GB1567783A - Lock - Google Patents

Description

(54) A LOCK (711) 1, SIK ON TAM, of 198 Nathan Road, 4th Floor, Kowloon, Hong Kong, of Chinese Nationality, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement : - The present invention relates to locks.

According to the present invention there is provided a lock having at least three discs coupled together for common rotational movement within a hollow body each disc having a centrally located opening and said discs being different in that a first one comprises a pair of tumblers, a second one comprises a pair of fixed wards and a third one comprises a tumbler and a fixed ward, the arrangement being such that when the discs are coupled together in predetermined sequence in withe hollow body, the openings are aligned to provide a keyway and the tumblers engage the hollow body to prevent rotation of the coupled discs relative thereto, said tumblers being retractable into their respective discs upon actuation by a required combination of actuating members of a key inserted in the keyway to thereby permit rotation of the coupled discs relative to the hollow body, said wards p.reventing actuation and retraction of the said tumblers by a key inserted in the keyway and not having said required combination of actuating members.

The invention will now be further described by way of example with reference to the accompanying drawing wherein: Figure 1 shows a single disc segment; Figure la shows a normally projecting lock member; Figure ib shows a ward; Figures 2a to 2d are cross-sectional views of four possible combinations of disc segments and lock members; Figures 3a and 3b are respectively plan and elevational views of an end disc segment of a lock; Figure 4 illustrates the four discs of Figure 2 assembled in a lock which is shown in longitudinal section; Figure 5 is a sectional view through the lock body; Figure 6 shows an end disc in front elevation; and Figure 7 shows a key.

The single disc shown in figure 1 is a moulded disc. The parts shown shaded indicate recesses cut through about three quarters of the thickness of the disc. In the centre of the disc is a through hole 1 into which the key will be inserted. Around this central hole are two part circular sectors 2 in which the bittings of a key can move.

On either side of this central portion, are two tracks 3 in which tumblers can be posiltioned. At the bottom of each track 3 are two ledges 4. The purpose of these ledges will be described later. On the periphery of the discs are two further recesses 5. On the opposite face of the disc, there are corresponding projections (not shown). When a number of discs are assembled together, the projections on one disc engage in the recesses on the adjacent disc, so that all the discs will rotate as one.

Figure la shows a tumbler 6 having a long shaft 7 which slides in a track 3, and a lug 8 which will be contacted by a bitting on the key. The ward 9 shown in Figure ib also has a lug 8 of the same shape as the lug on the tumbler.

In Figure 2, four discs are shown with tumblers inserted in the tracks 3. When a tumbler 6 is in place, a compression spring 10 is placed below it and between the ledges 4 to bias the tumbler into a position where it extends beyond the circumference of the disc. When a ward 9 is inp lace, it rests on the ledges 4, which prevent any movement of the ward should its lug 8 be contacted by a bitting of a key. If a bitting should therefore be positioned such that it contacts the ward, it will be impossible to turn the key fully. When the four discs shown in Figures 2 are assembled together with their circumferential projections engaging in the recesses 5, it will be seen that a lock body is formed with a central through hole for a key, which must have a characteristic position of bittings if it is to operate the lock, i.e. depress all of the normally projecting tumblers 6 simultaneously.

To complete the assembly of discs, a front plate 1.1 and a rear plate 12 are provided.

The front plate 11 has a pair of circumferential projections l,la to engage in the recesses 5 of the adjacent disc. The rear plate 1R has a corresponding pair of recesses 5, which are not shown. The rear plate 12 also has a bar 13 for operating a locking member when the assembly of discs is turned.

The assembly of segments is inserted inside a lock body 14 shown in Figures 4 and 5. This lock body has two opposite annular grooves 15 in which the projecting ends of the tumblers 6 will be received. To turn the assembly of discs relative to the lock body, it is obviously necessary to retract simultaneously all the tumblers 6.

A suitable key is shown in figure 7. The key has bittings arranged specifically to Co- operate with the series of discs shown in figures 2.

Each bitting 16 of thekey will engage the tip of a lug 8 on the tumblers 6 when the key is turned in the keyway formed by the through holes. In this way, each tumbler 6 is withdrawn into its respective disc. If the wrong key is inserted, with too few bittings, then not all of the tumblers 6 will be properly retracted. If the inserted key has too many bittings, one of these will come into contact with one of the wards, and it will therefore be impossible to turn the key to retract the tumblers.

WHAT I CLAIM IS:- 1. A lock having at least three discs coupled together for common rotational movement within a hollow body each having a centrally located opening and said discs being different in that a first one comprises a pair of tumblers, a second one comprises a pair of fixed wards and a third one comprises a tumbler and a fixed ward, the arrangement being such that when the discs are coupled together in predetermined sequence in the hollow body, the openings are aligned to provide a keyway and the tumblers engage the hollow body to prevent rotation of the coupled discs relative thereto, said tumblers being retractable into their respective discs upon actuation by a required combination of actuating members of a key inserted in the keyway to thereby permit rotation of the coupled discs relative to the hollow body, said wards preventing actuation and retraction of the said tumblers by a key inserted in the keyway and not having said required combination of actuating members.

2. A lock substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. i.e. depress all of the normally projecting tumblers 6 simultaneously. To complete the assembly of discs, a front plate 1.1 and a rear plate 12 are provided. The front plate 11 has a pair of circumferential projections l,la to engage in the recesses 5 of the adjacent disc. The rear plate 1R has a corresponding pair of recesses 5, which are not shown. The rear plate 12 also has a bar 13 for operating a locking member when the assembly of discs is turned. The assembly of segments is inserted inside a lock body 14 shown in Figures 4 and 5. This lock body has two opposite annular grooves 15 in which the projecting ends of the tumblers 6 will be received. To turn the assembly of discs relative to the lock body, it is obviously necessary to retract simultaneously all the tumblers 6. A suitable key is shown in figure 7. The key has bittings arranged specifically to Co- operate with the series of discs shown in figures 2. Each bitting 16 of thekey will engage the tip of a lug 8 on the tumblers 6 when the key is turned in the keyway formed by the through holes. In this way, each tumbler 6 is withdrawn into its respective disc. If the wrong key is inserted, with too few bittings, then not all of the tumblers 6 will be properly retracted. If the inserted key has too many bittings, one of these will come into contact with one of the wards, and it will therefore be impossible to turn the key to retract the tumblers. WHAT I CLAIM IS:-

1. A lock having at least three discs coupled together for common rotational movement within a hollow body each having a centrally located opening and said discs being different in that a first one comprises a pair of tumblers, a second one comprises a pair of fixed wards and a third one comprises a tumbler and a fixed ward, the arrangement being such that when the discs are coupled together in predetermined sequence in the hollow body, the openings are aligned to provide a keyway and the tumblers engage the hollow body to prevent rotation of the coupled discs relative thereto, said tumblers being retractable into their respective discs upon actuation by a required combination of actuating members of a key inserted in the keyway to thereby permit rotation of the coupled discs relative to the hollow body, said wards preventing actuation and retraction of the said tumblers by a key inserted in the keyway and not having said required combination of actuating members.

2. A lock substantially as hereinbefore described with reference to the accompanying drawings.