AU2771800A - Locking device - Google Patents

Description

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority e Related Art: Name of Applicant: Sure Manufacturing Co. Ltd.

Actual Inventor(s): Address for Service:

S

PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: LOCKING DEVICE Our Ref: 603413 POF Code: 149/373487 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): -1r 2 LOCKING DEVICE Field of the Invention This invention relates to a locking device of the kind having a plurality of depressible push buttons, and which can be unlocked by depressing each of a predetermined group of those buttons. For convenience of description, the buttons of that group will be hereinafter referred to as operative buttons, and the other buttons of the device will be referred to as inoperative buttons. Each tumbler associated with an operative button will be referred to as an active tumbler, and each tumbler associated with an inoperative button will be referred to as an inactive tumbler.

The Prior Art A locking device of the foregoing kind is disclosed by Australian patent 561913.

The locking mechanism of prior locking devices of the foregoing kind :.00 15 typically include a plate-like slide mounted within the body of the device so as to S. be movable in a direction at right-angles to the direction of movement at the tumblers. Tumbler abutment lugs are provided on the slide in spaced apart relationship, and a tumbler is prevented from moving between the lock position and the lock release position when the slide is positioned such that an abutment lug intrudes into the path of travel of the tumbler. The slide is arranged to ";;*.influence operation of a door latch or bolt actuator, such as a turn knob. The turn knob cannot be rotated to withdraw the latch or bolt if part of any tumbler is located within the space between two adjacent abutment lugs.

It has been found that the security of locking devices of the foregoing kind can be breached in certain circumstances. A technique is available that permits a person to identify the operative push buttons and thereby enable deactivation of the locking device.

Another problem sometimes arises when the combination of the locking device is being changed. During such a change, an active tumbler may be substituted for a previously inactive tumbler and/or an inactive tumbler may be substituted for a previously active tumbler. In either case, the way in which a tumbler is located within the body determines whether the tumbler will be active or inactive, and it sometimes happens that a tumbler is located incorrectly. It may also happen that a tumbler is pushed too deeply into the body of the W:KATHY'SPECIIRN603413dOC 3 locking device during a change in combination, and that can interfere with the operation of the locking device.

It is an object of the present invention to provide a locking device of the foregoing kind that is less prone to a breach of security. It is a further object of the invention to provide a locking device of the foregoing kind that is constructed in a manner such as to minimise incorrect positioning of a tumbler.

A locking device according to the present invention is characterised in that it includes control means that functions to restrict the manner in which each tumbler is located within the body of the device. In one particular arrangement, the control means includes a plurality of guide grooves located within the body, and a cooperable guide projection provided on each tumbler. Each groove extends in the direction of movement of the tumblers, and each projection slidably locates within a respective one of the grooves so as to guide movement S'"i of the respective tumbler into and out of the lock release position. At least one 15 groove may be arranged differently to at least one of the other grooves so as to require the respective tumbler to be located within the body in a manner different to the manner in which at least one other tumbler is located within the e body.

Description of the Drawings An embodiment of the invention is described in detail in the following passages of the specification which refer to the accompanying drawings. The drawings, however, are merely illustrative of how the invention might be put into effect, so that the specific form and arrangement of the various features as shown is not to be understood as limiting on the invention.

In the drawings: Figure 1 is a side elevation of an example locking device incorporating an embodiment of the invention, and which is mounted on the outside surface of a door.

Figure 2 is a front elevation view of the locking device shown in Figure 1.

Figure 3 is a view similar to Figure 1 but showing the locking device and other door mounted components in cross-section.

Figure 4 is a rear elevation view of the locking device shown in Figure 1, with the back plate of the device removed to expose internal componentary.

W:AATHYMSPECrIRN603413.dOC 4 Figure 5 is an enlarged cross-sectional view taken along line A-A of Figure 4.

Figure 6 is a front elevation view of two tumblers, one of which is active and the other is inactive.

Figure 7 is a perspective view of part only of each of the tumblers shown in Figure 6.

Figure 8 is a perspective view showing the relationship between tumblers and a clearing member of the embodiment of the invention shown in the previous Figures.

Figure 9 is a front elevation view with parts removed to expose internal componentary of the locking device.

Figure 10 is a rear elevation view of the section of the locking device *"shown in Figure 9.

Figure 11 is a perspective view of part only of the section of the device 15 shown in Figure 9, and which has been sectioned along line B-B of Figure 9.

Figure 12 is an elevation view of the tumbler support base of the locking device shown in the previous Figures.

Figure 13 is a perspective view of part of the tumbler support base of Figure 12, and which has been sectioned along line C-C of Figure 12.

Detailed Description of a Preferred Embodiment In the example arrangement shown by Figure 1, a lock bolt 1 is movable beyond a front edge of a door 2 so as to be engageable within a cooperative cavity (not shown) provided in a door jamb (also not shown). The bolt 1 can be moved into or out of the door jamb cavity by operation of an operating mechanism 3 mounted on an inside surface of the door 2. That mechanism 3 includes a decorative cover plate 4 and a rotatable turn knob 5. The cover plate 4 as shown is of rectangular peripheral shape, but other peripheral shapes could be adopted.

A locking device 6 incorporating an embodiment of the invention is mounted on an outside surface of the door 2, and is operatively connected to the lock bolt 1 as hereinafter described. The device 6 includes a hollow body 7 and a rotatable turn knob 8. The body 7 and the cover plate 4 are preferably secured to their respective door surfaces by means of mounting bolts 9 (Figure W:KATHYASPECIRN6034 3.doC each of which cooperates in a suitable manner with both the body 7 and the cover plate 4.

It is preferred, as shown, that the turn knobs 5 and 8 are arranged substantially coaxial, and each is drivably connected to a respective end portion of an operating spindle 10 (Figures 3 and As best seen in Figure 4, the spindle 10 may be in the form of an elongate bar having a rectangular shape in transverse cross-section. In the preferred arrangement shown, one end of the spindle 10 is located within a boss 11 of the turn knob 5, and the other end is located within a pinion gear 12. The pinion gear 12 is positioned within the body 7 so as to be substantially coaxial with the turn knob 8, and is secured to the turn knob 8 so as to rotate therewith. The arrangement is such that the spindle 10 is able to rotate in response to operation of either of the turn knobs and 8, and the lock bolt 1 is moved into or out of the door 2 according to the ooooo direction of that rotation.

The spindle 10 may cooperate with the pinion gear 12 in any appropriate :manner. One suitable arrangement is shown by Figure 4, and includes a noncircular orifice 13 provided within the pinion 12, and within which the spindle is located. The shape of the orifice 13 is such that the spindle 10 is capable of limited rotation relative to the pinion gear 12. The purpose of that limited relative movement will be hereinafter described. As also hereinafter described, pinion gear 12 cannot be rotated by means of the turn knob 8 when the device 6 is in a locked condition.

In the example shown, the locking device 6 includes two rows of push buttons 14 arranged in spaced side by side relationship and extending in the direction of the longitudinal axis of the upwardly elongate body 7 (Figure 2).

Each push button 14 is accessible at the front of the body 7 and is able to be depressed so as to move towards the back of the body 7. A tumbler (Figures 3, 4 and 5) is associated with each push button 14, and in some circumstances responds to depression of the respective button 14 by moving towards the back of the body 7. Such movement of the preselected active tumblers 15A serves to release the locking mechanism 16 (Figures 3 and 4) of the device 6 as hereinafter described.

As best seen in Figures 3 to 5, the locking mechanism 16 includes an elongate clearing member 17 mounted within the body 7 so as to extend in the W:MATHY\SPECNRN603413.d0c longitudinal direction of the body 7. The clearing member 17 is supported by a central portion of a base member 20, and slidably locates within a guide groove 18 (Figure 5) formed in that central portion of the member 20 so as to be capable of relative movement in the longitudinal direction of the body 7.

Tumbler insertion passages 19 are formed through the member 20 for a purpose hereinafter described. The member 20 is sandwiched between a tumbler support member 22 and a back cover 23 of the body 7. The cover 23 closes an opening 7A (Figure 5) formed at the back of the body 7, and is removable when access to the mechanism 16 is required. The mechanism 16 also includes a slide 21 that is interposed between the members 20 and 22, and is arranged for relative movement in the longitudinal direction of the body 7.

Each tumbler 15 is located within a respective opening 22A provided in member 22, and each opening 22A is aligned with a respective one of the tumbler insertion passages 19.

15 The slide 21 is an elongate plate-like member having a length sufficient to extend over each of the tumbler insertion passages 19. As previously mentioned, the slide 21 is arranged for relative movement in the longitudinal direction of the body 7. In the arrangement shown, the slide 21 is urged into a lowermost or rest position, (Figure 4) by two compression springs 24, but other biasing means could be used for that purpose. Each spring 24 is interposed 0 *between an upper end of the slide 21 and a top wall of the body 7. An elongate opening is formed through the central portion of the slide 21, and each longitudinal edge of that opening is formed by an alternating series of tumbler abutments 26 and recesses 25. That is, a recess 25 separates each two adjacent abutments 26 at the same edge of the opening.

Biasing means presses the slide 21 against an under-surface of the member 22, which is the normal position of the slide 21, and allows the slide 21 to be moved, under pressure, towards the back of the body 7. In the example arrangement shown, that biasing means includes a plurality of thrust pins 28 and a coil compression spring 27 associated with each pin 28 (Figure Each spring 27 acts between a surface of the member 20 and a head of the respective pin 28, and presses the head of the pin 28 against the under-surface of the slide 21. That is, pressure applied to the slide 21 by a rearwardly moving tumbler 15 causes the slide to be moved, in the same direction as the tumbler W:A(ATHYSPEC1JRN603413.dOC out of its normal position. The arrangement is such that a tumbler 15 is able to be moved towards the back of the body 7 even in circumstances where that tumbler is engaging an abutment 26 of the slide 21. That has the advantage of making it difficult to distinguish, by feel alone, between active and inactive tumblers The clearing member 17 is provided with a plurality of bifurcated tumbler retention springs 29 (Figure Each spring 29 is secured to the body of the member 17 at a preselected position so as to be movable with that body relative to the device body 7. As shown by Figure 8, the springs 29 are spaced apart in the longitudinal direction of the member 17. Each spring 29 is operable to releasably hold a tumbler 15 in the lock release position, and the manner of that retention is illustrated in Figure 5 in relation to the active tumbler 15A. As also shown by Figure 5, the clearing member 17 is disposed between the two rows of push buttons 14 so that one arm of a spring 29 can act on a tumbler 15 of 15 one of the rows, and the other arm of the spring 29 can act on a tumbler 15 of the other row.

As best seen in Figure 4, the clearing member 17 is resiliently urged downwards towards a lowermost position by means of a compression spring The spring 30 acts between an upper end of the clearing member 17 and a top wall of the body 7. The arrangement is such that the clearing member 17 and ***the slide 21 are able to move independent of one another in the longitudinal direction of the body 7.

The pinion gear 12 meshes with a sector gear 32 that is mounted for rotation about the axis of a shaft 31. The sector gear 32 is positioned between the pinion gear 12 and the slide 21, and at least one stop pin 33 is fixed to the sector gear 32 so as to be engageable with the lower end of the slide 21. As shown by Figure 4, the pin 33 is located at one side of the shaft 31, and is arranged substantially parallel to the axis of the shaft 31. A hole 33A is formed in the sector gear 32 at the other side of the shaft 31, and is adapted to receive a second pin 33 if required. Alternatively, the hole 33A enables a single pin 33 to be located on either side of the shaft 31, according to requirements.

When the locking device 6 is in the locked condition, part of at least one tumbler 15 is located within a recess 25 of the slide 21, and thereby prevents movement of the slide 21 upwards from the position shown by Figure 4. It is W:AKATHYSPECRIRN603413.doc 8 then not possible to rotate the sector gear 32 because of engagement of the pin 33 with the lower end of the slide 21. As a result, it is not possible to rotate the pinion gear 12 through operation of the turn knob 8, and it is therefore not possible to withdraw the lock bolt 1 by operation of the turn knob 8.

When the locking device 6 is in the unlocked condition, no part of any tumbler 15 intrudes into any one of the recesses 25. Upward movement of the slide 21 is therefore possible, and such movement occurs in response to rotation of the turn knob 8 because that rotation causes the pin 33 to rise and press against the lower end of the slide 21.

As best seen in Figures 5 and 6, each tumbler 15 has, at one side edge, a locking part 34 and a release recess 35. A stop shoulder 36 is provided at the opposite side edge of the tumbler 15. The stop shoulder is engageable with a detent part 29A of the spring 29, as shown by Figure 5 in relation to the active tumbler 15A. It will be also evident from Figure 5 that when the active tumbler 15 15A is in the lock release position, the recess 35 of that tumbler 15A is positioned so that the tumbler 15A does not impede longitudinal movement of the slide 21. On the other hand, when the tumbler 15A is in the lock position, the locking part 34 of the tumbler 15A will be located in one of the slide recesses 25, and as a consequence will prevent longitudinal movement of the slide 21.

In the particular arrangement shown, a lower end portion of each active tumbler 15A is located within a cavity 37 formed within the inner surface of the back cover 23, when that tumbler is in the lock release position (Figure A return spring 38 acts between the tumbler 15A and the base of the cavity 37 so as to urge the tumbler outwards towards the lock position, which position corresponds to the position of the inactive tumbler 15B as shown by Figure In the situation as shown by Figure 5 however, the spring 29 prevents the active tumbler 15A being moved into the lock position.

As will be apparent from Figures 5 and 6, the configuration of the inactive tumbler 15B differs from that of the active tumbler 15A. In particular, the position of the locking part 34 of the inactive tumbler 15B corresponds to the position of the release recess 35 of the active tumbler 15A, and the position of the release recess 35 of the inactive tumbler 15B corresponds to the position of the locking part 34 of the active tumbler 15A. Thus, the inactive tumbler W:\(ATHYSPEC IRN80343.doc 9 does not impede longitudinal movement of the slide 21 when at the outermost position (as shown by Figure 5) which corresponds to the lock position of the tumbler When an inactive tumbler 15B is pressed downwards into what would be the lock release position of an active tumbler 15A, the locking part 34 of the tumbler 15B is located within a recess 25 of the slide 21. Longitudinal movement of the slide 21 out of the position shown by Figure 5 is then prevented because of engagement between an abutment 26 of the slide 21 and the locking part 34 of the tumbler It is preferred, as shown, that each push button 14 has an internal cavity opening towards the back of the body 7. A push button return spring 39 acts between the base of the aforementioned cavity and a projecting part 40 of the member 22. Other arrangements are clearly possible. When a button 14 is depressed to place an associated tumbler 15A in the lock release position (as o* 15 shown by Figure release of finger pressure on the button 14 allows the spring 39 to urge that button back into the outer position (as shown by Figure That outward movement of the button 14 however, occurs independent of the tumbler 15A which remains in the lock release position because of the retention influence of the spring 29.

In the particular embodiment shown by Figure 2, the numerals to **and the alphabetic characters and are printed or otherwise marked on the outer end surface of respective push buttons 14. Each button 14 other than that marked is associated with an active or an inactive tumbler The button marked is associated with a clearing tumbler 41, which is shown by Figure 8. As will be apparent from Figure 8, the clearing tumbler 41 is provided with a sloping cam element 42.

Depression of the button causes the clearing tumbler 41 to move towards the back of the body 7, with the result that the cam element 42 presses against an inclined cam surface 43 of the clearing member 17. As the tumbler 41 is moved further towards the back of the body 17, coaction between the cam element 42 and the cam surface 43 causes the clearing member 17 to move upwards against the action of the spring 30. The clearing member 17 eventually reaches a position at which the springs 39 are moved beyond their respective tumblers 15 and are no longer capable of maintaining a retaining W:XATHYkSPECIRN603413.doc influence on those tumblers. Thus, any active tumbler 15A previously held in the lock release position will be freed to move into the lock position under the influence of its respective spring 38. Similarly, any inactive tumbler previously held in the lock position, will be freed to move into the lock release position under the influence of its respective spring 38.

The locking device 6 may include means for returning the turn knob 8 to an initial stand-by position when the bolt 1 has been moved to protrude from the edge of the door 2. In the arrangement shown, that return means includes a slide plate 45 arranged to engage the side of the pin 33 opposite to that engaged by the lower end of the slide 21 (Figure The plate 45 is urged upwards into engagement with the pin 33 by a pair of compression springs 44.

As shown by Figure 4, the plate 45 may be of inverted U shape so as to provide downwardly opening recess for receiving the pinion gear 12. The non-circular.

shape of the orifice 13 in the pinion 12, allows the necessary relative rotation of oO .oo* 15 the spindle 10 when the turn knob 8 is being returned to the stand-by position.

Each tumbler 15 may be colour coded, or otherwise marked, to enable convenient identification of active and inactive tumblers respectively. By way of example, such marking may be provided on the end surface 46 (Figures 5 and 6) of a tail portion 47 of each tumbler 15. In the arrangement shown, each tail portion 47 is located towards the back cover plate 23, and is intended to form a ***locater for an end of the respective tumbler biasing spring 38.

It is preferred that the opposite longitudinal side edge portions of the back cover plate 23 are located within respective recesses 51 (Figure i provided in the under surface of the member 20. It is further preferred that each of the side edge portions of the plate 23 engages against the base surface of the respective recess 51 so that a space of predetermined depth is available beneath each tumbler 15 to accommodate downward movement of the tumbler The depth of that space is preferably predetermined so that excessive downward travel of the tumblers 15 is prevented. It is also preferred that the outer surface of the cover plate 23 is substantially flush with the back edge of each side wall of the body 7 as shown by Figure Inspection openings 48 (Figure 5) may be formed through the cover plate 23. The openings 48 are preferably positioned to enable inspection of the tumblers 15 such that correct positioning of the tumblers can be confirmed. The W:U(ATHYSPECPIRN603413.dOC 11 openings 48 also enable inspection of colour coding or other distinguishing marks provided on the tumbler tail portions 47. Viewing of the tumblers may be facilitated if the openings 48 are formed so as to enlarge progressively from the inside to the outside of the cover plate 23, as shown by Figure Figures 9 to 11 show detail of the previously mentioned base member Recesses 55 and 56 provided at the upper and lower ends respectively of the member 20, cooperate with respective parts of the body 7 to facilitate correct location of the member 20 within that body. An aperture 57 is formed through the member 20 to allow passage of the spindle 10, and another aperture 58 is formed through the member 20 to allow passage of the sector gear shaft 31. An arc shaped slot 59 is provided on each side of the aperture 58 to receive the pin 33, or a respective one of the pins 33 if two are provided, and to provide a guide slot for that pin.

As shown by Figure 10, numerals and alphabetic characters 15 corresponding to those provided on the push buttons 14, may be provided on a suitable surface of the member 20. Each such numeral and alphabetic character is located adjacent a respective one of the tumbler insertion passages 19, and in each case the numeral or alphabetic character applied to an passage 19 corresponds to the numeral or alphabetic character applied to the push button 14 that acts on the tumbler 15 associated with that passage 19. Figure shows the numerals and alphabetic characters on a rearwardly facing surface of the member 20, and consequently they appear to be positioned, left to right, differently to the corresponding push buttons 14 as shown by Figure 2.

As shown by Figures 9 and 11, a block-like section 62 of the member separates each two adjacent passages 19 of the same vertical row of passages 19. The sections 62 are provided at the forwardly facing side of the member and are relatively positioned so that the width of each passage 19, in the top to bottom direction of the member 20, is such as to provide an accurate guide for the tumbler 15 received therein.

It is a feature of the locking device 6 according to the invention that it is provided with control means 68 that restricts the manner in which each tumbler can be located within the body 7. In the particular arrangement shown, the control means 68 includes a guide projection 66 provided on each tumbler and a guide groove 63 provided within the body 7 and arranged to slidably W:W.ATHYASPECRN603413.doc 12 receive a respective one of the projections 66. Each groove 63 extends in the direction in which the tumblers 15 travel when moving between the lock position and the lock release position.

As shown by Figure 9, it is preferred that each groove 63 is formed in either an upper side or a lower side of a respective one of the sections 62.

Each groove 63 is thereby associated with a respective one of the passages 19.

It is also preferred that each groove 63 communicates with a respective tapered cavity 64 provided at the rearwardly facing side of the member 20. The cavities 64 are arranged to facilitate insertion of the tumblers 15 into the body 7 during assembly of the locking device 6.

One form of guide projection 66 for each tumbler 15 is shown by Figures to 7. According to that example, each projection 66 is a cylindrical member located substantially central in the transverse width of the tumbler 15, and extends upwardly from one of the broad surfaces of the tumbler 15. It will be 15 understood that the projection 66 may have a shape other than cylindrical. The projection 66 may be formed by a pressing or punching operation such that it is an integral part of the tumbler As will be seen from Figures 9 to 11, a guide groove 63 is provided at one side only of each passage 19. Also, there is variation in the side at which the groove 63 is located. In the example shown by Figures 9 and 10, the groove 63 is located at the upper side of each passage 19 in one row of passages 19, and is located at the lower side in the other row of passages 19.

Other arrangements are clearly possible. But irrespective of the arrangement "i adopted, each groove 63 and the cooperating tumbler projection 66 must be aligned in order for the tumbler 15 to be capable of insertion into the mechanism 16. Incorrect insertion is not possible.

In the particular arrangement shown, the construction of each tumbler conforms to a particular standard. That is, when the tumbler 15 is viewed from the side from which the projection 66 extends, the locking part 34 and the release recess 35 are located along the right-hand edge of the tumbler whereas the stop shoulder 36 is located at the left-hand edge of the tumbler (see Figure 6, tumbler 15A). That particular arrangement, coupled with the positioning of the groove 63 as shown by Figures 9 to 11, has the automatic W:U(ATHYkSPECNRN603413.doc 13 consequence that the stop shoulder 36 of every tumbler 15 is located adjacent the clearing member 17 so as to be engageable by a spring 29.

The disposition of the clearing tumbler 41 is controlled in a similar manner so that it is positioned for appropriate cooperation with the clearing member 17 (Figure 8).

As shown by Figure 5, and as previously described, the tumbler support member 22 overlies the member 20. Tumbler insertion openings 22A (Figures 12 and 13) are formed through the member 22 at positions corresponding to those of the underlying passages 19. Thus, as best seen in Figure 5, each opening 22A is aligned with a respective passage 19 to form a continuation of the guide passage for a respective one of the tumblers 15. As shown by Figure 12, two of the previously described projecting parts 40 are associated with each opening 22A. The two parts 40 are located on respective opposite sides of the S"opening 22A, which are the upper and lower sides when the member 22 is in its 15 normal disposition Each part 40 is preferably stepped downwardly from a central portion as shown by Figure 5 so as to provide a locater for the spring 39.

A spacer element 70 is provided at the outer side of each opening 22A, and another spacer element 71 is provided between adjacent openings 22A located in different vertical rows of those openings (Figures 12 and 13). Each element 70 and 71 extends a predetermined distance outwardly from a planar surface of the member 22. The elements 70 and 71 are arranged to engage against an inner surface of the front wall of the body 7 so as to establish the correct depth of the assembly formed by the members 20 and 22. As shown by Figure 5, the members 20 and 22 are held together in face to face relationship.

The elements 70 and 71 also act as guides for movement of the tumblers The parts 40 are not provided with grooves corresponding to the grooves 63 of the member 20. As will be seen from Figure 5, the tumblers 15 do not move outwards to an extent such as to warrant the provision of such grooves.

The front to back depth of the member 20 is sufficient to accommodate the full extent of travel of the tumbler projection 66. In addition however, the fact that the parts 40 do not have grooves corresponding to the grooves 63 enables the undersurface 22B of the member 22 to act as a stop face for the tumblers It follows that forward travel of each tumbler 15 away from the back cover plate 23 is limited by engagement between the tumbler projection 66 and the W:MKATHYSPECIRN60343.doc 14 surface 22B. It is therefore not possible to insert the tumblers 15 too far forwards when inserting them through the back of the body 7 during assembly of the locking device 6.

As shown by Figure 12, an opening 73 is formed through the member 22 to allow passage of the sector gear shaft 31.

A locking device as described has a number of benefits by comparison with prior devices of the same general kind. The arrangement of the device is such that manufacture is simplified. By way of example, formation of the tumbler guide grooves 63 is a relatively simple matter, and the process is further simplified by the fact that those grooves need to be formed in one member only.

It is a further advantage that any of the push buttons 14 can be selected to cooperate with either an active tumbler 15A or an inactive tumbler Alteration of the combination of the device is a relatively simple matter.

15 The locking device particularly described and shown in the accompanying drawings is open to substantial variation. By way of example only, more than one clearing member 17 may be employed, and in that case it may be possible or convenient to have all guide grooves 63 at the same side of their respective passages 19. Furthermore, a key operated lock could be substituted for, or associated with, the turn knob 8.

Various alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without .departing from the spirit or ambit of the invention as defined by the appended claims.

W:'KATHYSPECKIRN603413.doc

Claims (14)

1. A locking device including a body, a plurality of depressible push buttons accessible at a front of the body, tumblers contained within the body and each being located within a respective guide passage so as to be movable therein between a lock position and a lock release position, each of a predetermined group of said tumblers being responsive to depression of a respective one of said push buttons so as to adopt said lock release position, and control means associated with each said passage and preventing location of a said tumbler within the respective said passage unless the tumbler has a particular disposition relative to that passage, the arrangement being such that said locking device adopts an unlocked condition when each said tumbler is in the said lock release position.

2. A locking device according to claim 1, wherein said control means includes a guide groove formed within a side of each said passage and 15 extending in the direction of said movement of the respective said tumbler, and a cooperable guide projection provided on each said tumbler and arranged to be slidably located within a said groove.

3. A locking device according to claim 2, wherein the position of the said groove of at least one said passage is different to the position of the said groove of at least one other said passage. A locking device according to claim 3, wherein the groove of said one passage is located at one side of that passage, and the groove of said other passages located at another side of that passage. A locking device according to any one of claims 2 to 4, including two parallel and laterally spaced rows of said passages, each said passage having an upper side and a lower side, each said guide groove within one said row is located at said upper side of the respective said passage, and each said guide groove within the other said row is located at said lower side of the respective said passage.

6. A locking device according to any one of claims 2 to 5, wherein each said passage extends through each of two members located within said body, a first one of said members is located adjacent the front of said body, a second one of said members is located adjacent the back of said body, and each said guide W:ATHY\SPECN RN603413.doc groove is formed in that part of the respective said passage extending through said second member.

7. A locking device according to any one of claims 2 to 6, wherein a stop face is provided at an end of each said guide groove so as to be engageable by a said guide projection and thereby limit movement of the respective said tumbler towards said front of the body.

8. A locking device according to claim 7 when appended to claim 6, wherein said stop face is formed by a surface of said first member.

9. A locking device according to any preceding claim, wherein each tumbler within said predetermined group is an active tumbler, each tumbler within another group of said tumblers is an inactive tumbler, and each said inactive tumbler adopts said lock position in response to depression of the respective said push button.

10. A locking device according to any preceding claim, wherein at least one 15 clearing member is located within said body and is operable to cause the tumblers of said predetermined group to return from the lock release position to the lock position, and to simultaneously cause other said tumblers to return from the lock position to the lock release position. S.i.

11. A locking device according to claim 10, including a clearing tumbler and a push button operable to move said clearing tumbler into engagement with said clearing member and thereby operate said clearing member.

12. A locking device according to claim 11, wherein a cam element is provided on said clearing tumbler, a cam surface is provided on said clearing member, and said clearing member operates in response to coaction between said cam element and said cam surface.

13. A locking device according to any preceding claim, including a slide mounted within said body so as to be movable into and out of a rest position, said slide movement being in a direction transverse to the direction of movement of said tumblers, said slide is prevented from moving out of said rest position when any one of said tumblers is in said lock position, and said locking device cannot be unlocked while said slide remains in said rest position.

14. A locking device according to claim 13, wherein said slide is operative, when not in said rest position, to prevent movement of each said tumbler from the lock release position to the lock position. W:U(ATHYSPEClIRN63413.dOC A locking device according to claim 14, wherein said slide is mounted within said body for relative movement in the direction of movement of said tumblers, and biasing means resiliently urges said slide towards the front of said body so that said slide adopts a normal position relative to said body, the arrangement being such that said normal position can be maintained while said slide moves into or out of said rest position, and when said slide is not in said rest position it moves out of said normal position in response to pressure applied by a said tumbler being moved away from the front of said body.

16. A locking device according to claim 15, wherein said slide biasing means includes a plurality of thrust pins arranged in laterally spaced relationship, and a spring associated with each said pin and arranged to urge the respective said pin into engagement with a surface of said slide.

17. A locking device substantially as herein described with particular reference to the embodiment shown by the accompanying drawings. egos DATED: 13 April, 2000 :PHILLIPS ORMONDE FITZPATRICK Attorneys for: SURE MANUFACTURING CO. LTD. 0 W:KATHY\SPEC'IRN60343.dOC