US2982830A - Switch mechanism - Google Patents

Description

y 1961 c. A. SCHAEFER ET AL 2,982,830

SWITCH MECHANISM Filed May 4, 1959 INVENTOR.

CARL A. SCHAEFER WALTER c. KflECH BY Fig-l United States Patent SWITCH MECHANISM Carl A. Schaefer, Whitefish Bay, and Walter C. Karch, Milwaukee, Wis., assignors to Square D Company, Detroit, Mich, a corporation of Michigan Filed May 4, 1959, Ser. No. 810,786

9 Claims. (Cl. 20083) The invention relates to a pressure sensitive switch in which a single electrical switch operating member is responsive to pressure within a certain range as well as pressures above and below that certain range.

In many instances it is necessary to provide signalling systems which will signal or indicate when the pressure of fluid or gas in a container, for example a pipe line, vehicle tire, tube or the like increases, decreases or otherwise deviates from a predetermined desired pressure. In

many instances, dangerous conditions will exist if the pressure of the fluid or gas within a container deviates from the desired predetermined pressure. Prior to the present invention various transducers and pressure sensitive switches were used which would respond to a change in pressure to operate a switch or provide a signal. These prior transducers or pressure sensitive switches were designed to operate on a change in pressure in one direction only. For example, the switch would be operated if the pressure in the container increased above a certain predetermined pressure, or the switch would be designed to operate when the pressure decreased below a certain pressure. In these prior designs a single switch would not operate in both directions of changes in pressure. More specifically, it required two switches and two pressure sensing devices to indicate deviations in pressure in both an increasing pressure direction and the decreasing pressure direction.

One of the main objects of the present invention is to overcome the aforementioned problems and to provide a single pressure sensitive device having a single switch which is operative by deviation of the pressure in either and both the increasing and decreasing directions.

Another object of the present invention is to provide a pressure sensing device which is simple in construction, economical to manufacture and positive in its operation of operating a switch in response to deviations in pressure in both an increasing pressure direction and a decreasing pressure direction.

Other objects and a fuller understanding of this invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings in which:

Figure 1 is a front view illustrating the structure of the invention and with certain parts in cross section;

Figure 2 is an end view of one end of the structure of Figure 1;

Figure 3 is an end view of the other end of the structure in Figmre 1; and

Figure 4 illustrates a modification of the pushbutton operating levers.

The description, drawings, and claims jointly set forth one or more embodiments of the present invention and the present contribution to the art of making a pressure sensitive switch for the purpose as herein set forth. As illustrated in the drawings, for the purpose of exemplification and not of limitation, the invention comprises a pressure operated mechanism for depressing push button 11 of a. suitable snap action switch 12. The snap action switch 12, which may be of any suitable design commonly on the market, has a push button 11 for causing actuation of the switch upon depressing of the push button in a direction upwardly in Figure 1 and thus towards the center of the switch 12. The operating mechanism 10 and the switch 12 are supported in cooperative arrangement by a pair of spaced parallel plates 13 and 13. The switch 12 is mounted on the top edges of these plates 13 and 13' and an attacher 14 is provided at one end of the plates for attaching the entire device to a pipe or other similar container which contains fluid, gas or liquid under pressure. Enclosed in and attached around the periphery thereof to the attacher 14 is a pressure responsive means or diaphragm 16, one side of which is exposed to the pressure in the container.

The operating mechanism 10 includes a plunger 15 having a head 15' seated against the other side of the pressure responsive means or diaphragm 16 and biased thereagainst by a biasing spring 17. Attached to the respective opposite ends of plunger 15 are bell cranks 18 and 19 which include switch operating levers 20 and 21, respectively. These operating levers 20 and 21 engage the push button 11 and extend from their respective bell cranks 18 and 19 substantially in a common plane towards each other and parallel to plunger 15 when the pressure in the container and against diaphragm 16 is at a predetermined pressure. The bell crank 18 is mounted on a pivot 22 extending between parallel elements 13 and 13 and is secured by a pivot pin 23 to the respective end of plunger 15. Bell crank 19 is pivoted by a pivot pin 24 to parallel elements 13 and 13' also to plunger 15 by means of a pivot pin 25. It is noted that the spring 17, plunger 15, bell cranks 18 and 19, operating levers 20 and 21 and push button 11 are all disposed between parallel elements 13 and 13'. In eifect, the plunger 15 and operating levers 20 and 21 form opposite sides of a parallelogram, the ends of which are formed by bell cranks 18 and 19.

Referring to Figure 1 it is noted that if the plunger 15 is moved to the right both bell cranks 18 and 19 will be pivoted on their respective pivot pins 22 and 24, causing operating lever 20* to move downwardly and away from push button 11, and simultaneously causing operating lever 21 to move upwardly to depress push button 11, thereby operating switch 12. On the other hand if plunger 15 moves to the left in Figure 1, bell cranks 18 and 19 will pivot about their respective pivot pins 22 and 24, causing operating lever 21 to move away from push button 11 and causing operating lever 20 to depress push button 11 and again operate switch 12. It is thus apparent that the objects of the invention are met by movement of the plunger 15 in either direction along the axis of its length.

Since the plunger 15 extends beyond bell crank 19 and thus externally of the parallelogram formed by the plunger, bell cranks and operating levers, and is seated against the diaphragm 16, it may be moved in one of these directions, and in this instance to the right in Figure 1, by exerting pressure against diaphragm 16, and is moved to the left, or opposite direction, by spring 17. The spring 17 exerts pressure in a direction to the left by covering one end of the spring with a plate 26 which engages bell crank 19 on the side of plunger 15 opposite pivot pin 24. The spring 17 is compressed between the plate 26 and an adjustment nut 27 mounted on a bolt 28 which extends through spring 17 and is fixed relative to the suitable pipe attacher 14.

Fine adjustments of the position of operating levers 20 and 21 relative to plunger 15 may be had by making operating levers 20 and 21 out of a springable material and providing respective adjustment means 30 and 31, one for each lever. The adjustment means 30 consists of a .nut 32 carried by bell crank 18 anda set screw .33 threaded therethrough and abutting against operating lever 20 to adjustably set operating lever 29 either closer to or further away from push button 11 when plunger is in a desired position. The adjustment means 31 consists of a nut'34 carried by bell crank 19 and a .set screw 35 threaded therethrough-and abutting against operating lever 21 to adjustably set operating lever 2!} either closer to or further away from .push button 11 when plunger .15 isin the desired position. In this way both levers 2t) and 21 may be simultaneously abutted against button 11 at any desired pressure setting wherein the pressure against diaphragm 16 positions plunger 15 at a certain position along its axial line of permissible movement.

In Figure 4 a modification of .the operating levers is illustrated wherein each lever extends across push button '11. The end of lever a has a narrow portion 2% lying alongside a narrow portion 21b on the end of lever 21a. With this construction the levers will exert pressure closer to the axis of the pushbutton at all positions in their operative movement and an edge of a lever does not scrape the end of the button 11 during operation.

In operation the pressure sensing device is simply installed on a pressure line, any other container having fluid under pressure contained therein in such manner that the pressure in the container operates through pipe attacher 14 against diaphragm :16 to urge diaphragm 16 to the right in Figure 1. This causes a movement of plunger 15 to the right until a balance is obtained with spring 17 at a desired pressure setting. Adjustment means 3t] and 31 and adjustment nut 27 are then adjusted so that the balance condition, wherein operating levers 2th and 21 engage, but do not exert pressure, on push button 11 is obtained. When this condition exists the pressure sensing switch is adjusted so that swicth 12 is in one of its positions, i.e. either open or closed, when the pressure against diaphragm 16 is at the predetermined desired pressure. If the pressure against diaphragm 16 decreases, spring 17 will cause movement of plunger 15 to the left, and ultimately depression of push button 11 by operating lever 26 to operate switch 12. Conversely if the pressure against diaphragm 16 increases, diaphragm 16 will push plunger '15 to the right against spring 17, and cause depression of push button 11 by operating lever 21 to operate switch 12. 'Thus switch 12 is automatically operated by a pressure different from the desired pressure, .or when the pressure deviates from the desired pressure. Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

1. In a pressure sensitive switch having an electrical switch provided with an operating push button, the provision of support means, first and second elements operatively carried by said support means and engageable with the push button for operating the button, a member movable relative to said support means and coupled to said elements and movable in opposite directions to simultaneously move one of said elements against said button and the other of said elements away from said button, spring means urging said member in one of said directions, and pressure responsive means urging said member in the opposite direction and against the urging of said spring means.

2. A pressure sensitive device responsive to pressures outside the limits a preselected pressure range having; an electrical switch provided with an operating push button, structure supporting said switch, the provision of first and second lever means pivoted on said structure and engageable with the push button for operating the button 4 upon movement of the lever means, a .member operatively coupled to said lever means and movable in opposite directions to pivotally move said lever means to simultaneously move one of said lever means against said button and the other of said lever means away from said button, spring means urging said member in one of said directions, and pressure responsive means urging said member in the opposite direction and against the urging of said spring means, said spring means and said pressure responsive means being in counterbalance when said pressure responsive means responds to pressures in said preselected pressure range and being out of counterbalance when the pressure responsive means responds to pressure different from pressures in said preselected pressure range thereby eiiecting operation or said operating push button.

3. The structure of claim 2 wherein said lever means are in the form of hell cranks and wherein said members cooperatively are arranged in the form of a parallelogram.

4; The structure of claim 2 wherein said lever means constitute bell cranks and wherein said bell cranks and said member are arranged in the form of a parallelogram, and said member has one end thereof extending externally of said parallelogram and seated against said pressure responsive means, said bell cranks supporting said member for movement axially by said pressure responsive means and said spring means.

5. The structure of claim 2 wherein said lever means have narrow portions disposed alongside each other and each extending across said push button.

6. In-a pressure sensitive switch having an electrical switch provided with an operating push button, the provision of supporting structure supporting said switch, a plurality of hell cranks pivoted on said supporting structure at spaced locations on opposite sides of said push button, all of said bell cranks having button engageable portions extending towards each other and engageable with the push button for operating the button and having member engaging portions, a member pivotally coupled to said member engaging portions and movable in opposite directions to simultaneously pivot all of hell cranks relative to said supporting structure to move one of the button engageable portions against the button and simultaneously move the other button engageable portions away from the button, spring means urging said member in one of said opposite directions, and pressure responsive means urging said member in the other of said opposite directions and against the urging of the spring means, thereby effecting movement of the push button and operation of the switch when the pressure against the pressure responsive means is above or below a predetermined pressure, and thereby to effect release of the push button and release of operation of the switch when the pressure against the pressure responsive means is at a predeter mined pressure wherein said urging of said spring means and pressure sensitive means balance each other.

7. A switch comprising support means, an operating element movable along said support means in a line of movement in one direction, an actuating member reciprocally movable along said support means in opposite directions in a path of movement disposed at an angle to said 'line of movement, first means interposed between said member and said element and operatively carried by said support means to transfer movement of said member in one of said opposite directions to movement of said element in said one direction, second means interposed between said member and said element and operatively carried by said support means to transfer movement of said member in the other of said opposite directions to move said element in said one direction.

8. The structure as defined in claim 7 additionally including the feature wherein said path of movement and said line of movement are transverse to each other.

9. The structure as defined in claim 9 additionally including the feature of biasing means biasing said member in one of said opposite directions and pressure responsive means urging said member in the other of said opposite directions.

References Cited in the file of this patent UNITED STATES PATENTS Crew Sept. 12, 1944 Geisel Sept. 6, 1949 Bordelon Dec. 27, 1949 Grupp Nov. 14, 1950 Spracher Sept. 18, 1956 Mercier Apr. 16, 1957 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,982,830 May 2, 1961 Carl A. Sch aefer et al.

It is hereby certified that error appears in the above numbered pat-- ent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 73,

for the claim reference numeral "9" read 7 Signed and sealed this 14th day of November 1961.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer DAVID L. LADD Commissioner of Patents USCOMM-DC UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION v Patent No, 2,982,830 May 2, 1961 Carl A. Schaefer et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.-

Column 4, line 73, for the claim reference numeral "9" read 7 Signed and sealed this 14th day of November 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer I Commissioner of Patents USCOMM-DC

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