US2177480A

US2177480A - Control system for refrigerators and the like

Info

Publication number: US2177480A
Application number: US130311A
Authority: US
Inventors: Edwin G Gaynor
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-03-11
Filing date: 1937-03-11
Publication date: 1939-10-24
Anticipated expiration: 1956-10-24

Description

Oct. 24, 1939. E. G. GAYNoR 2,177,480

CONTROL SYSTEM FOR REFRIGERATORS AND THE LIKE Filed March ll, 1937 2 Sheecsf-Shveell l INVENTOR ATTORNEYS.

DEFRosTxNG DEFRosTlNG l Oct. 24, 1939. E. G. GAYNoR 2,177,480

CONTROL SYSTEM FOR REFRIGERATORS AND THE LIKE Filed March 11. 193'7 2 Sheets-Sheet 2 ATTORNEYS Patented Oct. 24, 1939 UNITED sTATEs I CONTROL SYSTEM FOR REFRIGERATORS AND THE LIKE Edwin G. Gaynor, Fairfield, Conn.

Application March 11,

19 Claims.

This invention relates to refrigerating or cooling systems and the like and thermostatic units adapted for use therewith.

In refrigerators it is important to keep the y evaporator cooling unit as free as possible of frost or ice for the reason that this layer or coating of frost or ice acts as lan insulator and reduces the efficiency of the refrigerator.

The household refrigerators now in use generally operate in about a ten degree range which is set at the factory. This range may be set for say to 25 F. and the owner ofthe refrigerator .can manually set where that 10 F. shall be, for instance, if a colder refrigerator is desired the regulator can be manipulated so that the 10 F. range extends from 6 F. to 16 F. but this range being be1ow 32 F. during operation of the device. exterior Wall of the evaporatorl As the evaporathe frosting of the evaporator is unavoidable.

A device embodying my inventionis provided with means whereby the refrigerating system may operate to defrost the evaporator on each cycle. I can regulate my thermostatic unit to obtain a seventeen to twenty degree range as distinguished from the ten degree range heretofore described, the upper limit being between about 33 F. to 36 F. or above the freezing point of water, and the lower limit being between about 13 F. to 16 F. so that continuous defrosting cycles are obtained. That is, during one cycle, any accumulated frost or ice layer is melted off the evaporator and then the refrigerator is cooled down to a relatively low temperature so that the average box temperature is well under 40 F. Such cycles are continuously repeated so that a continuous defrosting is obtained and substantially no accumulation of frost or ice' is obtained. In this way humidication of the interior of the refrigerator is obtained. By having a large range of temperatures better ventilation of the refrigerator is obtained because the air in the refrigerator expands and contracts to a greater extent.

If freezing temperatures are desired for freezing ice cream, desserts, etc., or for any other reasons, or if colder temperatures are desired, the defrosting cycle is temporarily eliminated and the thermostatic unit is set to function within a ten degree range, such as, 12 F. to 22 F., 10 F. to 20 F. etc. If desired, the defrosting cycle can later be turned on again.

To get the defrosting cycle and to start the refrigerator, the control handle is turned from off to the rst position. Turning the control handle further in the same direction causes the device to function to produce lower temperatures 65 but without obtaining defrosting. The device is 1937, serial No. 130,311

very sensitive and positive in its action and can be adjusted to accurate temperatures,

Furthermore, according to my invention `I have eliminated conventional snap movement, throw over, mercury or other electrical switch mecha- 5 nisms and in place thereof I use electrodes or contacts one of which is positively and slowly moved towardor away from the other afterV a lapse of time or dormant period of the action of the controlling member upon the contacts in 10 closing and opening the motor circuit without teetering and with negligible arcing. 'Ihese contacts are controlled by a thermostat comprising a charged bellows member connected with a tube having a closed end. The closed end of the tube 15 is preferably placed in contact with the bottom tor warms up, the volatile liquid in the bellows member and tube evaporates and expands and moves the bellows member to close the contacts. 20 When the evaporator cools, the volatile liquid condenses and contracts and the bellows is contracted to separate the contacts. The bellows member A, responds to changes in volume and actuates the electrodes or contacts in this way.

I have also provided a. construction which can be adjusted at the factory for the so-called factory adjustment by reducing the volume of the methyl chloride vapor space without increasing the pressure on the methyl chloride vapor.

Instead of bellows otheftemperature responsive means may be employed.

Other advantages and features of my invention will be hereinafter pointed out.

In the drawings:

Fig. l represents an enlarged longitudinal section of a thermostatic unit adapted for use in controlling a motor circuit for a refrigerator compressor or the like;

Fig. 2 represents a front elevation of the ther- 40 mostatic unit with parts removed to facilitate the disclosure;

Fig. 3 represents a View similar to Fig. 2 showing the control handle in another position;

Fig. `4 represents the positions of the parts 45 when contact is made between the electrodes or contacts;

Fig. 5 represents the position of the partsy when the contact is broken; and

Fig. 6 represents the position of the parts with 50 the thermostatic unit set for the defrosting cycles and the electrodes or contacts in abutment.

Referring now to the drawings, the reference character l0 designates a small tube with its bulb Il preferably placed in contact with the 55 lio bottom exterior wall of the evaporator or cooler of a` refrigerator. However, the bulb may be placed against the exterior wall of the evaporator or cooler at any suitable place. This tube contains methyl chloride. Other fluids may be used in place of methyl chloride but methyl chloride is preferred by me. The tube III is securely held and sealed within plug I2 having opening I4 therein. The plug I2 is secured to one end of the cylindrical housing I6 in any suitable manner as by a nut I8. This plug has a' flange 20 within the housing, to which one end of the bellows 22 is attached by soldering or other suitable means. The other end of the bellows 22 is secured to the rim 24 of a cup 26 by soldering or the like. This cup extends into the bellows but the bottom 28 thereof is spaced from the plug I2 as at 30. By this construction a closed space for the methyl chloride is provided extending between the inner walls of bellows 22 and the exterior of cup .26 and further by using this cup and construction there is space made available for mounting some of the elements thereby reducing the size of the control.

An adjustable cup-shaped member 32 is mounted within the housing and has a rolled thread 34 which is screwed into rolled thread 36 on the housing for adjustment purposes, later to be described. 'I'he housing I6 has a slightly larger diameter at one side of thread 36 at 31 to permit insertion of member 32.` The adjustable member has openings 38 to receive a tool for adjusting the position of the member. A main spring 40 is held between the base member 4| in the bottom of the cup 26 and the depressed portion 42 of the member 32. As the methyl chloride is vaporized, a pressure is created and the spring 4 0 counterbalances this pressure and the spring is so proportioned that the bellows elongates a lcertain length for each degree rise in the temperature of the evaporator or vice versa. 'Ihe spring reduces the amount of movement of the bellows due to temperature changes. In this form of my invention the spring selected permits the bellows to move about .01 of an inch for every degree change 1n temperature of the evaporator in the refrigerator but I am not to be restricted to this calibration. When the foregoing or denite counterbalancing of spring and bellows is determined for a given movement per degree in temperature, then a relation corresponding to any desired lapse of time or length of cycle can be had by fixing the amount of slack between operated and operable members.

The movements of the bellows to open and close the contacts and. the mechanism between the bellows and the contact 44 moved thereby Will now be described. This contact is preferably hollow and has its rear end 46 spun over washer 48 secured to the one end of a pin 50. This pin exteds through an opening 52 in member 32. At i other end the pin is provided with a head or abutment 54 which is mounted in the enlarged portion56 of a tube 58. 'I'he enlarged portion 56 intermediate its ends has a shoulder 60 and a fixed ring 62 which cooperate with the head or abutment 54 on the contact 44 to actuate the contact. The shoulder 60 functions to close the contacts when the system is not on the defrosting cycle and the ring 62 always functions to separate the contacts either when the system is operating on the` defrosting cycle or the 10 F. range. It is to be noted that the distance between shoulder 60 and ring 62 is greater than the thickness of the abutment 54 so that a lost motion connection is provided between

parts

60 and 62 and abutment 54. In this way a definite and known temperature lapse is provided between making and breaking the circuit when the device is not operating on the defrosting cycle. The ring 62 is held against ledge 64 on enlarged portion 56 by spinning over the metal of the tube as at 66.

The tube 58 at its other end has an inwardly directed annular flange 10 which is normally held against the piston 'I2 on rod 14 by spring 16 smaller than spring 40 and which abuts against the llange 11 of the enlarged portion 56 on tube 58 and the base member 4| attached to rod 14 on piston 12. When the thermostatic unit is adjusted for the ten degree range and not on the defrosting cycle, the

parts

14, 12 and 56 act as a unit as if they were rigidly connected together and shoulder 60 will abut head 54 and move contact 44 against the other contact to complete the circuit and start the compressor upon expansion of the bellows, and ring 62 will abut and move head 54 to open the circuit upon contraction of the bellows. When the thermostatic unit is adjusted for the defrosting cycle. the end portion 66 of the enlarged portion 56 is stopped by member 32 before shoulder 60 moves contact 44 against the other contact and further expansion of the bellows' is obtained and then relative movement starts between piston 12 and enlarged portion 56 against the action of spring 16 until piston 12 is moved a sufiicient distance by the bellows so that it pushes abutment 54 and moves contact 44 against the other contact to complete the circuit and start the compressor. The base member 4| has a round block 82 for centering the bottom of spring 16. The exterior bottom wall of cup 26 has a plurality of projections 84 for preventing blocking .of the passage I4 in plug I2.

The contacts and their supporting means will now be described. The contact 44 during the operation of the apparatus is positively and slowly moved toward and away from the other contact in substantially a straight line during a portion of the movement of the bellows and is dormant during another portion of the movement of the belows. This is true because there is no positive connection between head 54 and shoulder 60 and ring 62. The contact 44 has a head 86 provided with a depression 88 therein. A convex disc 90, preferably of silver, is held in the depression 88 by spinning over the end of the contact as at 92 and is so mounted as to leave a space 94 behind the disc 90. The other contact 96 has a convex disc 98 preferably of silver, which is mounted thereon in a way similar to the mounting of disc to leave a space |00 behind the disc 98. The

contacts

44 and 96 are mounted in a tubular member |02 formed of a conducting tube |04 and a non-conducting tube |06 of the saine internal diameter. The contacts are so mounted as to have a sliding t with the tubular member. Springs |01 are provided for contact 44 so vthat the contact is held in the position to which it is moved and cannot readily vibrate or move out of place. These springs are elongated and have their one endportion |08 held between tube |06 and a hollow screw member |09. At their other ends the springs are bent as at ||0 and these bent portions extend through open ings in tube |04 and are forced against the inclined or conical surface ||2 of contact 44 so that if there is any movement due to jarring of the device, the springs will force contact 44 toward rather than away from contact 96.

Tube |06 and a part of tube 04 are mounted in the hollow screw member |09. lI'ube |06 is secured to member |09 by spinning the end of the screw member as at I |3 over the shoulder ||4 on the tube |06 whereby the tube |06 and screw member turn as a unit. The screw member |09 is screwed into a head ||5 mounted on annular shoulder ||6 formed on housing I6. The head is formed of insulating material. Contact 96 is provided with an elongated rod I8 which extends through o-pening |20 in the end of tube |06. The rod is of a smaller diameter than the internal diameter of the tube so as to provide a space |24 between the rod and the tube. Positioned within this space isa spring |26 which abuts a bushing |21 at the inner wall of the tube at one end and at its other end abuts the contact 96 so as to provide a resilient mounting for contact 96. When the evaporator is warming up there will be a thermal lag after contact is made and expansion of the bellows will continue for a short time before cooling is obtained in the refrigerator and this additional expansion moves contact 96 to the right in Fig. l against the action of the spring |26. This movement due to the thermal lag is used to hold the electrodes or contacts in rm contact. The outer end of the rod is screw threaded to receive a nut |28 which has an annular groove |30 to receive an electric wire |32. This forms a part of the circuit for leading current to contact 96.

The screw member |09 is threadedly mounted within the head ||5 so as to be adjustable to various positions. By means of screw member |09 the position of contact 96 may be moved to defrosting position or to the other positions for obtaining low temperatures in the refrigerator. When this screw member |09 is rotated and moved to different positions the contact 96 and contact 44 are both normally moved. However, if the member |09 is moved such a distance that ring 62 on enlarged portion 56 stops movement of contact 44, the other contact 96 will continue to be moved by the screw member until it reaches the position desired. In Fig. 1 of the drawings it will be seen that this screw member surrounds tube |06 and a part of tube |04 and that the springs |01 also function to hold the tubular member and tube together as a unit. In Fig. l the contact parts are shown in about the 16 to 26 F. position for the refrigerator with the screwV member screwed out nearly as far as it will go. When it is desired to lower the range from the one represented by the showing in Fig. 1 to a lower range, the screw member is' rotated to screw the member in toward the cup 26 and the connected parts are moved inwardly together as above set forth. During this movement contact 44 will also be moved, unless of course, the abutment 54 strikes the shoulder 60 on the enlarged portion 56. If this occurs and the movement of contact 44 is stopped, the other contact 96 will be moved relatively to Contact 44.

A slotted dust cover |36 is mounted on the one end of the device to cover the operating mechanism. The cover has an annular flange |38 for fitting over flange |40 on the housing i6. Openings |42 are provided in the flanges for receiving screws or other fastening means for fastening the device in position on a refrigerator or the like.

A slot |44 is provided for a` control handle |46. Indications for the various positions of the handle may be provided. I preferably provide an indentation not shown for locating the handle for defrosting position. Indentations may be respectively provided for the 26 to 16 degree range and for the oli position, and the handle may have a projection for cooperating with these indentations. In Fig. 2 the arrow |50 shows the direction of operating the handle to obtain colderpositions. 'Ihe control handle is formed of insulating material.

The control handle |46 and the electrical connections will now be described. The handle has a hexagonal opening |52 of substantially theifwith the strip |60 is another arcuate metal strip |62Isecured to head |5 by meansA of a screw |64. When the handle is in olf position the strips are separated but the strips form parts of a circle so that the strips contact when the handle is moved to on position. Strip |62 has a bent portion |66 extending over the central portion of the handle and an upwardly bent end |68 which permits strip |60 to slide under contact |62 to make contact.

The current passes through wire |10, through screw |64 and contact 62. When the flat strips are in contact, the current then passes through strip |60, screw |58, wire |32, rod ||8 and then to contact 96. When

contact members

96 and 44 are in contact, the current passes through contact member 44, through springs |01, and tube |04 to brush or ring |12 and passes through the screw |13 in head ||5 and out through wire |14. The brush or ring |12 surrounds and is in contact with screw member |09.

My

contacts

44 and 96 are operated without snap movement switches which have heretofore been believed absolutely essential. Certain conditions however are necessary to prevent arcing.

The arc space is considered as filled with stream' ers of positive and negative ions, which, if recombined or one or the other displaced to a fair4 extent, will leave the space with a high dielectric strength and this space will not reignite after the voltage has built up following its half cycle zero. I prefer to hollow out the insides of the contacts or electrodes adjacent their meeting or abutting ends. By making the contacts or electrodes hollow, the path of the current is generally at right angles to the path across the arc space and the magnetic field set up pulls the more mobile negative ions from that space.

The contacts or

electrodes

44 and 96 are so proportioned and moved as to minimize any arc restriking between the ends of the contacts or electrodes. These contacts or electrodes are effective, dependable, cheap to manufacture and have a long life. In the preferred form electrodes-44 and 96 are in coaxial arrangement-but other arrangements may be used provided the electrode 44 is moved slowly and positively in substantially a straight line movement when it is moved.

The adjustable member 32 provides means for adjusting the unit at the factory. If, for example, it is found that with contact 96 set in a definite position, contact Il met it at 15 F. and in this position it is desired to have the contacts meet at 25 F. and it is not possible to alter the position of contact 96, by sc're'w member |09, then member 32 is screwed down toward the bottom of housing I6 and against the action of spring 4D. The cup 26 is moved down an amount equal to the amount of longitudinal movement of member 32 without increasing the pressure in the system. The methyl chloride vapor is near its condensation point and when the member 32 is screwed down there is a temporary increase in pressure but this increase is suihcient to condense some of the methyl chloride vapor and the resulting pressure remains the same as the original pressure at the same elongation of spring 40, In this Way the cup 26 still rises or falls .010 inch per degree change in temperature of the vapor in the bellows and a depression of the disc by .100 inch will cause the contacts to meet at 25 F. instead of 15 F. and it will be noted that in this movement the elongation of the spring was not changed and any change in the pressure of the vapor due to temperature changes produced the same movement of the cup per degree and the calibration was not changed.

The operation of the device will now be described and first I will describe the operation of the device when it is adjusted to obtain defrosting cycles of the evaporator. The handle or control member |46 is rotated a small amount to move contact 96 to the right in Fig. 1 to the position shown in Fig. 6 with reference to line |80. With the

electrodes

44 and 96 out of contact the refrigerator warms up and bellows 22 expands to move head 56 to the right in Fig. 6 until the head strikes the stationary member 32 and its further,

movement is stopped by this member. As the refrigerator warms up, there is further expansion of the bellows 22 until about 32 F. is reached and if there is any frostpor ice on the evaporator, the temperature will not rise above 32 F.

The bulb on the tube I0 is mounted on the exterior and lower part of the evaporator so that as long as there is any ice or frost on the evaporator or cooler the temperature of the bulb will not rise above about 32 F. but as soon as the frost or ice is removed and the temperature of the box rises about 32 F. there will be further movement and expansion of the bellows 22. During the further expansion movement of the bellows and with the head 56 held stationary by the member 32, the bellows moves the rod 14 which is connected to the piston 12 within the tube 68 against the action of small spring 16, and this movement continues until the top of the piston 12 touches the abutment 54 and then moves the contact 44 against contact 96 to close the circuit. This position is shown in Fig. 6.

'I'he cooler will not start to cool immediately and consequently there will be continued expansion of the bellows and movement of contact M due to the thermal lag in the refrigerator' and contact 96 will be pushed to the right a small amount. 'I'he spring |26 behind contact 96 will take up this movement after the contacts Il and 96 have been brought together. In this way the electrodes or contacts come into firm contact and are held in this way while the circuit is complete. After the motor has been started and cooling of the refrigerator is started,.the liquid or fluid within the bellows will contract and condense and the bellows 22A will be moved toward the left. During the first part of this movement, piston 12 and rod 14 will be moved relatively to the tube 58 by expansion of spring 16 until the piston strikes the shoulder 'l0 on the tube 5l. During all this time the head 56 will still be held against the member 32 by main spring I0. After this movement the

parts

10, 12 and 1l again function as a unit and further contraction of the bellows will move the head 56 to the left and this movement will continue until the ring 62 strikes the abutment 54 and moves the contact 44 away from the contact 96 to open the circuit. In the defrosting range the temperature range is from about 16 F. to 36 F. This twenty degree range is obtained by combining the distance or slack between ring 62 and shoulder 60 on head 56 and the distance between the end of piston 12 and shoulder 6U. (Compare Figs. 4 and 6.)

With the control member set for defrosting, the refrigerating system continues to fluctuate from a temperature above the freezing point of Water to about 16 so that an average temperature is obtained which is suitable for household refrigeration. While this operation continues there is substantially no ice or frost collected on the evaporator or cooling member and also the humidity within the refrigerator is higher than with the refrigerators now in operation. During operation on these defrosting cycles due to the large temperature range, better ventilation of the air in the refrigerator is obtained because of the expansion and contraction of the air in the refrigerator.

The operation of the device will now be described when defrosting is not desired and when the system is working on a ten degree range below the freezing point of water or 32 F. This ten degree range is provided by the slack or distance between shoulder 60 and ring 62 on head 56. With the refrigerator Warm and with the bulb positioned at the bottom and exterior of the evaporator or cooler, the fluid within the bulb and tube I0 and within the bellows 22 will become warm and evaporate and expand to move the shell 26 away from the bottom portion ofA the housing. This expansion moves shoulder 60 on the member 58 to the rightin Fig. l and the shoulder 60 traverses the slack or distance between shoulder 66 and abutment 54 and then moves against the abutment 5I on one end of the contact M and moves the contact further to the right in Fig. 1 and makes contact with the other contact 96 as shown in Fig. 4. When the two contacts are brought together, the motor in the circuit is started and the refrigeration or cooling of the refrigerator is started. However, it takes a little time before the cooler in the refrigerator will start to cool and consequently there will be continued expansion of the bellows and movement of the contact M due to the thermal lag Within the refrigerator and contact 96 will be pushed to the right a small amount. The spring |26 positioned behind the contact 96 is provided to take up this amount of movement of the contact 96 after the

contacts

44 and 96 have been brought together. In this way the electrodes or contacts come into firm contact and are held in this way while the circuit is complete.

During this expanding movement the fluid within the bellows has worked against the action of the main spring 40 which is so chosen that for each unit of movement of the bellows there is a corresponding unit change in the temperature in the refrigerator.

As the refrigerator cooler starts to cool oli' and the temperature falls, the fluid within the tube lll and within the bellows 22 begins to contract 44 through abutment 54 into contact with elec.

trode 96, shoulder 60 does not separate the contacts. A further contraction of the bellows moves the head 56 along further until the ring 62 on head 56 strikes the other side of theabutment 54 and then the contact 44 is pulled away from the electrode or contact 96 and the circuit is broken, the position of the parts being shown in Fig. 5. During this time the head 56 has a steady and positive movement toward the left so that the contact will be positively moved away from contact 96. At this end of the operation there will be further cooling of the refrigerator due to the fact that the operationv is not suddenly stopped even though the motor is shut ofi' and therefore there will be further contraction of the bellows and consequent movement of the contact 44 away from the contact 96 so as to get a positive and even breaking and sullicient separation oi the contacts. During this operation (not defrosting) it will be seen thatfthe parts 1li, 12, 56 and 58 have functioned as a unit and have been held in this position by the small spring it.

As vshown in Fig. l, the thermostatic unit is set for about the range of 16 F. to slightly under 26 F. If lower temperatures are desired so that the range extends from about 6 F. to 16 F., for example, the control handle |46 is moved which rotates the screw member |09 within the head H5 to move the contact 96 to the left in Fig. l whereby the bellows will have to expand to a less extent to move contact 44 a shorter distance before ii; touches contact 96 on the iirst portion of the new cycle. But when the contacts are separated by the bellows and associated parts, a ten degree range is established which will be maintained until manually changed. In this way a lower temperature is obtained within the refrigerator. While the system is operating on this ten degree range the parts function in substantially the same manner as above given when no defrosting' is desired.

The top surface of piston 12 is normally below the shoulder 60 as shown in Fig. l, an amount such that it requires about ten degrees additional temperature to bring the end of the piston 12 to the level'of shoulder 60. Should it be desirable to have .the defrosting cyclefrom about 16 F. yto 33 F., the piston 12 can be made longer so that the end of the piston normally will be closer to and abut'the head 54 sooner and about an extra seven degrees rather than another ten degrees as above given will be added to the ten dcgree range between shoulder 60 and ring 62 on head 56.

This case is filed as a continuation and improvement of the device disclosed and claimed in my copending application.

What I claim is:

l. A device of the character described, including, in combination, a housing, a pair iii.'A contacts therein, means for moving one of said contacts including an expansible and contractiblebellows` responsive -to temperature changes, said means also including 'an elongated member having a vhead for abuttinga'stationary-part of said/housing for stopping movement of said member after said bellows has expanded a certain amount and a piston member adapted to be moved relatively to said elongated member to move one of said contacts toward said other contact upon further expansion of said bellows after said headvis held by said stationary part of said housing. Y

2; A device of the character described, including, in combination, a housing, a pair of contacts therein, meansfor moving one of" said contacts including an expansible and contractible bellows responsive to temperature changes, said means also including an elongated member having a head for abutting a stationary part of said housing for stopping movement of said member after said bellows has expanded acertain amount and a piston member adapted to be moved relatively to said elongated member to move one of said contacts toward said other contact upon further expansion of saidsbellows after said head is held by said stationary part of said housing, said elongated member upon contraction of said bellows being released and being provided with means for said member having a head for abutting a stationary part of said housing for stopping movement of said member after said bellows has expanded a certain amount, said means further including a piston member adapted to move one of said contacts toward said other Contact upon `further expansion of said bellows after said head is stopped by said stationary part of said housing.

4. A device of the character described, including, in combination, a housing, a pair of contacts therein, means for moving one of said contacts including a thermostatic element, a spring associated with said thermostatic element for obtaining Aa certain amount of movement of said thermostatic element per degree change of temperature in said thermostatic element, said means including a member provided with an abutment for moving one of said contacts away from the other contact when said thermostatic element is cooling off, said member having a head for abutting a stationary part of said housing for 4stopping movement of said member when said thermostatic element is Warnung up, said means further including a piston member adapted to move one of said contacts toward the other contact upon further warming up of said thermostatic element after said head is stopped by said stationary part.

5. A device of the character described, including in combination, a housing, a movable electrode and a stationary electrode therein, means for moving said movable electrodeincludlng a charged expansible and contractible bellows responsive to temperature changes, said means also including a member having an abutment and a head, said head being adapted to abut a stationtrode toward said other electrode upon further expansion of Isaid bellows after said head is stopped by said stationary part on said housing.

6. A device of the character described, including in combination, a housing, a movable electrode and a stationary electrode therein, means for moving said movable electrode including a charged expansible and contractible bellows responsive to temperature changes, said means also including a member having an abutment and a head, said head being adapted to abut a stationary part of said housing for stopping movement of said member after said bellows has expanded a certain amount, said means further including a piston member movable relatively to said rst mentioned member to move said movable electrode toward said other electrode upon further expansion of said bellows after said head is stopped by said stationary part on said housing and said hollow member having an abutment for moving said movable electrode in the opposite direction to separate said electrodes upon sufcient contraction of said bellows.

7. A device of the character described for controlling the range of temperatures in refrigerators which includes a housing, a movable electrode and a stationary electrode therein, means for moving said movable electrode toward and away from said other electrode to make and break contact in response to temperatures in the refrigerator, said means including a charged bellows, telescoping members connecting said bellows and movable electrode, resilient means holding said member in position, and adjustable means movable with respect to said casing and other than said stationary electrode engageable by one of said telescoping members to limit the extent of movement thereof.

8. A device of the character described, including, in combination, a housing, a movable electrode and a stationary electrode, a charged bellows associated with said housing and responsive to changes in temperature, means for transmitting movements of said bellows to said movable electrode, `said means including a member provided with an abutment for moving said movable electrode away from said other electrode when said bellows is contracting, said member having a head for abutting a stationary part of saidv housing for stopping movement of said member after said bellows has expanded a certain amount, said means further including a pis- 'ton member adapted to move said movable elec-- trode toward said other electrode upon further expansion of said bellows after said head is stopped by said stationary part.

9. A device of the character described, including in combination, a housing, a movable electrode and a stationary electrode, a charged bellows associated with said housing and responsive to changes' in temperature, means for transmitting movements of said bellows to said movable electrode, said means including a member provided with an abutment for moving said movable electrode away from said other electrode when.

said bellows is contracting, said member having a head for abutting a stationary part of said housing for stopping 'movement of said member after said bellows has expanded a certain amount, said means further including a piston member adapted to move said movable electrode toward said other electrode upon further expansion of said bellows after said head is stopped by Said stationary part, said stationary part including an adjustable cup member whereby the calibration of said device may be changed.,

l0. A device of the character described, including, in combination, a housing, a movable electrode and a Vstationary electrode therein, means for adjusting the position of said stationary electrode, a charged bellows associated with said housing and responsive to changes in temperature, means for transmitting movements of said bellows to said movable electrode, said means including a hollow member having a flange and a piston member having a shoulder and a spring for normally holding said flange against said shoulder, said bellows upon expansion moving said hollow member and said piston member as a unit until said hollow member strikes a stationary part of said housing, said piston member then operating' against the action of said spring upon continued expansion of said bellows for moving said movable electrode toward said other electrode.

11. A device of the character described, including in combination, a housing, a movable electrode and a stationary electrode therein, means for moving said movable electrode including an expansible and contractible member responsive'to temperature changes, said means also including relatively movable members for actuating said movable electrode, one of said members being held after a certain amount of movement and said other member being further moved to move said movable electrode toward and intocontact with said other electrode.

12. A device of the character described, including in combination, a housing, a movable electrode .and a stationary electrode therein, means for moving said movable electrode including an expansible and contractible member responsive to temperature changes, said means also including relatively movable members for actuating said movable electrode, one of said members being held after a certain amount of movement and said other member being further moved to move said movable electrode toward and into contact with said other electrode, said held member upon contraction of said expansible and contractible member being released and being adapted to separate said electrodes.

i3. A device of the character described, including in combination, a housing, a pair of contacts in said housing and arranged coaxially,I means for moving one of said contacts, said means including a charged bellows member responsive to temperature changes in a space to be refrigerated, the charge for said bellows consisting of a gas near its condensation point, a collar adjustably mounted in said housing and a spring between said collar and said bellows member applying the same pressure to said bellows member independent of the adjustment of said collar for maintaining a certain movement of said bellows member per degree change of temperature in said bellows member, said spring being so mount--v ed with respect to said collar and bellows as to retain its same relative elongation independently of a change in adjustment of said collar,

14. A device of the character described, including in combination, a housing, a pair of coaxially arranged contacts therein, an expansible and contractible bellows in said housing, a cup within said bellows, a stationary member in said housing, a spring between said cup and said member for obtaining a certain amount of movement of said bellows per degree change of temperature in said bellows, means mounted in said cup and including a, member provided with an abutment for moving one of said contacts away from the other contact when said bellows is contracting, said last mentioned member having a head for abutting said stationary member for stopping movement of said movable member after said bellows has expanded a certain amount, said means further including a piston member adapted to move one of said contacts toward the other contact upon further expansion of said bellows after said head is stopped by said stationary member.

15. A device of the character described, including in combination, a housing, a pair of contacts therein, an expansible and contractible bellows in said housing, a cup within said bellows, a stationary ring in said housing, a spring between said cup and said ring for obtaining a certain amount of movement of said bellows per degree change of temperature in said bellows, means mounted in said cup and including a member provided with an abutment for moving one of said contacts away from the other contact when said bellows is contracting, said member having a head for abutting said stationary ring for stopping movement of said member after said bellows has expanded a certain amount, said means further including a piston member adapted to move one of said contacts toward the other contact .upon further expansion of said bellows after said head is stopped by said stationary ring, said ring being threadedly engaged with said housing whereby the position of said ring may be changed for adjustment purposes.

16. A device of the character described, including, in combination, a housing, a pair of coaxially arranged contacts therein, one of said contacts being movable, a bellows in said housing and responsive to changes in temperature in a confined space, means for transmitting movements of said bellows to said movable contact, said means including a hollow member having a ange and a piston member having a shoulder and a spring for normally holding said iiange against said shoulder, said bellows upon expansion moving said hollow member and said piston member as a unit until the hollow member strikes a stationary part of said housing, said piston member then operating against the action of said spring upon continued expansion of said bellows for moving the movable contact against the other contact. and said hollow member having an abutment for moving the movable contact in the opposite direction upon sufficient contraction of said bellows and after said hollow member and piston member again act as a unit.

17. A device of the character described including in combination a housing, aswitching element within said housing comprising amovable and stationary electrode, means for moving said movable electrode including an expansible andcontractible member responsive to temperature changes, said means also including relatively movable members for actuating said movable electrode, one of said members being held after a certain amount of movement and said other member being further moved to move said movable electrode toward and into contact with said other electrode, and means connected to said switching element to move the same bodily with relation to said temperature responsive member to set the control temperatures of the device.

13. A device of the character described including in combination a housing, a switch element therein comprising a pair of contacts, means including a thermostatic element for moving one of said contacts, said means also including a member having a head for abutting a stationary part of said housing for stopping movement of said member after said thermostatic element has expanded a certain amount and a piston member adapted to be moved relatively to said member to move one of said contacts toward said other contact upon further expansion of said thermostatic element after said head is held by said stationary part of said housing, and regulating means for moving said switching element bodily with relation to'said thermostatic element to set the control temperatures of said device.

19. A device of the character described, including, in combination, a housing, a pair of contacts therein, means including a thermostatic element for moving one of said contacts, said means also including a member having a head for abutting a stationary part of said housing for stopping 4movement of said member after said thermostatic element has expanded a certain amount and a piston member adapted to be moved relatively to said member to move one of said contacts toward said other contact upon further expansion of said thermostatic element after said head is held by said stationary part of-said housing.

EDWIN G. GAYNOR.

CERTIFICATE OF CORRECTION.-

Patent No. 2,lTY,h.80.

October 2li,

EDWIN c.l cArNoR.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, first column, operated; same page, second column,

line 51+, for the words operated and operable" readoperating and line 11,8, for belows read bellows;

page li, first column, line )49, for "about" read above; and that the said Letters -Patent should be read with this correction therein that the same may conform to the record of the-case in the Patent Office.

signed erlesenen this 19th dey er December, A.` D. 1959.

(Seal) Henry Van Arsdale Acting Commissioner of Patents.