US2168545A

US2168545A - Control device

Info

Publication number: US2168545A
Application number: US104367A
Authority: US
Inventors: Daniel D Wile
Original assignee: Detroit Lubricator Co
Current assignee: Detroit Lubricator Co
Priority date: 1936-10-07
Filing date: 1936-10-07
Publication date: 1939-08-08
Anticipated expiration: 1956-08-08

Description

Aug. 8, 1939. I D. D. WILEI 2,163,545

CONTROL DEVICE Filed Oct, 7, 1936 INVENTOR BY 8M 8. 4 6

M A TTOR/VE) Patented Aug. 8, 1939 I UNITED STATES PATENT. OFFICE CONTROL nsvron Daniel D. Wile, Detroit, Mich assignor to Detroit Lubricator Company, Detroit, Mich., a corporation of Michigan Application October 7, 1936, Serial No. 104,367

16 Claims. (01. 62-4) My invention relates generally to refrigerating 1 comprises in general a refrigerant compressor apparatus and more particularly to control de- I, preferably driven by an electric motor 2, a revices therefor. frigerant evaporator 3 and a refrigerant con- One of the objects of my invention is to provide denser 4. The outlet of the evaporator 3 is con- 5 a new and improved control device for controlnected to the inlet of the compressor l bya return ling the operation of a refrigerating apparatus. line or conduit 5, and the outlet of the com- Another object of my invention is to provide pressor l is connected to the inlet of the cona control device having a power element and two denser 4 by a conduit 6. My c ntrol dev control means operatively connected to the power ignated in gen r l y the n m l h an 10 element in a new and improved manner to conlet that is connected to the inlet of the evapo- 10 trol the supply and admittance of a heat exrator I and has an inlet that is connected to the change medium to a heat exchanger. outlet of the condenser 4 by a supply line or con- Another object of my invention is to provide a duit 8. new and improved control device including a Referring nowvto the construction of my conthermostatic expansion valve and a switch opertrol device 1, shown in etail in F181 th 15 ated thereby to control respectively the admitvice includes a thermostatic expansion valve havtance and supply of-a refrigerant medium to a in a casing inclu n a hollow V v y refrigerant evaporator, and to provide a device provid d with n inlet II and n Outlet 1Jhe ofthis character in which the valve may actuate inlet ll being conn te to h nd n r 4 y 2Q independently of the switch means under certain the conduit 8 and the outlet I! being connected temperature conditions of the evaporator, to' the evaporator 3. Preferably the inlet H is Another object of my invention is to provide a in he form of a re, p ni g externally the control device of. the abovementioned character body at the lower end thereof and extending upin which range and differential adjusting means, w rdly nd lo in ly f the body. as h although acting on a common control means, are Within the body t and in r l W he side 25 each adjustable without aflecting the adjust- 'wal there f, adjace t the upper e d f nl b e ment of the other. ll, there is a wall portion l3 extending trans- Another object of my invention is to provide a v r e to r I l, and pe hr h heundercombination thermostatic expansion valve and side of the wall it there is a vertically extending switch for controlling a refrigerating apparatus bore l4 that communicates with inlet bore ll and to provide a device of this character having th ou h a ateral y extendi con ct b e a new and improved arrangement of the operat- Screw threaded into bore N there is a tubular ing parts thereof. shaped fitting or valve seat member l6 that pref- The invention consists inthe improved oonerably has a head I! for abutment with the unruetion and combination of parts, to be more derside of wall l3, and fitted in the lower end of fully described hereinafter and the novelty of member "there is preferably an insert member 35 which will be particularly-pointed out and dis- 8 havi an ape u e-th h ous p ovid a tinctly claimed. port and downwardly facing valve seat 19.

In the accompanying drawing, to be taken as The upper end of the y iii is p d s 40 a part of this specification, I have fully and preferably d fi e by a t u p d. upward- 40 clearly illustrated my invention, in which draw- 13 extending boss 20, and seated o t e upper ing v 1 end of the boss 20 andsealing the opening in the Figure 1 is a diagrammatic view of a refrigerupper end: f e b there is a be ows member ating apparatus and my new and improved devlc 2| that cooperate wi h h y t Pr vide an therefor; i expansible chamber 22 which is the low pres- 45 Fig. 2 isa view in central vertical cross secsure side of the valve. In the present instance, tion of my control device and taken along the the upper end of boss 20 is provided with an anline 2-2 of Fig. 3; nular slotor groove in which one end of the bel- Fig. 3 is.a plan view shown partly in cross seclows member 2| is positioned and hermetically tion and partlyin elevation taken along the line. sealed and secured to the boss 20- by sealing 50 3-3 1? Fig, 2, and means 23, which maybe solder. The bellows Fig, 4 is a view shown in cross section taken member preferably extends upwardly from the along the line 4-4 of Fig. 2. Y boss 20 and its upper or'free endis secured and Referring to the drawing by characters of ref hermetically sealed to a. movable end wall or erencefthe refrigerating apparatus-shownin Fig. plate 24 that is preferably cup-shaped having a 55' centrally disposed tubular portion that extends centrally through the bellows into the casing i3. Carried by the endwall of the centrally disposed portion 25 there is a U-shaped member or yoke 26, one arm b1 which is preferably rigidly secured to the bellows movable wall 24 by a rivet or post 21. The other, or lower arm of the yoke 26 has a valve member 28 rigidly secured thereto beneath the valve seat member l6, and the valve member 28 preferably has an upwardly directed conical face 29 for cooperation with the valve seat l3 to control flow therethrough. A carrier member 30 is preferably provided for the valve member 28, and preferably the bottom wall of the body i3 is provided with a threaded aperture to receive a tubular closure member 3| that slidably receives and guides the valve carrier member 33.

Mounted on the upper end of the valve body I3 and enclosing the bellows member 2| there is a tubular shaped spacer member 32, and mounted on the upper end of the spacer member 32 there is a casing 33.. The casing 33 and spacer member 32 are preferably formed of a suitable nonheat conducting material. The spacer member 32 may be screw threaded onto the boss 23 of the valve body l3 and preferably the valve body is formed having an upwardly facing annular shoulder below the upper end of boss 23 to provide a seating surface for the spacer member 32. The casing 33 is preferably of general rectangular shape having a top wall 34, bottom wall 35,

end walls

36, 31 and

side walls

38, 39, the side wall 33 being formed by a removable closure member or cover. In the casing bottom wall 35, adjacent end wall 36, there is an opening or aperture therethrough that is closed by the upper end of the spacer member 32. Preferably the upper end of the spacer member 32 positions in a recess in the casing bottom wall 35, around the opening therethrough, and abuts the recessed bottom wall. The casing and spacer member may be rigidly secured together by screws 33, or by other suitable means.

The post 21 that secures the yoke 26 to the bellows movable end wall 24 has an upwardly extending, externally threaded portion onto which is screw threaded an abutment member 43. In its upper end the abutment member 43 has a socket or bored recess 4| in which an end portion of a thrust member or pin 42 positions. Preferably the opposite ends of the pin 42 are pointed, or of conical form, and the recessed wall of the socket 4| preferably has an indentation or conical recess in which one of the pointed ends of the thrust pin 42 seats. The pin 42 extends through an aperture in an integral and internal transverse wall 44 of the spacer member 32, located adjacent the upper end thereof, and

the pin projects into the interior of casing 33. A removable wall means 46 is preferably interposed between the upper end of the spacer member 32 and the bottom recessed wall of casing 33, and is clamped therebetween and held in.

place by the screws 39. The removable wall 46 is preferably formed of a flexible and non-heat conducting material, such as rubber, and has an aperture therethrough for receiving the thrust member 42. Preferably the wall 46 has a downturned tubular portion 4'! around the opening therethrough to obtain a surface of suitable area for engagement by the pin 42, and this tubular portion 41 fits tight around the pin to form therewith a substantially fluid-tight connection; Surrounding the abutment member 43 there s 6 member 53 of plate-like form that preferably extends longitudinally of the casing adjacent the bottom wall thereof. The lever 53 is pivotally connected at one of its ends to the free end of a pivotally supported link member 5|, the pivotal connection between the lever and link members being at a point between the casing end wall 36 and the thrust member 42. The pivotal member 5| may be of plate-like form and may have downturned, spaced, substantially parallel side flanges 52 provided adjacent one end of member 5| with aligning apertures to receive a pivot pin 53 that may have its opposite ends secured in and to the casing side walls. The-side flanges 52 preferably extend beyond or past the free end of the link member proper, in the form of cars 54, and the lever 53 has spaced, downturned, substantially parallel side flanges 55 that may position between the ears 54, the ears 54 and flanges 55 having aligning apertures for receiving a pin 56 for pivotally connecting the pivotal link 5| and lever 53 together. The pivotal connection-between the lever 53 and link 5| provides a fixed pivot point at 53 and a movable pivot point at 56 for the lever 53, the purpose of which is hereinafter described. The lever member 53, between its free end and wardly facing socket 51, preferably of conical form,"-in .which the upper pointed end of the thrust member 42 seats, and the thrust member constitutes a movable fulcrum for the lever member 53.

The lever member 53. operatively connects the valve 26 and a thermostatic power element, designated in general by the numeral 63, and the lever 53 constitutes the movable member of a switch means that controls the operation of the compressor The thermostatic power element 63 includes a casing 6| that is preferably mounted on the topwall 34 of casing 33,the power element casing having an open side disposed toward and overlying an opening or aperture through the top wall 34. The power element casing 6| may be rigidly secured to the casing 33-by screws 62, or by other suitable means. Disposed within the power element casing 6|, adjacent its open end, there is a supporting member or wall 63 casing cooperate to provide an expansible chamber 61 which is connected to a temperature responsive bulb element by a conduit 65. The bulb element 66, conduit 63 and expansible chamber 61 provide a closed system which is charged with a temperature responsive, expansible-com tractible fluid which may be methyl chloride. The temperature responsive bulb 68 may be positioned in good heat transfer relation with a refrigerant evaporator, and is preferably located adjacent the evaporator outlet, as shown in Fig. 1.

An abutment member 18 is preferably carried by the bellows movable end wall 66 centrally thereof within the bellows, and the abutment member 18 preferably has a socket or recess in its lower end for receiving one end of a thrust member or rod 1|. The end wall of the socket or recess is preferably conical and the rod 1| preferably has a pointed or conical shaped end for seating therein. The lower end of the rod 1| is also preferably pointed for seatingin an upwardly facing socket 12 provided in the lever member 50 at a point between the movable pivot point 56*and the socket 51 for themovable fulcrum or thrust pin 42. A lower end portion of the thrust rod 1| is preferably threaded for receiving a nut 13, on the upper surface of which a plate-like abutment member 14 seats, the abutment member having a centrally positioned aperture therethrough for loosely receiving the rod 1|. Surrounding the rod 1| there is a coil spring 15 having one end abutting the abutment plate 14 and its other or upper end abutting the transverse wall 63, the spring being under compression acting to compress the bellows 65. It will be seen that the force exerted by the spring 15 to compress the bellows 65 may be varied or regulated by raising or lowering the movable abutment plate 14 by rotating the nut 13. As is well known, thermostatic expansion valves function to maintain a refrigerant evaporator completely refrigerated, and in this connection it has been found desirable to maintain the refrigerant at a super-heated temperature in a portion of the evaporator at the outlet thereof or where the bulb 68 is located. This super-heat temperature of the refrigerant may be regulated by regulating the force exerted by coil spring 15.

The lever 50, as previously mentioned, constitutes a movable switch arm and, in the present instance, the lever hasa downwardly extending extension member 16 rigidly secured to the lever adjacent its free end. The extension member 16 has a substantially horizontally disposed flange portion 11 that extends toward end wall 31, and carried by the lever 50 there is preferably a contact supporting member or metallic strip 18 that may be secured substantially midway of its ends to the flange 11, preferably by rivets. The supporting strip 18 carries a pair of spaced, upwardly facing contact members 80 that cooperate with a pair of spaced, downwardly facing contact members 8| to control the operation of the refrigerant compressor I. contacts 8| are each' preferably supported by a plate-like metallic terminal 82 that may project externally of the casing 33 through apertures in the casing bottom wall 35. Lines 83 and 84, Fig. 1, represent the main lead wires, wire 83 connecting to one terminal of the compressor motor 2 and wire 84 connecting to one of the terminals 82 of the switch. The other terminal 82 of the switch is connected to the compressor motor 2 by a lead wire 85.

Acting on the lever 50-there is a' yieldable means in the form of a coil spring 86 that opposes pivotal movement of the lever in a counterclockwise direction, as seen in Fig. 2, and thus the force exerted by the spring acts to

part contacts

80 and 8|. The spring 86 has one end,

The

or its lower end, abutting a movable plate-like abutment member 81, and the abutment member 81 preferably has a centrally disposed, downwardly facing socket or conical recess for receiving the pointed end of an upwardly directed, conical shaped, embossed portion 89 formed in the lever 50 between the free end thereof and the movable fulcrum pin 42. The other, or upper end of the coil spring 86 abuts a movable, plate-like abutment member 90 that is screw threaded 'onto an adjustment member in the form of a screw 9|. The adjustment member or screw 9| may be formed having an external annular shoulder 92 for abutment with the underside of the casing top wall 34 to prevent upward movement of the screw 9|, and may have a head projecting externally of the casing through an aperture in top wall so that the adjustment member 'will be readily accessible without removing the cover of casing 33. The movable upper abutment member 9|! is positioned for vertical movement longitudinally of the adjustment member 9| between two spaced

internal walls

94 and 95 of the casing 33, and these walls preferably extend across the width of the casing in substantially parallel relation to each other and to the casing end wall 31. The spaced

walls

94 and 95 may be integral with the casing side wall 38 and top wall 34, and depend from the top wall terminating above and spaced from the casing bottom wall 35. The opposed surfaces of

walls

94 and 95 are preferably formed having vertically extending ribs or keys 96, and the adjustable abutment member 9|] is provided withslots or keyways 91 in its, outer periphery in which the keys position to prevent rotation of the adjustable abutment erting a, force opposing movement of the lever 58 in a counterclockwise direction, as seen in Fig. 2, but which force is of insufl'icient magnitude to move the thrust member 42. The force exerted by range spring 86 determines the relatively high evaporator temperature at which the power element 68 will act to pivot switch arm 50 to closed circuit position, and the relatively low evaporator temperature at which the spring will overcome the power element and pivot switch arm 58 to open circuit position. Or in other words, the spring 50 determines the temperature range of operation of the switch means and will therefore be hereinafter referred to as the range spring. By means of the adjustment member 9| it will be seen that the force exerted by spring 86 may be changed or regulated as desired, and that by so doing the temperature range of operation of the switch arm 50 may be raised or lowered as desired, but it will be understoo'd that raising or lowering the range of operation of the switch does not change the temperature differential between the temperature at which the switch is closed and the temperature at which the switch is opened. For example, if the adjustment member is rotated to place the range spring 86 under a greater compression force, it will then be required that a correspondingly higher evaporator temperature be reached before the power element will overcome spring 86 and pivot switch 50 to closed circuit position to start the compressor I, However, raising the cut-in temperature of the compressor also raises the cut-out temperature, or temperature at which the spring 86 will pivot switch 50 to open position, by a like number of degrees, so that raising or lowering the temperature range of operation of the switch will not change the temperature differential between opening and closing of the switch. The lower spring abutment member 81 is formed having spaced, oppositely disposed, down-turned flanges 9! the lower edges of which are positioned,to engage the upper surface of the casing bottom wall 35 to limit downward movement of abutment member 81.

The temperature diiferential of operation of the swltchmeans, and therefore the compressor I, is determined by a helical coil spring 98 acting on the free end of lever 50. The lever 50, in the present instance, has an oifset or laterally disposed end portion 99 disposed toward the casing cover 39, and the end of the offset portion is preferably pointed for seating in a socket of a plate-like abutment member I against which one end of the differential spring 98 abuts. The other end of spring 98 preferably abuts a platelike abutment member ml, and screw threaded into the casing end wall 31 and projecting into casing 33 there is an adjustment member in the form of a screw I02, the inner end of which is preferably pointed for seating in a centrally disposed socket in the abutment-member IOI. When the contacts 80' and BI of the compressor controlling switch are in closed circuit position, as shown in Fig. 2, the axis of the differential spring 98 may be in horizontal alignment with lever 50, longitudinally thereof, but when the lever is pivoted in a clockwise direction the point of engagement between the free end of the lever and the spring abutment member I00 is moved downward past center, the spring force being increased and its direction changed so that the spring force acts to aid range spring 86 to pivot lever 50 in a clockwise direction, as seen in Fig. 2, and hold contacts 80 in open circuit position. Thus the spring 98 exerts a force opposing the power element and acting to hold the switch in open circuit position. By means of the adjustment member I02 the force exerted by differential spring 98 may be regulated to change the temperature differential of operation between opening and closing of the switch 50. For example, if the force exerted by spring 98 were increased, the evaporator temperature at which the power element would overcome

springs

86 and 98 to close switch 50 would be increased correspondingly.

The wall 94 depends below the lower end of wall 95 and in the side thereof facing wall 95 there is a pair of spaced, V-shaped notches or recesses providing fulcrum points or seats in which the pointed ends of a pair of spaced, substantially parallel arms I04 of a lever I05 seat, the arms I04 straddling the range spring 86. The lever I05 is disposed within casing 33 above the lever 50 and extends longitudinally of the lever 50. The lever I05 has an extended portion I06 extending toward the casing end wall 3'1, the end of the extended portion I06 preferably being pointed to seat in a socket of a plate-like abutment member I01 against which one end of a helical coil spring I08 abuts. The other end of the spring I08 abuts a plate-like abutment member I 09 that has a socket in which the pointed end of an adjustment screw IIO seats, the screw being screw threaded into the casing end wall ST.

The point of engagement of the lever I05 and the spring abutment member I 01 is above the ful-' crum points of the lever arms I04 v so that the spring I08 and lever I05 constitute a toggle or overcenter device. Pivotal movement of the lever I05 in a counterclockwise direction is limited by engagement of the lever with the lower end of the internal wall 95. Carried by the lever I05 and depending therefrom is an abutment member III positioned so that its lower end wall engages lever 50 upon predetermined pivotal movement of lever I05 in a clockwise direction to pivot lever 50 and part contacts 80 and'8I. Preferably the lever 50 is formed having an upwardly directed embossed portion H2 providing a rounded surface for engagement with the lower end of member III to reduce friction therebetween. The lever I05 is normally held in its ra sed or' inactive position, out of engagement with lever 50, by the coil toggle spring I08 which, acting at an angle, holds the lever I05 in'abutment with its stop.

The lever I05 may be pivoted, and the toggle point moved overcenter, by a manually operable plunger member II3 of rod-like form which may be positioned to engage the lever I05 preferably adjacent its free end. The casing top wall 34 may be provided with a vertically extending aperture therethrough for slidably receiving the plunger member H3, and the member I I3 projects externally of the casing 33 and preferably has a head H4 on its upper end. Adjacent its lower end, within casing 33, the plunger member H3 is formed having a portion of reduced diameter, as at H5, providing opposed, substantially horizontally disposed, parallel annular shoulders H6 and Ill between which an edge portion of the. lever I05 positions and is engageable by one or the other of the shoulders. By pushing the plunger member H3 downward the

switch contacts

80 and 8! may be parted to stop the compressor I when it is desired to defrost the refrigerant evaporator. When the plunger member H3 is pushed downward, the point of engagement between the lever I05 and abutment member I01 will be moved overcenter and the force exerted by spring I08 will then be directed to hold the lever in its down position. When the plunger H3 is pushed downward, the switch arm 50 is moved out of engagement with the range spring abutment member 81 after the abutment member engages the casing bottom wall 35, and the purpose of disengaging the switch arm from the range spring 86 is so that the defrost cut-in will be independent of the range spring.

The operation of my control device in connection with a refrigerating apparatus is as follows: With the parts in the positions shown, the compressor I is in operation and the expansion valve 28 is in open position being throttled in accordance with the refrigerant pressure acting on the bellows 2| and the opposing pressure exerted by the power element to maintain the evaporator 3 completely refrigerated. As the apparatus continues in operation the temperature of the evaporator will gradually decrease with the result that the pressure exerted against the bellows 2|, and the opposing pressure exerted by the fluid against the power element bellows 85 will decrease. During this operation the force exerted by the power element 60 is sufllcient to overcome the opposing forces and hold lever 50 in position to hold connot cause the

contacts

80 and 8| to be parted, forthe lever 50, will move bodily or pivot about its movable pivot point 56, which movement will compensate for the movement of thrust pin 42. When the temperature of the evaporator, at the point of location of bulb 68, decreases to the predetermined desired temperature, the force exerted by the range and differential springs will pivot lever 50 in a clockwise direction, as seen in Fig. 2, and move contacts 80 out of engagement with contacts 8I to stop the refrigerant compressor I. Downward movement of the range spring 86 is limited by engagement of its lower abutment member 61 with the upper surface of J the casing bottom wall 35. When lever 50 is pivoted to

part contacts

80 and 8|, the force exerted by the differential spring 98 acting on the lever is increased due to the change in-the angle at which it acts on the lever, but the force exerted by the spring 98 is not suflicient to move the lever out of engagement with the range spring abutment member 81. When the compressor stops, the pressure exerted by the refrigerant will increase in the valve chamber and acting on the bellows 2| will expand the same to seat valve member 28. temperature and therefore the pressure of the refrigerant medium in the evaporator will increase, and when the evaporator temperature at the bulb element 68 reaches a predetermined temperature the force exerted by the power element 60 will pivot lever 50, on the valve thrust member 42 as a fulcrum, in a counterclockwise direction, as seen in Fig. 2, and move contacts 80 to closed circuit position to start the refrigerant compressor I. By adjusting the range spring 86 the minimum or low evaporator temperature at which the compressor will be stopped may be selected. 7

When it is desired to defrost the system the control plunger I I3 is moved downward, which will move the toggle point of the lever I05 and spring I08 downward overcenter. The depending abutment member III will engage lever 50 and pivot the lever in a clockwise direction, the spring abutment member 81 following the lever downward until the abutment member engages the casing bottom wall 35, but the lever 50 will be thereafter pivoted away from the abutment member 81 until the lever engages the bottom wall of the casing. The lever 50 is held in its down position and the contacts 80 carried thereby in open circuit position by the spring I08 and the differential spring 98, that is, independently of range spring 86 so that the defrosting temperature will be maintained constant irrespective of adjustment of the range spring? When the temperature at the evaporator has increased sufficiently to assure defrosting of the evaporator, then the pressure exerted by the power element 60 on lever 50 will overcome the force of spring I08 and the force of differential spring 98 and pivot lever 50 on the thrust pin 42 in a counterclockwise direction into engagement with the range spring abutment member 81. The downwardly directed force of the toggle spring I00 and differential spring 98 will decrease as the lever 50 is pivoted in a counterclockwise direction, or toward closed circuit position, and the force exerted by the power element 60 will be sufllcient to overcome the range spring 86 and pivot lever 50 upward to move the contacts 80 into engagement with contacts 8| to start the compressor I. Upward movement of lever 50 to closed circuit position will move the togglejpoint of the spring I08 and lever I05 overcenter, and the toggle spring will pivot lever With the compressor I stopped, the

I05 to, and hold the lever in its normal position out of engagement with lever 50.

From the foregoing description it will now be seen that I have provided a new and improved control device having a switch for controlling operation of' a refrigerant supply means and a valve controlling admittance of the refrigerant to an evaporator operated by a single temperature responsive power element in a new and improved manner. It will further be seen that the thermostatic expansion valve actuates the switch controlling the compressor I without such operation interferring with the normal operation of the expansion valve. In addition, I have provided a refrigerating apparatus control device in which throttling action of the thermostatic expansion valve will not open the switch controlling the compressor. Furthermore, I have provided a control device having range and differential adjustment means acting on a common controlling means, and one in which the defrosting mechanism operates independently of the range determining means when automatically cutting-in the refrigerant compressor.

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

l. A control device for a refrigerating apparatus having a refrigerant evaporator and a refrigerant medium supply means therefor comprising, a thermostatic expansion valve operable in response to the temperature of the evaporator for controlling the admission of the refrigerant medium thereinto and including a power element, control means controlling the operation of, the refrigerant medium supply means, and a lever member operatively connecting said power element and said control means, said power element acting through said lever member to actuate said control means.

2. A control device for a refrigerating apparatus having a refrigerant evaporator and a refrigerant medium supply means therefor comprising, means for controlling said supply means, a valve controlling admittance of the refriger ant medium into the evaporator, means respon- I slve to the temperature of the evaporator for actuating said valve and said controlling means, and a lever member operatively connecting said valve, said responsive means and said controlling means.

3. A control device for a refrigerating apparatus having a refrigerant medium evaporator and a refrigerant medium supply means therefor comprising, means for controlling the operation of the refrigerant medium supply means, a valve for controlling the admittance of the refrigerant medium into the evaporator, power means responsive to the temperature of the evaporator for actuating said valve and said control means, a thrust member operatively connecting said valve and said power means, and a lever member fulcrumed on said thrust member and operatively connecting said power means to said control means, said lever member acting to .transmit movement from said power means to said valve.

4. A control device for a refrigerating apparatus having a refrigerant medium evaporator and a refrigerant medium supply means therefor, comprising means for controlling the operation of the refrigerant medium supply means, valve means for controlling admission of the refrigerant medium to the evaporator, power means responsive to the temperature of the evaporator and operable to actuate said valve means, a lever member operatively connecting said power means to said control means and to said valve means, yieldable means engageable with said lever member to oppose operation of said control means, and a second yieldable means engageable with said lever member to oppose operation of. said control means, said second opposing means acting on engagement with said lever member to disengage said lever member from said first-named opposing means.

5. A control device for a refrigerating apparatus having a refrigerant medium evaporator and arefrigerant medium supply means therefor comprising a supporting means, control means for controlling the refrigerant medium supply means, a valve for controlling the admittance of the refrigerant medium into the refrigerant evaporator, a thrust member for said valve member, a lever member operable for actuating said control means and fulcrumed onsaid thrust member, a pivotal link member pivotally supported by said supporting means and pivotally connected to said lever member, and a temperature responsive power element responsive to the temperature of. said evaporator and acting on said lever member to actuate said valve and said control means, said power element exerting its force on said lever member at a point between said fulcrum and the pivotal connection of said link member to said lever member.

6. A control device for a refrigerating apparatus having a refrigerant evaporator and a refrigerant medium supply means therefor comprising a casing, a reciprocal valve member in said casing for controlling flow of refrigerant therethrough into the evaporator, said casing having an opening in a wall thereof, a second casing mounted on said first-named casing and closing said opening, a reciprocal thrust member for said valve member and extending through said opening into said second-named casing, switch means operable for controlling the refrigerant supply means, a lever member in said second-named casing and pivotally movable on said thrust member, said lever member being operable to actuate said switch means when said lever member is pivoted about said thrust member as a fulcrum, a temperature responsive power element mounted on said second-named casing and having a thrust member engaging said lever member at a point between said fulcrum and one end of said lever member to pivot said lever member about said fulcrum and to actuate saidvalve member, and a link member pivotally supported by said second-named casing and pivotally connected to said one end of said lever member so that said power element can actuate said valve member without transmission of. such movement to said switch means.

'7. A control device for a refrigerating apparatus having a refrigerant evaporator and a refrigerant medium supply means therefor comprising, a reciprocal valve structure including a valve for controlling the admittance of the refrigerant medium into said evaporator, control means for controlling the operation of the supply means, a lever member pivotally and bodily movable and supported on said valve structure, said lever member acting on pivotal movement to actuate said control means, said lever member acting on bodilymovement to actuate said valve structure without actuation of said control means, and a thermostatic power element for moving said lever member.

8. A control device for a refrigerating apparatus having a refrigerant evaporator and an electrically operated refrigerant supply means therefor comprising, a reciprocal valve structure including a valve for controlling the admittance oi the refrigerant medium to the evaporator, a contact member, a lever member fulcrumed on said reciprocal valve structure and cooperable with said contact member to control the operation of the supply means, said lever member being arranged to pivot in one direction relative to said valve structure to open the circuit of the supply means and to pivot in the opposite direction relative to said valve structure to close the circuit of the supply means, a power element responsive to the temperature of the evaporator, said power element having a thrust member engaging said lever member at a point offset from said fulcrum and on the opposite side of the fulcrum from said contact member, said lever member being pivoted by said power element in said opposite direction to close the circuit of the supply means and being movable with said valve structure on operation thereof by said power element to prevent opening of the circuit of the supply means, and yieldable means acting on said lever member and determining the closing of the circuit to said supply means by said power element.

9. A control device for controlling a refrigerating apparatus having a refrigerant evaporator.

and a refrigerant supply means therefor comprising a supporting means, a valve for controlling the admittance of refrigerant into the evaporator, control means controlling the operation of the supply means, a power element for actuating said valve and said control means, a lever member operatively connecting said power element, said valve and said control means, a:

helical coil spring acting to move said lever member to actuate said control means, and a toggle device for moving said lever member and for holding said lever member in one position, said toggle device having an active position and an inactive position and including a lever member overlying and extending longitudinally of said first-named lever member, said secondnamed lever member having a bifurcated end straddling said coil spring and fulcrumed on said supporting means.

10. A control device for a refrigerating apparatus having a refrigerant evaporator and a refrigerant medium supply means comprising, a control means for starting and stopping operation of said supply means, means determining the temperature range of operation of said control means, means determining the temperature differential of said control means, means operable to establish a high temperature limit above said range, and means cooperable with said range determining means upon operation of said last-named means to disconnect said control means and said range determining means.

11. In a control device for a refrigerating apparatus, a controlling means including a movable member, temperature responsive means operable to actuate said controlling means, means acting on said responsive means and determining the normal temperature range of operation of the apparatus, adjustment means cooperable with said opposing means to raise or lower the temperature range, releasable means operable to move said member to raise the high temperature limit to a defrosting temperature and to hold said member against movement by said responsive means at temperatures below said defrosting temperature, and means operable on movement of said member. by said last-named means to render said second-named means ineffective to act on said responsive means so that a constant defrosting temperature will obtain irrespective of raising or lowering of the normal temperature range.

12. In a control device for refrigerating apparatu's, switch means including a movable member movable to open and close a circuit to control operation of the refrigerating apparatus, temperature responsive means operable to move said movable member in one direction, means operable to move said movable member in the opposite direction and cooperable with said responsive means to determine a normal temperature range of operation of the refrigerating apparatus, adjustment means operable to raise or lower the temperature range of operation of the refrigerating apparatus, means operable to move said movable member to stop operation of the refrigerating apparatus, yieldable means operable on movement of said movable member by said last-named means to hold said member in open circuit position, said yieldable means also being operable on movement of said movable member by said last-named moving means to oppose movement of said movable member by said responsive means to raise the high limit of the temperature range to a desired defrosting temperature, and means to render said secondnamed moving means ineffective on movement of said movable member by said last-named moving means so as to obtain said desired defrosting temperature irrespective of adjustment of the normal temperature operating range.

13.'In a control device for refrigerating apparatus, switch means to control the refrigerating apparatus, temperature responsive means operable to actuate said control means, spring means operable to determine the temperature range of operation, means to adjust the force exerted by said spring means to raise or lower the temperature range, an abutment member for said spring means and engaging said switch means at temperatures within the said temperature range, overcenter means having an active and an inactive pqsitlon: and operable when moved to its active position to move and hold said switch means in open position and oppose opening of said switch means by said responsive means, said overcenter means being movable at a predetermined temperature to its inactive position by said responsive means, stop means for limiting movement of said abutment member prior to limitation of movement of said switch means to render said spring means ineffective, and manually operable means to move said overcenter means to its active position.

14. In a control device for refrigerating apparatus, switch means to control the refrigerating apparatus, temperature responsive means operable to actuate said control means, spring means operable to determine the temperature range of operation, overcenter means having an active and an inactive position and operable when moved to its active position to move and hold said switch means in open position and oppose opening of said switch means by said responsive means, said overcenter means being movable at a predetermined temperature to its inactive position by said responsive means, and manually operable means to move said overcenter means to its active position.

15. In a control device for refrigerating apparatus, a casing having an opening in a wall thereof, an actuated member on one side of said wall, an actuator on the other side of said wall, a thrust member extending through said opening and operatively connecting said actuator and said actuated member, and a flexible-closure member closing said opening and having a resilient tubular portion through which said thrust member extends, said tubular portion being circumferentially stretched over said thrust member and held tightly thereto by the contractional force of the resilient material under tension.

16. A control device for a refrigerating apparatus having a refrigerant evaporator and a refrigerant medium supply means comprising, a control means for starting and stopping operation of said supply means, means exerting a force on said control means and determining the high and low limits of temperature range of operation of said control means, and means operable to eliminate the force of said range determining means acting on said control means and operable to raise the high limit of temperature range to provide for defrosting of said evaporator.

DANIEL D. WILE.