US2221528A

US2221528A - Electric switch

Info

Publication number: US2221528A
Application number: US208385A
Authority: US
Inventors: Richard H Schmitt
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1938-05-17
Filing date: 1938-05-17
Publication date: 1940-11-12
Anticipated expiration: 1957-11-12

Description

Nov. 12, 1940 R H SCHWTT 2,221,528

ELECTRIC SWITCH Filed May 17, 1938 `J4 da n Inventor: Richard H. Schmitt,

Patented Nov. l2, 1940 UNITED STATES PATENT OFFICE ELECTRIC SWITCH New York Application May 17, 1938, Serial No. 208,385

3 Claims.

This invention relates to electric switches, and more particularly to switches of the quick make and break type.

It is an object of the invention to provide an improved construction andy arrangement in switches of this type having a minimum of parts which may be easily assembled within the switch casing. The construction is reliable in operation and insures a rm and even contact between the l switch circuit-closing members.

In the accompanying drawing, Fig. l is a sectional view through the switch; Fig. 2 is a plan view of the bottom of the switch with the closure cover removed; Fig. 3 is a perspective view of a l portion of the switch-operating mechanism; Fig. 4 is a view substantially along the line 4-4 of Fig. l with the switch housing in section; Fig. 5 is a sectional view along the line 5-5 of Fig. l, and Fig. 6 is a perspective view of a portion of the switch mechanism showing one of the contacts in open and in closed position.

Referring to the drawing, a housing I0, which may be formed of insulating material such as a phenolic condensation product and ller, or

the like, is provided for the switch mechanism.

-The housing is formed at the bottom with a substantially rectangular recess Il for receiving the contact terminals of the switch mechanism, while a cavity I2 extends from the recess toward the top of the housing for receiving the switch-operating handle. In order to provide for mounting of the switch upon a base the housing is formed with diametrically opposed openings I3.

According to the invention pairs of terminal members I4 and I5 are arranged symmetrically within the recess I I and are secured to the housing by means of drive pins I6. Each of the terminal members is provided with a terminal screw Il for connection to the conductors of an elecl, trical circuit. The conductors are led into the body of the switch through the slots I8 which are disposed on opposite ends of the switch housing and which merge with the recess I i. Each of the terminal members II is provided with a projecting contact I9, while the terminal members I5 are provided with similar contacts 2li.

In each case the contacts of each pair of terminal members cooperate with a corresponding shorting roller or contact 2i mounted in a rocker 22. The rocker 22 is formed of insulating material and is mounted in the vhousing by means of opposed bearing elements 23 disposed in grooves 22 formed in the housing, the bearing portions being held in the grooves 24 by means of a pin 25 extending through the housing. The pin 25 rests in grooves 26 formed on each side of the housing so that the rocker 22 is pivotally mounted for oscillatory motion to and fro Within the housing.

The shorting rollers 2i are resiliently or mov- 5 ably mounted upon the rocker 22 in order to make and break contact with the pairs of contact lugs I9 and 2li, respectively. To this end the shorting rollers are disposed in grooves or slots 21 formed in the opposing arms 28 of the rocker. The rolll0 ers are maintained in the grooves by the coiled torsion springs 29 which are nested in slots 30 formed in each ofthe arms 28. The U-shaped end 3I of the coiled torsion springs is disposed within the slot 30 and is retained therein by the 15 pin 32 integral with the rocker, While the opposite prong ends 33 of 4the torsion springs rest in grooves 34 formed on each of the ends of the shorting rollers and serve to maintain the rollers seated Within the slots 21. The torsion springs 20 29 maintain the shorting rollers securely seated Within the slots 2'I at all times.

Upon oscillating the rocker to switch-closing position the shorting rollers make contact with the contact lugs I9 and 20. At this time the rocker continues to move to a position beyond that at which the rollers engage the contact lugs so that the rollers are retained against the contact lugs and move a small distance Within the grooves 2l, as shown by Fig. 6. This relative movement between the rollers and rocker element is permitted by exure of the torsion springs. The springs now are tensioned further to maintain the rollers rmly against the contact lugs. This construction ensures a rm contact between 1 the rollers and contact lugs under the inlluence of the'torsion springs and thus the contact pressure is not one which depends upon the degree of movement of the rocker element upon operating the switch but depends upon the constant force exerted by the torsion springs.

The rocker is provided with an operating handle 35 which projects through an opening 36 formed in the top wall of the housing adjacent the cavity I2. Upon operation of the handle the switch may take either of two positions to close either the right or left-hand` pairs of contacts through the medium of the shorting rollers. In

.mid-position the switch is Oi.v The various positions of the rocker element are determined i by a positioning mechanism comprising a plurality of grooves 31 formed integrally on each side of the body of the rocker element which cooperate with projections 39 formed in the side members 40 of a rectangular spring blade. The spring 40 comprises a flexure plate which is compressed between the positioning grooves 31 and the top wall of the housing. Three of the grooves 31 are provided, the center one designating the OiI position and the two adjacent ones "On positions. As the switch is moved from one position to the other, the spring 40 is exed to permit the projections 39 to enter one of the grooves 31.

The recess Il is closed by a plate 4| of insulating material provided with a centrally disposed upstanding portion 42 which cooperates with a rounded surface 43 on the rocker member to steady it in position. The closure plate is locked to the housing by means of a strap 44 having bent-up ends 45 placed over the projections 46 formed on the outside of the housing.

In connecting up the switch the conductors are inserted through the slots or openings I8 and are connected to the terminal screws l1. As the switch is operated to and fro the circuit across the pairs of contact lugs I9 and 20 is closed by means of the shorting rollers 2|. In some circumstances, it may be desirable to interconnect two of the terminal members and such a connection is shown at 41. When the switch is turned to circuit-closing position the snorting rollers are brought into contact with the pairs of terminal contacts I9 and 20 and are iirmly held against them by the action of the torsion springs 29 which maintain excellent electrical contact between the contacts and the rollers.

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

1. In combination, a housing, spaced contacts mounted on opposite sides of said housing. a rocker element pivotally mounted in said housing for oscillatory movement between said contacts, said rocker element having a groove and a slot therein, a shorting contact comprising a roller member disposed in said groove, spring means mounted in said slot on said rocker element and having prong ends on each side of said element engaging said contact to retain it within said groove, said spring means being flexed upon engagement of said snorting contact with said spaced contacts to permit relative movement between the rocker element and snorting contact whereby said spring means maintains said shorting contact in engagement with said spaced contacts.

2. In a switch structure, a housing having a recess therein, a rocker element pivotally mounted within said recess and having opposed arms, each of said arms being provided with a groove and a slot therein, a roller contact element mounted in each of said grooves, spring means mounted in each of said slots on said rocker element and each -having prong ends disposed on opposite sides of said rocker element for engaging corresponding contact elements and retaining them within said grooves, pairs of contact members mounted in said recess and cooperating with each of said roller contacts, said roller contacts sliding in their respective grooves on engagement with said ilxed contacts under oscillatory vmovement of said rocker element and being held in engagement with said spaced contacts by the prong ends of said spring means.

3. A switch comprising a housing, a rocker element mounted in said housing and having a groove and a slot therein, a roller contact slidably disposed in said groove, spring means mounted in said slot and having prong ends engaging said roller on each side of said rocker element for retaining the contact within said groove, iixed contacts mounted in said housing and disposed on each side of said rocker element for engagement with said roller contact on oscillatory movement of said rocker element, and a exible leaf spring engaging said rocker element and the wall of said housing to position said rocker element in either contact closing or contact opening position.

RICHARD H. SCHMI'I'I.