US1535924A - Electric switch - Google Patents

Description

April 28, 1925. 1,535,924

G. s. LEDDICK ELECTRIC SWITCH Filed July 9, 1924 Inventor": George S. Leddick H s Attorney.

Patented Apr. 28, 1925.

UNITED STATES PATENT OFFICE.

GEORGE S. LEDDICK, 0F SCHENECTADY, NEW YORK, ASSIGN TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC SWITCH.

Application filed July 9, 1924. Serial No. 725,079.

To all whom it may concern:

Be it known that I, Gnonon S. LEDDICK, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Electric Switches, of which the following is a speciiication.

My invention relates to electricswitches and more particularly to electric switches of the type having aplurality of movable contact fingers and a relatively movable bridging member cooperating therewith.

One of the objects of my. invention is to provide an improved switch of the above type in which electrical contact is established bet-ween the several contact fingers and then is broken with one of the fingers and maintained with the other fingers when the movable bridging contact member is operated from one position to a second position and which is provided with means for preventing contact with the said one finger upon the return of the bridging member to the first position. I

Although not necessarily limited thereto my improved electric switch is especially well adapted for controlling an electromagnetic line switch of a. translating device such as for example an electric motor, particu larly where shipper rod operation of the controlling switch is desired. In such application my improved switch takes the place of the usual stop and start push button stations and provides connections for maintaining effective the under voltage protective feature of the line switch mechanism.

For a better understanding of my invention reference is had to the following description taken in connection with the are companying drawing in which Fig. 1 is a perspective View of an electric switch embodying my invention, Fig. 2 is a perspective view showing the relative positions of the several parts of the switch shown in Fig. 2 after operation to the second position, and Fig. 3 is a circuit diagram showing the connections of the switch when employed to control an electromagnetic line switch for a translating device.

' The novel features which I believe to be characteristic of my invention are pointed out with particularity in the appended claims.

Referring to Fig. 1, a switch shaft 10 is rotatably supported in the brackets 11 and 12 which are secured to a base 13 of suitable insulating material. The central portion of shaft 10 is encased in an insulating sheath 1% upon which a bridging contact member 15 is secured by means of the clamps 16 and 17 and the screws 18. A set of contact fingers 19, 20 and 21 which are pivotally mounted in the supporting frames 22, 23 and 2% respectively are disposed in spaced alignment with the end of the contact fingers in the path of different portions of the bridging contact members 15 as shown. Each of the frames 22, 23 and 2a is notched to receive the opposing tongues which extends from the sides of the contact fingers 19, 20 and 21 and the removable keys 25, 26 and 27 and the cooperating compression springs 28, 29 and 30 are provided for maintaining the several contact fingers in engagement with the sup porting frames and also serve to bias the contact fingers to the position shown.

An operating lever 31 is suitably secured to one end of switch shaft 10 and is arranged to be connected to a shipper rod or other reciprocating operating member. A stop 32 is provided for limiting the movement of the rotatable shaft 10 when it is operated from the position shown in Fig. 1, and a. suitable biasing means such as the over center device shown comprising the curve member 33 and the compression spring 3a is provided for biasing the switch shaft 10 to the last position to which it is operator It will be observed that the portion 35 of thebridging contact 15 which cooperates with the contact finger 19 is of shorter length than the portion 36 which cooperates with the contact fingers 20 and 21, due to the fact that a part of the first portion has been cut away. The reverse side of contact iingcr19 is covered with a sheet of suitable insulating material 37 such as hard. fibre or the like which may be riveted to the contact finger as shown.

As thus constructed and arranged the operation of my improved switch mechanism is as follows: lVhen the operating lever 31 is moved to the left from the position shown in Fig. 1 into the position shown in Fig. 2, the bridging contact 15 is carried into overlapping contact with all of the contact fingers 19, 20 and 21 at an intermediate position, thus electrically interconnecting the same. Upon continued movement of the operating lever 31 to the left, the contact fingers 19, 20 and 21 are rotated'from the position shown in Fig. 1 against the bias of the compression springs 28, 29 and 30 respectively and at a second intermediate position the shorter portion 35 of the bridging contact is carried out of engagement with the end of contact finger 19 and the latter at once returns to the initial position to which it is biased by spring 28. The portion to bias the latter to the 36 otthe bridging member 15 however is sufficiently long to maintain engagement with the contact fingers 20 and 21 when the operatinglever 31 is operated to the extreme left hand position as shown in Fig. 2. As the switch is'operated to the position shown in Fig. 2 in the manner just described, the

lower end of the curvedmember 33 is carried over the center of switch shaft 10 and serves position to which it is operated.

Upon the return movement of the operating lever 31 from the positionshown in Fig. 2, the portion 35 of the bridging member '15 I engages with the insulating sheet 37 carried a short interval during, the movement of the latter from the position shown in Fig. 1

I to the position shown in Fig. 2 and that electrical contact with the finger 19 is prevented upon the I return member.

In Fig. 3, my improved switch is shown arranged to operate as a master switch for the electro-magnetic line switch 38 which controls the connection of the electric motor movement of the contact 39 to the supply lines 40. then the bridging contact 15 is operated from the off position in which it is shown to interconnect the contact fingers 19, 20 and 21 as previously described, an energizing circuit for the operating winding of switch 38 is established from the lower of the supply lines 40 through the finger '19, bridging contact 15, finger 20 and the operating winding to the middleoi the supply lines 40. This causes the electromagnetic switch 38 to close and connect the motor 39 to the supplyline 40. At the same time a holding circuit for the operating winding of switch 38 is established through the auxiliary contact 41 with which the switch 38 is finger 21, bridging contact 15and finger 20.

Thus as the movement of bridging contact 15 is continued and contact is'broken with the finger 19, the initial energizing-circuit for switch 38 'is opened andthe switch 38 is maintained energized by a circuit includ ing the auxiliary contact 41. Hence, if the voltage of the supply line 40 decreases below the value required to maintain the switch 38 in the closed position the latteropens and disconnects the motor 39 from the supply line 40. Should the voltage of supply line 40 again become normal, the electromagnetic -SWltCl1 38 can not be closed until the master switch operatinglever 31 is returned to the initial position and manually operated to complete an energizing circuit for switch 38 through the contact finger ,19- as previously described. I I

In accordance with the provisions of the patent statutes .I have described the principles of operation of my invention together with the apparatus which I now consider to represent the bestembodiment thereof, but

provided, the contact I would have it understood however that the apparatus shown is only illustrative and that the invention may be carried out by other means.

Vhat I claim as new and desire to secure by Letters Patent of the United States, 1s:

1. An electric switch mechanism comprising a plurality of'movable contact fin gers, a relatively movable brldgmg member operable into overlapping contact with each f of said fingers to interconnect the same,

the relative length of overlapping contact with one of said fingers being less than with the other fingers whereby continued operation ofsaid member effects the disengagementnof said one finger and maintains contact with said other fingers, and means for preventing electrical contact with. said one finger upon the return movement of said member. u

2. An electric switch mechanism comprising a contact member operable'between two positions, a plurality of relatively mov-v able contact fingers each biased to a position in, the path of different portions of said member and so proportioned that when the said member is operated from one po:

sition to the other electrical contact is eS-,

tablishedwith all of said fingers at one intermediate position and broken with one of said fingers at a second intermediate posiv tion, and means for preventing electrical contact with said one finger upon the return of said member to the said one position.

3. An electric switch mechanism comprising a pivoted contact member operable between two positions, a plurality of relatively movable contact fingers each biased to a position in the path ofdifi'erent portions of said member, the several portions of said member being so proportioned that when the same is operated from one position to the other electrical contact is established with all of said fingers at an intermediate position and is broken with one of said fingers at a second intermediate position, and means for preventing electrical contact with said one finger upon the return of said member to said one position.

4. An electric switch mechanism comprising a pivoted contact member operable between two positions, means for biasing said member to the last position to which it is operated, a plurality of pivoted con tact fingers disposed in spaced relation with the ends thereof'in the path of different portions of said pivoted contact member and arranged to be interconnected thereby when said member is operated from one of said positions to the other, the relative lengths of one of said fingers and the cooperating portion of said contact member being such that the said one finger is disengaged when said member is in the said other position, and means for preventing electrical contact with said one finger upon the return of said member to saidone position.

5. An electric switch mechanism comprising a base, a set of contact fingers pivotally mounted thereon with the ends thereof in spaced alignment, a switch shaft rotatably supported on said base, means for operating said shaft between two positions and biasing the same to the last position to which it is operated, a bridging contact member secured to said shaft and carried thereby int-o simultaneous overlapping electrical contact with each of said fingers when said shaft is operated from one position to an intermediate position, said bridging member having aportion cut away where by upon continued operation of said shaft to the other position one of said fingers is disengaged, and insulating means car ried by said one finger for preventing electrical contact of said bridging member therewith upon the return of said shaft to the said one position.

In witness whereof, I have hereunto set my hand this 8th day of July, 1924.

GEORGE S. LEDDICK.

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