US2129151A - Control apparatus - Google Patents

Description

Sept. 6, 1938. E. c. RANEY 2,129,151

' CONTROL APPARATUS Filed Nov. 8, 1937 INVENTOR Patented Sept. 6, 1938 UNITED STATES PATENT OFFICE CONTROL APPARATUS Estel C. Rancy, Columbus, Ohio, assignor to Ranco Incorporated, Columbus, Ohio, a corporation of Ohio This invention relates to a snap acting mechanism which may be utilized in control apparatus, or any other apparatus in which it may be desirable to provide a positive snap movement in response to relatively slight actuating movement.

, An object of the invention is to provide in a snap acting mechanism, a pair of flipping members, each pivoted at one end and havingaspring connecting the free ends, to bias the members to one side or the other of a dead center position of each member, established relative to its fulcrum and the spring, and providing for moving one of the members past its dead center position to thereby move the second member past its dead center position with a snap action.

It is a further object of the invention to provide a snap acting mechanism, as set forth in the foregoing paragraph, in which the pivots for the flipping members are in different planes, thereby causing one of the members to be moved past its dead center in advance of the other member to cause the latter member to be moved through its dead center position with a snap action.

It is a further object of the invention to provide in a snap acting mechanism, an actuating member and a snapping member, each pivoted at one end, and having a spring connecting the free end of the member for biasing the members to one side or the other of a dead center position of the membars, established relative to the fulcrum of the members and the spring, in which provision is made for moving the free end of the actuating member from one side of its dead center position to the other, through a relatively fixed range of movement, to snap actuate the snap member through its dead center position, and also for increasing the distance of snap movement of the snap member in one direction.

Other and further objects of the invention will be apparent from the following description, reference being bad to the accompanying drawing wherein a preferred form of embodiment of the present invention is clearly set forth.

In the drawing:

a Fig. l is a view, illustrating the position of the members of the mechanism when the mechanism is at one of its limited positions;

Fig. 2 and Fig. 3 are views similar to Fig. 1, wherein the position of the members of the mech- 50 anism are shown, during one phase of operation of the device;

Fig. 5 and Fig. 6 are views similar to Fig. 1, showing the position of the members during a phase of operation of the mechanism in the re- 551 verse direction to that shown in Figs. 2 and 3.

28 and 30.

The invention'is particularly adaptable to be used in thermostatic or pressure control devices and in the present disclosure, I have shown the invention as it might be utilized in a. pressure control device 20. The control device 20, comprises a bell-crank lever 32 pivotally supported at 34 on a part 2| of the frame of the control, the frame not being shown except for the fragmentary part 21. An actuating rod 36 engages the lever in a detent 23, formed in a laterally extend- K ing part 21' of the lever 32, and is actuated in a vertical direction by any suitable means such as, for example, a diaphragm or bellows (not shown) in response to changes in pressures generated in response to actuation of the apparatus controlled by the device. It is to be understood, however, that the invention is in no way dependent upon the source of power used for actuating the rod 36.

A tension spring 38, partially shown in the drawings, is connected to the arm 40 of the lever 32 through the eyelet 29 formed in the lever 4|] and its opposite end is connected to a suitable support (not shown), which may or may not be adjustable to vary the tension of the spring. The spring 38 is adapted to bias the lever 32 clockwise and place a load upon the rod 36. The spring 38 controls the pressures at which the mechanism will be operated.

In the operation of the control device, the rod 36 rotates the lever 32 counterclockwise and the spring 38 acts to rotate the lever 32 clockwise upon decrease in the pressure actuating the rod, thereby operating the snap mechanism to be described presently.

Two pivot members 26, spaced apart, one being directly behind the other as viewed in the drawing, are fixedly supported on the frame of the control apparatus in any suitable manner, and each is provided with V shaped fulcrums 28 and 30, to receive and pivot the ends of two flippers or members 22 and 24. The flippers are preferably U shaped, and disposed with the closed end away from the pivots and the ends of the legs thereof being engaged in the fulcrums 28 and 30. A tension spring 25 is connected at the closed portion of the U, of each of the flippers 22 and 24, and is located betwen the pivot members 26 and the legs of the flippers 22 and 24. The spring 25 and its center of tension is represented by a broken line in Figures 2, 3, 4, 5 and 6. The tension of the spring 25, tending to draw the flippers together, maintains the ends of the flippers in the fulcrums The spring 25 also biases the snap flipper or member 22 against either the fixed member 46 or the endof the finger 44 formed on the lever 22. The member 46 represents any means for controlling. the operation of apparathe, controlled by the device 20, such as, for example, a fuelvalve or any electric switch, which may be opened or closed by the flipper 22 striking or contacting the member 40. a

The pivots 2! and II lie in diflerent horizontal planes, as viewed in the drawings, which causes oneortheotherottheflipperstopassthrough its dead center position, i. e., the position of the flipper when the flipper and spring 2| lie in the same horizontal plane, before the other flipper is moved 'to its dead center position, or in other words, when either one of the flippers is moved to its dead center position, the other or the flippers will remain biased to one side or the other of iti dead center-position. This characteristic is illmtrated iii Figs. 2 and 6, wherein the m a 1. Min its dead center position, while the flipper 22 is biased to-the member 4|, and in Hg. 5, the flipper 22 is in its dead center position while flipper 24 is biased by lever 22,

The operation of the snap acting device is as follows:

When the control device 22 is at one limit of its function, as shown in Fig. 1, the flippers 22 and 24 are biased against member 40 and stop 42 respectively by the spring 2l As the rod 28 is raised, due to a function of the apparatus controlled by the device 2|, the lever 32 is moved counterclockwise. causing the stop 42 to move the flipper 24 upward, as shown in Pig. 2, until the flipper 24 has been moved past its dead center position, and instantaneously thereafter the spring 2| will snap the flipper 24 upward against the stop 4|, as shown in Fig. 8, which movement carries the spring 2' above the pivot 22, thereby causing the spring 2| to snap the flipper 22 upward against the flnger 44 as shown in Fig. 4. It will be noted that when the flipper 24 has been moved to its dead center position, the spring 25 will continue to-exert a substantial pressure on the flipper 22 against the member 40, since the pivot 28- is located in a plane above the pivot 20. when the pressure tending to move the rod 28 upwardly is reduced, the tension of the spring 22 causes the lever 22 to be moved clockwise. This swings the flnger 44 downward, moving the flipper 22 to its dead center position, as shown in Fig. 5, and simultaneously, stop 40 moves the flipper 24 downwardly toward its dead center position. Further movement of the lever 32 by thespring 22 moves the flipper 22 past its dead center position, causing the spring 25 to instantaneously snap the flipper 22 against the member 48. Themovementoi the flipper 22 to the member 48 together with-the movement of stop 4|, carries the spring 2! below the pivot and thereby causes the flipper 24 to be snapped through its dead center position to the stop member 42.

Particular attention is directed to the operation and arrangement of the actuating lever 22 and its members 4|, 42 and 44. Each of the stops 4|, 42 and the flnger 44 are movable to actuate the flippers and to also limit the movement there- 01'. By combining these functions of the members, it is possible to secure a snap mechanism having a relatively substantial snap movement in response to a relatively short movement of the actuating element, as i'orexample, in the present disclosure, the flnger member 44, .being lo-- cated on the end of the lever 22, is moved a relatively greater distance from the end of the flipper 22 upon slight upward movement of the actuating rod 26, so that when the flipper 22 is snapped asainst the flnger 44, the free end oi the flipper will be moved a substantial distance from the member 48, with a snap movement. As

' the lever 22 is moved clockwise, a relative short downward movement oi the rod it permits the member 44 to move the flipper 22to its dead center position from 'which position it is snapped to the member 42. The stop 4i, moving simultaneously with the flnger 44, moves the flipper 24 nearer its dead center so that when the flipper 22 is mapped against the stop 48, the flipper 24 will have been moved'to a position that will allow the spring 25, to snap it against the stop member 42. Thus. by simultaneously moving both flippers toward, andthrough their dead center positionsrespectively, the movement oithe actuating rod 28 may be eflectively multiplied to produce a positive snap action of the flippers.

The wide opening of the flipper 22 is especially desirable ii the device is utilized as an electric switch, in which the flipper 22 carries a contact for making the electric circuit at 48. The wide brake or the contact permits a high current rat-- ing for the switch due to the instantaneous and wide movement of the flipper 22 away from 48.

Although one form of the invention is disclosed, it is to be understood that changes may be made in the form and use 01' the invention and yet fall within the scope is set forth in the claims.

1. In a snap acting device, a pair or members each pivoted at one end thereof; resilient means acting on the free ends of the members to bias the members to one side or the other of a dead center position with respect to the member, its pivot and the line of iorce of the resilient means; and actuating means enga ing each of said members adjacent the free ends thereof for moving the members toward their dead center position, said actuating means being adapted to move one oi the members past its dead center position to cause the last mentioned member to snap the other member past its dead center position.

2. In a snap acting device, a pair oi members each pivoted at one" end thereof; resilient means acting on the free ends 0'! the members to bias the members to one side or the other of a dead center position with respect to the member, its pivot and the line of force 01' the resilient means; and actuating means engaging the members adjacent their free ends for. moving one of the members past its dead center position and simultaneously moving the other of the members tooi my invention which I ward its dead center position.

in one direction to cause the members to be moved past their dead center positions and for engaging only one of the members to move the same past its dead center position in the opposite direction when the actuating means is actuated in the reverse direction.

4. In a snap acting device, a pair of flippers; each of the flippers being pivoted at one end thereof; resilient means connecting the flippers adjacent the free ends thereof, the flippers each having a dead center position with respect to its pivot and the spring, said resilient means normally acting to bias the flippers to one side or the other of their dead center position; actuating means for engaging one of the flippers adjacent its free end to move the flipper past its dead center position and for engaging the other of the said flippers adjacent its free end for moving the last mentioned flipper toward its dead center position during movement of the actuating means in one direction, and means for moving the actuating means.

5. In a snap acting device, a pair of flippers; each of the flippers being pivoted at one end thereof; resilient means connecting the flippers adjacent the free ends thereof, the flippers each having a dead center position with respect to its pivot and the spring, said resilient means normally acting to bias the flippers to one side or the other of their dead center positions; movable means for engaging each of the flippers adjacent the free ends thereof, when moved in one direction, to move one of the flippers toward its dead center position while simultaneously moving the other of the flippers past its dead center position, said movable means, when moved in the opposite direction engaging one of the elements to move the same past its dead center position, and means for moving the movable means.

6. In a snap acting device, a pair of members each pivoted at one end thereof, a spring connecting the free ends of the members to normally bias the members in one direction, each of the members having a dead center position relative to its pivot and the spring; an actuating element for moving one of the members past its dead center position; a lost motion connection between the actuating element and the member; an element for, engaging the other of the members to move the member past its dead center position while the actuating element moves the first element towards its dead center position; and means for moving the said elements simultaneously.

7. In a snap action device, an actuating member and a snap member, each pivoted atone end thereof; a spring connecting the members,- each member having a dead center position relative to its pivot and the spring; an actuating element, a lost motion connection between the element and the actuating member, the element being operative to move the actuating member past itsv dead center position and thereby snap actuate the snap member, a. movable element for moving the snap member past its dead center position when the element is moved in one direction; means for actuating said elements simultaneously, and for moving the actuating member past its dead center before the snap member ismoved to its dead center position, to cause the actuating member and spring to move the snap member past its dead center position with a snap action.

8. In a snap acting device, a pair of members each pivoted at one end; a resilient element connecting the free ends of the members for biasing the members in either of two positions; means for simultaneously engaging each of the members adjacent the free ends thereof for moving the members from one of said positions to cause the resilient element to bias the members to the other of the said positions with a snap movement; and means for moving the last mentioned means.

9. In a snap acting device, a pair of members each pivoted at one end, a resilient element connecting the free ends for biasing the members in either of two limited positions, each of the members having a dead center position relative to its pivot and the resilient element, said pivots lying in different planes; movable means for engaging the free end of one of the members to move it from one of said limited positions through its dead center and for engaging the free end of the other member to move the last mentioned member toward its dead center position; and means for moving the last named means.

1 0. In a snap acting device, a pair of members each pivoted at one end thereof; resilient means acting on the free ends of the members to bias the members to one side or the other of a dead center position with respect to the member, its pivot and the spring; stops for limiting movement of the free ends of the members about thepivots; and means for moving one of the stops to move one of the members past its dead center position to cause snap movement of the other of the members, and for simultaneously moving one of the stops for the latter member.

11. In a snap acting device, a pair of members each pivoted at one end thereof; resilient means acting on the free ends of the members to bias the members to one side or the other of a dead center position with respect to the member, its pivot and the spring; stops for limiting movement of the free ends of the members about the pivots; means for moving the stops of one of the members to move the member past its dead center position, and snap actuate the other of the members; and means for moving one of the stops for the latter element prior to the said snap movement thereof.

12. In a snap acting device, a pair of members each pivoted at one end thereof, resilient means acting on the free ends of the members to bias the members to one side or the other of a dead center position with respect to the member, itsvpivot and the spring; stops for limiting movement'of the free ends of the members about the pivots; means for moving the stops of one of the members to move the member past its dead center position, and snap actuate the other of the members; and means for moving one of the stops for the latter member away from said member prior to the snap movement thereof by the

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