GB2256227A - Combination lock - Google Patents

Abstract

A combination lock which can be freely coded, in which locking discs are rotatably mounted and arranged one behind the other on a common spindle (15) connected to an adjusting knob (16). A sleeve (27) of a bolt operator (4) is arranged between a lock housing (1) and locking disc rims (8) and locking balls (10) engage either in groove (25) of the lock housing (1) to lock the sleeve or recesses (24) of the rims (8). The knob (16) is turned and pulled to align recesses (24) of the locking disc rims (8) with the balls (10). Preferably, the wall thickness of the sleeve (27) of the bolt operator (4), the depth of the groove (25) in the lock housing (1) and the depth of the recess (24) in the rim (8) are such that they each correspond to half the diameter of the locking ball (10). <IMAGE>

Description

COMIBINATION LOCK This invention relates to a combination lock having actuating means for a combination of numbers and a turning handle for actuation of a bolt. The combination lock is also provided with locking means for the bolt and adjusting means for the free coding of the combination of numbers.

Combination locks of different designs are known. Some designs have locking discs which are adjusted by associated adjusting knobs (usually three) actuated from the outside, while a fourth knob serves for actuation of the bolt.

In other designs, part of the circumference of the locking discs provided with the numbers projects from the housing. Each locking disc is actuated and rotated directly by hand when setting the opening code. If the user forgets to rotate the locking discs after opening the lock, the opening code can then also be detected and used by unauthorised persons.

Other combination locks require a separate lock case for the arrangement of the locking discs, fitted to the rear of the door or the like, said lock case having very large dimensions and partially obscuring the view of the object in the case of open doors, and being unsuitable for certain applications as a result of the size of the lock case. Moreover, in the case of an unlocked lock, when opening from the rear, the code can be adjusted simply and rapidly by unauthorised persons.

In another combination lock having only one actuating knob, in addition to the aforementioned disadvantages of the special lock case on the rear of the lock, a special bar is required outside the lock. In other combination locks having an actuating knob, the latter has to be rotated out of its basic position several times in opposite directions according to the number of locking discs.

According to one aspect of the invention, there is provided a combination lock which can be freely coded comprising a plurality of locking discs which are rotatably mounted and arranged one behind the other on a common spindle, an adjusting knob connected thereto, a sleeve on a turning bolt arranged between a lock housing and the rim of said locking disc and a locking ball which cooperates selectively with a groove in the lock housing or a recess in said rim.

Preferably, the wall thickness of the sleeve of the turning bolt, the depth of the groove in the lock housing and the depth of the recess in the rim are such that they each correspond to half the diameter of the locking ball.

In a preferred embodiment, the sleeve of the turning bolt is arranged between the lock housing and the rim and the locking ball corresponds selectively with the groove of the lock housing or the recess of the rim, the wall thickness of the sleeve of the turning bolt, the depth of the groove in the lock housing and the depth of the recess in the rim being such that they each correspond to half the diameter of the locking ball.

The preferred lock of the present invention has the following advantages: a) it requires little space and takes account of the installation dimensions of former cylinder locks, so that it is possible to convert cylinder locks into combination locks; b) it prevents the combination (code) from being read in the case of locking discs situated in the unlocked position (opening code); c) it makes it extremely difficult for unauthorised persons to adjust the code in the open state; d) when opening the lock, it allows the actuating knob to be rotated from its basic position equally to the left or the right as desired and is not restricted to a predescribed sequence; e) the combination of numbers set is not shifted automatically during or after opening.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section of a combination lock of the invention in its closed condition; Figure 2 is a section along the line A-A of Figure 1; Figure 3 is a longitudinal section of a combination lock of the invention in its open condition; Figure 4 is a section of Figure 3; Figure 5 is a longitudinal section of the combination lock with the locking sleeve released, and; Figure 6 is a section along the line B-B of Figure 1.

Referring to the drawings, there is shown a lock housing 1 for insertion into the receiving bore in a door or drawer or the like which can be rigidly connected to the door or the like by means of screw nut 3 and retaining washer 2. Turning bolt 4 having an integral sleeve 27 is mounted in the lock housing 1.

When the opening code is set, the turning bolt 4 must be rotated through a specific angle, preferably 90 degrees, with respect to the lock housing 1.

The angle of rotation is limited by stops 14. A bolt 5 secured to the turning bolt 4 by a screw 6 is moved by the rotational movement and can thus fulfil the function of locking or unlocking. By virtue of the fact that the bolt 5 is screwed on to the turning bolt 4, the latter is axially mounted in the lock housing 1.

The turning bolt 4 serves to receive a latch 7 and ratchet wheels having a rim 8 and locking sleeve 9, locking balls 10, spacer sleeve 11 and bearing bush 12.

The bearing bush 12 is arranged centrally on the turning bolt 4 and is secured against displacement and rotation in the axial direction by means of grooved pins 13.

The axial position of the rims 8 and the bearing bush 12 is ensured by the interposed spacer sleeve 11.

A spindle 15 is guided through the bearing bush 12 and the latch 7.

An adjusting knob 16 is connected in a torsionally rigid manner to the spindle 15. Code figures (not shown) are applied to surface 17 on the circumference of the adjusting knob 16. The number of the figures 17 must correspond to the notches 18 on the rim 8 of the ratchet wheel.

If the adjusting knob 16 is displaced in the radial direction, the locking sleeve 9 and the rim 8 are also radially displaced via the spindle 15 having adjusting spring 19 and associated annular groove 22.

Spring tongues 20 arranged in a window on the turning bolt 4 engage with notches 18 in the rim 8 of the ratchet wheel and thus ensure definite locking when the code is adjusted or set.

The spindle 15 locks into different bearing arrangements in the axial direction according to the number of ratchet wheels. Locking is achieved by the cooperation of locking balls 21 being subjected to spring pressure in the bearing bush 12 in the annular grooves 22 of the spindle 15.

Longitudinal movement of the spindle 15 is limited by collar 23 and the bearing bush 12. The rim 8 of the ratchet wheel has on its circumference, on the laterally mounted notches 18, a recess 24 for receiving locking ball 10 when the opening code is set.

The dimensions of the recess 24 are such that it has the depth of half the diamter of the ball 10, the segment width being a function of the number of figures selected and the diameter of the rim 8.

If the selected combination is to be set in order to open the lock, the figures selected for the code must be set via the adjusting knob 16, beginning from the inside to the outside, from the first on to the last locking disc.

The locking balls 10 then fall by half the ball diameter out of the groove 25 in the lock housing 1 into the recess 24 in the ratchet wheel, release the previously existing connection between the turning bolt 4 and the lock housing 1 and thus form the connection between the locking sleeve 9 and the turning bolt 4.

The desired opening or closing movement of the bolt 5 can be achieved in this manner via the turning bolt 4.

The combination can only be changed when the lock is open. To this end, the turning bolt 4 is removed from the lock housing 1 together with the entire internal structure after unscrewing the bolt 5. The rims 8 are released from the ratchet wheels in this manner. When the latch 7 is actuated, the coupling between the rim 8 and the locking sleeve 9 is released and the rim 8 can then be displaced with respect to the adjusting knob 16. To this end, the adjusting knob 16 must advantageously first be rotated to the code figure "0" (not shown). When actuatin of the latch 7 ceases, a compression spring 26 reestablishes the coupling between the rim 8 and the locking sleeve 9 and the new code is set.

Claims (3)

1. A combination lock which can be freely coded comprising a plurality of locking discs which are rotatably mounted and arranged one behind the other on a common spindle, an adjusting knob connected thereto, a sleeve on a turning bolt arranged between a lock housing and the rim of said locking discs and a locking ball which cooperates selectively with a groove in the lock housing or a recess in said rim.

2. A lock according to claim 1 wherein the wall thickness of the sleeve of the turning bolt, the depth of the groove in the lock housing and the depth of the recess in the rim are such that they each correspond to half the diameter of the locking ball.

3. A combination lock substantially as herein described with reference to the accompanying drawings