US2172143A - Circuit interrupter - Google Patents

Description

Sept. 1939. G. N. LEMMON 2,172,143

CIRCUIT INTERRUPTER Original Filed Nov. 9, 1936 Patentedl Sept. 5, 1939 UNITED STATES PATENT OFFICE CIRCUIT INTERRUPTER mingham, Ala.

Application November Renewed 9 Claims.

This invention relates to the type of circuit interrupter known as an expulsion fuse, in which a usible link is placed inside an insulating tube which is open to the atmosphere at one or both ends, and which upon overload interrupts the circuit by the fusing of the link and the sudden expulsive effect of the resultant arc inside the tube. It also relates to similar circuit interrupters in which the circuit is opened inside the tube by manual or electromagnetic means, instead of by thermal means.

Referring to the drawing, Fig. 1 shows a general view of an assembled unit embodying this invention; Figs. 2, 3 and 4 show in large scale details of the top latch in different positions; and Fig. 5 shows in perspective another position of these same parts.

The insulators I, are supported by any suitable hanger 2, and in turn they support the forked bearing 3 and top fitting 4.

The latch hood 5 is pivoted at B and its travel in both directions is limited by the stop 1 on. the fitting 4.

'I'he tube 8 carries two trunnions 9 which are held by 3 and about which the tube pivots. 'Ihe swing end of the tube carries the fitting I to which is pivoted the link II which in turn pivotally supports the latch I2. A fuse link I3 within the tube 8 completes the circuit between the line I4 and line I5. The screw I6 secures one end of the fuse link, and the screw I'I together with the plate I8 hold the button head I9 which is at .the other end of the link I3. Tension on the link I3 prevents rotation of the latch I2 about its double pivot at II.

When the tube is being closed in, the upper tip `of the latch I2 engages with the tooth 5', thereby slightly rotating the hooded latch 5 about its pivot 6. The member I2 also pushes back the brush 24, and then 5 drops down aided by the spring 26, so that the projection 5 engages and holds I2 in closed position as shown in Fig. 1. When upon overload the fuse ruptures and tension on I2 is released, the latch I2 disengages from the tooth 5', andthe tube 8 falls by gravity to the position shown by dotted lines in Fig. 1.

On such equipment a low-amperage fuse-link is often used, and it is desirable to prevent excessive strain upon this small link at all times. It is also advisable to protect moving joints from sleet which otherwise might prevent proper operation. The hood 5 has an internal pivotal mounting at 6 and the lower flared edges of 5 tend to divert rain or sleet away from the parts beneath. Also the latch I2 has an internal pivotal 9, 1936, Serial No. 109,958 July 15, 1939 (Cl. G-116) mounting at I I, and thus further protection is given to this double-pivoted joint.

The wide end 20 of the latch I2 serves as a shield to keep rain out of the top opening of the tube 8, and further protection is given by the iiange ZI on the tting I9, and by the projecting end 23 of the tube 8. The liange 22 nts between 2| and 23 and gives additional protection against rain. When the fuse link has ruptured from overload, hot gases are expelled upward from the tube 8, and the interlocking arrangement of flanges retards hot gases from the tube from eX- panding towards the insulators, while allowing relatively free expansion away from the insulators. Since these hot gases are conductive, this is desirable.

The iianges also allow a slight transverse motion of the double pivot at II. If .the fused tube when put into service is slammed hard against the brush 24 and its stop 25, the parts assume the positions shown in Fig. 2, with the flange 22 'bearing against the tube end 23, and taking the force of the blow away from the fuse link.

Then if the tube 8 is pulled or bounces outwardly, the motion of I I allows the other side of the flange 22 to be pressed against the flange 2|, as shown in Fig. 3.

These members are usually castings, and their surfaces are slightly rough, due to the sand mold. When the flanges are pressed together there is considerable friction due to this roughness, and the rotation of the latch I2 about its pivots at I I is thereby definitely retarded. This reduces the strain which is imposed on the link I3 under given conditions. Another factor in the reduction of strain on the link I3 is the fact that the tube 8 can move in or out somewhat while the latch I2 remains still; this softens the hammerblow action of the tube 8. With a single pivot I2 any counter-clockwise rotative strain on latch I2 would be borne entirely by the fuse link I3, with no diminution due to friction, and with all momentum of the tube 8 being applied to cause rotation of the latch I2.

Furthermore, when the fuse link I3 has been ruptured, as by overload, a very slight rotative motion of I2 allows the iiange 22 to clear the flange 2 I, as in Fig. 4. Then as the tube 8 moves outwardly, the link I I can drop downward with the latch I2, and so release the latch from 5', allowing the tube 8 to drop fully open.

There are various modications which can be made from the details as here described without departing from the purpose and spirit of this invention.

projects, a latch member movably I claim:

1. In a circuit interruptor, in combination, two insulated supports, a tubular container pivotally mounted upon one of said supports, a fusible conductor within the container, and a Contact member connected to the swing end of ane container by a double-pivotal mounting, and a second contact member supported by the second insulated support and engageable with the said rst Contact member.

2. InV a circuit interrupter, two gap-spaced insulated terminals, an insulating tube with a ilexible conductor therein movable into and out of circuit closing position between the said two terminals, a contact member to engage with one of said terminals and to hold the tube in closed-circuit position, said contact member being connected tothe tube by a double jointed pivotal mounting.

3. In a circuit interrupter, two gap-spaced insulated terminals, an insulating tube with a iiexible conductor therein movable into and out of circuit closing position between the said two terminals, a Contact member to engage with on'e of said terminals and to hold the tube in closed-circuit position, said contact being connected to the tube by a movable link and two pivots.

4. In a circuit interrupter, two gap-spaced insulated terminals, an insulating tube with a flein'ble conductor therein movable into and out of circuit-closing position between the said two terminals, a metallic fitting near the upper end. of the said tube from which the end of the tube attac-hed to the said fitting, said latch member and said f1tting including interlocking barriers to modify the discharge of gases from the'end of the tube.

5. In a circuit interrupter, two gap-spaced insulated terminals, an insulating tube with a iiexible conductor therein completing the circuit across the said gap, one end of said tube being open for the discharge of gases, a movable cap adjacent the said open end of the tube, together with barriers adjacent the said cap and interlocked to retard the flow of any gas past the barriers.

6. In a circuit interrupter, two gap-spaced insulated terminals, an insulating tube with a flexible conductor therein completing the circuit across the said gap, one end of said tube being open for the discharge of gases, a movable cap adjacent the said end of the tube, together with means stationary with the tube and adjacent to the cap to direct the discharge of gases away, from the said insulated terminals.

7. In a circuit interrupter, two gap-spaced insulated terminals, an insulating tube with a flexible conductor therein completing the circuit across the said gap, one end of said tube being open for the discharge of gases, a movable cap adjacent the said open end of the tube, together with a barrier stationary with the tube and a coordinated barrier on the cap, operable to modify the discharge of gases from the said tube.

8. In a circuit interrupter, a pivotally mounted tubular container, a fusible conductor within the container, a contact member mounted on the container by a double pivoted hinge, said contact member being also a protective shield for its own pivotal mounting.

9. In a circuit interrupter, two gap-spaced insulated terminals, an insulating tube with a flexibleV conductor therein movable into and out of circuit closing position between the said two terminals, a metallic fitting near the upperend of the said tube, a latch member movably attaohed to the said tting and forming a protectiver shield forV the end of the tube, Vsaid latch member and said ttin'g including coordinated means to modify the discharge of gases from the tube.

G. N. LEMMON.

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