PADLOCKS

Abstract: A padlock has a rotatable outer body part (24) which prevents the application of torque from a wrench to force the shackle (4) open. One or both ends of the padlock are also configured to prevent application of a wrench, the configuration being generally conical configuration (28) preferably at least at the shackle end (4) of the body of the padlock.

Description: PADLOCKS The present invention relates to padlocks. Conventional padlocks are relatively easy to force open. Usually, all that is necessary is to separately grip the body of the padlock and the bolt or shackle of the padlock and to force the shackle open from the body. Even hardened padlocks can be forced in this way by using a suitable wrench. According to the present invention there is provided a padlock comprising a body and a shackle mounted on the body for movement between a closed, locked, position and an open, released condition, wherein the body comprises an inner body part which mounts the shackle and an associated locking mechanism, and an outer body part mounted on the inner body part for rotation about the longitudinal axis of the body, said outer body part having a length sufficient to shield die inner body part against the application of a torque acting about the longitudinal axis of the inner body part to force the padlock, and the body having at least at one end portion a formation which progressively reduces in cross- sectional dimension whereby to impede the application of a wrench to the body such that the jaws of the wrench are applied to the opposite ends of the body. In a preferred embodiment, the said formation is a generally conical formation on the inner body part at the shackle end of the body. Alternatively or in addition the said conical formation may be at the end of the inner body part remote from the shackle end. Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:- Figure 1 is a perspective view of a padlock in accordance with the preferred embodiment of the invention; Figure 2 is a longitudinal section through the padlock to show schematically the operating components, a rotatable outer body part being omitted for the sake of clarity, Figure 3 is a longitudinal section showing the mounting of the outer body part on the inner body part; and Figures 4 to 6 are perspective views showing further embodiments of the invention. The padlock shown in Figures 1 to 3 of the accompanying drawings comprises a body 2 and a curved bolt or shackle 4. The body 2 consists of an inner body part 6 of a substantially cylindrical shape. The inner body part has diametrically-opposed longitudinally extending bores 8, 10 which receive opposed arms 12, 14 of the shackle 4. The arm 12 of the shackle is longer than the arm 14 and is displaceable in the bore 8 between an inner locked position in which the shorter arm 14 is within the bore 10, and an outer released position in which the end of the shorter arm 14 is fully withdrawn from the bore 10 to permit the shackle 4 to be applied to an article to be secured. The shackle 4 is held in its locked condition by locking means 16 which engage into recesses 18 on the inner surfaces of the arms 12, 14. The locking means 16 is releasable by actuation of a rotary lock mechanism 20 mounted within the inner body part 6. A key for releasing the lock mechanism 20 is inserted into the lock mechanism from the underside of the inner body part 6. In the open condition of the shackle 4, the locking means 16 engages within a further recess 22 formed at the lower end portion of the longer arm 12 to retain the shackle 4 against withdrawal from the body part 6 and to permit the shackle to swivel about the axis of the longer arm 12. The lock mechanism 20 and the locking means 16 can be of substantially conventional construction and will not be described in detail herein. An outer body part 24 is rotatably mounted on the inner body part 6 by bearings 26. The outer body part 24 is also of substantially cylindrical form and extends over the entire cylindrical outer surface of the inner body part 6. The cylindrical outer surface of the outer body part 24 and its rotatable mounting on the inner body part 6 prevents a wrench from being applied to the body to provide a reaction force acting about the longitudinal axis of the body in opposition to a force applied to the shackle 4 in an attempt to force open the shackle. We have also determined that for proper security it is necessary to configure the body so that a wrench cannot be applied to the body with the ends of the body held firmly between the jaws of the wrench. In the embodiment shown this is achieved by forming the shackle end portion of the body with a generally conical shape which provides a minimum of surface area on which a wrench jaw can grip. The conical end portion 28 is formed as an extension of the inner body part 6 and includes a recess for receiving the looped part of the shackle and a passage 30 which intersects that recess for receiving a component such as a chain link to be held by the shackle 4. In the embodiment shown, the conical end portion 28 is cut-away at 32 adjacent the bore 10 for the shorter arm 14 of the shackle 4. This cut-away portion 32 enables the shackle 4 to be swung open without the necessity of providing the shackle 4 with longitudinal movement sufficient to enable the end of the shorter arm 14 to clear the conical formation. Although this cut-away portion 32 does provide a surface 34 generally transverse to the longitudinal axis of the body, this surface is very small and is most unlikely to represent an area on which a sufficient grip could be obtained, especially as it is at the edge of the body. However, this surface 34 could, if necessary, be inclined at an acute angle to the longitudinal axis of the body, for example by being sloped downwardly towards the outer edge of the body in order to ensure that it is not parallel to a surface at the opposite end of the body. In an alternative configuration, the shackle 4 can be constructed to have sufficient longitudinal movement to permit the shorter arm 14 to be raised clear of the conical formation without the need for the cut-away portion. The rotatable outer body part 24 may have a shape other than cylindrical. For example as shown in Figure 4 the outer body part 24 is of convex form and in Figure 5 it is of concave form. In each case, the outer body part 24 is of annular section and is rotatably mounted on the inner body part. In the embodiment shown in Figure 6, the opposite end of the inner body part is also provided with a conical formation 36 which minimises at that end the transverse surface area on which the jaw of a wrench can grip. The embodiments have been described by way of example only and modifications are possible within the scope of the invention.

Claims: CLAIMS: 1. A padlock comprising a body and a shackle mounted on the body for movement between a closed, locked, position and an open, released condition, wherein the body comprises an inner body part which mounts the shackle and an associated locking mechanism, and an outer body part mounted on the inner body part for rotation about the longitudinal axis of the body, said outer body part having a length sufficient to shield the inner body part against the application of a torque acting about the longitudinal axis of the inner body part to force the padlock, and the body having at least at one end portion a formation which progressively reduces in cross-sectional dimension whereby to impede the application of a wrench to the body such that the jaws of the wrench are applied to the opposite ends of the body. 2. A padlock according to claim 1, wherein the said formation is a generally conical formation on the inner body part at the shackle end of the body. 3. A padlock according to claim 1 or claim 2, wherein the said formation is a generally conical formation at the end of the inner body part remote from the shackle end. 4. A padlock according to claim 3, wherein the conical formation is cut away at one side to permit the shackle to swing between an open and closed position. 5. A padlock according to any one of claims 1 to 3, wherein the outer body part is of annular section and surrounds the inner body part over a substantial portion of the length of the inner body part.

Inventors: LONG RUSSELL PHILLIP, LONG, RUSSELL, PHILLIP
Applicants: LONG RUSSELL PHILLIP, R P L IND PTY LTD, R.P.L. INDUSTRIES PTY. LTD.
Application year: 1993
Main classification: E05B67
IPC codes: E05B17, E05B67