Electrical circuit breaker safety system

Abstract

A system is provided for preventing a push-pull circuit breaker from being inadvertently depressed. The system may include a clip member having a generally C-shaped collar defining a cylindrical recess therein. The clip member is configured to resiliently expand to be positioned over and receive a cylindrical portion of the circuit breaker knob in a manner that prevents the circuit breaker knob from being depressed to close the circuit breaker. The system further includes first and second tabs depending from ends of the clip member. A cable tie may be positioned through openings formed in the first and second tabs to secure the first and second ends to each other, thereby locking the clip member in position on the push-pull circuit breaker knob and preventing the circuit breaker knob from being depressed.

Claims

1. A system for preventing actuation of a push-pull circuit breaker knob, the system comprising: a clip member having a generally C-shaped collar defining a cylindrical recess therein, wherein the clip member resiliently expands to be positioned over and receive a cylindrical portion of the circuit breaker knob; first and second tabs depending from free ends of the clip member, the first and second tabs forming a restricted opening for which the cylindrical portion of the circuit breaker knob may be snapped into the recess, the first and second tabs having openings therethrough; and a retainer coupled to the first and second tabs in a manner that prohibits the first and second tabs from being urged apart and the clip member from expanding sufficiently to permit removal of the clip member from the circuit breaker knob, thereby locking the clip member in position on the push-pull circuit breaker knob and preventing the circuit breaker knob from being depressed, where each tab forms a substantially concave shape that includes a curved end integrally formed with opposite ends of the clip member, a substantially planar landing portion, and an angled free end opposite the curved end, and where the free end is angled relative to the landing portion to angular dimensions between approximately 10 to 45.

2. The system of claim 1, where the retainer is a cable tie positioned through the openings in the first and second tabs and fastened in a loop to secure the first and second tabs to each other in a manner that prohibits the first and second tabs from being urged apart and the clip member from expanding sufficiently to permit removal of the clip member from the circuit breaker knob.

3. The system of claim 1, where the tabs have a thickness greater than the thickness of the clip member.

4. The system of claim 1, where the free ends of the tabs cooperate to form a substantially V-shaped mouth and a restricted opening into which cylindrical portion of the circuit breaker knob may be snapped.

5. The system of claim 4, where the mouth and restricted opening communicate with the recess to provide a means for urging the tabs apart and guiding the circuit breaker knob into the recess.

6. The system of claim 1, where a tag is coupled to the retainer, the tag bearing safety information.

7. A clip configured to be removably received over a cylindrical portion of a push-pull circuit breaker knob, the clip comprising: a substantially C-shaped collar defining a cylindrical recess therein, the collar being configured to resiliently expand to be positioned over and receive the cylindrical portion of the circuit breaker knob in a manner that prevents the circuit breaker knob from being depressed to close the circuit breaker; and first and second tabs depending from free ends of the collar, the first and second tabs forming a restricted opening for which the cylindrical portion of the circuit breaker knob may be snapped in the recess, the first and second tabs each having an opening therethrough, where each tab forms a substantially concave shape that includes a curved end integrally formed with opposite ends of the collar, a substantially planar landing portion, and an angled free end opposite the curved end, and where the free end is angled relative to the landing portion to angular dimensions between approximately 10 to 45.

8. The clip of claim 7, where the tabs have a thickness greater than the thickness of the collar.

9. The clip of claim 7, where the free ends of the tabs cooperate to form a substantially V-shaped mouth and a restricted opening into which the cylindrical portion of the circuit breaker knob may be snapped.

10. The clip of claim 9, where the mouth and restricted opening communicate with the recess to provide a means for urging the tabs apart and guiding the circuit breaker knob into the recess.

11. The clip of claim 7, where a cable tie is positioned through the openings in the first and second tabs and fastened in a loop to secure the first and second tabs to each other in a manner that prohibits the first and second tabs from being urged apart and the collar from expanding sufficiently to permit removal of the clip from the circuit breaker knob.

12. The system of claim 11, where a tag is coupled to the retainer, the tag bearing safety information.

13. A method for preventing actuation of a push-pull circuit breaker knob, the method comprising: disengaging the circuit breaker knob from its corresponding circuit breaker panel; applying a clip member about an actuating cylindrical portion of the circuit breaker knob, the clip member having a generally C-shaped collar defining a cylindrical recess therein, the clip member being configured to resiliently expand to be positioned over and receive the cylindrical portion; and coupling a retainer to the clip member to secure the clip member to the cylindrical portion of the circuit breaker knob in a manner that prohibits the clip member from being forceably removed from the circuit breaker knob, where coupling the retainer includes snapping the clip member in the cylindrical portion of the circuit breaker knob utilizing first and second tabs that depend from free ends of the clip member, where the first and second tabs form a restricted opening that the cylindrical portion of the circuit breaker knob may be snapped in the recess, the first and second tabs each having an opening therethrough, where each tab forms a substantially concave shape that includes a curved end integrally formed with opposite ends of the clip member, a substantially planar landing portion, and an angled free end opposite the curved end, and where the free end is angled relative to the landing portion to angular dimensions between approximately 10 to 45.

14. The method of claim 13, where the clip member is wedged between a head portion of the circuit breaker knob and the circuit breaker panel to prevent the circuit breaker knob from being depressed to engage the circuit breaker.

15. The method of claim 13 further comprising the step of coupling an indicator to the retainer, the indicator bearing safety information.

16. The method of claim 13 further comprising the step of providing a too for severing the retainer such that the clip member may be removed from the circuit breaker knob.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The present disclosure may be better understood by referring to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the disclosure. In the figures, like reference numerals designate corresponding parts throughout the different views.

(2) FIGS. 1A-1B (Prior Art) are enlarged perspective views illustrating an existing lock-out device in use with push-pull circuit breaker.

(3) FIG. 2 is a top view of an example of a clip member of a system for preventing a push-pull actuating circuit breaker from being depressed, in accordance the present disclosure.

(4) FIG. 3 is a perspective view of the clip member shown in FIG. 2.

(5) FIG. 4A is an enlarged perspective view illustrating how the clip member of FIG. 2 may be installed on a push-pull circuit breaker knob in accordance with the present disclosure.

(6) FIG. 4B is an enlarged perspective view of the clip member of FIG. 2 installed on a push-pull circuit breaker knob in accordance with the present disclosure.

(7) FIG. 5 is a side cross-sectional view of the clip member as shown in FIG. 4.

(8) FIG. 6 illustrates a flow diagram of one example of a method for preventing actuation of a push-pull circuit breaker knob according to the present disclosure.

(9) FIG. 7 is a perspective view of an example of another implementation of a clip member of the present disclosure.

DETAILED DESCRIPTION

(10) FIGS. 2-7 illustrate examples of a system 200 (see FIG. 4) for preventing a powered push-pull actuating circuit breaker from accidentally engaging during the inspection of a structure powered by a circuit. The system 200 includes a clip member 202 and a cable tie 406 (FIG. 4) for retaining the clip member 202 about a knob of the circuit breaker. The disclosed system may be useful in any field in which electrically powered structures are inspected and serviced by field technicians.

(11) FIG. 2 is a top view illustrating one example of the clip member 202. The clip member 202 may include a c-shaped annual collar 204 having a thickness 206, and tabs 208, 210 extending from free ends 212 of the collar 204. The collar 204 includes an inner wall 214 defining a circular recess 216 therein. In some implementations, the collar 204 may have a thickness 206 of between 0.05 and 0.1 inches, and more preferably 0.06 inches and the inner wall 214 may be constructed to diametrical dimensions of approximately between and inches, or such other dimensions suitable to correspond to the dimensions of a push-pull circuit breaker knob.

(12) The clip member 202 may be made from acrylonitrile-butadiene-styrene copolymer (ABS) plastic or any other material having similar pliant and electrically non-conductive properties. More specifically, the clip member 202 can be made of material that enables the collar 204 to flex outward as force is applied to the tabs 208, 210 apart to spread them apart, for example, when the tabs 208, 210 are engaged by the circuit breaker knob, as discussed in detail below. In certain implementations, the clip member 202 may comprise safety warning colors, such as red, to indicate to a technician that the circuit breaker knob about which the clip member 202 is secured is disengaged from the circuit breaker panel.

(13) Each tab 208, 210 may form a substantially concave shape that includes a curved end 218 integrally formed with the opposite ends 212 of the collar 204, a substantially planar landing portion 220, and an angled free end 222 opposite the curved end 218. The free end 222 may be angled relative to the landing portion 220 to angular dimensions between, for example, approximately 10 to 45. In this way, the opposing tabs 208, 210 may be identical in dimensions and shape such that the landing portions 220 of the tabs 208, 210 mate and are capable of bearing against one another.

(14) The free ends 222 of the tabs 208, 210 cooperate to form a substantially V-shaped mouth 224 and restricted opening or throat 226 into which a stem of the circuit breaker knob may be snapped. The mouth 224 and throat 226 communicate with the recess 216 to provide a means for urging the tabs 208, 210 apart and guiding the circuit breaker knob into the recess 216. The tabs 208, 210 may be constructed to a thickness equal to or greater than the thickness of the collar 204 to provide greater structural strength against shearing forces as tabs 208, 210 are urged apart by the circuit breaker knob and, further, to ensure that the tabs 208, 210 are capable of engaging one another when the circuit breaker knob is installed within the recess 216. For instance, and by way of example only, the clip member 202 may be constructed with a collar thickness 206 of 0.6 inches and tab 208, 210 thicknesses of 0.08 inches.

(15) FIG. 3 is a perspective view the clip member 202. As shown the collar 204, for example, may have a height 302 between and inches. A suitable height 302 for enabling the collar 204 to fit between a head portion of the circuit breaker knob and a housing portion of the circuit breaker may be 0.30 inches. At any event, the collar 204 should be constructed to a height sufficient to prevent the circuit breaker knob from being depressed.

(16) As further shown, each tab 208, 210 may include a slot 304 of suitable dimensions to pass a cable tie therethrough. In certain implementations, upper and lower surfaces 306, 308 of the collar 204 and the free ends 222 of the tabs 208, 210 may be chamfered or rounded to eliminate any sharp edges.

(17) FIGS. 4A-4B are enlarged perspective views and FIG. 5 is a cross section view illustrating the installation of the clip member 202 on a knob 402 of a push-pull circuit breaker 400. As best shown in FIG. 5, each breaker 400 is mounted on a panel 404 so that the knob 402 projects from the panel 404 for actuation. The circuit breaker knob 402 includes a head portion 502 and a stem 504 that actuates into and out of an annular housing 506 coupled to the circuit breaker panel 404.

(18) During installation of the clip member 202 over the breaker knob 402, the breaker knob 402 must be disengaged from the breaker panel 404 (i.e., the head portion 502 must be disengaged from the housing 506) so the clip member 202 may be manually snapped onto the stem 504 of the breaker knob 402. When the breaker knob 402 is disengaged from the breaker panel 404, the stem 504 is retained within breaker housing 506 by a stop 508. As shown in FIG. 4A, the tabs 208, 210 of the clip member 202 must be spread apart to allow the knob to be received in the recess 216 of the clip member 202, through the mouth 224.

(19) Referring back to FIG. 5, when installed, the collar 204 is disposed between the head 502 and the breaker housing 506 to restrict the actuation of the breaker knob 402. The collar 204 may be constructed to a sufficient height 302 to prevent the breaker knob 402 from being depressed. For example, the collar 204 may be constructed to a height having an interference fit between the head 502 and the breaker housing 506.

(20) Once the clip member 202 is snapped into place over the breaker knob 402, a self-locking cable tie 406, otherwise known as a panduit strap, is looped through the slots 304 of the tabs 208, 210 (shown also in FIG. 4B) and secured in a looped configuration to secure the restricted opening 226 (FIG. 2) and prevent tabs 208, 210 from being pried or urged apart and the clip member 202 from expanding sufficiently to permit removal of the clip member 202 from the circuit breaker knob 402. Thus, when force is applied to the head 502 to push the knob 402 into engagement, the collar 204, trapped between the head 502 and the breaker housing 506, prevents the knob 402 from moving. When the cable tie 406 is secured within the slots 304 of the tabs 208, 210, the only way the clip member 202 may be removed from the breaker knob 402 is by cutting the cable tie 406 with a cutting tool.

(21) It is well understood that a push-pull circuit breaker only engages when the breaker knob 402 is pressed all the way into the breaker panel 404. Most push-pull circuit breakers have an indicator in the form of a white ring or strip that is striped about the stem of the knob. When a knob is disengaged (i.e., pulled out), the white ring indicates that the circuit breaker is open. So when the breaker 400 is open, power comes to the breaker 400, but it does not go through the breaker 400 to power the structure or device (not shown) electrically coupled to the breaker. It is not until the knob 402 (i.e., the head portion 502) is fully engaged with the breaker panel 404 (i.e., breaker housing 506) that the circuit breaker 400 is closed and electrical current is permitted to flow to the structure or device.

(22) Under the LOTO standards, lock-out devices must be tagged with a serial number, for identification, and a warning decal must be attached to the device. Therefore, in certain implementations, as shown in FIG. 4B, a warning tag 408 with serial numbers may be coupled to the cable tie 406. In some implementations, the warning tag 408 may comprise an elongated (e.g., rectangular) shaped placard with safety colors, such as, for example, a solid red background with white lettering. The lettering may include the signal wording such as WARNING or DANGER, in addition to serial number(s) identifying the circuit breaker unit, or the structure or device coupled to the circuit breaker unit, and the person performing the lock and tag. In other implementations, the warning tag may be a paper tag embossed with appropriate safety information.

(23) With reference now to FIG. 6, an exemplary method for preventing the actuation of a push-pull circuit breaker knob is illustrated in flow diagram 600. The method begins by disengaging the circuit break knob from its corresponding circuit breaker panel (step 602). Next, a clip member is applied about an actuating cylindrical portion of the circuit breaker knob (step 604). The clip member includes a generally C-shaped collar defining a cylindrical recess therein, where the clip member is configured to resiliently expand to be positioned over and receive the cylindrical portion of the circuit breaker knob.

(24) A retainer is then coupled to the clip member to secure the clip member to the cylindrical portion of the circuit breaker knob in a manner that prohibits the clip member from being forceably removed from circuit breaker knob (step 606). In step 606, the clip member is wedged between a head portion of the circuit breaker knob and the circuit breaker panel to prevent the circuit knob from being depressed to engage the circuit breaker. Finally, a safety tag bearing safety information may be coupled to the retainer at step 608.

(25) The safety system 200 of the present disclosure provides several advantages over existing lock-out devices. First, the lock-out device, i.e., the clip member 202, of the present disclosure is low-profile and does not protrude beyond the circuit panel 404. Thus, the clip member 202 is less likely to broken as a result of being bumped or caught by objects or article of clothing worn by a serving technician, therefore, minimizing the cost of replacing broken circuit breakers knobs.

(26) Second, the lock-out system of the present disclosure comprises only a single part, as opposed to the multi-part construction of existing lock-out devices. Therefore, reducing the risk of FOD damage and other potential issues.

(27) Further, different sizes of lock-out devices are typically used for high-powered and low-current circuit breakers. Lock-out systems of the present disclosure may be used in each application without varying the dimensions of the clip member or its design.

(28) FIG. 7 is a perspective view of an example of another implementation of a clip member 700 of the present disclosure. According to this implementation, the clip member 700 includes a flange 704 coupled to an under and/or top surface of the collar 702. In other implementations, the flange 704 may be coupled to both the under and top surfaces of the collar 702. The flange 704 may enhance the structural soundness of the clip member 700 and, further, enables the member to be made from lightweight and fairly inexpensive material, such as plastic. The flange 704 also provides a bearing surface for absorbing the compression loads placed on the collar 704.

(29) While the foregoing implementations of the present disclosure are described in use in commercial aircraft structures, the present disclosure may also apply to military aircraft, spacecraft, missile systems, commercial structures, and other applications where push-pull circuit breakers are used to power equipment, circuits, or machines. In general, terms such as attached to, coupled to, and configured for coupling to and secured to (for example, a first component is coupled to or is configured for coupling to or is secured to a second component), or communicate (for example, a first component communicates with or is in communication with a second component) are used in this application to indicate a structural, functional, mechanical, electrical, signal, optical, magnetic, electromagnetic, ionic or fluidic relationship between two or more components (or elements, features, or the like). As such, the fact that one component is said to couple to a second component is not intended to exclude the possibility that additional components may be present between, and/or operatively associated or engaged with, the first and second components.

(30) Although the previous description only illustrates particular examples of various implementations, the present disclosure is not limited to the foregoing illustrative examples. A person skilled in the art is aware that the disclosure as defined by the appended claims can be applied in various further implementations and modifications. In particular, a combination of the various features of the described implementations is possible, as far as these features are not in contradiction with each other. Accordingly, the foregoing description of implementations has been presented for purposes of illustration and description. Modifications and variations are possible in light of the above description.