GB2119007A - Locking devices for fitting to latch mechanisms - Google Patents

Abstract

A locking device is adapted for attachment to a pre-assembled latch mechanism composed of a casing 10, a latch bolt 13 which is movable between extended and retracted positions with respect to the casing, and a manually operable handle 16 which is operatively connected to the bolt 13 by means of a rotatable spindle 15. The locking device comprises a cam member 43 mounted on the spindle 15 externally of the casing 10 for rotation with the handle, operating linkages 47 mounted externally of the casing 10 and operatively connected to the cam member 43, via 40 and 44, and dead bolts 49 which are extendable and retractable by movement of the operating linkages 47. Lobes 41, 42 on the cam member 43 provide lost motion between the cam member and the operating linkages 47. <IMAGE>

Description

SPECIFICATION Locking devices for fitting to doors or other closures This invention relates to locking devices for fitting to doors or other closure members.

Conventional locking devices for closure members comprise a latch bolt which can be extended and retracted by means of a manually operable handle, and a dead bolt which can be extended and retracted by means of a keyoperated mechanism. Such locking devices are usually positioned approximately mid-way up the closure member, and often the security provided by such an arrangement is insufficient because the closure member can be prised open at its top or bottom. To overcome this problem, a locking device has recently been developed wherein additional dead bolts at the top and bottom of the closure member can be extended by a special operation of the manually operable handle, thereby avoiding the need to provide separate locking devices (such as manually operable bolts) on these parts of the closure member.An example of this type of locking device is disclosed in UK Patent specification No. 2051214A. Such a construction is highly advantageous since it enables all of the locking and latch functions of the device to be controlled from a single point on the closure member. However, the complexity of the mechanisms involved make the overall locking device expensive to manufacture, and few components of existing conventional locking devices can be employed to economise on these expenses.

It is an object of a first aspect of the present invention to provide a locking device of this general type which can simply be attached to an existing latch mechanism.

In its said first aspect, the present invention provides a locking device adapted for attachment to a pre-assembled latch mechanism composed of a casing, a latch bolt which is movable between extended and retracted positions with respect to the casing, and a manually operable handle which is operatively connected to the bolt by means of a rotatable spindle, the locking device comprising a cam member mounted on the spindle externally of the casing for rotation with the handle, at least one operating linkage mounted externally of the casing and operatively connected to the cam member, at least one dead bolt which is extendable and retractable by movement of the operating linkage or operating linkages, and means providing lost motion between the cam member and the operating linkage or operating linkages.

Preferably, the locking device includes two such dead bolts and two such linkages for operating the dead bolts respectively, the operating linkages extending in opposite directions from the casing and being arranged to move in opposite directions upon rotation of the cam member in a single direction. Desirably, the cam member is operatively connected to only one of the operating linkages, and the two linkages are operatively interconnected by means of a separate coupling member. Conveniently, the coupling member is disposed around the spindle and is freely rotatable relative thereto: the coupling member may for example be in the form of a gear wheel which is meshed on opposite sides thereof with rack teeth on the operating linkages, respectively.In the latter case, the operating linkages can include respective plates disposed in face-to-face relation on an external surface of said casing and defining therebetween an opening within which the gear wheel is disposed, the rack teeth being provided on an edge of each plate which faces into the opening.

Advantageously, said means providing lost motion is formed by a pair of angularly spaced lobes on the cam member which are selectively engageable with an abutment on the operating linkage or, where two such linkages are provided, on at least one of the operating linkages.

In a preferred construction, the or each operating linkage includes an element (such as the above-mentioned plate) operatively coupled to the cam member and a link connected at one end thereof to the element, the opposite end of the link being disposed slightly behind a plane which includes a front face of said casing.

In the locking device dislosed in the abovementioned UK Patent Specification No.

201 5214A, retraction and extension of the latch bolt is effected in a conventional manner by moving the handle between first and second positions, the handle being biassed into its first position wherein the latch bolt is extended. When it is desired to extend the additional dead bolts, the handle is moved from its first position to a third position, the latter lying in the opposite direction to the second position with respect to the first position. Upon release of the handle, the latter returns to its first position but the additional dead bolts remain extended. Retraction of the additional dead bolts is accomplished by moving the handle from its first to its second position which action also serves to retract the latch bolt.

In order to achieve such operation, it is necessary to provide a lost motion on the one hand between the handle and the latch bolt (so that the latter is not operated when the handle is moved so as to extend the additional dead bolts), and on the other hand between the handle and the additional dead bolts (so that the handle can return to its first position without retracting the dead bolts after the latter have been extended). In the construction disclosed in the aforesaid UK Patent Specification No. 201 521 4A, the lost motion between the handle and the latch bolt is provided by a cam member which rotates at all times with the handle. The cam member engages the latch bolt when the handle is moved between its first and second positions but becomes disengaged therefrom when the handle is moved to its third position.Although this construction works perfectly well, it requires a complicated arrangement of springs on the one hand to bias the handle into its first position from both directions, and on the other hand to bias the latch bolt into its extended position. The need to provide such springs increases the bulk of the locking device to a degree which is unacceptable where the device is to be attached to an existing latch mechanism in the manner described above.

It is an object of a second aspect of the present invention to provide lost motion between the handle and the latch bolt in a more convenient manner.

According to the said second aspect of the invention, a locking device for a closure member comprises a manually operable handle biassed into a first position and movable from said first position in one direction into a second position and in the opposite direction into a third position, the latch bolt which is extended and retracted with respect to the closure member by movement of the handle between said first and second positions, a dead bolt which is extended with respect to the closure member by movement of the handle from said first position to said third position and which is subsequently retracted with respect to the closure member by movement of the handle from said first to said second position, a spindle which is rotated by movement of the handle, a rotatable operating element mounted on the spindle and operatively engaged with the latch bolt, and means providing lost motion between the spindle and the operating element.

The means providing lost motion is preferably formed by a pair of abutments on the spindle and on the operating element respectively, the abutments being mutually engaged during movement of the handle between said first and second positions but being disengaged by movement of the handle from said first position to said third position. Where the spindle passes through a bore in the operating element, the abutments are desirably provided on the external surface of the spindle and on the internal surface of said bore, respectively. A further pair of abutments can be provided on the spindle and on the operating element respectively, which abutments are mutually engaged when the handle is in said third position.

In a preferred construction, the spindle is of square cross-section and a portion thereof which passes through the bore in the operating element has at least one corner of said square crosssection removed, and said bore is generally of circular cross-section and has at least one flat on its internal surface which is selectively engageable by faces of the spindle adjacent to said removed corner or a respective one of said removed corners. Most preferably, two diagonally opposed corners of the spindle cross-section are removed, and the internal surface of the bore has two flats at diametrically opposed positions thereon.

Desirably, the handle is rotatably supported on a support member, a cam member is capable of limited angular movement with respect to both the handle and the support member such that during movement of the handle between its first and second positions the cam member remains stationary relative to the support member and the handle rotates relative thereto, and during movement of the handle between its first and third positions the cam member rotates with the handle relative to the support member, and the handle is biassed into said first position by a first, spring acting on the operating element and opposing movement of the handle from said first position to said second position, and a second spring acting on the cam member and opposing movement of the handle from said first position to said third position.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view of a locking mechanism for a door or other closure member, the locking mechanism including a conventional lock and a locking device according to the present invention; Figure 2 is a side view of the conventional lock; Figures 3 and 4 are sectional side views of a cam of the conventional lock and a rotatable spindle, the spindle being shown respectively in two different positions; Figure 5 is an end view of part of the locking mechanism shown in Figure 1; Figure 6 is a view in the direction of arrow VI in the Figure 5, with parts of the aforesaid locking device removed for the sake of clarity; Figures 7 and 8 are, respectively, side views of two plates which form part of the locking device;; Figure 9 is a longitudinal view of the aforesaid spindle and a cam mounted thereon; Figure 10 is a side view of parts of the locking device which were removed from Figure 6; Figure 11 is a side view of a handle mechanism which forms part of the locking mechanism shown in Figure 1; Figure 12 is a plan view of a cam which forms part of the handle mechanism; Figures 13 and 14 illustrate the operation of the cam shown in Figure 12; Figure 1 5 is a schematic side view of another embodiment of a locking device according to the present invention; Figure 1 6 is a schematic side view of a further embodiment of a locking device according to the present invention; and Figures 1 7 to 1 9 are views of various components which can be used in conjunction with the locking device shown in Figure 16.

The locking mechanism shown in Figure 1 is composed of a generally conventional lock to which is attached a locking device, to be described in detail later. The conventional lock, which may for example be of the type described in our co-pending UK Patent Application No.

2101 668A, is shown in detail in Figure 2 and comprises a casing 10 which is mortised into an edge of a door or other closure member, indicated in broken line at 1 The casing 10 is composed of a generally tray-shaped body (not visible in the drawings) having an open side which is closed by a top cover 12. A latch bolt 13 is mounted in the casing 10 for sliding movement relative thereto between an extended position (as shown) and a retracted position and is biassed into its extended position by a spring (not illustrated).The latch bolt 1 3 is operatively engaged by a rotatable cam 14 (see Figures 3 and 4) mounted on a squaresection spindle 15, the spindle in turn being received in a square-section recess in a handle 1 6 so that the latch bolt 13 can be extended and retracted by suitable operation of the handle in a conventional manner.

A dead bolt 1 7 is also mounted in the casing 10 for movement relative thereto between an extended position (as shown in Figure 2) and a retracted position. A pin 18, the purpose of which will be explained later, extends through elongate slots 1 9 in the casing body and the top cover 12 and moves along these slots as the dead bolt 1 7 is extended and retracted. Extension and retraction of the dead bolt is effected by suitable operation of a key-operated lock unit 20 received through suitably profiled apertures 21 in the casing body and the top cover 12. In the illustrated arrangement, the lock unit 20 is of the so-called dual profile type: however, a lock unit of the oval type may equally well be employed.

Although two slots 19 and two apertures 21 are provided in the casing body and the top cover 12 respectively, only one of each (i.e. that provided in the top cover) is actually shown in the drawings.

The latch bolt 13 and the dead bolt 17 when extended pass through respective openings 22 and 23 in a front face 24 of the casing 10 (see Figure 5). The opening 22 is configured so as to allow the orientation of the latch bolt 13 to be reversed in the manner described in detail in UK Patent Application No. 2093904A, so that the hand of the lock may be set as desired. More particularly, the opening 22 has a generally rectangular portion 25 through which a chamfered tongue 26 of the latch bolt 13 passes, and a pair of larger slot portions 27 which can selectively receive a backing flange 28 at the rear of the chamfered tongue 26, the particular slot portion 27 in which the backing flange 28 is received being dependent upon the orientation of the latch bolt 13.A rectangular opening 29 (see Figure 2) in the top cover 12 of the casing 10 enables access to be gained to a catch (not shown) which, when operated, permits the bolt orientation to be changed. Also extending onto the front face 24 of the casing is a member 30 which can be manually twisted to provide night latch operation of the bolt 13, i.e. to retain the bolt 13 in its retracted position against the action of its biasing spring.

The above-mentioned locking device which is attached to the conventional lock is shown in detail in Figure 6. The locking device includes a pair of plates 31 and 32 (shown in detail in Figures 7 and 8 respectively) which are disposed in face-to-face relation against an outer surface of the top cover 12, so that the plates are slidable both relative to each other and relative to the casing 10. The plates are guided in this sliding movement by means of a pair of spacer bushes 33 on the exterior of the top cover 12 which slidably engage respective slots 34 in each plate.

In addition the plate 32, which is the closer of the two plates to the top cover 12, carries a bearing pin 35 which bears against the top cover during the aforesaid sliding movement.

The aforementioned cam 14 of the conventional lock has an axial extension 36 (see Figures 3 and 4) which projects outwardly from the top cover 12 of the casing 10, and a gear wheel 37 is mounted on the extension 36 so as to be freely rotatable with respect to the cam 14.

The gear wheel 37 is received in an opening 38 formed in the plate 32, and is engaged on opposite sides by rack teeth 39 provided on edges of the plates 31 and 32 respectively which face into the opening. A pin 40 upstanding from the plate 31 is disposed in the path of movement of a pair of lobes 41 and 42 on a cam 43 (see Figures 9 and 10) which is keyed to the spindle 1 5 for rotation therewith. As will be explained in greater detail later, rotation of the cam 43 causes its lobes to engage with the pin 40 and thereby move the plate 31 upwardly or downwardly (as viewed in Figure 6) relative to the casing. Such movement of the plate 31 is transmitted to the plate 32 through the gear wheel 37, so that downward movement of the plate 31 causes upward movement of the plate 32 and vice versa.

Each of the plates 31 and 32 has connected thereto one end of a respective curved link arm 44, the opposite end of the arm being bent over to form a flange 45 which lies just behind a plane containing the front face 24 of the casing 10.

Secured to the flange 45 of each arm 44 inter alia by means of a nut 46 fixed thereto is one end of a respective operating bar 47 (see Figure 1). At the opposite end of each bar 47 there is provided a casing 48 housing a dead bolt 49, the latter being extended and retracted relative to the casing 48 by means of upward and downward movement of the operating bars 47. Like the casing 10, the two casings 48 are mortised into the edge of the closure member. A spring 50, shown in Figure 6, connected between a lug 51 on the plate 31 and a lug 52 fixed to the top cover 12 of the casing 10 biasses the mechanism into the position depicted in that Figure, wherein the dead bolts 49 are retracted into their respective casings 48.

The locking mechanism described above operates as follows. Normally, the handle 1 6 is biassed into a generally horizontal position as depicted in solid line in Figure 11. In order to retract the latch bolt 13, the handle 16 is simply depressed through an angle of approximately 450 to the position indicated in broken lines at 16' in Figure 11. Such movement of the handle 16 causes the spindle 15 and hence the cams 14 and 43 to rotate in a clockwise direction as viewed in the drawings, the cam 1 4 thereby retracting the latch bolt 1 3 against the action of its biassing spring in a conventional manner. At this time, the lobes 41 and 42 on the cam 43 do not contact the pin 40, and hence the locking device attached to the conventional lock remains inoperative.

When it is desired to activate the locking device, the handle 1 6 is lifted from its horizontal position through an angle of approximately 900 to the position indicated in broken line at 16" in Figure 11. Such movement of the handle rotates the cam 43 in an anti-clockwise direction thereby bringing the cam lobe 41 into contact with the pin 40 so as to move the latter downwardly. This in turn causes the plate 31 to move downwardly and the plate 32 to move upwardly, thereby moving the operating bars 47 to extend the dead bolts 49 from their respective casings 48. At this time, no rotation of the cam 14 occurs due to the fact that the lost motion is provided between the cam and the spindle 15, in a manner which will be described later.Upon its release, the handle 1 6 is biassed back to its horizontal position, but the consequential reverse rotation of the cam 43 is insufficient to engage the lobe 42 with the pin 40.

When the mechanism is in the above-stated condition, respective edges 53 and 54 on the plates 31 and 32 respectively clear the slot 19 in the top cover 12 along which the pin 18 moves.

In addition, a short slot 55 in the plate 32 comes into registration with a front end of the aforementioned slot 19. Because movement of the pin 1 8 along the whole length of the slot 1 9 is now unobstracted, the lock unit 20 can be operated to extend the dead bolt 17 from the casing 10. When the bolt 1 7 has been thus extended, the pin 18 engages in the short slot 55 in the plate 32 and thereby locks the latter against movement, ensuring that the two dead bolts 49 cannot be retracted unless the dead bolt 1 7 is first retracted back into the casing 10.

In order to release the locking mechanism, the dead bolt 17 is first retracted by suitably operating the lock unit 20, thereby disengaging the pin 18 from the slot 55 and moving the pin out of the path of movement of the plates 31 and 32. The handle is then depressed into the position 16' shown in Figure 11. This action serves to rotate the cam 43 in a clockwise direction so that the cam lobe 42 moves the pin 40 and hence the plate 31 upwardly. Such upward movement of the plate 31 is converted into downward movement of the plate 32 by the gear wheel 37, so that the two operating bars 47 are moved to retract the bolts 49 back into the casing 48.

Depression of the handle 1 6 also serves to rotate the cam 14 in a clockwise direction so that the latch bolt 13 is retracted in the same action as retracts the dead bolts 49. When the handle 16 is released, it moves back into its horizontal position under the action of its bias, thereby allowing the latch bolt 1 3 to extend from the casing 10. The anticlockwise rotation of the cam 43 which results from such movement of the handle is not, however, sufficient to engage the lobe 41 with the pin 40. The mechanism is thus restored to its starting position.

Referring now to Figures 3, 4 and 9, the abovementioned lost motion between the cam 14 and the spindle 15 is provided as follows. A portion 56 of the spEndre 5 5 Ts specTally configured by machining away two diagonally opposite corners of its square cross-section, while a generally circular bore 57 in the cam 14 which receives the portion 56 is provided with two diametrically opposed flats 58. When the handle 1 6 is in its horizontal position, the portion 56 is oriented relative to the flats 58 in the manner shown in Figure 3. Under this condition, depression of the handle 1 6 causes thrust surfaces 59 on the spindle portion 56 to engage the flats 58 respectively, thereby rotating the cam 14 in the direction of arrow 60.Upon release of the handle, the cam 14 is rotated back to its starting position by a biassing spring (not shown) attached to a pin 61 on the cam 14 and acting in the opposite direction to arrow 60. When the handle 16 is lifted in order to extend the dead bolts 49, the spindle portion 56 is able to rotate within the bore 57 until surfaces 62 thereon come into contact with the flats 58 respectively, as depicted in Figure 4. Such rotation provides a full 900 movement of the handle 1 6 because each pair of adjacent surfaces 59 and 62 on the spindle portion 56 are themselves disposed at 900 to one another. Upon release of the handle 16 from its 900 lifted position, the spindle portion 56 is free to rotate back to the position shown in Figure 3 wherein the thrust surfaces 59 thereon are engaged with the flats 58 respectively.

As can be seen in Figure 11, the handle 16 is rotatably journalled in a back plate 63 which is surface mounted on the closure member. The handle includes a hollow spigot 64 of generally square cross-section within which is received an end of the spindle 1 5. In order to limit the amount by which the handle can be rotated relative to the back plate 63, a cam 65 (shown in detail in Figure 12) is provided which is rotatably mounted on the back plate and which surrounds the spigot 64.

The cam 65 includes a right-angle projection 66 defining a pair of abutment surfaces 67 and 68 which are mutually perpendicular, and is rotatable between a position wherein the abutment surface 67 engages one side wall 69 of a channel in the rear of the back plate 63 (as shown in Figure 13) and a position wherein the abutment surface 68 similarly engages the opposite side wall 70 of the aforesaid channel. Because the abutment surfaces 67 and 68 are mutually disposed at right-angles, it will be manifest that the cam 65 turns through 900 between the two abovementioned positions: this corresponds to movement of the handle 1 6 between its horizontal position and the lifted position 1 6it in Figure 11. A spring 71 is connected between the cam 65 and the back plate 63 and biasses the cam into the position shown in Figure 13: this position of the cam 65 corresponds to the horizontal disposition of the handle 16, and hence the spring 71 acts as a return spring to bias the handle into its horizontal position from the lifted position 16".

In order to allow the handle 1 6 to be depressed into the position 16' shown in Figure 11, lost motion is provided between the cam 65 and the spigot 64. More particularly, a central generally circular aperture 72 in the cam 65 through which the spigot 64 passes is provided with two diametrically opposed, inwardly directed projections 73 each of which presents a pair of abutment surfaces 74 and 75 for engagement with the external periphery of the spigot. As depicted in Figure 13, when the handle 1 6 is in its horizontal disposition the spigot 64 engages the abutment surface 74 on each projection 73.

Consequently, when the handle 1 6 is lifted the spigot 64 causes the cam 65 to rotate in the manner described above. When the handle 1 6 is depressed, however, the spigot 64 is free to rotate in the aperture 72 until it reaches the position shown in Figure 14 wherein it engages the abutment surface 75 on each projection 73.

At this point, further rotation of the spigot 64 and hence the handle 1 6 is prevented on the one hand due to its engagement with the abutment surfaces 75 and on the other hand due to engagement of the abutment surface 67 on the projection 66 with the side wall 69. The angular movement of the handle 1 6 between the conditions indicated in Figures 13 and 14 is approximately 450, being the amount required to retract the latch bolt 1 3 in the manner described previously.Upon release of the handle 1 6 from its depressed position, the handle is returned to its horizontal disposition by the force of the aforementioned spring acting on the cam 14, this force being transmitted to the handle by way of the engaging surfaces 58 and 59 on the cam bore 57 and the spindle portion 56 respectively (see Figure 3).

Referring back to Figure 10, there is shown therein a facing plate 76 which is secured over the top cover 12 of the casing to cover the various components of the locking device. This facing plate is similar in configuration to the top cover 12, and indeed it can be produced using the same tooling with certain of the tool punches which produce the various openings in the cover 12 being withdrawn during production of the plate 76. Accordingly, the plate 76 includes a rectangular opening 77 through which access can be gained (via the opening 29 in the cover 12) to the aforementioned catch whereby the orientation of the latch bolt 1 3 can be reversed, an elongate slot 78 along which the pin 18 slides, and a configurated aperture 79 through which the lock unit 20 is received.Additionally, the plate 76 is formed with a pair of holes 80 through which screws (not shown) are passed for securement to the spacer bushes 33 which guide the two plates 31 and 32 (see Figure 6), and a further hole 81 through which an additional screw is passed for engagement with an internally threaded bore in the lug 52 which provides an anchor point for one end of the spring 50. Further, a slot 82 is formed in the plate 76 and slidably receives therein a top end of the lug 51 which provides an anchor point for the opposite end of the spring 50, thereby assisting guiding of the plate 31.

Also provided on the plate 76 is an elongate slot 83 through which the pin 40 slidably passes.

The pin 40 has an enlarged head (see also Figure 5), and accordingly the slot 83 is broadened out at one end thereof to permit the head to be passed therethrough during assembly of the lock mechanism. Such engagement of the pin 40 in the slot 83 assists guiding of the plate 32. As can be seen in Figure 10, in the completed lock mechanism the cam 43 is disposed externally of the facing plate 76, and its lobes 41 and 42 are engageable with the enlarged head of the pin 40.

From the above description, it will be manifest that the locking device can be attached to a conventional lock with the minimum of modification to the parts of the latter, so that the cost of the overall locking mechanism is considerably reduced compared with a similar locking mechanism which is specially manufactured. In addition, although the locking device is provided as a separate attachment to the conventional lock, the lock mechanism as a whole is still compact and can easily be fitted into an extruded aluminium frame of a patio door, for example, where the space available for installation of the locking mechanism is severely limited.

In a modification of the above-described arrangement, (not illustrated), the operating bars 47 are extended beyond their points of attachment to the link arms 44 so that they extend in front of the front face 24 of the lock casing 10. When the dead bolts 49 are retracted into their respective casings 48, the extensions of the bars 47 together cover the opening 23 through which the dead bolt 1 7 is extendable.

When the dead bolts 49 are extended, however, the extensions part sufficiently to uncover the opening 23 and allow the dead bolt 17 to be extended. When thus extended, the dead bolt 1 7 obstructs return movement of the extensions of the bars 47, thereby providing an additional measure of security to the interlock which prevents the dead bolts 49 from being retracted until the dead bolt 1 7 is first withdrawn. In this case it will of course be necessary to provide a suitable opening in the extension of the upper operating bar 47 to allow the latch bolt 13 to be extended and retracted without obstruction.

Referring to Figure 15, the locking device illustrated therein is designed to be fitted to a generally conventional lock of the type comprising a casing 10 which slidably houses a latch bolt 13 and a dead bolt 17. The latch bolt 13 can be moved between relatively extended and retracted positions with respect to the casing 10 by means of a rotatable cam (not shown), the cam being mounted on a square-section spindle 1 5 which is in turn keyed for rotation with a manually operable handle (not shown). The dead bolt 17 on the other hand can be moved between relatively extended and retracted positions by means of a key-operated lock unit 20, and is guided in such movement by a pin 18 which travels along a slot 19 in the casing 10.

The locking device itself comprises a pair of plates 31 and 32 which are disposed in face-toface relation against an outer surface of the casing 10, so that the plates are slidable both relative to each other and relative to the casing in the directions indicated by arrow A. The plates 31 and 32 are configured so that they define an opening 38 therebetween, and each plate is provided with a series of rack teeth 39 on an edge thereof which faces into the opening 38. A gear wheel (not shown) is freely rotatably mounted on an extension of the above-mentioned latch bolt operating cam and is engaged on opposite sides thereof by the rack teeth 39 on the plates respectively.

A pin 40 upstands from the plate 31 and is disposed in the path of movement of a pair of angularly spaced lobes of a cam (not shown) which is keyed for rotation with the spindle 1 5.

During normai operation of the handle to retract and extend the latch bolt 13, the cam lobes do not engage the pin 40 and consequently the plates 31 and 32 remain stationary. However, the handle (which is normally biassed into a rest position) can be moved in the opposite direction to that for retracting the latch bolt 13, whereupon one of the cam lobes engages the pin 40 from beneath and raises the plate 31. Such movement is transmitted through the aforementioned gear wheel to the plate 32 so that the latter moves in the opposite direction to the plate 31. Under this action, upper and lower operating bars 47 which are secured to the plates 31 and 32 respectively are moved away from the casing 10 to activate additional locking points at the top and bottom of the closure to which the locking device is fitted.

Lost motion is provided between the handle and the latch bolt operating cam so that the latch bolt is not moved during such movement of the handle, and the handle is biassed to return to its rest position after such movement. During return movement of the handle, the pin 40 is not engaged by the cam lobes so that the plates 31 and 32 remain in their new positions.

Before the plates 31 and 32 are moved in the above-described manner, parts thereof obstruct the slot 1 9 in the casing and prevent the pin 1 8 from travelling therealong, thereby preventing the dead bolt 17 from being extended. However, once the plates have been moved as aforesaid into the illustrated positions, they clear the slot 1 9 and allow the dead bolt to be moved into its extended position. In this position, the pin 18 obstructs return movement of the plates 31 and 32.

In order to return the locking device to its starting condition, the dead bolt 1 7 is first retracted by suitable operation of the keyoperated lock 20. The handle is then operated to retract the latch bolt 13, which action brings the other lobe of the cam into engagement with the pin 40 from above and thereby moves the plate 31 downwardly. At the same time the plate 32 is moved upwardly, so that the operating bars 47 move in unison to de-activate the abovementioned additional locking points.

Reference numeral 76 denotes a facing plate which is secured to the exterior of the casing 10 to cover the plates 31 and 32.

Thus far described, the locking device shown in Figure 1 5 is similar to the construction disclosed in Figures 1-14.

However, it differs from this construction in the following important respects.

The locking device of Figure 1 5 is designed for use with a closure whose surface which faces in the closing direction is overlapped to a considerable extent by the surrounding frame. In the construction disclosed in Figures 1-14, the casing 10 is mounted so that a front face 24 thereof is flush with an edge of the closure, and the bolts 13 and 1 7 in their respective retracted positions do not extend beyond this face. If the locking device of Figure 15 were to be mounted in a similar way, then there may not be sufficient spacing between the framework and the handle on the above-mentioned surface of the closure to allow the handle to be operated comfortably.

Accordingly, it is desirable that this spacing is increased. To this end, a facing plate 90 is mounted in front of the face 24 and is spaced therefrom by means of spacers 91, the locking device being mounted so that the plate 90 rather than the face 24 is flush with the edge of the closure. In addition, the bolts 13 and 17 are increased in length so that in their respective retracted positions they project beyond the face 24 but not beyond the plate 90. An example of the type of closure to which the locking device can be applied is a door whose framework is made of extruded box-section aluminium, for instance. Reference numeral 92 denotes pillars secured to the front face 24 of the casing 10, by means of which the casing is mounted in the box section.

Secondly, in Figures 1-14 the operating bars 47 extend along the above-mentioned edge of the closure and are coupled to the plates 31 and 32 by means of respective arcuate links. In the locking device of Figure 15, however, the bars 47 extend within the box section of the closure framework and are secured to flanged projections 93 which are formed integrally with the plates 31 and 32 respectively.

Thirdly, in Figures 1-14 the pin 18 on the dead bolt 1 7 extends into a slot 78 in the facing plate 76 which is generally congruent with the slot 1 9 in the casing 10. In the locking device shown in Figure 15, a roller 94 is provided on the end of the pin 18, and the slot 78 is increased in its width to accommodate the roller 94. The use of such a roller enables the pin 18 to withstand to a much better degree the shear stresses which it may experience if an attempt is made to move the plates 31 and 32 while the dead bolt 1 7 is not in its retracted position.

The locking device shown in Figure 1 6 is generally similar to that described above with reference to Figure 15, except that it is intended to be mounted with its front face 24 flush with the edge of the closure. Consequently, the facing plate 90 and its associated parts are omitted, and the bolts 13 and 1 7 are not increased in length. In addition, like the construction disclosed in Figures 1-14 the operating bars (not shown in Figure 16) are designed to extend along the aforementioned edge of the closure and are connected to the plates 31 and 32 by means of respective links 95. Each link 95 is pivotally connected at one of its ends to an apertured projection 96 on the respective plate 31,32 and has a flange 97 at its other end to which the respective operating bar is secured.

In order to provide maximum commonality of parts between the locking devices shown in Figures 1 5 and 16, each of the plates 31 and 32 may be manufactured with both a flanged projection 93 and an apertured projection 96. In the case of Figure 1 5 the operating bars 47 are connected to the projections 93 while the projections 96 remain unused, while in the case of Figure 16 the links 95 are connected to the projections 96 and the projections 93 are removed.

Figures 17 to 19 illustrate one form of operating bar (referenced 98) which can be used in the locking device of Figure 16, it being understood that one such bar will be connected to each of the plates 31 and 32. As can be seen to advantage in Figure 17, which is a cross-sectional view of the operating bar and part of the closure framework, the operating bar 98 is generally of flat U-shaped configuration and has outwardlyfacing channels 99 formed in its limbs respectively. The channels 99 are engaged by inwardly directed projections 100 which form an integral part of the closure framework (referenced F), and the operating bar is thereby guided for sliding movement along the edge of the closure.

At one end thereof the operating bar 98 is secured to the flange 97 on the respective link 95.

At its other end (shown in exploded perspective view in Figure 18) the operating bar has a mounting member 101 attached thereto. The member 101 locates in a recess 102 in the underside of the operating bar 98, and is held against movement longitudinally of the latter by means of a projection 103 which engages in a slot 104 in the operating bar 98. A roller 105 locates in a circular aperture 106 in the operating bar, and is secured to the member 101 by means of a fixing element (not shown) which is engaged with a threaded bore.

Referring now to Figure 19, when the closure is moved into a closed position with the locking device de-activated, the roller 105 on each operating bar 98 enters a horizontal limb 108 of an L-shaped slot 109 in the frame (referenced 110) which surrounds the closure, as indicated by arrow B. When the closure is fully closed and the locking device is then actuated, the roller 105 moves along a vertical limb 111 of the slot 109 to the position indicated in broken line at 105', thereby preventing the closure from being opened. The arrangement of the roller 105 and the slot 109 thus replaces the dead bolt and casing construction employed in the locking device described in Figures 1-14.

In order that the engagement of each roller 105 in its associated slot 109 may be adjusted when the door is in its closed position, the roller 105 is disposed eccentrically with respect to the fixing element which secures it to the mounting member 101, so that such adjustment may be performed by turning the roller about the fixing element.

The slot 109 illustrated in Figure 1 9 is associated with the operating bar connected to the plate 31, and its vertical limb 111 extends upwardly from the horizontal limb 108 because the plate 31 and hence the roller 105 move upwardly when the locking device is activated. It will accordingly be appreciated that, in the slot 109 associated with the plate 32, the vertical limb 111 extends downwardly from the horizontal limb 108 because the plate 32 moves downwardly when the locking device is activated.

Claims (3)

Claims

1. A locking device adapted for attachment to a pre-assembled latch mechanism comprising a casing, a latch bolt which is movable between extended and retracted positions with respect to the casing, and a manually operable handle which is operatively connected to the bolt by means of a rotatable spindle, the locking device comprising a cam member mounted on the spindle externally of the casing for rotation with the handle, at least one operating linkage mounted externally of the casing and operatively connected to the cam member, at least one dead bolt which is extendable and retractable by movement of the operating linkage or operating linkages, and means providing lost motion between the cam member and the operating linkage or operating linkages.

2. A locking device for a closure member comprising a manually operable handle biassed into a first position and movable from said first position in one direction into a second position and in the opposite direction into a third position, a latch bolt which is extended and retracted with respect to the closure member by movement of the handle between said first and second positions, a dead bolt which is extended with respect to the closure member by movement of the handle from said first position to said third position and which is subsequently retracted with respect to the closure member by movement of the handle from said first to said second position, a spindle which is rotated by movement of the handle, a rotatable operating element mounted on the spindle and operatively engaged with the latch bolt, and means providing lost motion between the spindle and the operating element.

3. A locking device comprising any novel and non-obvious feature or combination of features disclosed in the preceding description.