US2303994A - Thermostatic snap action valve mechanism - Google Patents

Description

Dec. 1, I942. N. B. GREEN 2,303,994

THERMOSTATIC SNAP ACTION VALVE MECHANISM Filed April 26, 1941 25 3| 9 l0 33 20 22 w w L 25 32 3o "*1 J FlG.-4 24 I7 I 27 2A 29" l2 4 7 FIG "5 24 28- 4 I jr/ INVENTOR 4E a/ NOEL B. GREEN /E: BY 2'6 29 l3 l5 F|G 3 v ATTORNEYS Patented Dec. 1, 1942 2,393,994 THERMOSTATIGS/NAP ACTION VALVE MECHANISM Noel B. Green, 016781311115'01110; author to' The Titan Valve and Manufacturing Company,

Cleveland, Ohio, a corporation ofOhio Application April 26, 1941, Serial No. 390,529

2 Claims. (01. 236-40 This invention relates to improvements in thermostatically operated snap acting mechanism.

An object of the present invention is to provide mechanism of the class described adapted to be concealed within the exterior shell of a hot water tank or other like equipment within which is a medium, the temperature of which is to be controlled.

Another object of the invention isto provide snap acting mechanism housed in an enlongated narrow shank which may be substantially embodied in a tank by threading the shank into an opening in the casing so as to provide a close coupled thermostatic mechanism lying close to the wall of the tank and withvery little thereof protruding beyond the protecting sheila Other objects and advantages of the mecha nism include the arrangement of the parts for cheap production and easy assembly, for easy and simple adjustment of the mean thermostatically controlled temperature and other advantages which will be apparent from the accompanying drawing and specification, and the essential features of which will be set forth in the claims.

In the drawin Fig. 1 is a central longitudinal section through my improved mechanism showing a thermostatically operated valve in open position; Fig. 2 is a similar sectional view showing the valve in closed position; Fig. 3 is a transverse sectional view taken along the line 3-4 of Fig. 1; Fig. 4 is a top plan view of the removable snap acting lever mechanism of Figs. 1 to 3; while Fig. 5 is a fragmental sectional view showing a modification.

In the embodiment of the invention here disclosed, a housing 5 having an elongated generally cylindrical shank 8 may be inserted in the wall 1 of a water heater tank or the like by means of the threaded connections at 6a. Axially alined with-the shank 8 is a thermostatic rod 8 of relatively nonexpansible material housed in a tube 9 of relatively expansible material. These two form a thermostat of the ordinary type operatively connected together at the inner end of the thermostat iii. The housing is enlarged at II to provide a gas inlet chamber i2 to which an inlet pipe may be connected at It and to provide a gas outlet chamber it to which an outlet pipe may be connected at it. The sole communication between chambers l2 and I4 is provided at the valve seat It which is closed by a valve ll urged by spring I! which rests against closing cap it. The entire portion ll of the wall 20 i'orming'the outer shell of the tank cover.

the only portion of the device extending outside of the shell 20 is a small boss II which carries the temperature adjusting screw 22 with n indicator dial 23.

nap acting lever mechanism is provided for transmitting the movement of the thermostatically controlled rod 8 to the valve II. This snap lever mechanism is so designed and arranged that it will fit within the long narrow confines of the shank 6.

To this end the main lever 24 and the snap acting lever 25 are arranged in a generally end to end relationship rather than in the customary side by side relationship.

As here shown the snap acting mechanism is carried by a sheet metal frame 26 generally of channel shape opening upwardly as viewed in Figs. 1 to 3. The bottom wall of the frame as indicated at 26a, Fig. 3, may lie on an arc of lesser radius than the bore' 8b of the shank 6. The shank 'is broached at the points 21 to receive the upper square comers of the channel frame so that the frame is held against turning in the shank but is adapted to be moved longitudinally thereof. v

The main lever 24 has its longerleg lying within and extending longitudinally of the frame 26. The shorter leg 24a of this lever has a fulcrum on the inner end edges of the frame 28 as best seen in Figs. 1 and 2. As there shown the fulcrum 28 is at'the free end of the shorter legto' one side of which at 29 is a countersunk recess for receiving the end of the rod 8. This provides a lever of the third order although it will be readily understood by those skilled in this art that much the same result may be obtained by reversing the position of the points 28 and 29, thus giving a lever of the first order.

The snap lever 25 is also of general L-shape having its longer leg lying withm the channel frame and extending toward and generally in alinement with the longer leg of lever 24. The end of lever 25 toward the right in Figs. 1, 2 and I 4 is fulcrumed at the points 30 on the side walls of the channel frame. The shorter leg of lever 25 extends laterally outside of the frame 28 at the point 25a to engage the nose of valve ii. A portion of the end wall of frame 26 may be bent inwardly as indicated at 3| to lie in a slot of lever 25, thus limiting its motion. In the form here shown the frame 28 has had the side walls of the channel cut awayas at 2th to receive the 2 asoaoea snap lever 28 and to provide the fulcrum points. 24. I A tension spring 22 connects snap lever 2| with the free end of the longer leg of lever 24 in a manner to urge both of these levers toward their fulcrums. The lever 2l has its center cut away at lib to receive the spring 22. It will be noted in comparing Figs. 1 and 2 that the point 22 where spring 22 is connected to lever 24 is carried by oscillation of lever 24 from a position above fulcrum II in Fig. 1 to a position below fulcrum 24 in Fig. 2. In other words when the parts are in the position of Fig. 1, lever 25 snaps clockwise under the influence of spring 32 to cause valve II to open, whereas when the parts have moved to the position of Fig.2, valve i1 is closed by the action of its spring II.

It will be noted in Figs. l-and 2 that the central axis of the helical spring 32 is substantially alined with the fulcrums II and 22 and it results from this construction that very slight movement of lever 24 is necessary to cause the effec- 1 and 2 when the tube! rigidly connected the casing I moved toward the right as the were heated causing the rod to move tothe rllht also with the resultant counterclockwise movement of lever 24. Obviously the reversemovementofthepartsofFIgStakes place upon the cooling of the casing. 8. In this modification therefore I have done away with tive force of spring 32 to be exerted on one side 'or the other of fulcrum 30 to cause opening or closing of valve i1.

It will be noted that turning of theadlusting screw 22 will adjust the position of frame 26 longitudinally of shank 8 sons to cause the fulcrum 28 of lever 24 to be moved nearer or farther from the end of rod]. This adJustment therefore affects the mean temperature controlled by the thermostat.

In Fig. 5 I have shown a modification of the right-hand end of Figs. 1 or 2, it being understood that the apparatus is otherwise similar to that already described. In this form'instead of relying for the thermostatic action. upon the conventional thermostat such as shown at 8, 9, it of the first form described, I have relied upon the fact that the casing 8 made of brass or similar material having a high coefilcient of expansion will expand at a difl'erent rate .from the frame 2| which is made of steel or other material having a relatively low coefllcient of expansion. It will be noted that the frame 28 is held 'flrmly at the left end of easing 8 by its abutment against the adjusting screw 22. Therefore when the casing 6 is heated as by immersion in hot water, it

will expand toward the right more rapidly than the frame 28. The point 84 on the casing 6 engages the point 29 on the lever 24 so as to control the position of this lever about its fulcrum 28. Therefore the point 34 will move toward the right as viewed in Fig. 5 relative to the fulcrum 28 (when the casing B is heated) thus causing lever 24 to oscillate in a counterclockwise direction about its fulcrum. This is the same movement as described previously in connection with the conventional thermostatic element 8, s shown inl 'igs. 1 and 2 and am relying upon the casing O and the frame 24 to produce the thermostatic action. If necessary or desirable the parts 6 and 24 might be made longer than shown in Figs. 1 and 2 if necessary to produce the proper thermostatic action.

What I claim is:

l. Snap actuating mechanism of the character described, comprising a channel shaped frame, L shaped main and snap levers housed within said frame, said levers being provided with long arms lying in end to end alined relation and with laterally extending short arms at their remote ends, the short arm .of the main lever and the long arm of the snap lever being fulcrumed in the frame, a snap tension spring connecting points on the two levers remote from their fulcrums and holding both levers to fulcrum seats in the frame, the short arm of the main lever being exposed at one end of the frame for operation by a thermostatic device which moves generally along a line extending lengthwise of the alined lever arms, and the end of the short arm of the snap lever being adapted to operate a device by movement at right angles to such line.

2. Thermostatic snap actuating mechanism of the character described, comprising a chambered casing having a hollow body portion and a tubular extension, a frame mounted for endwise movement in said tubular extension, two L-shaped levers pivotally carried in said frame and movable therewith, a spring connecting said levers, said levers having their free arms extending in the same direction'and lying generally in end to end alined relation with a transverse arm of one lever exposed at one end of the frame and a

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