US2548617A - Circuit breaker - Google Patents

Description

April 19, 1951 PURPURA 2,548,617

CIRCUIT BREAKER Filed Aug. 18, 1948 2 Sheets-Sheet 1 awe/14M L. FUR/ UR April 10, 1951 PURPURA CIRCUIT BREAKER 2 Sheets-Sheet 2 Filed Aug. 18, 1948 3 m 1. PUP/ 064 Patented Apr. 10, 1951 UNITED STATES PATENT OFFICE This invention relates to circuit breakers.

An object of this invention is to provide in a switch connected to a three phase motor or other electrical appliance using three supply wires, an automatically operable circuit breaker adapted to move the switch to circuit breaking position when an overload on any one line or wire blows the fuse connected with such line so that the motor or appliance will not burn out.

Another object of this invention is to provide in a circuit breaker of this kind an improved operator for the main switch which is normally de-energized, but is energized upon blowing of any one of the fuses, and will develop sufficient initial power or force so as to throw the main switch to circuit breaking position and at the same time break the circuit to the operator.

A further object of this invention is to provide a circuit breaker for a three phase motor embodying a solenoid operator for the main switch and a switch in each of the three lines connected to the operator with the latter switches springpressed to circuit closing position but held in open or circuit breaking position by the fuses in the three lines, blowing of any one fuse releasing the associated switch for movement to circuit closing position to thereby energize the operator and throw the main switch to open or circuit breaking position.

To the foregoing objects, and others which may hereinafter more fully appear, the invention consists of the novel construction, combination and arrangement of parts, as will be more specifically referred to and illustrated in the accompanying drawings, but it is to be understood that changes, variations, and modifications may be resorted to which fall within the scope of the invention a claimed.

In the drawings, 7

Figure 1 is a plan view of a circuit breaker constructed according to an embodiment of this invention;

Figure 2 is a sectional view taken on line 2-2 of Figure 1;

Figure 3 is a fragmentary sectional view taken on line 33 of Figure 1;

Figure 4 is a fragmentary end elevation taken substantially on the line 4-4 of Figure 1;

Figure 5 is a longitudinal section through the solenoid;

Figure 6 is a diagrammatic view showing the electric circuits embodied in this invention.

Referring to the drawings, the numeral IE3 designates generally a base which may be formed of insulating or other suitable material and the base has mounted thereon three spring-pressed main line switches designated generally I 1, I2 and I3. The switches II, I2 and I3 are of like construction and each includes a stationary contact H which is secured to an upstanding support carried by the base It. Each main line switch also includes a movable contact it which is carried by a lever arm or blade I! rockably carried by an upstanding mounting G8 which is secured to a rearwardly projecting base member it formed integral with the support 55. The support [8 has a terminal [9 onthe upper end thereof with which is adapted to be connected a supply conductor. The rear end of the lever arm 5'? has pressing on the lower side thereof an expanding spring 29 which engages at its lower end a case member 2! and the spring 259 is adapted to constantly urge the lever 11 to a circuit closing position.

There is a fuse 22 for each main line switch and one end of the fuse 22 is clamped to a fuse holder 23 electrically connected with the stationary contact I4 and the other end of the switch 22 is clamped by means of a clamping plate 24 to a terminal member 25. The terminal member 25 is adapted to be connected to one side of a three phase motor M as shown in Figure 6. The fuse 22 includes reduced frangible portions 255 adjacent the holders or clamping members 23 and 2s and also includes an intermediate reduced thickness frangible portion 2'1.

In order to provide for automatic movement of the main line switches I I, I2 and I3 when any one of the fuses 22 blows, I have provided a cam shaft 28 which is mounted on upstanding bearings 29 carried by the base It). The cam shaft 28 has secured thereto a plurality of cam members 30, there being one cam member for each contact lever IT and each cam member 30 has disposed thereabout an insulating sleeve 3| which is adapted to engage the lower side of the lever arm I! as shown in Figure 2. One end of the cam shaft I8 has fixed thereto a manually operable lever 32 and the other end of the cam shaft 28 has fixed thereto an arm 33 as shown in Figure 4.

The shaft 28 also has fixed thereto a circular plate 34 having a pin 35 on the outer side thereof with which a spring 36 is connected at one end. The spring 36 at the other or lower end is fixed relative to the base In and the sprin 36 is adapted to hold the cam shaft in either circuit breaking or circuit closing position.

A solenoid generally designated as 31 is fixed by fastening means 38 to the base Iii and the solenoid 31 as shown in Figure 5 includes a shell 39 having end plugs 48 and 4| in the opposite ends thereof. The fastening members 38 are threaded into the end plugs 48 and 4!. The shell 39 has disposed therein three electrically connected together solenoid coils 52, 48 and 44. The

coils 42, 43 and 44 are connected together in parallel being spaced apart within the shell 39 and there is slidably mounted within the coils iron cores 45, 46 and 41.

The cores 45, 46 and 41 are connected together by non-magnetic means 48 and 49 and the core 41 is adapted to strike a headed non-magnetic pin 50 slidable in the forward end plug 41. The pin 50 is disposed in a position to engage the arm 33 as shown in Figure 4 so that when the solenoid coils 42, 43 and 44 are energized the pin 50 will be moved forwardly and outwardly and will strike the arm 33 so as to rock this arm clockwise as viewed in Figure 4 thereby partially rotating cam shaft 28 and raising contact carrier arms I! to circuit breaking position.

The coils of solenoid 31 are energized by means of spring-pressed switches generally designated as 52 which are spring-pressed to circuit closing position. An insulated switch housing 53 is disposed between the main line witches ll, I2 and I3 and the terminals 25, and the housing 53 has mounted therein three solenoid switches 52. The switches 52 include a common contact bar 54 and a spring-pressed movable switch member 55 normally urged to circuit closing position. The three movable switch arms 55 are connected together by means of a common connecting bar or conductor 56 and each switch arm 55 is held in circuit breaking position by means of a rod or wire 51 which'is secured at its lower end to the switch arm 55 and has secured to the upper end thereof an insulating hook member 58.

The insulating hook member 58 engages over the intermediate fuse portion 21 and when the fuses 22 are normal, the holder comprising the wire or rod 57 and the hook 58 will hold the switch arm 55 in circuit breaking position. However, when any portion of a fuse 52 blows or burns that fuse will be bent downwardly by pressure of the associated spring-pressed switch arm 55 so that a circuit will be completed to the solenoid 31.

The conductor or common contact bar 55 is connected by means of a conductor 59 to one of the terminals of the main line switches and in the present instance is connected to terminal 23a associated with main line switch II. The connector or conductor 56 is connected by means of a conductor 68 to one side of the solenoid 37 and the other side of the solenoid 3'1 is connected by conductor 8! to terminal or fuse holder 23.

In the use and operation of this circuit breaker, the main line switches ll, 12 and 13 are connected to the supply source and the three terminals 25 are connected to the terminals of three phase motor M. In the normal operating position of this structure lever arm 33 will be disposed in the full line position shown in Figure 4 and cam shaft '28 will be disposed as shown in Figure 2 with movable contact 18 engaging stationary contact I4.

The several solenoid operating switches 52 will be held in circuit opening position by the holders comprising the wire or rod 51 and the hook 58. In this manner solenoid 3'! will be normally inactive or de-energized. In the event there is an overload causing any one of the fuses 22 to break or blow, the associated solenoid switch 52 will be released for movement to circuit closing position by release of the switch arm holder l58. Solenoid 31 will thereby be energized and pin 50 will be moved outwardly striking arm 33 a sufficient blow to swing this arm downwardly and forwardly so that pin 35 will move past the vertical center of cam shaft 28 whereby spring 36 will swing cam shaft 28 an additional distance permitted 4 by means of stop 62 disposed in the path of the swinging of arm 33.

At this time the three switch arms l'l'will be raised to circuit breaking position and at the same time the circuit to the solenoid 31 will be broken.

I claim:

In a circuit breaker having a base formed of insulating material, a fixed contact carried by said base, an upstanding mount disposed from said fixed contact and insulated therefrom, a rockable lever carried by said mount having a movable contact engageable with said fixed contact, said lever having an extended end extending outwardly from said mount and disposed opposite said movable contact, spring means engaging said extended end constantly urging said contacts together, a rotatable shaft carried by said base and disposed under said rockable lever, a cam rotatably carried by the shaft for engagement with said lever on rotation of said shaft to rock the contacts apart, a circular plate carried by said shaft for rotation therewith, said plate having an over center spring means for biasing said cam to and from cammed engagement with said rockable lever, an arm having one end secured to said shaft with an opposite end free for movement, a trip means having a solenoid adapted to be connected in circuit with said fixed contact for energization on a change in the circuit characteristics, said solenoid having an armature confronting said arm for engagement with said opposite end to rotate the shaft from a cam free to a cam engaged position on energization of the solenoid.

LIBORIO PURPURA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 825,333 Morganthaler July 10, 1906 1,012,599 Clemens Dec. 26-, 1911 1,063,179 Burnham June 3, 1913 1,231,992 Blumberg July 3, 1917 1,288,820 Braunwarth Dec. 24, 1918 1,309,027 Gilliett July 8, 1919 1,380,168 Whittingham I -1 May31, 1921 1,692,138 Orr Nov. 20,1928 1,760,814 Case May 27, 1930 1,780,612 Anderson Nov. 4, 1930 1,904,141 Hurlburt Apr. 18, 1933 1,964,018 Wurdack June 26, 1934 2,000,899 Durdin, Jr. May 14, 1935 2,027,238 Lindstrom Jan, 7, 1936 2,076,849 Kennedy Apr. 13, 1937 2,170,412 Jennings Aug. 22, 1939 2,306,585 Appelberg Dec. 29, 1942 FOREIGN PATENTS Number Country Date 579 Great Britain Jan. 8, 1912 288,372 Germany Get. 29, 1915 326,768 Great Britain Mar. 17, 1930 555,328 Great Britain Aug. 17, 1943 626,416 France May 9, 1927 OTHER REFERENCES Electrical Review, Apr. 4, 1947.

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