In some circumstances it may be necessary to restrain a switch from being turned on or off. For example, rules promulgated by the Occupational Safety and Health Administration (OHSA) require an electrical circuit breaker to be “locked-out,” i.e., restrained from being switched from an off position to an on position, for safety purposes to allow an individual to repair or install electrical equipment powered via the circuit breaker.
Manufacturers of electrical circuit breakers have developed a variety of devices for restraining individual circuit breaker switches. One such device disclosed in U.S. Pat. No. 4,347,412 is illustrated herein in
Manufacturers may design the housing and switch handle of a circuit breaker switch such that only their respective restraint devices can interface therewith. For example, the housing may have a lip, groove, or ridge at a fixed distance from the switch handle such that the manufacturer's restraint device may be compatible with the circuit breaker switch, but restraint devices produced by competing manufacturers may not. A risk exists that an individual may place an incompatible restraint device on a circuit breaker resulting in failure of the restraint device and potential injury to the individual. Another problem with available switch restraint devices is their bulkiness. U.S. Pat. Nos. 5,079,390 and 5,147,991 each disclose a circuit breaker restraint device having a member whose width is equal to that of a switch handle. The large size of these restraint devices requires a significant amount of material and raises the cost of the restraint device. Moreover, the size of such devices may impede the ability of a user to close the outer door to the circuit breaker box. A need, therefore, exists for a universal switch restraint device that can be used without modification with a multiplicity of brands of circuit breakers.
The present invention relates to the field of electrical systems and repairs thereof. In particular, the present invention relates to a device that can be secured to a switch handle to inhibit the handle from moving relative to the switch.
In one aspect of the invention, a universal breaker lock device for a switch handle that projects through an aperture in a switch housing is presented. The universal breaker lock device comprises a collar member forming a channel therethrough and adapted to engage the switch handle. A blocking member extends from the collar member and is configured to contact the switch housing external to the aperture when the collar member engages the switch handle. A cover member is attached to the blocking member, and has open ends. The cover member further includes a pair of apertures disposed opposite each other. A lock can be disposed through the pair of apertures.
In another aspect of the invention, a universal breaker lock device for a switch handle is presented. The universal breaker lock device comprises a channel adapted to accommodate the switch handle and having first and second planar ends. A lever arm extends from the channel a distance greater than the greatest dimension measured transversely across the channel. A cover member is attached to the lever arm, and has open ends. The cover member further includes a pair of apertures disposed opposite each other. A lock can be disposed through the pair of apertures.
In a further aspect of the invention, a universal breaker lock device for a switch handle is presented. The universal breaker lock device comprises a channel adapted to accommodate the switch handle. The channel includes a base wall, first and second side walls that extend generally perpendicularly from the base wall, and first and second feet that extend toward one another from distal ends of the first and second side walls. The channel includes a width defined by a distance measured between the first and second side walls. A lever arm extends from the base wall a distance greater than the width of the channel. A cover member is attached to the lever arm, and has open ends. The cover member may further include a structure that facilitates addition of an external locking device, such as a keyed or combination lock, to the cover member to further limit access for removal of the breaker lock device. For example, a pair of apertures disposed opposite each other may be provided to permit the hasp of a lock to pass through the apertures and lock the cover to prevent removal of the breaker lock device from the circuit breaker.
Other aspects and advantages of the present invention will become apparent upon consideration of the following detailed description, wherein similar structures have similar reference numerals.
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The channel 86, 86a includes first and second ends 106, 108 that are each generally planar, as illustrated in
The channel 86 of the collar member 82 may be dimensioned to form a press fit with the switch handle 76. For example, the surfaces 102 and an interior surface 110 of the base wall 90 of the collar member 82 may be in flush contact with the surfaces 104 and 88 of the switch handle 76, respectively, and/or interior surfaces 112, 114 of the side walls 92, 94 may be in flush contact with lateral surfaces 116 of the switch handle 76. Similarly, the channel 86a of the collar member 82a may be dimensioned to form a press fit with the switch handle 76 via flush contact between the surfaces 88 and 110 and between the surface 104 and an interior surface 102a of the top wall 98a.
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The blocking member 84 extends away from the collar member 82, 82a generally in the direction of motion of the switch handle 76 that the universal breaker lock device 70, 70a is configured to prevent. The blocking member 84 has a long dimension or length, L, measured between a proximal end 120 attached to the base wall 90 and a distal end 122 of the blocking member 84. The channel 86 has a greatest internal dimension measured transversely across the channel 86 between opposite internal surfaces thereof. For example, the greatest transverse internal dimension of the channel 86 may be a width, W, measured between the interior surfaces 112, 114 of the side walls 92, 94, as illustrated in
The length L of the blocking member 84 is configured to be a length greater than the greatest transverse internal dimension W, W′ of the channel 86, 86a, respectively. This configuration provides a blocking member sufficiently long to make contact with the switch panel 80 exterior to the aperture 78 so long as the channel 86, 86a fits over the switch handle 76. Furthermore, more contact between the blocking member 84 and the switch panel 80 may increase friction therebetween and prevent slippage of the universal breaker lock device 70, 70a relative to the electrical switch 72.
The blocking member 84 has a short dimension, S, measured transverse to the long dimension L. The short dimension, S, may be configured to be less than the greatest transverse internal dimension of the channel 86, 86a, as illustrated in
In other embodiments, in addition to or instead of being configured substantially parallel to the first end 106, the blocking member 84 may form an angle with the first end 106. An angled blocking member 84 may be useful in some circumstances given the geometry and/or contours of the switch housing 74, which may vary between brands of electrical switches 72.
Not wishing to be bound by theory, the blocking member 84 acts as a lever arm that provides a reaction moment in response to rotational movement of the switch handle 76. Any force applied to move the switch handle 76 from the ON position to the OFF position (or vice versa depending on the configuration of the universal breaker lock device 70, 70a and switch handle 76) causes the switch panel 80 to produce an equal and opposite reaction force in the blocking member 84 that substantially eliminates movement of the switch handle 76. The blocking member 84 transfers this reaction force to the switch handle 76 via the collar member 82, 82a, which operatively grips the switch handle 76 when a force is applied to move the switch handle 76.
The interior surface 110 of the base wall 90 may contact the surface 88 of the switch handle 76. The interior surface 110 may be positionally adjustable such that an interior dimension measured between the interior surface 110 and surfaces 102, 102a may be altered to allow the collar member 82, 82a to be able to universally grip a variety of switch handles 76 having a variety of shapes and sizes.
Alternatively, an adjustable fastener 124, such as, for example, a set screw, may extend through a threaded aperture 126 disposed through the base wall 90 and impinge the surface 88 of the switch handle 76. The distance that the fastener 124 extends into the channel 86, 86a may be adjusted by rotating the fastener 124 through the threaded hole 126. The fastener 124 creates friction between the collar member 82, 82a and the switch handle 76 to increase the effectiveness of the grip there between. Additionally, the fastener 124 transfers the hereinabove described reaction force produced in the blocking member 84 to the surface 88 of the switch handle 76 thereby inhibiting movement of the switch handle 76.
The adjustability of the fastener 124 allows the universal breaker lock device 70, 70a to be operational with a multiplicity of available brands of electrical switches 72 having a switch handle 76 as large as the maximum size of the channel 86, 86a. The fastener 124 may be fixed in a predetermined position relative to the collar member 82, 82a by a locking mechanism as described in U.S. Pat. Nos. 5,079,390 and 5,147,991, which are hereby incorporated by reference in their entireties.
The adjustability of the universal breaker lock device 70, 70a not only allows for utility on a wide range of switch handle shapes and sizes but also allows a user to quickly and simply restrain an electrical switch from being actuated. This flexibility and ease of installation may save time in comparison to more complex devices intended only for tamper proof or more permanent installation. The universal breaker lock device 70, 70a described hereinabove may require less material to manufacture than known larger and bulkier breaker lock devices, thereby providing an economical benefit in cost of material. Further, the open nature of the second end 108 of the channel 86, 86a allows a user to see indicia such as brand, model, or amperage rating that may be printed or embossed on a distal end of the switch handle 76.
While the present invention may be embodied in many forms, multiple embodiments are discussed herein with the understanding that embodiments illustrated are to be considered only as an exemplification of the invention and are not intended to limit the disclosure to the embodiments illustrated. For example, although the universal breaker lock device 70, 70a is described hereinabove with regard to a circuit breaker switch, the universal restraint device 70, 70a is also operable with wall mounted light switches. Further, it should be understood that the universal breaker lock device 70, 70a is not limited to use with electrical switches. The universal breaker lock device 70, 70a can be dimensioned to operate with any manual switch adapted to be selectively displaced in an ON or OFF position. It should be understood that the universal breaker lock device 70, 70a can engage a switch in both an upright and inverted position to prevent downward and upward movement, respectively, of the switch handle 76.
A universal breaker lock device for a switch handle is presented that includes an adjustable collar member and a lever arm that is sized to be longer than a maximum internal transverse dimension of the collar member. The universal breaker lock device further comprises a cover member adapted to receive a locking element which prevents adjustment of the device while in use. The configuration and length of the lever arm and the adjustable size of the collar member allow the universal restraint device to be quickly and easily applied to a variety of switch handle shapes and sizes.
Numerous modifications to the present invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only and is presented for the purpose of enabling those skilled in the art to make and use the invention and to teach the best mode of carrying out same. The exclusive rights to all modifications which come within the scope of the appended claims are reserved. All patents, patent publications and applications, and other references cited herein are incorporated by reference herein in their entirety
This application is a continuation-in-part application of co-pending, commonly owned U.S. patent application Ser. No. 12/902,069, filed Oct. 11, 2010, which claims priority to U.S. Provisional Patent Application Ser. No. 61/251,195, filed Oct. 13, 2009, each of which is hereby incorporated by reference in their entirety.
Number | Date | Country | |
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61251195 | Oct 2009 | US |
Number | Date | Country | |
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Parent | 12902069 | Oct 2010 | US |
Child | 13765571 | US |