US2280651A - Thermostat - Google Patents

Description

April 21, 1942.

l c. G. KRONMILLER THERMOSTAT Filed Apri1p19, 1957 Inventor Carl G. Kfom/zz'ZZef Patented Apr. 2l, 1942 UNITED- s'rATEs PATENT oFFlcE THERMOSTAT Carl G. Kronmiller, Minneapolis, Minn., assigner to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application April 19, 19347, Serial No. 137,725

' 24 claims. (ci. zoo-139) Thisinvention relates to thermostats and more particularly to a thermostatic structure embodying a timed operating mechanism and provided with means to shift the control of the instrument from a predetermined day temperature to a predetermined night temperature.

A primary object of this invention is the provision of an improved thermostatic switching mechanism provided with a day-night shift embodying improved means for providing a change from day to night temperatures and vice versa atpredetermined times.

An additional object is'the provision of means in such a mechanism whereby the day temperature controls the mechanism actuated by the instrumentunless the timed mechanism in association with the device is in operative position.

A further object is they provision of such a mechanism whereby unless the setting of the night temperature indicator is below that of the day temperature indicator the day temperature will control in such manner that the night setting may never be higher than the day setting.

An additional object is the provision in a structure to be hereinafter described of means whereby the day and night temperatures may be predetermined independently of each other and the instrument readily adjusted to operate the controlled mechanism at such temperatures.

As conducive to a clearer understanding of this invention, it may here be pointed out that in numerous temperature or other condition controlling installations it is desirable that thermostaticmeans be provided to control a source of heat, such as a burner or furnace, in such manner that during the night, or during such period of time as the occupants are out of the dwelling or otherbuilding, it is desirable that the temperature be reduced to a lower level than during the day or during such periods of time as the given period within the scope of the operating range 4of the instrument and thereafter auto- 'matically returned to a higher temperature- In such instruments it is desirable that both the lower and higher temperatures may be readily varied but it is undesirable that the normal lower temperature should ever be in excess of the normal higher temperature, whereby upon the operation of the instrument in such a manner that the lower temperature should take control actually a higher temperature will prevail.

It is a further object of this invention to preclude such a contingency.

A still further object is the provision of such a. mechanism which will be simple oi construction, readily operable by unskilled persons and sturdy and durable in construction.

Other objects will in part be obvious and in part pointed out hereinafter.

The invention, accordingly, consists in the combinations of elements, arrangements of parts and structure is occupied. For various reasons, such asy economy, it is sometimes undesirable that a continuously operating clock thermostat be provided. In such cases it is advantageous to have a thermostat of relatively simple and inexpensive construction having timed means associated therewith whereby the temperature may be reduced from a given setting to a relatively lower settingffor a desired period, at the termination of which 4period the setting will return to the previously mentioned higher temperature.

One object of this invention is the provision ot an improved thermostat of the above mentioned character provided with timed mechanism whereby the temperature may be reduced for any features of construction all as will be more fully pointed out hereinafter and disclosed in the accompanying drawing.

Referring now to the accompanying drawing wherein an illustrative embodiment of the inventive concept is disclosed:

Figure l is a front elevational view of a structure embodying the instant invention showing the cover in position and various external operating mechanism;

Figure 2 is an enlarged front elevational view of the device with the cover and certain other parts removed for the sake of clarity;

Figure 3 is an enlarged side sectional elevational view taken along the line 3--3 of Figure 1 as viewed from the left: f

Figure 4 is a sectional view taken along the line 4-4 of Figure 2 as viewed from the bottom;

Figure 5 isa sectional view taken along the line 5-5 of Figure 2 as viewed from Ithe t0n;

Figure 6 is a sectional view taken along the line 6--5 of Figure 2 as viewed from theleft;

and

Figure '7 is a. bottom elevational view of portions of the structure shown in Figure 2.

Similar reference characters denote similar parts throughout the several views of the drawing.

Referring now to the drawing in detail and more particularly to Figure 3, a mounting plate generally indicated at l0 is secured to a wall or other suitable surface (not shown) as by screws or in any other desired manner. A base plate All which, in turn, carries the operating distortion of base plate I! by excessive tightening of the fastening means.

Base plate li has mounted thereon a casing i 4 as by screws i5, which casing contains a clock mechanism (not shown) which may be of any suitable type but preferably contains those embodhnents disclosed in the (zo-pending applicaftion of Andrew G. McNicoll Serial No. 98,288, now PatentNo, 2,108,776, filed August 28, 1935,

entitled Starting mechanism? and assigned to the same assignee. The clock mechanism is pro vided with a winding stem i8 adapted to be ro tated in a manner to be described hereinafter to a tension the mechanism to rotate for a predetermined time period, which in the illustrative embodiment herein shown will be in the neighborhood of 11 or 12 hours, and includes a slip friction mechanism as disclosed in the above mentioned McNicoll application for a purpose to be later pointed out.

turn, is electrically associated with a third terminal carried by mounting plate ||I. Suitable screws 55 secure member 5| in insulated relationship with base plate I I as shown in Figure 5, and corresponding screws 56 secure member 54 in a similar manner.

A U-shaped insulating bracket 60 is secured as by a rivet 8| to member 53 and positioned, as better shown in Figure 5, so that the extending portions of the U are located on opposite sides of member 46 to prevent displacement of member 46 and consequently contact 41 from its normal alignment with contacts 49 and 52. Means are also provided whereby the position of contact button 52 may be varied to change the operating dierential of the instrument in a known manner. Such means comprise an internally and exteriorly threaded member 62 engaging a threaded aperature in member 53 and having a screw 82a threaded therein, screw 82a carrying contact button 52. Threaded member 52 is provided with a dial 83 carrying suitable indicia thereon. A pointer 54 comprises an integral portion of member 53 and the adjustment of dial S3 with respect to pointer 84 indicates the relative position of contact 52 and hence the operating differential of the instrument. Screw 62a may be independ- Resiliently mounted on winding stem I6 in a manner to be described hereinafter is a lever I1, the distal end'of which is positioned for abutment a with an end I8 of a lever I8 mounted on a pivot 20. Lever I9 isyconnected as by a link 25 and a pin 28 to an inwardly turned portion 21 of a U- shaped bimetallic element 28 through a rivet 28.

Bimetallic element 28 is provided with an extending bracket 30, as better shown in Figure 4,

y having inwardly turned apertured portions'p0si tioned adjacent a second bracket 3| also provided with registering apertured portions similar to bracket 30. A pivot pin 32 passed through the registering apertures thus permits pivotal movement of bimetallic element 28. A spring 33 one end oi.' which engages a suitable aperture 34 in bracket 3| and a second aperture 35 in bimetallic element 28 normallyA biases bimetallic element 28 ure 2 about pivot 32.

Mounted and secured as by rivets 48 on either side of base plate is a pair of insulating panels 4| and 42. Bracket 3| is secured to insulating vpanel 4I `in such'a ,manner that it is electrically insulated from base plate for a purpose to be hereinafter set forth. Bracket 3| has an extending portion which is in electrical association with screw'l2a which, in turn, extends to a suitable terminal (not shown) in mounting plate- The opposite end of bimetallic element 28 carries a member. which is, in turn, provided with` a contact button 41'. l Contact button 41 is adapted when in one position to engage a contact 49 carried by an arm 50 in electrical association, through an extending portion 5| with screw I2b, which, in turn, is electrically asso-f' ciated with a second terminal carried by mount- 'ing plate III. When in its other position contact button 41 is adapted to lengage a contact 52 carried by an arm 53 in electrical association, through a member 5 4 with screw |2c, which, in

in a, counter-clockwise direction as viewed yin Flgently rotated and sealed during manufacture to provide factory calibration.

It may here be pointed out that `a wire 10 leads from a terminal 1| on member 54 to a resistance element 'l2 carried by a receptacle 13 in electrical association with bracket 3| and hence screw I 2a and its associated terminal, the purpose of which resistance element is primarily to impart an artificial increase in temperature to the space adjacent bimetallic element 28 inl a known manner and for a. known purpose in order that the mcve ment thereof may be accelerated under certain conditions.

Lever I8 at an end 15 opposite end I8 carries an extending portion 18 provided with a. threaded aperture in which is positioned a screw 11 4adapted to abut, under certain circumstances to be hereinafter described, a cam 18 secured for rotation as by a nut 18 upon a shaft 80 mounted within a sleeve 8| (see Figure 6). The oppositeend of shaft 88 is rigidly secured as by a rivet 88a to a dial 82 carrying indicia on the face thereof and having an arcuate slot 83 extending about a circumferential portion thereof. A member 84 secured in any suitable manner to insulating plate 42 has an inwardly turned portion 85 extending into slot 83 and serves as a stop to limit rotation of dial 82- and hence cam 13. An extending portion 88 of base plate |I is curved inwardlyl to provide a pointer adjacent the indicia carried by dial 82.

It should here be pointed out that sleeve 8| is rigidly and non-rotatably secured to base plate II. A second sleeve 88 surrounds sleeve 8| and is provided with a cam 8| which may be integral therewith. Rigidly secured to sleeve is a second dial 82 also bearing indicia thereon but of smaller circumference than dial 82. Dial 82 is also provided with an arcuate slot 88 into which projects an end 84 of a member 85 suitably secured to insulating plate 4|, the abutment of member 84 with the ends oi' slot 83 serving as a stop to limit the rotationoi' dil 82. A second lever 88 is carried by pivot 20 but is curved outwardly adjacent an end 81 in such a mannerthat the combined ends 15 of lever I8 i and 91 of lever 88 comprise a Y. The end 81 is provided with an 11p-turned portion 88 having a threaded aperture therein through which projectsascrew99similartoscrew11butpositioned for abutment with cam 9|. A spring |88 `extends between portions 98 of lever 8l and 18 of lever |9 for a--purpose to be described adapted to abut dial 82 and by the pressure exerted thereagainst hold the same from rotation. l

Referring again to lever I1, it will be seen .that the same is provided with a U-shaped portion generally indicated at |02 (see `Figure 1) and comprising a pair of substantially parallel apertured portions |03 and |04 which encircle winding stem I6 of clockworks I4 and are freely rotatable thereabout. The'center |80 of the U-shaped member |02 is providedwith a slotted aperture through which is passed ay screw |01 engaging winding stem I6. 'A coil Aspring member |08 has one end secured aboutscrew |01 and the other end engaging in a suitablev aperture |09 in lever I1, spring |08 being 'so arranged as to bias lever I1 in a direction towards end I0 of lever I9. Thus it'will be seen' that the spring |08 in combination 'with slot |80 and screw |01 serves as a strain release permitting a relatively slight rotation of winding stem I8- with respect thereto and similarly a relatively slight rotative movement of lever I1 with respect to winding stem I8.

Now from the foregoing it should appear that when lever I1 is in the position as' shown in Figure 2 in abutting relation with end I8 of lever I9, end of lever I9 and, correspondingly, screw 11 will be biased into abutting relationship with cam 10 and that rotation of cam 18 will vary the position of lever I9 since the previously described strain release will permit such limited motion asmay be imparted thereto by adjustment of the cam. It will likewise be seen that such motion of lever I9 will be imparted through link 25 and pivots 20 and 28 to bimetallic element 28 and consequently to contact button 41 moving the same towards one or the other of contacts 52 or 49. It will" further be seen, however, that as the lever I1 is'moved away from the end I8' of 'lever I9 the lever will be free to move in response to 'pressure exerted thereon through bimetallic element 28, which pressure is imparted theretoby spring 33, in such a manner-that screw 11 may m'ove away from its associated cam 18 and screw 98' move towards its associated cam 9|, and that under such circumstances movement' imparted to dial 92 will be transmitted 'through leverl 91 to lever I9 and hence to bimetallic element 28. It should here be pointed out that spring |00 is of greater strength than spring 3l and that hence in the 4absence of pressure imparted by lever I1 to the end I8 of lever I9 movement imparted to screw 99 `by cam 9| is directly imparted to bimetallic element 28 since the levers 96 and I9 when in the relationship above mentioned provide substantially an integral unit. It will further be seen, however, that the cams I0 `and 9| are so positioned and arranged that when dial 82is l:lusted to a temperature of. illustratively, 60"'l ould cam 8| be adjusted by dial 92 to a temperature of, illustratively, 70 the radius of of cam 9| is into abutting thatecrew 11 will be brought 18 with respect to the radius noniip therewith and spring |00 will thereupon yield in such a manner that the temperature of the day setting, namely 60, will be the controlling temperature of the instrument.

Referring again to winding stem It, it will be seen, as best shown in Figure 3, that a sleeve ||0 is positioned thereabout and held in position thereon as by a set screw III. A resilient collar |I2 is positioned upon a shoulder of sleeve IIO, which sleeve frlctionally engages a dial III bearing indicia', thereon. This indicia is visible through'an aperture |I4 in a casing IIS which normally encloses the mechanism previously described. A portion of. aperture I|4 is formed into a pointer ||6. Secured to dial III as by pins |I9 extending intosuitable apertures therein is a sleeve I 20 provided with a knurled portion |2| which extends exteriorly of the casing.

An operating handle |22 is rigidly secured to winding stem I0 as by a screw |23. A friction disc |24 is positioned between the lower. surface of operating handle |22 and the upper surface of sleeve |20. Casing IIS is provided with suitable slots through which the upper peripheral portions of dials 82 and 92 as well as pointer 88 project. These slots in connection with a screw |25 engaging a suitable inwardly turned lug |21 of base plate II serve to hold the casing and its associated mechanism in related assembly. Casing II5 is also provided with graduations indicative of temperature degrees, and positioned' interiorly of the casing and adjacent a slot |28 is a thermometer |29 which may be held in place in any suitable .manner as by a vertically extending strip |30 .engaging an inwardlyY turned portion III adjacent the lower portion of the casing and secured to a correspondingly inturned portion |32 in the upper portion of the casing as by a screw |98.

Suitable 4lead wires (not shown) are adapted to be directly connected to the vterminals engaged by screws I2a, I2b, and I2c on base plate I0. These wires may lead to any suitable con- .trol apparatus such as an oil or' gas burner, a

stcker motor or a draft regulator or any other desired heating apparatus.

From the foregoing the operation of the device should now be apparent. Assuming that the device is set as shown in Figure 2 to operate at a day temperature oi 70 and a night temperature of which settings may be readily varied, as will be appreciated, by rotation of the dials 8T and 92, and the occupant upon retiring desires that the night temperature become eii'ective for a period of, illustratively. 8 hours until a time, say one hour before rising. The occupant therefor need only rotate dial II3 until the highest number on the scale, which in the illustrative embodiment shown is I2, is adjacent pointer IIS and then rotate operating handle |22 which will wind the clock mechanism and simultaneously through friction disc |24 move dial II3 until the figure 8 is adjacent pointer IIS. Such movement will pcsition lever I1 a substantial distance from end I8 of lever I9, the distance gradually decreasing'as the 8 hour period progresses and during the time that the lever I1 is out of screw 99 with respect to cam 9|. At the termina- 4 tion/ of such operating period, the abutment of lever I1 with-end I8 will cause a movement of lever I9 in a clockwise direction as viewed in Figure 2 until such time as the screw'l'l abuts its associated cam 18 whereupon the day temperature setting as determined by the position `of cam 18 will again-take effect. During either upon engagement withthe hot contact 52 a re-* verse operation will ensue. It should also be pointed out that if the occupant is leaving the house at, illustratively, three oclock and desires that the temperature be reduced until, say live `ocloclc, planning to return at six, he need only rotate dial H3 to such a position that a number indicative of the time of day, in this instance 3, is adjacent pointer IIB and then rotate operating handle |22 until the number 5 indicative of the time at which he wishes the high temperature to again become effective is adjacent pointer IIB and the device will .operate at night temperature until the hour designated by the last numeral ljuxtaposed to pointer III. It should also be noted that if-the operator imparts too much tension to the clock mechanism reverse rotation of handle |22 will relieve such tension through the slip friction mechanism previously mentioned whereby an .accidental incorrect setting of'the device may be remedied.

Thus from'the foregoing, it will be seen that there is herein provided a device which accomplishes all of the objects set forth hereinbefore and others inA an improved manner including many advantages of great practical utility.

As many embodiments may be made of the hereinbefore described invention and as many modifications may be made )of the embodiment described, it is to be understood that all matter described or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a device of the -character described, in combination, a condition responsive element, condition control means operative by said element, first means for varying the position of said condition responsive element to vary the value of the condition to which said condition responsive element responds, second means for varying the position' of said condition responsive element to vary the value of the condition to which said condition responsive element responds, timed means to render one of said position varying means inoperative for a predetermined period, and means for varying the duration of said means to render one of said position varying means inoperative for a predetermined period, means'for varying the duration of said period,

pointer for indicating the duration of said period.

3. In a device of the'character described, in combination, a condition responsive element, condition control means operative by said element, means for adjusting said `condition responsive element to respond to a given value of'a condition, second means for. adjusting said condition responsive means to respond to a given value of a condition, means to render said rst mentioned adjusting means inoperative for a predetermined period, and means precluding the operation of said condition control means by said second mentioned adjusting means when the said second `means is set for a higher condition value than said first mentioned adjusting means.

4. In a device of the character described, in combination, a condition responsive element, condition control means operative by said element, a lever associated with said element, said lever comprising two members pivoted with respect to each other, resilient means normally biasing said members towards each other, a second resilient means biasing one of said members away from the other and stronger than said first mentioned resilient means, means for moving one of said members, and means for rendering said second resilient means ineffective for a predetermined period vwhereby said members may bemoved as a unit.

5. In a device of the character described, in combination, a condition responsive element, condition control means operative by said element, a lever associated with said element, said lever comprising two members pivoted with respect to each other, resilient means normally biasing said members towards each other, a second resilient means biasing one of said members away from the other and stronger than said first mentioned resilient means, means for moving one of said members, means for rendering said second resilient fr eans ineffective for a predetermined lperiod -whereby said members may be moved as a unit, and means for varying the duration of said predetermined period.

6. In a device of thecharacter described, in combination, a condition responsive element, condition control means operative by said element, a lever associated with said element, said lever comprising two members pivoted with respect to each other, resilient means normally biasing said members'towards each other, a'second resilient means biasing one of said members away from the other and stronger than said first mentioned resilient means, means for moving one of said members, means for rendering said second resilient means4 ineffective for a predetermined period whereby said members may be moved as a unit, means for varying the duration of said predetermined period. and means visually indicating the duration of said predetermined period. s

' '7. In a device of the character described, in combination, a condition responsive element, means operative by said condition responsive element to control the value of a condition, a

,timed mechanism, an abutment means associated with said timed mechanism for varying the position of said condition responsive element, said abutment means comprising a projection adapted when said timed mechanism is lnoperative vto hold said condition responsive element is one positlui and when said timed mechanism is operative to perm t said condition responsive meanstto e another, position.

and means including a numbered dial and a means to vary` the conditiofvaluc to which said condition responsive element responds when said timed mechanism is in operation, and secondA means'to vary the value to which said condition responsive means responds when said timed mechanism is operative.`

8. In a device of the character described, in

lcombination, a condition responsive element,

means operative by said condition responsive element to control the value of a condition, a timed mechanism, an abutment.means associated with said timed mechanism for varying the position of said condition responsive element, said abutment means comprising a projection adapted when said timed mechanism is inoperative to hold said condition responsive element in one position and when said timed mechanism isI operative to permit said condition responsive means to assume another position, means to vary the condition value to which said condition responsive element responds when said timed mechanism is inoperative, second means to vary the value to which said condition responsive means responds when said timed mechanism is operative, means for rendering said timed mechanism operative for a predetermined period and visual means for indicating the duration of said period 9. Ina device I the character described, in combination, a temperature responsive element, a timed mechanism, temperature control means operated by said element in response to variations in the value of a condition, means associated with said timed mechanism for changing the temperature value to which said element responds when said timing mechanism is operative, rst means for predetermining the temperature value to which said element responds when said timed mechanism is inoperative, second means for predetermining the temperature value to which said element responds when said timed mechanism is operative, means for predetermining the duration of the operating period of said timed mechanism, and means precluding the operation of said temperature control means at the temperature value to which said second temperature value predetermining means is set when said last mentioned value is in excess of the setting o said iirst temperature value predetermining means.

10. In a device of the character described, in combination, a temperature responsive element, a timed mechanism, temperature control means operated by said element in response to variations in the value of a condition, means associated with said timed mechanism for changing the temperature value to which said element responds when said timing mechanism is operative, iirst means including a cam and a cam follower associated with said temperature responsive element for predetermining the temperature to which said element responds when said timed mechanism is inoperative, second means including a cam and a cam follower associated with said temperature responsive element for predetermining the temperature value to which said element responds when said timed mechanism is operative, and resilient means associated with said temperature responsive element to hold said iirst mentioned cam follower in engagement with its associated cam when said timed mechanism is inoperative, and to move said second mentioned cam into engagement with its associated cam `follower when said timed means is rendered operative.

11. In a device of the character described, in

combination, a temperature responsive element, a timed mechanism, temperature control means operated by said element in response to variations in the value of a condition, means associated with said timed mechanism for changing the temperature value to which said element responds when said timing mechanism is operative, rst means including a cam and a cam follower associated with said temperature responsive element for predetermining the, temperature to which said element responds when said timed mechanism is inoperative, a second means including a cam and a cam follower associated with said temperature responsive element for predetermining the temperature value to which said element responds when said timed mechanism is operative, and resilient means associated with said temperature responsive element to hold said first mentioned cam follower in engagement with its associated cam when said timed mechanism is inoperative, and to move said second mentioned cam into engagement with its associated cam follower when said timed means is rendered operative, said cams being so arranged that if said second temperature value predetermining means is set at a higher value than the first temperature value predetermining means said temperature control means responds to the value at which said first temperature value means is set regardless of the operation of said timing means.

12. In a thermostatic switching mechanism, in combination, a bimetallic element, condition control mechanism operated by said element, a lever associated with said bimetallic element, said lever comprising two pivoted members, each provided with a cam follower, a pair of cams each adjacent one or" said cam followers, a pair of dials, each iixedly associated with one of said cams, a pointer, indicia on said dials indicative of temperature values, rotation oi said dials serving to vary the position of said cams in accordance with the temperature value adjacent said pointer, a timed mechanism, means associated with said timed mechanism to `iuxtapose one of said cam followers to its associated cam, whereby the position of said lever and hence said bimetallic element is determined by one of said cams when saidv timed mechanism is operative and the other of said cams when said timed mechanism is inoperative in such manner that said element responds to one temperature for the duration of the period of operation of said timed mechanism and another temperature value subsequentto the termination thereof.l

13. In a thermostatic switching mechanism, in combination, a bimetallic element, condition control mechanism perated by said element, a lever associated with said bimetallic element, said lever comprising two pivoted members, each provided with a cam follower, a pair of cams each adjacent one of said cam followers, a pair of dials, each fixedly associated with one of said cams, a pointer, indicia on said dials indicative of temperature values, rotation of said dials serving to vary the position of said cams in accordance with the ternperature value adjacent said pointer, a timed mechanism, means associated with said timed mechanism to juxtapose'one of said cam followers to its associated cam, whereby the position otsaid lever and hence said bimetallic element is determined by one of said cams when said timed mechanism is operative and the other of said cams when said timed mechanism is inoperative in such manner that said element responds to one temperature for the duration of the period of operationv of said timed mechanism and another temperature value subsequent to the termination thereof, and means for varying the duration of the operating period of said timed mechanism.

14. In a .thermostatic switching mechanism, in combination, a bimetallic element, condition control mechanism operated by said element. a lever associated with said bimetallic element, said lever comprising two pivoted members, each provided. with a cam follower, a pair of cams each adjacent one of said cam followers, a pair of dials, each flxedly associated with one of said cams, a pointer, indicia on said dials indicative of temperature values, rotation of said dials serving to vary the position of said cams in accordance with the temperature value adjacent said pointer, a timed mechanism, means associated with said timed mechanism to juxtapose one of said cam followers to its associated cam, whereby the position of said lever and hence said bimetallic element is determined by one of said cams when said timed mechanism is operative and the other of said cams when said timed mechanism is inoperative in such manner that said element responds to one temperature for the duration of the period of operation of said timed mechanism and another temperature value subsequent to the termination thereof, means'for varying the duration of the operating period of' said timed mechanism and visual means comprising a third dial and a pointer indicating the duration of the operating period.

15. In a thermostatic switching mechanism, in combination, a bimetallic element, condition control mechanism operated by said element, a lever associated with said bimetallic element, said lever comprising two pivoted members, each provided with a cam follower, a pair of cams each adjacent one of said cam followers, a pair of dials, each fixedly associated with one of said cams, a pointer, indicia on said dials indicative of temperature values, rotation of said dials serving to vary the position of said cams in accordance with the temperature value adjacent said pointer, a timed mechanism, means associated with said timed mechanism to juxtapose one ofl said cam followers to its associated vcam whereby the position of said lever and hence said bimetallic element is determined by one of said cams when said timed mechanism is operative and the other of said cams when said timed mechanism is inoperative in such manner that said element responds to one temperature for the duration of the period of operation of said timed mechanism and another temperature value subsequent to the termination thereof, and means for precluding the juxtaposition of one of said cam followers to its associated cam when the temperature value to which its dial is set is in excess of the temperature value to which the other dial is set.

16. In a device' of the character described, in combination, a base, a support movably carried by said base, a thermostat mounted on said support, a switch actuated by said thermostat, means biasing said support to a first predeterby said: base, a thermostat mounted on said support, a switch actuated by said thermostat, means biasing said support to a first predetermined position, manual means for moving said support to a second predetermined position, timing means, operation of said manual means putting said timing means in operation and predetermining the time required for the timing means to return said support to its iirst predetermined position, andmeans for individually adjusting said predetermined positions.

18. In a device of the character described, in combination, a base, a support pivotally carried by said base, a thermostat mounted on said support, a switch actuated by said thermostat, means biasing said support to a first predetermined position, manual means for moving said support to a second predetermined position, timing means, operation of said manual means putting lsaid timing means in operation and predetermining the time required for the timing means to return said support to its first predetermined position, a cover for said mechanism, means for adjusting one of said predetermined positions comprising a cam, and a dial for rotating said cam, part of said dial extending through a slot in the top of said cover so as to be capable of manual adjustment from outside of said cover.

19. In a device of the character described, a thermostat, control means actuated thereby, said thermostat being movably mounted whereby the temperature at which its actuates said control means may be varied, a first resilient means biasing said thermostat to aA first position, a second resilient means overpowering said first resilient means and biasing said thermostat to a second position, and means rendering said second resilient means inoperative for a predetermined period of time.

20. In a device .of the character described, a thermostat, control means actuated thereby, said thermostat being movably mounted whereby the temperature at which it actuates said control means may be varied, a first resilient means biasing said thermostat to a first position, a second resilient means overpowering said first resilient means and biasing said thermostat to mined position, manual means for moving 'said a second position, means rendering said second resilient means inoperative for a predetermined period of time, and means for varying at least one of said positions.

21. In a device of the character described, a thermostat, control means actuated thereby, said thermostat being movably mounted whereby the temperature at which it actuates said control means may be varied, a first resilient means biasing said thermostatto a first position, a. second resilient means overpowering said first resilient means and biasing said thermostat to a second position, means rendering said second resilient means inoperative for a predetermined period of time, and means for varying said predetermined length of time.

22. In a device of the character described, in combination, a condition responsive element, a control member actuated as a result of the response of said element to variations in the value of said condition, said condition responsive element being movable between first and second positions of adjustment, timing means operatively associated with said element for controlling its movement, said element' occupying said iirst position when said timer is inoperative, and manual means for rendering said timing means operative and causing said element to be moved lmember moimted on said base and actuated as( said second position and at nmetime thetimerequired theiimingxneanstocausesaidelementtobe returnedto said first predetermined position.

23. In a device of the character described, in culmination, a condition responsive element, a

`eontmlmenberxuztimtedasaresult ottherespense o! said element to variations in the value of said condition, said condition responsive element being movable between ilrst and second postuum of adjustment, timing means operatively associated with said element for controlling its movement, said element occupying said first pition when said timer is inoperative, manual annual meam ior varying at least one of saidumadeviceotthecharacterdescribedin arbase, a condition-responsive elementmovablymmmtedonsaidbase,acontrolu a result o! the response o! said element tol varia# tions in the value of said condition, said condiv means operatively associated with said `clment for controlling its movement.` said element occupying said nrst position when said timer is inoperative, manual means for rendering said timing means operative and causing said element to be moved to said second predetermined position and at the same time predetermlning thel time required for the timing means to cause said element to' be returned to said nrst predetermined position, manual me for varying at leastone o! said predetermin positions. a cover for said device, both o! said manual means extending outside said cover. means for visually indicating the manual adjustment of said one of said predetermined positions. and means for visually indicating whether or not said timer is operative and i! it is operative, how much time is required iorittoeamesaidelementtobereturnedto said ilrst position.

CARL G. KRONMIILER.

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