IMPROVEMENTS TO A LOCKING DEVICE

Abstract: A locking device comprising a cylinder body (4) having two locking cylinders (8, 9) therein, said cylinder body (4) including a bight (5) intermediate its ends to accommodate a locking cam (10), being driven by said locking cylinders (8, 9), said device characterized in that said locking cylinders (8, 9) drive said locking cam (10) via respective drive rings (20, 21) adapted to engage said locking cam. A locking device comprising a cylinder body (4) having two locking cylinders (8, 9) therein, said cylinder body (4) including a bight (5) intermediate its ends to accommodate a locking cam (10) being driven by said locking cylinders (8, 9), said device characterized by said locking cylinders (8, 9) being structurally connected whilst allowing rotation of one locking cylinder relative to the other.

Description: 1 PROVEMENTSTO A LOCKING DEVICE This invention relates to locks, particularly locks known as European style mortice lock cylinders. The European lock cylinders of the prior art had two locking cylinders at opposite ends of a cylinder body thus allowing key access from two sides of a closure such as a door. However, they included a clutch arrangement between the lock cylinders which enabled a door-latch mechanism to be activated by the insertion of a key into the lock. This activated the clutch by the tip of the key pushing the clutch forward to engage a locking cam. This led to the problem that once a key was placed inside the door-lock, it was impossible to insert another key from the other side in order to either lock or unlock the latch. A further difficulty with these prior art locks was that the cylinder body usually included a bight intermediate its ends. The arrangement of the clutch and locking cylinders however, was such that there was no structural interaction between the locking cylinders. This meant that the mechanical strength of the lock was reliant upon the bridge which joined the two parts of the cylinder body together. Unfortunately, because of this weakness when one end of the cylinder lock body was broken, unauthorised forcing of the lock was comparatively easy. It is an object of the present invention to provide a locking device which substantially overcomes or ameliorates the disadvantages of the prior art. According to one aspect of the present invention there is disclosed a locking device comprising a cylinder body having two locking cylinders therein, said cylinder body including a bight intermediate its ends to accommodate a locking cam, said locking cam being driven by said locking cylinders, said device characterised in that said locking cylinders drive said locking cam via respective drive ring adapted to engage said locking cam and allow rotation of one locking cylinder whether or not a key is placed in the other locking cylinder. According to a further aspect of the present invention there is disclosed a locking device comprising a cylinder body having two locking cylinders therein, said cylinder body including a bight intermediate in its ends to accommodate a locking cam being driven by said locking cylinders, said device characterised by said cylinders being structurally connected whilst allowing rotation of one locking cylinder relative to the other. Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 illustrates an exploded perspective view of a locking device embodying the present invention, and Figure 2 illustrates an exploded perspective view of a preferred form of the present invention. Illustrates in Figure 1 , the locking device of the present invention comprises a cylinder body 1, having first and second portions 2 and 3, joined by a bridge 4, which forms a bight 5 between portions 2 and 3. Through portions 2 and 3 are holes 6 and 7, allowing the cylinder body 1 to house two lock cylinders 8 and 9. The lock cylinders 8 and 9 operate a latch (not illustrated) by means of a locking cam 10. Locking cam 10 is located in bight 5 on cylinder body 1, once all parts are assembled. The lock cylinders 8 and 9 engage locking cam 10 by means of drive rings 11 and 12. Drive rings 11 and 12 have a substantially cylindrical construction, and include engaging portions to positively engage locking cam 10. The driver rings 11 and 12 will not engage locking cam 10 unless a key is placed inside either of locking cylinders 8 or 9. The locking cylinders 8 and 9, drive rings 11 and 12, locking cam 10 and spring 13 circlip 14 and connector 15 are assembled in the body in the following manner. The internal end 16 of locking cylinder 9 has a female thread to receive male thread 17 on connector bar 15. Drive ring 12 is located and arranged so that it is adjacent locking cylinder 9. The locking cam 10 is then placed inside bight 5 and the now partly assembled locking cylinder 9 placed in hole 7 on cylinder body 1. Circlip 14 is located on the lock cylinder 8 at an end 18 and driver ring 11 placed adjacent this end thereof. Partly assembled locking cylinder 8 is then inserted in hole 6 of cylinder body 1 and the free end of connector bar 15 engages circlip 14 thereby structurally connecting together locking cylinders 8 and 9 and thus preventing them from being pulled apart. In operation, a key can be placed in either of the locking cylinders say for example, locking cylinder 8, and this key pushes driver ring 11 against the bias of spring 13 into locking cam 10. Mating protrusions engage on driver ring 11 and locking cam 10 and by rotating the key locking cam 10 will move a latch (not illustrated). If the key is left in locking cylinder 8 because drive ring 11 has not protruded fully into locking cam 10 another key can be inserted in locking cylinder 9 pushing driver ring 12 against the bias of spring 13 into locking cam 10. By this operation, a latch (not illustrated) can be activated or de-activated by a key in one locking cylinder even though another key is in place in the other locking cylinder. Generally, by means of circlip connection 14 between connector 15 and locking cylinder 8 each of the locking cylinders 8 or 9 can rotate independently of the other, unless there exists a key in for example lock cylinder 8 and the lock is operated by a key in lock cylinder 9. 5 By the interconnection between the lock cylinders 8 and 9 a stronger cylinder body is obtained in that this structural connection between the locking cylinders 8 and 9 provides reinforcement to the bridge 4 on cylinder body 1. In effect, a rigid supporting rod is formed comprising lock cylinders 8 and 9, and connector bar 15. This gives the cylinder body 1 with more strength as the mechanical strength of the cylinder body is no 1 0 longer relied only on the bridge 4 as it would be in prior art systems. A most preferred embodiment is illustrated in Figure 2. Its manner of operation is similar to the embodiment of Figure 1 , except for the differences described below. Like parts have been identified with the same numerals as Figure 1. Assembly of this embodiment into the cylinder body 1 is as follows. Drive 1 5 dogs (also called drive rings) 20 and 21 , spring 13 and locking cam 10 are located on connecting bar 22, with spring 13, acting to space and bias drive dogs 20 and 21. Once concentrically located drive dogs 20, 21, spring 13 and locking cam 10 are held onto connecting bar 22 by means of a screw 23, which is rewired into threaded portion 24 of cylinder 9. Whilst connecting bar 22 is internally threaded at 25, the 20 screw 23 does not engage this female thread 25. Male thread 26 on cylinder 8 engages female thread 25, thus structurally completing the connection between cylinders 8 and 9. The cylinders 8 and 9 have locating protrusions 27 on each side which engage channel portions 28 in the cylinder body 1. Further a threaded securing hole 29 is 25 provided in cylinder body 1 to prevent movement of the lock when it situ. In operation, a key placed in cylinder 8 will slide connecting bar 22 and drive dog 21 in the direction of locking cam 10. Keyway 30, on drive dog 21 , engages a protrusion on connecting bar 22 to allow for positive rotation of the drive dog 21 when the key is inserted into cylinder 8. The flat surface 31 engages a corresponding surface 30 32 internally located on locking cam 10. These surfaces 31 and 32 engage when a key is placed in cylinder 8. In this manner, a positive rotation of locking cam 10 is achieved. Insertion of a key into cylinder 9 achieves a similar effect, except that connecting bar 22 is not present. The foregoing describes illustrative embodiments of the present invention and modifications by those skilled in the art can be made thereto without departing from the scope of the present invention.

Claims: £_______: 1 . A locking device comprising a cylinder body having two locking cylinders therein, said cylinder body including a bight intermediate its ends to accommodate a locking cam, said locking cam being driven by said locking cylinders, said device characterised in that said locking cylinders drive said locking cam via respective drive rings adapted to engage said locking cam. 2. A locking device comprising a cylinder body having two locking cylinders therein, said cylinder body including a bight intermediate its ends to accommodate a locking cam being driven by said locking cylinders, said device characterised by said locking cylinders being structurally connected whilst allowing rotation of one locking cylinder relative to the other. 3. A locking device as claimed in claim 1 wherein said lock is further characterised by said locking cylinders being structurally connected whilst allowing rotation of one locking cylinder relative to the other. 4. A locking device as claimed in claim 2 wherein said device is further characterised in that said locking cylinders drive said locking cam via respective drive rings adapted to engage said locking cam. 5. A locking device as claimed in any one of claims 1 , 3 or 4 wherein said drive rings are substantially circular with at least one flat surface. 6. A locking device as claimed in any one of claims 2 to 5, wherein the locking cylinders are structurally connected by at least one threaded member. 7. A locking device as claimed in claim 6 wherein one of said locking cylinders is a male member and has an external thread on a portion thereof and the other locking cylinder is a female member having an internal thread portion. 8. A locking devices as claimed in claim 7 wherein a connecting bar having a bore therethrough, receives a bolt or screw which engages said female member, said bore being internally threaded to engage said male member. 9. A locking device as claimed in claim 8 wherein one of said drive rings is mounted on said connecting bar, and the other is mounted on said female member.

Inventors: PREDDEY BRIAN, PREDDEY, BRIAN
Applicants: AUSTRALIAN LOCK CO, AUSTRALIAN LOCK COMPANY PTY. LTD.
Application year: 1991
Main classification: E05B17
IPC codes: E05B9