US3749873A - Circuit breaker housing - Google Patents

Abstract

Disclosed is an electrical circuit breaker having an improved case construction. The case comprises three principal elements made of suitable thermoplastic and snapped together without separate fasteners or adhesive, namely, a rocker actuator, a housing, and a base. The actuator may be provided with a light and one or more of the plastic elements may be suitably colored. A removable auxiliary terminal plug is provided in the base and the terminals are retained by turned-over tabs after insertion.

Description

United States Patent 11 1 I Harper et al.

[11] 3,749,873 14 1 July 31,1973

1 CIRCUIT BREAKER uousinc [75] inventors: George S. Harper, Cambridge; John Richard Shand, Easton, both of Md.

[7 3] Assignee: Airpax Electronics Incorporated,

Cambridge, Md.

[22] Filed: Aug. 18, 1971 [21] Appl. No.: 172,632

[52] U.S. Cl. 200/168 R, 335/202 [51] Int. Cl. H0111 9/02 [58] Field of Search 200/172 R,l72 A, 200/153 T, 166 CT, 168 C, 167 A, 168 R; 335/64, 202

[56] References Cited UNITED STATES PATENTS 3,626,338 12/1971 Nicol et al. 335/202 3,609,268 9/1971 Sanchez 200/167 A 3,103,570

9/1963 Gibbs .1 2001172 A 3,466,413 9/1969 Sharples ZOO/168 C Primary Examiner-Herman J. l-lohauser 9 Assistant Examiner-William J. Smith Attorney-LeBlanc & Shut [57] ABSTRACT Disclosed is an electrical circuit breaker having an improved case construction. The case comprises three principal elements made of suitable thermoplastic and snapped together without separate fasteners or adhesive, namely, a rocker actuator, a housing, and a base. The actuator may be provided with a light and one or more of the plastic elements may be suitably colored. A removable auxiliary terminal plug is provided in the base and the terminals are retained by turned-over tabs after insertion. v

5 Claims, 9 Drawing Figures PATENIEDJULS H975 3'749'873 sum 1 0r 2 INVENTORS. GEORGE S. HARPER J. RICHARD SHAND BY jl v'e, a f

ATTORNEYS.

'Pmmniuwm 3,749,873 4 SHEET 2 BF 2 FIG. 6 FIG] I00 -E/QB 'l 9 i 24 24 4 r 1' .FIG.9 n2 fi uz INVENTORS & GEORGE s. HARPER J. RICHARD SHAND ATTORNEYS.

CIRCUIT BREAKER HOUSING 1 This invention relates to electrical circuit breakers and more particularly to an improved circuit breaker housing for electromagnetic circuit breakers.

Electromagnetic circuit breakers have been used for many years to interrupt and protect a variety of electrical circuits. These breakers generally comprise an overcurrent coil wrapped around a magnetic core, ei-

ther with or without a hydraulic time delay tube. A contact bar carrying a movable contact is actuated by a manually operated handle through a collapsible toggle to move the contact between the open and closed positions. The toggle is conventionally provided with a trip mechanism engaged by an armature adjacent the overcurrent coil so that an overload current through the coil attracts the armature, consequentially tripping the toggle which collapses to open the contacts automatically. The circuit breakers may be single pole or multiple pole devices in which latter case individual poles of the multipole unit are often interconnected either through the handles or by an internal mechanism such as a comonon trip bar.

In the past, circuit breakers have been largely considered purely utilitarian and used only as protective devices. The breakers are customarily made of a black electrically insulating material, such as phenolic, with little consideration being given to the breaker appearance. 1

The present invention is directed to an improved breaker construction and more particularly 'to an improved breaker case having a more pleasing appareance so that the aesthetic qualities of the breaker are improved when it is placed for viewing on the front panel of electrical equipment. Thebreaker canserve as a protective device, an on-off switch, and a pilot light. Through the use of an improved assembly technique and improved case materials, it is possible to provide the case in various colors and color combinations for improved appearance. In addition, the new materials make possible economies in manufacture.

The circuit breaker case is formed essentially of three separate parts which are assembled by snapping them together without the use of rivets or the like. The lower case section telescopes within the upper case section and because of the resiliency of the plastic materials from which the case may be made, these two sections are snapped together. The third principal component of the case, also made of plastic, is the manual actuator which is also snapped into the upper or front portion of the case. Addtional features include an optional snapin or flush mounting construction for the panel in which the circuit breaker is placed, as well as an illuminated handle and an improved arrangement for holding a plug in the lower case section as well as an improved terminal assembly. The circuit breaker may be provided in eitherone pole or multipole versions with single rocker actuation. The snap-together-assembly elirne inates the need for rivets, epoxy, or the like, and the plastic materials used make possible improved panel appearance through the selection of appropriate colors or color combinations. The breaker can be used as an on-off switch, control device, manually reset relay, and pilot light, in addition to circuit breaker protection.

It is therefore one object of the present invention to provide an improved electrical circuit breaker.

Another object of the present invention is to provide an improved electrical circuit breaker case.

and the like.

Another object of the present invention is to provide an improved circuit breaker construction having a novel snap-in manual actuator.

Another object of the present invention is to provide a circuit breaker having an improved plug and terminal mounting construction.

These and further objects and advantages of the invention will be more apparent upon reference to the following specification, claims, and appended drawings, wherein: l

FIG. 1 is an exploded view of an electromagnetic circuit breaker case constructed in accordance with the present invention; i

FIG. 2 is aside view 'of the assembled case with portions broken away for the sake of clarity;

FIG. 3 is a partial cross section-through the circuit breaker case taken along line 3-3 of FIG. 2;

FIG. 4 shows an electromagnetic circuit breaker having acase constructed in accordance'withFIGS. 1-3 snap-mounted into a circuit breaker panel;

FIG. 5 shows the circuit breaker of the present invention flush mounted to a circuit breaker panel;

' FIG. 6 shows a multipole or two-pole circuit breaker constructed in accordance with the present invention;

FIG. 7 is an inside plan view showing the base-of the circuit breaker casing of the present invention provided with an auxiliary switch plug;

FIG. 8 is a cross section taken along line 8-8 of FIG. 7; and I FIG. 9 is a cross section taken at right angles to that of FIG. 8 along line 9-9 of FIG. 7.

Referring to the drawings, the novel circuit breaker of the present invention is generally indicated at 10 in FIGS. 4 and 5 and comprises acircuit breaker housing 12, shown in exploded view in FIG. 1, and comprising three sections, namely, a lower section orbase 14, an upper section orhousing 16, and a snap-inmanual actuator 18. The inner operating mechanisms of the circuit breaker are not shown and these maybe of conventional constructions,such as those shown by way of example only'in'assignee's U.S. Pat. Nos. 3,412,351;

r 3,444,488 and 3,497,838, the disclosures of which are incorporated herein by reference.

' j Base :14 of the circuit breaker case is provided with a pair ofelectrical terminals 20 and 22 in a manner more fully described below.Base 14 is otherwise made of plastic and is formedwith fourintegral projections 24, one on each side of the base.Housing 16 is similarly moldedof plastic and includesanupper boss 26 and acollar 28 from which depends the hollowrectangular body 30 which forms the major portion of the circuit breaker casing and which houses the operating mechanism of the electromagnetic circuit breaker.Body 30 is provided with four smallrectangular apertures 32 located to receive thebase projections 24 when thebase 14 andhousing 16 are snapped together.

Received in the top ofhousing 16 is amanual actuator 18 of generally U-shaped cros section. The actuator comprises a pair ofsymmetrical handles 34 and 36 forming a rocker and from which depend a pair of spacedlegs 38 and 40. Each of these legs is similarly bifurcated to provideslots 42 which receive a toggle actuator bar 44 (FIG. 3) carried by atoggle link 46. Each of the spacedlegs 38 and 40 is also provided on its external surface with a L-shapedgroove 48 adapted to slidably receive a corresponding one of the nubs "orprojections 50 and 52 projecting inwardly from theboss 26. The inner end of each groove at 54 forms a semicylindrical bearing such that the actuator pivots with the end of each groove engaging one of thenubs 50 and 52. If desired, a small light source, as indicated by thebulb 58, may be secured to a small plastic shelf (not shown) supported by the breaker frame between thelegs 38 and 40 to illuminate thehandle portions 34 and 36 of the actuator. Finally,body 16 is preferably provided with a pair of integralflexible wings 60 and 62, preferably having roughened or serrated end surfaces 64 to provide a snap-in mounting as more fully described below.

During assembly, theactuator 18 is first moved in the direction of thearrow 66 in FIG. 1 so that thenubs 50 and 52 are received in the L-shapedgrooves 48 and 50 formed in the outer surfaces of theactuator legs 38 and 40. The actuator is inserted and then rotated into the position illustrated in FIG. 2 with the semicylindrical bearings rotating about the semicylindrically shapednubs 50. The operating mechanism of the breaker (not shown) is then inserted into thehousing 12 so that theactuator bar 44 is received in theslots 42 in the actuator. With the bar received in the actuator leg slots, the actuator is securely retained or restrained by the operating mechanism ofthe circuit breaker and namely thebar 44 so that it cannot be removed. By depressing first handle 34 and then handle 36 in FIG.2, the actuator is rocked back and forth'about the pivot axis'form'ed by thenubs 50 andactuator bar 44 is correspondingly rocked back and forth to open and close the circuit breaker contacts. Finally,base 14 is moved upwardly in the direction of thearrow 68 in FIG. 1 where it is telescopically received within the lower end ofbody 30 until theprojections 24 snap into theapertures 32 tightly locking the circuit breaker and case assembly together. Once the elements l4, l6, and 18 in FIG. 1 have been assembled, they cannot be readily disengaged without destroying the circuit breaker case.

FIG. 4 shows a snap-in mounting provided by thewings 60 and 62. The circuit breaker is shown mounted on acircuit breaker panel 70 having arectangular aperture 72.Aperture 72 is slightly larger than thebody 30 of the case but is smaller than thecollar 28. The circuit breaker is inserted throughaperture 72 and theflexible wings 60 and 62 compress and pass through the aperture. The circuit breaker is inserteduntilthe collar 28 engagescircuit breaker panel 70, at which time theresilient wings 60 and 62 flex outwardly so that their roughenedsurfaces 64 engage the rear edge of theaperture 72, tightly holding and locking the circuit breaker to the panel.

FIG. shows a flush mounting construction in which acircuit breaker panel 72 is apertured to receive a pair ofscrews 74 and 76. These screws are threaded into the longer leg of a pair of L-shapedbrackets 78 and 80, the shorter legs engaging the back of thepanel 72 and the longer legs are clamped by thescrews 74 and 76 against the underside of thecollar 28. Again, the flexibility of thewings 60 and 62 permit insertion of thebrackets 78 and 80 beneathcollar 28.

FIG. 6 shows a multipole circuit breaker constructed in accordance with the present invention. The'circuit breaker is provided with asingle rocker actuator 18, in all respects identical to the actuator previously described. In FIG. 6, the circuit breaker is a multipole breaker and the housing 16' is provided with six instead of-four apertures, two of which are illustrated at 84 inv FIG. 6, which receivecorresponding projections on the base 14'. Except for the size and number of interlocking projections and apertures, the case illustrated in FIG. 6 is identical to that previously described. The respective poles of the circuit breaker mechanism are interconnected by suitably extendingactuator bar 44 so that it is common to the two toggle links, i.e., one for each pole, corresponding to thetoggle link 46 in FIG.

FIG. 7 is a plan view of a modified -base similar to the base 14 previously described but provided with aplug 92 andauxiliary terminals 94 and 96 for an auxiliary switch. The auxiliary switch adapted to be mounted inplug 92 is omitted for the sake of clarity but may be of conventional construction, as shown byway of example only in assignees U.S. Pat. No. 3,501,606, which is incorporated herein by reference. Also shown in FIG. 7 are the two spacedlegs 98 and I00 of ametal frame 102 on which the operating mechanism of the circuit breaker is mounted.Base 90 is provided with astationary contact 104 adapted tobe" engaged by the movable contact of the circuit breaker mechanism and thisstationary contact 104 is electrically connected in a conventional manner toterminal 22. The other main terminal 20' is adapted to be connected to the'overcurrent coil 'of the mechanism in a conventional manner. Each of these terminals, such as thetenninal 20, is stamped from flat electrically conductive metal stock and is provided with lateral extensions approximately midway of its ends which are slotted so that when the terminal has been inserted throughasuitable aperture in thebase 90, these slotted tabs integral with the terminals are turned over as at 106 and 108 to tightlylock the terminal in position so that it extends from the interior of the base outwardly for connection'to an external circuit to be protected.Plug 92 is removable and-is inserted into a suitable aperture which remains whena knock-out portion of thebase 90 is removed. Theplug 92 fits in the aperture 1 l0 and is provided with a flange at its upper edge as illustrated at 112 which extends outwardly to overlie the adjacent surface ofbase 90.Plug 92 is inserted intoaperture 112 with the flange overlying the base and the-flange 112 is heldin place by the legs and 98 of the'frame which rest on top of theflange 112 as illustrated in FIG. 9.Terminals 94 and 96 may be formed with turned-over portions on each side of theplug in the manner of theterminals 20 or22 or, alternatively, terminals 94.and 96 may be provided with lateral extensions or shoulders 114. andl 16, as illustrated in FIG. 9, on the outer side of the plug. The inner ends are turned over as illustrated at 118 and 120 in FIG. 8. j I

It is apparent from the above that the present invention provides an improved electromagnetic circuitbreaker and in particular an improved circuit breaker case which greatly increases the ease and economy of assembly of the circuit breaker. Through the utilization of plastic materials exhibiting a limited amount of resilience, it is possible to snap the base into the circuit breaker housing and through the provision of flats onnubs 50 the actuator may be attached to the case without any need for rivets, adhesives, epoxy, or the like. The plastic materials make possible a wide variety of colors wherein each of theelements 14, 16, and 18 is of either thesame or different colors to provide different color combinations. in the preferred embodiment, the circuit breaker case is made of all thermoplastic materials and, by way of example only, thehousing 16 andactuator 18 may be molded from a polycarbonate, identified as Lexan 141, manufactured by the General Electric Company. This provides a strong material which is available in a variety of colors. By way of example only, thebase 14 and thecorresponding bases 14' and 90 are preferably formed from a high temperature distortion plastic such as polysulfone, identified as Pl700 as manufactured by Union Carbide Corporation. It is understood that other plastic materials may be utilized where desired but the above'provide excep} tional color characteristics in the polycarbonate in combination with a base material that has a higher temperature distortion point in the electrical contact area.

By providing a snap-in actuator 'l 18 with the spaced legs, it is possible to mount an incandescent orneon bulb 58 between the moving legs of the actuator handle. This provide full handle illumination without bulb movement and the associated problems of wire flexing. While theplug 92 has been described in conjunction with the use of an auxiliary switch, it is understood that the plug may be used in any situation in which two additional terminals are required. The plug is retained solely by the bottom of the circuit breaker base and theframe 102. The terminals are held into the circuit breaker base by the tabs illustrated which are folded over after terminal insertion.

Theactuator 18 is inserted intohousing 16 with thenubs 50 passing through the L-shapedslot 48 to the slot ends 54. This insertion is made possible by providing a small flat 122 on each of the otherwisecylindrical nubs 50 and 52 so that they may be readily inserted into the ends of thegrooves 48. After the actuator has been lowered and rotated into the operating position illustrated in FIG. 2,'it is locked into thehousing 16 by re- J therefore intended to be .embraced therein.

ceipt of theactuator bar 44 into theslots 42 and excessive rotational motion of theactuator 18 is prevented by thebar 44 and the operating mechanism of the circuit breaker toggle.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are What is claimed and desired to be'se'cured by Un' States Letters Patent is:

1. In an electromagnetic circuit breaker, a case comprising a thermoplastic housing, a thermoplastic base, resilient fastening means on said base and said housing joining them together, a toggle bar in said case, and a rocker actuator pivoted to said housing, said actuator having inner ends engaging said toggle bar, said base being provided with a pair of main terminals and an aperture between. said terminals,a nd a plug extending throughsaid aperture and having a flange overlying the inner surface of said base.

2. A circuit breaker according to claim 1 including a frame in said case, said plug flange being clamped between said frame and the interior surface-of said base.

3. In an electromagnetic circuit breaker, a case comprising a thermoplastic housing, a thermoplastic base,

' a resilient fastening means on said base and housing joining them together, a toggle bar in said case, a rocker actuator pivoted to said housing, said actuator having its inner end engaging said toggle bar, said actuator comprising a pair of handle portions joined to a pair of spaced legs, the ends of said legs having slots receiving said toggle'bar, and including a pair of projections on said housing, said actuator including L-shaped grooves slidably receiving said projections.

4. A circuit breaker according toclaim 3 wherei said projections are semicylindrical with flats on one side.

-5. Acircuit breaker according toclaim 3 wherein said grooves have first portions extending from said housing projections toward said slots, and second per-. pendicular portions terminating at a side edge of said legs.

Claims (5)

1. In an electromagnetic circuit breaker, a case comprising a thermoplastic housing, a thermoplastic base, resilient fastening means on said base and said housing joining them together, a toggle bar in said case, and a rocker actuator pivoted to said housing, said actuator having inner ends engaging said toggle bar, said base being provided with a pair of main terminals and an aperture between said terminals, and a plug extending through said aperture and having a flange overlying the inner surface of said base.

2. A circuit breaker according to claim 1 including a frame in said case, said plug flange being clamped between said frame and the interior surface of said base.

3. In an electromagnetic circuit breaker, a case comprising a thermoplastic housing, a thermoplastic base, a resilient fastening means on said base and housing joining them together, a toggle bar in said case, a rocker actuator pivoted to said housing, said actuator having its inner end engaging said toggle bar, said actuator comprising a pair of handle portions joined to a pair of spaced legs, the ends of said legs having slots receiving said toggle bar, and including a pair of projections on said housing, said actuator including L-shaped grooves slidably receiving said projections.

4. A circuit breaker according to claim 3 wherein said projections are semicylindrical with flats on one side.

5. A circuit breaker according to claim 3 wherein said grooves have first portions extending fRom said housing projections toward said slots, and second perpendicular portions terminating at a side edge of said legs.

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