GB2146691A

GB2146691A - Variable mechanical combination lock

Info

Publication number: GB2146691A
Application number: GB08420513A
Authority: GB
Inventors: Gianpaolo Rocchelli
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-08-12
Filing date: 1984-08-13
Publication date: 1985-04-24
Also published as: GB2146691B; GB8420513D0

Abstract

A mechanical combination lock comprising a plurality of rotatable selectors (3) for setting the combination and for locking and unlocking the lock, each selector being provided with at least one cam disc (6) and a bolt (11) which is displaceable relative to the selectors and co-operates with the at least one cam disc to secure the lock in its locked position, wherein each selector is integrally formed with the at least one cam disc (6) each cam disc being spaced from, but parallel to, a head portion of the selector associated therewith the bolt being slidably coupled to each rotatable selector (3) so that the bolt is secured to an object (1) to be locked by the intermediary of at least one of the cam discs (6) and each selector including means for altering the combination which permits the bolt to be released from its locked position. <IMAGE>

Description

SPECIFICATION Variable mechanical combination lock The present invention relates to a variable mechanical combination lock and more particularly to a lock which may be used for securing of small strongboxes, deed boxes, mailboxes, document cases, minute books or private or confidential diaries or files.

Combination locks are, of course, weil known. For example, in British Patent Specification No. 777,483, a combination lock is disclosed. However, it comprises a large number of components and, once assembled, has a considerable thickness which prevents its use in places where compactness of the lock is required.

The present invention seeks to provide a lock of simple construction which is easy to assemble. Furthermore, the invention seeks to provide a combination lock having fewer components than most, if not all, known combination locks and which does not necessitate the use of threaded members, pins or similar device in order to permit the attachment of the lock to the object which is to be locked.

In a further aspect the present invention seeks to provide a lock in which the unlocking or correct combination may be set and/or altered by the user at any time.

According to the present invention, there is provided a mechanical combination lock comprising a plurality of rotatable selectors for setting the combination and for locking and unlocking the lock, each selector being provided with at least one cam disc and a bolt which is displaceable relative to the selectors and co-operates with the at least one cam disc to secure the lock'in its locked position, wherein each selector is integrally formed with the at least one cam disc, each cam disc being spaced from, but parallel to, a head portion of the selector associated therewith the bolt being slidably coupled to each rotatable selector so that the bolt is secured to an object to be locked by the intermediary of at least one of the cam discs and each selector including means for altering the combination which permits the bolt to be released from its locked position.

Certain embodiments of a lock in accordance with the present invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows, separately, a perspective view of a bolt and a selector forming part of a lock in accordance with the present invention, Figure 2 shows a perspective view of a partially-assembled lock in accordance with the present invention and also shows a portion of a strongbox, briefcase or the like on which the lock is mounted, Figure 3 shows a cross-sectional view taken along the line Ill-Ill in Fig. 2, Figures 4 and 5 show, respectively, perspective views from above and below of a fully-assembled lock in accordance with the present invention.

Figure 6 shows a cross-sectional view taken along the line VI-VI in Fig. 5, Figure 7 shows a view of a modification of the lock shown in Figs. 1 to 6 in which the bolt of the lock has an extended movement path.

Figure 8 shows a perspective view similar to Fig. 1 of a modified embodiment of a lock in accordance with the present invention, Figure 9 shows an underneath view of a bolt and selectors of the device shown in Fig.

8, and Figure 10 shows a longitudinal cross-sectional view of the lock shown in Fig. 9.

In the drawings, there is shown a combination lock 2 which is fitted to an object 1, such as a strongbox, briefcase or file, the contents of which are intended to remain confidential.

The lock 2 is of the type which comprises a plurality of selectors 3 located externally of the object 1 and which can only be opened by rotating each individual selector 3 into a predetermined position. The object 1 may thus be the lid or door of a container, box or document case or even the cover of a book, or diary.

Each selector 3 comprises a disc 4 which is integrally formed with a cylindrical pin or shank 5. Also integrally formed with the disc 4 and shaft 5 is at least one further disc 6 spaced apart from the disc 4. The disc 6 is provided with a radially extending recess 7 to define a cam surface.

The disc 4 has a greater diameter than cam disc 6, which latter, in turn, has a greater diameter than the pin or shank 5. An axially extending bore 5' is formed in the pin 5. In the bore 5', a rod 8 is located. One end of the rod 8 is attached, as shown in Fig. 6, to a plate 9 which is inserted into a correspondingly-shaped recess 4' formed in the head of the disc 4. The other end of the rod 8 is biassed by a spring 10 located around the rod 8 and which is axially displaceable so that the plate 9 is normally located in the recess 4'.

The rod 8 and the plate 9 can be both axially and rotatable with respect to the disc 4 and the pin shank 5 so as to alter the location of reference marks 1 6 provided on the plate 9 with reference to an index mark.

The lock further includes a securing bolt 11 which is coupled with the shanks or pins 5 of the selectors 3 and which can be displaced manually by appropriately sliding a lug 11'.

The lug 11' is removably mounted by means of a bayonet fitting. The bolt 11 acts in conjunction with the cam discs 6 to lock and unlock the device to which the lock is fitted.

For this purpose, the bolt or spring lock 11 has apertures or recesses 1 2 formed therein which receive the selectors 3. The lock 11 also has rectangular slots 1 3 formed therein in order to allow the bolt to move horizontally with respect to the shanks or pins 5 of the selectors 3.

In the embodiments shown in Figs. 1 to 7, each aperture 1 2 in the bolt 11 is produced by cutting a disc 21 from the bolt in the appropriate location but leaving the disc 21 attached to the bolt by a resilient connecting portion 22. This can be seen most clearly in Figs. 1 to 3. A radially extending recess or slot 23 is formed in each disc 21 which slot 23 opens towards and is aligned with the adjacent rectangular slot 1 3. The slots 1 3 and 23 thus jointly form a slot which receives the shank 5 of a selector 3 and which permits the bolt 11 to be axially displaced with respect to the selectors and, when appropriate to restrict such movement.

The apertures 12 in the bolt 11 have a diameter which is slightly greater than the diameter of the discs 6 whilst the slots 1 3 and 23 have a width which is slightly greater than the diameter of the pins or shanks 5 of the selectors.

Projections 14 which are designed to co-act with the profile of the cam discs 6 and which become located in the radial slots 7 of the discs 6 where these are aligned with the projections 14, are formed at the ends of the rectangular slots 1 3 remote from the apertures 12. It is only when the projections 14 are located in the slots 7 that the bolt 11 can be moved into the release position.

For the purpose of mounting and simultaneous assembling the lock, it suffices to provide a support which can be mounted on the object 1 to be locked or, failing this, the object 1 itself with apertures 1 5 having a diameter which is slightly greater than that of the cam discs 6. The selectors 3 are then inserted into the apertures 1 5 so that discs 4 are exposed for operation. The discs 4 simultaneously cover the apertures 1 5 to hide them.

The bolt 11 is then connected by a bayonet-type attachment to the cam discs 6 which project from the inward4acing support 1 or the object which is to be locked. This coupling is brought about by inserting the cam discs 6 into the apertures 1 2 in bolt 11 by movement in an axial direction followed by longitudinal movement of the bolt with respect to the selectors (or vice versa). The insertion of the discs 6 into the apertures 1 2 is made possible by the displacement of discs 21 due to the corresponding resilient connecting portions 22. There is thus made an attachment to the bolt 11 as is illustrated in Figs. 2 and 3 of the drawings.If the discs 6 are then moved together towards the slots 1 3 with respect to the discs 21, the discs return to their positions in which they lie in the plane of the bolt 11 and thus in a plane between the cam discs 6 and the discs 4. This prevents the selectors 3 from being released.

The selectors 3 and the bolt 11 are thus mutually locked together and the support 1 of the object which is to be locked lies between the discs 4 of the selectors and the bolt 11.

The shanks or pins 5 of the selectors fit into the rectangular slots 1 3 and 23. In this way, the selectors 3 may be rotated to set and disarrange the combination by rotating the setting discs 4. In addition, the bolt 11 can be displaced axially between its locked and unlocked positions and is guided during such displacement.

The presence of the discs 21 corresponding to the apertures 1 2 in the bolt and of the recesses 23 in the discs makes it possible to reduce the overall length of the bolt while still ensuring that it has sufficient travel between its locked and unlocked positions.

However, as illustrated in Figs. 8 to 1 0 of the drawings, the apertures 1 2 in the bolt 11 may be throughbores, which means that the discs 21 shown in the embodiments of Figs.

1 to 6 are not present and that there is no resilient strip 22. Moreover, each selector may carry a plurality of discs 9 which extend parallel to but are spaced apart from one another. In such a case, each disc 6 is provided with a radial slot 7.

In this embodiment, the mounting of the lock is again achieved by providing the object 1 with apertures 1 5 having a diameter which is slightly greater than that of the cam discs 6. The selectors 3 are then inserted into the apertures 1 5 so that the setting discs 4 are exposed to the exterior and both close and conceal the apertures 1 5.

The spring lock or bolt 11 is then coupled with the portions of the selectors 3 protruding into the interior of the object 1. This coupling is achieved by first passing the pins or shanks 5 having the cam discs 6 integrally formed therewith into the apertures or slots 1 2 in the bolt 11 and by then moving the bolt axially so that pins or shanks 5 pass into the oblong slots 1 3 in the bolt. The bolt 11 is thus engaged with a stop which prevents axial coincidence between apertures or slots 1 2 and the cam discs 6 so as to prevent accidental release of the lock from the object 11.

The bolt 11 is located, as can best be seen in Fig. 1 0 between a cam disc 6 of each selector 3 and the object 1 which is to be locked or unlocked and acts against the discs 4 so as to secure the selectors to the object 1 in an axial direction. By using the selectors 3 shown it is possible for the device to be utilised on any thickness of object 1 which requires to be locked. In each case, the bolt merely needs to be engaged with one of the cam discs of each selector. If desired the surplus portion of the shank 5, together with any surplus discs 6 projecting towards the interior of the object 1 may be cut off and removed. The lock is therefore of wide-ranging applicability without the necessity for changes in the manner of its assembly or operation.

In each of the embodiments described, the bolt 11 may be provided with a resilient portion 24 which acts as a spring and which is capable of moving and which automatically biasses the bolt into a given usually the locked position. The spring portion, which may be substantially sinusoidal as shown can be so dimensioned so that it lies within the thickness and the width of the bolt and does not necessitate the dimensions of the latter being altered. Advantageously, in such a case, the lug 11' for operation of bolt 11 may be connected to a resilient portion 1 9 fashioned from the bolt 11.

The resilient portion 1 9 does not prevent normal manual movement of the bolt but is provided to absorb excessive forces applied to lug 11' if an attempt is made to force open the lock without setting the correct combination. The absorption of such forces by the resilient portion 1 9 prevents the lock from breaking and also prevents the bending or breaking of the projections 1 4 which bear against the edges of the cam discs 6 when the lock is in its closed position.

Engaging notches 25, which act in conjunction with the projection 14 formed at the ends of the slots 1 3 without, however, permitting the bolt 11 to be moved into its unlocked position, may be provided on the periphery of cam discs 6 of the selectors 3. The object of these notches 25 is to confuse a person who is attempting to ascertain the exact position of the selectors which permit the projections 1 4 to enter the radial slots 7 without knowing the correct combination.

In the embodiment shown in Fig. 7, the disc 6 of each selector 3 is provided with a radial slot 7' which extends across almost the entire diameter of the disc 6 for receiving a projection 14' of a corresponding length. This embodiment makes it possible to extend the travel of the bolt for any desired purpose without making it necessary to increase the diameter of the selector and of the cam disc.

A slot of lesser width which does not permit the passage of the projection thereinto to complicate the search for the correct combination may be formed at one end of the slot 7'.

The lesser width slot may be provided in addition to the radial slots or recesses 25, if desired.

Numbers and/or letters of the alphabet and/or various symbols 1 6 are provided on the plate 9 of each selector 3 and the correct number, letter or symbol on each selector 3 must be aligned with a reference mark or marks 1 7 on the object 1 to enable the lock to be opened.

In order to lock the object 1, it is sufficient to move bolt 11 manually until it engages the end with an engaging portion. The selectors 3 are then randomly rotated with respect to the predetermined combination which opens the lock. In this condition, the projections or pins 14 of the bolt 11 engage the edge of the cam discs 6, thus preventing any rearward movement of the bolt 11.

In order to undo the lock, it is necessary to know and set the correct combination by rotating each of the selectors 3 into its correct position. Only when this has been done are all of the radial slots 7 of the cam discs 6 aligned with the projections or pins 14 of the bolt 11 and the bolt can be withdrawn.

As mentioned hereinbefore, the lock of the present invention also offers the possibility of altering and resetting, at will, the combination which permits the object 1 to be opened. In order to achieve this, it is sufficient to move the rod 8 axially, against the force of the spring 10, until the plate 9 projects from recess 4' in the setting disc. The plate is then rotated so as to alter its position both with respect to the radial slot 7 in the cam disc 6 and with the reference mark 1 7. When the rod is released plate 9 returns into the recess 4' in setting disc 4 and rotates integrally therewith when the selector is set and disarranged.

The connection between the plate 9 and setting disc 4 may be assisted by means of locking lugs 1 8 made in one of these two members and engaging in the other, as is shown in Fig. 6. As an alternative, the plate 9 and the corresponding recess 4' in the setting disc 4 may be of complementary polygonal shapes so that one cannot rotate with respect to the other when they are fitted together.

Finally, it should be noted that reference marks and/or indicators corresponding to those provided on the selectors and/or in association therewith may also be provided within object 1 so that a visual check of the correct combination is available.

Claims

1. A mechanical combination lock comprising plurality of rotatable selectors for setting the combination and for locking and unlocking the lock, each selector being provided with at least one cam disc, and a bolt which is displaceable relative to the selectors and co-operates with the at least one cam disc to secure the lock in its locked position, wherein each selector is integrally formed with the at least one cam disc, each cam disc being spaced from, but parallel to, a head portion of the selector associated therewith the bolt being slidably coupled to each rotatable selector so that the bolt is secured to an object to be locked by the intermediary of at least one of the cam discs and each selector including means for altering the combination which permits the bolt to be released from its locked position.

2. A lock as claimed in claim 1, wherein each selector includes a disc or head portion, a cylindrical pin or shank and a cam disc integrally formed with one another, the cam disc having a radial slot formed therein, the bolt having apertures formed therein, the portion of the bolt removed to produce the apertures being disc-shaped and remaining connected to the bolt by means of a resilient connecting portion the bolt also having substantially rectangular slots formed therein, part of each of which rectangular slots is made by providing a radial slit in each of the discshaped portions, the apertures having a diameter which is slightly greater than the diameter of the cam discs of the selector and the rectangular slots having a width which is slightly larger than the diameter of the shank of the selector, the selectors being located in apertures formed in the object which is to be locked and unlocked, the apertures in the object having a diameter which is larger than that of the cam discs and less than that of the disc or head portions of the selectors, the bolt being coupled to the said selectors by means of a bayonet-type mounting by inserting the cam discs of the selectors into the apertures in the bolt, thereby causing the disc-shaped portions to be moved away by flexion of the corresponding connecting portions and then by axially displacing the bolt so as to locate the selector shanks in the rectangular slots, the disc-shaped portions then returning into a position in the same plane as the bolt and obstruct the apertures.

3. A lock as claimed in claim 1 wherein each selector incorporates a disc or head portion, a cylindrical pin or shank and at least one cam disc portion which are integral with one another each cam disc portion having a radially extending slot formed therein, the bolt being provided with as many apertures and rectangular slots as selectors each rectangular slot opening towards a respective one of the apertures and having an engaging projection or pin associated therewith, the apertures in the bolt forming passages for the insertion of the selector shanks or pins into the rectangular slots which have a width slightly greater than the diameter of the pin or shank of the selector but less than that of the cam discs the selectors being located in apertures formed in the object which is to be locked and having a diameter slightly greater than that of the cam discs but smaller than that of the disc or head portion, the bolt being connected by means of a bayonet connection to the selectors by the insertion of the selector legs or shanks into the apertures in the bolt.

4. A lock as claimed in any preceding claim in which a resilient portion of the bolt acts as a spring in the plane of the bolt.

5. A lock as claimed in any preceding claim in which a lug connected to the bolt is mounted and guided by means of a bayonet fitting on a support for the object to be locked or on the object itself.

6. A lock as claimed in claim 5 in which the lug is connected to a resilient portion of the bolt.

7. A lock as claimed in any preceding claim in which the radially extending slot formed in the at least one cam disc portion of each selector extends beyond the centre of the disc, the slot receiving a projecting having length corresponding to that of the slot so as to increase the possible travel of the bolt by the length of the slot.

8. A lock as claimed in any preceding claim in which the shank or pin of each selector has an axial bore formed therein which receives a rod which is rotatable and axially displaceable with respect to the shank or pin, one end of the rod being attached to a plate bearing reference indicia the other end of the rod being biassed by a spring, the spring urging the plate into a recess formed in the top surface of the disc or head portion so as to prevent the plate from rotating independently of the disc or head portion the rod being capable of axial displacement against the force of the spring to remove the plate from the recess and to allow the plate to be rotated with respect to the disc in order to change the combination which opens the lock.

9. A lock as claimed in claim 1 constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 6, Figs. 7 or Figs. 8 to 10 of the accompanying drawings.