Field

[0001] The present invention relates to a latch assembly suitable for a lock in a sliding door, such as but not restricted to, a cavity sliding door.

Background

[0002] Sliding doors are opened and closed in a direction parallel to the face of the door. Sliding door locks include a bolt with a hook which engages a strike plate to retain the door closed. Cavity sliding doors are similar, but are slidable into a cavity in a wall or door frame until the edge of the door in which the latch is mounted is substantially flush with the wall/door frame and the door is concealed within the cavity.

[0003] Sliding door locks generally include a face plate mounted flush with a side edge of the door and an actuation lever (or knob) which protrudes from one or both sides of the door.

However, such protruding levers (or knobs) cannot be used with cavity sliding doors as they prevent the door from completely sliding into the cavity. For this reason, cavity sliding door locks generally include a pair of recessed escutcheons mounted either side of the door, one of the escutcheons housing an actuation lever and the other usually housing an emergency release device. The lever(s) is/are manually pivoted to extend or retract the bolt from the face plate. A strike plate is mounted opposite the edge of the door and includes an opening complimentary to the bolt.

[0004] Sliding door locks generally include a lock bolt of rectangular cross section with a major (longer) axis parallel to the side edges of the door and a minor (shorter) axis normal to the bottom and top edges of the door. When the door is closed, the bolt can be extended which causes a hook to extend from the bolt to engage the strike plate and retain the door in the closed position. To open the door, the bolt is retracted which retracts the hook into the bolt and disengages it from the strike plate. For cavity sliding doors, a recessed pull tab can also be mounted on the door edge containing the face plate. The pull tab pivots out from the door edge so it can be gripped when the door is in the flush or fully open position (and thus the door itself cannot be gripped) and used to pull the door towards the closed position. [0005] The typical sliding doors’ thickness varies from 32mm up to 45mm. The doors normally have a <D54mm hole bored laterally through the panel and a 25mm hole bored longitudinally into the panel. The hole latching and locking mechanism needs to be accommodated within the two bore holes. Further, for cavity sliding doors, the locking and actuation mechanisms needs to fit within the lock body between the escutcheons without protruding outside the rims of the escutcheon (and thus preventing the door from being fully withdrawn into the cavity). For this reason, there are no key latches or only external key operated locks for cavity slider doors that fit into the standard door holes described above and thus, these sliding doors have generally been used in relatively low security settings, such as internally within a home. However, due to demand to optimize space in a home, there is a trend in the use of cavity sliders for garage entry into a home. As such, there is a requirement for a high level of security sliding doors and cavity sliding doors without the need for complicated and expensive custom-made doors.

[0006] In standard lock assemblies for sliding doors, the latch assembly extends into the lock body and occupies a significant amount of the internal space within the lock body. Thus, one problem identified by the inventors when looking to include additional security features into the lock is the lack of internal space within the lock body for these additional security features.

[0007] Australian patent application 200072374 describes an existing lock assembly for use with a sliding door that does not include a lock cylinder. Figure 1 illustrates the lock assembly 10 in the retracted state. This lock assembly 10 includes A lock body assembly 17 which is essentially a hollow, rectangular parallelepiped with a pair of spaced apart side surfaces an open front end, a closed rear end, a full bottom surface, and a partial top surface 17e. A carriage 22 is slidably mounted in the lock body assembly 17 and has an end which acts as a bolt. The lock assembly 10 further includes a hook member 24 having a tip on its distal end is pivotally mounted within an internal recess of the carriage 22.

[0008] A strike plate 8 is mounted to the door frame or wall opposite the edge of the door that contains the latch. The strike plate includes an opening of substantially complimentary size to the end of the carriage 22. Thus, when the door 12 is closed and the carriage 22 is extended, the tip extends from the extended carriage 22 to a first position in engagement with the rear of the strike plate to retain the lock assembly 10 and thus the door in the closed position. [0009] The lock 10 also includes a drive shaft 44 with an interior cross shaped recess adapted to engage with a pair of flat spindle shafts (not shown) which extend from an external actuation lever and an external emergency release device (not shown). The drive shaft 44 is non-rotatably connected to a drive member 52. The drive member 52 is pivotally connected by a shaft to one end of a link member 56. The other end of the link member 56 is pivotally connected by a shaft to the lower proximal end of the hook member 24. The upper proximal end of the hook member 24 is pivotally mounted in the recess 29 of the carriage 22. An over centre spring 53 is mounted between the drive member 52 and the distal end of the lock body assembly 17. The lock body assembly 17 has a camming protuberance and the hook member 24 has first (upper) and second (lower) edges 64 and 66 and first and second surfaces 70 and 71. The latch assembly is operable to move carriage 22 between an extended and retracted state on rotation of drive shaft 44.

Likewise, rotation of drive shaft 44 correspondingly causes the over centre spring 53 to bias the hook member 24 to either a first position in which the hook member 24 projects outward from the extended carriage 22 or a second position in which the hook member 24 is retained within the cavity of the carriage.

[0010] From Figure 1, it is apparent that the carriage 22 must extend through the lock body such that the drive shaft 44 passes through carriage 22 so that over centre spring 53 can operatively bias the carriage 22 between the extended and retracted states by biasing the drive member 52 in either the upper distal or lower distal positions about the drive shaft 45. Thus, this arrangement provides little internal space within the lock body for additional lock elements.

[0011] Australian patent 2011213786 discloses a lock that with a short latch design. However, this lock and latch design have a number of shortcomings. For example, the lock and latch only realises a deadlock, there is no passage lock functionality. Furthermore, because of the internal spring arrangement, the latch will self-retract if there is no retention force.

[0012] It is an object of the present invention to provide a latch suitable for use with locks, such as those for sliding doors and/or cavity sliding doors with enhanced security elements.

Summary of Invention

[0013] In a first aspect of the invention, there is provided a latch assembly comprising: a latch housing comprising first and second openings at opposite ends thereof with a linear axis therebetween, an internal passage between the first and second openings, and a linear cam in a wall of the internal passage between the first and second openings; a hook member comprising: a front hook portion having a leading edge projecting in a direction away from the linear axis (such as for engagement with a strike plate mounted to a doorjamb); and a rear pivot portion comprising: a follower held in slidable contact with the linear cam; and a rotational mount; wherein linear movement of the rotational mount along the linear axis causes the follower to slide over the linear cam and pivot the hook member about the rotational mount to move the hook member between: an extended position in which the front hook portion projects out through the first opening along the linear axis and is pivoted from the linear axis in the direction of the leading edge; and a retracted position in which the hook member is within the latch housing.

[0014] The latch assembly of the present invention provides an easy to assemble latch that requires minimal raw material to fabricate, and is usable with a range of different lock sets, including those with both deadlock and passage lock functions. In contrast, latch assemblies of the prior art are generally designed to accommodate a single type of lock set, e.g. one with deadlock functionality or one with passage lock functionality.

[0015] An advantage of the linear cam arrangement is that it allows a modular and/or compact latch design. Thus, in one or more forms of the invention, the latch assembly is a short or half sized tubular or plain latch assembly. In preferred forms of the invention, the latch assembly has a length in the range of from abut 40 mm to about 60 mm. More preferably, the latch assembly has a length in the range of from about 45 mm to 55 mm.

[0016] Furthermore, another advantage of the linear cam arrangement of the present invention is that it provides a‘flexible’ hook member that will not damage the strike plate if it be extended before door closing. This is because, in such situations, the strike plate will push against the hook member causing the hook member to pivot beneath the strike plate.

[0017] In an embodiment, the latch assembly is a latch assembly for a sliding door or a cavity sliding door.

[0018] In an embodiment, the latch housing further comprises a hollow carriage slidable within the internal passage thereof, the hollow carriage comprising: a front bolt portion, and a rear portion, wherein: the hook member is rotationally mounted within the hollow carriage to the rear portion of the carriage via the rotational mount, the carriage is linearly moveable with linear movement of the rotational mount along the linear axis between the extended position in which the front bolt portion projects out through the first opening along the linear axis and the retracted position in which the carriage is within the latch housing; and the hook member is adapted to pivot outwardly to extend through an opening in the front bolt portion on movement to the extended position and to pivot inwardly to be housed within the carriage on movement to the retracted position.

[0019] In an embodiment, the linear cam is in the form of an elongate channel formed in or on the wall of the internal passage, the elongate channel generally having a channel length along the linear axis but sloped toward the first opening in the direction of the leading edge.

[0020] In an embodiment, the rotational mount is a cylindrical shaft with an axis orthogonal to the axis of the internal passage, and the rear portion of the carriage comprises corresponding radial recesses to receive the shaft.

[0021] In an embodiment, the latch assembly further comprises a link member (such as to operatively couple the latch assembly to a drive assembly within a lock body), the link member comprising: a first end retained within the internal passage and pivotably connected to the pivotable mount, and a second end extending out of the second opening of the latch housing, wherein the link member is linearly driveable along the axis of the internal passage to move the hook member between the extended position and the retracted position.

[0022] In one form of the above embodiment, the second end of the link member comprises coupling structure for attachment to a drive assembly of a lock body or a component thereof.

[0023] In an embodiment, the latch housing is formed from two spaced apart sidewalls, and the internal passage is of generally symmetrical square or rectangular cross-section in a plane perpendicular to the axis of the internal passage; and wherein the linear cam in one of a first pair of corresponding linear cams formed in the spaced apart side walls, and the follower is a cylindrical shaft orthogonal to the axis of the internal passage that extends between the first pair of linear cams.

[0024] In one form of the above embodiment, each sidewall includes a second pair of corresponding linear cams, and wherein the rear portion of the hook member further comprises a second follower extending between the second pair of corresponding linear cams. It is preferred that the first and second pairs of cams are spaced apart on opposite sides of the rear pivot portion of the hook member.

[0025] In an embodiment, the latch assembly further comprises a face plate mounted to the first open end of the latch housing, the face plate having an opening to permit passage of the carriage therethrough.

[0026] In an embodiment, the latch assembly further comprises a fixture adjacent the second opening to attach the latch assembly to a lock body.

[0027] In one form of the above embodiment, the fixture comprises flanged tabs extending from the latch body.

[0028] In an embodiment, the latch assembly does not comprise structure to spring bias the hook member to the extended position or the retracted position.

[0029] In an embodiment, the latch assembly does not comprise structure to spring bias the carriage to the extended position of the retracted position.

[0030] In an embodiment, the latch assembly does not comprise a spring.

[0031] In an embodiment, the latch assembly is sized to fit within a borehole of from about 20 mm to about 30 mm in diameter. Preferably, the latch assembly is sized to fit within a borehole that is about 25 mm in diameter ± 2mm.

[0032] In a second aspect of the invention, there is provided a lock assembly comprising: the latch assembly of the first aspect and/or embodiments and/or forms thereof; and a lock body comprising a drive assembly operatively coupled to linearly drive the rotational mount of the hook member along the linear axis and move the hook member between the extended position and the retracted position.

[0033] In a third aspect of the invention, there is provided a lock assembly comprising: the latch assembly of embodiments of the first aspect of the invention in which said latch assembly comprises the link member; and a lock body comprising: a drive assembly comprising: a drive shaft coupled to one or more rotatable user actuated levers, the drive shaft having a tab radially extending therefrom, wherein the tab comprises a drive pin; a cradle coupled to the second end of the link member, wherein the cradle comprises a slot channel; wherein the drive pin is held within the slot channel to provide a slotted link mechanism such that rotation of the drive shaft causes linear movement of the cradle via the slotted link mechanism to move the hook member between the extended position and the retracted position.

[0034] In an embodiment of the first or second aspects of the invention, the lock assembly is a lock assembly for a sliding door or a cavity sliding door.

[0035] In embodiments of the second and third aspects, the lock assembly further comprises a first lock cylinder accessible by a user from a first side of the lock body, the first lock cylinder operatively connected to the drive assembly to lock the hook portion in the extended position.

[0036] In one form of the above embodiments, the lock assembly further comprises a second lock cylinder accessible by a user from a second side of the lock body, the second lock cylinder operatively connected to the drive assembly to lock the hook portion in the extended position.

[0037] In embodiments of the second and third aspects, the lock assembly does not comprise structure to spring bias the hook member to the extended position or the retracted position.

[0038] In embodiments of the second and third aspects, the lock assembly does not comprise structure to spring bias the carriage to the extended position of the retracted position.

[0039] In an embodiment of the second and third aspects, the lock assembly is sized to fit within a borehole of from about 50 mm to about 60 mm in diameter. Preferably, the lock assembly is sized to fit within a borehole that is about 54 mm in diameter ± 2mm.

Brief Description of Drawings

[0040] Preferred embodiments of the abovementioned aspects of the invention will now be described, by way of examples only, with reference to the accompanying drawings.

[0041] Figure 1 is a lock assembly of the prior art illustrating a latch assembly extending within a lock body of a lock assembly. [0042] Figure 2 is an exploded view of a latch assembly in accordance with one aspect of the invention.

[0043] Figures 3 and 4 show a connecting lock set in the extended and retracted positions.

[0044] Figure 5 is an exploded view of the connecting lock set of Figures 3 and 4.

[0045] Figures 6 and 7 show working views of the lock set of Figure 5 in the extended and retracted positions.

[0046] Figure 8 is an exploded view of a privacy lock set.

[0047] Figures 9 and 10 show the privacy lock set of Figure 8 in the extended and retracted positions

[0048] Figure 11 is an exploded view of a single cylinder lock set.

[0049] Figures 12 and 13 show working views of the lock set of Figure 11 in the extended and retracted positions.

[0050] Figures 14 and 15 show a double cylinder cavity slider lock set in the extended and retracted positions.

[0051] Figure 16 is an exploded view of the lock set of Figures 14 and 15.

[0052] Figures 17a, 17b, and 18 show working views of the lock set of Figure 16 in the unlocked extended, locked extended, and retracted positions.

[0053] Figure 19 is a 3D view of the latch assembly coupled to one half of the lock body illustrating the lock cylinder engaged with the internal lock assembly with the latch locked in the extended position.

[0054] Figure 20 is a 3D view of the latch assembly coupled to one half of the lock body illustrating the lock cylinder engaged with the internal lock assembly with the latch unlocked in the extended position. Description of Embodiments

[0055] The invention is described below with reference to the embodiments depicted in Figures 2 to 20.

[0056] Figure 2 provides an illustration of an embodiment of a latch assembly in accordance with the first aspect of the invention. As illustrated in Figure 2, The latch assembly 10 is essentially a hollow rectangular box having a latch housing formed from two halves 10a, 10b having side walls 11, open ends 12, and an internal passage defined therebetween.

[0057] A hollow bolt (or carriage) 15 is slidably mounted within the internal passage of the latch assembly 10 and has a bolt end 16. The hollow bolt 15 is adapted to extend from the face plate 5 in the extended position through opening 17 and retract substantially flush with the face plate 5 in a retracted position. A hook member 20 has a tip 21 on its distal end having a leading edge 27 (e.g. in the form of a hook). The other end is pivotally mounted within recess 23 of the hollow bolt 15 as discussed below.

[0058] Latch housing body halves 10a, 10b have holes 150 for receipt of fasteners (not shown) to secure the halves 10a, 10b together. The body halves 10a, 10b include elongate guide channels 152 and guide holes 153, both having camming surface 154, 155. These camming surfaces 154, 155 are important for pivoting the hook member 20 as is discussed below.

[0059] The hook member 20 at its pivot end includes three pairs of shafts 25, 28 and 29 extending away from the hook member 20 towards the body halves 10a, 10b. The first pair of shafts 25 extend through holes 156 in the hollow bolt 15 to locate within the guide holes 153 on the body halves 10a, 10b. This allows the hook member 20 to slide longitudinally with respect to the body halves 10a, 10b. The camming surfaces 155 push the tip 21 out of the recess 23 out of the carriage 15 and thus avoid the need for a spring to bias the hook in either of the extended or retracted positions. The second pair of shafts 28 extend through holes 160 in the hollow bolt 15 and to link member 74. The third pair of shafts 29 are locatable within the guide channels 152 on the body halves 10a, 10b, providing support as the hook member 20 slides longitudinally with respect to the body halves 10a, 10b. The camming surfaces 154 allow complimentary movement to the camming surfaces 155. [0060] The latch assembly also comprises a link member or tail bar 74 having a hole 76 at one end for pivotal connection to the shaft 28 of the hook member 20 and at the other end, which projects out the opposite open end 12 from the hollow-bolt with cut-aways 77 for coupling to a drive shaft of a lock body to form a lock assembly as will be described below.

[0061] In use, a striker plate 30 is mounted to the door frame or opposite the edge of the door that contains the lock assembly 1 by countersunk screws which pass through holes 31, 32. The striker plate 30 includes an opening 35 of substantially complimentary size to the bolt end 16 of the latch assembly 15 and face plate opening 17. The opening 35 has an upper edge 36 for engagement with the tip 21 of hook member 20.

[0062] When the door is closed and the hollow bolt 15 is extended, the tip 21 extends from the hollow bolt 15 to a first position in engagement with the rear of the striker plate 30 adjacent the opening 35 and upper edge 36 to retain the lock 1 and thus the door in the closed position. The tip 21 retracts into the hollow bolt 15 in the initial stage of retraction of the carriage 15 for door opening to a second position. The tip 21 remains retracted in the hollow bolt 15 when the hollow bolt 15 is fully retracted into the latch housing 10.

[0063] Advantageously, the latch assembly of the present invention may be used with a variety of different lock assemblies as illustrated in Figures 3 to 11.

[0064] Figures 3 to 7 illustrate an embodiment of a lock assembly 1 having a privacy lock set with a latch assembly according to the present invention. Figure 3 illustrates the lock assembly 1 actuated to the extended position in which the latch 16 and hook portion extend from the latch housing 10 for engagement with a striker plate. Figure 4 illustrates the lock assembly 1 actuated to the retracted position where the hook portion is withdrawn inside the carriage 15, and the carriage 15 and latch 16 are withdrawn inside the latch housing 10. Figure 5 is an exploded view of the lock assembly 1. Figure 6 and Figure 7 illustrate the interaction between the drive assembly and the latch assembly in the extended and retracted positions respectively.

[0065] Broadly, the lock assembly 1 includes a face plate 5 mounted to a side edge of a door (not shown) by countersunk screws which pass through holes 7, 8. The lock assembly 1 includes a latch assembly (such as that described above) 10 that extends from face plate 5 into the door and a lock body. [0066] The lock body of the lock assembly 1 includes a drive assembly therein. The drive assembly comprises a drive plate 50 adapted to engage with a drive shaft 52 formed from the shaft portions of actuation levers 53. The levers 53 are accommodated within a recessed portion 65 of the external surfaces of escutcheons 60 which are to be mounted flush with the sides of the door. The escutcheons 60 include a centre hole 66 to receive the shaft portions 52 and levers 53. The escutcheons 60 also include a screw hole 67 adapted to allow the escutcheons 60 to be screwed to the door stop by way of countersunk screws 6. The actuation levers 53 cover the holes 67 after the levers 53 have been rotated to a locked position. The skilled person will appreciate that a variety of different levers may be implemented.

[0067] In the lock assembly illustrated herein, link member or tail bar 74 is operatively coupled to the drive assembly via a coupling arrangement between cut-aways 77 to a cradle 75. The cradle 75 has arms 78 to be received within the cut-aways 77. The cradle 75 having an elongate hole 80 to receive a shaft 81 on the drive member 50 to allow the drive plate 50 to move the cradle 75. The shafts 52 extend through hole 57 in drive member 50 and the slot in the cradle 75. This arrangement of the shaft 81 within elongate hole 80 provides a slotted link mechanism such that rotation of the drive shaft 52 is translated to a linear movement of the cradle 75 which is operatively coupled to move the latch between the extended position and the retracted position.

[0068] An overcentre spring 105 is provided to retain the cradle 15 under retention force in either an extended or retracted position.

[0069] The lock body 1 further comprises a pull tab 110 on the face plate 5 which pivotable between a position substantially flush with the edge of the door when the door is closed and a position angled outwardly from the door to facilitate manual gripping during closing of the door. The pull tab 110 includes pivot shafts 112 to be received within pivot guides 114 on the face plate 5. The pull tab 110 includes an opening 115 which mirrors in size the openings 17, 35 of the striker plate 30 and face plate 5.

[0070] Figures 8 to 10 illustrate an embodiment similar to that illustrated in Figures 3 to 7, but in which one of the levers 53 is omitted and instead replaced with emergency button 58. Figure 8 is an exploded view of the lock body 1, wherein like parts are given the same numerical identifier as per the description generally corresponding to Figures 3 to 7. Figures 9 and 10 illustrate the interaction between the drive assembly and the latch assembly in the extended and retracted positions respectively showing emergency button 58.

[0071] Figures 11 to 13 illustrate another embodiment of a lock assembly 1 having a lock body with a single cylinder lock set and a latch assembly according to the present invention. Note that, as above, like parts are given the same numerical identifier as per the embodiment illustrated in Figures 3 to 9. However, in this case, and as best illustrated in Figure 11, the lock body further comprises a lock cylinder 71 which interacts with an internal lock arrangement to lock the latch assembly 10 in the extended position. Atypically, the lock cylinder 71 is axially offset from the drive shaft.

[0072] The internal locking arrangement comprising a rotor 90 that is connectable by way of circlips 93 to the shaft 52. The rotor 90 further includes a tab with slot 94 having a notch 95 adapted to receive a protuberance 100 on the cradle 15. The protuberance 100 being aligned with and lockable within the notch 95 to lock the cradle 15 in extended positions.

[0073] The lock cylinder 71 includes a keyhole for receiving a key, rotation of a key within the keyhole causes rotation of lock element 92. Lock element 92 has a radial tab extending therefrom. The lock element 92 is rotatable between a first position in which the radial tab biases an internal locking arrangement to the position of engagement when the latch is extended, and a second position in which the radial tab biases the internal locking arrangement to the position of disengagement. Figures 19 and 20 illustrate the internal locking arrangement in the position of engagement (i.e. locked) when the latch is extended and disengagement (i.e.

unlocked) respectively.

[0074] As shown in Figure 19, in the position of engagement (i.e. locked), the lock element 92 is rotated counter-clockwise such that the tab is biased against the rotor 90. This causes a clockwise rotation of the rotor 90 which likewise causes rotation of the slot 94 such that protuberance 100 on the cradle 15 is located within the notch 95 of the slot 94. This locks the cradle 15 in position with the latch in the extended position.

[0075] As shown in Figure 20, in the position of disengagement (i.e. unlocked), the lock element 92 is rotated clockwise such that the tab is biased against the rotor 90. This causes a counter-clockwise rotation of the rotor 90 which likewise causes rotation of the slot 94 such that protuberance 100 is moved out of notch 95 of the slot 94. This unlocks the cradle 15 which allows movement of the latch between the extended and retracted positions.

[0076] Figures 12 and 13 show moving parts of a single cylinder lock set in an

extended/retracted position. In both positions, the latch (lock) can be driven by the internal snib (lever) 53 or external key to lock or unlock the lock assembly 1.

[0077] Figure 14 to 18 illustrate an embodiment of a lock assembly 1 having a double cylinder lock set with a latch assembly according to the present invention. This embodiment is similar in operation to the single cylinder lock set embodiment described above with like parts being given the same numerical identifier. However, in this case, both the outside and inside facing escutcheons comprise a lock cylinder 71. This allows the lock to be locked and unlocked from both the inside and outside faces of a door.

[0078] It should be noted that to fit both lock cylinders into a lock body which is sufficiently thin to be suitable for a sliding door (and in particular, a cavity sliding door) the lock cylinders are not axially aligned as is typical in a standard two-cylinder lock arrangement. Instead, each lock cylinder 71 is axially offset from each other, while substantially overlapping within the lock body along their parallel axis. This arrangement provides for a compact lock body design, since the thickness of the lock body is a function of the length of the lock cylinders 71 (e.g. in a standard design, the width of the lock body is dictated by a length that is twice the length of a single lock cylinder, since there are two lock cylinders that are axially aligned). In this regard, the lock cylinders are also atypically axially offset from the drive shaft. This in turn limits the internal space within the lock body for a latch assembly. Thus, making the latch assembly described herein useful in a sliding door lock assembly having a double cylinder lock set.

[0079] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in other forms.