US1780684A

US1780684A - Circuit-interrupting device

Info

Publication number: US1780684A
Application number: US251987A
Authority: US
Inventors: Joseph W Owens
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1928-02-04
Filing date: 1928-02-04
Publication date: 1930-11-04
Anticipated expiration: 1947-11-04
Also published as: GB305480A

Description

Nov. 4, 1930. J, W, WENS 1,780,684

CIRCUIT INTERRUPTING DEVICE Filed Feb. 4, 1928 Inventor Joseph W. Owens,

His Attorneg.

Patented Nov. 4, 1930 JOSEPH W. OWENS, 0F SCHENECTAIDY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK CIRCUIT-INTERRUPT'ING DEVICE Applicationfiled February 4, 1928. Serial No. 251,987.

This invention relates to circuit interrupting devices and more particularly to a detachable arc barrier arrangement for multi pole electric switches and the like.

The principal object of the present inven tion is to provide an improved mounting for the arc barriers that will enable the barriers to be mounted and demounted without the use of tools. In this way the barriers may be easily removed to permit access to the arcing contacts of the circuit interrupter for wiring or inspection and repair.

The improved arc barriers of the present invention are particularly advantageous in multipole electric switches which are mounted within an inclosing casing. With such switches it is desirable that the arc barriers located between the adj acent. poles of the switch be readily removable without necessitating the removal of the switch mechanism from the inclosing casing. Heretofore it has been the common practice to secure the arc barriersto the base upon which the switch contacts are mounted bymeans of screws or other fastenings accessible only from the back of the base. I-Ience with such mounting of the arc barriers it is necessary to unwire and remove the entire switch mechanism from the inclosing casing before the arc barriers may be removed. Moreover, the arc barriers must be secured in place before the switch mechanism is mounted in the inclosing casing and thus prevent free and convenient access to the switch contacts during wiring or inspection and repair operations. In addition the metallic screw fastenings for the arc barriers tend to weaken the insulating properties and cause the arc to strike through the barriers.

The present invention enables the arc barriers to be readily mounted between the adjacent poles of the switch after the base with the switch mechanism thereon is mounted within the inclosing casing and the wiring operation is entirely completed. Likewise, the arc barriers may be readily removed and replaced at any time it is necessary to repair or inspect the switch parts. In addition, with the present invention the arc barriers may be moulded of arc-resisting material, such for example, as an asbestos compound, having a unitary structure provided with locking projections whereby the arc barriers are mounted or supported in their operative position between the poles of the switch mechanism without any metallic fastenings whatever.

In carrying the present invention into effect in a preferred form the arc barriers are formed preferably of moulded arc-resisting material and provided with projecting locking keys adapted to cooperate with suitable locking holes in the base upon which the switch mechanism is mounted. The arrangement is such that the locking keys upon the arc barriers may be inserted in the locking holes formed in the base and the barrier moved laterally with respect to the base to bring the keys into locking engagement with the keyholes. Upon reverse lateral movement of the arc barriers the locking engagement is released to permit removal of the arc barriers. In addition, the arc barriers preferably have formed integral therewith projecting shoulders or shields which serve to cover the looking holes formed in the base and thereby effectively block the passage of the are through the holes formed in the base.

In the accompanying drawing Fig. 1 shows a three-pole electric switch mounted in an inclosing casing and provided with the im proved form of arc barriers, one of the barriers being removed and certain parts of the switch mechanism and casing being broken away to reveal the details of construction. Figs. 2 and 3 are front and reverse perspective views of the unitary moulded arc barrier showing the detailed form of the locking keys and the shoulders formed thereon.

As shown in Fig. 1, the three-pole switch is of the improved type described and claimed in the copending patent application of Louis J. Weber, Serial No. 241,950, filed December 22, 1927, and assigned to the assignee of my present invention, patented December 31, 1929, No. 1,742,109. The three-pole switch mechanism is mounted upon the base 10 which, in turn, is mounted within the inclosing casing 11. Each pole of the three-pole switch mechanism consists of a set of spaced apartstationary contacts 12 which are mounted directly upon the base 10 and a cooperating bridging contact 13 which is yieldingly mounted upon a movable switch arm 14. The three movable switch arms are fixedly secured to an operating member 15 which is rotatably supported in the bearings 16 and 17 In order to prevent arcing between the adj acent poles of the switch, provision is made for mounting an arc barrier 20 on the base 10 between the adjacent sets of stationary contacts 12. The are barriers 20 are formed of good arc-resisting material such as, for example, moulded asbestos compound, and are of suitable dimensions to eiiectively is0 late the arcs occurring at the adjacent poles of the switch.

In accordance with the present invention, each of the are barriers 20 is arranged to be removably mounted on the base 10 of the switch mechanism so as to be readily removable from the front of the panel without the use of tools. This is accomplished by providing a pair of keyhole shaped openings 21 and 22 in the base 10 for each arc barrier. The are barriers in turn are provided on one side with a pair of projecting

locking keys

23 and 24 adapted to be received in and interlocked with the openings 21 and 22. As more clearly shown in Figs. 2 and 3, the

locking keys

23 and 24 have projections 25 on either side so as to interlock with the narrow portions 26 of the key-hole shaped openings 21 and 22. The projections 25, however, are of suitable dimensions to pass through the enlarged portion 27 of the key-hole shaped openings in the base.

It will be evident that after passing the shoulders 25 through the enlarged portion of the key-hole openings, the barrier may be slid downward to bring the projections 25 into interlocking engagement with the narrow portions of the openings and thereby firmly secure each of the arc barriers in operative position on the base 10 between the poles of the switch. In order to insure that the arc barriers are not accidently displaced from the interlocked position by extraneous vibration or during handling of the switch a spring 28 preferably is located at one side of the key-hole shaped openings in the base 10 so as to frictionally engage with the locking key on the arc barrier. It will be observed in Fig. 1 that the upper key-hole shaped openings 22 in the base 10 are not closed at the top. It will be evident, however, that in case the base 10 were extended the key-hole shaped openings 22 would be of substantially the same shape as the openngs 21, except for the provision of the looking spring 28, the mounting of which requires a narrow slot 29 extending from the narrow portion of the opening 22.

In order to prevent the are passing through the enlarged portions of the locking open- 1ngs in the base 10 when the arc barriers are mounted in operative position,

suitable meaese shoulders

30 and 31 are provided on either side of the barrier 20 of suflicient width to cover completely all the openings in the base. The shoulder 31 extends across the full width of the arc barrier so as to cover the slot 29, as well as the right hand edge of the enlarged portion of openings 21 and 22. The shoulder 30 serves to cover the left hand edge ofthe enlar ed opening 21.

With the ase 10 mounted within the inclosing casing 11 and the arc barrier 20 in operative position between thepoles of the switch mechanism as indicated in Fig. 1, the arc barriers may be readily removed by sliding the barrier bodily upward until the interlocking shoulders 25 are moved out of engagement with the narrow portion of the keyhole openings. Thereupon the barrier 20 may be freely withdrawn out of engagement with the base 10. To replace the barrier it is only necessary to reverse the operations just described.

Thus it will be seen that the present inventionprovides an arc barrier construction that permits the barriers to be mounted and demounted at will and without the use of any tools. In addition, the barriers being formed as a unitary structure of arc resisting material without any metallic fastenings required for their support, there is full insulation between theadj acent poles of the switch which efiectively isolates the arcs appearing at each of the poles.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. In a circuit interrupter, the combination of a base having arcing contacts mounted thereon and having key-hole-shaped openings formed therein and an arc barrier having projecting keys operable into and out of interlocking engagement with the open-' ings in the base'upon predetermined relative movement of the barrier with respect to said base.

2. In a circuit interrupter, the combination of a base having arcing contacts mounted thereon and having key-hole-shaped openings formed therein and an arc barrier having projecting keys operable into and out of interlocking engagement with the openings in the base upon predetermined relative movement of the barrier with respect to said base and having shoulders for covering the enlarged portions of the key-hole shaped openings in the base when the barrier is mounted in operative position.

3. In a circuit interrupter, the combination of a base having arcing contacts mounted thereon and having key-hole shaped openings formed therein, an arc barrier having projecting keys operable into and out of interlocking engagement with the openings in the base upon predetermined relative movement of the barrier with respect to said base, and a resilient locking member for maintaining the arc barrier in interlocked engagement with the base.

4. A multipole electric switch comprising a base having a plurality of switch contacts in spaced alignment thereon and having keyhole-shaped openings formed in the base between said contacts, a plurality of arc barriers for mounting in said openings, said barriers each having projecting keys formed on one edge thereof and operable into and out of interlocking engagement with the openings in the base upon predetermined relative movement of the barrier with respect to said base and having shoulders for covering the corresponding openings in the base when the barrier is mounted in operative position.

In witness whereof, I have hereunto set my hand this 3rd day of February, 1928.

JOSEPH W. UWENS.