US2454647A

US2454647A - Pressure switch

Info

Publication number: US2454647A
Application number: US534189A
Authority: US
Inventors: Willis H Gille
Original assignee: Honeywell Inc
Current assignee: Honeywell Inc
Priority date: 1944-05-05
Filing date: 1944-05-05
Publication date: 1948-11-23
Anticipated expiration: 1965-11-23

Description

Nov. 23, 1948. w GlLLE I 2,454,647

PRES SURE SWITCH Filed lay 5, 1944 2 Sheets-Sheet 1 E. I 63 x 60 66 55 if I" .77 40 46 v :f '93 1M H 70 I l Tin Lr:: Tl l I I 7? l I I l n Saventor WILL/5 GILLE Nov. 23, 1948. w. H. GILLE 7 PRESSURE SWITCH Filed May 5, 1944 2 Sheets-Sheet 2 Snoentor WILL/5 H. (HALE PatentedNov. 23, 1948 raassmm swrron Willis 11. Gille, St. Paul, Minn, assignor to Minncapolis-Honeywell Regulator Company, Minneapolis, Mlnn., a corporation of Delaware Application May 5, 144, serial No. 534,189

(01. zoo-81.5)

24 Claims.

This invention relates to a condition responsive switch and more particularly to a fuel pressure switch which is adapted to be responsive to fuel pressure in a fuel line of an aircraft.

The pressure switch of this invention may be utilized in the fuel system of an aircraft, and which switch is actuated at predetermined fuel pressures by the fuel in a line of the fuel system.

When the pressure switch is moved to closed position by a predetermined fuel pressure in a fuel line. a relay means is energized for opening valve means so that fuel can be supplied to different heaters in an aircraft such as the cabin or cockpit heaters. If the pressure falls below a certain value in the fuel line, the fuel pressure switch moves to open position and the relay mechanism actuates the valve to closed position, thus shutting off the flow of fuel to the heaters. A break in the fuel line or a clogging in the fuel line would cause a fall in pressure below a predetermined or safe value and the fuel pressure switch would be opened. When the pressure of the fuel in the fuel line is below a certain value, the heaters would be damaged if fuel were fed to the heaters.

=It is the purpose of this inventioin to utilize the novel switch of this invention in a fuel pressure system of an aircraft, which permits the feeding of fuel to the heaters at a. predetermined high pressure value, and which prevents the feeding of fuel to the heaters when the pressure in the fuel line falls below a predetermined low value.

It is an object of this invention to provide a pressure switch in which the pressure sensing element is so arranged that there is a double seal formed between the fuel in the sensing element and the electrical contacts of the switch means to provide maximum safety of operation.

It is another object of this invention to provide a chamber surrounding a sensing bellows in which atmospheric or a pressure other than atmospheric pressure may be employed as a reference pressure in relation to the pressure employed in the sensing bellows.

It is another object of this invention to provide a first bellows for cooperating with a sealed chamber and the force resulting from pressure in a second bellows spaced in the chamber may be transmitted from said second bellows through the first bellows for actuating switching means on the outside of said chamber.

It is another object of this invention to provide a lever assembly which is associated with a pair of crossed reeds so that the lever assembly has a movement in only one plane in order that the contacts of the switch remain in proper alignment for efficient and accurate operation of the switch. i

It is still another object of this invention to provide a sensing bellows spaced in a sealed chamber so that differential pressures may be employed in the operation of the switching device.

It is still another object of this invention to provide a flexible means for sealing an outlet in a chamber so that rocking movement may be transmitted from the chamber.

It is another object of this invention to provide a lever assembly having rocking movement for transmitting motion from a sensing element so that a control device is quickly actuated.

It is a still further object of this invention to utilize two pair of crossed reeds in a pressure switch device in order that a flexible and frictionless movement may be maintained between the sensing bellows and the switching means.

It is another object of this invention to provide a switch which is arranged to cut in on increasin fuel pressure and to cut out on decreasing fuel pressure.

It is a still further object of the invention to provide two pair of crossed reeds associated with a seal-off bellows for a chamber so that the sealoff bellows remains stable with changes in pressure in the chamber which houses the sensing bellows.

Other and further objects may become evident from the following detailed description of the device.

For a complete understanding of my invention, reference should be made to the accompanying drawings, in which Figure 1 is an elevational view of the fuel pressure switch, the casing being in section and parts being broken away;

Figure 2 is a vertical sectional view of the fuel pressure switch, parts being broken away;

Figure 3 is a sectional view taken on line 3-3 of Figure 2, in the direction of the arrows;

Figure 4 is an elevational view of the right side of Figure 1, parts being broken away. Referring in detail to the fuel pressure switch, in is a base member for housing the pressure sensing element of this switch and comprises a lower portion l2 and a cap portion I 4 having an enlarged section l5. Cap portion I4 is sealed to the lower portion 12 and forms a chamber IT. The base member I0 is preferably circular in shape.

The lower portion [2 of the base member Ill contains-a flanged member it! having a threaded passageway 20 formed therein which communicates with the interior of a sensing bellows 22 located in the chamber l1 formed by the portions l2 and 14 when in assembled relationship. The sensing bellows 22 is supported on and secured to the flanged sleeve member l8. Passageway 23 is adapted to 'be connected to a fuel line, not shown, of an aircraft, so that fuel pressure may be communicated to the sensing bellows 22. The lower portion [2 of the base member in also contains a second flanged member 24 having a threaded passageway 26 formed therein for communication with the chamber The passage 24 is adapted to be connected to some pressure source, not shown, so that pressure may be supplied to the chamber i1 surrounding the sensing bellows 22. The pressure usually supplied to the chamber 11 is air pressure but other fluids may be employed such as fuel pressure or the like. The bellows 22 extends into the enlarged housing portion IS in the cap portion l4 and a plunger 28 of the bellows 22 engages a notched portion 30 in a lever member 32.

Portion 34 of the lever 32 is substantially arouate in shape (see Figure 3). There is an angular downwardly extending portion 35 at each end of the arcuate portion 34. A substantially right angular arm 36 extends from each of the down-'- wardly extending portions 35 of the lever 32. The arms 36 merge into a, porition 38 adjacent a post 413. The merged portion 38 of the lever 32 is secured to the post 48 which is associated with a' seal-ofl bellows 42.

There is an opening in the cap portion M of the base member I!) communicating with the chamber l1, and the bellows 42 seals this opening in chamber l1 and separates chamber ill from the electrical contacts of the switch means 64 spaced above the cap portion i l. The bellows 42 is open at its bottom for communicating with the chamber l1. The bellows 42 is positioned on the top of cap member i4 to the right of the bellows 22 as shown in Figure 2 or" the drawings. Post Ail has a flanged portion 42 for securing a lever 48 to the top of the seal-oil bellows 42. A plate 56 is carried between the lever 43 and the top of the bellows 42.

The left side of the lever 48 looking at Figure 2 has an arm of insulation material 52 secured thereto by rivet means. A contact arm h t is secured by rivet means or the like to the insulation arm 52. An adjustable contact element 56 having a contact 58 at its upper end is screw threaded into an aperture in the contact arm til. A con tact arm 60 is spaced above the contact arm 54 and carries a mating contact 62 of the switch 64.

When there is a change in the fuel pressure in the sensing bellows 22, the lever 32, the post 42 of the seal-off bellows 42; lever 48, insulation arm 52, and contact arm 54 are actuated by the bellows 22 for opening and closing the switch 65 depending upon whether there is a fall or rise in the pressure in the sensing bellows 22.

There is an adjustable range spring 66 attached to the plate 50. This range spring normally biases the lever 48 in a counterclockwise direction.

The range spring 66 serves as an independent means for adjusting the values ofthe condition at which the switch 64 may be opened and closed.

Reeds 68 and are associated with the plate 50 on the left side of. thebellow 42 (see Figure 4). Each of the reeds 68 and iii is formed of a flat flexible spring-like material. The reed 68 is secured at its lower end to a block member 12 and has its other end secured to the under side of the plate 50. The reed 1B is likewise secured to the block member 12 at its lower end, while its uppergend is secured to the under side of plate 58. The reed 10 is spaced slightly to the rear of the reed B8. The reeds 53 and 10 are crossed at substantially right angles between their points of attachment and are arranged edgewlse at the point of crossing. I

Reeds

14 and 18 are placed on the right side of the seal-cit bellows 42 (see Figure 4) and have their upper and lower ends respectively secured to the plate 50 and a block member 13. The reeds 14 and 1B are of flat flexible spring-like v material, and they are structurally arranged with respect to each other as are the reeds B8 and 10.

The reeds 681il, and 14-16 function as flexassembly 33 pivots substantially about an axis determined by the intersections of the pair of crossed reeds. The crossed reeds 6810, 14-16 are secured between the plate 50 and blocks 12 and 13 respectively in a taut condition. The crossed reeds being connected in a taut condition prevents upward and downward movement of the lever assembly, and also prevents lateral movement thereof, but allows a rocking movement of the lever assembly 33. This movement of the lever assembly in one plane maintains the contacts of the switch in proper alignment for efficient operation of the switch.

The operation of the switch in one application, as in an aircraft, is as follows: when fuel pressure at a predetermined value communicates through a pipe, not shown, and enters the passageway 20 at the bottom of the member ill into the sensing bellows 22, the sensing bellows 22 is actuated upwardly and the plunger 28 thereof engages the lever 32 and force is transmitted from the lever 32 to the post 40 of the seal-01f bellows 42. The force of the pressure is then transmitted from the post 40 to lever 43. The lever assembly 33 comprising the lever 32, post 40, lever 43, and arms 52 and 54 all move as one element and are pivoted substantially about an axis determined by the intersection of the pairs of crossed reeds 681il and lid-1i) and the central transverse portion 01' bellows s2.

The bellows 22 ,actuates the left end of the lever 32 upwardly as seen in Figure 2. The lower end.

of the post 40 is moved to the left by the upward movement of the lever 32 while the upper end of the post 40 is moved to the right by the same motion, the post 40 pivoting substantially about an axis determined by the intersection of the pair of crossed reeds 6810, and 14-16 at the central transverse portion of bellows 42. This pivotal movement of the post 40 causes the left end of the lever 48 to move upwardly carrying the .connected arms 52 and 54 and the associated contact 58 so that the contact 58 engages the mating contact 62 on the arm 60, thereby closing the switch 64. This same pivotal movement results in a downward movement of the right end of the lever 48 and the plate 50 against the upward bias of the range spring 66.

The crossed reeds 68-10 and 14-16 are fastened at their upper endsto the plate 53 and at their lower ends to the blocks 12 and 13 respec- 80 in an upwardly direction but upon actuation of the lever 82 upwardly by pressure acting on the inside of sensing bellows 22, the right end of lever 48 as seen in Figure 2 is moved downwardly but the force transmitted from bellows 22 through lever 82 and post 40 to the lever 48 must over- ,.come the upwardly biasing force of the spring 88 before the switch 84 is actuated to closed position. The pressure in the sensing bellows 22 must also overcome the reference pressure in the chamber l1 before the switch 84 is actuated to closed position,

When the fuel pressure in the fuel line leadin to the sensing bellows 22 falls below a predetermined value, the pressure in the sensing bellows 22 likewise falls. As a result, the end of the lever 82 adjacent the plunger 28 of the sensing bellows 22 is moved downwardly. The lever 82 now moves the lower end of the post 40 to the right as seen in Figure 2 while the upper end of the post 40 is moved to the left. The post.40 is caused to rock because it is pivoted on the axis formed by the intersection of the pairs of crossed reeds 8810 and 14-18. This rocking movement of the post 40 moves the right end of the lever 48 upwardly and the left end of the lever 48 and its associated contact arm54 downwardly; and arm 54 carries contact 88 from engagement with contact 82 on arm 80 and opens switch 84. The force or the biasing spring 88 which is upwardly on the rightend of the lever 48 aids in pulling the opposite end of the lever 48 in a downwardly direction.

The positioning of the sensing element or bellows 22 in the chamber II of the member i necessitates means for transmitting the force acting on the sensing bellows 22 for operating the switch 84 spaced outside the chamber IT. The opening in the top of the cap portion I4 is sealed by the bellows 42 and its integral post element 40 extends into the chamber IT. The motion or force from the sensing bellows 22 is transmitted by lever 82 to the post 40 of the seal-off bellows 42. The movement of the post 40' actuates the lever 48 attached thereto and the associated arms 82 and 84. The bellows 42 which seals the chamber I! being flexible permits motion to be transmitted from the sensing bellows 22 through the post 40 of the seal-off bellows 42 to the lever 48 so that the switch 84 may be actuated as is required in its association with the fuel system of an aircraft. The flexible seal-off bellows 42 being held downwardly by the crossed reeds 88-40 and 'I4l8 spaced on diametrically opposed sides thereof, permits the central transverse portion of the seal-off bellows 42 to be pivoted by the lever assembly 88 when actuated by the sensing bellows 22. That is, the lever assembly 88, when actuated by the sensing bellows 22, flexes the right and left sides of the bellows 42, as seen in Figure 2, upwardly and downwardly, respectively, and also downwardly and upwardly, respectively, thus pivoting the lever assembly 33 substantially about an axis passing through the central transverse portion of the bellows 42. The lever assembly 88 when actuated by the sensing beilows'22 flexes the upper ends of the reeds and I8 upwardly and downwardly respectively,

and also flexes the upper ends of reeds 88 and 14 6 downwardly and upwardly respectively, and the lever assembly 88 thus pivots about the axis determined by the intersection of the crossed reeds 88-10 and 14'i8. I

The bellows 42 also functions to seal the chamber l1 and different pressures may be supplied to the chamber H for contacting the outside of the sensing bellows 22 spaced in the chamber so that differential pressures may be employed in the actuation of the switch device.

The spacing of the sensing element 22 in the chamber l1 provides a double seal means between the fuel in the sensing bellows 2,2 and the switch contacts of this device. The sensing bellows 22 acts as a first seal means for the fuel employed as the pressure actuating force, and if the bellows 22 should rupture, the fuel would then be discharged into the chamber l1, and the sealed chamber i'i would serve as a second seal means for sealing the fuel from the electrical contacts of the switch 84.

It will be readily apparent that in accordance with my invention, many changes may be made in the detailed construction and arrangement of the elements. It may be possible to use other means for actuating the sensing bellows other than fuel pressure and for actuating the switch means in this light. The constructions set forth in this application are for illustrative purposes only, and the invent-ion is accordingly defined and limited only by the appended claims.

I claim'as my invention:

1. In a switch of the class described comprising in combination, switching means, condition responsive means controlling the operation of the switching means, a sealed housing providing a chamber surrounding the condition responsive means so that differential pressures may be employed for actuating the switching means, the housing having an opening, a bellows means for sealing the opening in the housing, a lever assembly, and crossed reed pivot means connected with the lever assembly, the lever assembly connected to the bellows through the opening in the housing,

the resconsive means responsive to a change in the condition for causing rotation of the lever assembly about the crossed reed pivot means and the bellows for actuating said switching means.

2. In a switch of the class described comprising in combination, switching means, condition responsive means for controlling the operation of the switching means, a housing comprising a chamber for surrounding the condition responsive means, the housing having an outlet, flexible means sealing the outlet in the housing, a lever assembly associated with the flexible sealing means, a plurality of crossed reed pivots connected with the lever assembly, the condition responsive means causing rotation of the lever assembly about the reed pivot means and the flexible sealing means between a predetermined range of values of the condition for opening and closing the switching means, and means for varying the I vaues of the condition at which the switching means is opened and closed by the condition responsive means.

3. In a device of the class described comprising in combination, a device to be actuated, a condition responsive means for controlling the operation of said device, resilient means opposing said condition responsive means, a lever assembly, and two pair of crossed reeds connected with the lever assembly, the condition responsive means upon a change in the condition causing rotation of the lever assembly substantially about an axis deter- :7 r mined y the intersection of the two pair or crossed reeds for actuating said device.

4. In a switch of the class described comprisin in combination. switching means, a condition responsive means for controlling the operation oi the switching means, a housing forming a sealed chamber which encloses the condition responsive means, the housing having an outlet means, a flexible means sealing the opening in the housing, a lever assembly exmnding through the outlet means of the housing and associated with the hero ible sealing means, and reed pivot means connect= ed with the lever assembly, the condition respoh sive means causing rotation of the lever assembly about the reed pivot means and the flexible sealing means between a predetermined range of values of the condition for opening and closing the switching means.

5. In a switch of the class described comprising in combination, switching means, a condition responsive means for controlling the operation of the switching means, a housing forming a sealed chamber which encloses the condition responsive means, the housing having an outlet means, flexible means sealing the outlet means in the housing, a lever assembly extending through the outlet means of the housing and associated with the flexible sealing means, and two pair of spaced apart crossed reeds connected with the lever assembly, the-condition responsive means causing rotation of the lever assembly substantially about an axis determined by the intersection of the two pair of cross reeds between a predetermined range of values of the condition for opening and closing the switching means.

6. in a device of the class described, comprising in combination, control means, a condition. nesponsive means for controlling the operation of the control means, a chamber enclosing the con dition responsive means, a seal-oil bellows asso== elated with the chamber, a lever assembly asso ciated with the seal-off bellows, a plurality oi spaced apart crossed. reeds connected the said lever assembly, the condition responsive means responsive to a change in the condition causing rotation of the lever assembly about the plurality of crossed reeds and the seal-oil bellows for actuating the control means,

7. in a device of the class described, comprising in combination, control means, condition respon= sive mean for controlling the operation of the control means, a housing forming a chamber en= closing the condition responsive means and separating the condition responsive means from the control means, a lever assembly, and two pair of spaced apart crossed reeds connected with said lever assembly, the condition responsive means responsive to a change in the condition for cansing rotation of the lever assembly about the two pair of crossed reeds for actuating the control means.

d. In control device, comprising in combination, control means, a condition responsive means for controlling the operation of the control means, a housing forming a chamber for enclosing the condition responsive means, the housing having outlet means, flexible means sealing the outlet means in the housing, a lever assembly associ-- ated with the flexible sealing means, and two pair of spaced apart crossed reeds connected with the lever assembly, the condition responsive means responsive to a change in the condition for causing rotation of the lever assembly about the two pair of spaced apart crossed reeds and the flexible sealing means for actuating the con- Eli (dill trol means.

9. In a switch of the class described comprising in combination, switching means, a condition responsive means for controlling the operation or the switching means, a housing forming a sealed chamber for enclosing the condition responsive means and separating the condition responsive means from the switching means, the housing having outlet means, a bellows sealing the outlet means, an actuator assembly comprising a first arm in the sealed chamber, a second. arm spaced outside the chamber, and a portion con necting the first and second arms, the actuator assembly associated with the bellows, a plurality of spaced apart crossed reeds connected with the actuator assembly, the condition responsive means responsive to a change in the condition for cans ing rotation of the actuator assembly about the plurality of crossed reeds for actuating the switching means.

iii. In a switch of the class described comprls ing in combination, switching means, fuel pressure responsive means for controlling the oper ation of the switching means, a housing conn prising a chamber for sealing the fuel pressure responsive means from the switching means, the housing having outlet means, flexible bellows sealing the outlet means in the housing, the fuel pressure responsive means being a first seal means for the fuel pressure, the sealed chamber adapted to act as a second seal means for the fuel pres= sure, and rocking means comprising the deioible bellows means and two pair of spaced apart crossed reeds positioned adjacent the bellows means, the fuel pressure responsive means responsive to a change in the fuel pressure for moving the rocking means about an axis determined by the intersection or the two pair of crossed reeds for actuating the switching means.

ll. In a switch of the class described comprising in combination, a switching means, a fuel pressure responsive means for controlling the operation of the switching means, a housing forming a sealed chamber for separating the fuel pres= sure responsive means from the switching means, the housing having an opening, bellows means sealing the opening the fuel pressure responsive means being a first seal means for the fuel pres sure, the sealed chamber adapted to act as a second seal means for the iucl pressure, and lever means connecting the pressure responsive means with the switching means, the lever means connected with the bellows means, pivot means com 1 prising two pair of crossed reeds positioned in diametrically opposed. relation on the outside of the bellows and connected with the lever means, the axis of the pivot means passing through the central transverse portion of the bellows, the pressure responsive means responsive to a change in the fuel pressure for moving the lever means for actuating the switching means.

l2. In a device of the class described comprising in combination, control means, condition re sponsive means controlling the operation of the control means, housing providing e. sealed chamber for enclosing the responsive means and separating the responsive means from the control means, the housing having an opening, bellows means sealing the opening in the housing, actuator means connecting the condition responslve means with the bellows means, and a. plurality of spaced apart crossed reeds connected with said actuator means in such a manner for restraining upward movement of the bellows means, the condition responsive means responsive to a change in the condition for causing rotation of the actuator means about the plurality of spaced apart crossed reeds and the bellows means for actuating the control means.

13. In a device of the class described, comprising in combination, control means, a pressurev responsive means for controlling the operation of the control means, a housing forming a chamber enclosing the pressure responsive means and separating the pressure responsive means from the control means, the sealed housing having a reference pressure for regulating the operation of the pressure responsive means the housing having outlet means, flexible means sealing the outlet means in the housing, a lever assembly associated with the flexible sealing means, and two pair of spaced apart crossed reeds arranged ad- .lacent the sealing means and connected to the lever assembly the condition. responsive means responsive to a change in the condition for moving the lever assembly about the two pair of crossed reeds and flexible sealing means for actuating the control means.

14. In a control device, a body having a passag therein, an opening through said body communicating with said passage, pivot means, movable means pivotally mounted on said body in proximity to said opening, lever means extending through said opening and engaging said movable means, and bellows means arranged about said lever means and attached to said body and said lever in a manner to seal said opening against passage of fluid therethrough, said'pivot means comprising crossed reeds arranged on diametrically opposite sides of said bellows in such a manner that the apparent axis of said crossed reeds extends through said bellows.

15. In a device of the class described, comprising in combination, a device to be actuated, a first chamber, a second chamber, the first chamber having outlet means communicating with the second chamber, bellows means sealing the outlet means communicating the two chambers, the device to be actuated arranged in the second chamber, pivot means comprising crossed reeds arranged on diametrically opposite sides of the bellows in such a manner that the apparent axis of said crossed reeds extend through said bellows means, condition responsive means arranged in the first chamber, and means connecting the condition responsive means with the bellows means, the condition responsive means responsive to a change in the condition for rocking the bellows about the pivot means for actuating the device.

16. In a device of the class described, comprising in combination, a control device. a first chamber, a second chamber, the first chamber having outlet means communicating with the second chamber, bellows means arranged in the second chamber and sealing the outlet means communieating the two chambers, pressure responsive means arranged in said first chamber, lever means connecting the pressure responsive means with the sealing bellows, and pivot means comprising crossed reeds arranged on diametrically opposite sides of the bellows in such a manner that'the apparent axis of said crossed reeds extends through said bellows, the pivot means connected to said lever means, the first chamber providing means so that differential pressures may be employed in the operation of the control device, the pressure means responsive to changes in pressure for rocking the lever means about the pivot and sealing bellows for, controlling the operation of the control device.

17. In a device of the class described, comprising in combination, means enclosing a space, said enclosing means having an opening, means extending through said opening, means operated by said extending means, means actuating said extending means, means sealing said opening about said extending means, and pivot means for said extending means, said pivot means comprising oppositely arranged crossed reeds, the axis of said pivotal means passing through said sealing means. a

18. In a device-of the class described, comprising in combination, means enclosing a space, said enclosing means having an opening, means extending through said opening, means operated by said extending means, means actuating said extending means, bellows means sealing said opening about said extending means, and pivot means for said extending means, said pivot means comprising oppositely arranged crossed reeds, the axis of said pivot means passing through said bellows sealing means.

19. In a device of the class described, comprising in combination, means enclosing a space, said enclosing means having an opening, means extending through said opening, means operated by said extending means, means actuating said extending means, bellows means sealing said opening about said extending means, and pivot means for said extending means, said pivot means comprising crossed reeds arranged in diametrically opposed relation on the outside of the bellows means, the axis of said pivot means passing through said bellows sealing means.

20. In a switch of the class described, comprising in combination, switching means, fuel pressure responsive means controlling the operation of the switching means, a housing comprising a chamber for sealing the fuel pressure responsive means from the switching means, the housing having outlet means, a flexible bellows sealing the outlet means from the housing, fuel pressure responsive means being a first seal means for the fuel pressure, the sealed chamber adapted to act as a second seal means for the fuel pressure, actuating means associated with the fuel pressure responsive means, the flexible sealing bellows means and the switching means, flexible pivot means comprising two pair of spaced .apart crossed reeds positioned adjacent the bellows means and connected with the actuator means, the fuel pressure responsive means responsive to changes in the fuel pressure for rocking the actuator assembly about an axis determined by the intersection of the two pair of crossed reeds for actuating the switching means.

21. In a switch of the class described, comprising in combination, switching means, fue1 pressure responsive means controlling the operation of the switching means, a housing comprising a chamber for sealing the fuel pressure responsive means from the switching means, the housing having outlet means, a flexible bellows sealing the outlet means from the housing, the fuel pressure responsive means being a first seal means for the fuel pressure, the sealed chamber adapted to act as a second seal means for the fuel pressure, and rocking means comprising the flexible bellows and a plurality of spaced apart crossed reeds positioned adjacent the bellows means, the fue1 pressure responsive means responsive to changes in the fuel pressure for moving the rocking means about an axis determined by the intersecting of 1 1 r s the plurality of spaced apart crossed reeds for actuating the switching means.

22. In a. device of the class described, a device to be actuated, force producing condition resp0nsive means for controlling the operation of said device, a lever, and a pair oi crossed reeds connected to said lever, the condition responsive means upon a change in the condition causin rotation of said lever substantially about an axis determined by the intersection of said crossed reeds for actuating said device, the force produced by said condition responsive means placing said reeds in tension.

23. in a device of the class described, a device to be actuated, force producing condition responsive means for controlling the operation of said device, resilient means opposing said condition responsive means, a lever, and a pair of crossed reeds connected to said lever, the condition i3esponsive means upon a change in the condition causing rotation of said lever substantially about an axis determined by the intersection of said crossed reeds for actuating said device, the force produced by said condition responsive means and said resilient means placing said reeds in tension.

2 in a device of the class described, a device to be actuated, force producing condition responsive means for controlling the operation of said device, resilient means opposing said condition responsive means, a lever, and a pair of crossed reeds connected to said lever intermediate said condition responsive means and said resilient means, the condition responsive means upon a change in the condition causing rotation of said lever substantially about an axis determined by the intersection of said crossed reeds for actuatme said device, the force produced by said condition responsive means and said resilient means nlacing said reeds in tension.

WILKES: H. GILKE.

REFERENEES The ioliowing references ace of record in the file of this patent:

UNITED STi JEES PATENTS