US1763384A - Circuit breaker - Google Patents

Description

June 10, 1930. c, ANDERSON in AL CIRCUIT BREAKER 3 Sheets-Sheet 1 Filed July 24, 1925 INVENTORS CHEL ER/c fi/vDcWrso W1; 1. gm H. KEFE, Jr:

ATTORNEYS June 10, 1930.

C. E. ANDERSON ET AL I CIRCUIT BREAKER Filed Ju ly 24, 1925 5 Sheets-Sheet 5 INVENTORS CHRL [PIC finlozasanl WILL/4M Ker/ 5, /sM; MM

ATTORNEYS Patented June 10, 1930 UNITED STATES PATENT oar-ice can we ANDERSON, OI STRA TFORD, AND WILLIAM 8. WE, JD, BBIDGEPORT, NINECTICUT, ABSIGNOBS TO THE BRYANT ELECTRIC COMPANY, OF BBIDGEPOBT, oommcncu'r, A CORPORATION OF CONNECTICUT CBCUIT 133mm Application ma m a4, 1925. Serial mum Our invention relates to circuit breakers, and particularl to a thermostatically controlled circuit reaker. Among the special objects of our invention may be mentionedfirst, a self-contained circuit breaker, the

mechanism of which is contained within a sealed housing, together with exposed means for establishing electrical connection with the fixed contacts within the housin sec- 0nd, a sealed circuit breaker adapted for detachable mounting in a panel board installation; third, the combination of a sealed circuit breaker and a panel board fitting adapted for the reception of the sealed circuit breaker; fourth, an automatic circuit breaker mechanism adapted to be manually operated by a rotary spindle; fifth, a rotar operating handle adapted to serve as an in icator both on manual operation and on thermostatic operation of the circuit breaker; sixth, certain details of construction hereinafter described or shown in the accompanying drawings, in

whieh- Fi 1 is a plan view of a pair of juxtaposed pane board fittings with which the resent circuit breaker is associated, the pane cover being removed from one of the units;

Fig. 2 is a plan view drawn to a larger scale of portion of a panel board unit with the panel cover and circuit breaker casing removed;

Figs. 3 and 4 are sections on the lines 3 -3 and 44, Fig. 2, respectively;

Fig. 5 1s a plan view corresponding to Fig. 2 but showing the mechanism in the position assumed on automatic opening of the circuit; and

Fig. 6 is a more or less diagrammatic plan view of a panel installation of different type, to which the present circuit breaker is applied.

In the construction shown in Figs. 1-5 we have shown a combined panel board fitting and automatic circuit breaker, the latter in detachable form and sealed to revent tampering with the mechanism. T e sealing of the circuit breaker unit we regard as of importance since it prevents unauthorized attem ts to regulate the automatic operation of e mechanism.

The panel board fitting comprises an insulating panel block 15 of a generally rectangular form, transversely channelled at 16 and 17 ad acent one end for the reception of feed mains 18 and 19. Branch circuit ter minals 20 and 21 are arranged at the opposite end of the block 15, the terminal 21 being electrically connected to the main 19 by the shunt strap 22 let into the lower face of the block. A short shunt 23 leads from the branch terminal 20 to a point beneath a bay 24 opening to a well 25 formed in the upper face of the block intermediate the branch terminals 20 and 21 and the feed mains 18 and 19. A second short shunt 26 extends from the main 18 to a point beneath a second bay 27, also opening to the well 25. The circuit breaker is arranged in the well 25 and electrically interposed between the shunts 23 and 26.

While the well 25 may be of any appropriate shape we have indicated a circular well to correspond to the shape of the insulating base 28 of the circuit breaker. A fixed contact 29 on the upper face of the base 28 is connected by a screw 30 to a terminal plate 31 let into the-lower face of the base 28 and projectin beyond the margin of the latter to enter t e bay 2-1 opening to the well 25. A screw 32 serves to connect the terminal strap 31 with the shunt 23 connected to the branch terminal 20 on the panel board block 15. A second fixed contact 33 mounted on the base is electrically connected in a manner hereinafter described, with a bracket 34 (Fig. 4) which in turn is connected by a screw 35 with a terminal strap 36 which extends beyond the base 28 and is so located as to enter the bay 27 A screw 37 passing through the panel block 15 establishes electrical connection with the shunt 26 leading to the main 18.

The circuit breaker mechanism mounted on the upper face of the base 28 is housed in by a cover 38 provided with an insulating lining 39 and havin aosuitable opening in its to through whih projects a spindle 40 by w ich the mechanism may be manually operated. Engaging the flatted spindle 40 is an actuating' t umb piece 41 which is secured upon the spindle by a screw 42, the head of which is accommodated in a depression 43 in the outer end of the thumb piece. Sealing material 44 covers the head of screw 42 and thus prevents access thereto. The cover 38 which encases the circuit breaker mechanism, and which rests upon the annular ledge 45 of the base 28, is held in osition by the thumb piece 41. Inasmuc as the latter is sealed on the spindle 40, the circuit breaker mechanism is permanently enclosed and inaccessible until the seal 44 is broken and affords a telltale indication that the mechanism may have been tampered with.

It will be clear from the foregoing that the circuit breaker unit is self-contained and may be assembled upon the panel block 15 by merely dropping it in the well 25 and establishing electrical connection with the shunts 23 and 26 by turning down the screws 32 and 37. The projecting terminal straps 31 and 36 insure the proper positioning of the circuit breaker unit on t e base, since they are so located that the latter can be dropped in the well in only one position.

The conductors on the panel base 15 are protected by a panel board unit cover 46 provided with an insulating lining 47 and attached to the panel block 15 by means of thumb screws 48 and 49 located at its opposite ends. Inasmuch as the circuit breaker cover 38 projects above the level of the block 15, against which the panel'cover 46 rests, the latter is provided with a central opening 50 through which the circuit breaker cover 38 projects. It will be clear that in order to remove the circuit breaker from the panel block 15, it is necessary to first lift the panel block cover 46 in order to obtain access to the screws 32 and 37, which serve not only to establish electrical connection through the breaker, but also to mechanically secure the latter upon the panel block.

The circuit breaker mechanism bears a general resemblance to that shown in our copending application Ser; No. 39,312, filed June 24, 1925, but adapted in certain particulars to the manual operation of the mechanism by a rotary spindle. It will suffice for the disclosure of our present invention to point out that the current passin through the circuit breaker from the terminal strap 36 to the terminal strap 31 follows a course through the branches 51 and 52 of a U- shaped thermostatic element, the branch 51 being connected to the bracket 34, and the branch 52 to a bridge strap 53, thence through screw 54, shunt 55 and screw 56 to the fixed contact 33. The movable circuit closer 57 bridges contact 33 and contact 29 in circuit-closing position, and the ath of the current follows the screw 30 an terminal strap 31 connected by screw 32 and shunt 23 to the branch terminal 20.

The circuit closer 57 is mounted in the free end of a rock lever 58, the opposite end of which is ivoted at the bottom of the opening of the -frame 59. This frame in turn is pivoted at 60 in the fixed bracket 61, and is detained by a lug 62 which rests u on the shoulder 63 of a pivoted latch 64 w en the parts are in their normal position.

Cooperating with the lever 58 is an oscillating yoke 65 pivoted at 66 on the fixed bracket 61 and having a limited throw within the arcuate recess 660 in the base in which one side of the yoke plays. An operatin spring 67 extends between the yoke 65 an rock lever 58 to cause the rock lever to shift to open or closed circuit position in well understood manner upon the shifting of the end of the yoke 65 across the point of support of the lever 58. The actuation of the yoke is effected through the thumb iece 41 and spindle 42, the latter being rigi 1y connected to the yoke.

The latch 64 is ivoted at 68 and its free end is engaged wit the catch 69 suitably secured through insulation at the free end of the thermostatic element. So long as the current does not become excessive the latch 64 remains in the position shown in Fig. 2 and the frame 59 is maintained in such position that the yoke 65 travels its full throw on the throw of the rock lever 58 to open and closed circuit positions.

If, however, the current becomes excessive and the thermostatic element is warped out of its normal position, the catch 69 is withdrawn from the nose of the latch 64 and the latter swings to the position shown in Fig. 5 under the pressure of the frame lug 62 a ainst the shoulder 63 of the latch, eventual y escaping the latter and shifting its position under the pull of the spring 67, until halted by the stop pin 7 0. The swing of the frame 59 not only positively throws the lever 58 to open-circuit position, but also shifts its pivot point across the plane of effort of the spring 67, with the result that the yoke 65 tends to move across its arc. It is halted in mid-position, however, by the lug 71 on the frame 59. Inasmuch as the thumb piece 41 oscillates with the spindle 40, it occupies, when the circuit breaker is thus thermostaticall operated, a mid-position between the off and on legends 72 and 73, which mid-position may be indicated by an independent legend 74 with which the pointed end of the thumb piece now registers.

To return the parts to normal position the yoke -65 is swun to off circuit position, shifting with it the frame 59 which is halted by sto pin 70. As it moves in this direction, the yo e 65 bearing against the lug 71, swings the frame 59 until its lug 62 engages the nose 75 of the latch 64, and swin s the latter on its pivot 68 until its free en displaces and passes the catch 69 on the thermostatic element, so that upon release of the rating handle 41 the latch 64 re-engages t e catch 69 under the efiort of the sprin 67. Itwill be apparent from the foregoin t at while the a mechanism in general resemb es in function that of our copending application, we have made certain changes in detail which adapt it for operation by a rotary spindle, and for accommodation upon a base to which the spindie is substantially normal.

To indicate that our invention is not confined in its utility to a panel board unit of the ty e shown in Figs. 1-5, we have illustrated in Fig. 6 a diflerent type of panel comprising feed bus bars 80 and 81 with branch usses 82 and 83. The circuit breaker is supported and electrically interposed between the us bars 83 and 80 b means of the terminal straps 31 and 36. he advantages of the sealed-in mechanism are maintained in an installation of this character.

Various modifications in details by which our objects may be accomplished, w1ll readily occur to those dealing with the problem,

without departing from what we claim as our invention.

We claim- 1. In a circuit breaker, a connection block having conductors thereon, a detachable cover overlying said conductors, said cover being apertured, in combination with a circuit breaker unit adapted to pass through the aperture in said cover and being detachably mountable on said block, said unit having laterally projecting terminals overlaid by the connection block cover.

2. Electrical apparatus comprising an insulating connection block recessed to receive the base of a circuit breaker unit, spaced bays in said block opening to said recess,and conductors secured to said block and including contacts in said bays, together with a circuit breaker unit comprising an insulating base, mechanism on said base, a housing held to 5 said base and covering said mechanism, and terminals extending from said mechanism and laterally beyond said base and cover, said terminals being adapted to lie in said bays when said base is in said recess and to be connected to said contacts, whereby said circuit breaker ma be connected to said block without remova of its housing.

In testimony whereof we have signed our names to this specification.

CARL ERIC ANDERSON.

WILLIAM H. KEEFE, JR.

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