US2633517A - Thermal control device - Google Patents

Description

March 31, 1953 R, w, GUSTAFSON 2,633,517

THERMA CONTROL DEVICE Filed May 28, 1952 Ralph WGusJafson, bz' Www His At'boP-neg.

Patented Mar. 31, 1953 UNITED STATES v`PATENT OFFICE THERMAL 'CONTROL DEVICE Ralph'W. Gustafson, Fulton,-fll., assignor toGen- .cral Electric Company, a eorporation of New York Application May 28, 1952, Serial No. 290,471

10 oiaims. 1

This Zinvention 'relates to control devices, and --morejparticu1ar1y vto devices'for Operating 'electricswitches responsively vto temperature changes in' a 'selected location.

'Theprincipal object of the invention is to provide a simple, reliable, and easily constructed `in the vpreceding paragraph which, 'after it has -operated to discontinue voperation of the furnace, automatically restores itself 'to 'its initial condi- -tion 'so -that'it is ready again to operate normal- -ly'as a 'controllerfor the Warm-air fan when the operation of the furnace is resumed.

Other-Objects, advantages and features of my -invention will be apparent from the subsequent description of a preferred embodiment thereof, while Sthe-scope of1t'he invention is set forth in :the appended claims.

In 'carr-ying out my invention in one form, =I provide a control'device having a'sha'ft connect- 'ed to a helicalbimetal'member-and arranged for .rotationalinovement'in either direction responsively to vchanges in the temperature of `the bimetal. A pair of Operating members are a'djusta'oly mounted on the shaft, and each oper- -ating vmember has `an Operating arm iforming a portion thereof these arms extend-adjacent each other in a direction substantially parallel to the 'shaft `An electric switch having two positions :and snap-action meansfor maintaining the switch `norn'ialiy in one of these positions is supported ina suitable manner adjacent the two Operating arms. A cantilever spring actuating member is provided for 'the switch, this actuating member being arranged to oppose the Said maintaining means 'With a force such 'that the switch remains ineither of its two positions to which it is moved by movement of the actuating member. .A portion of the aotuating member extends bem tween the two said Operating arms whereby the rotation of the shaft in one direction engages oneo'f the arms with the actuating member and moves the switch to a first of its two positions, 5

' been 'second of its two positions.

(Cl. .ZM- 138) and. a movement of' the shaft in the other direotion engages the ,other of the Operating arms with the actuating-member and operates'the switch to the A third Operating member with an Operating arm thereon may be provided'on'the shaft for Operating a second electric switch.

For a clear and more complete understanding of my invention, reference should be 'had to the aocompanying drawing in which Fig. 1 showsa front -elevationxview of a combination warm air vfan and ;limit device embodying this invention, with the cover 'removed and 'a portion of the device .cut away;

Fig. 2 isa sectional 'View valong the linek-2 of Fig. 1;

Fig. l3 is a sectionalview along the line 3-3 of Fig. 2;

Fig. 41is .an exploded view of apQrtiQn of the combined Warm air fan and limit device of the preceding figures;

Agenerally by the numeral l O in Figs. 1 and 2. p'IYhis controldevice in its lessential elements comprises a metal tubular-portion 1| 'housing a Vhelical'bimetal member i, and a rectangular housing portion i which contains a switching mechanism v designated generally 'by the numeral 14.

The tubular portion -l-| vof vthe device should be suitable 'for installation in the -warm air bonvnet offla furnace or other location, to the temperature of which it isA desiredthat the device respond.

rdinarily, atleastrall'of the portion of member l surrounding bimetal l2 is positioned within the heated space, while a portion of the right hand end of tube H and the housing |3 project beyond the wall of the heated space. Mounting means (not shown) are ordinarily provided on 'member i i to secure the device to such a wall. A n of the right hand portion of tube il has omitted from Figs. 2 and 3 of the drawing, but it should be understood that this portion lof tube i is made of lsuilicient length to provide adeouate insulation between the portion of tube il is within the Warm air chamber and the exte val housing it containing the swtching Also, it will be readily understood by 'those familiar with controldevices of this nature aceasm that other insulating means, such as an insulating shield (not shown) around tube il, for example, may be utilized between housing E3 and the furnace, if necessary, to prevent the switching mechanism within the housing from becoming overheated.

As shown in the drawing, the helical bimetal |2' is mounted upon and supported by a projection IB of a rotatably adjustable disk IE which fits Within vand substantially closes tube li. Bimetal I 2 is secured firmly to projection it in a suitable manner such as by spot welding. Disk I5 is connected by a longitudinally disposed member il to a second disk 88 which also fits closely within tube H in order to close the tube but is rotatable for adjustment purposes. The bimetal [2 and the associated rotatably movable structure 55, l, ll, E8 are maintained within the tube li by an angular portion E9 projecting from disk U8. secured to the rear wall 58 of housing IB by a screw 2! which passes through a slot in projection E9 and engages the threads in a suitable threaded opening in the rear wall 55. The slot 20 in the projection 553 provides for a small rotational adjustment of the bimetal to provide the initial calibration of the control device.

The other or left hand end of the bimetal as seen in Fig. 2 is secured to a shaft 22 in a suitable manner such as 'by spot welding. The shaft 22 extends longitudinally through helical bimetal I2 and through the suitable openings in disks |5 and E8 into the housing l. As the temperature of bimetal i2 changes the shaft 22 is caused to rotate in one direction or the other depend- :f

ing upon the direction of temperature change, the disks E5 and i providing bearing surfaces for the rotation of shaft 22.

A scale member 23 is rigidly secured to the opposite end of shaft 22 for rotation therewith. As shown, this scale member comprises an assembly of two laminations for case of manufacture. The inner lamination is of steel and is welded to the shaft 22, while the Outer lamination containing suitable indicia is secured to the inner lamination tO form a unitary scale member.

As illustrated, the control device includes three Operating members 24, and 22 mounted on shaft 22 for rotation with the shaft and scale member 23. These Operating members are best seen in Fig. 4 of the drawing, which also shows other elements providing frictional means for holding these Operating members for rotation with shaft 22 and scale member 23 and at the same time providing for the adiustment of the Operating members with respect to each other and the scale member 23. As shown, these frietion means comprise a friction member 27 positioned between Operating members 24 and 25, a friction member 28 positioned between operating members 25 and and a spring member 29 which holds Operating members 2d, 25 and 25 and friction members 27 and 28 'adjustably in position against scale member 23. Spring member 29 is curved and has a depressed portion 29a in the center, as seen in Fig. 3, to press against the other members, and may be secured tO scale member 23 by a pair of rivets 311 and 3|. Friction disk 277 has an arm 32 having an indentation 33 in the end thereof, which indentation embraces rivet 3% and holds frietion member 21 fixed with respect to the scale member 23. Friction member 25 has a similar arm 34 with an indentation 25 in the end thereof The projection ie is adjustably which embraces the other rivet 30 to prevent friction disk 22 from moving.

With this arrangement, if the pressure exerted by spring 29 is properly chosen, the Operating members 2d, 25 and 2G rotate with scale member 23 during operation of the control device, but thesev Operating members may be adjusted with respect to the scale member 23 by restraining the latter member and moving the Operating member which it is desired to adjust. T'O facilitate the adjustment of the Operating members, each is pr-ovided with a projection which extends through a suitable opening in the scale member 22. These projections are desgnated respectively 32, 31 and 38 for Operating members 24, 25 and 26. Projections 25 and 21 extend through an opening 39 in scale member 23, while projection 38 extends through an Opening 463. A projection Lil, which is shown as an extension of rivet 35B, may be provided on the outer surface of scale member 23 to facilitate holding scale member 23 while one of the Operating members is adjusted by moving the outwardly extending portion of one of projections 35, 3'! Or 38. Fig. 1 shows how indicia may be provided on the Outer surface Of scale assembly 23 to indicate the settings of the three Operating members.

Each of the Operating members 24, 25 and 26 operates an electric switch under selected conditions, and for this purpose each of these Operating members is provided with an Operating arm. These are designated 42, 43 and M respectively for Operating members 24, 25 and 26. As shown, Operating arms 132 and 43 are arranged to operate an enclosed switch 45 while the third Operating arm is arranged to operate a second enclosed switch 46. These switches may be secured to the rear wall 53 of housing G3 by means of brackets 41 and 48 respectively. As shown, the brackets M and 48 are secured to the rear wall by means' of rivets 49 while the switches, in turn, are secured to the brackets by screws 5B.

The switches 45 and 46 are of the snap-acting type, each employing an over center or other suitable mechanism to provide| snap action, and each having a return spring or other means for causing the respective switch to remain normally in One of two Operating positions. One suitable switch mechanism which may be used in these switches is shown in U. S. PatentA 2,429,8l8, granted to George M. Hausler on October 28, 1947, however, many Other similar switches providing snap action between two positions and employing a return spring or other restoring means are known and may be used in this control device if desired.

A cantilever spring actuating member 5! made of a suitable resilient material is provided for switch :35, and as shown in the drawing, particularly in 2, 5-7, this actuating member is mounted upon an upward extension 52 of switch mounting brac-kot '27. Actuating member 5i is secured to extension 52 in any suitable manner, such as by spot welding, and arranged to engage an Operating button 55 of switch 25. Actuating member 5! is. positioned on bracket l' so that it exerts an Operating force on the operating button 55 of switch 45 in a direction Opposite to that exerted by the restoring mechanism in the switch. Actuating member 5! should be so ohosen and arranged that it exerts a sufficient force On switch 45 that this switch will remain in either of its Operating positions. That actuating member 5l is so ohosen that the force which it exerts is not suicient. completely has operated; thus, when the device is used as a combined warm air fan and limit controller, the device cannot be set to operate the limit switch 46 before switch 45 has turned on the fan. This is accomplished by providing at the proper location on Operating member 25 an ear portion 25a which engages arm 44 on member 255 in case it should be attempted to adjust members 25 -and ft in a manner which Would provide. other than a proper sequenee of operation for the two switches.

The housing l3 as shown in the drawing includes a rear wall 58, a top wall 59, a bottom wall 60, and two partial side walls ti. The housing is closed by a cover member 62 which is substantially U-shaped, having an elongated front portion 63 and a pair of elongated side portions 64. The cover may be secured to the remainder of the housing by a pair of screws 65, only one of which is shown, which engae'e suitable threaded apertures 55 in projections 61 extending inwardly from the top and bottom walls 59 and 68. Within the housing there may be provided a flat member 63 of insulating material which is secured to inwardly turned projections 89 on the partial side walls 6! of the housing by means 'of screws 'HI which engage suitable threaded apertures 1| in projections 69. As shown, insulating member 68 has an opening vin which scale member 23 is located, with the outer surface of the scale member approximately flush with the outer surface of insulating member 68. If desired, terminals 12 may be provided at the bottom of insulating member 68. As will be readily understood, these terminale ordinarily are connected to the switches'll and 46, although the conductors for this purpose have been omitted from the accompanying drawing in order to simplify it. The control device li! is connected to the apparatus which it is to control by external conductors brought into the enclosure |3 and connected to terminale 12.

It will be apparent from the foregoing that my invention provides a simple and easily constru'cted control device which may be used, for example, as a warm air fan and limit device for a furnace. Moreover, the device automatically restores itself to its initial normal Operating condition after an excessive temperature so that it is ready again for normal operation as soon as the cause of the excessive temperature has been removed.

While I have illustrated my control device as embodying a bimetal el-ement making it responsive to temperature changes, it will be readily understood that 'other physical condition responsive devices may be substituted, if desired. Furthermcre, this invention is not limited to use with a rotating shaft but is adaptable, also, for use with Operating members having rectilinear or other motions.

Other modifications likewise will occur to those skilled in the art and, therefore, it should be understood that I intend to cover by the appended claims all such modifications which fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A control device comprising, a shaft member arranged for rotational movement in either direetion, a pair of Operating members adjustably mounted on said shaft, each Operating member havingr an Operating arm and the two Vsaid arms extending adjacent each other, a switch having two positions and snap action means maintaining said switch normally in one of said positions, and a cantilever spring actuating member for said switch arranged to oppose the said maintaining means with a force such that said switch remains in either of the said two positions to which it is moved by movement of the said actuating member, a portion of the said actuating member being located between the said two arms whereby the rotation of the said shaft in one direction engages one of said arms withl the said actuating member and operates the said switch to a first of the said two positions. and the rotation of the shaft in the other direction engages the other arm with the actuating member and operates the switch to the second of the two positions.

2. A control device comprising, a first member arranged for movement in either of two opposite directions, a pair of Operating members adjustably mounted on said first member, each Operating member having an Operating arm and the two said arms extending adjacent each other, a switch having two positions and means maintaining saidswitch normally in one of said positions, and a spring actuating member for said switch arranged to oppose the said maintaining means with a force such that said switch reniains in either of the said two positions to which it is moved by movement of the said actuating member, a portion of the said actuating member being located between the said two arms whereby the movement of the said first member in one direction engages one of the said arms with the actuating member and operates the said switch to a first of said two positions and the movement of the first member in the opposite direction engages the other arm with the actuating `member and operates the switch to the second of the two positions.

3. A control device comprising, physical condition responsive means, a first member connected to said condition responsive means and arranged for movement in either of two opposite directions responsive to changes in the physical condition, a pair of Operating members adjustably mounted on said first member, each Operating member having an Operating arm and the two said arms extending adj acent each other, a switch having two positions and restoring means normally maintaining said switch in one of the said positions, an actuating member for said switch for moving it to either' of the said two positions, said actuating member being arranged to oppose the said restoring means with a force such that said switch remains in either of the two positions to which it is moved, a portion of said actuating member being located between the said two arms whereby the movement of the said first member in one direction engages one of the said arms with the actuating member and operates the said switch to a first of the said two positions and the movement of the first member in the opposite direction engages the other arm with the actuating member and operates the switch to the second of the two positions.

fi. A control device comprising, physical condition responsive means, a shaft member arranged for rotational movement in either direction responsiveiy to changes in said condition responsive means, a pair of Operating members adjustably meunted on said shaft, each operating member having an Operating arm and the two said arms extending adjacent each other and substantially parallel to said shaft, a switch aaaur having two positions and' means for maintaining said switch normally inone of said positions, a cantilever spring actuating member for said switch for moving it to either of the said twopositions, said actnating member being arranged to oppose the said inaintaining means with a force such that said switch remains in either of the said two positions to which it is moved, a resilient extension portion on said actuating member extending transversely of the said shaft and between the said first and second arms, and: a shoulder portion of said resilient extension portion` for engaging one of said arms, whereby'when said shaft rotates in one direction responsively to a change in said physical conditzon in av certaindirection said one arm engages said shoul-V.

der portion and actuates said switch to a first of'its two positions, and when said shaft rotates in the opposite direction responsively to a change in the` physicai condition in the other direction said second arm engages said actuatimT member andfmoves said switch to the second of its two positions.

5. A thermal control device comprising, a helical bimetal member, a shaft connected to saidv mcvement in bimetai member for rotational either direction responsively to changes in the temperature of the said biore-tal, a pairV of operating members adjustably mounted on said shaft each provided with an operating arm, the two said Operating arms extending adjacent each other and substantially parallel with said shaft with one arm the other, a switch having two positions and snap action means maintaining said switch normally in one of said positions, a cantilever spring ac-v bimetal rotates said shaft in one direction responsiveiy to a change in the temperature of the bimetal in a certain direction whereby sa1d switch is actuated to the first of its two positions, the` other arm engaging said actuating member upon rotaticn of said shaft in the opposite direotion esponsively to a change in the temperature. of the bimetal in the opposite direction and moving said switch to the second of its two positions.

6. A thermal control device comprising, ahelical bimetal member, a shaft connected to said bimetal member for rotational movement in either direction responsively to changes in the temperature of the said bimetal, an indicating scale member secured to one end of said shaft and arranged for rotaticn therewith, a pair of operating members arranged on said shaft adjacent the said Scale member, means secured to said scale member for yieldingly urging said operating member toward the scale member so as to be rotatable therewith, friction means in contact with the said Operating members providing for the rotational adjustment of the Operating members with respect to each other and the scale member, a pair of Operating arms forming portions respectively of the said Operating members and extending away from said scale member in substantially parallel relation with the said shaft, a rst one of said Operating arms being adjacent to the second more remote from the shaft thanV arm butHat-a greater distance from the saidV shaft than the said second arm, an electric switch having two positions and snap action means for maintaining said switch norma-1137 in one of the said two positons, a cantilever spring actuating member forsaid switch arranged to onpose the said maintaining means for the-said sv-zitch with a force such that said switch remains in either of the said two positione to which it is moved by the. movementofthe said actuating member, a resilient; substantially right-angleextension portion on actuating member extending trans-. versely of the said sha'ft and between the saidr rst'and second arris, and an offset portion onsaid resilient extension portion forming a shoulder which engages said second arm when said bimeta-l rotates saidshaft in one direction re-- sponsiveiy to a change in the temperatureiofthe. bime in-a predetermined direction whereby saidv switch isactuated to the rst ofits two positions, said firstarm engaging said actuating member upon rotation of said shaft in the opposite direction responsiveiy to a. change in the temperature of the bimetai in the opposite direction and moving sadswitch to the second of its two positions,

'1. A control device comprising, a first member arranged for moi/ement in either of two opposite; directions', a pairof Operating members adjustably mounted on said first member, each Operating said arms cxtending adjacent each other, a switch having two positions and means maintaining said` switchnormally in one of said positions, a spring actaating member for said switch arra-nged' to, oppose the said maintaining means with a,v force such that said switchl remains in either of the said two positions to which it is moved by move,-l ment of the said actuating member, a portion of j the said actuating member being located between the said two arms whereby the movement of the said first member in one direction engagesV one, of the saidv arms with the actuating'member and, operates the said switch to a first of said twow positions and the movement of the first member in the opposite direotion engages the other arm with the actuating member and operates the, switch to the second of the two positions, a third; Operating member provided with an Operating; armgand adjustably mounted onsaidfirst member, and a second electric switchgarranged to be operated by the armof said third Operating member upon movement of said first member in said one; direction a predetermined amount beyond;` the amountnecessary to operate said first switch to; its said irstV position.

8.l control device comprising, a shaft memberl -arrangedV for rotational movement in either direction, a pair of Operating members adjustably mounted on said shaft, each Operating member having an Operating arm and the two said arms extending adjacent each other, a switch having two positions and snap action means maintaining said switch normally in one of said positions, a cantilever spring actuating member for said switch arranged to oppose the said maintaining means with a force such that said switch remains in either of the said two positions to which it is moved by movement of the said actuating member, a portion of the said actuating member being located between the said two arms whereby the rotation of the said shaft in one direction engages one of said arms with the said actuating member and operates the said switch to a first of the said two positions and the rotation of the shaft in the other direction engages the other arm with the actuating member and operates the switch to the second of the two positions, a third Operating member having an Operating arm and mounted adjustabiy on said shaft, and a second electric switch arranged to be operated by the arm of said third Operating member upon movement of said shaft in said one direction beyond the point at which said first switch is operated to its said first position.

9. A thermal control device comprising, a helical bimetal member, a shaft member arranged for rotational movement in either direction responsively to changes in the temperature of said bimetal, a pair of Operating members adjustably mounted on said shaft and each provided with an Operating arm, the two said Operating arms extending adjacent each other and substantially parallel with said shaft with one arm more remote from the shaft than the other, a switch having two positions and a restoring means normally maintaining said switch in One of said positions, a cantilever spring actuating member foi` said switch arranged to oppose the said restoring means with a force such that said switch remains in either of the said two positions to which it is moved by movement of the said actuating member, a resilient extension portion on said actuating member extending transversely of the said shaft and between the said two Operating arms, a shoulder portion on said resilient extenu sion portion for engaging the less remote of said arms 'when said shaft is rotated in one direction thereby to actuate said switch to its restored position, the second arm engaging said actuating member upon rotation of said shaft in the oppofl site direction and moving said switch to its nonrestored position, a third Operating member having a third Operating' arm and adjustably mounted on said shaft, and a second electric switch arranged to be operated by the said third arm upon rotation of said shaft in said one direction a predetermined amount beyond the amount necessary to operate the said first switch to its restored position.

10. A combination Warm air fan and limit device comprising, a helical bimetal member, a shaft connected to said bimetal member for rotational movement in either direction responsively to changes in the temperature of the said bimetal, an indicating scale member secured to one end of said shaft and arranged for rotation therewith, three Operating members arranged on said shaft adjacent the said Scale member, means secured to the said scale member for yieldingly urging all of the said Operating members toward the scale member so as to be rotatable therewith. friction means in contact with the said Operating 12 members providing for the rotational adjustment of the Operating members with respect to each other and the scale member, three Operating arms forming portions respectively of the said three Operating members and extending away from said scale member in substantially parallel relation with the said shaft, a first one of said Operating arms being adjacent to a second one of the said arms but at a greater distance from said shaft than the said second arm, a first electric switch having two positions and snap action means maintaining said switch normally in one of said two positions, a cantilever spring actuating member for said first switch arranged to oppose the said maintaining means for said first switch with a force such that said first switch remains in either of the said two positions to which it is moved by the movement of the said actuating member, a resilient substantially right angle extension portion on said actuating member extending transversely of the said shaft and between the said first and second arms, an offset portion on said resilient extension portion forming a shoulder which engages said second arm When said bimetal rotates said shaft in one direction responsively to a change in temperature of the bimetal in a certain direction and thereby actuates said first switch to a first of its two positions, said first arm engaging said actuating member upon rotation of said shaft in the Opposite direction responsively to a change in the temperature of the bimetal in the opposite direction and moving said switch to the second of its two positions, said resilient extension portion being arranged so that said second arm is released by the shoulder thereon if the said bimetal rotates said shaft more than a selected amount in said one direction, and a second electric switch arranged to be operated by said third arm upon the rotation of said shaft in said one direction a predetermined amount after the release of said second arm by said shoulder.

RALPH W. GUSTAFSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 22,131 Lindemann July '7, 1942 2,158A3'7 Shaw May 16, 1939 2204231 Rudolph June 11, 1940 2,490,073 Malone Dec. 6, 1949 2,511,271 Kaminky et al. June 13, 1950 2,532,383 White Dec. 5, 1950

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