US3340373A - Water level switch with transverse knob shaft, and the like - Google Patents

Description

E. L. BELLO Sept. 5, 1967 WATER LEVEL SWITCH WITH TRAN-SVERSE KNOB SHAFT, AND THE LIKE 3 Sheets-Sheet 1 Filed June 8, 1955 FIG-l INYENTOR EDWARD L BELLO HIS ATTORNEYS Sept. 5, 1967 E. L. BELLO 3,340,373

WATER LEVEL SWITCH WITH TRANSVERSE KNOB Filed June 8, 1965 SHAFT, AND THE LIKE 3 Sheets-Sheet 2 EDWARD L. BEL'LO BY HIS ATTORNEYS E. 1.. BELLO 3,340,373

SHAFT, AND THE LIKE Sept. 5. 1967 WATER LEVEL SWITCH WITH TRANSVERSE KNOB 5 Sheets-Sheet 3 Filed June 8, 1965 INVENTOR EDWARD L. BELLO HIS ATTORNEYS United States Patent 3,340,373 WATER LEVEL SWITCH WITH TRANSVERSE KNOB SHAFT, AND THE LIKE Edward L. Bello, Columbus, Ohio, assignor to Robertshaw Controls Company, Richmond, Va., a corporation of Delaware Filed June 8, 1965, Ser. No. 462,321 15 Claims. (Cl. 20083) This invention relates to a water level switch with a transverse knob shaft, and the like.

One of the features of this invention includes the use of an actuating shaft that is transverse to the lever construction at the top of a pressure responsive switch construction, such as a water level switch, and the like, in such a manner that the height of the switch construction is reduced very materially, in comparison with previous switch construction, in which the knob or actuating shaft has been directed in the same general direction as the actuating lever.

Another feature of this invention is the use of a transverse actuating shaft, which is transverse to the general direction of the actuating lever, and which shaft is located along the side of a spring receiving hump of the lever, in a manner to conserve the height of the switch construction.

Other features are apparent from this description, the accompanying claimed subject matter, and/or the accom panying drawings, in which:

FIGURE 1 is a diagrammatic view showing the switch construction combined with a tub of an automatic laundry washing machine.

FIGURE 2 is an enlarged end view of the switch construction shown in FIGURE 1.

FIGURE 3 is a top plan View of FIGURE 2.

FIGURE 4 is a side view of FIGURES 2 and 3.

FIGURE 5 is an enlarged cross section taken along the line 55 of FIGURE 3.

FIGURE 6 is an enlarged cross section taken along the line 66 of FIGURE 3, and showing the parts adjusted at substantially the highest fill level setting.

FIGURE 7 is a view similar to FIGURE 6, but showing the parts in manual resetting position.

FIGURE 8 is a cross section transverse to FIGURE 6, and taken along the line 8-'8 of FIGURE 3.

FIGURE 9 is a vertical view of a bracket part and the actuating shaft part taken along the line 9-9 of FIG- URE 3.

FIGURE 10 is an enlarged elevation of the resilient lock washer shown at the end of the adjusting shaft of FIGURES 2 and 3 and a cross section of the adjusting shaft in the plane of said lock washer.

FIGURE 11 is a cross section of the shaft, lock washer, and ratchet construction taken along the line 11-11 of FIGURE 10.

FIGURE 12. is an exploded perspective view of certain parts of the switch construction.

Certain words are used in this specification and in the claimed subject matter, which indicate direction, relative position, etc. However, it is to be understood that these words are used in connection with the illustrations in the drawings, and that in actual use, the parts so described may have entirely different direction, relative position, etc. Examples of these words are upper, lower, vertical and horizontal, etc.

A pressure responsive switch, such as a water level switch and the like, according to this invention, may include a casing 10, which has a general vertical axis A, FIGURES 6 and 8.

The casing 10 may contain a diaphragm 14, which sepiable pressure chamber arates easing into a variable a constant a fulcrum for one end of the snap spring 24. The other end of the snap spring 24 engages the contact carrying blade 22 near the end thereof, and causes it to snap back and forth between the stationary contacts 28 and 30. The blade 22 may have an opening, not shown, in which the snap spring 24 may rock in a well known manner.

The diaphragm 14 may be sealed at its periphery between the rims of the lower metallic casing part 31 and the upper insulative casing part 33, FIGURE 8.

The contact carrying blade 22 may have its fulcrum end secured to the upper insulative casing part 33 by a rivet 32, which may be connected to a line connecting terminal 34. The stationary contacts 28 and 30 may be likewise secured by rivets or the like, which pass through the insulative casing part 33, and are connected to terminal line connectors 36 and 38, FIGURE 12. In this manner, a power line may be connected to the connector 34, and may alternatively be connected to the connectors 36 and 38 by the operation of the switch 20.

A switch actuating means, or plunger 40, may connect the diaphragm 14 with the switch 20, and specifically with the contact carrying blade 22. The plunger 40 actuates the switch 20 in response to variable pressures in the variable pressure chamber '16.

An adjustable load means, or compression spring 42 is effective on the plunger 40 to determine which one of a plurality of variable relatively high pressures in the var- 16 will actuate the switch 20 to the upper or actuated position. In such upper position, the contact blade 22 ma 1 22 is in contact with the lower contact 28. Such pressure responsive reset means, may include the diaphragm 14, the upper flange or shoulder 44 of the plunger 40, the compression spring 42, the lower spring receiving disc '46, and the connecting rod 48 of the plunger 40 ward cars 55, FIGURE 12, to push the disc 46 to its downward position. This 48, and the upper flange 44, which push the contact carryin blade 22 to its lowermost position, even while there is V a relatively high pressure condition in the variable pressure chamber 16 due to a filled condition This power or manually resetting operation generally user by setting the selector knob 58 at a low fil or intermediate fill position. This caused the controller to fill the tub 56 to such low fill or intermediate fill position. However, the user may decide that the level to which the that a higher fill level is necessary. To obtain this higher fill level, the user must cause the switch blade 22 to be pushed down against the lower contact 28, not withstanding that the chamber 16 is under relatively high pressure, produced by the filled condition of the tub 56 which had been previously selected by the user.

To cause the movable blade 22 to be pushed down, to the reset position against the lower contact 28, under these conditions, the user can turn the selector knob 58 in a manner to cause the fingers 50 to depress the lever 54, as shown in FIGURE 7. This causes the blade 22 to be pushed down regardless of the relatively high pressure which then prevails in the variable pressure chamber 16. Thereafter, the user can turn the knob 58 to any fill position higher than the one which the user originally had selected. Such procedure causes the tub 56 to be filled to the newly selected higher fill position, which is selected by the user.

The lever, or lever means 54, may be carried by the casing above the casing transversely to the lever means 54. and transversely the axis A in a manner to be effective on the adjustable load means or spring 42 to vary or select the variable relatively high pressure at which the switch is actuated. Such lever means 54 may also be effective to operate the manually actuatable reset means, to reset the switch as heretofore described in connection with FIGURE 7. To this end, the lever means 54 may be f-ulcrumed at fulcrum 60 '11 a manner to be carried by the casing 10, above such casing 10. The fulcrum 60 may be supported on two spaced upward walls 62 of the casing 10', as shown in FIGURE 12.

The knob 58 may be secured to a rotatably adjustable shaft 64 which is carried by the casing 10, above such casing 10, and transversely to the lever or lever means 54. Such shaft 64 is effective on the lever means 54 to cause or effect the selection of the relatively high pressure, in the chamber 16, at which the switch 20 is actuated to the actuated position or upper position. The shaft 64 also may be adjusted to cause manual resetting of the switch 20, as shown in FIGURE 7, and while the pressure in the chamber 16 is at a relatively high pressure condition, as elsewhere described.

The words relatively high and relatively low are used with respect to each other, and are not dependent upon any particular datum, such as pressure per square inch, or the like. That is, the pressure responsive controller or switch of this invention may be responsive to various pressures, depending upon the use that is made of the construction.

This is illustrated, by way of example, by the use of the switch of this invention when it is connected by a tube 66 to the connector nipple 68 of the switch construction, which in turn is connected to the variable pressure chamber 16. The other end of the tube 66 may be connected to the bottom connector 70 of tub 56, so that the variable pressure chamber 16 is responsive to variable pressures which are produced, as the level of the water in the tub 56 rises, from a substantially atmospheric pressure caused by a completely empty condition of the tub, to any desired relatively high pressure, which is considered in terms of low fil intermediate fill, and high fill, of the tub or any gradual subdivisions thereof. The switch may also be considered as being responsive to relatively low pressures, such as occur when the tub 56 is empty, or with only a slight amount of water at the bottom of tub 56, but not in a condition of a completely filled tub level corresponding to some desired upper fill level. Likewise, the pressure chamber 18 in the casing 10 may be a constant pressure chamber, in which such chamber is maintained at atmospheric pressure, with tub has been filled is not sufficiently high, and.

' 72, or any other openings, which connect 4 the atmosphere imparting its pressure through the opening the chamber 18 with the atmosphere outside of the casing 10.

The shaft 64 may be provided with a pressure selecting cam 74 which may provide a gradually varying selection of relatively high pressures at which the switch 20 will be snapped up in response to a selected relatively high pressure in the chamber 16. The surface 76 of the cam 74 engages and actuates the end 78 of lever 54. For example, as shown in FIGURE 6, the cam surface 76 may be shaped to hold the lever 54 in such a position that the upper spring disc 80 of lever 54 imparts a spring load on the spring 42 to cause the switch 20 to be actuated to the upper position, when the level of the water in tub 56 reaches substantially the highest desired fill level. The shaft 64 in FIGURE 6, may then be rotated clockwise, so that a lower fill short radius position 82 of surface 82 is placed adjacent the end 78 of the lever. This permits the lever 54 to move upwardly from the full line position of FIGURE 6 to a higher position, as indicated Y then placed on the spring 42, and this in turn permits the diaphragm 14 to move upwardly under less pressure to the snap position in response to a lesser high pressure, such as produced by a low fill or intermediate fill condition of the tub, as may be selected by the user.

The lever means 54 has its fulcrum 60 on one side of they axis A, and has its adjustment actuatable lever end 78 on the other side of the axis A. The lever 54 also has an elevated lever hump or elevated portion 52 between such ends of the lever, and over the adjustable load spring means 42. The lever 54 has a relatively wide portion 84 adjacent the fulcrum 60, which wide portion is continued inthe hump 52, as is shown in FIGURES 3 and 12. This wide portion of the lever 54 is further continued downwardly by a front wall 86, FIGURE 12, which is then narrowed, so that the lever end portion 78 is relatively narrow, so that the fingers 50, can straddle the narrow end 78, as is evident from FIGURES 2, 3 and 12. Thus the fingers 50 maybe rotated clockwise, in FIGURE 6, to their dotted line position, shown in such FIGURE 6.

The ears 55, FIGURE 12, positively push the disc 46 down to reset the switch 20 when the shaft 64 is moved to the position of FIGURE 7.

As shown in FIGURE 6, the shaft 64 is over the actuatable end 78 of the lever-54, and also is along the side of the elevated portion or hump 52, when the lever is in the position of FIGURE 6. This, in effect, countersinks the shaft 64 below the highest portion 52 of the lever 54. It is therefore possible to reduce the height of the switch construction, by, placing the shaft 64 transversely to the lever and along the side of the hump 52.

If desired, the shaft 64 may be provided with a rotatable ratchet, or ratchet wheel 88, FIGURES 2, 3, 5 and 12. This wheel 88 may be provided with a serrated or fluted surface 90, which has teeth to provide frictional retention ofa selected position of the shaft 64. A spring detent 92 may be provided to engage the ratchet 88, and the teeth 90 thereof, to provide such retention of a selected position of the shaft 64. The spring detent 92 may be biased rightwardly in FIGURES 5 and 12 and may be provided with a ratchet engaging V shaped bend 94 to engage the teeth 90.

The ratchet wheel 90 may also be provided with a smooth surfaced notch 96, FIGURES 5 and 12, which is effective during the resetting action of the shaft 64, so.

that there is no frictional'retention in this notch 96 during the manual resetting operation. The spring detent 92 is loosely engaged in the notch 96 during the manual resetting of the switch, while the knob 58 and shaft 64 are being turned from a high fill position 98 of knob 58, FIG- URE 4, to a reset position with the reset indicator 100 of FIGURE 4 moved leftwardly. When a resetting action is produced, such as with a movement of the parts from their positions in FIGURE 6 to their position in FIG- dotted lines in FIGURE 6. A reduced spring load is I URE 7, with the shaft 64 moving counterclockwise, the detent 92 does not produce any frictional action on the ratchet 88, while the detent part 94 is in the notch 96, FIGURE 5.

When the knob 58 is released, after having been turned to the reset position, the shaft 64 can be rotated automatically back to the position of FIGURE 6, by the action of the spring 42 acting through the hump 52 on the fingers 50, without any frictional resistance from the detent 92. However, when the lever 54 is pushed upwardly or snapped upwardly by the spring 42 from the position of FIGURE 7 to that of FIGURE 6, the lower end of the notch 96 will engage the V shaped portion 94 as shown in FIGURE 5. This will arrest the shaft 64 in this position. This will automatically position the knob 58 and shaft 64 in the highest fill position after the resetting operation. The user may then turn the knob and shaft to some other position, to select intermediate fill, low fill and then the teeth 90 of the ratchet 90 will be engaged by detent part 94 to hold the shaft and knob in such selected position.

The shaft 64 may be mounted on a bracket construction 102, FIGURES 2, 3 and 9-12, which includes vertical end walls 104 and 106. The vertical wall 104 may be provided with a slanting slot 108, which terminates in acircular hole 110, FIGURE 9, which is substantially of the same size as the widest part of the metallic portion of the shaft 64 which is illustrated in FIGURE 12. The shaft 64 may be provided with a circular groove 112, FIGURES 3 and 12. This groove 112 may slide down the slot 108 while the shaft 64 is being installed in the bracket construction. The metallic part of shaft 64 may be substantially of constant diameter, except at the groove 12, at one end, and another groove 14, FIGURE 11, at the other end of the shaft. The bracket 106 has an opening 116, FIGURE 12, which is of a diameter to receive the thickest part of the metallic part of the shaft 64. During installation of the shaft 64, the shaft is placed slightly downward, in FIG- URE 3, so that the groove 112 can pass into and through the slot 108, FIGURE 9, and so that the end 118 of the shaft may be held ready to pass upwardly, in FIGURE 11, through the opening 116, in bracket 106, after the groove 112 has been moved down to place a shaft in the opening 110 of FIGURE 9. Thereafter, the shaft is moved upwardly, in FIGURES 3 and 11, so that the end 118 of the shaft protrudes from the bracket wall 106, FIGURE 11. Thereafter, an outwardly spreadable lock washer 120 with teeth as illustrated in FIGURE 10, is snapped so the teeth enter into the groove 114, and lock shaft 64 in place. The ratchet wheel 88, FIGURE 11, may be spaced at distance from the groove 114 a distance substantially equal to the thickness of the bracket or end wall 106. When the lock washer 120 has been snapped into the groove 114, the shaft 64 is longitudinally locked against substantial longitudinal movement by the ratchet wheel 88 on one side of wall 106 and by lock washer 120 on the other side of wall 106.

The ratchet wheel 88, the cam 74, and the fingers 50 and the connecting parts thereof which are illustrated as one body in FIGURE 12, may be made of any suitable plastic material, which may surround and be fixed to the metallic main body 64 of the shaft, which is separately illustrated in FIGURE 12. If desired, suitable frictional indentations, knurled portions and the like, not shown, may be provided on the metallic part of the shaft 64, FIGURE 12, to insure that such plastic parts 50, 74, 88, etc., are fixed to such metallic part. Suitable plastic materials may be obtained from manufacturers of plastic materials, as is common practice.

If necessary for the disclosure of details of the switch 20 and certain other parts, reference is made to the application of William E. Rhodes and Werner R. Bauer, Ser. No. 189,050, filed Apr. 20, 1962, for Pressure Responsive Switch.

A new, useful and unobvious pressure responsive switch construction has thus been provided by this invention.

While the form of the invention now preferred has been disclosed as required by the statutes, other forms may be used, all coming within the scope of the claims which follow.

What is claimed is: 1. In combination: a casing having a vertical axis; a diaphragm in said casing separating said easing into a variable pressure chamber and a constant pressure chamber; a switch in said casing; switch actuating means connecting said diaphragm to said switch to actuate said switch in response to variable pressures in said variable pressure chamber; adjustable load means engaging said actuating means to determine a variable relatively high pressure in said variable pressure chamber at which said switch is actuated to actuated position from an unactuated set position; pressure responsive reset means to determine a reset relatively low pressure in said variable pressure chamber at which said switch is reset to said unactuated set position; manually actuable reset means to reset said switch to said unactuated set position while said variable pressure chamber is at a relatively high pressure condition; lever means carried by said casing and above said casing transversely to said axis and engaging said adjustable load means to vary said variable relatively high pressure at which said switch is actuated and engaging said manually actuable reset means to reset said switch;

a rotatably adjustable shaft means carried by said cas. ing and above said casing transversely to said lever means and engaging said selection of said relatively high pressure at which said switch is actuated and to cause said manuel resetting of switch.

2. A combination according to claim 1 in which said lever means has a fulcrum supported lever end on one side of said axis, an adjustment actuable lever end on the other side of said axis, an adjustable load and a manual resetting elevated lever portion between said ends and over said adjustable load means.

3. A combination according to claim 2 in which said shaft means is over the actuable end and along the side of said elevated lever portion.

4. A combination according to claim 3 in which said shaft means has rotatable cam means engaging said lever means to effect selection of said variable relatively high pressure.

5. A combination according to claim 3 in which said shaft means has a rotatable finger means engaging said lever means to effect manual resetting of said switch.

- 6. A combination according to claim 3 in which said shaft means has a rotatable ratchet to provide frictional retention of a selected position of said shaft means.

7. A combination according to claim 6 in which a spring detent is provided to engage said ratchet to provide said retention of a selected position of said shaft means.

8. In combination:

a casing having a vertical axis;

a diaphragm in said casing separating said easing into a variable pressure chamber and a constant pressure chamber;

a switch in said casing;

switch actuating means connecting said diaphragm to said switch to actuate said switch in response to variable pressures in said variable pressure chamber;

adjustable load means engaging said actuating means to determine a variable relatively high pressure in lever means to cause said said variable pressure chamber at which said switch is actuated to actuated position from an unactuated set position;

pressure responsive reset means to determine a reset relatively low pressure in said variable pressure chamber at which said switch is reset to said unactuated set position;

manually actuatable reset means to reset said switch to said unactuated set position while said variable pressure chamber is at a relatively high pressure condition;

lever means carried by said casing and above said casing transversely to said axis and engaging said adjustable load means to vary said variable relatively high pressure at which said switch is actuated and engaging said manually actuatable reset means to reset said switch;

a rotatably adjustable shaft means carried by said casing and above said casing transversely to said lever means and engaging said lever means to cause said selection of'said relatively high pressure at which said switch is actuated and to cause said manual resetting of switch and in which said lever means has a fulcrum supported lever end on one side of said axis, an adjustment actuatable lever end on the other side of said axis, an adjustable load and a manual resetting elevated lever portion between said ends and over said adjustable load means and in which said shaft means is over the actuatable end and along the side of said elevated lever portion and in which said shaft means has a rotatable ratchet to provide frictional retention of a selected position of said shaft means and in which a spring detent is provided to engage said ratchet to provide said retention of a selected position of said shaft means in which said ratchet has a manual resetting notch in which said spring detent is loosely engaged during manual resetting of said switch.

9. A combination according to claim 8 in which one end of said manual resetting notch is engaged by said spring detent to hold on said shaft means against said elevated lever portion after a manual resetting operation.

a rotatable finger resetting means 10. In combination:

a casing having a vertical axis;

a diaphragm in said casing separating said casing into a variable pressure chamber and a constant pressure chamber;

a switch in said casing;

switch actuating means connecting said diaphragm to said switch to actuate said switch in response to variable pressures in said variable pressure chamber;

adjustable load means engaging said actuating means to determine a variable relatively high pressure in said variable pressure chamber at which said switch is actuated to actuated position from an unactuated set position;

pressure responsive-reset means to determine a reset relatively low pressure in said variable pressure chamber at which said switch is reset to said unactuated set position;

power actuatable reset means to reset said switch to said unactuated set position while said variable pressure chamber is at a relatively high pressure condition;

lever means carried bysaid casing and above said casing transversely to said axis and engaging said adjustable load means to vary said variable relatively high pressure at which said switch is actuated and engaging said power actuated reset means to reset said switch;

a rotatably adjustable shaft mean-s carried by said casing and above said casing transversely to said lever means and engaging said lever means to cause said selection of, Said relatively high pressure at which said switch is actuate-d and to cause said power resetting of switch.

11. In combination:

a casing having a generally fiat top casing portion;

a switch in said casing;

diaphragm means in said casing with a movable diaphragm portion movable in response to variable pressure differentials on opposite sides of said casing and with a switch operating portion actuating said switch to an actuated position in response to movement of said movable diaphragm portion;

adjustable load means engaging said diaphragm means to determine a pressure differential at which said diaphragm portion actuates said switch to said actuated position;

a generally horizontal lever means carried by said top casing portion and being movable to engage said adjustable load means to vary the pressure differential at which said diaphragm portion actuates said switch means to said actuated position;

and a shaft means transverse to said lever means and moving said lever means to cause said lever means to vary said adjustable load means to vary said lastnamed pressure differential.

12. A combination according to claim 11 in which said lever means has a high central portion which has means engaging said adjustable load means, and in which said shaftmeans is below said high central portion.

13. A combination according to claim 12 in which said lever means has an actuatable end means which is below said high central portion and in which said shaft means is above said end means and below said portion.

high central 14. In combination:

a casing having a generally flat top casing portion;

a switch in said casing;

diaphragm means in said casing with a movable diaphragm portion movable in response to variable pressure differentials on opposite sides of said casing and with a switch operating portion actuating said switch to an actuated position in response to movement of saidmovable diaphragm portion;

adjustable load means engaging said diaphragm means to determine a pressure differential at which said diaphragm portion actuates said switch to said actuated position; a generally horizontal lever means carried by said top casing portion and being movable to engage said adjustable load means to vary the pressure differential at which said diaphragm portion actuates said switch means to said actuated position;

and a shaft means transverse to said lever means and moving said lever means to cause said lever means to vary said adjustable load means to vary said lastna'med pressure differential and in which said lever means has a high central portion which has means engaging said adjustable load means, and in which said shaft means is below said high central portion and in which said lever means has an actuatable end means which is below said high central portion and in which said shaft means is above said end means and below said high central portion and in which said top casing portion has a bracket means having a horizontal base and opposite first and second end vertical walls, said first wall having a slanting slot extending from an upper portion of said first wall to its lower slot end, a lower portion of said first wall, said lower slot end being connected to a first shaft receiving opening, said second wall having a second shaft receiving opening aligned with said first shaft receiving opening;

said shaft means having a groove slidable in said slot, said shaft means being longitudinally slidable in said openings after said grooverhas been moved to said lower slot end with a shaft means end extending through and out of said second opening, and havwith a shaft end extending through and out of said ing shaft locking means engaging said second wall second opening; and locking said shaft means against longitudinal and shaft locking means engaging said second wall and movement. locking said shaft against longitudinal movement. 15. In combination: 5 bracket means having a horizontal base and opposite References Cited first and second end vertical walls, said first wall UNITED STATES PATENTS having a slanting slot extending from an upper por- 3,065,320 11/1962 Cobean tion of said first wall to its lower slot end, a lower portion of said first wall, said lower slot end being 10 gauer 2g0 83 connected to a first shaft receiving opening, said 3249712 5/1966 S31 5 8:2;

second wall having a second shaft receiving opening aligned with said first shaft receiving opening; p

a shaft having a groove slidable in said slot, said shaft BERNARD GILHEANY Pnmary Exammer' being longitudinally slidable in' said openings after 15 G. MAIER, H. B. GILSON, Assistant Examiners. said groove has been moved to said lower slot end

Claims (1)

1. IN COMBINATION: A CASING HAVING A VERTICAL AXIS; A DIAPHRAGM IN SAID CASING SEPARATING SAID CASING INTO A VARIABLE PRESSURE CHAMBER AND A CONSTANT PRESSURE CHAMBER; A SWITCH IN SAID CASING; SWITCH ACTUATING MEANS CONNECTING SAID DIAPHRAGM TO SAID SWITCH TO ACTUATE SAID SWITCH IN RESPONSE TO VARIABLE PRESSURES IN SAID VARIABLE PRESSURE CHAMBER; ADJUSTABLE LOAD MEANS ENGAGING SAID ACTUATING MEANS TO DETERMINE A VARIABLE RELATIVELY HIGH PRESSURE IN SAID VARIABLE PRESSURE CHAMBER AT WHICH SAID SWITCH IS ACTUATED TO ACTUATED POSITION FROM AN UNACTUATED SET POSITION; PRESSURE RESPONSIVE RESET MEANS TO DETERMINE A RESET RELATIVELY LOW PRESSURE IN SAID VARIABLE PRESSURE CHAMBER AT WHICH SAID SWITCH IS RESET TO SAID UNACTUATED SET POSITION; MANUALLY ACTUABLE RESET MEANS TO RESET SAID SWITCH TO SAID UNACTUATED SET POSITION WHILE SAID VARIABLE PRESSURE CHAMBER IS AT A RELATIVELY HIGH PRESSURE CONDITION; LEVER MEANS CARRIED BY SAID CASING AND ABOVE SAID CASING TRANSVERSELY TO SAID AXIS AND ENGAGING SAID ADJUSTABLE LOAD MEANS TO VARY SAID VARIABLE RELATIVELY HIGH PRESSURE AT WHICH SAID SWITCH IS ACTUATED AND ENGAGING SAID MANUALLY ACTUABLE RESET MEANS TO RESET SAID SWITCH; A ROTATABLY ADJUSTABLE SHAFT MEANS CARRIED BY SAID CASING AND ABOVE SAID CASING TRANSVERSELY TO SAID LEVER MEANS AND ENGAGING SAID LEVER MEANS TO CAUSE SAID SELECTION OF SAID RELATIVELY HIGH PRESSURE AT WHICH SAID SWITCH IS ACTUATED AND TO CAUSE SAID MANUEL RESETTING OF SWITCH.

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