GB2185526A

GB2185526A - Door closure mechanism

Info

Publication number: GB2185526A
Application number: GB08701357A
Authority: GB
Inventors: Andrew Sullivan
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-01-22
Filing date: 1987-01-22
Publication date: 1987-07-22
Also published as: GB8701357D0

Abstract

The mechanism comprises spring-loaded pulling means (4,5, Figure 1) adapted to be mounted on one of a door panel (2) and frame (1), and a latch member (7) for mounting on the other of the panel and frame. The latch member (7) is adapted for engagement by said pulling means (4,5) so as to assist in the final stage of door closure. The arrangement is such that withdrawal of the latch member (7) on opening of the door (2) resets the spring-loaded pulling means (4,5) for the next closure operation. Alternatively, a door-mounted, spring-biased jaw (115, Figure 4) is held open by a retractable detent (116). With door closure, a jamb-mounted, fixed head cams the detent to retract, and the jaw is spring-urged to engage behind the head and close the door. A bolt (108) is urged through a hole (117) to lock the jaw and the door. The bolt may be retracted by a twist handle (123), a rocker plate (129) or a push button (130). Door opening re-pivots the jaw (115), and allows the detent (116) to extend to hold the jaw against its spring bias. <IMAGE>

Description

SPECIFICATION A door closure mechanism The invention relates to a door closure mechanism, particularly but not exciusivelyfor a fire or security door requiring to be fully closed automatically.

It is well known for doors to be fitted with closure devices. One example is a torsion-spring-loaded lever acting on an external surface ofthe door. An- other example is a built-in device of the kind described in British Patent No. 1 044911 in which a cylinder containing a coil spring is let into the hinged edge of the door, the spring being anchored to an adjacent partofthedoorframe bya chain so that opening of the door causes compression of the spring, the stored energy ofthe spring being used to return the door to the closed position.

A problem with both these door closure devices is that the closure force in the final part of the travel of the door is not readily adjustable and slamming of the door may therefore occurwith consequent noise anddangertoyoung children who maygettheirfin gers trapped. It is known to avoid this problem by fitting a dashpotfor damping the closure movement but commercially available dash pouts are expensive and incapable of concealed fitmentto the door. I have proposed in my copending PatentApplication No. 86 27681 to overcome this problem by providing adamping devicefordampingthefinal partofthe closure movement ofthe door.

However, the known closure devices suffer from an additional disadvantage brought about by air damping ofthefinal closure movement ofthe door.

This effect is particularly apparent in small rooms wherethe principal airflowintoandoutoftheroom is through the door opening. In the case ofan in- wardly opening doorthefinal closure movement (i.e.

the short level of the door between contact ofthe door panel with the doorframe and the final latched full closure of the door) is resisted by a vacuum effect while in the case ofan outwardly opening doorthe volume of air in the room acts as a cushion resisting the final closure movement.

According to the present invention there is provided a door closure mechanism comprising springloaded pulling means adapted to be mounted on one ofthe door panel and frame, and a latch member adapted to be mounted on the other of the door panel andframeforengagement by said pulling means so as to assist in the final stage of door closure, the arrangement being such that withdrawal ofthe latch member on opening ofthe door resets the spring-loaded pulling means for the next closure operation.

Preferably, the spring-loaded pulling means has at least one jaw and the latch member is adapted on engagement with the pulling means to initiate pulling movement of the jaw.

The latch member is preferably a stud having a shaped head adapted to perform said resetting and initiating operations.

The door closure mechanism may be provided in addition to a conventional door latching mechanism.

Alternatively, it is possible to provide an integrated design obviating the need for two separate mechanisms. In accordance with this embodiment of the invention a separately (preferably manually operable) locking element is utilised to lock the spring loaded pulling means (which may for example be a single jaw) in the closed position thereof in which it engages with the latch member.

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which : Figure lisa diagrammatic, perspective and partially exploded view of one embodiment of door closure mechanism in accordance with the invention shown in a position of use; Figure2 is a diagrammaticview of the same mechanism immediately before the final closuremovement of the door; Figure 3 is a similarview immediately after initiation ofthe final closure movement of the door; Figure 4 is an exploded perspective view of that part of a further embodiment ofthe invention that is mounted on the door panel; and Figure 5 is a perspective view of the cooperating partofthe door closure mechanism ofthatshown in Figure 4that is mounted on the doorframe.

ReferringnowtoFigurel ofthedrawings,theopening side of a door is indicated in chain line with the door frame indicated at 1 and the door panel at 2. The door panel 2 is hinged at its vertical side remote from that shown in the drawing and closes onto the frame 1 in the direction of the arrow1. A conventional door latching mechanism is provided but is not shown because it plays no part in the present inven tion. The door closure mechanism is provided well above the door latch device so as to be out ofthe reach of small children.The closure mechanism comprises a base 3 let into the door frame 1 and mounting a spring-loaded pulling means comprising two jaws 4,5 and a trigger 6 which interacts with an actuating head 7 of a latch member8 in the final part of the closure movement of the door.

The base 3 is made of sheet metal which is formed to provide a cavity beneath the exposed surface of the base. In this cavity is mounted a sub-assembly 9 comprising the trigger 6 and two pegs 9,10 all three of which are shown projecting through respective openings in the outerweb of the base 3 (Figure 1).

The trigger 6 is mounted on a spindle 11 for rocking action between two stable positions in which the pegs 9, 10 extend from the base 3 to prevent closure movement ofthe jaws 4,5 (as shown in Figure 1) or are retracted to release the jaws (Figure 3).

The left-hand edge of the base 3 as seen in the drawing forms a recess which is open in the direction ofthe door panel 2. Pivotally mounted in this recess on respective pins 12, 13 are the jaws 4,5 each of which is attached to the base of the recess by are- spective compression spring 14, 15. Each jaw 4,5 has a body of U-shaped profile terminating in two fingers which are off-set with respect to the fingers ofthe otherjawso asto interdigitatetherewith during part of the travel of the jaws into and out ofthe position shown in Figures 1 and 2 (see the overlapping ends of the jaws in Figure3).

The latch member8 is in the form of a stud fixed to and projecting from a mounting plate 15screwedto the door panel 2. The actuating head 7 ofthe latch member 8 has an approximately lozenge shaped end section so as to provide on its front and rear surfaces a vertical face flanked by inclined jaw-spreaderfaces.

Theframe-adjacent side face of the actuating head 7 (to the left in Figure 1 ) is set to a small clearance with the exposed surface ofthe base 3 in the final closure movement ofthe door.

The door closure mechanism operates as follows.

Starting with the position shown in Figure 1 and 2, the door panel 2 continues its closure movement onto the frame 1 in the direction of the arrow Al thereby causing the latch member 8 to move in the direction ofthe arrowA2 onto the base 3 and in particular onto the outer ha If of the surface of the trigger 6 lying flush with the base 3.Continued movement of the actuating head 7 causes,firstly,thefrontjaw- spreaderfaces to spread the jaws 4,5 slightly apart so as to relieve the pegs 9, 10 from the jaw pressure tending to hold them in the extended position, and, secondly, the adjacent side face of the actuating head 7 engages the ramp surface formed by the inward half ofthe trigger so rocking the trigger into its second stable position thereby retracting the pegs 9, 10 and removing the obstaclesto closure movement ofthe jaws 4,5 (i.e. the pegs 9, 10 and the inward half of the trigger 6 in its initial setting).As shown in Figure 3, the fingers of the jaws 4,5 are nowfree to engage behind the shaped head 7 ofthe latch member8and drawthedoorpanel 2to itsfully closed position by the force of the springs 14,15.

When the door is now reopened,thejaw-spreader faces at the rear of the actuating head 7 slide along the fingers of the jaws 4,5 to spread the jaws into their open position. The side face of the actuating head 7 passes over the inward half of the surface of the trigger 6 (now flush with the base 3) and rides onto the ramp surface formed by the outer part of the trigger 6 so causing the trigger to rock back into its initial position shown in Figure 1 in which the pegs 9, 10 and the inner part of the trigger 6 again prevent closure movement ofthe jaws 4,5. The closure mechanism is thus resetforthe next closure operation.

It will be appreciated that numerous modifications may be madeto the embodiment of Figures 1 to 3 without departing from the scope ofthe invention.

For example, the closure mechanism may be positioned elsewhere on the door, for example on top of the door. Alsotthe positions of the base and latch member may be reversed with the latch member being mounted on the frame and the base being attached to the door panel, although in the embodi mentdescribed above it is preferred to attach the base to the frame. It is also possible to provide the closure mechanism with a single jaw operating in an analogous manner or, alternatively, to replace the jaw system by some other kind of gripper device serving a similar function.

Referring now to Figures 4 and 5 of the drawings, a doorto which the exemplary closure mechanism is fitted comprises a door panel 101 (Figure 4) the free vertical edge of which is shown to the right in the drawing (the opposite vertical edge which is hinged to the frame being to the left and not shown) which closes onto a doorjamb 102 shown in Figure 5.That part of the closure mechanism mounted on the door panel 101 comprises a locking bolt assembly mounted within the door panel and a plate assembly fixed in a recess 103 atthefree vertical edge of the door panel 101. For the purpose of receiving the locking bolt assembly, the door panel 101 is provided with a blind bore 104 extending at right angles to the free edge of the door panel 101 and opening intothefloor of the recess 103.The blind bore 104 is crossed by a transverse bore 105 which opens to opposite sides of the door panel 101. A cylindrical sleeve 106 is seated in the blind bore 104and hasopposed elongateslots 107 (only one ofwhich is seen in Figure 4) aligned withthetransverse bore 105. Acompression spring 108 acts between the inner end of the sleeve 106 and the adjacent end of a locking bolt 108 received therein. The locking bolt 108 has a tapped transverse hole 109 into which is threaded a cross bar 10which emerges to each side of the door panel 101 through respective slots 107 of the sleeve 106 and the adjacent portions of the bore 105.

The locking bolt assembly is held in position by the plate assembly which comprises an inner plate 111 shaped to conform to the recess 103 and fixed therein by screws (not shown), a hole 112 being provided for passage of the locking bolt 108. An outer plate 1 14 covers the inner plate 111 and mountsa spring loaded jaw 115 with an associated detentelement 116. In the position of the jaw 115 illustrated in Figure 4 itcovers a hole 1 forthe locking bolt 108 but when the jaw is closed it clears the hole 117 to permit the locking bolt to extend into locking engagementwith the rear edge of the jaw as seen in the drawing, as will be described in greater detail below.

The jaw 115 is mounted on a pivot 118 which extends through the plate 11 4to the rearthereofwhere it is fixed to a lever 119 the free end of which is connected to a tension spring 120 the other end ofwhich is fixed to an anchorage on the plate (see inset). As also shown in the inset, the detent element 116 is mounted on a stud 121 which is encicled by a compression spring (not shown) urging the detent element 116 into the projecting position shown in Figure 4. The free end of the jaw 115 is shaped to cooperate with the detent element 116 and the latch member that will now be described with reference to Figure 5. The latch member comprises a latch plate 122 fixed to the door jamb 102 and provided with a shaped actuating head 123 having an upper curved surface 124 and an inclined or chamfered sideface 125 interconnecting the front face of the actuating head with a side surface 126 thereof.

The door closure mechanism as so far described operates as follows. When the door is open, the jaw 115 and detent element 116 are in the position illustrated in Figure 4 in which the jaw is held against its spring bias in its open position by the protruding detent element 116. As the free edge of the door panel 101 closes onto the door jamb 102 the curved upper face 1 24ofthe actuating head acts on the free end of the jaw 115 and the chamfered vertical face 125 acts on the detent element 116.The curved upperface 124 relieves the pressure of the jaw 115 on the detent element 116so enabling the detentelementto be pushed inwardly against its spring bias by the chamferedface 125. Inthefinal stages of the closure movement, the jaw 115 engages behind the actuating head and pulls the door panel ontotheframe,the detent element 116 being held in the retracted position by the side face 126 ofthe actuating head. The final part of the closure movement of the door is therefore carried out positively by the action of the jaw 115 moving underthe control of its biasing spring 120. As so far described, the operation is very similar to that of the mechanism described with reference to Figures 1 to 3.However, as the jaw moves to its fully closed position (pivoted to the left in Figure 4) it clears the hole 117 permitting the locking bolt 108 to be extended behind the jaw (as seen in Figure 4) underthe action of its loading spring. The closure mechanism is therefore locked in the closed position until the locking bolt is retracted by the action of a handle orthe like on the cross bar 110 or by an equivalent push button mechanism as will now be described by reference to Figure 4.

Figure 4 shows three devices for retracting the locking bolt 108 by means of a manual operation. At the front of the door panel 4 (as seen in the drawing) is a twist handle 128, at the rear a rocker plate assembly 129 and, as an alternative to both ofthese, a push button 130. The handle 128 is mounted eccentrically of the bore 105 and is provided at its inner end (see inset) with a spring biased lever 131 which engages the locking bolt 108 (shown as a circle in dotted line). Twisting ofthe handlethereforecausesthe leverto turn against its spring bias so as to retract the locking bolt 108.

The rocker plate mechanism 129 comprises a mounting plate 132 with side cheeks 134 mounting a pivot pin 135 on which are pivotally mounted side cheeks 136 ofthe rocker plate itself. These side cheeks 136 extend into corresponding openings 137 of slide plate 138 which has a triangularopening 139 registering with a slot 140 through both of which projects the adjacent end of the cross bar 110. Thus if the lower part of the rocking plate is depressed the slide plate 138 will be moved upwards and the upwardly inclined surface of the triangular opening 139 will cam the cross bar 110 rearwardly.On its next op erationthe rockerplatewill movethe slide plate 138 downwardly causing the other inclined side ofthe triangular opening 139 to effect a similarcaming action. It will be appreciated that a handle 128 may be provided at both sides ofthe door panel 101 if des ired.Alternatively,the rocker mechanism 129 may be provided at both sides ofthe door panel 101. Asa further alternative, the handle 128 and rocker mechanism 129 may both be replaced by a push button mechanism utilising a slot 143 in the locking bolt 108.

The push button 130 extends through the slot 133 when the cross bar 110 is removed and the locking bolt 108 reversed so that the slot 143 occupies the position previously occupied by the cross bar 110.

When the push button 130 is pushed from either side, one ofthetwo inclined surfacesthereofthat form a V-shaped recess therein engages a rounded end oftheslot 143 (see inset) so retracting the locking bolt 108 (in use the V-shaped recess will of course be facing in the opposite direction corresponding to the reversed position of the locking bolt 108).

Following a manual retraction ofthe locking bolt 108 using one of the mechanisms just described or an alternative device the door panel can simply be pulled open causing the jaw 11 5to ride over the actuating head into the open position in which it is then held as soon as the detent element 116 is released by the side surface 126 of the actuating head. The jaw and detent element are thus re-set into the position shown in Figure4in readinessforthe next closure operation.

Claims

1. Adoorclosure mechanism comprising springloaded pulling means adapted to be mounted on one ofthe door panel and frame, and a latch member adapted to be mounted on the other of the door panel and framefor engagement by said pulling means so as to assist in the final stage of door closure, the arrangement being such that withdrawal of the latch member on opening of the door resets the spring-loaded pulling means for the next closure operation.

2. A mechanism as claimed in claim 1 wherein the spring-loaded pulling means has at least one jaw and the latch member is adapted on engagement with the pulling means to initiate pulling movement ofthejaw.

3. Amechanismasclaimed inclaim2wherein the spring-loaded pulling means comprises a pair of jaw biased towards a closed position, and a trigger means associated with retaining means for holding the jaws in an open position, said trigger being adapted to interact with the latch member in the final part of the closure movement of the door to effect move mentoftheretaining means to allow said jaws to move to the closed position.

4. A mechanism as claimed in any one of claims 1 to 3wherein the latch memberisastudadaptedto perform said resetting and initiating operations.

5. A mechanism as claimed in claim 1 wherein a separately operable locking element is utilised to lockthespring loaded pulling means in the closed position thereof in which it engages with the latch member.

6. Amechanism asclaimed inclaim5wherein detent means are provided to retain the springloaded pulling means in a first position obscuring an aperture through which the locking element must pass on its movement to the locking position, and said detent means are movable by the latch member to allow the pulling means to be spring biased to a second position at which it engages the latch member and opens the aperture to passage of the locking element.

7. A mechanism as claimed in claim 6wherein the locking element is spring biased to its locking position.

8. A mechanism as claimed in claim 6 or 7 wherein the detent means are biased to the position atwhich it retains the pulling means in its first position.

9. A mechanism as claimed in any one of claims 6 to 8wherein the pulling means and the detent means are mounted on a plate in which said aperture is provided.

10. A mechanism as claimed in any one of claims 6 to 9 wherein the latch member has an actuating head with an upper curved surface behind which the pulling memberwill locate, and a camming surface for effecting movement of the detent means.

11. A mechanism as claimed in anyone of claims 5to 10 wherein the locking element is manually retractable from its locking position.

12. A door closure mechanism substantially as hereinbefore described with reference to Figures 1 to 3 or Figures 4 and 5 of the accompanying drawings.