US2735911A

US2735911A - Circuit interrupter

Info

Publication number: US2735911A
Authority: US
Publication date: 1956-02-21
Anticipated expiration: 1973-02-21

Description

Feb. 21, 1956 R. P. SANT CIRCUIT INTEIRRUPTER 2 Sheets-Sheet 1 Filed April 6, 1955 INVENTOR. h 5a Feb. 21, 1956 s NT 2,735,911

CIRCUIT INTERRUPTER Filed April 6, 1955 2 Sheets-Sheet 2 INVENTOR.

United States Patent CIRCUIT INTERRUPTER Ralph P. Sant, South Milwaukee, Wis., assignor to McGraw Electric Company, Milwaukee, Wrs., a corporation of Delaware Application April 6, 1953, Serial No. 347,044

2 Claims. c1.200-117 This invention relates to a fuse construction and in particular to a throw out attachment for a mechanical fuse link breaker.

There are frequent occasions when it is desirable to open a fuse cutout manually either to inspect the cutout or to sectionalize some electrical equipment that the cutout protects. Numerous cutouts have been designed for this purpose, one notable design being the one disclosed in U. S. Patent 2,3l0,466, issued to William O. Schultz and Alwin G. Steinmayer and assigned to the same assignee as this application. There are other fuse cutouts with manual means for opening them under small loads. However, these are not operable with loads of 75 to 100 amperes. The action is not fast or strong enough to disconnect the cable effectively.

A manual opening device must operate with mechanical decisiveness so that no failure is involved. A stumbling action would incur a faltering response. With electrical circuits, if the break is not quick and complete, arcing will result which can be very destructive or even disastrous.

The object of this invention is to provide a means for making a clean swift break of the fuse link in any kind of Weather condition.

Another object of this invention is to prevent arcing by positioning the lever of the fuse breaking means a distance from the upper terminal and to move it even farther away from the upper terminal with the fuse breaking movement.

A further object of this invention is to combine a flip out device with the lever of the fuse breaking means, to accelerate the movement of the leader out of the fuse tube.

And another object of this invention is to provide a fuse breaking device that will apply maximum force in expelling the leader from the fuse tube.

Other objects will appear from time to time in the course of the specification and claims.

This invention is designed to provide a novel form of fuse construction in which the automotive functioning of the fuse under overload is preserved and at the same time means are provided whereby the circuit may be manually opened under load and to so construct the device that the arc is confined within the fuse tube whether the fuse is severed automatically or manually and so that the expulsive action in either case is employed to quickly extinguish the arc and permit interruption of the circuit with perfect safety.

I illustrate my invention in the accompanying drawings in Which:

Fig. 1 is a side elevation with parts broken away, of a fuse cutout incorporating my fuse break lever.

Fig. 2 is a sectional view of the fuse break lever in closed position.

Fig. 3 is a sectional view of the fuse break lever in open position.

Like reference characters indicate like parts throughout.

Referring to Fig. 1, I illustrate my fuse break lever 1 incorporated in the lower portion of a mechanical fuse cutout 2. The fuse cutout 2 is mounted upon opposite ends of an insulator 3, the center part of which is supported by means of the clamp 4 or any suitable member from any desired support. Or if desired, the upper and lower stationary contacts can be carried by separate insulators. The upper contact comprises a housing 5 which is provided with a suitable connector 6 by means of which a line wire may be attached, and this housing 5 is equipped with a spring pressed latch 7 which normally fits over the tip or pin 8 of the removable cap 9 of a fuse tube 10. The fuse tube is an expulsion type fuse tube and is open at the lower end. The lower end of the tube 10 is provided with a downwardly extending arm 11. The arm 11 is provided with a collar portion 12 which is securely attached to the fuse tube. The downwardly extending arm 11 has an expanded skirt portion 13 provided with trunnions 14 on the outer sides thereof which fit within hook shaped brackets or supports 15 of the lower contract 16. The lower stationary contact 16 is provided with a connector 19. The upper and lower contacts are secured to the upper and lower ends of the insulator 3 in any suitable manner as by means of the clamping brackets illustrated.

The upper end of the fuse tube may be provided with an eyelet 20 which is pivoted at 21 and provided with rearwardly projecting arms 22 adapted to lift the spring pressed latch 7 when it is desired to manually rock the fuse tube outwardly. Preferably an upper contact spring provided with a pair of arms 23 is provided, the contact arms 23 bearing downwardly on the cap 9 and the contact arms 23 and the latch 7 having upwardly turned cam portions to facilitate the rocking of the fuse back into position after having been refused.

The fuse tube 10 is made of a fibre material and has a conductor cable with a fusible portion extending longitudinally through it, then through the fuse break lever 1 and to the outer side of the fuse tube where it is secured to the fuse tube by a knurled nut on the opposite side from the side shown in Fig. 1. Figs. 2 and 3 show an enlarged section of the lower end of the fuse tube and cable in relationship with my fuse break device.

The fuse break device 1 pivots at 24 on the expanded skirt 13 of the arm 12. At the opposite end from the pivot point 24 is an eyelet 25 by means of which a hook stick can be applied to open the fuse break lever to the position shown in Fig. 3. Within the fuse break lever and pivotally attached thereto at 26 is a fiip out arm 27. This flip out arm 27 is spring biased so that when the fuse link is severed within the fuse tube either from overload or upon opening the fuse break lever, an extra thrust action is applied to remove the fuse coil from the fuse tube.

The interior of the fuse break lever 1 is formed with channels to contain and hold the conductor cable 28. The cable 28 is threaded between a wall 29 and the flip out lever 27 and around a finger 30 extending angularly downward within the fuse break lever 1.

The use and operation of my invention are as follows:

The cable extending through the fuse tube has a fusible section which dissolves upon overload. This fusible section is also slightly weaker and can be severed when a pull is exerted upon it. This pull is transmitted to the weak spot by a lever action on the cable. The end of the cable emerging from the fuse tube is threaded through the lever 1 and around the flip out arm 27 while it is in the closed or in upward position as shown in Fig. 2. When it is desired to break the fuse link in order to open the cutout under load, the lever 1 is pulled downwardly to the position of Fig. 3. This downward thrust breaks the fuse link within the fuse tube and as soon as the fuse link is severed the flip out arm 27 under spring pressure is released to spring downwardly and thus it quickly removes the free end of the cable from the fuse tube. It is this quick action of the flip out arm in unison with the breaking action on the fuse that prevents dangerous arcing or faulty load break. This manual means of opening a cutout during load is sturdy enough to be used when amperages in the vicinity of 100 are flowing through the cutout. The lever will not bend and the severing and removal action is sufficiently decisive to prevent destruction or disaster.

I claim:

1. A fuse cutout including in combination spaced-apart line terminals, an insulating fuse tube having an open end, a fuse link in said tube comprising a fusible element and a conducting leader and normally electrically connecting said line terminals, clamping means on said fuse tube intermediate the ends thereof arranged for retaining the leader end of said fuse link, and a manually operable link-break lever pivotally mounted on one of said terminals adjacent the open end of said fuse tube and having a manipulating means spaced laterally outwardly from said tube, said lever being apertured to receive a looped portion of said leader and including a flip out arm pivotally mounted thereon and engageable with said leader, said arm being biased for outward rotational movement relative to said lever and away from said open end of said fuse tube.

2. A fuse cutout including in combination spaced-apart line terminals, an insulating fuse tube having an open end, a fuse link in said tube comprising a fusible element and a conducting leader and normally electrically connecting said line terminals, clamping means on said fuse tube intermediate the ends thereof arranged for retaining the leader end of said fuse link, and a manually operable link-break lever pivotally mounted on one of said terminals adjacent the open end of said fuse tube and having a manipulating eyelet spaced laterally outwardly from said tube, said lever being apertured and including a transverse integral web for dividing said aperture into two chambers for receiving a looped portion of said leader, and a flip out arm pivotally mounted on said lever and engageable with said leader, said arm being biased for outward rotational movement relative to said lever and away from said open end of said fuse tube.

References Cited in the file of this patent UNITED STATES PATENTS 1,998,042 Boothe Apr. 16, 1935 2,154,688 Matthews et al Apr. 18, 1939 2,269,135 Tate Ian. 6, 1942 2,310,466 Schultz et a1 Feb. 9, 1943 2,323,213 Garrison June 29, 1943 2,324,044 Triplett et a1 July 13, 1943 2,409,077 Steinrnayer Oct; 8, 1946 2,460,967 Amundsen Feb. 8, 1949 2,637,795 Hubbard May 5, 1953 FOREIGN PATENTS 30,630 Australia Apr. 23, 1931