GB2071198A - Padlock - Google Patents

Abstract

A padlock shackle 5 has two legs 5a, 5b of different lengths provided with locking notches 7a, 7b, respectively. The padlock has a positively guided tumbler disc cylinder lock mechanism 4 operable by a key which can only be removed from the lock mechanism when the latter is in its locking position. Locking bolts 9, operated by the lock mechanism 4, lock both legs of the shackle 5. A cover element 2, which is slidable in the casing 1 in the plane of the shackle 5, covers the lock mechanism 4. The longer shackle leg 5a is provided with a second notch 12 dimensioned and positioned for receiving the locking bolt 9. In the withdrawn position of the shackle 5, the key of the padlock can be removed. This allows the cover element 2 to be slid off the lock casing 1, which in turn allows removal of the lock mechanism 4. <IMAGE>

Description

SPECIFICATION Padlock This invention relates to a padlock of the kind comprising a lock casing and a basically U-shaped shackle slidable therein and having two legs of different lengths and each provided with a locking notch, a positively guided tumbler disc cylinder lock mechanism, operable by a key which is removable therefrom only when the lock mechanism is in its locking position, locking bolt members positively guided by said cylinder lock mechanism into engagement with said locking notches for locking both legs of said shackle to said lock casing, and a cover element slidable in the lock casing for covering tle cylinder lock mechanism.

Padlocks are known in which elements of the lock mechanism can be replaced, so that it is possible to change the opening combination of the padlock without destroying the padlock. In these known padlocks, however, the relocking of the mechanism is merely spring-actuated. The strength of padlocks of this kind, usually having tumbler pins or the like, is not so great as that of padlocks of the same size but having an all over positively guided lock mechanism. Furthermore, in contrast to a padiock with a spring-actuated lock mechanism, a padlock with a positively guided lock mechanism is practically pick-proof.However, for avoiding misuse of the padlock it is of importance that the lock mechanism members of positively guided padlocks, which per se are reliable and of first class strength, should be replaceable for changing the opening combination of the padlock, so avoiding the need to have a completely new padlock.

The present invention aims to provide a positively guided padlock of a new construction, which makes it possible to replace the lock mechanism members of the padlock without destroying the padlock.

According to the invention, a padlock of the kind referred to, is characterised in that the cover element is slidable in the plane occupied by the shackle when both legs of the latter are locked to said lock casing, and in that the longer shackle leg comprises a second notch dimensioned and positioned for receiving the locking bolt member of the longer shackle leg to an extent allowing rotation of said lock mechanism by its key, when said shackle is in a position in which its shorter leg is completely outside said lock casing, thereby allowing said cylinder lock mechanism to be set in locked position when said shorter shackle leg is free from said lock casing.

In order to prevent picking of a padlock in accordance with the invention, directed, in particular, to the slidable cover element, the latter is preferably attached to the lock casing by means of a fastening member, for example a screw, which is located in the lock casing at the bottom of the boring for the shorter shackle leg.

Furthermore, the longer shackle leg may be so dimensioned that, in the fully locking position of the padlock, it is partly received in a recess in the cover element. In this way, the slidably mounted cover element is locked by two elements, so that its sliding movement is prevented. This will make the padlock highly resistant to picking.

The invention will now be described, by way of example, with reference to the accompanying drawing, in which Figure 1 is a sectional side view of one embodiment of a padlock in accordance with the invention, in locked position, Figure 2 is a sectional view taken on the line Il-Il of Figure 1, and Figure 3 is a sectional side view similar to Figure 1 but showing the padlock in a condition in which its cover element is removable.

The padlock shown in the drawing has a lock casing 1 which is provided with a laterally slidable cover element 2 which has oblique guide surfaces 14 engaging in a dovetail groove 1 6 in the casing 1, as can be seen in Figure 2. The cover element 2 is secured to the casing 1 by means of a screw 3 which is accessible through a boring 6 in the casing 1. The cover 2 protects a cylinder lock mechanism 4 in the lock casing. The padlock comprises a U-shaped lock shackle 5 having a long leg 5a and a shorter leg 5b, which legs are provided with notches 7a and 7b, respectively, for receiving spherical bolt members 9.

The bolt members 9 are positively guided by means of guide portions 10 at one end of the cylinder of the lock mechanism 4, so that they move radially outwards relative to the mechanism 4, into the notches 7a and 7b of the shackle 5, when the cylinder lock mechanism is turned to the locked position of the padlock. In this way the shackle 5 will be firmly locked to the casing 1 at two positions. When the padlock is to be opened, the cylinder lock mechanism is first turned by a key (not shown) into its open position, to bring recesses 15, located at the same end of the cylinder of the lock mechanism 4 as the guide portions 10, to face the bolt members 9.The shackle 5 can then be withdrawn from the lock casing 1 to the extent that the shorter shackle leg Sb completely leaves its boring 6, which position of the shackle is referred to hereinafter as its retracted position.

The cylinder lock combination may be changed in the following way: The padlock is opened by bringing the shackle to its retracted position, and the shorter leg Sb of the shackle 5 is moved to one side of the boring 6 by turning the shackle in the boring of its longer leg 5a. The fastening screw 3 of the cover element 2 can now be unscrewed. Due to the dovetailing of the cover element 2 in the casing 1 , the cover element 2 can only move perpendicularly to the axis of the lock cylinder. Thus, the key has to be removed from the padlock before the cover element 2 can be removed from the groove 16.

However, as a result of the positively guided action of the lock mechanism 4, removal of the key can only take place when the lock mechanism is in its locking position, in which the bolt members 9 are forced radially outwards relative to the lock cylinder. In order to make this movement possible when the shackle 5 is in its retracted position, there is a slot 12 in the longer shackle leg 5a which receives one of the bolt members 9 when the shackle leg 5a is turned in its boring in the casing 1 through approximately 900 from the position shown in Figure 1 to the position shown in Figure 3. When the key has been removed from the padlock, the cover element 2 can be removed.

The cylinder lock mechanism 4 can then be removed from the lock casing 1 and its opening combination can be changed. For re-assembling the padlock, the described steps are taken in the reverse order.

The exact axial position of the slot 12 in the longer shackle leg 5a can be freely chosen, provided that the shorter shackle leg Sb is completely withdrawn from the boring 6 when the slot 12 is brought up to the locking bolt member 9 associated with the shackle leg 5a. The end portion of the longer shackle leg 5a is wide enough to prevent, in cooperation with its bolt member 9, complete removal of the shackle 5 from the lock casing.

For increasing the security of attachment of the cover element 2, it is provided with a recess 8 which receives the end portion of the longer shackle leg 5a when the padlock is locked. Thus, the oblique guide surfaces 14 prevent removal of the cover element 2 from the lock casing in the axial direction of the lock cylinder and the screw 3 and the longer shackle leg 5a prevent movement of the cover element 2 perpendicularly to the axis of the lock cylinder.

Claims (4)

1. A padlock comprising a lock casing and a basically U-shaped shackle slidable therein and having two legs of different lengths and each provided with a locking notch, a positively guided tumbler disc cylinder lock mechanism, operable by a key which is removable therefrom only when the lock mechanism is in its locking position, locking bolt members positively guided by said cylinder lock mechanism into engagement with said locking notches for locking both legs of said shackle to said lock casing, and a cover element slidable in the lock casing for covering the cylinder lock mechanism, characterised in that the cover element is slidable in the plane occupied by said shackle when both legs of the latter are locked to said lock casing, and in that the longer shackle leg comprises a second notch dimensioned arid positioned for receiving the locking bolt member of the longer shackle leg to an extent allowing rotation of said lock mechanism by its key, when said shackle is in a position in which its shorter leg is completely outside said lock casing, thereby allowing said cylinder lock mechanism to be set in locked position when said shorter shackle leg is free from said lock casing.

2. A padlock according to claim 1, in which, for fastening and locking the cover element in said lock casing, there is a fastening member at the bottom of the boring for the shorter shackle leg.

3. A padlock according to claim 2, in which the longer shackle leg is so dimensioned that, in the fully locking position of the padlock, it is partly received in a recess in the cover element.

4. A padlock constructed and arranged substantially as herein described with reference to, and as illustrated in, the accompanying drawing.