S&F Ref: 901141 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address Azuma Design Pty Limited, of Applicant: an Australian company, ACN 002 031 307, of 160-162 Newton Road, Wetherill Park, New South Wales, 2164, Australia Actual Inventor(s): Michael Brian Alchin Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: A lock Associated Provisional Application Details: [33] Country: [31] Appl'n No(s): [32] Application Date: AU 2008901475 27 Mar 2008 The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(2035663_1) 1 A LOCK FIELD OF THE INVENTION The present invention relates to locks and more particularly but not exclusively to "surface mounted" locks. BACKGROUND OF THE INVENTION Surface mounted locks are mounted on an internal surface of a door and are operated to engage the door jamb. Typically, the lock will have a knob that is gripped by a user and turned angularly to retract the locked tongue. Still further, it is typical for the knob to have centrally mounted of it a locked cylinder that is operable to prevent operation of the knob to retract the tongue. The lock is operated externally by means of a key. An example of the above discussed locks is described in Australian Patent No. 702534. A further such lock is described in Australian Patent No. 735027. The locks of these patents have the above discussed knob, with the knob prevented from operation by pawls. The pawls are moved by means of centrally mounted actuator. OBJECT OF THE INVENTION It is the object of the present invention to provide an alternative construction to the above mentioned locks. SUMMARY OF THE INVENTION There is disclosed herein a lock including: a base; a lock tongue mounted on the base for linear movement between an extended position and a retracted position with respect to the base, in the extended position the lock tongue is engageable with a striker mounted on a door jamb; and a knob assembly mounted on the base for angular movement about a knob axis to cause movement of the tongue from the extended position to the retracted position, and wherein said knob assembly includes, 2 a knob to be gripped by a user and moved angularly about said knob axis to move the tongue from the extended position to the retracted position, at least one retaining member mounted on the knob for movement relative thereto between an extended position and a retracted position, each retaining member permitting angular movement of said knob when each retaining member is in the retracted position thereof, and preventing angular movement of said knob when each retaining member is in the extended position thereof, with each retaining member being moved along a respective line not intersecting with said knob axis, and a lock cylinder located in the knob and moveable angularly about said axis by a key to cause the movement of each retaining member between the positions thereof; and wherein said line is generally linear and spaced from said axis but generally perpendicular relative to said axis. Preferably, each retaining member includes a rack gear, and said part includes a pinion gear engaged with each rack gear so that upon angular movement of said part each retaining member is moved along the line thereof. Preferably, there are two retaining members, each retaining member being moved along a respective line, with the parts moved along generally parallel lines in opposite directions, with the members being spaced from said axis so as to be located on opposite sides thereof. BRIEF DESCRIPTION OF THE DRAWINGS A preferred form of the present invention will now be described, by way of an example only, with reference to the accompanying drawings wherein: Figure 1 is a schematic parts exploded isometric view of a knob assembly of a surface mounted lock; Figure 2 is a schematic end elevation of the knob assembly of Figure 1; Figure 3 is a further schematic end elevation of the knob assembly of Figure 1; Figure 4 is a schematic parts exploded isometric view of a surface mounted lock employing the knob assembly of Figure 1; and 2a Figure 5 is a further schematic parts exploded isometric view of the surface mounted lock of Figure 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the accompanying drawings, there is schematically depicted a surface mounted lock 10. The surface mounted lock 10 is intended to be mounted on the internal surface of a door and to engage a striker mounted on the adjacent door jamb. The lock 10 includes a base 12 that has a plurality of apertures 13 through which threaded fasteners pass to secure the base 12 to the door surface.
3 Slidably mounted on the base 12 is a carriage 13 that receives a tongue 14. The tongue 14 is moved along a linear path between an extended position engageable with the above-mentioned striker, and a retracted position clearing the striker so that the door may be moved to an opened position. 5 The carriage 13 includes a first carriage part 15 that is secured to a second carriage part 16 so they move in unison. Typically, threaded fasteners would pass between the parts 15 and 16 to secure them together. The part 16 is provided with guide passages 17 through which guide rods 18 pass to guide the carriage 13 to pass along a linear path. The lock 10 has an outer casing 19 that has a pair of apertures 20 through 10 which the rods 18 pass. The rods 18 also pass through apertures 21 and 22 and in particular threadably engage the apertures 22 to secure the casing 19 to the base 12 and to support the rods 18 so they in turn support the carriage 13 for movement as discussed. The part 16 has side walls 23 that slidably engage lateral projections of the tongue 14 to support the tongue 14 for linear movement relative to the carriage 13. The 15 projections 24 engage abutment 25 of the part 16 to locate the tongue 14 in the fully extended position. Springs 26 extend between the tongue 14 and spring locating projections 27 to urge the tongue 14 to move in the direction of the arrow 27, that is to move the tongue 14 to the fully extended position. The springs 26 located in passages 28 are of the tongue 14. The springs 26 are compressed and therefore continually urge the 20 tongue 14 into the direction 27. Mounted in slots 29 of the casing 19 are spring locators 30 that engage springs 31, with the springs 31 extending between the casing 19 and the carriage 13 to also urge the carriage 13 to move in the direction of the arrow 27. The springs 31 extend into passages 32 of the part 16. Again, the springs 31 are compressed so that the springs 31 25 continually urge the carriage 13 to move in the direction of the arrow 27. The carriage part 16 has a pair of elongated slots 33 through which is threaded fasteners 34 pass to engage threaded passages 35 in the casing 19. The threaded fasteners 34 are stationary relative to the casing 19, with the part 16 then moving relative to the fasteners 34 by movement of the fasteners 34 along the slots 33. The end extremities of 30 the slots 33 provide the limits of movement of the carriage 13. In that regard, it should be appreciated that the passages 34 are provided in elongated steps 36 that extend longitudinally in the direction of the arrow 27 and along which the carriage 13 slides.
4 As mentioned above, the springs 34 urge the tongue 14 to an extended position relative to the carriage 13. The springs 31 urge the carriage 13 to a position at which the tongue 14 projects from within the casing 19 to engage an adjacent striker. To move the tongue 14 to a retracted position there is provided a knob assembly 5 37. The knob assembly 37 includes a knob 38 that is gripped by a user and moved angularly about the axis 39. The knob 38 has a raised portion 40 that is gripped by a user. The knob 38 has inwardly extending projections 41 that engage a respective one of flanges 42 of the part 16. As the knob 38 moves about the axis 39 one of the projections 41 engages a respective one of the flanges 42 to cause the carriage 13 to retract the tongue 10 14. That is, angular movement of the knob 38 causes the carriage 13 to move in the opposite direction to the arrow 27 to retract the tongue 14 within the casing 19, thereby causing the tongue 14 to clear the striker and to provide for opening of the door. When the door is being closed and the tongue 14 engages the striker, the springs 35 are further compressed allowing the tongue 14 to retract within the carriage 13 thereby allowing the is tongue 14 to move at least over the striker to engage in an aperture in the striker. The knob assembly 37 has a central aperture 43 through which there extends a lock cylinder 44 that is key operated. By use of the key, the cylinder 44 is movable angularly about the axis 39. The cylinder 44 has internal projections 45 that engage a gear barrel 46. The gear barrel 46 provides a pinion gear 47. The gear 47 engages a pair 20 of retaining members 48. More particularly each retaining member 48 has a rack gear 49 meshing engaged with the pinion gear 47. Angular movement of the pinion gear 47 about the axis 39 causes movement of the members 48 in opposite directions 50. The arrows 50 extend generally normal relative to the axis 39. The members 48 each move along a line 76 (preferably linear). The lines 76 are generally parallel that does not intersect with the 25 axis 39, and is generally perpendicular relative thereto. The members 48 (and lines 76) are on opposite sides of the axis 39. The members 48 are movable from a retracted position (as shown in Figure 2) permitting movement of the knob assembly 38 about the axis 39, and an extended position (as shown in Figure 3) preventing movement of the knob assembly 38 about the 30 axis 39. When in the extended position the members 48 engage within recesses 51 provided by flanges 52 fixed to or formed integral with the casing 19. In operation of the above described knob assembly 38, a key is used to cause angular movement of the cylinder 44 about the axis 39 to move the members 48 between the about discussed 5 retracted and extended positions to release the knob 38 to retract the tongue 14 by movement of the carriage 13, or to prevent movement of the knob 38 so that the tongue 14 remains engaged with the striker. Slidably mounted on the casing 19 is a snib 53. The snib 53 includes a plate 54 5 slidably engaged with an internal surface 55 of the casing 19. Extending through the passage 56 of the plate 54 is a threaded fastener 57 that threadably engages an external snib member 58 that is gripped and moved by a user. The member 58 is moved in the direction of the arrow 59 and includes a projection 60 that is slidably located in an elongated recess 61 of the casing 19. By a user manipulating the snip member 58, the 10 snip member 58 is movable between two positions spaced in the direction 59. Attached to or formed integral with the plate 54 is a projection 62 that slidably engages the part 16 to maintain the tongue 14 retracting within the casing 19 and therefore prevent opening operation of the lock 10. However, the projection 62 is movable to provide for movement of the part 16 so that the tongue 14 can engage the is striker. A plate 66 having a central aperture 67 secures the tail guide 68 and barrel 46 together with cylinder 44 to the casing 19 while permitting angular movement thereof about the axis 39. A threaded fastener passes through the aperture 69 to engage in a threaded aperture in the casing 19. Extending from the plate 66 is a projection 70 that 20 engages the casing 19 to prevent angular movement of the plate 66 about the axis 39. Slidably mounted in the part 16 is a locking bar 71 (only illustrated in Figure 5). The bar 71 is slidably movable in a direction transverse of the direction 27 and includes a projection 72 that is selectively alignable with one of the slots 65 in the tongue 14. The particular slot 65 to be engaged is determined by the direction the lock 10 is moved into 25 engagement with the striker. The tongue 14 can be rotated about 1800 to adjust the "hand" of the door. When the projection 72 is aligned with a respective one of the slots 65, the tongue 14 can be retracted to permit closing of the door. However if the projection 72 is not aligned with a respective one of the slots 65, the tongue 14 is retained in the extended position relative to the part 16. 30 The bar 71 has a ramp projection 73 that is engaged by a trigger 74. The trigger 74 is slidably mounted on the part 16 and engages the striker. When the trigger 14 is moving to the extended position (not engaged with the striker), the portion 75 engages the projection 73 and moves the projection 72 to a position aligned with a respective one of 6 the slots 65. Accordingly the tongue 14 can be retraced. However when the trigger 74 is moved to a retracted position by engagement with the striker, the ramp portion 75 moves so as to "disengage" the projection 73 and therefore permitting movement of the bar 71 so that the projection 72 engages the tongue 14 preventing its movement. A spring 76 5 engages the part 16 and trigger 74 to urge the trigger 74 in the direction 27, engaging the striker. A spring (not illustrated) urges the bar 71 in a direction in which the projection 73 will engage the portion 75. The bar 71 is slidably mounted in slot 63 of the part 16. In operation of the above lock 10, typically the outside surface of the door would be provided with a lock cylinder having a "tail" extending inwardly through the door to io engage in the tail guide 68. From there it projects to engage in the end cavity 77 of the barrel 46. By turning the key, the members 48 can be retracted, with further angular movement of the key causing angular movement of the knob assembly 38 about the axis 39 so that the projections 41 engage the part 16 to retract the tongue 14. The key from the outside can also be manipulated to cause the members 48 to move to the extended 15 position to lock the knob assembly 38 from operation. The lock 10 is also operable from the inside. By use of a key engaging the cylinder 44, the barrel 46 can be rotated to move the members 48 to the retracted position. The knob 38 is then gripped and turned angularly so that a selected one of the projections 41 engages the part 16 to retract the tongue 14. The key may also be manipulated to 20 move the members 48 to the extended position so that the knob assembly 17 is locked. It should also be noted that when entering from the exterior, the lock 10 is operated to retract the members 48. Accordingly, the door can only be opened from the exterior when the lock 10 is in an "unlocked" configuration. This addresses the problem of a person inadvertently locking themselves on the inside of the door. More particularly 25 the lock 10 has a "safety release" function so that when unlocked the lock 10 from the outside, the lock 10 is activated so that the lock is also unlocked with respective to the inside. As best seen in Figure 1, the aperture 77 provides for a lost motion between the blade of the outside cylinder so that it may be returned to the withdrawal position without 30 moving the members 48 to the extended position.
7 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 many other forms.