US2817973A - Safety device - Google Patents

Description

Dec. 31, 1957 R. B. GLICKMAN 2,817,973

SAFETY DEVICE FiledDec. 22, 1954 INVENTOR. RICHARD B; GLICKMAN BY 34 34C 281) ATTORNEY fiiice SAFETY DEVICE Richard lit. Glickman, Los Angeles, Calif., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minm, a corporation of Delaware Application December 22, 1954, Serial No. 477,100

3 Claims. (Cl. 74-2) This invention relates to limit controls and, more specifically, to limit controls which have to be manually reset after the control has moved to its off position in response to a predetermined condition arising.

One of the objects of this invention is to provide a simple, compact, inexpensive, and thoroughly reliable limit control which can be set or reset into and be retained in its on position only if a predetermined condition does not exist.

Another object of the invention is to produce a limitcontrol power unit which is sufiiciently small as to be able to replace a thermocouple power unit in conventional safety pilots.

Still other objects of the invention will become apparent upon reading the following detailed description of the invention in conjunction with the accompanying drawings wherein:

Figure l is a vertical sectional view of the invention;

Figure 2 is a cross sectional view of the invention taken along line 22 of Figure l, and

Figure 3 is a plan view of the motor portion of the condition responsive unit.

While it is to be understood that the invention could embody a switch as well as a valve or any other control means, it is illustrated in the form of a valve which is substantially identical to that disclosed in a copending application of James M. Cunnien and Melvin G. Sogge filed May 20, 1953, Serial No. 356,202.

The valve consists of a lower casting 11 having an inlet 12 and an outlet 13 with a dividing wall 14 therebetween. The lower casting 11 is open at its top and has a peripheral edge 15 that lies in a flat plane inclined at an angle to the longitudinal axis of the inlet and outlet of the valve body. The partition wall 14 has an opening 16 therein which is substantially coaxial with the inlet and outlet and has a valve seat 17 machined in the inlet side of the partition around the opening 16.

The valve body also includes an upper casting 18 that is open at its lower edge and has an aperture 19 in one side wall thereof for mounting a power unit therein, to be presently described. The lower peripheral edge of the upper casting lies in a fiat plane that is inclined to the axis of the inlet 12 and outlet 13 at the same angle as the upper edge of the casting 11. The upper casting 18 is secured to the lower casting 11 with a sealing gasket 20 therebetween by means of bolts (not shown) extending freely through bores (not shown) in the upper casting and threaded into aligned bores (not shown) in the lower casting. The two castings, when so bolted together, form a generally rectangular shaped hollow housing or valve body that encloses the operating mechanism for the valve head now to be described.

The valve head 21, having a soft facing 22 made of rubber or other suitable material, is supported at the lower end of a bell crank lever 23 in a conventional manner, withan annular rib on the soft facing 22 adapted to engage with the valve seat 17 when the valve is in its ofi position. The upper portion of the lever 23 is of channel shape, which has a wide aperture 23a therein.

The aperture 23a joins with a centrally disposed aperture 23b at the lower end of the aperture 23a, with the width of the aperture 23b being less than half the width of the channel portion. The upper end of the aperture 23a is spaced a short distance from the upper end of the channel portion and forms a cross bar arm 230 as the other arm of the bell crank lever 23. The lever is pivoted on a pivot 24 supported in grooves 25 (not shown) in the upper casting 18, with the pivot being held in said grooves by means of projections (not shown) on the lower casting 11.

Another bell crank lever 25 has an intermediate channel shaped portion 25a and is pivoted at its upper end .to the casting 18 on the same pivot 24 as is the lever 23.

One arm of the bell crank lever 25 extends downwardly and transversely from the channel shaped portion 25a, through the aperture 23b in lever 23, to a point spaced from but substantially in axial alignment with the center of the valve 21. A coil tension spring 26 has one end thereof hooked through an aperture 25b in the lower end of the lever 25 and the other end thereof hooked through an opening 23d in a transversely bent portion of the lower end of the lever 23. This spring normally holds the lower end of the slot 23b in the lever 23 against the lever '25 but will stretch to permit separation of the lever 25 from the lever 23 for a purpose to be hereinafter described. The other end or arm of the bell crank lever 25 extends laterally from the pivot 24, on the opposite side of the pivot 24 from the arm 23c on lever 23, and has an offset portion 250 which is, normally, substantially in alignment with the arm 23c and the pivot 24.

A condition responsive unit 27, consists of a bracket member 28 of channel shape, a bellows unit 29, a temperature responsive bulb 30 and a capillary tube 31 extending between the bulb and the bellows.

A bracket 28 has an aperture 28a therein, for mounting purposes, outwardly struck ribs 28b in the sidewalls thereof, for strengthening purposes, and inwardly struck arms 30 with notches 30a therein to support a leaf spring 31 in engagement with the free end of the bellows 29.

The condition responsive unit 27 is held in its assembled relationship in the valve body by means of a v threaded shank 29a on the bellows 29 extending through sealing washers 32, the opening 28a in the bracket and the opening 19 in the valve body 18, and tightly clamped 7 to the wall of the valve body by means of a nut 33 threaded on the threaded stem 29a externally of the valve body. The capillary tube between the bulb and bellows is filled with a suitable expansible fluid, such as xylene, so that upon a predetermined temperature occurring at the bulb 30, the bellows 29 will be expanded sufy A wider projection 34c merely rests in a wider notch 28d in the bracket. Slidable in the sleeve 34, is a plunger 35 having a reduced diameter portion 35a at one end thereof and an annular groove 35b at the other end thereof,

Patented Dec. 31, 1957 The reduced diameter portion extends through the opening 23a in lever 23 and the opening 25d in the lever 25. A spring thrust collar 36 is secured on the portion 35a against the main portion of the stem 35 by means of a split ring 37 engaged in anannular groove in the portion 35a. An abutment collar 38 is slidably supported ontheportion 35a and is retained thereon by means of asplit: ring 39 engaging in an annular groovein the portion 35a. and is resiliently urged. against the. lever 25 by means of a coil compression spring. 40extending between the collar 38 and another abutment collar 41, which, in turn, is retained on the extreme outer end of the stem portion 35a by means of another split ring 42 engaging in an annular groove in the portion 35a. The spring 40 is sutiiciently strong as to hold the lever 25. against the spring cup 36 at alltimes.

Extending through two diametrically opposed slots 42 in the sleeve 34, is a coil spring 43, generally known as a garter spring, which has its ends anchored to two spaced lugs 34d formed on the flange 34a. This spring is of sufficient strength as to hold the, plunger 35 in engagement therewith against the bias of spring 44 extending between the flange 34a and. the spring retainer cup 36 for; normally biasing valve 21 to its closed position. However, the, spring 43 is not sutficiently strong as to hold the plunger 35 against the combined forces of the spring and the force exerted by the bellows 29 against the plunger 35. For calibrating purposes, a nut 45, having a projection 46 thereonrfor engagement with the bottom of a bore 350 in the plunger 35, is screw threaded on a threadedboss29b formed on the/free end of the bellows 29. The nut 45 is locked in its adjusted or calibrated position by meansof a jam nut 47;

The manual means for actuating the valve to its open position, with the plunger 35 in latching relationship with respect to, thewspring 43, isthesametas that in the above mentioned Cunnien et, al. patent application. It consists of a plunger-48textending through a bore 18a and carryingat its inner end afloating lever 49 arranged to engage-at one endwith. the arrn23c'and its other end with the arm 25c. The lever 49.-is retained on the plunger 48 by means of two split-rings50 engaging in annular grooves in thestem48. on' opposite sidesiof the.lever 49. Mounted on the outer. end of the.stem 48;is. a pushbutton 51 slidable in a bore 52.formed in1a.boss.53.extending upwardly from the top of the, valve. body:casting 18. A coil spring 54 extends between. the pushbutton.5'1: and a spring retainer, cup 5,5 and agassealing Q-ring.:,56-.located between the, springretainercup 55' and? the outer surface of the wall 18. A sealing washer 57; is;also positioned between the upper; swirling-1503 and inner'surface of the valve body 18. The spring 54 will normallyzholdzthepushbutton in its arisedaor. outermostposition but isyieldable to permit manualmovement of the=plunger 48.and the lever 49*into engagementwithzthelevers 23 and 25. Downwardly'proiecting arms 49a,on, the lever 49 extend along the side of the pivot 24 tol prevent rotation of therlever 49 out of. alignment with theyportions 23c:and.25c.

Operation The device is,illustrated in its; on position. Thatis, the bulb 30 is below thetemperatureat which; the bellows 29 will, expandsufficiently to engage-theplunger- 35land force it out of-engagement. with, spring; 43. Should. the temperature of the bulb. increase to a, predetermined amount, as for example 200. degrees, the. temperature at which, itwould be dangerous to further heat a hotwater tank, the bulb 30, which is inpositioned to sense thetemperature of the water in the, tank, will expand the fluid in,t hebulb andjconsequently expand the bellows 29 sutliciently to force the plunger out of engagement. with the spring-4'3; As soon as .the.plung er is free of the spring 43, ,the spring 44will causethe, lever 25'to move counterclockwise about the pivot 24 and force the lever 23 and 4- the valve carried thereby into their off positions with the valve 21 seated against the valve seat 17. This will shut off the fiow of gas through the valve to the burner for heating the water in the tank.

To reset the valve after the water in the tank has cooled below the control point, it is necessary to manually move the plunger 51 inwardly. The inward movement of the plunger will cause the floating lever 49 to bear against the lever 23 and the lever 25 and, as the lever 23 cannot move counterclockwise due to the fact that the valve is resting against the valve seat, only the lever, 25, will be pivoted about the pivot 24. This will cause stretching of the spring 26 and movement of the piston 35 by the lever 25 to its latched open position with the spring 43 in engagement with the angular groove 35!). As long as the plunger 51 is held inwardly, no gas will How to the burner. Only upon release of the button 51 will the spring 26 be able to pull the lever 23 and the valve carried thereby in a clockwise direction around the pivot 24 to their open positions. It is thus seen that it is impossible to move the valve to its open position unless the bulb 30'has cooled down sufficiently to permit the fluid in the bulb and bellows to contract and free the plunger 35 for movement to its latched open psoition.

While I have described the preferred embodiment of the invention, it is deemed to be apparent that various modifications may be made in the preferred embodiment of the invention without parting from the spirit thereof. Therefore, the scope of the claims should be determined solely-from the; appended claims.

I claim:

1; A control device comprising a generally U-shapcd bracket having an opening in the base thereof, a bellows positioned within said bracket and having a shank portion thereof extending through, said, opening for securing said bracket to the control device, said bellows being connected to a condition sensing bulb, a flanged sleeve secured to the ends of the bracket with its axis coaxial with said bellows, said sleeve having parallel and diametrically opposed slots therein, control means having a stem slidable in said sleeve and having an annular groove therein, a garter spring extending substantially around said sleeve and lying in said slots for engagement in said annular groove to hold said member in its on position, and manually operable-means for actuating said control to its on position.

2. A safety device comprising a bracket, condition responsive means positioned Within said bracket and having a shank portion thereof extending through an opening in said bracket for securing said bracket to the safety device, a flanged sleeve secured to the ends of the bracket, said sleeve having substantially parallel and diametrically opposed slots therein, a garter spring extending substantially around said sleeve and lying in said slots, a control member, actuating means for said member including a stem having a groove therein, said spring being registerable with said groove to hold said member in its on position, and manually operable means operably connected to said actuating means and movable in one direction to move said stem into registration with said groove while holding said control member in its off position and movable in the opposite direction to permit said control to be moved to its on position by said manually operated means.

3. A control device comprising a control member having a groove therein, condition responsive actuating means for operating said control member, a bracket having an opening in the base thereof, a bellows in said actuating means positioned within said bracket and having a shank portion thereof extending through said opening for securing said bracket to the control device, said bellows be ing connected to a condition responsive bulb of said actuating means, spring means on said bracket engaging a free end'of said bellows and tending to compress said bellows,

a flanged sleeve secured to the ends of the bracket and having its axis substantially coaxial with said bellows, said sleeve having substantially parallel and diametrically opposed slots therein, resilient means extending substantially around said sleeve and in said slots for engagement in said groove in said control member to hold said member in its on position, and manually operable means for moving said control member to its on position.

References Cited in the file of this patent UNITED STATES PATENTS Kellogg Nov. 7, 1933 Craver July 6, 1937 Mantz Aug. 21, 1945 Weber Dec. 7, 1948

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