US2060481A

US2060481A - Electric switch

Info

Publication number: US2060481A
Application number: US720611A
Authority: US
Inventors: Bascum O Austin
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1934-04-14
Filing date: 1934-04-14
Publication date: 1936-11-10
Anticipated expiration: 1953-11-10

Description

B. O. AUSTIN ELECTRIC SWITCH Nov. 10, 1936.

Filed April 14, 1934 A INVENTOR MCI/f)? Qiuf/n.

, WWI. 01W

Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE ELECTRIC SWITCH Pennsylvania Application April 14, 1934, Serial No. 720,611

'2 Claims.

My invention relates, generally, to electric switches, and more particularly to switches of the electro-magnetic type wherein the contact members are actuated by electro-magnets.

An object of my invention, generally stated, is to provide an electric switch which shall be simple and efllcient in operation and which may be economically manufactured and installed.

A more specific object of my invention is to increase the speed of operation of an automatic electric switch under overload or short-circuit conditions.

Another object of my invention is to provide a quick acting overload trip mechanism for an electric switch.

Other objects of my invention will be either explained fully hereinafter or will be apparent to those skilled in the art.

In accordance with one embodiment of my invention, the moving contact arm of a switch is operated. by the over-load trip mechanism with out moving the main armature of the switch, thereby quickly opening the contact members by actuating the parts of the switch having a minimum weight.

For a fuller understanding of the nature and objects of my invention, reference may be had to the following detailed description taken in conjunction with the accompanying drawing, in which:

Figure 1 is a view, in side elevation of an electro-magnetic switch embodying my invention;

Fig. 2 is a view, in side elevation, of the switch illustrated in Fig. 1 showing the position to which the movable contact member of the switch is actuated by the overload-trip mechanism, and

Fig. 3 is a diagrammatic view illustrating the manner in which the switch may be connected in an electric circuit.

Referring now to the drawing, and particularly to Figs. 1 and 2, the switch which is illustrated comprises a main operating magnet l and an overload-trip magnet ll, both of which are mounted on an insulating base 12. The magnet is provided with an energizing coil l3, a core I 4 and an armature member l5 that is pivotally mounted on the frame l6 of the switch by a pin l1.

As shown, the overload-trip magnet I I comprises a series or operating coil l8 and a holding coil l9, both disposed on one leg of a U-shaped member 2|. The magnet II is provided with an armature member 22, also pivotally mounted at H, which is actuated to the trip position shown in Fig. 2 when a. predetermined value of current flows through the series coil l8. The holding coil l9 will retain the armature 22 in the position shown in Fig. 2 after it has been raised to that position by the series coil l8.

The main armature carries a movable contact member 23 that is disposed to engage a fixed contact member 24 when the armature is actuated to the position shown in Fig. 1 by the operating magnet ID. The contact member 23 is mounted on a contact-carrying arm 25 which is pivotally mounted on the armature l5 by a pin 26. A spring 21 is provided for resiliently pressing the movable contact member 23 against the fixed contact member 24.

In order that the contact members of the switch shall be opened quickly when the current in the overload coil l8 exceeds a predetermined value, the contact-carrying arm 25 is so connected to the downwardly extending arm 3| of the armature 22 by a link 32 that the contact-carrying arm 25 is actuated about its pivot point 26 to open the contact members when the armature 22 is raised to the position shown in Fig. 2. After thecontact members have been partially opened by the overload-trip mechanism in the foregoing manner, the main operating magnet 10 is deenergized and the main armature I5 is permitted to drop to its lowermost position, thereby further opening the contact members of the switch.

In this manner the contact member 23 is disengaged ;from the contact member 24 without moving the main armature I5, thereby providing a means for interrupting the circuit through the contact members by operating the parts of the switch having a minimum weight, which makes it possible to greatly reduce the time required to open the contact members and interrupt the circuit. The opening speed of the switch under overload or short-circuit conditions is fast enough to limit the peak current, thus reducing the damage to other equipment that may be connected in the circuit controlled by the switch.

As shown in Fig. 3, the switch herein described may be utilized as a line switch to connect a propelling motor of an electric vehicle to a trolley conductor 4|, the series coil l8 of the overloadtrip magnet ll being connected in the motor circuit when the

contact members

23 and 24 of the switch are closed. The energizing coil l3 of the operating magnet 10 is energized through a contact segment 42, which may be on the master controller and an interlock member 43 which is actuated by the overload-trip mechanism.

As described hereinbefore, the series coil ill will operate the overload-trip mechanism to partially open the contact members of the switch when the current flowing through the 'coil exceeds a predetermined value. When the overload-trip mechanism is operated by the series coil II, the interlock ll is actuated to interrupt the circuit through the main magnet coil II and to establish a circuit through the holding coil ll, thereby energizing the holding coil to retain the armature 12 in its uppermost position until the controller segment 42 is actuated to reset the overload-trip mechanism, after which the operating magnet coil I! may be energized to reclose the contact members of the switch.

From the foregoing description, it is apparent that I have provided a simple and quick acting overload-trip mechanism which may be readily applied to any switch of a type having a pivoted contact-carrying arm, such as the electro-magnetic switch shown in the drawing or a pneumatically-operated switch oi a type well known in the art.

Since numerous changes may be made in the above-described construction and difierent embodiments of the invention may be made without departing from the spirit and scope thereof, 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.

I claim as my invention:

1. In an electric switch, in combination, a fixed contact member, a movable contact member disposed to engage the fixed contact member, a pivotally-mounted contact arm for supporting the movable contact member, means for actuating the movable contact member into engagement with the fixed contact member, and means (or opening said contact members to an intermediate position between their fully open and fully closed positions independently oi! the last named means.

2. In an electric switch, in combination, a fixed contact member, a movable contact member disposed to engage the fixed contact member, a pivotally-mounted contact arm for supporting the movable contact member, means for actuating the movable contact member into engagement with the fixed contact member, and means for actuating the contact arm about its pivot point to open said contact members to an intermediate position between their fully open and fully closed positions independently of the last named means.

3. In an electric switch, in combination a fixed contact member, a movable contact member disposed to engage the fixed contact member, a pivotally-mounted contact arm for supporting the movable contact member, means for actuating the movable contact member into engagement with the fixed contact member, and. means responsive to a predeterminedvalue of current for actuating the contact arm about its pivot contact member. a movable contact member diaposed to engage the fixed contact member, a pivotally-mounted contact arm for supporting the movable contact member, operating means for actuating the movable contact member into engagement with the fixed contact member, and electro-magnetic means responsive to a predetermined value of current for actuating the contact arm about its pivot point to open said contact members to an intermediate position between their fully open and iully closed positions independently of the operating means.

5. In an electric switch, in combination, a fixed contact member, a movable contact member disposed to engage the fixed contact member, a pivotally-mounted contact arm for supporting the movable contact member, electro-magnetic operating means for actuating the movable contact member into engagement with the fixed contact member, and an overload device responsive to a predetermined value of current for actuating the contact arm about its pivot point to open said contact members to an intermediate position between their fully open and fully closed positions independently of the electro-magnetic operating means.

6. In an ,electric switch, in combination, a fixed contact. member, a movable contact member disposed to engage the fixed contact member, a pivotally-mounted contact arm (or supporting the movable contact member, electro-magnetic operating means for actuating the movable contact member into engagement with the fixed contact member, and an electro-magnetic overload device having an armature member for actuating the contact arm about its pivot point to open said contact members to an intermediate position between their fully open and fully closed positions independently of the electro-magnetie operating means.

7. The combination with an electric switch having a pivotally-mounted contact arm for supporting a movable contact member and operating means for actuating the movable contact member into engagement with a fixed contact member, of an electro-magnet having a pivotallymounted armature disposed to actuate said contact arm about its pivot point to open said contact members to an intermediate position between their fully open and fully closed positions independently of said operating means when the electro-magnet is energized by a predetermined value oi! current.

BASCUM O. AUSTIN.