 420A and 420C, which is slightly to the right of the intermediate position
420B at which it engages the lever 700. Thus the lug is biased to the right until
it has moved to its midway position; beyond its midway position it is biased to the
left. Such over-centre spring arrangements are well known, and typically employ a
torsion spring whose ends are connected respectively to the lug and to the housing.
[0128] An alternative configuration for the rotary sliding members 400 and pawl 20 of Figures
25 and 26 is shown in Figure 28. The fork is formed on the rotary sliding member 400,
with fork arms 430 and 431 of different length, instead of being on the pawl. The
pawl is formed with a downwardly depending pin 20A engaging in the fork. This facilitates
separate sealing or isolation of the rotary coupling member and levers, which may
be sealed jointly with the drive gear and motor. The pawl and latch bolt may be more
easily separated from this sealed assembly, with the arrangement of Figure 28, because
the pin 20A can pass through a sealable opening in the housing over the pivot 21.
This can achieve better sound proofing and can improve the life of the latch actuator
by excluding grit and other abrasive materials.
Electromechanical Child-Safety Arrangement
[0129] An electromechanical child-safety arrangement for use with the aforesaid latch arrangements
is shown in Figure 29. A separate electric motor 70 drives a lever 194 pivoted at
195, by way of a sliding block 191 to which it is pivoted at 192 through a slot 193.
The block 191 is constrained to move linearly and is driven by a leadscrew 198 driven
by the motor through reduction gearing. The lever 194 at its pivoted end has a pin
196 connected to an actuation lever 197 capable of reciprocating linearly in directions
D3 and D4 between positions c and d, to operate the child-safety mechanism. This couples
the mechanism to the pawl selectively, as described above, for selective decoupling
of the interior door handle. The electrical control avoids the need for a mechanical
child-safety lever or switch in the rear door latch.
Combined Electrical Locking and Door Opening and Closing
[0130] The arrangements shown in Figures 30 to 38 enable a single electric motor to control
independent functions for the latch arrangement, such as electric door locking and
unlocking (central locking) and door opening and/or closing. Several independent innovations
are disclosed, as with the other arrangements.
[0131] The latch arrangement in Figure 30 has a rotary indexing and driving member 50 with
a single cam pin 30 having two neutral positions Np1 and Np2, and spring biased into
those positions by spring 1009 which also absorbs shock. Controlled operation in directions
D1 and D2 causes independent actuation of a lever arm 1001, for door locking, and
cam finger 1004 of a shuttle mechanism 1006. Electric locking is achieved by rotating
the lever 1001, against its return torsion spring 1002, in directions D11 or D12,
appropriately to actuate the pair of locking members 300 and 350 together. As shown,
the cam 1003 of lever 1001 rotates from a neutral position C to either extreme positions
C1, C2, depending on the rotary direction of the cam pin 30.
[0132] Door opening is achieved by the shuttle 1006 which has an abutment surface 1005 acting
on the lever 1008 of pawl 20. Door closing is achieved by the abutment surface 1010
at the lower end of the shuttle which abuts against the latch bolt extension 37 to
move it from position B to position B1. As shown, the cam finger 1004 moves between
a neutral position Np and extreme positions P1 and P2. As before, the shuttle is controlled
by a tension compression coil spring 1007.
[0133] The arrangement of Figure 31 shows how a single cam finger 1012 on the rotary indexing
and driving member 50 selectively controls three functions: the single lever 1001
of Figure 30 is replaced by two such levers 1010, 1011, equi-angularly disposed around
the rotary member 50. The cam finger 1012 has three neutral positions Np1, Np2 and
Np3, to which it is spring biased by means not shown. This enables the independent
control of the two locking members 300 and 350 as shown.
[0134] A further variant is shown in Figure 32 in which a fourth actuation member is selectively
driven by the cam finger 1012, and the four actuation members 1020 to 1023 are equi-angularly
disposed around the rotary member 50. This enables a single electric motor to control
the selective locking of two handles and electric door opening and closing, as in
Figure 31, and an auxiliary function, such as a child-safety operation. In a variant
of the arrangement of Figure 32, not shown, different cams 1012 could be disposed
in different planes spaced axially of the rotary member 50, as on a cam shaft, to
increase the flexibility of the multiple actuations.
[0135] A further variation is shown in Figure 33, especially suitable for use with a tailgate
or boot latch. The single cam pin 30 selectively drives pawl 20 through a rotary lever
1030 mounted co-axially with the pawl, and arranged with a dependent flange 1031 to
drive the pawl in direction D3, but to rotate in direction D7 freely without actuating
the pawl. Thus the cam pin 30 is able to rotate clockwise in direction D6 to rotate
the lever 1030 without being hindered by the pawl. The cam pin 30 also actuates a
lever arm 1034 for operating the locking member 300 which is also coupled to the key
mechanism through link 1033. The lock mechanism selectively couples the handle or
knob through linkage 245 to the pawl 20.
[0136] As with other arrangements, the rotary member 50 may be spring biased into its neutral
positions for example by a sinuous rotary cam surface against which the leaf spring
1037 is forced radially.
[0137] Figure 34 illustrates how the cam pin 30 can be arranged to drive two sliding locking
members 300 and 350 through appropriate pins or projections 304 and 354 respectively.
Projection 354 is moveable by the cam pin 30 between positions A, A1, A2 and A3; projection
304 is correspondingly moveable between positions B, B1, B2 and B3. The stable positions
of the projections 304, 354 are those positions on the broken line, shown as A1, A2
and B1, B2, and they are displaced between those positions by the cam pin 30 and they
return to those positions after the passage of the cam pin 30. In order to allow the
passage of the cam pin 30, they are resiliently moveable outwardly to the corresponding
extreme positions A, A3, B and B3. By way of example, the resilience is achieved,
as shown in Figure 35, by arranging for the projection on the locking members 300,
350 to take the form of a toggle 1050 pivoted at 1052 and biased into its central
position by torsion spring 1053 disposed on the pivot and held by and held by fixed
block 1054. The toggle or finger 1050 can be displaced rotationally to position P1,
to be returned to its neutral position P, by spring arm 1051. Similarly, it can be
displaced to position P2 to be returned to its neutral position by spring arm 1055.
[0138] Alternative resilient formations are of course possible. As shown in Figure 36, the
cam pin 30 is fixed, and rides over a V-shaped leaf spring 1070 retained within a
box formation in actuator 1080 which is part of one of the locking members, for example.
Alternatively, as shown in Figure 37, a pin or button 30 is mounted for sliding movement
in the housing either of the actuator of the rotary member 50, so that it can be depressed
to allow the passage of the co-operating cam.
[0139] In the arrangement shown in Figure 38, a rotary cam 1083 engages flexible elongate
arms 1081 and 1082, capable of resiliently deforming in the radial direction of the
rotary member 50 to allow the passage of the cam 1083 after actuation phase of rotation.
Key Operation Mechanisms
[0140] The operation of a key mechanism suitable for use with the latch arrangements for
example of Figures 25 and 26 will now be described with reference to Figures 29 to
44. Typical cylindrical key mechanisms have rotary outputs, and these need to be converted
to linear displacements of the locking members 300, 350, for example. This is achieved
by means of a specially-formed cam disc 5000 arranged to be driven by the key mechanism.
In the arrangement of Figures 39 and 41, the cam surfaces cause opposite linear motion
of the locking members; in the arrangement of Figures 40 and 42, they cause motion
in the same direction. In each case, the arrangement allows for independent mechanical
actuation of the same locking members.
[0141] As shown in Figures 39 and 41, the cam disc 5000 has wedge-shaped cam surfaces in
each of four quadrants Q1 to Q4, sloping steadily from low positions, in the plain
of the disc, to high positions, spaced radially from the plane of the disc sufficient
to displace the locking members the required linear distance. In this example, diametrically
opposite quadrants of the cam surfaces are on opposite faces of the disc. In the corresponding
example of Figure 40 and Figure 42, opposite quadrants of the cam surfaces are on
the same face of the disc. Areas D3 and D4 in Figures 39 and 40 represent directions
normal to the plane of the disc 5000, with which the locking members move.
[0142] In operation, the key drives the disc 5000 through a quarter turn either clockwise
or anti-clockwise, for locking or unlocking, and this motion is converted, by the
quadrant ramps, into corresponding linear motion of the locking members 300, 350.
[0143] The locking arrangement is shown further in Figure 43, which corresponds to the system
of Figures 39 and 41 in which the locking members move in opposite directions when
actuated. Adapter 2007 with a splined cylindrical recess 2006 is coupled to drive
the converter disc 5000, and it is capable of being driven by a key 2001 having a
splined end 2005. In this arrangement, angular tolerance is allowed over a cone 2003,
by virtue of the arcuate splines 2005. Rotation of the key in the direction 2004 drives
the adapter 2007 which in turn drives the disc 5000 in the appropriate rotary direction.
[0144] For extra security against theft, the tubular sleeve 2002 is disposed over the shaft
of the key 2001, and is coated preferably with an anti-stick material such as Teflon,
silicon or adhesive grease. This prevents the teeth of a saw from biting into the
shaft.
[0145] In alternative arrangements, a conventional key mechanism is coupled to the latch
by means of a cable or a rod or lever.
[0146] Some cylinder key mechanisms as shown in Figure 44 have a radial arm 2011 connected
to the key shaft 2001. With such a rotating lever 2011, the arrangements of Figures
44a and 44b can be used to drive the respective locking members 300, 350, by providing
rhombus-shaped apertures 2010 (Figure 44a) or 2100, 2200 (Figure 44b) in end flanges
of the locking members. The edges of the rhombus-shaped apertures act as cam surfaces
with the rotation of the lever 2011, and drive the locking members linearly in the
appropriate directions, either in the same direction, as in Figure 44a or in opposite
directions, as in Figure 44b. In the arrangements shown in Figure 44c, a key locking
arrangement 3003 has a radial cam 3004 which is arranged to engage in a notch 3005
of a lever 3001 pivoted and 3006 to rotate in the direction 3007. The level 3001 has
a projection which engages in a notch formed in an actuation level 3002 moveable linearly
in the direction 3008; this may of course may be one of the locking members 300, 350.
In the case of two locking members, two levers 3001 are provided on the same rotary
axis 3006.
Double locking
[0147] As an alternative or addition to the electric double locking arrangements described
above, a mechanical arrangement is shown in Figure 45. The key mechanism lever 451
is arranged to move parallel with the interior door knob mechanism 452, and the ends
of these mechanisms are coupled by a pivot lever 453 pivoted to both mechanisms as
shown. A torsion spring 455 mounted on the pivot axis of the lever 453 on the key
mechanism 451 has two limbs disposed around a stationary guide 456, and extending
also around a cam pin 457 on the lever 453. Rotation of the lever 453 away from the
neutral position shown in Figure 45 in either rotary direction tensions the spring
and the appropriate limb of the spring then acts on the pin 457 to return it to the
neutral position. A projection 460 on the key mechanism 451 prevents rotation of the
lever 453 beyond the position shown as AA.
[0148] Two parallel guide rails 458, 459 are fixed to the latch housing, and are of equal
length but displaced linearly as shown.
[0149] In the unlocked position as shown in Figure 45, the door can be locked by the key
mechanism moving in direction D1, causing the pin 457 to follow line BB. It can then
only be unlocked by the key mechanism, by reversing the process. If unlocking is attempted
by lifting the interior door knob 452 in direction D3, the lever 453 is rotated in
direction D4 so that the pin moves to position 457A at which it abuts and is retained
by the right hand guide rail 458. This constitutes double locking, dead locking or
super locking.
[0150] If, however, the door has been locked by the interior door knob 452, then the lever
453 will have been rotated in direction D2 so that the pin will have followed the
path AA, to the left of the guide rail 459, against which the pin 457 can slide. The
guide rail 459 extends downwardly sufficiently so as not to block the return of the
pin 457 along the line AA.
[0151] The pawl release levers 460, or indeed any actuator, may be constructed as shown
in Figure 46. During manufacture, a sheet metal blank 460 is formed with a transverse
flange 469 at one end, with circular apertures 461 and 462, aligned transversely on
the lever, being formed in both end portions. A slot 463 is also cut in the flange
469 so as to open the aperture 462 outwardly. During manufacture, the flange 469 is
folded at 467 and 468 so as to face the main portion 460 as shown, at which the apertures
461 and 462 are aligned. A cylindrical nipple 466 at the end of a cable 465, for example
a Bowden cable, is joined to the completed lever 460 by inserting the nipple from
the flange side into the apertures, slotting the cable 465 through the slot 463, and
then rotating the cable clockwise so as to lock it into position, at which it is rotatable
freely. It is also possible to trap the cable nipple as the flange is folded over,
during manufacture. This avoids the need for rivets, or the moulding of the release
lever. The lever can also be made more compact than if it were moulded.
Housing for Latch Actuator
[0152] As described above, the latch actuator can be formed in a compact box-shaped housing.
As shown in Figure 47, the housing can be formed from two opposed end plates 3017
and 3018 together with a side wall 3027. This arrangement can be secured to the door
frame 3023 by appropriate bolts 3024, 3025 and 3026 screwing respectively into an
axis 3019, the pivot axis 21 for the pawl 20 and other mechanisms 3020, 3021 and 3022,
and the pivot axis 15 for the latch bolt 11. These pivot axes 21 and 15 have axial
upward projections extending through the face plate 3017, and include radial enlargements
3015 and 3028 respectively.
[0153] An elongate closure plate 3010 has keyhole-shaped apertures 3012 and 3013, coupling
with the projecting pivot axes 3015 and 3028. During manufacture, once the latch arrangement
components have been assembled as shown, and the face plate 3017 inserted over the
three spindles, the closure plate 3010 is located with the larger circular portion
of each keyhole 3012, 3013 passing over the enlargements 3015, 3028. At this point,
a corresponding aperture 3011 in the closure plate is slightly misaligned with the
axis of the spindle 3019 as shown. The closure plate 3010 is then slid, in direction
A, over the face plate 3017, to lock it into position. The inner portions of each
keyhole slide over and retain the respective spindles on the pivot axes 21 and 15.
The closure plate then bears against the enlargements or studs 3015 and 3028. At this
point, aperture 3011 in the closure plate reaches the axis of the spindle 3019, and
a closure cap 3014 is inserted with a push fit through aperture 3011 and a corresponding
aperture in the face plate 3017, to secure the closure plate against sliding movement.
[0154] This arrangement allows non-destructive disassembly of the latch arrangement, simply
by removing the cap 3014 sliding the closure plate 3010 and then removing the closure
plate and disassembling the remainder of the latch assembly. Thus faulty components
can be replaced at any time.
[0155] Each end of the latch housing may have its own such closure plate.
Key Mechanism Operating Multiple Locks
[0156] As shown in Figure 48, a single rotary key mechanism 481 with an output radial lever
482, rotatable in either direction D1 or D2, can be arranged through respective cables
483 and 484 to actuate two different lock mechanisms 485 and 486 respectively. Bowden
cables are preferred, although alternative linkages are of course possible. In one
example, the key mechanism on a vehicle door can be connected by respective cables
to the latches on that door and on a different door. However, the key mechanism could
be elsewhere on the vehicle body accessible from outside. This reduces the number
of key mechanisms required and can make doors more streamlined. It is, of course,
applicable to other closures, not just doors, and three or more locks can be connected
through respective cables to the same key mechanism. Further, it is an adaptable system,
enabling the key mechanism to be located remotely from the latches.
Clutch Mechanism
[0157] As shown in Figure 49, the electrical drive to the mechanism for door opening or
closing can be decoupled by operation of the mechanical actuator such as the door
handle. This ensures that the mechanism cannot jam, even if there is a power failure.
The motor output spindle 60A drives a rotary output drive 60 from a spindle 492 extending
through the housing 491. This rotary drive 60 is connected to a splined gear 496 in
meshing engagement with an internally splined coupling gear 498. The coupling gear
498 is formed with a conical cam surface 497, and is spring biased axially into meshing
engagement with an output gear 1490 driving a rotary cam unit 1493, with a first cam
1495 for actuating the pawl by means of a link arm 1491, and a second cam 1494 for
driving the latch bolt 11. The coupling gear 498 selectively engages with the final
output gear 1490 by mutually opposed teeth in meshing engagement, at 499. The coupling
gear 498 moves axially away from engagement with the output gear when driven by a
link arm 495, whose end is also shown in Figure 50. An end flange 494 on the link
arm is formed with a wedge-shaped cam 4941 which co-operates with the conical cam
surface 497 to drive the coupling gear 498 axially, so compressing the spring. The
link arm 495 is resiliently biased by spring 493 to its neutral position as shown
in Figure 49.
[0158] Thus the link arm selectively decouples the clutch, and prevents the electric drive
from interfering with the mechanical drive and vice versa.