AU601202B2 - Strike assembly - Google Patents

Description

"STRIKE ASSEMBLY"

This invention relates generally to security locks and is concerned in particular with the strike components of such locks.

It is known to provide a security lock strike assembly having a rotatably mounted keeper and an electrical latch device engagable with the keeper to hold it in a bolt retention position. On deactivation of the latch device the keeper is rotatable against a coil spring so that the doorway may be opened by simply pushing on the door. In one arrangement, disclosed in Australian Patent 426,174, the latch device comprises an elongate metal arm housed in the wall cavity and held in its keeper locking position by an energized solenoid. In another known commercial construction, the latch device is rendered more compact by forming it as a pivotable catch held in locking engagement with a stop on the keeper by means of a solenoid-responsive finger housed under the keeper and latch.

It will be appreciated that security strike assemblies of the kind discussed can be readily released, by withdrawal of electrical power, in the event of a fire or other emergency and yet be otherwise positively locked against unauthorized passage in either direction through the door.

A limitation on the application of prior arrangements is the throw of the lock bolt. The rotatable keeper must always be configured so that the assembly of keeper and bolt, which is typically of rectangular section, does not seize as the keeper rotates. To prevent seizure occurring, the keeper must be shaped to accommodate the bolt as it turns but this shaping tends to reduce the engagement interface between the two and thus the degree of security. It is therefore an object of the invention to provide a strike assembly of the type having a rotatably mounted keeper which is adaptable to long-throw bolts such as those employed in prisons and like institutions.

It is a secondary object of the invention to provide an improved positive locking between the keeper and its associated latch means. It is a still further secondary object of the invention to provide a strike assembly in which access is allowable by the application of electrical power, so that one is not reliant upon the maintenance of such power to prevent entry through the doorway in which the assembly is mounted. A security arrangement fulfilling this object is normally considered essential for an assembly to be used in prisons and like institutions.

In on& aspect, the invention accordingly provides a strike assembly comprising: a- housing adapted for mounting in a door jamb; an exposed keeper formed by plural keeper elements having opposed recesses which co-ope.rate in a bolt retention condition of the keeper to define a cavity for a lockbolt, which keeper elements are mounted in the housing for rotational movement, on respective axes parallel to the direction of movement of the bolt in and out of said cavity, between said bolt retention condition and a bolt release condition; and releasable latch means supported in said housing having an operative condition in which it engages the keeper elements and so prevents said rotational movement from the bolt retention condition.

There may further include means to place the latch means in said operative condition, for example means such as one or more springs biasing the locking element to its operative condition.

The keeper elements preferably include bolt restraint faces which abut edge to edge in said bolt retention condition and are located on the side towards which the keeper elements move when executing said rotational movement. Wall portions opposite said bolt restraint faces are then dimensioned so as to be spaced apart in the bolt retention condition whereby they do not come into contact when the keeper elements execute said rotational movement. To prevent geometric locking of the lockbolt in the keeper as it rotates while maintaining a firm engagement at the bolt retention condition, each keeper element is formed with a convex internal face on each of these wall portions. The keeper elements are typically configured to co-operatively define a cavity for a rectangular lockbolt.

The latch means may include a single locking bar which is movable in a direction parallel to said axes to engage registrable slots on both keeper elements and on respective shafts or posts on which the keeper elements are respectively rotatably mounted.

Alternatively, the latch means may comprise respective locking elements slidable transversely with respect to said axes, in a slot provided in structure within said housing, to engage respective side grooves in the keeper elements.

Each locking element is then preferably associated with a releasable catch to maintain it in said operative condition, and wherein said groove in the keeper element has inclined sides whereby, orw release of the catch, torsional spring means biases the keeper element to force the locking element out of the groove and to thereby rotate to said bolt release condition.

The assembly may further include step means to define the bolt release condition of each keeper element and thereby prevent excessive rotation of the keeper element, the keeper element rotating through less than 90° between its bolt retention and bolt release conditions.

In a second aspect, the invention further provides a strike assembly comprising; a housing adapted for mounting in a door jamb; an exposed keeper element mounted in the housing for rotational movement between a bolt retention condition and a bolt release condition; latch means supported in said housing including a locking element movable to and from an operative condition in which it engages respective abutments on the keeper element and on structure fixed with respect to the housing, whereby to prevent said rotational movement of the keeper element from its bolt retention condition; and means to place the latch means in said operative condition.

The latch means may be advantageously released from said operative condition by electrically actuable means comprising e.g. one or more solenoids arranged for activation to release the latch means so that it may move from said operative condition against the b'iasing means.

Such electrically actuable means may be associated with means which is responsive to correct location of the lock bolt in the keeper to de-activate the electrically actuable means and so allow return of the latch means to said operative condition, but which otherwise prevents de-activation of the electrically actuable means.

The second aspect of the invention may be conveniently applied to the first in an arrangement in which said locking element is a single element engagable with abutments on the respective keeper elements. The locking element may be a single locking bar which is movable in a direction parallel to said axes to engage registrable slots on both keeper elements and on respective shafts or posts on which the keeper elements are respectively rotatably mounted.

The invention will be further described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a front isometric view of a first embodiment of a strike assembly in accordance with the invention, shown with its keeper in the bolt retention condition;

Figure 2 is a view similar to Figure 1 but showing the keeper in the bolt release condition;

Figure 3 is an exploded isometric view from the rear of the assembly as seen in Figure 1; Figure 4 is a half section, on a plane containing the axes of the keeper elements, of a second embodiment of strike assembly in accordance with the invention, having a similar keeper assembly.to the first embodiment but a different latch means; Figure 5 is a cross-section on the line 5-5 in

Figure 4;

Figure 6 is an exploded isometric view of the principal operative components of the assembly half-seen in Figures 4 and 5; and Figure 7 an exploded view of an optional additional feature for the second embodiment of Figures 4 to 6.

The strike assembly 10 illustrated in Figures 1 to 3 includes an elongate metal housing 12 with an integral front facing plate 13, a rear cover 14 for the housing, a keeper assembly 16 formed by a pair of rotatably mounted exposed keeper elements 16a, 16b in register with a front lockbolt receiving opening 18 in facing plate 13, and latch means indicated generally at 20.

Housing 12 is intended to be mounted in a suitably 5 formed recess in the jamb of a doorway and held in place by means of screws fitted through apertures 22 in facing plate 13. Bolt receiving opening 18 essentially comprises a rectangular cut-out from a vertical side edge of plate 13 , which edge is at the side of the

10 doorway to which the doorleaf is intended to open. At this same side, the outside of the assembly, the main body of housing 12 is open between a pair of parallel laterally protruding ledges 26a, 26b which, as will be seen in due course, define limit stops for the

15rotational motion of the keeper elements.

At the other side, the housing is closed by a side wall 28 which is offset inwardly to define a land 29 co-planar with and extending rearwardly from the inside upright edge of opening 18. Above and below ledges 26a,

2026b, housing 12 defines opposed U-section compartments 30a, 30b in which, as will be seen, respective solenoid components of latch means 20 are housed. The upper compartment 30b is extended to form a closed box 32 for electrical circuitry. Box 32 is accessible by way of a

25removable cover panel 34 on the inside of the box and includes respective apertures 36a, 36b to admit electrical leads.

Cover 14 is detachably fastened to housing 12 by a pair of screws 11 which extend through apertures 15a,

3015b in the housing adjacent compartments 30a, 30b and through matching apertures in tabs 14a on the cover. The cover provides a rear upright ledge 26c which registers with ledges 26a, 26b.

Projecting rearwardly from the reverse face of facing plate 13 just above and below opening 18 are a pair of posts 38a, 38b which provide hinge pins on which the keeper elements 16a, 16b are respectively mounted for rotational movement, on respective axes 17a, 17b (Figure 3) , between a bolt retention condition (Figures 1 and 3) and a bolt release condition (Figure 2) . Each post includes a slightly broader base portion 40 on which the keeper elements are actually mounted, with an interposed split bush 42, and a relatively narrower outer portion 44 which includes a diametral slot 46 extending for most of its length from the tip of the post. Slots 46 are a component of latch means 20.

Keeper elements 16a, 16b may comprise unitary metal casings of substantial thickness^". They are almost identical and each consists essentially of a broad body portion 48, which is rotatably received on the base portion 40 of a respective post 38a or 38b, and an assembly 50 of wall portions which define a channel recess 52 closed at the rear of the keeper element. In the bolt retention condition of the keeper the two recesses 52 are opposed and in register and thereby co-operate to define a cavity 53 for a long-throw rectangular-section lockbolt. Axes 17a, 17b are parallel to the direction of movement of the bolt in and out of cavity 53. Wall portions 50 include outer bolt restraint faces 54 that abut edge-to-edge in the bolt retention condition, keying together (Figure I) by virtue of co-operative tongue and groove formations 56 at their interface. The keeper elements further include inner wall portions 58 opposite restraint faces 54 which are separated and inwardly convex. The separation prevents the keeper elements from contacting as they rotate to the bolt release condition and the convexity precludes geometric locking between the keeper 5 elements and the lockbolt. The bolt cavity 53 is defined between wall portions 58 by land 29.

The bolt release condition of the keeper is determined fe contact of the keeper elements with ledges 26a, 26b (Figure 2) . The bolt retention condition is 10 further strengthened by contact of curved shoulders 55 with the outer corners of opening 18 (Figure 1) .

Keeper elements 16a, 16b are in fact biased to the bolt release condition by a pair of torsion springs 60 mounted on bush 42 within a counter bore in the 15 respective elements. However, latch means 20 is provided to maintain the bolt engagement position except when the latch means^' is positively released by external intervention. The key effective element of the latch means 20 is an elongate, square-section locking bar 62 20 which extends between and seats in slots 46 in posts 38a, 38b and in registering diametral slots 66 in respective bosses 64a, 64b integrally formed on the body portions 48 of keeper elements 16a, 16b. When cover 14 is in place, locking bar 62 is biased to this operative 25 condition by a pair of helical compression springs 65 retained on posts 38a, 38b against the inside of cover 14.

The release mechanism for the latch means is electrically operable and comprises a pair of solenoids 3068a, 68b, already adverted to, housed within compartments 30a, 30b. Armatures 70 of these solenoids engage respective straps or tabs 72 which are slidably but rotationally carried by posts 38a, 38b as shown, between locking bar 62 and the respective springs 65. These tabs are fastened to bar 62 by means of central screws at 74.

The arrangement of the solenoids is such that their activation by electrical current drives armatures 70 rearwardly against tabs 62 and thereby lifts tabs 72 and moves bar 62 out of slots 66 (but still within slots 46) , against springs 65. Torsional springs 60 will bias the keeper elements rotatably outwardly to release the lockbolt.

An alternative embodiment of latch means 20' is depicted in Figures 4 and 5, in which like parts are indicated by like reference numerals. In this embodiment, a separate solid locking element 62' is associated with^' each keeper element 16a', 16b' and is held in its operative condition by a respective pivotable catch 80 triggered in turn by a solenoid 68a' , 68b'.

Figures 4 and 5 show only one of these mirror image arrangements. Keeper elements 16a' and 16b' include respective solid pins 116, 117 with end bosses 64' journalled in a front plate 114 behind cover 13' and in an intermediate rear plate 118. Locking element 62' is slidable inwardly and outwardly of a close-fitting vertical slot 82 defined in a generally U-section holder 84 held by multiple pins 85.

Element 62' is of axial length equal to that of the body of keeper elements 16a' , 16b' and consists of a flanged cage 63 and a hardened steel dowel 63b held between the flanges 63a of the cage 63 so as to define a curved forward edge of the locking element. Element 62' is biased outwardly of slot 82 by a pair of light helical compression springs 65' mounted in opposed blind bores 86, 87 in element 62' and holder 84. Locking element 62' engages into either of two longitudinal indexing grooves 88, 89 in the back surface of keeper element 16a' . Deeper groove 88 defines the bolt retention position and shallower groove 89 the bolt release position (broken lines in Figure 5) . An outstanding rib 91 on each keeper element 16a' , 16b' near groove 89 is arranged to abut an inclined complementary end face 84a of holder 84 (as indicated by broken lines in Figure 5) thereby determining the maximum open position of the keeper elements.

Catch 80 is hinged at 90 in holder 84 behind slot 82 within a transverse slit 92 in the holder. The catch has three arms. A forward arm 80a extends, with horizontal and ertical clearance, into a notch 94 in the rear of locking element 62' and has an orthogonal seat 96 for the upper edge 95 of notch 94. A rearward catch arm 80b is braced by a heavy helical compression spring 98 to rotatably bias catch 80 so that seat 96 normally positively engages edge 95. A long depending forked arm 80c extends through a slot 81 in the end of rear plate 118 and snugly locates between shoulders 101 and a pin 99 on an end adaptor 102 fitted to the armature 70' of solenoid 68a' , which is mounted to the rear face of plate 118. Activation of solenoid 68a' by application of electrical power moves armature 70" to rotate catch 80 against spring 98, thus dissengaging seat 96 from notch edge 95. The clearance in notch 94 is sufficient vertically for this disengaging to occur and sufficient horizontally for the locking element to move back as torsion springs 60' rotate keeper element 16a'. The forward vertical edge of element 62' is rounded and grooves 88, 89 correspondingly cambered, and springs 60', 65' suitably balanced, so that springs 60' can cause keeper element 16a' to lift locking element 62' against springs 65 ' . The keeper element is rotated open by springs 60* until rib 91 strikes face 84a of holder 84.

It will be appreciated that in this second embodiment, the side walls of groove 88 and slot 82 constitute respective abutments engaged by locking element 62' to prevent rotational movement of the keeper element when seat 96 is engaging notch edge 95. It will also be noted that the keeper element is of cross-section slightly different from the first embodiment in that wall portions 58' (Figure 5) exhibit a wholly rounded (180°) outer edge 58a.

When the solenoid is de-activated, and the door closed, the re-entering lockbolt will push against edges 58a to dislodge element 62' from groove 89 and so return the keeper elements to the bolt retention position, in which spring 98 ensures re-engagement of notch edge 95 in seat 96. Groove 89 is configured to facilitate such action while preventing inadvertent automatic relocking of the assembly without the bolt in the keeper. Moreover, the angled location of the keeper elements at less than 90°, as evident from Figure 5 (and also from Figure 2 for the first embodiment) , also facilitates the keeper closing action of the lockbolt. Further excessive opening of the keeper elements is of course prevented by abutment of rib 91 with face 84a of holder 84. Such a self-closing and locking facility is valuable for institutional application of the invention, as is the "fail secure" arrangement by which the door is not dependent on electrical power to remain locked.

Figure 6 shows some additional subsidiary features not shown in Figures 4 and 5. Microswitches 110 responsive to movement of the forked arms 80c of catches 80 monitor releasing operation of solenoids 68a', 68b'. A further microswitch 112 on the side of one of the holders 82 is responsive to removal of the cover 114, which abuts the outer surface of holder. Each microswitch is wired to activate an alarm or other warning device at a remote monitoring station.

The particular advantage of the illustrated forms of strike assembly is the ability to apply the assembly to locks with a long-throw rectangular bolt without risk of seizure of the bolt in the keeper when the latter rotates. The problem of latching a two-part keeper is met in a very neat and effective manner which is also highly positive in that it entails a coupling of abutment surfaces on the keeper elements and on the housing. A further feature of the particular latch means is that it is normally engaged to lock the door but is easily and simply released by application of electrical current to a pair of solenoids. Figure 7 depicts an optional additional feature for the embodiment of Figures 4 to 6 , viz a switch assembly for preventing locking of the keeper unless the lockbolt is correctly located therein. A hollow body 120 is secured by pins between plates 114, 118 in the space between the short rounded-end wall portions 58' of 5 keeper elements 16a', 16b', as shown by dot-dash lines at 122 in Figure 5. A spring-loaded, hollow, segmental switch lever 124 is pivoted at 126 in a recess 128 of body 120 so to be rotatable from an outwardly projecting position (that shown in Figure 7) to and a recessed

10position in which it triggers a microswitch 129. On entry of the bolt, the front edge strikes the curved surface 125 of lever 124, rotating the lever inwardly against a torsional spring 130 to trigger the switch. Switch 129 is arranged in circuit so that the keeper

15elements cannot be locked (i.e. solenoid power withdrawn) -until the switch is activated by lever 124.

To prevent unauthorized locking'of the door, lever 124 can be locked in its outward position by a beak latch 132 which locates in the hollow inturned lever

20124. Latch 132 is held in this position by a third solenoid 134 which is mounted with its axis horizontal in the space between the two primary solenoids 68a' , 68b'. The armature 135 of solenoid 134 abuts a lever 136 that unlies and bears against the bottom of latch

25132. Latch 132 and lever 136 are hinged at 133, 137 respectively. When solenoid 134 is not activated, lever 136 is not restrained and latch 132 is rotated by a torsional spring 138 to release switch lever 124.

30

Claims (24)

CLAIMS :

1. A strike assembly comprising: a housing adapted for mounting in a door jamb; an exposed keeper formed by plural keeper elements having opposed recesses which co-operate in a bolt retention condition of the keeper to define a cavity for a lockbolt, which keeper elements are mounted in the housing for rotational movement, on respective axes parallel to the direction of movement of the bolt in and out of said cavity, between said bolt retention condition and a bolt release condition; and releasable latch means supported in said housing having an operative condition in which it engages the keeper elements and so prevents said rotational movement from the bolt retention condition^*.

2. A strike assembly according to claim 1 wherein said keeper elements include respective bolt restraint faces which abut edge to edge in said bolt retention condition and are located on the side towards which the keeper elements move when executing said rotational movement.

3. A strike assembly according to claim 2 wherein to prevent geometric locking of the lock bolt in the keeper as it rotates while maintaining a firm engagement at the bolt retention condition, each keeper element is formed with a convex internal face opposite said bolt restraint face.

4. A strike assembly according to any preceding claim wherein the keeper elements are configured to co-operatively define a cavity for a rectangular lockbolt.

5. A strike assembly according to any preceding claim further comprising means to bias the latch means to said operative condition.

6. A strike assembly according to claim 5 further comprising means electrically actuable to release said latch means so that it may move from said operative condition against said biasing means.

7. A strike assembly according to claim 6 further comprising means which is responsive to correct location of the lock bolt in the keeper to de-activate the electrically actuable means and so allow return of the latch means to said operative condition, but which otherwise prevents de-activation of the electrically actuable means.

8. A strike assembly according to any preceding claim wherein said latch means includes a single locking bar which is movable in a direction parallel to said axes to engage registrable slots on both keeper elements and on respective shafts or posts on which the keeper elements are respectively rotatably mounted.

9. A strike assembly according to any one of claims 1 to 7 wherein said latch means comprises respective locking elements slidable transversely with respect to said axes, in a slot provided in structure within said housing, to engage respective side grooves in the keeper elements-.

10. A strike assembly according to claim 9 wherein each locking element is associated with a releasable catch to maintain it in said operative condition, and wherein said groove in the keeper element has inclined sides whereby, on release of the catch, torsional spring means biases the keeper element to force the locking element out of the groove and to thereby rotate to said bolt release condition.

11. A strike assembly according to claim 10 further comprising step means to define the bolt release condition of each keeper element and thereby prevent excessive rotation of the keeper element, the keeper element rotating through less than 90° between its bolt retention and bolt release conditions.

12. A strike assembly according to claim 10 or 11 wherein each said keeper element includes a further groove positioned to receive and thereby engage the locking element at said bolt release condition, which engagement is released by adequate force on the keeper element.

13. A strike assembly according to claim 10, 11 or 12 wherein each releasable catch comprises a pivotable catch which defines a seat for the respective locking element and which is biased by catch biasing means to maintain the locking element in said seat and thereby in said operative condition.

14. A strike assembly according to claim 13 wherein said catch includes an arm in engagement with solenoid means actuable to rotate the catch against said catch biasing means and to thereby release the catch.

15. A strike assembly comprising; a housing adapted for mounting in a door jamb; an exposed keeper element mounted in the housing for rotational movement between a bolt retention condition and a bolt release condition; latch means supported in said housing including a locking element movable to and from an operative condition in which it engages respective abutments on the keeper element and on structure fixed with respect to the housing, whereby to prevent said rotational movement of the keeper element from its bolt retention condition; and means to place the latch means in said operative condition.

16. A strike assembly according to claim 15 further comprising means to bias the latch means to said operative condition.

17. A strike assembly according to claim 16 further comprising means electrically actuable to release said latch means so that it may move from said operative condition against said biasing means.

18. A strike assembly according to claim 17 further comprising means which is responsive to correct location of the lock bolt in the keeper to de-activate the electrically actuable means and so allow return of the latch means to said operative condition, but which otherwise prevents de-activation of the electrically actuable means.

19. A strike assembly according to any one of claims 15 to 18 wherein said latch means comprises a locking element slidable transversely with respect to the axis of said rotational movement, in a slot in said structure, to engage a side groove in the keeper element.

20. A strike assembly according to claim 19 wherein each locking element is associated with a releasable catch to maintain it in said operative condition, and wherein said groove in the keeper element has inclined sides whereby, on release of the catch, torsional spring means biases the keeper element to force the locking element out of the groove and to thereby rotate to said bolt release condition.

21. A strike assembly according to claim 20 further comprising step means to define the bolt release condition of the keeper element and thereby prevent excessive rotation of the keeper element, the keeper element rotating through less than 90° between its bolt retention and bolt release conditions.

22. A strike assembly according to claim 20 or 21 wherein said keeper element includes a further groove positioned to receive and thereby engage the locking element at said bolt release condition, which engagement is released by adequate force on the keeper element.

23. A strike assembly according to claim 20, 21 or 22 wherein said releasable catch comprises a pivotable catch which defines a seat for said locking element and which is biased by catch biasing means to maintain the locking element in said seat and thereby in said operative condition.

24. A strike assembly according to claim 23 wher.ein said catch includes an arm in engagement with solenoid means actuable to rotate the catch against said catch biasing means and to thereby release the catch.