Safety Lock

Abstract

An improved safety lock which includes two pivotally connected members each having a shank portion with an aperture therein and a hook portion. The shank portions of the pivoted members are adapted to overlap with the apertures therein being placed in registry so as to receive the hasp of a padlock. With the shank portions of the members overlapping and the holes therein placed in registry, the free end parts of the hook portions overlap to define, in association with the remainder of the hook portions, a continuous lock ring which is adapted to extend through an anchoring aperture and around a lever or handle of a switch or valve in order to prevent the actuation of the switch or valve. The overlapping end parts of the lock's hook portions include components which cause the end parts to interlock so as to prevent the hook portions from being separated and disengaged from the switch or valve without the release of the padlock which extends through the shank portions of the safety lock and which normally prevents separating movement of the hook portions.

Description

SUMMARY OF THE INVENTION

This invention relates to a safety lock for preventing actuation of a valve, switch or similar control device and for preventing access to control elements within a container such as a switch or fuse box.

Safety locks, as illustrated in U. S. Pat. No. 2,560,624 and granted in 1951, provide a margin of safety for maintenance personnel, machine operators and electricians, and have been known and used for many years. Prior art devices of this nature generally comprise two pivotal members having overlapping hook portions which are used to engage the actuating member of a valve, switch or similar control device to prevent actuation of the control device until the safety lock is removed. Such removal of the safety lock is intended to be prevented until the last of one or more padlocks which prevent pivotal movement of the hook portions are removed from the lock so as to allow the hook portions thereof to be separated and disengaged from the actuating lever of the control device. In actual practice, however, it has been possible to forceably separate the hook portions of the safety lock so as to free the actuating lever of the control device without having to remove all of the padlocks from the lock. In this invention, the hook portions of the safety lock include interlocking parts which prevent forceable separation of the hook portions until the last padlock is removed from the lock.

Accordingly, it is an object of this invention to provide a safety lock for preventing actuation of a control device, such as switches and valves, in which means is provided for preventing the forceful removal of the lock from the control device until the lock can be safely removed by authorized personnel.

Another object of this invention is to provide a safety lock for preventing actuation of a control device which is of economical construction and of high reliability.

Other objects of this invention will become apparent upon a reading of the invention's description.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of one embodiment of the safety lock of this invention shown with the hook portions thereof closed.

FIG. 2 is a perspective view of the safety lock of FIG. 1 shown with the hook portions thereof opened.

FIG. 3 is a side view of the safety lock of FIG. 1.

FIG. 4 is a sectional view taken along line 4--4 of FIG. 3.

FIG. 5 is a fragmentary side view of the closed hook portions of the safety lock of FIG. 1 shown in modified form.

FIG. 6 is a sectional view taken along line 6--6 of FIG. 5.

FIG. 7 is a fragmentary side view of the closed hook portions of the safety lock of FIG. 1 shown in another modified form.

FIG. 8 is a fragmentary view as seen from line 8--8 of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments illustrated are not intended to be exhaustive or to limit the invention to the precise forms disclosed. They are chosen and described in order to best explain the principles of the invention and its application and practical use to thereby enable others skilled in the art to best utilize the invention.

Referring to FIGS. 1-4, the embodiment illustrated therein includes a pair of lock members 10. Each lock member 10 is preferably formed of a case-hardened steel and includes a hook portion 12 and a shank portion 14. Each hook portion 12 includes an end part 20 and a concave part 22. Each shank portion 14 preferably includes a plurality of selectively positioned holes 16. Lock members 10 are pivotally connected by a rivet 18 or other suitable fastening means so that the shank portions 14 thereof can be made to overlap with each hole 16 in one shank portion registering with a corresponding hole 16 in the other shank portion. When corresponding holes 16 in shank portions 14 are caused to register, the end parts 20 of the hook portions 12 overlap with concave parts 22 thereof facing one another and cooperating to define a continuous lock ring, as shown in FIGS. 1 and 3.

The hook portion 12 of each lock member 10 preferably includes a component, such as a tab 24, which is spaced inwardly from the tip 26 of the hook portion and which is bent over and spaced from the overlapped side 13 of the hook portion so as to form an opening 25 which receives the end part 20 of the opposite hook portion when the holes 16 in shank portions 14 are caused to register. With each end part 20 so received between a tab 24 and connected hook portion 12, the hook portions 12 of the safety lock cannot be laterally separated. In certain embodiments of this invention, it is contemplated that only one of the two hook portions 12 need carry an interlock tab 24.

FIGS. 5 and 6 are illustrative of a modification to the safety lock above described and illustrated in FIGS. 1-4. The hook portion 12 of each lock member includes a pair of confronting tabs 24' which extend from edges 28 and 30 of the hook portion and spacedly overlie the overlapped side 13 of the hook portion. Tabs 24' cooperate to form an opening 25' which receives the end part 20 of the opposite hook portion. Although it is preferable for each hook portion 12 to carry tabs 24', a single pair of the tabs carried by only one of the two hook portions would be sufficient in many applications of this invention to provide the hook portion interlock.

In FIGS. 7 and 8, the end parts 20 of the hook portions 12 of the safety lock illustrated in FIGS. 1-4 are modified by eliminating the tabs 24 and by splitting one end part 20 at its tip 26 so as to provide inner and outer elements 32. One element 32 is preferably bent outwardly and parallel to the plane of overlapped side 13 of the integral hook portion so as to provide an opening 34 into which the other end part 20 is received as the shank portions 14 of the modified safety lock overlap and holes 16 therein are aligned so as to receive the hasp of one or more padlocks.

The safety lock of this invention may be utilized by inserting the hook portions 12 of the lock through an anchoring means, such as an aperture in a switch housing, and around the actuating lever of the switch, and then closing the hook portions by pivotally moving the shank portions 14 until the holes 16 therein register. The hasps of one or more padlocks, each belonging to an individual workman, are then inserted through registering holes 16 and locked.

It is to be understood that the scope of this invention is to extend to those similarly designed safety locks having pivotally connected shanks with a hook portion at each end of the shanks. Additionally, the continuous lock ring formed by the overlapping hook portions 12 need not be circular but can be oval, square, rectangular, or some other shape. The apertures in the shank portions 14 need not be limited to a plurality of corresponding holes 16 but may consist of two corresponding elongated openings.

It is to be understood that the invention herein described is not to be limited to the details herein given but may be modified within the scope of the appended claims.

Claims

What we claim is:

1. A safety lock including a pair of pivotally connected members each having a shank portion and a hook portion, each shank portion having at least one aperture therein, the shank portions being positionable in an overlapping relationship in which the apertures in the shank portions are brought into registry, each hook portion including a concave part and an end part, the concave part of one hook portion confronting the concave part of the other hook portion with the end parts of the hook portions overlapping to define a lock ring when said shank portions are positioned in said overlapping relationship, the improvement wherein each hook portion end part includes a pair of confronting tabs extending from opposite edges of and bent over and spaced from the overlapped part of their hook portion defining an opening between said tabs and overlapped part, each pair of tabs being inwardly spaced from the tip of their hook portion, each hook portion end part being received in the opening formed by and between said tabs and overlapped part of the other hook portion when said shank portions are positioned in said overlapping relationship.

2. A safety lock including a pair of pivotally connected members each having a shank portion and a hook portion, each shank portion having at least one aperture therein, the shank portions being positionable in an overlapping relationship in which the apertures in the shank portions are brought into registry, each hook portion including a concave part and an end part, the concave part of one hook portion confronting the concave part of the other hook portion with the end parts of the hook portions overlapping to define a lock ring when said shank portions are positioned in said overlapping relationship, the improvement wherein the end part of said one hook portion includes a pair of confronting tabs extending from opposite edges of and bent over and spaced from the overlapped part of said one hook portion defining an opening between said tabs and said overlapped part, the end part of said other hook portion being received within said opening and positioned between said tabs and overlapped part when said shank portions are positioned in said overlapping relationship.

3. A safety lock including a pair of pivotally connected members each having a shank portion and a hook portion, each shank portion having at least one aperture therein, the shank portions being positionable in an overlapping relationship in which the apertures in the shank portions are brought into registry, each hook portion including a concave part and an end part, the concave part of one hook portion confronting the concave part of the other hook portion with the end parts of the hook portions overlapping to define a lock ring when said shank portions are positioned in said overlapping relationship, the improvement wherein one hook portion end part is split at its tip and at least partially along the length thereof to form first and second elements, said first element being offset from said said second element to define an opening therebetween, the other hook portion end part being received within said opening and positioned between said first and second elements when said shank portions are positioned in said overlapping relationship.