US2809537A

US2809537A - Manual switch

Info

Publication number: US2809537A
Application number: US427066A
Authority: US
Inventors: William H Jette
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1954-05-03
Filing date: 1954-05-03
Publication date: 1957-10-15
Anticipated expiration: 1974-10-15

Description

Oct. 15, 1957 w. H. JETTE MANUAL swn-ca Filed May 3, 1954 2,809,537 Patented Oct. 15, .1957

MANUAL SWITCH William H. Jette, "Pittsfield, Mass., assigner to General Electric Company, a corporation of New York .ApplicationMay 3, 1954, Serial No.'427,066

-4 Claims. -(Cl. 74483) Ihisinvention-relates to-a manual switch. More par- .ticularlyQ-it relates to 'a -manual switch having at least three positions which can not be moved through an interme'diate position Without stopping briefly on the intermediate position.

There are many-mechanical and electrical switch move- -ments Where proper operationrequires that the operator hold the switch lever momentarily 'at an intermediate point in efiecting a.change between extreme points. For

example, many electric motors havea forward, off, and reverse switch, the offposition being between the" forward and reverse positions. If the motor is operating forward and the switch is quickly thrown to reverseposition, the motor will continue its forward opaeration due to the fact that its speed'did not decline suf- -ficieritlytor thestarting mechanism to come-into opera- 1 tion and apply areverse-torque. In order to bring-about reversal ofthe-motor, it is necessary for the operator -'to hold his switching lever in an intermediate position for a shortperiod-oftime before proceeding tothe reverse position. In many'ship speed controls, the rapid move- -ment'of the leverfrom aforward speed position to a reverse speedposition will fail to reverse the-engines. 'In transformer tap changer switches, 'it is frequently desirable-that the operator allow theswitch lever to pause -=briefly at 1 intermediate switch points.

In many installations, the failure of the operator to allow the switch. lever .to pause briefly at an intermediate switch 'pointwill result in damageto the controlled apparatus. Accordingly, it:is one.of:the objects of this invention to provide a manual switch which compelsgan zoperatortozstop the switch lever ,at intermediate-switch points during movement of the switch between extreme points.

It is another object of the invention to provide a manual switch control arrangement for the mechanical interlocking of two controlled circuits.

The above and other objects of the invention will be apparent from the following description and annexed drawing wherein:

Fig. 1 is a perspective view of a mechanical switching device;

Fig. 2 is a partially broken fragmentary side elevation showing the switch lever in intermediate position; and Fig. 3 is a fragmentary side elevation similar to Fig. 2 except that the switch lever has been advanced to a terminating position.

Briefly stated, in accordance with one of its aspects, my invention is directed to a switch rotatable to at least three positions comprising a shaft rotatably mounted with respect to a base element, a cranking lever fixedly mounted on the shaft for rotating the shaft, a boss protruding from the lever in an axial direction with respect to the shaft, a scalloped cam fixedly mounted on the shaft, the scalloped portion of the cam being in radial alignment with the lever, and a stopping cam rotatably mounted with respect to the base element with its axis parallel and offset from the shaftaxis and in spaced relation with the scalloped cam and boss, the stopping cam'being of substantially circular configuration with oppositely disposed sections removed whereby the stopping cam is free to rotate only whein the scalloped portion of the scalloped cam is aligned between the axes of the two earns, the stopping cam having a peripheral protrusion between the oppositely disposed sections, the protrusion "being-engageable by the boss whereby the shaft cannot be rotated past the stopping cam untilithe stopping cam has been rotated to remove the peripheral protrusion from engagement with the boss.

Referring to Fig. 1, a base element .10 has mounted thereon a bearing 11 and a bearing12, the two bearing -axes beingparallel and the axis of thebearing 12-being positioneda greater distance from the base element 10 than'the axis of the bearingll. A rotatable shaft '13 passingthrough the bearing 11 has a cranking lever or .switch arm 14 fixedly mounted thereon and extending :radially outward therefrom, the lever 14 terminating in a handhold 15. The lever 14 includes a boss16 extending axially outward therefrom at a pointabout midway .between the handhold 15 and shaft13.

Also fixedly mounted upon the rotatable shaft 13-is a scalloped .cam 17, the scalloped portion 18 of the ,cam

"19 and

switch contacts

21, 22, and 23. Rotatablypass- "ing through the bearing 12 is a stepping cam '25 positioned in spaced relationship to the scalloped cam '17.

:The stopping cam 25 is of generally circular configuration with a pair of oppositely disposed cutout portions'26 and 27. A peripheral projection 28 extends axially outward from the cam 25 at apoint between the cutoutportions 26 and '27,. the projection'28 being in engageable relation with the boss 16 of the lever arm 14. A knurled handwheel 29 is fixedly positioned with respect .to the stopping cam 25 and is utilized to control the rotation of .the cam.

The operation of the device will now be described with .reference to movement of the lever arm from the position'illustrated in Fig. .1 to .that'illustrated in'lFig. 3.

As the operator movesthe'lever arm tothe vertical position illustrated in Fig. 2, theiboss 16 encounters the peripheral pro'jection28 "forcing a stop at 'the'interme'diate position. The cutout 18 of the cam 17 is now lined up between the two cam axes and the stopping cam 25 is rotated 180 by means of the handwheel 29. The operator may then advance the lever to the position shown in Fig. 3, further rotation of the stopping cam being prevented by movement of the scalloped portion 18 of the cam 17 out of alignment with the cam axes. Upon the return of the lever arm to the position illustrated in Fig. 1, the peripheral projection 28 of the cam 25 again engages the boss 16 of the lever arm 14 and prevents passage through the intermediate position of Fig. 2 until such time as the operator again rotates the stopping cam 25 through an angle of 180. Obviously, there can be more than one intermediate position with a stopping cam arrangement similar to that illustrated provided the switch has more than three contacts. If desired, the shaft upon which the stopping cam 25 is mounted may be made to perform a switching function in which case the device functions as a mechanical switch interlock.

It will be noted that cam 25 performs the double func tion of positively stopping rotation of the switch at its midposition for either direction of rotation and positively holding the switch in its midposition while the cam is being turned from its stop position for one direction of 3 7 switch rotation (Figs. 1 and 2) to its stop position for the other direction of switch rotation (Fig. 3). The holding action is produced by the meshing of the rounded surfaces of cam 25 with the cutout portion 18 of cam 17. As'the

flattened surfaces

26 and 27 of cam 25 prevent rotation of cam 25 except when the switch is in its midposition, it is impossible for boss 16to get on the wrong or back side of projection 28. f

While the present invention has been described with reference to a particular embodiment thereof, it will be understood that numerous modifications may be made by those skilled in the art without actually departing from the invention. Therefore, I aim in the appended claims to cover all such equivalent variations as come within the true spirit and scope of the foregoing disclosure.

What I claim as new and desire to secure by Letters Patent of the United States is: r i t 1. In a manually operated switch having at least three positions, a shaft rotatablyttnounted with respect to a base element, a cranking lever fixedly mounted on said shaft forrotating said shaft,ta boss protruding from said lever in, an axial direction with respect to said shaft, a scalloped cam fixedly mounted on said shaft, the scalloped portion ofsaid cam being in radial alignment with said lever, and a stopping cam rotatably mounted with respect to said base element axially parallel in offset relationship with said shaft axis and in spaced relation with said scalloped cam and boss, said stopping cam being of substantially circular configuration with oppositely disposed sections removed whereby said stopping cam is free to rotate only when the scalloped portion of said scalloped cam is aligned between the axes of said cams, said stopping cam having a peripheral protrusion between the oppositely disposed removed sections, said protrusion being engageable by said boss whereby said lever cannot be rotated past said stopping cam until said stopping cam has been rotated 180 to remove said peripheral protrusion from engagement with said boss.

2. In a manually operated switch having at least three positions, a rotatable shaft with a cranking lever fixedly mounted thereon, a boss extending outward from said lever in an axial direction toward one end of said shaft, a scalloped cam fixedly mounted on said one end of said shaft outward of said cranking lever, the cutout portion of said cam being in radial alignment with said cranking lever, a stopping cam rotatably mounted oifset from said shaft and axially parallel therewith, said stopbeing in spaced relation with said scalloped cam whereby said stopping cam is free to rotate only when the cutout ping cam having oppositely disposed cutout portions and portion of said scalloped cam is in alignment between the axes of said cams and said scalloped cam is rotatable only when a cutout portion of said stopping cam is in rotatable shaft, a positioning lever fixedly mounted on 7 said shaft and extending radially outward therefrom, a boss extending outward from said lever in an axial direction toward one end of said shaft, a scalloped cam fixedly mounted on said one end of said shaft outward of said lever, the cutout portion of said cam being in radial alignment with said positioning lever, and 'a stopping cam rotatably mounted in a position axially parallel to ,said shaft and axially displaced therefrom in adirection corresponding to said intermediate position, said stopping cam being of substantially circular configuration with two oppositely disposed chord-shaped cutout portions in spaced relation with said scalloped cam whereby -'said scalloped cam is rotatable only when said chordshaped cutout portions are positioned with their surfaces perpendicular to a plane parallel to the two cam axes and said stopping cam is rotatable only when the scalloped portion of said scalloped cam is positioned between the axes of said cams, said stopping cam having a peripheral projection between said cutout portions and extending toward said lever, said projection being in spaced relation to said boss to stop said boss during rotation of said shaft to said intermediate position whereby said lever cannot be rotated past said intermediate position until said stopping cam is rotated to remove said projection from the travel path of saidboss and meanson said stopping 'cam outward of said lever for rotating said stopping cam.

4. The switch actuating mechanism of claim 3 wherein the scalloped portion of the scalloped cam has a radius of curvature slightly greater than the radius of curvature of the stopping cam.

' References Cited in the file of this patent UNITED STATES PATENTS Williams July 26, 1921 Williams Feb. 3, 1948