AU1016402A - A lock for a displaceable wing (bb) - Google Patents

Description

File:14699-99 Jan7 02BB Child-Control Title A lock for a displaceable wing.

Field of the Invention o This invention relates to locks for sliding wings. A typical such wing comprises a patio door comprising a piece of glass supported by a narrow timber or aluminium frame, the frame being supported by rollers to enable the door to be moved in a direction parallel with the plane of the face of the door.

S 20 PriorArt Commonly, the interior portion of the lock for patio doors comprises an interior handle portion supporting a hand operable member, the interior portion being mounted on the closing edge of the door and is supported on the face of the frame by two screws that pass through the door frame to engage in an exterior handle portion on the exterior side of the door.

There are many types of such locks for patio (herein also referred to as sliding glass) doors 00 "available having an arm with a hook shaped end that is pivoted into the engaging position while in other cases it is slid into engagement; in these types of locks, engagement is usually effected by operation of the hand operable member or key and after the door and a catch are adjacent and able to be engaged.

Commonly available locks do not have a self-latching capability whereby the lock automatically engages the catch plate as the door is closed and so in general, a closed door remains unrestrained until the lock is hand actuated. An objective of this invention is to provide a lock that is self-latching. Another objective is to provide a lock for sliding glass doors where the cylinders are more accessible for ease of use. Yet another objective is to provide a lock that is difficult for a child to operate. These, and other objectives are addressed.

2 Summary of the Invention According to the invention there is a lock for a displaceable wing supported adjacent an opening, said lock including and a catch plate supported by an element defining part of the opening and a first lock portion, said first lock portion including an interior portion mountable to the wing and including a handle portion, hand operable means and stop means to restrain the hand operable means an exterior portion mountable to the wing and including a handle portion, engaging means including at least one engaging arm engageable with the catch plate in hooked engagement to restrain the wing from being displaced in an opening direction and being actuateable by the hand operable means to release the catch plate to enable the wing to be displaced in an opening direction, at least one lock cylinder having a key operable barrel an angularly displaceable first cam, said first cam operably connecting each barrel to the 15 engaging means to enable the engaging means to be actuated by the barrel, the engaging means being controlled by the angular disposition of the first cam wherein the first lock portion cannot be released from the catch plate by the hand operable means when the first cam is disposed at a locking disposition S: 20 In some embodiments the engaging means includes a latchable first arm defined in part by an engageable position in which it is engageable with the catch plate in hooked engagement to restrain the wing from being displaced in an opening direction, said first arm automatically engaging with the catch plate in hooked engagement as the wing is moved in a closing direction and preferably, the hand operable means includes a hand operable unlatching member and the first arm is operably connected 25 to the unlatching member to enable the first arm to be released from the catch plate by unlatching member operation, and wherein the stop means comprises a displaceable outwardly biased button that must be displaced against biasing means to an inactive position to enable the unlatching member to be operated, and wherein each barrel is operably connected to the first arm by the angularly displaceable first cam to enable each barrel to release the first arm from the catch plate. Preferably, the first arm is spring biased towards the engageable position and displaceable from the engageable position by the catch plate during displacement of the wing in a closing direction and preferably, the first arm has a hooking engaging end. In these embodiments there is optionally an exterior lock cylinder supported within the exterior portion and having a barrel, said barrel being operably connected to the first cam by a shaft having passage through the wing and there is optionally an interior lock cylinder supported within the interior portion and having a barrel operably connected to the first cam, and where preferably each barrel is operably coupled with free movement to the first cam and preferably coupled by slide means.

In some embodiments, the engaging means includes a second arm defined in part by an engageable position in which it is engageable with the catch plate in hooked engagement to restrain the wing from being displaced in an opening direction and preferably, the hand operable means includes a locking member, said locking member being operable to actuate the second arm to and from the engageable position, said second arm being operably connected to each barrel by the first cam to enable each barrel to actuate the second arm to and from the engageable position, the second arm being controlled by the angular disposition of the first cam wherein the second arm cannot be actuated from the engageable position by the locking member when the first cam is disposed at a locking disposition. Preferably, the lock includes a locking slide operably inconnecting the first cam and second arm, said first cam having an extension including an operative end portion disposed from the first cam pivotal axis, said locking slide including a drive recess defined by drive shoulders, and 15 wherein the locking slide is displaceable by the locking member to actuate the second arm to and from the engageable position when the operative end portion is between the drive shoulders and preferably, the locking slide is unable to be displaced by the locking member to displace the second arm when the operative end portion is not between the drive shoulders and preferably, when the first cam is at a locking disposition the point of contact on the locking slide by the operative end portion is 20 defined by a normal vector that passes substantially through the axis of rotation of the first cam.

Preferably, the locking slide comprises a rectilinearly displaceable slide and preferably, the second arm has a hooking engaging end. Preferably, the lock includes stop means to restrain the second arm from being displaced to the engageable position unless the first lock portion and catch plate are adjacently disposed, said stop means including an outwardly biased and inwardly displaceable 25 plunger-like member supported within the interior casing. In these embodiments there is optionally an exterior lock cylinder supported within the exterior portion and having a barrel, said barrel being operably connected to the first cam by a shaft having passage through the wing and there is optionally an interior lock cylinder supported within the interior portion and having a barrel operably connected to the first cam, and where preferably each barrel is operably coupled with free movement to the first cam and preferably coupled by slide means.

According to the invention there is also a lock for a displaceable wing supported adjacent an opening, said lock including a catch plate supported by an element defining part of the opening, an interior portion mountable to the wing and including a first cam, a lock cylinder having a key operable barrel, engaging means engageable with the catch plate in hooked engagement to 4 restrain the wing from being displaced in an opening direction, said engaging means comprising an upper and a lower engaging arm, hand operable means by which to actuate the engaging arms and a button that must be displaced to an inactive position to enable the hand operable means to be operated, an exterior portion mountable to the wing and including a lock cylinder having a key operable barrel that is operably connected to the first cam by a shaft that has passage through the wing, each said engaging arm being defined in part by an engageable position in which it is engageable with the catch plate in hooked engagement to restrain the wing from being displaced in an opening direction, each said engaging arm being operably connected to each barrel to enable each engaging arm to be actuated from its respective engageable position by operation of either barrel and each said engaging arm being displaceable from its respective engageable position by the hand operable means, the engaging means being controlled by the angular disposition of the first cam wherein the 1 aengaging means cannot be released from the catch plate by the hand operable means when the first 15 cam is disposed at a locking disposition, and preferably, the hand operable means includes a locking member operable to actuate an engaging arm to and from the engageable position and includes an unlatching member operably connected to an engaging arm to enable this arm to be released from the catch plate by unlatching member operation.

Preferably, the wing comprises a sliding door.

Description of the Drawings Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings in which Figure 1 is a schematic partial side view of the interior portion, when viewed from that interior side, Figure 2 is a schematic partial sectional view of the lock of Figure 1 when viewed from the opening edge of the wing, Figure 3 is a schematic partial side view of the exterior portion, when viewed from the exterior side, Figure 4 is a schematic partial plan view of the lock, and a partial cross-sectional view through the wing and the element defining part of the opening, Figure 5 is a schematic partial vertical cross-section through the disabling device, Figure 6 is a partial schematic enlarged side view of the marked area, Figure 7 is a partial side view of the rocker providing points of attachment for rods that 15 operate remote locks, Figure 8 is a schematic partial side view of the lower end of the locking slide showing an impact absorbing connection to the second arm 22, Figure 9 is a schematic partial side view of the slides and cylinder where the cylinder is disposed rearwardly of the first cam, 20 Figure 10 is a schematic partial side view of slides and a cylinder of the lock of Fig 1 illustrating that the pivotal axii of the barrel and first cam lie in a vertical plane.

.oo..i ooo.

oo 6 Description of the Preferred Embodiments In a preferred embodiment, in summary, the interior portion of the lock comprises an interior portion (referred to previously but less meaningfully as a lever assembly) including an interior casing and an interior handle portion the interior portion being mounted adjacent the closing edge of the wing and on the face of the frame 50 of the wing by two screws that pass through two apertures in the interior casing and wing frame to engage in an exterior portion (referred to previously as a lever assembly) on the exterior side of the frame and including a handle portion. A third aperture located midway between the first two provides passage for a shaft.

The interior portion includes a box-like interior casing 1, that preferably comprises a cavity within a handle assembly as shown in Figure 1.

In preferred embodiments the interior portion includes a latchable first arm that projects forward to extend from an aperture in the front wall of the interior casing 1 to engage, (in usage), in a recess in a catch plate 24 mounted on the face of the element 50A defining part of the wing opening and these embodiments preferably include an interior hand operable unlatching member.

15 In other preferred embodiments the interior portion includes a second arm that projects from an aperture in the front wall of the interior casing 1 to engage, (in usage), in a recess in a catch plate 24 mounted on the face of the element defining part of the wing opening and these embodiments preferably include an interior hand operable locking member.

In other preferred embodiments again, the lock includes both the first and the second arm.

20 All embodiments optionally include exterior and interior cylinders.

In embodiments employing the interior cylinder, there is supported within the interior casing a key operable interior cylinder 3, having an angularly displaceable barrel as is well known, and on the internal end of the barrel is an annular washer having an extension comprising the arm 4, by which the barrel operates the lock. Importantly the barrel is operably connected to a first cam 16 25 described below. This connection may take many forms; it may comprise for example, one or more pinned protrusions of the barrel locating within one or more recesses in the first cam 16. The preferred form employing an interspaced slide however, and as shown in the figures, enables a low casing height and facilitates easy insertion and replacement of cylinders by simply removing a back or lid of the casing the cylinder is simply supported between such.

Accordingly, there is supported adjacent the internal end of the barrel end and co-axially with the barrel is a disc-like member 5 having radially protruding shoulders 6 and 7 between which the armed extension 4 of the washer locates with free movement to drive the disk-like member 5 the free movement enabling a barrel to be rotated in one direction to displace the disc-like member 5, to operate the lock and then to be returned to the undisplacedposition to enable key removal. The disclike member 5 has an armed extension 8 that locates within a substantially rectangular recess 9 within a first slide 10 supported by the interior casing for sliding movement.

Alternatively, not shown, the disc-like member 5 may have an arm having an orthogonal pinned protrusion which locates within a slot within the side of the slide 10 and alternatively, again not shown, the disc-like member 5 may have a geared profile which engages with a mating geared rack portion comprising an edge portion of the first slide. Importantly, and as in the embodiment shown in the figures, the interior cylinder 3 (when included) and slide 10 are always operably coupled, (with some free movement) so that each may impart displacement to the other within the range of normal movement; and in the preferred embodiment shown, the armed extension 8 is always within the recess 9 coupling the two in slide/follower relationship. More specifically, the slide 10 is coupled with some free movement to the key operable angularly displaceable barrel of the cylinder.

In all embodiments, there is supported by the interior casing an angularly displaceable cam 16 (also called herein a first cam 16) preferably having an axis of rotation parallel that of the cylinder barrel. This cam has an armed extension 17, similar to and preferably substantially the same as extension 8, which locates within a substantially rectangular recess 18 of the first slide 10, similar to recess 9. Importantly the armed extension 17 is always coupled to the slide 10 so that each may 15 impart movement to the other within the range of normal movement; in the preferred embodiment shown the extension 17 is always within the recess 18.

*Within the underside of first cam 16 is a rectangular aperture 19 to accept and mate with a rod 20 that passes through the wing to engage similarly in a cam within the exterior portion. In the embodiment shown, slide 10 can always be actuated to move by rotation of the rod 20 or by operation 20 of the cylinder 3 because of the operable coupling described above between the cams 5 and 16 and the slide 10. Referring to the figures, it can be seen in fact, that it is a operative end of the arm 17 disposed from the axis of rotation of the cam 16 that engages between upper and lower opposed shoulders that define the recess 18.

In the embodiments including an exterior cylinder, the exterior handle portion includes 25 elements similar to those described above as shown in Fig. 3 and although better described below, a brief description is provided here to explain a important aspect of the lock. The rectangular rod 20 that passes through a third aperture in the wing locates in a mating rectangular recess in a second cam 36 that has an axis of rotation co-axial with that of first cam 16, said second cam 36 has an armed extension 37 which engages in a substantially rectangular recess 38 of a third slide 39 supported within the exterior casing 45 for sliding movement, said exterior casing comprising part of the exterior portion. Positioned above the cam is an exterior cylinder 41 and an associated disc-like member 44 to which it is coupled with free movement by means described with reference to the interior cylinder, said disc-like member 44 having an armed extension 42 that engages in a substantially rectangular recess 43 in the slide 39. The cam 36 and the disc-like member 44 are operably coupled by the intermediate slide 39 such that movement of one causes the other to displace accordingly, in the same way that cams 16 and 5 are coupled by slide In embodiments employing both the exterior cylinder 3 and the exterior cylinder 41 each cylinder must be able to independently operate the lock irrespective of the configuration in which the lock is left after a previous operation. For example a lock when locked from the inside of the wing by key must be unlockable from the exterior by key and consequentially the mechanism interconnecting each cylinder to the other can be operated at all times by either cylinder.

The exact location of each cylinder is inconsequential to the lock operation and the cylinder barrels and first cam may lie in a vertical plane as shown in Fig 10. Preferably for ease of use, each cylinder is located well back from the front edge of the lock casing and rearward of the first cam as shown in Fig 9 where the recess 9 within first slide 10, (and preferably the recess 43 within second slide 39) is rearwardly disposed as shown in Fig 9 the respective casing being widened to accommodate this relocation of the cylinder. Alternatively the cylinders may be angled outwardly from the edge of the wing. The cylinders may also be located so the barrels are co-axial with the shaft S:09. 20, in which case the first and second slides would be omitted and the barrels would engage directly oooo with the cams 16 and 36 with free movement to facilitate independent operation by each cylinder.

15 The preferred embodiments employ the first and second slides to facilitate the provision of preferred interior and exterior assemblies that have improved ergonomic aspects, that protrudes a minimum distance from the face of the wing, and enables cylinders to be located well back from the edge of the door to provide improved accessibility for key operation.

In embodiments including an interior locking member, the lock can be locked by either 20 cylinder to become unable to be displaced from the locked configuration by the locking member.

In the embodiments including a second arm 22, there is preferably supported by the interior casing 1 a hand operable locking member 11 coupled to a cam 12 having an armed extension 13, (and 0..

which is preferably similar to the armed extension and which locates within a substantially rectangular recess 14 of a third slide 21, (also referred to herein as a locking slide), to operably couple 25 the third slide to the cam 12, supported within the interior casing 1 so that the locking slide 21 may be caused to displace by operation of the locking member 11. Importantly the locking member is always operably coupled to the locking slide 21 so that one may be displaced to displace the other. The coupling may take many forms and may comprise, for example, a geared cam 12 mating with a geared rack portion of the slide 21, but in the preferred embodiment shown, armed extension 13 is always within recess 14.

As will be described below, when the locking slide 21 has been displaced to the upper limit of displacement (the engageable position) and locked by a cylinder, it cannot be displaced from that configuration by the locking member 11.

The third slide, (locking slide) 21 supports the second arm 22, (also referred to herein as a bolt) that is engageable behind a shoulder 23 of a catch plate 24. The third slide has a substantially rectangular recess 25 defined by opposed upper and lower drive shoulders, said drive shoulders being engageable by the armed extension 17 of the first cam 16. Importantly the upper drive shoulder, (of embodiments including a second arm), is joined to an upwardly angled locking exit surface 26 and the lower drive shoulder, (of embodiments including a first arm), is joined to a downwardly angled unlatching exit shoulder 27 as shown in Fig 6, said exit surfaces enabling the operative end of the armed extension 17 to slide over the surfaces 26 and 27 while not causing the third slide to displace substantially. The lock is configured such that when the third slide is between and displaced from its upper and lower extremities of displacement the first cam 16 and the third slide are operably coupled so that one may be displaced to displace the other but at the upper and at the lower extremity of third slide displacement, and corresponding to the operative end portion of the arm 17 being adjacent an exit surface 26 or 27 respectively, the first cam 16 is displaceable in coupled engagement with the first slide 10, (and consequently in coupled engagement with slide 39, the rod 20, and cylinder disclike members 5 and 44) while the third slide is restained from displacement by the armed extension 17.

It can be seen from the figures that at the upper extremity of third slide displacement, the 15 surfaces 26 is disposed substantially orthogonally to the pivotal axis of the first cam 16 while at the lower extremity of third slide displacement the surface 27 is disposed substantially orthogonally to the pivotal axis of the first cam 16. The upper extremity of the third slide displacement (called herein a locking position) corresponds to the second arm being in the engageable position which in practice would be behind shoulder 23 of the catch plate, while the lower extremity corresponds to an 20 undisplaced third slide.

The configuration where the second arm is engaged with the catch plate and the operative end portion of the arm 17 is on the surface 26 and removed from the recess between the drive shoulders corresponds to an engaged and locked lock locked having the meaning of requiring unlocking by key before disengagement can be effected. This functionality derives from the third 25 slide being unable to be displaced while the operative portion is on surface 26 since any attempted displacement of the third slide gives rise to a force on the first cam which is defined by a vector passing the pivotal axis of the first cam and that does not give rise to a moment on the first cam that might cause it to rotate.

In embodiments including the first arm, there is supported for pivotal movement co-axially with the cam 16, an annular member 28 having an armed extension 29 which supports the first arm (also referred to herein as a latching beak), which is able to displace against biasing means, (to a disengaged position), to subsequently engage behind shoulder 80 of the strike plate in hooking engagement.

Cam 16 has a radially displaced shoulder 31, which is engageable with shoulder 32 of the extension 29 to drive the extension angularly to cause the first arm to displace from the engageable position, (which in use would be to disengage the strike plate). Importantly the shoulders are relatively angularly disposed such that the angular displacement of the first cam 16 which causes the first arm 30 to displace from the engageable position substantially corresponds with displacement of the first cam armed extension 17 over the exits surface 27 of the third slide 21 which, as described above, remains restrained stationary, (to enable in usage), the first arm 30 to be disengaged from the strike plate without moving the second arm 22 from the undisplaced position.

In embodiments including a first arm 30, there is preferably positioned in the vicinity of the extension 29, a hand operable member comprising an unlatching member 70, that is engageable to the arm 29 such that it can be operated to cause the arm 29 to rotate to displace the first arm 30 out of engagement with the catch plate. As described above, the first arm 30 is operable from the interior by the unlatching member and by key. The unlatching member may alternatively take the form of a lever supported coaxially with the cam 16 for angular movement, (not shown), which has an associated armed extension that locates adjacent to shoulder 32, said lever being operable to cause the extension to push upwards on the extension 32 to cause arm 29 to rotate to cause the first arm to disengage the strike plate.

15 The exact design is inconsequential to the functionality, but what it is important is that the S arm 29 is supported with free movement to facilitate latching by the first arm 30 wherein the first arm S" "30 on striking the catch plate during closing of the door slides is displaced against the biasing action of spring 33 to subsequently be displaced to the engageable position and behind the shoulder 80. The arm 29 is biased towards the undisplaced, engageable position by a spring 33 and the first arm 30 has e** S• o20 a ramped leading edge portion which on making engagement with shoulder 80 during latching engagement is caused to slide up the shoulder 80 and once the ramp has moved past the shoulder the hook 30 is moved by the spring to engage behind the shoulder 80 this latching of a hooked member eeeee is also well known.

The exterior portion comprises a handle and in embodiments including a first arm 30, it 25 optionally includes an exterior unlatching member 46 for operating the first arm. The exterior portion is preferably retained by the screws which have passage through apertures 2 and which pass through the wing and engage in elongated bosses of the exterior casing 40. The rectangular rod 20 which passes through the third aperture in the wing, (preferably located midway between the other apertures as shown), locates in a mating rectangular recess in the second cam 36. The second cam 36 has an axis of rotation co-axial with that of first cam 16, said second cam 36 has an armed extension 37 which engages in a substantially rectangular recess 38 of a third slide 39 supported within the exterior casing 45 for sliding movement, said exterior casing comprising part of the exterior portion.

Positioned above the cam is an exterior cylinder 41 and an associated disc-like member 44 to which it is coupled with free movement by means described with reference to the interior cylinder, said disclike member 44 having an armed extension 42 that engages in a substantially rectangular recess 43 in the slide 39. The Cam 36 and the disc-like member 44 are operably coupled by the intermediate slide 39 such that movement of one causes the other to displace accordingly, in the same way that cams 16 and 5 are coupled by slide The exterior displaceable unlatching member 46 preferably comprises a radial extension 46A, disposed from the axis of rotation 46B of the said member and which is engageable within a peripheral recess 47 of second cam 36 when the operably connected armed extension 17 of the first cam 16 is adjacent the start of the surface 27, and as described previously, in this configuration the second arm 22 is undisplaced. The first slide 10 is the able to displace in an unlatching direction as the armed extension 17 slides over the surface 27 and so the second cam 36 and first cam 16 (which are connected by shaft 20) can be simultaneously displaced by operation of the exterior unlatching member to cause unlatching of the first arm 30. When the third slide is in a position removed from the undisplaced position, the corresponding position of the recess 47 is such that it is not within the locus of movement of the extension 46A and therefore the exterior unlatching member is not able to operate the second cam to displace the first arm, and consequently when the lock is locked the recess 47 is withdrawn from an operative position.

15 Importantly it can be seen that part of the angular displacement of the sub-assembly comprising members 16, 20 and 36 (which are directly coupled without free movement) is utilizes for operating the first arm 30 while holding the second arm 22 in the undisplaced and non-engageable position, while another part of the angular displacement is utilized for displacing the second arm 22 between the engageable position and the undisplaced and non-engageable position while leaving the 20 first arm 30 undisplaced, and a third part of the angular displacement is utilized for displacing the armed extension 17 to lock the lock by acting to restrain the second slide 21 and hence to restrain second arm 22 from being displaced from the engageable position.

As stated above, in the embodiment described herein, the key locking functionality is controlled by the coupled members 5, 10, 16, 20, 36, 39 and 44 and this chain can be actuated by 25 either cylinder 41 and 3 an important prerequisite for this is that there be sufficient free movement .•between the cam 5 and the barrel of cylinder 3 and between the cam 44 and barrel of cylinder 41 as described above. It should be noted that to enable locking by interior locking member, the first cam 16 has a neutral position corresponding to the extension 17 being adjacent the surface 27 while being within the recess between drive shoulders.

Preferably, the first slide 10 is releaseably retained in the locking position by a detent device, not shown but well known, comprising an outwardly biased ball supported within a recess within an edge of the slide and adjacent a mating recess within a interior casing wall within the loci of movement of the ball such that when the armed extension 17 is on face 26, first cam 16 is locking the third slide 21) the ball engages within both the recesses to require a significant force on the slide 21 to cause the ball to be dislodged from the recess in the interior casing. Preferably there is a second recess corresponding to the first cam 16 being in the neutral position where the armed extension 17 is between the drive shoulders and adjacent surface 27. As with other locks and as is well known, the detent may also comprise a spring biased rocker arm which presses on the first cam 16 to restrain displacement and which urges the first cam 16 towards the neutral position when in the vicinity of the neutral position and which urges the first cam towards the locking position when in the vicinity of the locking position.

In embodiments where there is no key operable cylinder within the interior portion, the slide and the chamfered or radiused surface 26 are optionally be omitted so that the second arm can always be displaced to the disengaged position by the interior by locking member 11, i.e. the exterior barrel cannot be operated to render the locking slide 21 immoveable by the locking member 11.

In other embodiments, the cylinder barrel is replaced by a hand operable thumb-turn.

In other embodiments the interior unlatching member 70 is omitted and in other embodiment again the external unlatching member 46 is omitted and in these latter embodiments the lock is operable by cylinder or as described immediately above, by a thumb-turn lever.

In the locked configuration the fixing screws are preferably covered by plates 34 which i 15 comprise extensions to the locking slide 2 land which during locking are moved vertically from below the said screw heads to be adjacent and over the fixing screws to render them inaccessible and similarly adjusting screw 35 which is accessible through an aperture within the interior casing in the unlocked position is moved to be remote from this aperture when locked, to be inaccessible.

One of the problems sometimes encountered by sliding wing locks is damage when a locked •20 lock is slammed against the catch plate 24. In a preferred embodiment this is addressed by having a device comprising a displaceable auxiliary bolt 51 outwardly biased by spring 54, said auxiliary bolt having rearwardly a shoulder 52 of increased height as shown, such that when the catch plate is remote from the lock and now longer holds the auxiliary bolt depressed, the shoulder 52 is adjacent, to engage a flat portion 53 of the cam 12 to prevent rotation of this cam to thereby restrain the third 25 slide from displacing from the disengaged, undisplaced position and as a consequence to ensure that i the second arm 22 cannot be displaced to the engageable position. Inward depression of this auxiliary bolt through engagement with the catch plate causes the shoulder 52 to be moved out of the path of movement of cam 12 to enable the lock to be locked.

In another embodiment, the second arm 22 to locking slide 21 junction may include a partly compressed compression spring which is further compressible to absorb energy of wing closing. This preferably comprises a slideable plate 60 supported within a slot 61 of the locking slide 21 and urged towards the front edge by the partly compressed spring 62 said plate 60 having a threaded fixing aperture in which the screw 35 locates to fasten the second arm to the plate 60. If the second arm 22 is impacted inwardly the slide plate 60 moves inwardly against increasing spring force to absorb some or all of the energy of impact to reduce the damage to the lock.

It should be noted that both points of attachment 35 for second arm 22 and 81 for first arm accommodate adjustment by having slotted apertures in the first arm and second arm additionally the mating surfaces are knurled to prevent slipping between members and raised side walls on members 21 and 29 prevent sideways slipping of the associated arm.

In preferred embodiments the internal portion comprises a D shaped handle portion as shown in Fig 1 having an unlatching member 70 supported by the interior casing for angular rotation about a boss 66 and having an arm joined at the pivot point and angled so as to locate adjacent the extension 29 to be engageable with an anular boss 65 projecting from the side of arm 29. Operation of the unlatching member causes the annrm to rotate to engage the boss 65 to cause the first arm 30, arm 29 and member 28 sub-assembly to be rotated to displace the first arm 30 from the engageable position.

As shown, the unlatching member is biased by spring 67 towards the undisplaced, engageable position. The exterior portion also preferably comprises a similar a D shaped handle portion as shown in Fig 3. Preferably the unlatching members are configured to pivot while unlatching in a direction corresponding substantially to the direction of wing opening so that in a simple natural motion the handle portion may be gripped and pulled in a simple natural motion.

15 Within the interior handle portion shown there is optionally a disabling device 72 comprising one or more push buttons requiring depression before unlatching can occur by unlatching member operation such a device to make it difficult or impossible for children to unlatch the lock. In the device shown the device comprises a push button 73 supported within the unlatching member 70 and which protrudes through an aperture 74 in the wall of the handle portion when the unlatching member 70 is in the undisplaced position. This button is outwardly biased by spring 75, has a conical head and as shown in Figure 8 that is operable by a finger to be moved to a position below the handle surface to enable the unlatching member 70 to be rotated to operate the lock. The degree of difficult can be determined by the position and number of such buttons that must be simultaneously depressed while operating the unlatching member.

25 In lock optionally provides for remote locking by providing points of attachment for rods that •connect to remote locks or vertically moving bolts. The rods 81 and 82 connect to opposite ends of a rocker member 83 by pin joint and preferably each rod includes a right-angled return that locate in apertures in an end of the rocker member 83, said rocker member 83 is connected to the cam 12 by a shaft 84 as shown. When the locking slide displaces upwards the shaft 82 is driven upwardly while the shaft 81 is be driven downward. The rocker member as drawn would preferably be inserted within the wing frame and the shaft would pass into the frame to support and drive the rocker. Alternatively, not shown, the rocker is supported between interior casing 1 and the wing frame in a concave recess in the underside of the interior casing wall and is connected to the cam 12 by a shaft 84. The remote lock operating rods 81 and 82 have right-angled return that pass through vertical slots in the wing frame to locate within the apertures in the cam the vertical slots accommodating vertical displacement of the right-angled returns that pass through the wall of the frame. This later 14 arrangement is quickly fitted by inserting the rods, placing the rocker over the rods returns and securing the rods to the rocker and then placing the shaft 84 into the rocker 83 as the interior portion is fitted to the wing.

In the above description and claims, the terms first arm and second arm means separate arms that can be included one without the other or one with the other.

The invention provides many embodiments by the inclusion of different elements, e.g. the first arm may be omitted while the second arm is included, one or both of the interior and exterior cylinders may be included, the locking member may be omitted or included, the child proofing feature may or may not be included.

In the above description the spatial prepositions, below above etc. are used for convenience of description only referring to a lock attached to a wing in the manner shown but they have no meaning beyond that.

Although the invention is described with reference to locks for sliding wings having, elements of the embodiments described are also applicable to other types of locks such as locks for 15 hinged doors having sliding bolts.

Throughout this specification and claims which follow, unless the context requires otherwise, S" the word" comprise" and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers and the positional prepositions such as up, down, rear which are used to assist in description of the preferred embodiments have in general no absolute significance.