US2091802A - Circuit interrupter - Google Patents

Description

1937. T. BIRKENMAIER ET AL 2,091,802

CIRCUIT INTERRUPTER Filed Sept. 25, 1935 Patented Aug. 31, 1937 UNITED STATES PATENT OFFICE Mosley,

Richmond Heights, Mo., assignors to The W. N. Matthews Corporation, St. Louis, Mo., a corporation oi Missouri Application September 23, 1935, Serial No. 41,650

11 Claims.

This invention relates to circuit interrupters, and with regard to certain more specific features, to an interrupter responsive to thermostatic action.

Among the several objects of the invention may be noted the provision of an improvement upon the construction shown in the United States Patent 2,025,525 of Ralph R. Pittman and Carroll H. Walsh, filed August 6, 1934, dated December 24, 1935, for Circuit interrupter; the provision of apparatus of the class described which may be simply applied by screwing a plug into a socket and pressing a cap with longitudinal movement only; the provision of apparatus of the class described which shall open the circuit upon overload and which shall not be immediately reclosable; the provision of a device of the class described in which, if it be reclosed in an overloaded circuit, will promptly interrupt said circuit; and the provision of apparatus of this class which is more compact in form and simpler to operate. Other objects will be in part obvious and in part Pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing, in which are illustrated two of various possible embodiments of the invention,

Fig. 1 is a side elevation showing one form of the invention;

Fig. 2 is a vertical section taken on line 2-2 of Fig. l, the device being shown in open-circuit position;

Fig. 3 is a view similar to Fig. 2 showing the device in closed-circuit position;

Fig. 4 is a vertical section taken on line 4-4 of Fig. 3;

Fig. 5 is a cross section taken on line 55 of Fig. 2;

Fig. 6 is a cross section taken on line 6-6 of Fig. 3;

Fig. '1 is a cross section taken on line 1-1 of Fig. 3; and,

Fig. 8 is a fragmentary view similar to the one shown in Fig. 3, but showing an alternative embodiment of the invention.

Similar reference characters indicate corresponding parts throughout the several-views of the drawing.

Referring now more particularly to Fig. 1, there is shown at numeral I a cylindric, metallic, current-conducting body having round threads 3 for application to the usual electric socket. The body I forms a first contact.

Held in the bottom of the body I is 9. diaphragm 5 of di-electric material which holds a central, second contact 1.

Attached to the inside of the body I by means of a force fit is a metallic guide bushing 9 providing an annular recess II for a coil spring I3, the latter reacting from the bottom of said recess II against a flange I5 of a metallic slide I1. Parts 9 and I1 are both conductors.

The slide I1 slidably bears on the bushing 9 at its lower end and is flanged outwardly at I5 to slidably bear at I 9 on the body I. The body I carries a fixed pin 2| which, at its inner end is engaged by a groove 23 formed in the enlarged portion III of said slide I1, thus preventing relative rotation of slide I1 and body I.

The slide I1 carries a bi-metaliic thermostat 25 of inverted U-shape, one leg of which is held to the slide I1 by a fasteher 21, the latter being insulated from said slide I1. The fastener 21 ,also holds a third, U-shaped, spring contact 29. The other leg of the thermostat 25 is electrically connected at 3| with said slide I 1. By pressing the slide I1 downwardly the third contact 29 engages the second contact 1 as shown in Fig. 3.

The upper end of the U-shaped thermostat 25 is free and has fastened thereto a latch pin 33, notched as shown at 35 to normally engage one side of an opening 31 in a metallic washer 39 held fast in an insulating cap 4i, the latter being arranged slidably on the outside of the body I. The cap 4| carries a groove 43 which cooperates with the outside end of said fixed pin 2| to prevent relative rotation between said cap 4| and body I but to permit reciprocation thereof on the body. A pin 45 in the lower end of the groove 43 prevents the cap M from being entirely removed from the body I.

The slide I1 is limited in its upward travel by means of a ring 41 forced into the upper end of the body I. The ring 41 carries a flange 49 (which, however, may be omitted) and at its lower end effects a flange 5| with respect to the inside cylindric form of the body I.

Springs 50 normally force the cap H in a direction to contact the pin 45 with pin 2|,

and thus normally to place the lower edge of the washer 39 above the notch 35 in the latch 33 in the upper position of the latter.

The cap 4I pivotally carries a latch 53 which is pressed by means of spring 55 to a position to catch either the flange 49 (when used) or the flange i depending upon the elevation of the cap 4! from the bottom of the device.

The thermostat 25 has a normal cold position shown by solid lines in Fig. 4 and a hot position 5 shown by the dotted lines in that same figure. The cold position is the one which is effective during normal current flow, and the hot position is the one which clears during abnormal current flow, the material and cross-section of the thermostat being calculated to produce this effect in view of the current flowing.

Starting with the device as shown in Figure 2 which is its open-circuit position, it maybe screwed into a socket and then the cap ii pushed down to the position shown in Fig. 3. Inasmuch as the latch pin 33 at this stage has its notch 35 in the solid-line position shown in Figs. 4 and 6, the washer 39 will contact the notch and force the thermostat 25 downwardly, thus carrying along the slide ll against the reaction of spring l3. Finally, the latch 53 catches under the flange 5| to hold the parts in the position shown in Fig. 3, wherein the contact 29 is in electrical engagement with the contact l. Current then flows through the contacts I and 29, fastener 21, through the thermostat 25, slide l1, bushing 9, body I, and to the line. Under normal conditions of current flow, the solid-line position of thelatch pin 33, as shown in Fig. 4, will be maintained. I

Upon overload, the thermostat 25, having been chosen for proper value of resistance to bring about the effect, deflects to the dotted-line position shown in Figure 4. This immediately clears the notch 35 from the washer 39 (dotted lines of Fig. 4, and Fig. 5) and the slide I] under the influence of the spring l3 jumps from the position shown in Figs. 3 and 4 to the position shown in Fig. 2. This causes the upper end H of the 40 slide I! to contact the sloping face 56 of the latch 53, thus moving the latch from its caught position on the flange 5|. This releases the cap 8| which, under the influence of springs 50, move from the position shown in Fig. 3, to that shown in Fig. 2.

If the user then attempts immediately to push back the cap 4|, to reclose the circuit, he will not meet with success because the thermostat 25 takes some time to cool and before doing so,

maintains its deflected, dottedline position. Thus the pin 33 freely pames through the hole 31 (Fig. 5). The time taken for cooling is usually enough to clear the line of trouble and if it is not, a resetting will again result in deflection of the thermostat and a subsequentrelease with consequent re-opening of the circuit.

In Fig. 8 is a modified form of the invention in which like numerals designate like parts. In this form, a shunt resistance 51 is held by the fas- 30 tener 21 and is placed in electrical contact with the slide I! by means of a second fastener 59. The purpose of this resistance is to function as a calibrating means for the thermostat 25. Thus, with one design of structure such as shown in 5 Figs. 1 to 7, various overload conditions may be met by varying the resistance 51. At the time of manufacture, the proper valueof resistance 57 is determined, the same depending upon the conditions of operation of the fuse.

70 The latch 53 is provided with a finger El with which cooperates a stem 63 of a button 65. The stem and the button are slidable in the cap 4! and the stem 63 is held prisoner by a pin 61 in the cap which intersects a notch 69 in said pin 63.

75 By manually pressing the button 65 the latch 53 may be removed from the flange 5!, thus to cause the slide i! to be forced to open-circuit position. The strength of spring 55 is such that the release can be effected without requiring a force at the button 65 great enough to prevent the spring l3 from expanding.

In view of the above, it will be seen that the several objects of the invention are achieved, and other advantageous results attained.

As many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained in .the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. A circuit interrupter comprising a contact body member, a second contact attached thereto but electrically separated therefrom, a slider in the body member normally biased away from said second contact, a latch-holding means on said body, a reciprocating cap on said body, a latch in said cap cooperable with said latch-holding means, a deflecting thermostat mounted on said slider and electrically connected thereto exclusively at one end, a third contact electrically connected to the thermostat at its other end movable into and out of engagement with said second contact upon reciprocation of the slider, a latch controlled by deflection of said thermostat, means on the cap cooperating with said latch in the cold position of the thermostat to permit forcing of the slider to a position where the third and second contacts electrically engage, said latch on the head being held on said latch-holding means on the body, said slider being adapted to subsequently release said latch on the head from its latch-holding means upon deflection of the thermostat.

2. In a circuit interrupter, a cylindric body, forming an electrical contact, a second contact fastened to said body but electrically separated therefrom, a; third contact, a hollow slider in said body normally biased away from said second contact, a U-shaped thermostat supported in the hollow slider and open downwardly, one leg of which is electrically connected to the slider and the other of which is insulated therefrom, said last-named leg having electrically connected thereto said third contact, a reciprocating head on said body, a latch movable by deflection of said thermostat, latch-engaging means on said head adapted to engage the latch in the cold position of the thermostat and to disengage therefrom in the hot position of said thermostat, and a second latching means on said head adapted to hold the same against the bias of said slider and to be pushed toward said second contact while the thermostat is cold, means for releasing the said last-named latch by said slider when said thermostat deflects to release the first-named latch, and biasing means normally pressing the cap away from said second-named contact.

3. A circuit interrupter comprising a cylindric conducting body threaded to thread into a threaded socket, a second, central insulated contact associated with said body, a conducting slider in said body, a spring contact mounted on and beneath said slider and springingly cooperable with said second contact upon reciprocation of the slider, a U-shaped thermostat within the slider positioned withits open side downwardly, one leg of said thermostat being insulated from the slider and attached to said spring contact, the

other leg being electrically connected with the slider, a reciprocating head on the body, latching means between said thermostat and said head adapted to effect movement of the slider from said head when the thermostat is cold and another latch on the head adapted to hold the same against the bias of the slider in the cold position of the thermostat.

4. A circuit interrupter comprising a cylindric conducting body threaded to enter a threaded socket, a central insulated contact associated with said body, a conducting slider in said body, a spring contact mounted on said slider and cooperable with said second contact upon reciprocation of the slider, a U-shaped thermostat within the slider positioned with its open side downwardly, one leg of said thermostat being insulated from the slider and attached to said spring contact, the other leg being electrically connected with the slider, a reciprocating head on the body,

latching means between said thermostat and said head adapted to effect movement of the slider from said head through the thermostat when the latter is cold, and another latch on the head adapted to hold the same down against the bias of the slider in the cold position of the thermostat, said first-named latching means between the thermostat and the head in the hot position of the thermostat releasing to permit biasing movement of the slider, said slider and said secondnamed latch means being cooperable to release the head after said movement of the slider.

5. A circuit interrupter comprising a cylindric conducting body threaded to enter a threaded socket, a central insulated contact associated with said body, a conducting slider in said body, a spring contact mounted on said slider and cooperable with said second contact upon reciprocation of the slider, a U-shaped thermostat within the slider positioned with its open side downwardly, one leg of said thermostat being insulated from the slider and attached to said spring contact, the other leg being electrically connected with the slider, a reciprocating head on the body, latching means between said thermostat and said head adapted to effect movement of the slider from said head through the thermostat when the latter is cold, and another latch on the head adapted to hold the same down against the bias of the slider in the cold position of the thermostat, said first-named latching means between the thermostat and the head in the hot position of the thermostat releasing to permit biasing movement of the slider, said slider and said secondnamed latch means being cooperable to release the head after said movement of the slider, and means biasing said head in the direction of the bias of said slider.

6. A circuit interrupter comprising a body forming one contact, a second contact insulated therefrom but mounted thereon, a biased slider therein, a third contact on said slider, a deflecting thermostat mounted on said slider, a reciprocating head on said body, latch means between the thermostat and the head, and means for holding the head against the bias of the slider upon movement of the same when the thermostatically controlled latch is in cold position, said latch opening to release the slider to assume its bias in the hot 70 position of the thermostat, said slider cooperating with the means holding the head to release the same.

'I. A circuit interrupter comprising a body forming one contact, a second contact insulated 75 therefrom but mounted thereon, a biased slider therein, a third contact on said slider, a deflecting thermostat mounted on said slider, a reciprocating head on said body biased in a direction away from said slider, a first latch means between the thermostat and the head, a second latch means between the head and body for holding the head against the bias of the slider upon movement 01' the head against bias of the slider when the thermostatically controlled latch is in cold position, said flrst'latch opening to release the slider to assume its bias in the hot position of the thermostat, said slider cooperating with the second. latch means to release the head.

8. A circuit interrupter comprising axially movable contact members for opening and closing of circuit, a thermostat carried by one of said members, biasing means opposing the engagement of said contact members, a movable cap for urging said contact members to closed circuit position, a latch normally holding the cap against said biasing means, said thermostat cooperating with the cap for normally maintaining the interrupter in closed circuit position when said latch normally holds the cap against the action of said biasing means, said thermostat carrying current and adapted upon overload to heat itself and to disengage from said cap for permitting the switch to assume an open circuit position.

9. A circuit interrupter comprising axially movable contact members for opening and closing of circuit, a thermostat carried by one of said members, biasing means opposing the engagement of said contact members, a movable cap for urging said contact members to closed circuit position, a latch normally holding the cap against said biasing means, said thermostat cooperating with the cap for normally maintaining the interrupter in closed circuit position when said latch normally holds the cap against the action of said biasing means, said thermostat carrying current and adapted upon overload to heat itself and to disengage from said cap for permitting the switch to assume an open circuit position, and separate biasing means for biasing the cap to a position wherein the thermostat may again cooperate therewith when the switch is open, said latch being adapted to be opened when the switch assumes open-circuit position so that said last-named biasing means may operate on the cap.

10. A circuit interrupter comprising axially movable contact members for opening and closing of circuit, a thermostat carried by one of said members, biasing means opposing the engagement of said contact members, a movable cap for urging said contact members to closed circuit position, a latch normally holding the cap against said biasing means, said thermostat cooperating with the cap for normally maintaining the interrupter in closed circuit position when said latch normally holds the cap against the action of said biasing means, said thermostat carrying current and adapted upon overload to heat itself and to disengage from said cap for permitting the switch to assume an open circuit position, a separate biasing means for biasing the cap to a position wherein the thermostat "may again cooperate therewith when the switch is open, said latch being adapted to be opened when the switch assumes open-circuit position so that said lastnamed biasing means may operate on the cap, cooperation between the thermostat and cap for closing the switch being adapted to take place thereatter only when the thermostat is in a cold position, said cap and its latch being freely reciprocable and unadapted to force or hold the switch in closed-circuit position.

11. A circuit interrupter comprising axially movable contact means for opening and closing a circuit, a thermostat carried by one of said members and forming a driving link whereby said members may be driven to closed-circuit position, biasing means opposing the engagement of said contact members, a movable cap for urging said contact members to closed-circuit position, a latch normally holding the cap against said biasing means when the contacts are closed, said thermostat in its cold P sition cooperating with the cap for normally maintaining the interrupter in closed-circuit position while said latch normally holds, and said thermostat carrying current for heating itself whereby upon overload it will disengage from said cap for permitting the switch to assume an open-circuit position, the separation of the contact members eflecting opening of said latch, and means whereby said cap is then driven to a position to be engaged by said thermostat'for reclosing said contact members by movement of said cap it and when said thermostat assumes a cold position.

THEODORE BIRKENMAIER. CARL E. MOSLEY.

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