[0001] This invention relate to a friction hinge assembly for mounting an openable closure
member on a fixed frame.
[0002] The invention has been developed primarily, though not exclusively, in connection
with a friction hinge assembly for mounting an openable window frame in a fixed frame,
and in which a respective hinge assembly can be mounted on one or both of the top
and bottom horizontal frame members of the openable frame when the window is a "side
hung" window; alternatively, when the window is a "top hung" window, a pair of friction
hinge assemblies will be provided, arranged one on each respective frame member of
the opening window frame.
[0003] In certain circumstances, it is desirable to design a friction hinge assembly in
such a way that it allows limited or restricted opening movement only, and typical
maximum gap separation which might be allowed is about 100mm. The purpose of this
is to prevent children jumping out of an upstairs window, or may be required in institutions
to prevent residents jumping out also.
[0004] Restricted friction hinge assemblies are presently provided in both top hung windows
and also side hung windows, and test standards are set for this type of window, to
make the window able to resist any normal level of force used to force the window
open beyond the restricted arc of movement, since for obvious reasons any restricting
mechanism provided must be capable of resisting any ordinary attempt to override the
mechanism. Therefore, the authorised designs of restricted friction hinge must be
capable of withstanding test standards which are set, and therefore the restriction
mechanism provided must be quite strong.
[0005] However, in emergencies, e.g. to allow escape out of a restricted window when a fire
takes place, it is important to provide some authorised facility to override the restricting
mechanism. This may also be desirable for cleaning purposes, to allow a window to
be moved through a greater angle, to allow access to the outside face of the window
for cleaning purposes.
[0006] The invention therefore has been developed with a view to provide an improved design
of restricted friction hinge assembly, which is strong enough to meet test standards,
but which has a facility which allows the restriction mechanism to be overridden by
an authorised person in any particular situation in which it is required to allow
greater opening movement of the window, but to provide for automatic return of the
restriction mechanism to its ordinary restricted function upon subsequent closure
of the window. This latter feature is important, to provide a safeguard against unintentional
failure to return the restriction mechanism to its ordinary function, which might
otherwise occur in the absence of any automatically operating restoring arrangement.
[0007] According to the invention there is provided a restricted friction hinge assembly
for mounting an openable closure member, such as a side hung or top hung window frame,
on a fixed frame member of a fixed frame, said hinge assembly having a fixed guide
track which is securable to said fixed frame member and a linkage which is connectable
to a frame element of the openable closure member, and which is capable of carrying
out opening and closing movement relative to the fixed guide track, in which the linkage
comprises:
a first arm securable to said frame element;
a second connecting arm pivoted at one end to an end region of the first arm and pivoted
at its opposite end to the guide track via a slidable mounting block mounted for slidable
movement lengthwise of the guide track;
a third connecting arm pivoted at one end to the first arm and pivoted at its opposite
end to a fixed pivot point on the guide track; and,
a fourth control arm pivoted at one end to the guide track on the same mounting block
on which said second arm is mounted, said fourth arm also being pivoted at its opposite
end to the third arm at a position intermediate the ends of the third arm so that
the fourth arm extends substantially parallel to the first arm to form an approximate
parallelogram linkage therewith, and in which:
an elongate control element is connected to said movable slide block for movement
therewith during opening and closing movement of the linkage;
an abutment is mounted on the guide track and which has an operative position lying
in the path of travel of the control element to limit movement thereof and thereby
determine a required limit to the opening movement of the linkage;
the abutment is adjustable to a disabled and inoperative position out of the path
of movement of the control element and thereby to allow a greater extent of opening
movement of the linkage; and,
the abutment is automatically returnable to its operative position as the linkage
carries out closing movement whereby subsequent opening movement of the linkage can
again be restricted by limiting the movement of the control element.
[0008] A restricted friction hinge assembly according to the invention therefore is able
to provide restricted or limited opening of a window or other closure member, and
so as to provide any required maximum opening space, and prevent egress by children
or others during normal operation. However, the provision of the adjustable abutment
allows authorised personnel, having knowledge of the location and adjustability of
the abutment, to move the abutment to a disabled position out of the path of movement
of the control element, thereby allowing a greater extent of opening movement of the
linkage when required e.g. to obtain egress via the window in the case of a fire,
or simply to allow access to the outside of the window for cleaning purposes.
[0009] The automatic return of the abutment to its operating position may be obtained by
any suitable means, and including: (a) spring-loading of the abutment towards its
operative position or (b) providing interengagement between a part of the linkage
and the abutment as the linkage carries out its closing movement.
[0010] Therefore, upon subsequent return of the window to its closed position, the abutment
returns automatically to its operative position, and therefore subsequent opening
movement of the window is again restricted by the abutment limiting the movement of
the control element. This therefore provides a valuable safeguard, in that the operator
moving the abutment to the disabled position is not obliged to remember to return
it to the operative position for a subsequent restricted window opening operation.
[0011] The guide track is shaped to allow captive sliding movement of the slide block, in
the sense that it allows the slide block to move lengthwise of the guide track, but
is guided in the sense that it is not readily able to be displaced in a direction
perpendicularly away from the axis of the guide track.
[0012] Conveniently, the guide track therefore has a longitudinally extending flat base
surface over which the slide is movable, and short upstanding side walls which are
turned inwardly, to engage over at least part of the exposed surface of the slide
block and thereby hold it captive in the guide track.
[0013] With such an arrangement of guide track, it is preferred that the elongate control
element takes the form of a rod shaped easily to fit and slide lengthwise along one
of the side walls, and also be held captive therein.
[0014] The abutment is movable to the operative position in which it lies in the path of
travel of the control element, and by engaging the end thereof, and this provides
a strong resistance to any attempt to forcibly move the slide block a greater distance
lengthwise of the guide track, in any unauthorised attempt at forcing the closure
member (e.g. window) beyond its required restricted opening movement set by the engagement
between the abutment and the control element. In addition, this strong resistance
provided by engagement between the end of the control element and the abutment also
can allow the restricted friction hinge assembly of the invention to meet any required
test safety standards.
[0015] The abutment preferably takes the form of a stop element pivotally mounted on the
base of the guide track, and which may have a small upstanding projection, to allow
finger or thumb manipulation by authorised personnel, when it is required to adjust
the abutment to the disabled inoperative position. Such displacement of the stop then
defines a clear path of movement for the control element along one of the side walls
of the guide track, when authorised greater opening movement of the linkage and the
window is permitted.
[0016] The stop element may be biased so as to tend to move back to its operative position,
if required e.g. by spring loading. Alternatively, the abutment may be arranged to
maintain its inoperative position by frictional engagement with the base of the guide
track, but any suitable engaging element may be connected to the linkage, provided
that it is arranged so that it moves into engagement with the stop element during
the movement of the linkage to the closed position, during which time the control
element will be returning with the slide block to the closed position, when the control
element will move past the stop element as it slides lengthwise of the side wall of
the guide track. The arrangement is such that, after the facing end of the control
element has moved past the stop element, the stop element can then be moved back to
the operative position, in the path of travel of the control element to limit its
movement during a subsequent restricted opening movement of the linkage and the closure
member mounted thereon.
[0017] Conveniently, an engaging element provided on the linkage to engage the stop element
may comprise a depression, lug or the like mounted on the fourth arm, and which engages
the stop element as the fourth arm pivots about its three pivot connections (to the
guide track, to the first arm and to the fourth arm) during the closing movement.
[0018] It does not matter precisely at what stage the abutment is returned to its operative
position, provided that the control element has moved to a position in which it allows
the abutment to return to the operative position i.e. the return of the abutment to
the operative position can be at or near to the end of the closing movement of the
linkage to the fully closed position of the closing member.
[0019] In a further aspect of the invention, a friction hinge assembly can function as an
egress type of hinge as defined in claim 11, and optionally spring-loading is provided
to return the abutment automatically to its operative position.
[0020] A preferred embodiment of restricted friction hinge assembly according to the invention
will be described in detail, by way of example only, with reference to the accompanying
detail diagrammatic drawing, showing the hinge assembly in a restricted opening position.
[0021] Referring now to the drawing, a restricted friction hinge assembly according to the
invention is designated generally by reference 30, and which is intended to mount
an openable closure member, such as a top hung window or a side hung window, on a
fixed rectangular frame. Friction hinge assemblies will be well known to those of
ordinary skill in the art. and only the essential operating components are illustrated
in the drawing which will now be described.
[0022] The hinge assembly 30 has a fixed guide track 31 which is securable to a fixed frame
member, and the assembly 30 also includes a linkage, designated generally by reference
32, which is connectable to a frame element of an openable closure member, and which
is capable of carrying out opening and closing movement relative to the guide track
31 to allow opening and closing movement of the window or other closure member to
which it is secured.
[0023] The linkage 30 comprises a first arm 33 which is securable to the frame element of
the closure member, and which has a nose 34 at one end which can engage with an end
cap 35 at one end of guide track 31, when the linkage 30 is in a closed position,
to provide resistance to any attempt at forced opening movement of the window relative
to the fixed frame.
[0024] A short second connecting arm 36 is pivoted at one end 37 to an end region of the
first arm 33, and at its opposite end 38 to a slide block 39 which is held captive
by the inturned side walls 40 of the guide track 31, and which is movable lengthwise
of the guide track 31 during opening and closing movement of the linkage 30.
[0025] A longer third connecting arm 41 is pivoted at one end 42 to the first arm 33, and
at its opposite end (not shown) to a fixed pivot mounting provided at or near to an
end of the guide track 31 opposite to the end cap 35.
[0026] A fourth control arm 43 is pivoted at one end 44 to the same slide block 39 on which
second arm 36 is also pivotally mounted, and fourth arm 43 is pivoted at its opposite
end 45 to the third longer connecting arm 41 at a position intermediate the ends of
arm 41 so that the fourth arm 43 extends generally parallel to the first arm 33 to
form an approximate parallelogram linkage therewith.
[0027] The illustrated embodiment usually permits restricted opening movement only of the
linkage 30, and with a typical maximum window opening movement of about 100mm being
provided. To achieve this restriction to the opening movement, and necessary strength
to resist any forced attempts at overriding the restriction mechanism (and also to
meet any required test safety standards), an elongate control element is connected
to the movable slide block 39 for movement therewith during opening and closing movement
of the linkage 30, but which has its movement lengthwise of the guide track 31 limited,
by means described below.
[0028] The elongate control element takes the form of a control rod, shown by dotted outline
46, which is also held captive within one of the side walls 40 of the guide track
31, and which moves lengthwise thereof with sliding movement of the slide block 39,
until such time as it engages an abutment, designated generally by reference 47, which
is mounted on the base of the guide track 31 and which has an operative position which
lies in the path of travel of the control element 46 to limit the movement thereof,
and thereby determine a required limit to the opening movement of the linkage 30,
and therefore also of the window or other closure member mounted thereon.
[0029] The abutment 47 is adjustable to a disabled inoperative position out of the path
of movement of the control element 46, and thereby to allow a greater extent of authorised
opening movement of the linkage 30. The abutment 47, in the illustrated arrangement,
comprises a catch pivotally mounted on the base of the guide track 31, and which is
movable against frictional opposition by finger or thumb manipulation of an upstanding
lug or operating knob 48. In the illustrated arrangement, the pivotal adjustment of
the abutment 47 to the disabled position will be clockwise pivoting of the abutment
away from engagement with one of the side walls 40 of the guide track 31, and in a
direction towards, or in engagement with the opposite side wall of the guide track.
The frictional engagement with the base is such that the abutment 47 maintains either
the operative or the inoperative positions to which it is moved.
[0030] To provide for automatic return of the mechanism to its mode of operation in which
it restricts the opening movement, the linkage 30 is arranged to be capable of returning
the abutment 47 to its operative position as the linkage moves to its closed position,
whereby subsequent opening movement of the linkage can again be restricted by limiting
the movement of the control element 46.
[0031] When the abutment 47 is moved to the inoperative position, the control element 46
is able to slide past the abutment 47, engaging the side wall, as the linkage 30 continues
to pivot outwardly relative to the fixed guide track 31, thereby providing greater
opening movement of the window.
[0032] Upon subsequent closing movement of the window, the control element 46 slides past
the abutment 47 (which is still in its inoperative position), but after the end 49
of the control element 46 has moved clear of the abutment 47, the abutment can then
be returned automatically to its operative position, in which it will again lie in
the path of movement of the end 49 of the control element 46, to restrict the opening
movement.
[0033] The linkage may be provided with any suitable engaging means to return the abutment
47 to the operative position as the linkage 30 moves to the closed position, and in
the illustrated embodiment a simple lug or other depression applied to the underside
of the third arm 41 may have a path of travel whereby it can engage the upstanding
lug 48 of abutment 47, as the arm 41 pivots back to a position overlying the guide
track 31 when closing movement will be completed. The abutment 47 then moves back
to its operative position, and which takes place automatically upon closing movement
of the window, so that it is then in a state of readiness to apply restriction to
any subsequent opening movement of the window.
[0034] The illustrated embodiment therefore provides a simple and reliable, and also strong
restriction mechanism, which limits the opening movement, but which can be disabled
by authorised personnel, when greater opening movement is required, but which automatically
restores the mechanism to a mode of operation restricting subsequent opening movement
following closure of the window.
[0035] The means of release of the restriction mechanism is accessible, when the window
is only partially open.
[0036] The control element 46 which moves with the slide block 39 provides a simple but
effective means of controlling the manner by which the mechanism operates i.e. restricted
mode or authorised unrestricted opening mode, and the control element, or control
rod effectively extends the slide block 39, and by virtue of its small cross sectional
area, it only takes-up a small part of the available space defined within the guide
track, and allows the abutment 47 to be located robustly in the path of travel of
the control element when restriction to the opening movement is required.
[0037] When the abutment 47 is moved to the inoperative position, this can release the control
rod and allow it to move past the catch and allow the window to travel to a normally
fully opened position when authorised.
[0038] The embodiment illustrated in the drawings provides a restricted friction hinge assembly
of the type in which the second connecting arm 36 is pivoted at one end 37 to an end
region of the first arm 33 and is pivoted at its opposite end 38 to the guide track
31 via the slidable mounting block 39 mounted for slidable movement lengthwise of
the guide track 31.
[0039] The longer third connecting arm 41 is pivoted at one end 42 to the first arm 33 and
is pivoted at its opposite end to a fixed pivot point (not shown) on the guide track
31. Finally. the fourth control arm 43 is pivoted at one end 44 to the guide track
31 on the same mounting block 39 on which the second arm 36 is mounted.
[0040] However, in a further aspect of the invention, a modified embodiment may be provided,
which is able to function as an egress type of friction hinge assembly. Modification
will be made to the embodiment shown in the drawing, whereby the mounting block 39
is fixed, and the bottom pivot by which third arm 41 is pivotally mounted on the guide
track 31 comprises a slidable mounting. A control element, similar to control element
46, will then be connected to the movable slide block on which third arm 41 is pivotally
mounted, and an abutment, similar to abutment 47, will be mounted on the guide track
31 and have an operative position lying in the path of travel of the control element
to limit movement thereof and thereby determine a require limit to the opening movement
of the linkage 32. However, this abutment will be adjustable to a disabled and inoperative
position out of the path of movement of the control element, and thereby to allow
a greater extent of opening movement of the linkage 32, when it is required to function
as an egress hinge.
[0041] The embodiments disclosed herein comprise restricted friction hinge assemblies, but
it should be understood that these features may also be incorporated into a security
friction hinge assembly e.g. as disclosed in our co-pending UK patent application
No 9928846.6.
[0042] It should be noted, however, that the means disclosed to cause automatic return of
the abutment 47 from its disabled position and back to its window-opening limiting
position (the engagement of a lug on the underside of arm 41 with the button 48 of
abutment 47), is one example only. Other arrangements are possible, whereby the abutment
47 can automatically return to the limiting or operative position.
[0043] Thus, although not shown, the abutment 47 may be spring-loaded towards the limiting
position (in which it normally restricts the lengthwise movement of the rod 46). Simple
manual manipulation of push button 48 against the spring-loading allows the rod 46
to move lengthwise without being impeded, so as to permit larger opening movement
of the window. However, upon release of the push button, the spring-loading presses
the abutment 47 against the outer surface of the rod 46, and therefore as the window
is returned to the closed position the rod 46 slides against the abutment 47 until
the rod end 49 has moved past the abutment 47, and then the abutment 47 automatically
snaps back to its limiting position.
[0044] Although the spring-loading is not shown (and could be a tension or compression spring
as required), it could be a compression spring located between side face 50 of the
abutment 47 and the adjacent inturned flange 51 of guide track 31.
[0045] This alternative means of automatically returning the abutment 47 to the limiting
or operative position may also be provided when the hinge assembly is being employed
in the "egress" mode as referred to above.
1. A restricted friction hinge assembly (30) for mounting an openable closure member,
such as a side hung or top hung window frame, on a fixed frame member of a fixed frame,
said hinge assembly (30) having a fixed guide track (31) which is securable to said
fixed frame member and a linkage (32) which is connectable to a frame element of the
openable closure member, and which is capable of carrying out opening and closing
movement relative to the fixed guide track (31), in which the linkage (30) comprises:
a first arm (33) securable to said frame element;
a second connecting arm (36) pivoted at one end (37) to an end region of the first
arm (33) and pivoted at its opposite end (38) to the guide track (31) via a slidable
mounting block (39) mounted for slidable movement lengthwise of the guide track (31);
a third connecting arm (41) pivoted at one end (42) to the first arm (33) and pivoted
at its opposite end to a fixed pivot point (not shown) on the guide track (31); and,
a fourth control arm (43) pivoted at one end (44) to the guide track (31) on the same
mounting block (39) on which said second arm (36) is mounted, said fourth arm (43)
also being pivoted at its opposite end (45) to the third arm (41) at a position intermediate
the ends of the third arm (41) so that the fourth arm (43) extends substantially parallel
to the first arm (33) to form an approximate parallelogram linkage therewith, and
in which:
an elongate control element (46) is connected to said movable slide block (39) for
movement therewith during opening and closing movement of the linkage (32);
an abutment (47) is mounted on the guide track (31) and which has an operative position
lying in the path of travel of the control element (46) to limit movement thereof
and thereby determine a required limit to the opening movement of the linkage (32);
the abutment (47) is adjustable to a disabled and inoperative position out of the
path of movement of the control element (46) and thereby to allow a greater extent
of opening movement of the linkage (32); and,
the abutment (47) is automatically returnable to its operative position as the linkage
(32) carries out closing movement whereby subsequent opening movement of the linkage
(32) can again be restricted by limiting the movement of the control element (46).
2. A restricted friction hinge assembly according to claim 1, in which the guide track
(31) has a longitudinally extending flat base surface over which the slide block (39)
is movable, and short upstanding side walls (40) which are turned inwardly, to engage
over at least part of the exposed surface of the slide block (39) and thereby hold
it captive in the guide track.
3. A restricted friction hinge assembly according to claim 2, in which the elongate control
element (46) takes the form of a rod shaped easily to fit and slide lengthwise along
one of the side walls (40) of the guide track (31), and to be held captive therein.
4. A restricted friction hinge assembly according to any one of claims 1 to 3, in which
the abutment (47) takes the form of a stop element pivotally mounted on the base of
the guide track (31), and having a small upstanding projection (48) to allow finger
or thumb manipulation by authorised personnel, to adjust the abutment to the disabled
inoperative position.
5. A restricted friction hinge assembly according to claim 4, in which the abutment (47)
defines a clear path of movement for the control element (46), to move along one of
the side walls (40) of the guide track, when the abutment (47) is adjusted to the
disabled inoperative position.
6. A restricted friction hinge assembly according to claim 4 or 5, in which the abutment
(47) has frictional engagement with the base of the guide track (31), so as to tend
to maintain either its operative position, or its inoperative position.
7. A restricted friction hinge assembly according to any one of claims 4 to 6, in which
an engaging element (not shown) is connected to the linkage (32), and which is movable
into engagement with the stop element (47) during the movement of the linkage to the
closed position, and during which time the control element (46) being returnable with
the movement of the slide block to the closed position such that when the end (49)
of the control element (46) moves past the stop element, said engaging element can
return the abutment to the operative position.
8. A restricted friction hinge assembly according to claim 7, in which the engaging element
provided on the linkage (32) to engage the stop element comprises a depression, lug
or the like mounted on one of the arms of the linkage and which is engageable with
the stop element during the closing movement of the linkage.
9. A restricted friction hinge assembly according to any one of claims 1 to 5, in which
the abutment (47) is spring loaded towards its operative position, so as to be returnable
automatically to its operative position as the linkage (32) carries out its closing
movement.
10. A restricted friction hinge assembly according to any one of the preceding claims,
in which the second connecting arm (36) is a short arm and the third connecting arm
(41) is a longer arm.
11. A restricted friction hinge assembly (30) for mounting an openable closure member,
such as a side hung or top hung window frame, on a fixed frame member of a fixed frame,
said hinge assembly (30) having a fixed guide track (31) which is securable to said
fixed frame member and a linkage (32) which is connectable to a frame element of the
openable closure member, and which is capable of carrying out opening and closing
movement relative to the fixed guide track (31), in which the linkage (30) comprises:
a first arm (33) securable to said frame element;
a second connecting arm (36) pivoted at one end (37) to an end region of the first
arm (33) and pivotally mounted at its opposite end (38) on the guide track (31);
a third connecting arm (41) pivoted at one end (42) to the first arm (33), and pivotally
mounted at its opposite end to the guide track (31) via a slidable mounting block
mounted for slidable movement lengthwise of the guide track; and,
a fourth control arm (43) pivoted at one end (44) to the guide track (31) on the same
mounting block (39) on which said second arm (36) is mounted, said fourth arm (43)
also being pivoted at its opposite end (45) to the third arm (41) at a position intermediate
the ends of the third arm (41) so that the fourth arm (43) extends substantially parallel
to the first arm (33) to form an approximate parallelogram linkage therewith, and
thereby to form an egress type of friction hinge assembly, and in which:
an elongate control element (46) is connected to the movable slide block for movement
therewith during opening and closing movement of the linkage (32):
an abutment is mounted on the guide track (31) and which has an operative position
lying in the path of travel of the control element (46) to limit movement thereof
and thereby determine a required limit to the opening movement of the linkage (32);
the abutment is adjustable to a disabled and inoperative position out of the path
of movement of the control element (46) and thereby to allow a greater extent of opening
movement of the linkage (32) and to allow the friction hinge assembly to function
as an egress hinge assembly; and,
the abutment (47) is automatically returnable to its operative position as the linkage
(32) carries out closing movement from the egress position whereby subsequent opening
movement of the linkage (32) can again be restricted by limiting the movement of the
control element.
12. A restricted fringe hinge assembly according to claim 11, in which the abutment (47)
is spring loaded towards its operative position, so as to be automatically returnable
to its operative position as the linkage (32) carries out its closing movement.