US3354284A - One-half width circuit breaker mounting means - Google Patents

Description

Nov. 21, 1967 G. w. KNECHT 3,354,284

ONE-HALF WIDTH CIRCUIT BREAKER MOUNTING MEANS Filed March 2, 1966 INVENTOR. 660/?66 M /(1/CH 7 M WX ax AW;

A T TORNE United States Patent 3,354,234 ONE-HALF WIDTH CIRCUIT BREAKER I MOUNTING MEANS George W. Kneeht, Brooklyn, N.Y., assignor to Murray Manufacturing Corporation, Brooklyn, N.Y., a corporation of New York Filed Mar. 2, 1966, Ser. No. 531,259 4 Claims. (Cl. 200-168) ABSTRACT OF THE DISCLOSURE A resilient leaf for mounting a circuit breaker 'of the type used on a mounting panel including a flange having an inverted L-shaped cross section. The leaf extends from one lower corner of the breaker and has an upstanding sharp edge which may pass under the L-shaped portion when the breaker is angularly inserted, and which engages the underside when the breaker is seated, thereby preventing its movement.

This invention relates to circuit breakers and in particular to an arrangement coacting between the circuit breaker and the panelboard for mounting the former on the latter.

The conventional load center, for home and light industrial application, comprises two or more power buses from which bus blades project in a parallel array; the blades of the buses being alternated so that neighboring blades are associated with opposite polarity buses. The spacing between adjacent blades is approximately one inch and is designed to accommodate the standard oneinch width circuit breaker.

Several years ago, half-inch width circuit breakers made their appearance on the market, and while panelboards may be constructed specifically to utilize what will be hereinafter referred to as half-width breakers, it is highly desirable to utilize existing panelboards adapted for standard width breakers.

The conventional circuit breaker, be it single or double pole, is designed with a receptive contact clip centered at the lower front corner. When applied to a bus blade, the breaker sits astride the blade with a contact clip gripping its opposite sides and one-half of the breaker width overhanging the blade on either side. Since a neighboring unit is likewise disposed on a bus blade one inch away, the two units are contiguous. The innovation of half-width breakers does not necessarily double the circuit breaker capacity of a given load center or panelboard. This arises because of the fact that if the half-width breaker sits astride a bus bar blade as did the conventional one-inch breaker, the additional space saved is not utilized. One arrangement for efiiciently utilizing this space is, however, shown in copending application Ser. No. 405,353, filed October 21, 1964, now Patent No. 3,283,110, to the same assignee. With this arrangement, half-Width breakers include side-wiping contacts which, by virtue of a special adapter sitting astride the bus bar stab, may be positioned either to the left or the right of the circuit breaker. In this manner, two circuit breakers may be placed between adjacent stabs, each breaker making electrical contact with the outside stab. It has been found, however, that with conventional means for seating the breaker in the panelboard, the use of the adapter (described in the patent) may be defeated by the simple experient of inserting an object into the breaker to force the side-wiping contact to the appropriate side. This, needless to say, could be quite hazardous.

A further consideration which arises from the substitution of half-width circuit breakers in a panelboard designed for use with standard width breakers is the means for mounting the breaker end opposite that at which the side wiping electrical contact is made in such a manner as to preclude slippage of the breaker either laterally or longitudinally.

Accordingly, it is the object of this invention to provide an arrangement for mounting circuit breakers in a panelboard or load center to preclude slippage of the breaker either longitudinally or laterally.

It is a further object of this invention to provide a circuit breaker mounting means which coacts with the panelboard to preclude the insertion of foreign objects in an attempt to defeat the necessity for the prescribed elements.

It is a still further object of this invention to provide visual means for indicating that such an unauthorized attempt has been made.

The above mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will best be understood by reference to the following description of an embodiment of the invention taken in conjunction with the acompanying drawings wherein:

FIG. 1 is a perspective illustration of a standard halfwidth circuit breaker according to the invention in conjunction with the panelboard mounting means for accommodating these breakers;

FIG. 2 illustrates the use of the inventive breaker with different panelboard mounting means;

FIGS. 31a and 3b are plan and partial elevation views, respectively, of conventional and half-width breakers in mounted position upon a panelboard;

FIGS. 4a and 4b are sectional views of the inventive mounting means during the initial and final seating of the breaker respectively.

Turning now to the figures and in particular to FIG. 1, there may be seen the conventional standard width breaker A, the foot end of which is shown ready to mount on the panelboard mounting means 10. The bus bar stabs 12, 13 and 14 are alternately associated with dilferent polarity buses as previously mentioned; for simplicity, only the tops of the stabs are shown. With the conventional arrangement, the front end of breaker A (not shown) sits astride bus bar stab 12 after the foot end has been located as will be described. To position the foot end of conventional breaker A, the breaker cavity 16 is positioned over the inverted L-shaped flange 17; the breaker being angularly rotated to sit astride the blade 12. Lateral displacement of the breaker is precluded by the side of cavity 16 abutting upon the sides of the flange 17.

The breaker of the type to which the invention is directed is depicted as B in FIG. 1. As may be seen, the front end of this breaker includes a side wiping contact 11 which emerges through a window 15 to bear against the rear side of bus bar stab 14. The relative position of the front end of this breaker, as well as the means for affording sufficient side wiping contact pressure, is provided by an adapter (described in patent application Ser. No. 405,353, filed Oct. 21, 1964). Since the invention does not depend upon the precise manner in which the front end of the breaker is retained in sidewiping position, for the sake of brevity, the adapter has been omitted from this application. Sullice to say, however, that some means are afforded for retaining the front end of the breaker in position with stab 14 and contact 11 in wiping engagement and an exemplary means may be seen by reference to the above patent application.

The modification of the breaker according to the invention may be seen in the lower front corner and essentially comprises the adjunct 20, a portion of which is shown in this figure. Before analyzing this element in detail, its function relative to the conventional panelboard mounting means, as well as to the modified panelboard mounting means shown in FIG. 2 will be discussed. Ele- 9 o) ment 2b, as may be seen, is forked, the separate branches being resilient perpendicular to the plane of their faces.

When this element is inserted under the flange 19, and the breaker is angularly displaced in a manner similar to that of breaker A explained above (to seat the side wiping contact end), a portion a of element 20 resiliently contacts one portion of the flange 19, retaining it in position in a manner to be described.

FIG. 2 shows an alternative panelboard arrangement which may also be utilized with the invention. As may be seen by comparison between the respective panelboard foot mounts 17, 18 and 19 in FIG. 1 and 23 in FIG. 2, the latter mounts are continuous and it is not required that they be individually lanced, such as shown in FIG. 1 in order to function. This, needless to say, arises as a consequence of the fact that whereas the conventional arrangement utilizes cavities, the invention employs an element which extends out of the breaker and therefore does not require mating means to enter a cavity. It is preferable with the arrangement shown in FIG. 2 that the areas where the foot end of the breaker is to be located be marked (such as in the black and white fashion shown) so that visual location of the foot end of the breaker may beachieved.

FIGS. 4a and 4b illustrate the manner in which the lower end of the breaker is located With respect to the panelboard. In FIG. 4a the breaker is shown with one fork 20a of leaf 20 being inserted under the inverted L-shaped flange 19. As may be seen in this figure, no contact occurs at this point between the leaf and the panelboard flange. As also may be seen from this figure, leaf 20 is C-shaped with the portion 20 entering the cavity 27 within the breaker to add resilience and retain the leaf in position. When the breaker is angularly displaced about the fulcrum as shown in FIG. 4b, the perpendicular serration on portion 20a is brought to bear against the underside of the flange 19. Preferably, the leaf is made of a rather hard metal so that the serrated points (better seen in FIG. 1) may slightly penetrate the underside of the flange, retaining the foot end of the breaker in position. Because of this contact force, if the front end of the breaker is not retained in position by means-of the adapter previously mentioned (not shown) but rather some implement is utilized to circumvent the use of the adapter, the torque force upon the circuit breaker via the resiliency of the leaf 20 and fulcrum 25 will cause the front end to rise; i.e. in FIG. 4b the breaker will rotate counterclockwise. Thus, a visual indication will be given the user that the method he has chosen to mount the breaker is an incorrect one and hazardous.

FIGS. 3a and 3b show top and end views of one conventional and three half width circuit breakers mounted upon a panelboard. The conventional breaker is shown as in normal use sitting astride the bus blade 12 with the flange 17 disposed in the breaker cavity. The breakers 13 and C are juxtaposed half-width breakers, each sitting on either side of bus stab 13, the internal front portions of the breakers including facing contacts 11 and 11' for the corresponding opposite blade faces. As may be seen most clearly in the partial end view, one branch of each of the mounting elements 20 and 20 is flexed beneath the underside of the inverted L-shaped flange 18.

Half-width breaker D is shown in FIGS. 3a and 3b to illustrate an alternative arrangement for locating the foot end of the half-width breakers with respect to the panel mounts. In this case, the breaker is provided with a pair of abutting surfaces 21 and 22 for engaging one of the correspondingly denoted (and primed) panelboard flange abutments 2i and 22 on flange 19. The foregoing results in a physical rather than a visual (as shown in FIG. 2) positioning of the foot end of the breaker.

While the principles of the invention have been described in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of the invention as set forth in the objects thereof and in the accompanying claims.

What is claimed is:

1. In a circuit breaker of the type used with a mounting panel, including a flange having an inverted L-shaped cross-section, the improvement therein comprising: a resilient leaf extending from one end of the breaker for entering the inverted L-shaped portion of said mounting panel without substantial contact; and a sharp relatively hard edge upstanding from the external edge of said leaf, said edge normally contacting the underside of said L- shaped mounting panel member when said breaker is seated, whereby said breaker must be angled for entry of said leaf under said inverted L-shaped mounting panel member and then angularly displaced to the normal seated position whereupon the edge of said leaf engages the underside of said member, preventing lateral or longi tudinal movement of said breaker.

2. The improvement claimed in claim 1 wherein said leaf i forked and includes two upstanding edges.

3. The improvement claimed in claim 2 wherein said breaker and mounting panel include cooperating means for physically locating the end of said breaker at which the leaf is located.

4. The improvement claimed in claim 1 wherein said leaf is of C-shaped cross-section and is retained within an L-shaped cavity in said breaker.

References Cited 7 UNITED STATES PATENTS 3,172,014 3/1965 Johnson .3l7- 1l9 3,289,049 11/1966 Middendorf 200168 ROBERT K. SCHAEFER, Primary Examiner. H. O. JONES, Assistant Examiner.

Claims (1)

1. IN A CIRCUIT BREAKER OF THE TYPE USED WITH A MOUNTING PANEL, INCLUDING A FLANGE HAVING AN INVERTED L-SHAPED CROSS-SECTION, THE IMPROVEMENT THEREIN COMPRISING: A RESILIENT LEAF EXTENDING FROM ONE END OF THE BREAKER FOR ENTERING THE INVERTED L-SHAPED PORTION OF SAID MOUNTING PANEL WITHOUT SUBSTANTIAL CONTACT; AND A SHARP RELATIVELY HARD EGE UPSTANDING FROM THE EXTERNAL EDGE OF SAID LEAF, SAID EDGE NORMALLY CONTACTING THE UNDER SIDE OF SAID LSHAPED MOUNTING PANEL MEMBER WHEN SAID BREAKER IS SEATED, WHEREBY SAID BREAKER MUST BE ANGLED FOR ENTRY OF SAID LEAF UNDER SAID INVERTED L-SHAPED MOUNTING PANEL MEMBER AND THEN ANGULARLY DISPLACED TO THE NORMAL SEATED POSITION WHEREUPON THE EDGE OF SAID LEAF ENGAGES THE UNDERSIDE OF SAID MEMBER, PREVENTING LATERAL OR LONGITUDINAL MOVEMENT OF SAID BREAKER.

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