US2372464A

US2372464A - Thermostat

Info

Publication number: US2372464A
Application number: US439149A
Authority: US
Inventors: Weber Victor
Original assignee: Robertshaw Thermostat Co
Current assignee: Robertshaw Thermostat Co
Priority date: 1942-04-15
Filing date: 1942-04-15
Publication date: 1945-03-27
Anticipated expiration: 1962-03-27

Description

March 27, 1945. WEBER 2,372,464

- THERMOSTAT Filed April 15, 1942 INVENTOR. VicToR WEBER.

Patented Mar. 27, 1945 UNITE.

THERMOSTAT Victor Weber,

Greensburz,

ia assignor to Robertshaw Thermostat Company, Young wood, Pa., a corporation of Pennsylvania Application April 15, 1942, SerialNo. 439,149

' 2 Claims. (01.236-48) This invention relates to thermostat mechanisms and, more particularly, to those of the multi-lever snap-acting type.

An object of the invention is to permit manufacture and testing of the snap-acting mechanisms as complete units apart from the thermojustment before assembly.

Another object of the invention is to reduce the space required for the assembly by permit ting offset arrangement of the parts while retaining positive action thereof.

Another object of the invention is torender the device simple and compact and adapted for rapid assembly and relatively inexpensive to manufacture.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawing,

'of Fig. II;

Fig. V is a. section taken on the line V-Jil of Fig.

Figs. VI to IX are perspective views of parts of the lever mechanism.

Referring more particularly to the drawing, the control body is generally rectangular in stat proper to assure uniform and accurate adform, having substantially the same width and thickness but of greater length, and is provided with an auxiliary portion l2 .on one side thereof of less length than the main control body ill. The main body I9 is open on theside opposite the auxiliary portion l2 and is provided with a closure plate It secured thereto by means of the screws I6. The open side of the body lb does not extend for the full length of the body but terminates shcrtof one end thereof leaving a flange I8. An outlet is provided in the end of the body I0 adjacent the flange i8 and may be threaded or otherwise adapted for connectionv with a pipe leadingito the burner of the appliance with which the control isto be used.

. The auxiliary portion I2 is separated in part from the interior of the main body II) by a partition 22 whichextends lengthwise of the body l0 and is provided with a recess 24 having a bottom wall 25 and a side wall 28. The side wall 28 has an opening 30 therethrough providing access between the recess 2t and a valve chamber 32 formed by the space between the partition side wall 28 and the outer wall of the auxiliary portion i2 v The valve chamber 32 contains a. valve member 36 adapted to seat against the side wall 28 and control passage of fluid through the opening 3d. The valve member 341 is yielda'bly retained on its seat by means of a coil spring 36 extending between the valve member t t and a cap 38 threadedly engaging with an opening in the outer wall of the auxiliary portion i2 and providing access to the valve member when the cap 38 is removed. A stem w projects from the valve member into a stem guide 42 projecting from the cap 38 and the valve member may further be proyided with a projection 44 extending opposite the valve stem through the opening 39 and into the recess 26. 4

That portion of the auxiliary body l2 separated from the main body it by the bottom Wall 26 of the partition forms an inlet chamber 66 with which a pair of angularly disposed inlet penings t8 communicate. The inlet openings 48 may be threaded or otherwise adapted for connection with pipes leading from a source of fuel supp y. It will be apparent that only one such inlet as could be provided and only one is required to be -chosen for connection purposes but greater flexibility in installation is provided by the arrangement described. Due to the provision of the partition 22 which, as stated, extends throughout the length of the body III, the only Path of communication between the inlet 48 and outlet 20 is from the chamber d6 through the opening 30, controlled by the valve member 34, and into the recess 24 to the interior of the main body I0, with which the outlet 28 communicates.

The burner of the appliance which receives fuel from the outlet 20 operates in response to a thermostat carried by a boss 50 projecting from the main body ID on the side opposite the cap 38. The thermostat shown is of the rod-and-tube type, such as may be inserted in the storage tank of a water heating system with which the burner is associated.v The tube 52 of the thermostat of this embodiment has a high coeiiicient of expansion and is mo tea at its inner end in a threaded opening 54 of the boss 50. The rod 53 of the thermostat, which maybe oi invar or other materialhaving a low coe flicient of expansion, extends within the tube 52 and abuts a plug 58 threaded or otherwise secured in the end of the tube 52. The opposite end of the rod 56 abuts one end of a pin 60 which is slidable in the wall of the main body I and projects into the interior thereof. The rod 56 is supported in the tube 52 by spaced projections 6| extending-into slidable engagement with the interior surface of the tube.

The thermostat is adapted to operate, upon' cooling of the water irr'the storage tank of the water heater, by movement of the rod 56 to the right from the position shown in Fig. III, due to I2 carried by the frame 62. This lever I6 is channel-shaped and has part of its base removed, leaving an opening at the central portion there? of with spaced bar portions 83 and SI respective- 5 ly at each end connected by arms 93 at the sides.

with-the thermostat is provided by a stem 90,

contraction of the tube 52, which opens the valve 34-through the interposition of suitable multilever snap acting mechanism. Conversely, when the temperature in the storage tank increases,

the tube 52 expands, permitting the rod 56 to move toward the left to the position shown in Fig. III, causing movement of the valve member 34 to closed position through the same snap-acting means.

The bar portion 89 has its outer edge seated in the fulcrum seat 14 of the frame 62 as previously mentioned, a knife-edge bearing being provided on this edge. Operative engagement of the lever having a rounded end seated in a depression 92 formed inthe central portion of bar 89 of lever 16 and having its opposite end abutting the pin 60. The pin 90 is slidably mounted in a'bearing 15 portion 94 carried by the depending arm 96 of an angular stop plate 98 which is secured by means of the screws I00 to the flange I2 of the frame.

The width between the arms 93 of the thermostat lever I6 is sumclently less than that'between the arms 64 of the frame 62 to provide a space The multi-lever snap-acting. mechanism of this invention is entirely self-contained and. may be assembled and tested apart from the control body I0. The mechanism comprises aframe 62, upon which all of the levers are'mounted, and which has opposite arms 64 connected at one end of the frame by a tubular element 66. The element 66 is adapted for engagement at its opposite ends with a pair of pivots 68 carried by the flange I8 I and the opposite side wall of the body I0, respectively. The arms 64 are also connected by a back portion I0 which may be integral with the arms 64 and extends from the end opposite the tubular element 66 and terminates short'of this element. The portion I0 is provided with a flange I2 extending between the arms 64 at the end 0D- for the accommodation of the arms I02 of a valve operating lever I04. These arms I02 are connected at their upper portion by a. bar I06 extending between the thermostat lever I6 and arm 96 of the stop plate. The bar I06 has a recessed erally from the bar portion I06 across one arm portion I08 centrally disposed on its underside and a depressed bearing portion I I0 on the opposite side, the purpose of which will appear here- .inafter. A valve operating-arm II2 projects lat- 64 of the frame 62. Theoperating arm H2 is of sufficient length to project into the recess 24 of the auxiliary body portion. I2'when the-parts are assembled in the control body and carries a tip II4 which engages with the projection 44 of posite-the tubular element 66 andbeing provided with a notched portion "forming a fulcrum seat for a thermostat lever 16. The flange 12 is retained against displacement from its position between the arms 64 by short projections I8 formed on the arms 64 and overlying part of the flange I2 for this purpose.

I The pivots 68 which engage with the tubular element 66 015 the frame are preferably in the form of screws having threaded engagement with the control body I0 and being adjustable from. the exterior thereof. In thi manner, the pivots the valve member 84.

The bar portion 9| constituting the free end of the thermostat lever 16 is provided with a depressed bearing portion I I6 similar to the bearing portion H0 and adapted to accommodate one hook end II8 of a coil spring I20, the other hook end I22 of which engages with the bearing portion IIO of the lever I04. The spaced ends of the arms I02 of .the valve operating lever l04 are provided with"suitable knife-edge bearing per- 68 may readily be removed from engagement with the tubular element 66 and upon removal of the closure plate I4, the frame 62 and associated parts may be removed as a unit from the control body. Furthermore, such arrangement permits adjustment of the-frame 62 and the levers associated therewith on the pivots 68 from exterior of the control body I0. For this purpose, the side of the control body I0 opposite the boss is p otions I24 which are received within fulcrum seats I26 formed on the. arms I28 ofa channel-shaped support I30. The support I30 is pivotally mounten'on the arms 64 of the frame 62 by the provision of notched bearings I32 formed on the arms 64 adjacent the tubular element 66 and providing support for the opposite ends of a pin I34 extending between the arms I28 of the support I30. Inorde'r to prevent the thermostat lever I6 from displacement, a limit stop pin I36 may provided with an additional boss 18 which may be hollow and have projecting therethrough a threaded adjusting pin 80 which can be moved into and out of engagement with the frame portion 10 by an adjusting handle or dial 82.

The dial 82 may be fastened to the pin 80 by means of a headed screw 84 having its threaded end inserted in an axial hole in the pin 80, there being a coil spring 86 extending between the-underside of the dial 82 and the bottom of the hollow boss I8. The dial preferably carries a pointer ject from the channel-shaped support I30 into the path of movement of the lever I 6.

A tail-piece I38 may extend from the base of the channel-shaped support I30 and project at an angle thereto in the opposite direction to the 88 which cooperates with suitable indicia marked on the surface of the control body I0 to indicate the temperature setting of the device.

The snap-acting leverage carried by the frame 64 comprises three principal parts. The thermostatlever 16, as previously mentioned, has a ful-' crum seat in the notched portion 14 of the flange ature arms I28. The tail-piece I38 carries a screw I40 which can be adjusted to bear against the tubular element 66 and, by changing the position of fulcrum seat I26 relative to that of fulcrum seat I4, serve to-change the tension of the spring I20 within limits as desired. Movement of the valve I operating lever I04 may be limited by the proasvascs that for which the dial 82 has been set. When the tube 52 of the thermostat becomes cold due to cooling of the water in the storage tank, the rod 56 moves to the right, exerting pressure upon the lever 16 to move it in a counter-clockwise direction about its fulcrum seat 14. Suflicient movement of the lever 18 in this direction will carry the end 8 of the spring I20 far enough tothe right of the fulcrum seat I26 to enable the spring to exert sufficient force upon the valve operating lever I04, to move it to the right with a snap action to open the valve 32. After the tube 52 has again become sufliciently heated, the pressure of the rod 06 on the thermostat lever 18 is relieved sufflciently to permit movement of this lever in a clockwise direction, returning the end II8 of the spring I22 to its original position and permitting the spring I20 to move the valve operating lever I04 to the left with a snap action 'and permitting the valve 84 to close.

By adjusting the dial 82 to move the end of the pin 80 toward or away from the frame 62 the position of the frame 62 and therefore the position of the thermostat lever I8 may be varied with respect to the rod 58 of the thermostat to set the temperature at which the mechanism will operate. The adjusting dial 82 engages the frame 62 intermediate the pivots 08 and the stem 90 ofthe thermostat. Thus, any looseness which develops in the pivotal mounting will not afiect the accuracy of the adjustment as might be the case if the mounting were otherwise arranged with respect to the dial and thermostat.

The device lends itself readily to assembly of the snap-acting mechanism in considerable quantities and testing thereof in a single test body. When the snap-acting mechanism has been thus by said frame and comprising a thermostat lever having one end fulcrumed on the end of said frame opposite the pivotal mounting, a support fulcrumed on said frame at the and opposite said thermostat lever, an operating lever fulcrumed at one end on said support-and extending toward the fulcrumed end of saidthermostat lever, a

tension spring connecting said levers, an operating'arm projecting laterally from said operating lever for operative engagement with said valve member, means adapted for axial movement relative to said actuating means and being engageable with said thermostat lever adjacent the fulcrumed end thereof, said axially movable means being responsive to thermostatic operation for causing movement of said valve member by snap-action of said actuating means, limit stop means extending into the path of said levers for retaining said actuating means in said frame, and adjusting means carried by said main body and engageable with a portion of said frame intermediate the pivotal mounting and the. plane of said axially movable means for varying the position of said actuating means relative to said axially movable means.

2. Snap-acting thermostat mechanism comprising a main body having a fluid passage, an auxiliary body disposed at one side of said main body and having a fluid passage, a valve member tested and its operation checked in the test body,

it can be assembled in final position in any stand ard control body with the assurance that further testing will be unnecessary. Considerable space is conserved by the provision of the offset arrangement of the valve with respect to the thermostat while retaining the positive snap-acting operation of the valve. It will be understood that various changes may be made in the construction and arrangement of the parts as described and shown herein without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. Snap-actin thermostat mechanism comprising a main body having a fluid passage, an auxiliary body disposed at one side of said main body and having a fluid passage, a valve member reciprocable in said auxiliary body and controlling communication between said passages, a frame pivotally mounted at one end thereof in said main body. valve actuating means "carried reciprocable in said auxiliary body and controlling communication between said passages, 81 frame pivotally mounted at one end thereof in said main body, valve actuating means carried by said frame and comprising a thermostat lever having one end fulcrumed on the end of said frame opposite the pivotal mounting, a support fulcrumed on said frame at'the end opposite said thermostat lever, an operating lever fulcrumed at one end on said support and extending toward the fulcrumed end of said thermostat lever, a tension spring connecting said levers, an operating arm projecting laterally from said operating lever for operative engagement with said valve member, pin means engageable with said thermostat lever adjacent the fulcrumed end thereof and being responsive to thermostatic operation for causing movement of said valve member by snap-action of said actuating means, a limit stop carried by said frame and extending into the path of said operating lever, said limit stop having an aperture through which a portion of said pin means slidably extends, a second limit stop carried by said support and projecting into the path of said thermostat lever, said limit stops cooperating to retain said actuating means in said frame, and adjusting means carried by said main body and engageable with said frame for varying the position of said actuating means relative to said pin means.

VICTOR