Motor-driven lock set

Abstract

 A lock set particularly for use in access-control systems comprises a cylinder unit 1 based on a standard pattern which is key-operable from the outside and operable by a thumb turn from the inside. In place of the normal thumb turn, however, the cylinder unit has a coupling 10 into which fits a shaft 21 from a motor unit 2 mounted to the inside face of the door. In normal operation the motor 20 is actuated to unlock and then relock the door by turning the shaft 21 in opposite directions to correspondingly turn the cylinder cam 14. The extent of this movement is controlled by a limit/reversing switch 23 actuated by a cam 24 on the shaft 21. Operation from the outside can also be effected by key-operation of the cylinder unit and for emergency operation from the inside a thumb turn 7 is provided on the accessible end of the shaft 21. The permanent connection between the cylinder cam 14 and the shaft 21 means that the limit/reversing switch 23 is always in the correct position for subsequent operation of the motor 20 in the appropriate sense irrespective of whether the last locking or unlocking action was accomplished with the motor, thumb turn or key.

Description

[0001] The present invention relates to electrically-energizable lock sets such as may be used for the locking and unlocking of doors in access-control systems or for other purposes under remote control.

[0002] More particularly the invention is concerned with a lock set in which a lock bolt mounted in a door or other closure can be driven to extend and retract by an electrically-energizable motor housed in a unit mounted to the surface of one side of the door and suitably connected to rotate a cam or other operating member for the bolt. A device of this kind has certain advantages over the more usual form of electric locking involving a solenoid-­controlled pivoted strike on the door frame which releases the door without retraction of the lock bolt. Particularly in the case of retrofitting to an existing doorway, fitting a door-mounted motor unit should in general involve less time and effort than fitting an electric strike which requires considerable preparation - ­ or even replacement - of the door jamb to accept the bulky strike mechanism and wiring. The conventional fixed striking box which can be retained with a door-mounted motor lock will also usually resist greater forcing loads than the electric strike. In addition, lighter cabling can be used since the typical current consumption of an electric motor suitable for the service envisaged is a fraction of that of the typical electric strike solenoid.

[0003] A lock set of the kind stated is disclosed in United States patent specification no. 4126341. In this case a DC electric motor is connected through a friction clutch to a shaft carrying a bolt-actuating cam in fixed spatial relationship to the rest of the door-mounted unit. The motor can be energized in reverse senses to correspond­ingly rotate the cam in reverse senses for extending or retracting the bolt of an associated mortice lock. A further cam on the shaft operates a two-position reversing switch through which the electrical supply to the motor is controlled so as to set the limits of its rotation. That is to say the switch is connected such that in a first position it connects a DC supply when applied to one pair of its terminals to the motor to energize the same in one sense, and in its second position it connects a DC supply when applied to another pair of its terminals to the motor to energize the same in the opposite sense, and in either position it breaks the circuit which it makes in the other. The switch is controlled by its cam to change from its first position to its second after the motor has rotated the shaft in the direction and through the angle required to extend the lock bolt, and to change the switch back from its second position to its first after the motor has rotated the shaft in the direction and through the angle required to retract the lock bolt. In other words, after each occasion that the motor runs to extend or retract the bolt the switch is left in the condition in which it can only energize the motor to drive the bolt in the opposite sense to its previous movement. A key-­controlled locking cylinder may also be provided on the opposite side of the door to the motor by which the lock bolt can be extended and retracted through a further bolt-­actuating cam separate from and unconnected to the bolt-­actuating cam of the motor unit.

[0004] Certain drawbacks can, however, be recognised in the construction and operation of the above-described prior art lock set. In particular, the independent operation of the bolt-actuating cams of the motor unit and locking cylinder means that problems will arise with subsequent motor-actuation of the bolt if the bolt is left after any key-actuation in a condition different from that in which it was left after the last motor-actuation. For example, from the above description it will be understood that when the bolt has been, say, extended by the motor, the reversing switch will be left in the position in which it interrupts energization of the motor in the bolt-extending sense and will enable energization only in the bolt-­retracting sense. Consider that the bolt is subsequently retracted by a person using the key but not re-extended by the key after passage through the doorway. The reversing switch will not have been affected by this action. Consequently, any subsequent attempt to extend the bolt with the motor will be ineffective since the last movement which the reversing switch "remembers" is the previous bolt-extension by the motor. Clearly this state of affairs is prejudicial to the security of the installa­tion. Furthermore, the fixed-position connection between the bolt-actuating cam of the motor unit and the rest of its components means that the assembly is not readily adaptable to mounting on doors of different thicknesses.

[0005] Another lock set of the kind stated is described in United States patent specification no. 4438962. In this case there is a motor unit housing an electric motor connected to a segmental driving gear through a worm gear arrangement of severe reduction ratio. The driving gear is intended to mesh with a driven gear which is connected to a torque blade extending from a cylinder locking mechanism on the opposite side of the door, this torque blade operating to shift a mortice lock bolt in conventional fashion. The lock can be operated, therefore, alternatively by electrical energization of the motor or by turning a correct key in the cylinder mechanism, in either case to turn the aforesaid torque blade.

[0006] The segmental nature of the motor unit's driving gear is chosen so that during non-operative periods of the motor it is disconnected from its driving engagement with the driven gear. Rotation of the torque blade by the cylinder mechanism when the latter is being used to operate the lock, therefore, while being imparted to the driven gear is not also transferred to the driving gear. This arrangement is chosen because the gearing between the motor and the driving gear is such that it would prevent manual rotation of the torque blade through the cylinder mechanism if the de-energized motor was still effectively connected to it through the gear train.

[0007] While the lock set of US 4438962 does not, in normal operation at least, suffer from the same drawbacks as described above for US 4126341, it does suffer from drawbacks of its own. In particular, the impossibility of turning the torque blade against the resistance of the motor gear train means that special provision must be made to guard against any circumstance which will result in failure of the normal disconnection between the driving and driven gears of the motor unit, which would otherwise render the lock inoperable by the cylinder mechanism. Such circumstances could arise, as discussed in US 4438962, if there should be an electrical failure part-way through an operating cycle of the motor. It might also occur, however, if an incomplete rotation of the torque blade by means of the cylinder mechanism or by means of the additional thumb turm which is also provided on the motor unit, is followed by a motor operation so that the driving and driven gears engage out of their normal phase relationship. In US 4438962 a mechanism is provided for overcoming such problems by an axial movement of the cylinder mechanism or thumb turn to disengage the coupling between the torque blade and the now-jammed driven gear. This additional mechanism adds undesirably to the complexity and cost of the lock set, however. In addition, since the electrical switches which control the limits of motor operation respond to movement of the driven gear, once the coupling between the torque blade and the driven gear is broken in this way the whole mechanism might reach a similar condition to that discussed above in relation to US 4126341 in which subsequent operation of the motor is rendered nugatory by out-of-phase actuation of the limit switches.

[0008] It is an aim of the present invention to provide a motor-­driven lock set of the kind stated in which the above-­discussed drawbacks of the prior art can be overcome, and accordingly the invention resides in a lock set for a door or other closure comprising: a lock cylinder unit adapted for mounting in the closure, comprising a cam or other operating member for extending and retracting an associated lock bolt by rotation of the operating member in reverse senses, a cylinder locking mechanism which is key-operable from one side of the closure for rotating the operating member in reverse senses, and a first coupling member accessible from the other side of the closure through which the operating member can be rotated in reverse senses independently of the cylinder locking mechanism, rotation of the operating member by means of the cylinder locking mechanism, however, causing corresponding rotation of the coupling member; and a motor unit adapted for mounting to the surface of the closure on the said other side thereof, comprising an electrically-energizable motor in permanent driving connection with a second coupling member for rotating the same in reverse senses, and switch means responsive to the rotation of said second coupling member for interrupting energization of the motor when the latter has rotated that coupling member through a predetermined angular extent in the respective sense and for enabling energization of the motor to rotate that coupling member in the reverse sense to which it last rotated; said first and second coupling members being adapted for coupling together in permanent mutual rotary driving connection; and the gearing between said motor and second coupling member being chosen such as to permit manual rotation of said first and second coupling members through key-­operation of said cylinder locking mechanism while the motor is de-energized.

[0009] In use of a lock set according to the invention, all rotation of the operating member to extend or retract the lock bolt, whether caused by operation of the motor or turning of the opposite cylinder locking mechanism, will involve corresponding rotation of the second coupling member to which the switch means are responsive. It is thereby ensured that the position of the switch means at any time always represents the last movement of the operating member and problems of non-actuation by the motor following a key operation are avoided. It is readily possible to design the complementary form of the two coupling members, e.g. as non-circular spigot and socket members engageable at various depths to transmit rotation, so that the lock cylinder unit and the motor unit can be installed in a range of relative dispositions suitable for closures of different thicknesses. Moreover, no mechanisms are required for disconnection of the motor from the operating member when operation by the cylinder mechanism takes place.

[0010] These and other features of the invention will now be more particularly described, by way of example, with reference These and other features of the invention will now be more particularly described, by way of example, with reference to the accompanying drawings illustrating one preferred embodiment of a lock set comprising a cylinder unit and motor unit in accordance with the invention, and in which:

Figure 1 is an elevation of the two units as assembled together;

Figure 2 is an axial section through the cylinder unit;

Figure 3 is a partial elevation of the internal components of the motor unit;

Figures 4 and 5 are respectively sections on the lines IV-­IV and V-V of Figure 3; and

Figure 6 is a schematic diagram of the electrical supply circuit for the motor unit.

[0011] The lock set shown in the drawings is particularly useful for the conversion of an existing keyed locking system to an access-control role in which doors are locked and unlocked electromechanically, although it could also be fitted as original equipment in new access-control installations. As shown in Figure 1, it comprises a lock cylinder unit 1 and a motor unit 2, the details of both of which will be more fully described hereinbelow. The housing 3 of the cylinder unit 1 in the illustrated embodiment is of equivalent section and dimensions to a known standard double cylinder and is fitted through the casing of a conventional mortice lock (not shown) so as to locate its central operating cam 4 correctly to actuate the lock bolt, all in known manner. Most conveniently the unit 1 simply replaces the original locking cylinder of the existing mortice lock in installations where a keyed cylinder locking system is being converted to electromechanical operation. The motor unit 2 is shown to comprise a casing 5 within which the motor and other components to be described are housed, and a plate 6 through which the assembly is attached to the face of the door. A knob 7 is also shown for manual override of the motor as described below.

[0012] Referring to Figure 2, this illustrates the construction of the cylinder unit 1. Borne in one end of the housing 3 is a rotor 8 which is in permanent driving engagement with the cam 4 through a cross-pin 9. At its free end this rotor is formed with a socket 10, the rotor 8 constituting the aforesaid first coupling member in this embodiment of the invention.

[0013] The other end of the housing 3 contains a cylinder locking mechanism. In the illustrated embodiment this mechanism is of the known kind comprising three rows of spring-­biased pin-tumblers 11 (of which only one row appears in the drawing) which cooperate with respective depressions 12 cut in the two flanks and an edge of a correct key 13 to unlock the key-rotor 14 for turning in the housing 3, although in principle any other known kind of cylinder locking mechanism could be used. Normally the rotor 14 is uncoupled from the cam 4 but when the key is inserted, as shown in the drawing, it presses in a sliding coupling member 15 against a plunger 16 biased by a spring 17, so that the member 15 enters a recess in the front face of a bush 18, which latter is in rotary driving engagement with the rotor 8 and cam 4 by virtue of the cross-pin 9 extending through all three components. In the event that the recess in the bush 18 is, for any reason, mis­aligned with the coupling member 15 when the key 13 is inserted, the whole assembly of plunger 16 and bush 18 can be pressed in against a second, stiffer spring 19 to permit the key to set the tumblers 11 and release the rotor 14, and the bush 18 will snap back over the member 15 to establish the drive connection between the rotor 14 and cam 4 as soon as the key has been turned through the angle required to align the member 15 with the bush recess. In fact this cylinder unit can be identical to a known standard pattern of double cylinder which provides for key-operation from one side of a door and thumb turn operation from the other side, except for the provision of the socket 10 in place of the normal thumb turn fitting.

[0014] Turning to Figures 3-5 the unit 2 includes a 24v DC electric motor 20 (with gearbox) arranged to drive a horizontal shaft 21 through bevel gears 22. As most clearly shown in Figure 5, the shaft 21 is of a truncated circular cross-section. The socket 10 in the rotor 8 of the cylinder unit is of complementary cross-section to the shaft 21, and when the unit 2 is assembled to the door the free end of shaft 21 enters the socket 10 to establish a rotary drive connection from the motor 20 to the bolt-­operating cam 4, the shaft 21 thus constituting the aforesaid second coupling member in this embodiment of the invention. The two units 1 and 2 can be coupled together in this way over a range of door thicknesses, determined by the available depth of the socket 10.

[0015] In use of this equipment for an access-control application, the motor unit 2 is mounted to the door on its internal face - that is to say on the side of the doorway into which access is to be controlled - and the keyhole for the cylinder locking mechanism is on the external side of the door. The motor unit can be used with any convenient form of authorisation device - such as a card reader, numeric keypad, biometric sensor or the like - to gain entry through the doorway from the outside, and a simple push-button to request exit from the inside.

[0016] On operation of either of these means an associated control unit supplies a DC voltage of appropriate polarity to the motor 20 so that it drives the cam 4 through 360° in the corresponding sense to retract the lock bolt, and the door can be opened. Subsequent closure of the door is sensed by a reed switch or other convenient device and this event causes the supplied polarity to be reversed, so that the motor 20 now drives the cam 4 through 360° in the opposite sense to extend the lock bolt once more.

[0017] Clearly, energization of the motor 20 must be controlled so that the cam 4 will stop after each bolt-actuation at the appropriate position from which to commence its subsequent actuation when required, and this is achieved through switch means responsive to the rotation of the shaft 21 as will now be explained.

[0018] Mounted within the motor unit is a double-pole, double-­throw electric switch 23. This switch is operated by a cam 24 which is borne around, but not keyed to, the shaft 21. This cam is capable of limited angular movement within a range permitted by a fixed pin 25 extending into an arcuate slot 26 in the rear face of the cam. In its anti-clockwise position, (in the sense of, and as shown in, Figure 5), the lobe 27 of the cam 24 is released from the operating button 28 of the switch 23. When moved to its clockwise position, however, the lobe 27 depresses the button 28. The cam 24 is itself controlled by a finger 29 fast on the shaft 21 and which can turn the cam by abutment with a projection 30 on the front face of the cam. When the shaft 21 rotates through 360° clockwise from the position shown in Figure 5 the finger 29 does not move the cam 24 until it abuts one flank of the projection 30 during the final part of the rotation to shift the cam and depress the button 28 after one complete revolution. Similarly, when the shaft 21 is rotated back anticlockwise from that position the finger 29 abuts the other flank of the projection 30 during the final part of the rotation to shift the cam and release the button 28 after one complete revolution. In other words, this mechanism causes the switch 23 to change from one condition to the other at the end of each successive revolution in the reverse sense from the preceding one. A leaf spring 31 applies a light frictional restraint against the turning of the cam 24 to overcome any tendency for the cam to be entrained by the rotating shaft and finger 21/29 before the projection 30 is encountered by the finger 21.

[0019] The circuit through which the motor 20 and switch 23 are connected to a reversible DC power supply 32 is shown in Figure 6. The switch 23 has two parallel sets of terminals T₁, T₂, T₃. In one condition of the switch the respective T₁ terminals are connected to the respective T₂ terminals and in the other condition of the switch the respective T₁ terminals are connected to the respective T₃ terminals.

[0020] For the purposes of the following description it is assumed that the motor unit 2 is mounted such that in the locked condition of the door the cam 24 and switch 23 are in the position shown in Figure 5, in which the switch terminals T₁ and T₂ in each set are connected. When an "unlock" command is given through the above-mentioned authorisation device or push-button the power supply 32 applies a positive voltage at terminal I₁ to the circuit of Figure 6. Current therefore flows through the circuit which is made from I₁ through line L₁, diode D₁ the lower T₂ and T₁ terminals of switch 23, line L₂, motor 20 and line L₃ to I₂. The motor 20 consequently runs in the direction appropriate to turn the cam 4 to retract the lock bolt (clockwise in the sense of Figure 5) until, after one revolution of the shaft 21 and cam 4, the cam 24 shifts the switch 23 to its button-depressed condition. This breaks the circuit through the T₁ and T₂ terminals of the switch and connects the T₁ and T₃ terminals in each set together. The flow of energizing current through the motor is accordingly interrupted and the poles of the motor are short-circuited through line L₂, the lower T₁ and T₃ terminals, diode D₃, line L₄ and line L₃. The motor therefore stops virtually instantaneously. Furthermore, although the switch terminals T₁ and T₃ in each set are now connected, current cannot flow through the circuit from I₁ through L₁ to the upper T₃ terminal because of the presence of diode D₂.

[0021] When, however, a subsequent "lock" command is given through the above-mentioned reed switch or similar device when the door is closed, the power supply 32 applies a positive voltage at I₂. Current can therefore now flow through the circuit which is made from I₂ through line L₃, motor 20, Line L₂, the upper T₁ and T₃ terminals of switch 23, diode D₂ and line L₁ to I₁. The motor 20 consequently now runs in the direction appropriate to turn the cam 4 to extend the lock bolt (anticlockwise in the sense of Figure 5) until, after one revolution of the shaft 21 and cam 4, the cam 24 shifts the switch 23 back to its button-released condition. This breaks the circuit through the T₁ and T₃ terminals of the switch and connects the T₁ and T₂ terminals in each set together. The flow of energizing current through the motor is accordingly interrupted and the poles of the motor are short-circuited through lines L₃ and L₄, diode D₄, the upper T₂ and T₁ terminals, and line L₂. So again the motor stops virtually instantaneously. Furthermore, although the switch terminals T₁ and T₂ in each set are now connected, current cannot flow through the circuit from I₂ through line L₃, motor 20, line L₂ and the lower T₁ and T₂ terminals to line L₁ because of the presence of diode D₁.

[0022] In this way, the motor 20 is controlled to perform appropriate single revolutions of the cam 4 in reverse senses in response to each successive "lock" and "unlock" command.

[0023] In the event of any electrical failure of the motor unit 2, emergency unlocking of the door from the inside can be achieved by turning the knob 7 accessible on the outside of the casing 5, which is mounted directly on the proximal end of the shaft 21. Furthermore, unlocking of the door from the outside can also be performed independently of the access-control system by authorised holders of a correct key 13 for the cylinder mechanism in unit 1. Any rotation of the cam 4 by these means to unlock (or lock) the door will involve corresponding rotation of the shaft 21 and operation of the switch 23. In particular, this means that when the door is unlocked with the key the switch 23 is moved to the position in which correct energization of the motor 20 is ensured when the subsequent "lock" command is given by the access-control system on closure of the door.

[0024] It will furthermore be appreciated that whenever the lock is operated by turning the key 13 or knob 7, thus rotating the shaft 21, the de-energized motor 20 will also be turned over through its geared connection to this shaft. While this inevitably imposes a certain resistance to turning the key or knob, by judicious selection of the gearing between the motor and shaft 21 this manual operation can be catered for while maintaining adequate speed and torque characteristics for the motorised operation of the shaft. In one particular implementation of the illustrated mechanism which performs well under both motorised and manual operation the motor 20 is an "escap" (registered trade mark) 28L28-416E 24V DC unit of 7.6W power output, having a nominal (unloaded) running speed of 5300 rpm and stall torque of 55 mNm. It is fitted with an "escap" R22 planetary gearbox providing a 19.4:1 reduction ratio, and the bevel gears 22 provide a further reduction of 2:1.

Claims

1. A lock set for a door or other closure comprising: a lock cylinder unit (1) adapted for mounting in the closure, comprising an operating member (4) for extending and retracting an associated lock bolt by rotation of the operating member (4) in reverse senses, a cylinder locking mechanism (11,14,15) which is key-operable from one side of the closure for rotating the operating member (4) in reverse senses, and a first coupling member (10) accessible from the other side of the closure through which the operating member (4) can be rotated in reverse senses independently of the cylinder locking mechanism (11,14,15), rotation of the operating member (4) by means of the cylinder locking mechanism (11,14,15), however, causing corresponding rotation of the coupling member (10); and a motor unit (2) adapted for mounting to the surface of the closure on the said other side thereof, comprising an electrically-energizable motor (20) in permanent driving connection with a second coupling member (21) for rotating the same in reverse senses, and switch means (23) responsive to the rotation of said second coupling member (21) for interrupting energization of the motor (20) when the latter has rotated that coupling member (21) through a predetermined angular extent in the respective sense and for enabling energization of the motor (20) to rotate that coupling member (21) in the reverse sense to which it last rotated; said first (10) and second (21) coupling members being adapted for coupling together in permanent mutual rotary driving connection; and the gearing between said motor (20) and second coupling member (21) being chosen such as to permit manual rotation of said first (10) and second (21) coupling members through key-operation of said cylinder locking mechanism (11,14,15) while the motor (20) is de-energized.

2. A lock set according to claim 1 wherein the said coupling members are formed respectively as complementary non-circular spigot (21) and socket (10) members engageable at various depths to transmit rotation.

3. A lock set according to claim 1 or claim 2 wherein said cylinder unit (1) comprises a housing (3) bearing two coaxial rotors (8,14) and a central rotatable said operating member (4); a first said rotor (8) being in permanent driving engagement with said operating member (4) and constituting, or being engaged with, said first coupling member(10); and the second said rotor (14) normally being disengaged from said operating member (4) and rotationally locked to said housing (3) by key-operable tumblers (11), insertion of a correct key (13) into said second rotor (14) serving to release that rotor (14) for rotation and to place that rotor (14) in driving engagement with said operating member (4).

4. A lock set according to any preceding claim wherein said second coupling member is constituted by, or engaged with, a shaft (21) which is driven by said motor (20) to perform single 360° revolutions in reverse senses for respectively extending and retracting the lock bolt and said switch means comprise a two-position switch (23) responsive to the rotation of said shaft (21) to change from one position to the other alternately at the end of each such revolution.

5. A lock set according to claim 4 wherein said switch (23) is actuated by a cam (24) operated in turn by an element (29) fast with said shaft (21) with lost motion between said element (29) and cam (24) whereby the cam (24) is operated to change the position of the switch (23) only towards the end of a said revolution of the shaft (21).

6. A lock set according to claim 5 wherein said cam (24) is itself borne around, but not in driving engagement with, said shaft (21).

7. A lock set for a door or other closure comprising: a lock cylinder unit (1) adapted for mounting in the closure, comprising an operating member (4) for extending and retracting an associated lock bolt by rotation of the operating member (4) in reverse senses, and a cylinder locking mechanism (11,14,15) which is key-operable from one side of the closure for rotating the operating member (4) in reverse senses; and a motor unit (2) adapted for mounting to the surface of the closure on the other side thereof, comprising an electrically-energizable motor (20) for rotating said operating member (4) in reverse senses, and switch means (23) for interrupting energization of the motor (20) when the latter has rotated the operating member (4) through a predetermined angular extent in the respective sense and for enabling energization of the motor (20) to rotate that member (4) in the reverse sense to which it last rotated; the motor (20) being connected to the operating member (4) through a shaft (21) which performs single 360° revolutions in respective senses for respectively extending and retracting the lock bolt and said switch means comprising a two-position switch (23) responsive to the rotation of said shaft (21) to change from one position to the other alternately at the end of each such revolution.

Drawing