TUMBLER LOCKS

Abstract: A cylinder lock comprising a body (1) having key barrels (2), (2a), rotatably journalled therein with cylinder pins (14), barrel pins (15), and springs (13) located in cylinders (10), the assembly of pins (14), (15) and springs (13) being releasably secured in the cylinders (10) by a removable cover member (16) having projections (20) locating in the outer ends of cylinders (10).

Description: TUMBLER LOCKS This invention is concerned with an improved method of manufacture of tumbler locks and improved tumbler ! * locks produced thereby. Key actuated tumbler locks (also known as 5 cylinder locks) are well known and generally comprise a plurality of spring biassed tumbler pins slidably located in a series of aligned parallel bores in a lock body. The pin bores are sealed at their outer ends to retain the biassing springs and at their inner ends, the bores open into a 10 cylindrical cavity. A rotatable key receiving cylindrical barrel is located within the cylindrical cavity. In the manufacture of such key actuated cylinder locks, the various component parts, and in particular the lock body, are traditionally constructed from brass both 15 for corrosion resistance and, importantly, ease of machining. The pin bores or cylinders are usually formed by drilling through the lock body adjacent the outer or normally sealed ends of the bore through to the interior of the barrel cavity. After the lock is assembled with the barrel 20 tumbler pins, springs etc., the outer ends of the cylinders are closed by press fitted pegs under considerable pressure to close the bores. Alternatively, the cylinders may be formed by drilling through the outer wall of the barrel cavity to form "blind" bores or cylinders in the lock body. 25 Although these methods of manufacture are generally satisfactory in constructing key actuatable cylinder lcoks, they nevertheless suffer a number of disadvantages. In view of the amount of machining involved, brass _* * 30 is traditionally chosen as an easily worked medium. Of r ^ recent years brass however has become a very expensive engineering material. The methodsof manufacture described above are very labour intensive in the many machining and assembly steps required. A further disadvantage is that in 35 the event of a lost key or damage to the lock, the services o a locksmith are required to individually drill out the cylinder closing pegs for access to the tumbler pins. After repair of the lock or manufacture of a suitable key, the closing pegs must be reinserted individually to close the cylinders. It is an aim of the present invention to overcome or alleviate the abovementioned disadvantages. According to one aspect of the invention there may be provided a cylinder lock including:- a lock body comprising a plurality of tumbler pin passages open at both ends and communicating at one end with the exterior of said lock body and at the other end with the interior of a key barrel aperture; and, a cover member adapted in use to close said tumbler pin passages adjacent the exterior of said lock body. Preferably said cover member includes projections which extend at least partially into said tumbler pin passages from an exterior end thereof. Preferably said cover member is adapted for releasable attachment to said lock body. Preferably said cover member is releasably secured ' to said lock body by a screw means extending through said cover member for screw threaded engagement in at least one tumbler passage. According to another aspect of the invention there may be provided a method of manufacturing a cylinder lock including the steps of:- forming a lock body with a plurality of tumbler pin passages open at both ends and communicating at one end with the exterior of said lock body and at the other end with the interior of a key barrel aperture; releasably securing a key barrel in said key barrel aperture for rotational movement therein; and, releasably retaining under the influence of biassing means a tumbler pin in one or more tumbler pin passages by releasably securing said cover member to said lock body to OMPI close said one end of said tumbler pin passages. Preferably the cover member is formed by a moulding operation, most preferably by die-casting. A preferred embodiment of the invention will now be described with reference to the accompanying drawings in whic FIG. 1 is a part cross-sectional side elevation; FIG. 2 is an end elevation. In FIG. 1, the lock comprises a double-sided lock which when fitted to a door or the like enables the door to be locked from either side via a centrally located lock actuating mechanism. The lock comprises a body 1 which may be formed from cast and/or machined brass or other suitable material but is preferably formed from die cast zinc. Rotatably joumalle in the body 1 are key barrels 2, 2a which are secured against withdrawal by circlips or the like 3 adjacent their inner ends and by abutment cf a shouldered rim 4 with a complementary shoulder 5 in the lock body. Between the opposed inner ends of barrels 2, 2a is a lock actuating member 6 with a projecting lug or cam 7 for engagement with a latch and/or deadlocking mechanism. Actuating member 6 may engage the ends of barrels 2, 2a by any suitable fixed or lost motion linkage. For example barrel 2a may include a projection 8 of polygonal cross section which engages a recess of complementary shape. Alternatively barrel 2 may include a pin 9 offset from the rotational axes of barrel 2 and actuating member 6. The pin 9 may engage a corresponding recess in member 6 for a fixed linkage or it may engage in an arcuate slot to provide a lost motion linkage if required. Body 1 is formed with a plurality of tumbler pin passages or cylinders 10 open at both ends and communicating between an exterior portion 11 of body 1 and the cylindrical aperture or chamber in which barrels 2, 2a rotate. Cylinders 10 also align with corresponding bores 12 in barrels 2, 2a. As in a conventional cylinder lock, the cylinders include springs 3 and cylinder pins or tumblers 14. 3arrel pins or tumblers 15 are located in bores 12 in the barrels 2, 2a. When key 16 is withdrawn from the barrel, barrel pins 15 followed by cylinder pins 14 drop to a predetermined position (usually approximately central) within the barrel. As can be seen from the illustration the two pairs of pins on either side of the central pin will fall to z_ e predetermined position. In such position, cylinder pins 15 will be located partly in cylinders 10 and parrly in bores 12 thus preventing rotation of barrels 2, 2a and actuating member 6. Upon insertion of an appropriate key 16 as illustrated the interface between cylinder pins 14 and barrel pins 15 is aligned with the outer surface of barrels 2, 2a whereby rotation of the barrels is permitted. After assembly cf the lock by insertion and interconnection of barrels 2, 2a via actuating member 6 and insertion of barrel pins 15, cylinder pins 14 and springs 13, a cover member 16 is placed over the upper part of lock body 1. The cover member 16 is releasably secured to the lock body via machine screw 17 or the like which is screw threadedly engaged in the upper portion of one of the cylinders 10. The head of screw 17 is preferably located in a recess 18 in cover 16 to permit a neat sliding fit in a door member, lock body or the like. Screw 17 is preferably located adjacent the central portion of the cylinder lock assembly such that the screw is inaccessible from outside the door member lock body or the like. A screw threaded aperture 19 is provided centrally of the lock assembly to secure it in a door, lock body or the like. The interior surface of cover 16 is preferably provided with projections 20 to locate within cylinders 10 to retain the spring and pins and, if required, to provide a degree of pre-loading of spring compression. FIG. 2 is an end elevation showing a cover 16 extending over the entire upper part of lock body 1. A slotted aperture 21 is provided in barrel 2 to receive a key. Although the present invention has been described with reference to a "double-sided" cylinder lock, it will be clear to a skilled addressee that the invention, with appropriate modification would be applicable to.a "single" lock. It will also be clear to a skilled addressee that locks according to the invention may be manufactured and assembled more easily than prior art locks of this type and in the event that maintenance is required, the lock may be readily disassembled and reassembled without the problems of prior art locks. Cylinder lock assemblies according to the invention may be manufactured by moulding, die casting, machining or any combination of these or analogous processes. In addition the lock assembly may be manufactured from suitable metals e.g. zinc, aluminium, brass, bronze, steel or the like as well as suitable plastics materials or any combination thereof. It will be apparent that many modifications or variations may be made to the invention without departing from the spirit and scope thereof.

Claims: CIAIMS : 1. A cylinder lock including:- a lock body comprising a plurality of tumbler pin passages open at both ends and communicating at one end with the exterior of said lock body and at the other end with the interior of a key barrel aperture; and, a cover member adapted in use to close said tumbler pin passages adjacent the exterior of said lock body. 2. A cylinder lock as claimed in claim 1 wherein said cover member includes projections which extend at least partially into said tumbler pin passages from an exterior end thereof. 3. A cylinder lock as claimed in claim 1 or claim 2 wherein said cover member is adapted for releasable attachment to said lock body. 4. A cylinder lock as claimed in any preceding claim wherein said cover member is releasably secured to said lock body by a screw means extending through said cover member for screw threaded engagement in at least one tumbler passage. 5. A method of manufacturing a cylinder lock including the steps of:- forming a lock body with a plurality of tumbler pin passages open at both ends and communicating at one end with the exterior of said lock body and at the other end with the interior of a key barrel aperture; releasably securing a key barrel in said key barrel aperture forrotational movement therein; and, releasably retaining under the influence of biassing means a tumbler pin in one or more tumbler pin passages by releasably securing said cover member to said lock body to close said one end of said tumbler pin passages. 6. A method according to claim 5 wherein said cover member is secured to said body by an attachment means adapted for releasable engagement in a tumbler pin passage. &?NAT\θ 7. A cylinder lock as claimed in any one of claims 1-4 wherein said lock body is adapted to receive two key barrels in opposed axial alignment, the adjacent ends of said key barrels engaging a latch operating member for rotation in an aperture in said lock body. 8. A cylinder lock substantially as hereinbefore described. 9. A cylinder lock substantially as hereinbefore described with reference to the accompanying drawings. 10. A method of manufacturing a cylinder lock substantially as hereinbefore described.

Inventors: SPREKELER OTTO GUNTHER, SPREKELER, OTTO, GUNTHER
Applicants: WHITCO PTY LTD, WHITCO PTY. LTD.
Application year: 1983
Main classification: E05B27
IPC codes: E05B27