US2028196A - Switch - Google Patents

Description

S. R. DU BRIE Jan. 21, 1936.

SWITCH Filed Oct. 8, 1954 2 Sheets-Sheet 2 INVENTOR JAMA w. BY 4 J ATTORNEY.

Patented 21,

amass swrron Stanley a. D1: Brie, Detroit. that. Application mm tarsal, Serial No. 741.413

. Claims. (or 200-83) The switch disclosed in this application is of the pressure type and is operated automatically for circuit breaking when the pressure within a line or vessel connected to the switch exceeds a predetermined limit and. operates automatically for circuit making when the pressure within that vessel drops below a predetermined limit, the

differential between those limits being called the operating range or differential of the switch.

The switch here shown is characterized by its being provided, in addition to the usual means for bodily shitting the diil'erential or range of opening and closing pressure limits, with a means for increasing or decreasing that differential -or range, the last mentioned means being adjustable without reference to the first mentioned means.

The switch here shown is also characterized by its having an interlock type interconnection between operating parts or bell cranks o!- the switch, the interconnection being formed by a tooth on one bell crank riding in a slot in the other, the operation being such that the slotted bell crank normally causes movement of the toothed bell crank. The interconnection is characterized by the feature that it cannot possibly cause locking of the connection between the bell cranks, in any relative position of the parts.

The switch is further characterized by the provision of a snap action spring connection between operating parts or the switch, which spring functions to provide quick make-and-break; these same operating parts are provided with a means for insuring positive break in the event the spring becomes broken or injured, or fails to function properly, the positive break means becoming operable at a pressure higher than the normal or spring opening pressure of the switch, so as not to interfere with the normal spring break means of the switch.

The switch is further characterized by the fact that the snap action spring is adjustably mounted so as to provide anadjustment for increasing or decreasing the difierential or range between the pressure limits, and it will be observed that the spring adjustment also functions to adjust the opening limit of the positive break means.

' The switch is also characterized by its being provided with a contact set of novel construction, whose details will be more particularly described at a later stage of this specification.

For an understanding of the switch disclosed herein, the following specification should be read in connection with the appended drawings. In these drawings,

showing an important switch.

Fig. 1 is an elevational view or the switch with the cover removed;

. Fig. 2 is a view of the contact set per se as it from the right of Fig. l;

Fig. 3 is a top plan section view of the switch 5 with parts removed for purposes of clarity;

Fig. 4 is a detailed section view as if on the line 4-4 of Fig. 3; r

Fig. 5 is a view as it from the right of Fig. 1,

operating part or the Referring to the drawings, it will be observed that the switch therein shown comprises a base plate In and a casing II. Under the base plate, which is circular in form, but which has an apertured radially extending part I! projecting therefrom, is-a circular diaphragm ll of heavy rubber or the like, and immediately under this' diaphragm is a chambered diaphragm plate l5. The base plate, the diaphragm, and the diaphragm 5 plate are relatively secured in assembly to provide' a pressure chamber by means of the series of bolts l6. Two of the bolts are passed through the base plate and into bosses l8 oi? the casing walls lla to secure the casing to the base plate, and thus to secure the casing and the pressure chamher in assembly.

Disposed within the pressure chamber and above the diaphragm is a pressure plate (not shown) provided with an upwardly extending pin 20 engaging the horizontal arm 2! of the pressure bell crank 22, the latter being pivoted at 23 to bosses 23a formed integral with the base plate 90. The vertical arm M is hooked over and has its upper end connected to the side wall of the casing by a coiled tension spring 25 and an adjusting bolt 25 threaded through a nut 21. The last mentioned parts provide a well-known means for bodily shifting the differential or range of opening or closing pressure limits of the switch, and adjustment of these parts for shifting the range is accomplished by movement of the nut 21 on the bolt 26.

The operating mechanism of the switch, as a whole, is connected to the vertical arm 24 of the pressure bell crank 22 through the tooth and slot connection provided by a tooth 28 received within a slot 29 in the lower surface ofthe hooked upper end of the bell crank 22. The tooth 28 is integral with and projects upwardly from the hub 30 of a bell crank 3|, and this hub is secured to a threaded bolt or pin 32 which forms a fixed pivot or journal for the hub, the pin being secured to the casing wall llb.

The tooth 28 forms one arm of the bell crank 2|. The other arm, which is more properly the switching arm. comprises two parts 22-2l,-ad- Justably interconnected through the medium or the screw 25 threaded into the part II through an elongated slot 22 o! the part 24. this construction providing an adjustment means whereby the length oi. the arm 33-" may be varied to increase or decrease the differential or operating range of the switch. s V

For facilitating the 'adJustment when the-screw 35 is loosened, there'areiormed on the hub 20 two integral tapped-hole lugs "a through which is threaded an adjusting screw'llb. It will be observed that when thescrew 22b is rotated in the tapped lugs 20a, alter the screw 2| is loosened slightly, the part it may move or be'moved with respect to the part-I2, all subject to the control of the o tor.

On mmd oi arm llll is a pin 21, and a coiled tension spring 39. which forms an over center spring for the quick make-and-break or snap mechanism, has one end hooked around the pin 31. The other end of this spring is hooked around a pin 48 projecting i'rom the arm ll of a bell crank 42, the latter being iournalled at its elbow on a fixed pivot 42 in the form of a bolt threaded into the wall lib oi the casing i I. The vertical arm ll of the bell crank l2 is the switch contact arm and has at its lower end a hole through which passes a rod ll of insulating material such as fiber or the like, on the opposite ends 01 which are disposed metallic sleeves 40 which form the movable contacts or the contact mechanism, and which engage the stationary spring contacts 41 mounted on the insulating block 42 disposed against the side wall Ho 01 the casing ii. 7

'I'heblock It isheld in place by screws II which mount the contacts ll, these screws projecting through the casing wall to form externally accessible binding posts. whereby the load and line conductors may be secured in electrical and physical connection with the contacts 41, the conductor terminals and the binding screws being protected by a shield 52 secured over them and to the side wall of the casing, over the apertured extending part i2 oi the base plate.

It will be observed that when the pressure bell crank 22 rocks clockwise (Fig. l) on an increase in pressure, the bell crank 2i will rock clockwise on its iixed pivot -32 until the arm 22- and coil spring 22- move over center with respect to the pin 40 and the fixed pivot 43 of the bell crank 42.

Such movemeht causes the bell crank 42 to move for quick break, from the position shown, counterclockwise, on its fixed pivot l3 and move the contact sleeves it out 01! contact maldng position and from the stationary-contacts l'l. Conversely, a decrease in pressure will cause the switch to close, if it had been opened, the over center arrangement providing quick make movement for the parts.

The stationary contacts 41, of which there is a pair for each sleeve 46, or tour contacts in all, comprise copper spring members bent to'the formation shown in Fig. 1.

The contacts 41, at their bights, are slotted as I indicated at lid for the purposes of maintaining proper alignment of the portions of the contacts toact as a switch is opened on an increase in pressure. The relative position of the parts "-58 issuch that they will not be mutually engaged until the bell crank 42 has moved sumciently to have the sleeve 48 clear-the contact 41 a considerable distance.

In order. to provide a positive break means which is normally inoperative but which can be relied upon to cause break in the event the spring 29 becomes broken or injured or otherwise fails to function, the part 3| oi'the switching arm is provided with an extension which will engage the arm ll 0! the bell crank 42 on an instop for the switch parts when the crease in pressure to a point beyond the normal switch andthe positive break pressure isa I constant.

It will also be observed that the interlock interconnection between the bellcranks 22 and ii, provided by the tooth 28 and the slot .28 receiving it, is an eflicient, non-binding, and otherwise satisfactory two-way connection between these bell cranks, and is not ailected by cooking. of the bell cranks with respect to each other as might be the case ii. a floating pivotwere relied upon as a connection between the bell cranks 22 and 2|. Further, the engagement of-a tooth side with a slot side prevents overtravel of the switch arm 22-34. J

It will also be observed that part 24 01! the switching arm is provided with a lug 80 riding over the upper surface of the part 22, which prevents pulling oi. the switching arm as a whole when the adjusting screw is loosened; such buckling being due to the pull of spring. 29 which tends to cause movement of the part 2| clockwise around the screw 35. Buckling in the opposite direction is, or course, prevented bythe adlusting screw 38b.

Now having describedthe switch that is dis-' the scope of the monopoly claimed herein.

What 'I claim is: I

1. A pressure switch means comprising an operating bell crank, means tending to rotate the same in one direction on an increase in pressure, adjustable resilient means tending to rotate the same in the opposite direction, the two means being in opposition, a contact making bell crank, and a connector bell crank having one arm operatively connected to an armor the operating bell crank through a positive connection and having another arm operatively connected to an arm of the contact making bell crank through an adiustable resilient connection which provides an over center snap action for the contact carrying bell crank.

2. A pressure switchmean's comprising an operating bell crank, means tending to rotate the same in one direction on an increase in pressure, adjustable resilient means tending to rotate the same in the opposite direction, the two means being in opposition, a contact making bell crank, and a connector bell crank having one arm operatively connected to an arm of the operating 7 aocsnoc of the contact making bell crank through an adjustable resilient connection which provides an over center snap action for the contact carrying beii crank, the adjustment for the resilient means of the operating crank providing means for bodily shifting the difierentiai or pressure range of the switch without varying that difierentiai.

3. A pressure switch means comprising an operating bell crank, means tending to rotate the same in one direction on an increase in pressure, adjustable resilient means tending to rotate the same in the opposite direction, the two means being in opposition, a contact making bell crank, and a connector bell crank having one arm operatively connected to an arm of the operating bell crank through a positive connection and having another arm operatively connected to an arm of the contact making bell crank through an adjustable resilient connection which provides an over center snap action for the contact carrying bell crank, the adjustment for the resilient connection providing means ior varying the diflerential or pressure range of the switch without bodily shifting that difierential.

4. A pressure switch means comprising an operating bell crank, means tending to rotate the same in one direction on an increase in pressure, adjustable resilient means tending to rotate the same in the opposite direction, the two means being in opposition, a contact making beli crank, and a connector bell crank having one arm oper atively connected to an arm of the operating bell crank through a positive connection and having another arm operatively connected to an arm of the contact making bell crank through an ad justabie resiiient connection which provides an over center snap action for the contact carrying hell crank, the adjmtinent for the resilient means of the operating cralm providing means for hodiiy shifting the difierentiai or pressure range oi the switch without varying that differential, the adjustment for the resiiient connection providing means for varying the difierentiai or pressure range of the switch without bodily shifting that difierentiai. I

5. A pressure switch means comprising an operating hell crank, means tending to rotate the same in one direction on an increase in pressure, adjustable resilient means tending to rotate the same in the opposite direction, the two means heing in opposition, to contact making heii crank, and a connector bell crank having one arm operatively connected to an arm of the operating bell crank through a positive connection and having another arm operativeiy connected to an arm of the contact making he'il crank through an adjustable resilient connection which provides an over center snap action for the contact carrying hell crank, the adjustment for the resilient means oi the operating crank providing means for co-diiy shifting the ciifierentiai or pressure range of the switch without varying that differentiai, the adjustment for the resilient connection providing means for varying the difierentiai or pressure range of the switch without bodily shitting that differential, with the first mentioned one being accessible from outside the switch casing and with the second mentioned one heing accessible only from inside the switch casns.

STAImY R. DU BRIE,

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