US2202429A

US2202429A - Control apparatus

Info

Publication number: US2202429A
Application number: US217367A
Authority: US
Inventors: Estel C Raney
Original assignee: Ranco Inc
Current assignee: Robertshaw US Holding Corp
Priority date: 1938-07-05
Filing date: 1938-07-05
Publication date: 1940-05-28
Anticipated expiration: 1957-05-28

Description

Patented May 28, 1 940 PATENT ornca 2,202,429 CONTROL APPARATUS Estel C. .Raney, Columbus, Ohio, assignorto Ranco Incorporated, Columbus, Ohio, at corporation of Ohio Application July 5, 1938, Serial No. 211,367

12 Claims. This invention relates to. a snap acting device,

and more particularly to a pressure operated snap switch.

An object of this invention is to provide a snap 5 device having a fulcrumed member and a pivoted flipper, the flipper being connected to the member by a lost motion connection, and resilient means for imparting a snap action to the flipper so the flipper will impart a. force through the lost motion connection to move the fulcrumed member. A further object of this invention is to provide a snap acting device having a fulcrumed member and a flipper pivoted on the member and having its free end connected to the member by a lost 15 motion connection, a spring being connected to the flipper and an actuating member so that the spring may be moved by the actuating member to cause a snap movement of the flipper which further moves the spring with respect to the fulcrum 2 of-the member to cause snap movement of the member about its fulcrum.

A still further object of the invention is to provide a snap acting device as set forth in the preceding paragraph having the parts arranged so i that the line of force of the spring will remain on one side of a line between the fulcrum of the member and the point of connection of thespring with the actuating member during the time the line of force, of the spring is passing a line I throughthe point of connection of the spring with the flipper and the pivot for the flipper, and thereafter be moved past the mentioned line through the fulcrum by snap movement of the flippen,

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

In thedrawing:

Fig. 1 is a view taken on line l--l of Fig. 2, showing a pressure operated switch embodying the invention;

Fig. 2 is a view taken on line 22 of Fig. 1;

' Fig. 3 is an exaggerated diagrammatic view illustrating the position of the parts of the snap switch with the switch in the closed position;

Fig. 4 is a view similar to that of Fig. 3, illustrating the position of the parts just prior to the openingof the switch;

I Fig. 5 is a view similar to that of Fig. 3 illust'rating the positions of the parts of the switch immediately after the switch has opened; and

Fig. 6 is a view similar to that of Fig. 3 illustrating the positions of the parts of the switch just prior to the closing of the switch.

A pressure operated control apparatus is shown at l0. The apparatus comprises generally, a base member l2, 9. pressure responsive device H, a

switch actuating member 16 and a snap switch The base I2 is preferably formed of insulating material such as hard rubber or Bakelite. A U

shaped bracket 20 is secured to the base l2 by rivets or screws, not shown, and having the legs 2| thereof extending upwardly. The actuating member I6 is formed with two

arms

22 and 24, which extend at substantially right angles to one another. The-member I6 is also formed with a flange part 26 having a turned edge 28. The member I6 is pivotallysupported by a pin- 30 extending through openings adjacent the ends of the legs 2| and the turned edge 28 and the base section of the

arms

22 and 24. The flange 26 has a detent 3i formed therein for receiving the end of a push rod 32 connected to a bellows IS. A spring as has one end attached to the arm 22 and its other end attached to a suitable support, not shown, so that the spring 36 will con.- tinually bias the member It in a clockwise direction about its pivot formedby the pin 30. The arm 24 is formed with a depending lu'g 31 and' finger 38, the purpose of which will be set forth hereinbelow.

The pressure responsive device l4 comprises an expansible bellows l3 enclosed in a metal housing IS, the housing being suitably attached to the bottom side of the base I2. I The bellows I! may be connected to a source of pressure, generated in response to the operation of the control apparatus, by a tube IS. The push rod 22 is suitably connected to a movable wall of the bellows l3 and extends upwardly through openings 21 in the base l2 and the bracket 20 to engage in the detent 3|. Thus the bellows I 2 will tend to rotate the actuating member l6 counterclockwise and against the resistance of the spring 36 in response to an increase of pressure therein.

A bracket 40 having a pair of upright legs 41 is suitably anchored to the base l2 for supporting the snap switch IS. The legs 4| each have a V notch 44 formed adjacent the ends thereof which notches serve as a fulcrum for a switch member 45. The switch member 45 is U shaped and is provided with turned edges 48 on each side thereofwhich extend beyond the ends of flat legs 41 formed on the member. The ends of the legs 41 are beveled and engage in the V notches 44. The extended edges 46 have inturned lugs 48 formed on the ends thereof which serve as a pivot support for a flipper 56. Afiber strip 50 is attached to the yoke of the switch member 45 by extending a narrowed end of the strip through an opening in the yokeand then crimping the end of the fiber on the upper side of the yoke, as shown at 5|. A contact bar 52 is attached to the flber strip 50 and is adapted to bridge a pair of stationary contacts 53 which are secured to the base I2. The contacts 83 are ex,-

tended through the base l2 and are provided with terminal connectors 54 for connecting the contacts in a circuit of the mechanism which is to be iii) controlled by the pressure switch. The flipper 56 comprises a flat member 58 having a pair of upturned lugs 59 formed at one end and adjacent the two corners thereof. These lugs 59 each have a V notch 60 formed therein which receives an edge of one of the lugs 48.

The flipper 56 is formed with down turned edges 62 extending along each side thereof to reenforce the member. A c shaped member 64 is formed at one end of the flipper 56 and is provided with two

jaws

65 and 66. These jaws are adapted to engage the yoke of the member 45 and move the member about its fulcrum when the flipper 56 is actuated. The spaced

jaws

65 and 66 provide a lost motion connection between the flipper 56 and the fulcrumed member 45 and limit the movement of the flipper 56 about its pivot. The flipper 56 is connected to the actuating member 16 by a tension spring 68 which'is connected to the member 64 and to the end .of the finger 38. The spring 68 biases the flipper 56 against the pivot lugs 48 of the switch member 45 which in turn biases the member 45 in its fulcrum formed by the V notches 44.

Assuming that the control apparatus 20 is adapted to operate an air compressor and the bellows l3 isconnected to the air tank (-not shown) by the tube 19, the operation of. the switch will be as follows:

If the air pressure .is low the switch I8 will be closed as shown in Fig. 3; and cause operation of the compressor. As the air pressure is built up in the air tank, the bellows I3 expands against the tension of the spring 36 and raises the arm 24 upwardly as shown in Fig. 4. The spring 68 will be raised so that the center of force thereof, illustrated by line as in 'Figs.' 3, 4, and 6, will be raised above the pivot of the flipper 56 to initiate the snap movement of the flipper. During this movement the spring 68 will arrive at a dead center with respect to the flipper when the spring is on a line with the point of its connection with the flipper and the pivot for the flipper. When this dead center position is reached, the bias of'the flipper on the switch 45 through the jaw 66 will be zero. Contact pressure will be maintained, however, since the spring 68 is yet below the fulcrum 44 and will, therefore, in biasing the flipper 56 to its pivot. tend to raise the end of the member 45, and bias the member 45 about its pivot 44 counterclockwise; When the flipper 56 is snapped by the spring moving beyond the dead centerposition the lower jaw 65 will strike the underside of the member 45 and simultaneously move the center of the spring 68 above the fulcrum 44.

Thus the spring 68 will .be moved from one side of the fulcrum of'the switch member 45 to the other with a snap movement and cause the member 45 to be snapped upwardly against the lug 31, and open the switch as 'shown in Fig. 5. When the switch is in the open position, the spring 68 is above the fulcrum 44 and it will bias the member 45 clockwise through the flipper 56. As the pressure of the air in the storage tank decreases, the tension of the spring 36 will tend to lower the arm 24. As the arm 24 is lowered the lug iii-moves the member 45 downwardly and the finger 38 lowers the center ofthe spring 66 until its center is moved below the pivot 48 of the flipper, as shown in exaggeration in Fig. 6, thereupon the flipper will-be snapped bination, means forming a pivot;

past its dead center, causing the upper jaw 66 to strike the upper side of the'yoke of the member 45 and also throwing the center of the spring 68 below the fulcrum44 of the member 45 with a snap movement so that the tension of the spring 68 acting on the flipper 56 will tendto rotate the member 45 against the contacts 53 and close the switch. The jaw 66 striking the above the fulcrum 44 during its movement.

through its dead center position of the fulcrum and thereby bias the member 45 clockwise about the fulcrum 44 to maintain the member '45,

against the lug 3'! until the spring is moved below the fulcrum. 1

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms mightbe adopted all coming within the scope of the claims which follow. 4

I claim: a

1. Ina snap acting device, a snap member; a fulcrum for the member; a flipper; a pivot for the flipper; lost motion connecting means for connecting the free end of the flipper with the fulcrumed member; resilient .means connected to the flipper for snap actuating the flipper, the fulcrum for the said member being disposed intermediate the flipper pivot and the point of connection of the resilient means with the fli'pper; and means for moving the resilient means with respect to the said pivot and fulcrum.

. 2. In a snap acting device, a snap member;

a fulcrum for the snap member; a flipper; means with the flipper; and means for moving the resilient means with respect to the said pivot and fulcrum. I

3. In a snap acting de ice, a snap member, a fulcrum for the member; a flipper; means for pivoting the flipper on the member; a lost motion connection between the free end of the flipper and the member; an actuating member; and a spring connected to the flipper adjacent the free end thereof and theactuating member, said spring being moved by the actuating member so that the line of force of the spring is moved to one side of a line through the point of connection of the spring with the flipper and the pivot means and moved by the flipper to'one side of a line through the fulcrum for the said I snap member and the point of connection of the spring with the actuating member. 4

4. A snap acting device comprising in coma member fulcrumed thereon; and movable therewith; a flipper fulcrumed on the last mentioned pivot, said flipper having a part for engaging the member to limit rotation of the flipper in one direction about its pivot; means for limiting rotation of the flipper in the opposite direction; means for constantly biasing the flipper toward its pivot, said flipper, when in one position being biased toward its pivot for urging the said member about its pivot in one direction and when in another position being biased toward its pivot for urging a pivot on said member.

the said member about its pivot in the opposite direction; and actuating means including the biasing means for snap actuating the flipper from one position to the other.

5. A snap acting device comprising in combination, means forming a pivot; a,member fulcrumedon the pivot; a pivot on said member and movable therewith, a flipper fulcrumed on the last mentioned pivot, said flipper having a .part for engaging a part of the member to limit rotation of the flipper in one direction about its pivot, the pivot for said member being disposed intermediate said engaging parts and the pivot for the flipper; means for limiting rotation of the flipper in the opposite direction; means for constantly biasing the flipper toward its pivot, said flipper, when in one position being biased toward its pivot for urging the said member about its pivot in one direction and when in another position being biased toward its pivot for urging the-said member about its pivot in the opposite direction, and actuating means including the biasing means for snap actuating the flipper from one position to the other.

6. A snap acting device comprising in'combination, means forming a pivot; a member fulcrumed on the pivot; a pivot on the member and movable therewith; a flipper fulcrumed on the last mentioned pivot, said flipper having parts for engaging the member to limit rotation of the flipper about its pivot in opposite directions; means for constantly biasing the flipper toward its pivot, said flipper, when in one position being biased toward its pivot and about its pivot for urgingthe member in one direction about its fulcrum, and when in another position being biased toward its pivot and about its pivot for urging the said member about its fulcrum in the opposite direction; and actuating means including the biasing means for snap actuating the flipper from one position to the other.

7. A snap acting device comprising in combi nation, means forming a pivot; a member fulcrumed thereon; a pivot on said member and movable therewith; a flipper pivoted on the said last mentioned pivot, said flipper and member having engaging parts for limiting rotation of the flipper about its pivot in opposite directions; a movable element; a spring connecting the element and flipper for biasing the member about its pivot, said spring, flipper and element having a dead center position; said movable element being adapted to move the spring through the dead center position'for biasing the flipper about its pivot from one of its limits to the other with a snap action, said flipper during said snap action, moving the center of force of the spring on said member from one side to the other of a line through the fulcrum of the member, and the point of connection of the spring with the element; and actuating means for moving said element.

8. A snap acting device comprising in combination, means forming a pivot; a member fulcrumed on the pivot; a pivot on said member and movable therewith; a flipper fulcrumed on the last mentioned pivot; means for limiting rotation of the flipper about its pivot in opposite directions; a movable element; a spring connecting the element and flipper for biasing the member about its pivot, said spring, flipper andele-' ment having a dead center position, said element tion, moving the center of force of the spring on said member from one side to the other of a line through the fulcrum of the member and the point of connection of the spring with the element; and actuating means for moving the element.

9. In a snap acting device, a snap member, a fulcrum for the member; a flipper; pivot means for pivoting the flipper on the member; a lost motion connection between the free end of the flipper and the member; an actuating member; and a spring connecting the flipper and the actuating member, said spring'being moved by the actuating member so that the line of force of the spring is moved from one side to the otherof a line. through the point of connection of the spring with the flipper and the pivot means and said spring being moved by the flipper so that the line of force of the spring is moved from one side to the other of a line through the fulcrum for the said snap member and the point of connection of the spring with the actuating member.

10. A snap acting device comprising in'combination, means forming a pivot; a member fulcrumed on the pivot; a pivot on the member and movable therewith; a flipper pivoted on the last mentioned pivot, said flipper having apart for engaging the member to limit rotation of the flipper in one direction about its pivot; means for limiting rotation of the flipper in the opposite direction; a movable element; and a spring connecting the element and flipper for biasing the member about its .pivot, said spring also biasing the flipper about its pivot; in one direction when the flipper is at one of its limits and said spring being moved by the element through a dead center position with the flipper for snapping the'flipper to the other of its limits, said snap movement -of the flipper carrying the center of force of the spring from one side to the other side of a line through the point of connection of the spring with the element and the fulcrum for the member; and actuating means for moving the, said element.

11. In a snap acting device, a snap member; a

fulcrum for the member; a flipper; a pivot for the flipper; lost motion connecting means for connecting the free portion of the flipper with the fulcrumed member; resilient means connected to the flipper for snap actuating the flipper, the fulcrum for the said member being disposed intermediate the flipper pivot and the lost motion connecting means; and actuating means for moving the resilient means with respect to the said pivot and fulcrum.

12. In a snap acting device, a snap member; a fulcrum for the snap member; a flipper; means for pivoting the flipper on the member; lost motion connecting means for connecting the free end of the flipper with the snap member; resilient means connected to the flipper for actuating the flipper, the fulcrum for the said member being disposedintermediate the pivot means and the lost motion connecting means; and actuating means for moving the resilient means with respect to the said pivot and fulcrum.'

ns'rn c. RANEY;