US3624578A

US3624578A - Three function thermal-electrical switch

Info

Publication number: US3624578A
Application number: US91681A
Authority: US
Inventors: Alan F Stocker; Lynn S Brock; Raymond E Graf
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1970-11-23
Filing date: 1970-11-23
Publication date: 1971-11-30
Anticipated expiration: 1988-11-30

Abstract

A switch that is responsive to both the temperature within an enclosure and the ambient temperature near the exterior of the enclosure. A wax-mixture-filled container at one end of the switch housing monitors the internal temperature of the enclosure and moves a contact assembly within the housing along a pair of terminals in response to the monitored temperature. A bimetal member in the contact assembly effects an electrical connection between the terminals in response to the ambient temperature as sensed within the switch. An insulating member precludes the electrical connection when the wax mixture is above a certain temperature. When the wax mixture is at an even higher temperature the contact assembly completes another current path between one of the terminals and a third terminal.

Description

United States Patent [72] Inventors Alan F. Stocker North Tonawanda; Lynn S. Brock, Williamsville; Raymond E. Gral, Youngstown, all of N.Y. [21] Appl. No. 91,681 [22] Filed Nov. 23, 1970 [45] Patented Nov. 30, 1971 [73] Assignee General Motors Corporation Detroit, Mich.

154] THREE FUNCTION THERMAL-ELECTRICAL SWITCH 7 Claims, 7 Drawing Figs. v

152] 0.8. CI 337/299, 73/3683, 337/124 [51] lnt.Cl ..ll0lb 37/52 [50] Field 01 Search 73/3683, 363.5; 337/299, 124, 382, 389, 398, 399,101; 234/34; 200/153 M [56] References Cited UNITED STATES PATENTS 2.265.586 12/1941 Vernet 73/368.3

52A fi an d? Primary Examiner-.1. V. Truhe Assistant Examiner-L. A. Schutzman Artorneys-.l. L. Carpenter and Paul Fitzpatrick ABSTRACT: A switch that is responsive to both the temperature within an enclosure and the ambient temperature near the exterior of the enclosure. A wax-mixture-filled container at one end of the switch housing monitors the internal temperature of the enclosure and moves a contact assembly within the housing along a pair of terminals in response to the monitored temperature. A bimetal member in the contact assembly effects an electrical connection between the terminals in response to the ambient temperature as sensed within the switch. An insulating member precludes the electrical connection when the wax mixture is above a certain temperature. When the wax mixture is at an even higher temperature the contact assembly completes another current path between one of the terminals and a third terminal.

THREE FUNCTION THERMAL-ELECTRICAL SWITCH This invention relates'to multiple function switches and, more particularly, to switches that are responsive both to the temperature within an enclosure and to the ambient temperature without the enclosure.

In the switch, or control device, field there are a multitude of designs, many of which have been devised to perform a given function to fulfill a certain need. In the present instance it has been observed that modern automobiles employing internal combustion engines operate best when their ignition is advanced or retarded in accordance with both the temperature of the engine, as measured by the engine coolant tem perature, and the ambient temperature adjacent the engine, as measured within the engine compartment of a vehicle. In addition, experience has suggested the need of indicating to a vehicle occupant when the temperature of the engine is excessive so as to preclude his operating the vehicle in a fashion which will damage the engine.

It is, therefore, an object of this invention to provide a switch which electrically connects a pair of terminals in response to both the temperature within an enclosure and also electrically connects a third terminal to one of the other terminals in response to the enclosure internal temperature.

' It is another object of this invention to provide a switch which employs a wax mixture to monitor the internal temperature of an enc re and a bimetal element to monitor the amdjacent the enclosure and which electri- M urality of terminals in response to the monitored tempera res.

It is yet another object of this invention to provide a switch which monitors the coolant temperature of an engine with a reservoir containing a heat expansible substance that undergoes substantial volumetric increases at certain tempera tures, the switch controlling a plurality of electrical connections in response to expansion of the substance.

The foregoing and other objects and advantages of the subject invention will become apparent from the accompanying description and drawings, in which:

FIGS. 1 through 3 are schematic diagrams illustrating various operational conditions of a switch embodying the principles of the subject invention;

FIG. 4 is a perspective view of the switch in FIGS. 1 through FIG. shows a contact assembly employed in the switch of FIGS. 1 through 4;

FIG. 6 is a plan view of the contact assembly is FIG. and

FIG. 7 is an exploded view of the contact assembly in FIG. 5.

As shown in FIGS. 1 through 3, a switch 10 according to the principles of the subject invention may be employed to control the energization of a control network 12 and a lamp 14 by a battery 16 in accordance with the temperature within an enclosure 18 and the ambient temperature adjacent the enclosure 18. For example, the enclosure 18, a section of which is shown in FIGS. 1 through 3, may be the portion of a vehicle engine that is filled with engine coolant 20 and is commonly called a water jacket. In addition, the lamp 14 may be a HOT telltale of a well-known type employed to indicate that the coolant 20 is excessively hot, and that the control network 12 may be of a type designed to control the ignition timing of the engine l8.

As persons versed in the art will appreciate, the timing of a vehicles ignition greatly affects the operation of the vehicle. Many modern vehicles therefore employ apparatus for utilizing the intake manifold vacuum of an engine to advance the ignition supplied the engine by a distributor when the engine is operating under certain conditions, the application of the manifold vacuum to the distributor being controlled by an electrical solenoid. For purposes of this description, it sufiices to state that the network 12 controls the engine 18 in this fashion and that the ignition which is supplied the engine 18 by a suitable ignition system (not shown) may be advanced whenever the lead 22 that connects the switch 10 to the net work 12 is deenergized. Conversely, when the switch 10 electrically connects the lead 22 to the battery 16 the lead 22 is energized so as to preclude the network 12 from advancing the ignition supplied to the engine 18.

The switch 10 includes a housing 24 having a cover section 26 and an electrically grounded base section 28, a portion 30 of the base section 28 being threaded for insertion into a threaded hole in the engine 18. For convenience in manufacturing the housing 24, it may be desirable to crimp the base section 28 over the cover section 26, as shown in FIG. 4. A heat transferring reservoir 32 which contains a wax mixture 34 is secured to the base section 28 so as to extend into the coolant 20 for monitoring the coolant 20 temperature. By way of example, the reservoir 32 may b made of copper alloy which readily transmits heat so that the wax mixture 34 partakes of the temperature inside the engine 18.

As persons versed in the art will appreciate, many waxes are characterized as undergoing substantial volumetric expansion while melting. Typical of these waxes are beeswax and paraffin, either of which may be used in the wax mixture 34. Accordingly, each time the coolant 20 temperature exceeds the melting temperature of a wax in a wax mixture, the wax is melted and the volume of the wax mixture 34 is correspondingly increased, the waxes having higher melting temperatures remaining solidified in the wax mixture as waxes having lower melting temperatures are changed from the solid to the liquid state. While the switch 10 structure may be modified to accommodate several changes in the wax mixture 34 volume, the illustrated embodiment of the switch 10 is designed to accommodate two waxes in the wax mixture 34, one wax having a melting temperature of approximately 220 F. and the other wax having a melting temperature of approximately 252 F. The wax mixture 34 may also include a substance which increases the thermal conductivity of the wax mixture 34, to facilitate rapid melting of the waxes as each of their respective melting temperatures are reached by the engine coolant 20. Copper powder suspended in the wax mixture 34 has been found to be especially useful for this purpose.

A cover member 36 is provided for sealing the reservoir 32 so as to preclude the wax mixture 34 from escaping from the reservoir 32 into the central portion of the housing 24. In the illustrated embodiment, an outer lip 38 of the reservoir 32 is crimped over the cover member 36 so as to tightly enclose the reservoir 32. To allow for expansion of the wax mixture 34 as the waxes are melted, the cover member 36 contains an aperture in which is slidably positioned a plunger 40 that is dr'ivably coupled to a contact assembly 42. As will subsequently be explained, hydraulic pressure in the wax mixture 34 causes the plunger 40 to be hydraulically expelled from the reservoir 32 as each of the waxes in the wax mixture 34 is melted.

The contact assembly 42 includes a contact support member 44 which supports first and

second spring contacts

46 and 48 and a bimetal element 50, as shown in greater detail in FIGS. 5 through 7. The contact support member 44 is recessed, as shown at 45 to facilitate coupling the contact support member 44 to the plunger 40. Accordingly, as the plunger 40 is expelled from the reservoir 32, as shown in FIGS. 2 and 3, the contact assembly 42 is moved in its entirety away from the engine 18.

The switch 10 includes first and second terminals 52 and 54 which serve the dual purpose of accommodating external connections to the switch 10 and of guiding the contact assembly 42 as it is moved by the plunger 40. As shown in FIG. 1, the

contacts

46 and 48 are self-biased into slidable engagement with the terminals 52 and 54, which extend through

apertures

56 and 58 in the contact support member 44. The lower most ends 60 and 62 of the terminals 52 and 54 are bent at right angles so as to support the contact support member 44. A compressive spring 64 is provided for biasing the contact support member 44 against the plunger 40 so as to push the plunger 40 into the wax mixture 34 until either the contact support member 44 is supported by the ends 60 and 62 of the first and second terminals 52 and 54 or the hydraulic pressure in the reservoir 32 offsets the force applied to the plunger 40 by the spring 64.

As the'plunger 40 is expelled from the reservoir 32 by the lower melting temperature wax in the wax mixture 34 melting the first contact 46, which is rounded at its free end 65, is physically separated from the first terminal 53 by an insulating member 66 having a sloped end 67. When the higher melting temperature wax in the wax mixture 34 is melted, the extension of the plunger 40 the reservoir 32 is at a maximum and an electrical connection is effected from the second contact 48 to the lamp 14 through a third electrical terminal 68, which includes an adjustment screw 70, as will now be explained in conjunction with FIGS. 2 and 3.

When it is desired to operate the engine 18 in weather above 67 F. the bimetal member 50, which in the illustrated embodiment is in the form of a snap disc having a snapping temperature of approximately 67 F., is in the position illustrated in FIG. 5. When the snap disc 50 is in this position, the first contact 46 is biased into engagement with the second contact 48 by the snap disc 50 due to the warm ambient temperature.

Since the warm weather conditions would also place the engine l8 and the coolant at the same temperature as the snap disc 50, which temperature is assumed to be greater than the 67 F. but less than 220 F., both of the waxes in the wax mixture 34 are in a solid state. The plunger 40 extension from the reservoir 32 is then held at a minimum by the spring 64. Accordingly, under these conditions the lead 22 is energized by the battery 16 through the first and second terminals 52 and 54 and the

contacts

46 and 48, as previously mentioned. When the lead 22 is energized it may be assumed that the control network 12 precludes advancing the engine 18 ignition by means of the intake manifold vacuum.

However, when the temperature of the coolant 20 exceeds 220 F., the lower melting of the waxes in the wax mixture 34 is melted, causing the plunger 40 to be hydraulically expelled from the reservoir 32 to the partially expelled position illustrated in FIG. 2. Since the first contact 46 is electrically insulated from the first terminal 52 by the insulating member 66 when the plunger 40 is in the partially expelled position of FIG. 2, the lead 22 is deenergized and the control network 12 is allowed to advance the ignition timing of the engine 18. As persons versed in the art will appreciate, advancing the ignition of the engine 18 when the coolant 20 is hot allows the engine 18 to operate at a cooler temperature.

Should the temperature of the coolant 20 be increased past the melting temperature of the second wax, the plunger 40 is then hydraulically expelled from the reservoir 32 to its fully extended position illustrated in FIG. 3 so as to engage the screw 70 with the second contact 48. This completes a current path from the battery 16 through the second terminal 54, the second contact 48, the third terminal 68, and the lamp 14 so as to energize the lamp 114 and advise the vehicle operator of the overheated condition of the engine 18.

When the engine is started under cold ambient conditions that are below 68 F., both of the waxes in the wax mixture 34 are in a solid state and the snap disc 50 is in the position illustrated in FIG. 1. Since the contacts 46 and 88 are not closed by the snap disc 50 under these conditions, the lead 22 is initially deenergized when the engine 18 is started. Accordingly, the control network 12 is able to advance the ignition timing of the engine 18 to assure that the engine I8 is able to idle smoothly and provide the vehicle occupants with the level of performance which they desire. Under these cold conditions, the engine 18 is normally provided with a richer fuel mixture; i.e., one which contains an increased percentage of fuel, so that the advanced ignition time of the engine 18 provides the engine 18 with an increased opportunity to assure complete combustion of the fuel which it receives. Once the ambient temperature adjacent the engine 18 has been increased above 67 F. the snap disc 50 is changed to the position illustrated in FlG. 5 so as to close the

contacts

46 and 48 and energize the lead 22. When the lead 22 is energized, the control network 12 is precluded from further advancing of the engine 18 timmg.

When the engine 18 has warmed sufficiently so that the coolant 20 is above 220' F., the wax in the wax mixture 34 having the lower melting temperature is melted so as to partially expel the plunger 40 from the reservoir 32, causing the insulating member as to separate the first contact 46 from the first terminal 52. When the first contact 46 is separated from the first terminal 52, the lead 22 is no longer energized through the switch 10 and the control network 12 is again permitted to advance the ignition timing of the engine 18, causing it to run cooler. Thereafter, the operation of the switch It) continues as previously explained.

While the switch herein described has been discussed in conjunction with apparatus for controlling the timing of a vehicle enm'ne, persons versed in the art will appreciate that the switch may be used in a wide variety of other systems without departing from the spirit of this invention.

What is claimed is:

l. A multiple function switch that is responsive both to the temperature within an enclosure and the ambient temperature without the enclosure comprising, in combination, a housing; a heat transferring reservoir adapted for insertion into the enclosure and secured to the housing; fist means mechanically responsive to temperature positioned within the reservoir for monitoring the interior temperature of the enclosure through the reservoir, said means assuming a first condition when the enclosure interior temperature is below a certain temperature and a second condition when the enclosure interior temperature is above the certain temperature; at least first and second electrical terminals positioned within the housing and extending outside the housing for connection of external leads thereto; contact means for completing an electrical connection between the first and second terminals in accordance with the enclosure interior temperature and the ambient temperature, said contact means including a contact support member that is driveably coupled to said first means for movement therewith, at least first and second contacts secured to the contact support member, each contact being biased into sliding engagement with one of the terminals, and second means mechanically responsive to temperature secured to the contact support member for monitoring the ambient temperature within the housing and for effecting an electrical connection between the contacts in response to the ambient temperature, thereby electrically connecting the terminals in accordance with the ambient temperature; and means for electrically insulating the fist contact from the terminal it engages when said first means is in one of said conditions and permit the first contact to engage the terminal when said first means is in the other condition so as to effect an electrical connection between terminals in response to changes in the enclosure inten'or temperature.

2. A multiple function switch that is responsive to both the temperature within an enclosure and the ambient temperature outside the enclosure comprising, in combination, a housing; a heat transferring reservoir secured to the housing and adapted for insertion into the enclosure, the reservoir being enclosed except for an aperture which communicates with the interior of the housing; a wax mixture disposed in the reservoir so as to be responsive to the temperature within the enclosure, the waxes in the wax mixture each being characterized by considerable volumetric expansion while melting; a plunger slidably positioned in the aperture so as to extend into the wax mixture whereby expansion of the wax mixture partially expels from the plunger from the reservoir into the housing; a plurality of electrically isolated conductive terminals positioned os as to extend into the housing from outside the housing; and means for electrically connecting the terminals within the housing in response to the temperature within the enclosure and the ambient temperature as sensed within the housing, said means including a contact support member driveably coupled to the plunger for movement therewith in response to melting of the wax by the enclosure internal temperature, the

plunger moving the contact support member from a first position to a second position when the wax is changed between liquid and solid phases, at least first and second electrically isolated contacts mounted on the contact support member, each of the contacts being biased to slidably engage one of the terminals, one of the terminals being positioned for engagement by one of the contacts when the contact support member is in one of said positions, means for preventing said one contact from engaging said one terminal when the contact support member is in the other of said positions, thereby electrically connecting at least two of the terminals in response to the temperature inside the enclosure, and means mechanically responsive to temperature mounted on the contact support member for sensing the ambient temperature within the housing and for electrically connecting the contacts in response to the ambient temperature, thereby electrically connecting at least two of the terminals in response to the ambient temperature.

3. A switch that is responsive to both ambient temperature and the temperature within an enclosure comprising, in combination, a housing, a portion of the housing being adapted for insertion into the enclosure; a heat transmitting reservoir secured to said housing portion so as to extend externally of the housing efiective to partake of the enclosure interior temperature when said housing portion is inserted into the enclosure; means mechanically responsive to temperature positioned in the reservoir so as to partake of the enclosure interior temperature through the reservoir; a plunger driveably coupled to said means and positioned so as to protrude into both the reservoir and the interior of the housing, said means being characterized as having a first condition in which the extension of the plunger from the reservoir is at a minimum when said means is below a certain temperature, a second condition in which the plunger is partially expelled from the reservoir by said means when said means is above the certain temperature, and a third condition in which the expulsion of the plunger from the reservoir by said means is at a maximum when said means is above an elevated temperature that is higher than the certain temperature; a contact assembly including a contact support member driveably coupled to the plunger for movement therewith, first and second electrically isolated contacts supported by the contact support member, and second means mechanically responsive to temperature supported by the contact support member for effecting an electrical connection between the contacts in response to the ambient temperature as sensed by said second mechanically responsive means within the interior of the housing; at least first, second and third electrical terminals extending within the housing from without the housing, the first and second terminals each being positioned for engagement by one of the contacts as the plunger moves the contact assembly, thereby enabling the second mechanically responsive means to effect an electrical connection between the first and second terminals in response to ambient temperature; and the third terminal being positioned so that the second contact is moved into engagement therewith when the expulsion of the plunger from the container is at said maximum and the enclosure interior temperature is above the elevated temperature; insulating means positioned within the housing for separating the first contact from the terminal it engages when the extension of the plunger from the container has reached said partially expelled state indicative of the enclosure interior temperature being above the certain temperature, thereby preventing the first terminal from being in electrical contact with the second terminal when the enclosure interior temperature is above the certain temperature; and means for biasing the plunger into the reservoir when the plunger is not expelled from the reservoir by the first mentioned mechanically responsive means.

4. A switch that is responsive to both ambient temperature and the temperature within an enclosure comprising, in combination, a housing, a portion of the housing being adapted for insertion into the enclosure; a heat transmitting reservoir secured to said housing portion so as to extend externally of the housing effective to partake of the enclosure interior temperature when said housing portion is inserted into the enclosure a mixture of at least two heat expansible substances having different melting temperatures positioned in the reservoir so as to partake of the enclosure interior temperature through the reservoir; each substance in the mixture being characterized as undergoing substantial volumetric expansion while melting; means for enclosing the container for preventing the mixture from passing between the reservoir and the interior of the housing; a plunger positioned in said means effective to extend both into the housing and into the reservoir so as to be responsive to the volume of the mixture, the mixture hydraulically expelling the plunger from the reservoir as each substance is melted so that the extension of the plunger from the reservoir is an indication of the enclosure interior temperature; a contact assembly including a contact support member driveably coupled to the plunger for movement therewith, first and second electrically isolated contacts supported by the contact support member, and means mechanically responsive to the ambient temperature supported by the contact support member by effecting an electrical connection between the contacts in response to the ambient temperature; at least first, second and third electrical terminals secured to the housing so as to extend therethrough, the first and second terminals being positioned such that the first contact is in sliding engagement with the first terminal and the second contact is in sliding engagement with the second terminal so that the mechanically responsive means effects an electrical connection between the first and second terminals in response to the ambient temperature, the contacts being moved relative to the terminals when the plunger moves the contact assembly, the third terminal being positioned so that the second contact is moved into engagement therewith when both of the substances are melted by the enclosure interior temperature whereby the second contact electrically connects the second and third terminals when the enclosure interior temperature is sufficiently high to melt both of the substances; insulating means positioned within the housing so as to separate the first contact from the first terminal when the enclosure interior temperature has melted the lower melting temperature substances, thereby preventing the first terminal from being in electrical contact with the second tenninal when said substance is melted; and means for biasing the plunger into the reservoir as the substances are solidified.

5. A switch that is responsive to both ambient temperature and the temperatures within an enclosure comprising, in combination, a housing, a portion of the housing being adapted for insertion into the enclosure a heat transmitting reservoir secured to said housing portion so as to extend externally of the housing effective to partake of the enclosure interior temperature when said housing portion is inserted into the enclosure a mixture of two waxes having different melting temperature positioned in the reservoir so as to partake of the enclosure interior temperature through the reservoir, each wax in the wax mixture being characterized as undergoing substantial volumetric expansion while melting, a cover member positioned to prevent the waxes from passing between the reservoir and the interior of the housing, the cover member having an aperture which communicates between the interior of the housing and the interior of the container; a plunger slidably positioned in the aperture so as to extend into the reservoir and be responsive to the volume of the wax mixture, volumetric expansion of the wax mixture hydraulically expelling the plunger from the reservoir as each wax is melted such that the extension of the plunger from the reservoir is indicative of the interior temperature of the enclosure; a contact assembly including a contact support member driveably coupled to the plunger for movement therewith, first and second electrically isolated contacts supported by the contact support member, and means mechanically responsive to temperature supported by the contact support member for effecting an electrical connection between the contacts in response to the ambient temperature; at least first, second and third electrical terminals secured to the housing so as to extend therethrough, the first and second terminals being positioned so that the first contact is in sliding engagement with the first terminal and the second contact is in sliding engagement with the second terminal, the third terminal being positioned so that the second contact is moved into engagement therewith when both of the waxes are melted by the enclosure interior temperature whereby the second contact electrically connects the second and third terminals when the enclosure interior temperature is sufficiently high to melt both of the waxes; insulating means positioned within the housing so as to separate the first contact from the first terminal when the enclosure interior temperature has melted the lower melting temperature wax, thereby preventing the first tenninal from being in electrical contact with the second terminal when said wax is melted; and means for biasing the plunger into the reservoir as the waxes are solidified by a cooling of the enclosure interior temperature.

6. A switch that is responsive to both ambient temperature and the temperature within an enclosure comprising, in combination, a housing, a portion of the housing being adapted for insertion into the enclosure; a heat transmitting reservoir secured to said housing portion so as to extend externally of the housing effective to partake of the enclosure interior temperature when said housing portion is inserted into the enclosure; a wax mixture including at least two waxes having different melting temperatures and a substance characterized as having substantial thermal conductivity positioned in the reservoir so as to partake of the enclosure interior temperature through the reservoir, each wax in the wax mixture being characterized as undergoing substantial volumetric expansion while melting; a cover member positioned to prevent the waxes from passing between the reservoir and the interior of the housing, the cover member having an aperture which communicates between the interior of the housing and the interior of the reservoir; an elongated plunger slidably positioned in the aperture so as to extend into the reservoir and be responsive to the volume of the wax mixture, volumetric expansion of the wax mixture hydraulically expelling the plunger from the reservoir as each wax is melted such that the extension of the plunger from the reservoir is indicative of the interior temperature of the enclosure; a contact assembly including a contact support member which contains at least two apertures and which is driveably coupled to the plunger for movement therewith, first and second electrically isolated contacts supported by the contact support member, and means mechanically responsive to temperature supported by the contact support member for effecting an electrical connection between the contacts in response to the ambient temperature; first and second elongated electrical terminals secured to the housing so as to extend therethrough and be oriented substantially parallel with'the plunger, the first and second terminals each being positioned so as to extend through an aperture in the contact support member and to be in slidable engagement with one of the contacts and the contact support member such that the first contact is in sliding engagement with the first terminal and the second contact is in sliding engagement with the second terminal, movement of the plunger thereby moving the contacts and the contact support member relative to the terminals, the terminals thereby guiding the contact support member; insulating means positioned within the housing so as to separate the first contact from the first terminal when the enclosure interior temperature has melted the lower melting temperature wax so as to partially expel the plunger from the reservoir, thereby preventing the first terminal from being in electrical contact with the second terminal whensaid wax is melted; a third electrical tenninal secured to the housing and extending therethrough so as to be engaged by the second contact when both of the waxes are melted by the enclosure interior temperature and the expulsion of the plunger from the reservoir is at a maximum, the second contact thereby electrically connecting the second and third terminals when the enclosure interior temperature is'sufficiently high to melt both of the waxes; and means for biasing the plunger into the reservoir as the waxes are solidified.

7. A switch that is responsive to both ambient temperature and the temperature within an enclosure comprising, in combination, a housing, a portion of the housing being adapted for insertion into the enclosure; a heat transmitting reservoir secured to the housing so as to extend externally of the housing effective to partake of the enclosure interior temperature when said housing portion is inserted into the enclosure; a mixture of two waxes having different melting temperatures positioned in the reservoir so as to partake of the enclosure interior temperature through the reservoir, each wax in the wax mixture being characterized as undergoing substantial volumetric expansion while melting; a cover member positioned to prevent the waxes from passing between the reservoir and the interior of the housing, the cover member having an aperture which communicates between the interior of the housing and the interior of the reservoir; a plunger slidably positioned in the aperture so as to extend into the reservoir and be responsive to the volume of the wax mixture, volumetric expansion of the wax mixture hydraulically expelling the plunger from the reservoir as each wax is melted such that the extension of the plunger from the reservoir is dependent upon the interior temperature of the enclosure; a contact assembly including a contact support member driveably coupled to the plunger for movement therewith, first and second electrically isolated contacts supported by the contact support member, 'and means mechanically responsive to temperature supported by the contact support member for effecting an electrical connection between the contacts in response to the ambient temperature; at least first, second and third electrical terminals secured to the housing so as to extend therethrough, the first and second terminals being positioned so that the first contact is in sliding engagement with the first terminal and the second contact is in sliding engagement with the second terminal as the plunger moves the contact assembly, the third terminal being positioned so that the second contact is moved into engagement therewith when both of the waxes are melted by the enclosure interior temperature whereby the second contact electrically connects the second and third terminals when the enclosure interior temperature is sufiiciently high to melt both of the waxes; insulating means positioned within the housing so as to separate the first contact from the first terminal when the enclosure interior temperature has melted the lower melting temperature wax, thereby preventing the first terminal from being in electrical contact with the second terminal when said wax is melted; and means for biasing the plunger into the reservoir as the waxes are solidified.

g ga UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent: No. 3,624,578 Dated November 30, 1971 Alan F. Stocker, ln e w ls) Lynn 5. Brock and Raymond E. Graf It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 44, after "Fig. insert 5 Column 2, line 13, "b" should read be line 22, "a" (second occurrence) should read the Column 3, line 6, "53" should read 52 line 9, after "40 insert from line 28, "then" should read thus line 57, "68 should read 67 Column 4, line 17, after "be" insert modified considerably from the embodiment herein described and may be ----7 line 25, "fist" should read first line 48, "fist" should read first line 67, delete "from"; line 68, os" should read so Column 6, line 22, "by" should read for Signed and sealed this 26th day of September 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOT'ISCHALK Attesting Officer Commissioner of Patents

Claims

1. A multiple function switch that is responsive both to the temperature within an enclosure and the ambient temperature without the enclosure comprising, in combination, a housing; a heat transferring reservoir adapted for insertion into the enclosure and secured to the housing; fist means mechanically responsive to temperature positioned within the reservoir for monitoring the interior temperature of the enclosure through the reservoir, said means assuming a first condition when the enclosure interior temperature is below a certain temperature and a second condition when the enclosure interior temperature is above the certain temperature; at least first and second electrical terminals positioned wiThin the housing and extending outside the housing for connection of external leads thereto; contact means for completing an electrical connection between the first and second terminals in accordance with the enclosure interior temperature and the ambient temperature, said contact means including a contact support member that is driveably coupled to said first means for movement therewith, at least first and second contacts secured to the contact support member, each contact being biased into sliding engagement with one of the terminals, and second means mechanically responsive to temperature secured to the contact support member for monitoring the ambient temperature within the housing and for effecting an electrical connection between the contacts in response to the ambient temperature, thereby electrically connecting the terminals in accordance with the ambient temperature; and means for electrically insulating the fist contact from the terminal it engages when said first means is in one of said conditions and permit the first contact to engage the terminal when said first means is in the other condition so as to effect an electrical connection between terminals in response to changes in the enclosure interior temperature.

2. A multiple function switch that is responsive to both the temperature within an enclosure and the ambient temperature outside the enclosure comprising, in combination, a housing; a heat transferring reservoir secured to the housing and adapted for insertion into the enclosure, the reservoir being enclosed except for an aperture which communicates with the interior of the housing; a wax mixture disposed in the reservoir so as to be responsive to the temperature within the enclosure, the waxes in the wax mixture each being characterized by considerable volumetric expansion while melting; a plunger slidably positioned in the aperture so as to extend into the wax mixture whereby expansion of the wax mixture partially expels from the plunger from the reservoir into the housing; a plurality of electrically isolated conductive terminals positioned os as to extend into the housing from outside the housing; and means for electrically connecting the terminals within the housing in response to the temperature within the enclosure and the ambient temperature as sensed within the housing, said means including a contact support member driveably coupled to the plunger for movement therewith in response to melting of the wax by the enclosure internal temperature, the plunger moving the contact support member from a first position to a second position when the wax is changed between liquid and solid phases, at least first and second electrically isolated contacts mounted on the contact support member, each of the contacts being biased to slidably engage one of the terminals, one of the terminals being positioned for engagement by one of the contacts when the contact support member is in one of said positions, means for preventing said one contact from engaging said one terminal when the contact support member is in the other of said positions, thereby electrically connecting at least two of the terminals in response to the temperature inside the enclosure, and means mechanically responsive to temperature mounted on the contact support member for sensing the ambient temperature within the housing and for electrically connecting the contacts in response to the ambient temperature, thereby electrically connecting at least two of the terminals in response to the ambient temperature.

3. A switch that is responsive to both ambient temperature and the temperature within an enclosure comprising, in combination, a housing, a portion of the housing being adapted for insertion into the enclosure; a heat transmitting reservoir secured to said housing portion so as to extend externally of the housing effective to partake of the enclosure interior temperature when said housing portion is inserted into the enclosure; means mechanically responsive to temperature positioned in the resErvoir so as to partake of the enclosure interior temperature through the reservoir; a plunger driveably coupled to said means and positioned so as to protrude into both the reservoir and the interior of the housing, said means being characterized as having a first condition in which the extension of the plunger from the reservoir is at a minimum when said means is below a certain temperature, a second condition in which the plunger is partially expelled from the reservoir by said means when said means is above the certain temperature, and a third condition in which the expulsion of the plunger from the reservoir by said means is at a maximum when said means is above an elevated temperature that is higher than the certain temperature; a contact assembly including a contact support member driveably coupled to the plunger for movement therewith, first and second electrically isolated contacts supported by the contact support member, and second means mechanically responsive to temperature supported by the contact support member for effecting an electrical connection between the contacts in response to the ambient temperature as sensed by said second mechanically responsive means within the interior of the housing; at least first, second and third electrical terminals extending within the housing from without the housing, the first and second terminals each being positioned for engagement by one of the contacts as the plunger moves the contact assembly, thereby enabling the second mechanically responsive means to effect an electrical connection between the first and second terminals in response to ambient temperature; and the third terminal being positioned so that the second contact is moved into engagement therewith when the expulsion of the plunger from the container is at said maximum and the enclosure interior temperature is above the elevated temperature; insulating means positioned within the housing for separating the first contact from the terminal it engages when the extension of the plunger from the container has reached said partially expelled state indicative of the enclosure interior temperature being above the certain temperature, thereby preventing the first terminal from being in electrical contact with the second terminal when the enclosure interior temperature is above the certain temperature; and means for biasing the plunger into the reservoir when the plunger is not expelled from the reservoir by the first mentioned mechanically responsive means.

4. A switch that is responsive to both ambient temperature and the temperature within an enclosure comprising, in combination, a housing, a portion of the housing being adapted for insertion into the enclosure; a heat transmitting reservoir secured to said housing portion so as to extend externally of the housing effective to partake of the enclosure interior temperature when said housing portion is inserted into the enclosure a mixture of at least two heat expansible substances having different melting temperatures positioned in the reservoir so as to partake of the enclosure interior temperature through the reservoir; each substance in the mixture being characterized as undergoing substantial volumetric expansion while melting; means for enclosing the container for preventing the mixture from passing between the reservoir and the interior of the housing; a plunger positioned in said means effective to extend both into the housing and into the reservoir so as to be responsive to the volume of the mixture, the mixture hydraulically expelling the plunger from the reservoir as each substance is melted so that the extension of the plunger from the reservoir is an indication of the enclosure interior temperature; a contact assembly including a contact support member driveably coupled to the plunger for movement therewith, first and second electrically isolated contacts supported by the contact support member, and means mechanically responsive to the ambient temperature supported by the contact support member by effecting aN electrical connection between the contacts in response to the ambient temperature; at least first, second and third electrical terminals secured to the housing so as to extend therethrough, the first and second terminals being positioned such that the first contact is in sliding engagement with the first terminal and the second contact is in sliding engagement with the second terminal so that the mechanically responsive means effects an electrical connection between the first and second terminals in response to the ambient temperature, the contacts being moved relative to the terminals when the plunger moves the contact assembly, the third terminal being positioned so that the second contact is moved into engagement therewith when both of the substances are melted by the enclosure interior temperature whereby the second contact electrically connects the second and third terminals when the enclosure interior temperature is sufficiently high to melt both of the substances; insulating means positioned within the housing so as to separate the first contact from the first terminal when the enclosure interior temperature has melted the lower melting temperature substances, thereby preventing the first terminal from being in electrical contact with the second terminal when said substance is melted; and means for biasing the plunger into the reservoir as the substances are solidified.

5. A switch that is responsive to both ambient temperature and the temperatures within an enclosure comprising, in combination, a housing, a portion of the housing being adapted for insertion into the enclosure a heat transmitting reservoir secured to said housing portion so as to extend externally of the housing effective to partake of the enclosure interior temperature when said housing portion is inserted into the enclosure a mixture of two waxes having different melting temperature positioned in the reservoir so as to partake of the enclosure interior temperature through the reservoir, each wax in the wax mixture being characterized as undergoing substantial volumetric expansion while melting, a cover member positioned to prevent the waxes from passing between the reservoir and the interior of the housing, the cover member having an aperture which communicates between the interior of the housing and the interior of the container; a plunger slidably positioned in the aperture so as to extend into the reservoir and be responsive to the volume of the wax mixture, volumetric expansion of the wax mixture hydraulically expelling the plunger from the reservoir as each wax is melted such that the extension of the plunger from the reservoir is indicative of the interior temperature of the enclosure; a contact assembly including a contact support member driveably coupled to the plunger for movement therewith, first and second electrically isolated contacts supported by the contact support member, and means mechanically responsive to temperature supported by the contact support member for effecting an electrical connection between the contacts in response to the ambient temperature; at least first, second and third electrical terminals secured to the housing so as to extend therethrough, the first and second terminals being positioned so that the first contact is in sliding engagement with the first terminal and the second contact is in sliding engagement with the second terminal, the third terminal being positioned so that the second contact is moved into engagement therewith when both of the waxes are melted by the enclosure interior temperature whereby the second contact electrically connects the second and third terminals when the enclosure interior temperature is sufficiently high to melt both of the waxes; insulating means positioned within the housing so as to separate the first contact from the first terminal when the enclosure interior temperature has melted the lower melting temperature wax, thereby preventing the first terminal from being in electrical contact with the second terminal when said wax Is melted; and means for biasing the plunger into the reservoir as the waxes are solidified by a cooling of the enclosure interior temperature.

6. A switch that is responsive to both ambient temperature and the temperature within an enclosure comprising, in combination, a housing, a portion of the housing being adapted for insertion into the enclosure; a heat transmitting reservoir secured to said housing portion so as to extend externally of the housing effective to partake of the enclosure interior temperature when said housing portion is inserted into the enclosure; a wax mixture including at least two waxes having different melting temperatures and a substance characterized as having substantial thermal conductivity positioned in the reservoir so as to partake of the enclosure interior temperature through the reservoir, each wax in the wax mixture being characterized as undergoing substantial volumetric expansion while melting; a cover member positioned to prevent the waxes from passing between the reservoir and the interior of the housing, the cover member having an aperture which communicates between the interior of the housing and the interior of the reservoir; an elongated plunger slidably positioned in the aperture so as to extend into the reservoir and be responsive to the volume of the wax mixture, volumetric expansion of the wax mixture hydraulically expelling the plunger from the reservoir as each wax is melted such that the extension of the plunger from the reservoir is indicative of the interior temperature of the enclosure; a contact assembly including a contact support member which contains at least two apertures and which is driveably coupled to the plunger for movement therewith, first and second electrically isolated contacts supported by the contact support member, and means mechanically responsive to temperature supported by the contact support member for effecting an electrical connection between the contacts in response to the ambient temperature; first and second elongated electrical terminals secured to the housing so as to extend therethrough and be oriented substantially parallel with the plunger, the first and second terminals each being positioned so as to extend through an aperture in the contact support member and to be in slidable engagement with one of the contacts and the contact support member such that the first contact is in sliding engagement with the first terminal and the second contact is in sliding engagement with the second terminal, movement of the plunger thereby moving the contacts and the contact support member relative to the terminals, the terminals thereby guiding the contact support member; insulating means positioned within the housing so as to separate the first contact from the first terminal when the enclosure interior temperature has melted the lower melting temperature wax so as to partially expel the plunger from the reservoir, thereby preventing the first terminal from being in electrical contact with the second terminal when said wax is melted; a third electrical terminal secured to the housing and extending therethrough so as to be engaged by the second contact when both of the waxes are melted by the enclosure interior temperature and the expulsion of the plunger from the reservoir is at a maximum, the second contact thereby electrically connecting the second and third terminals when the enclosure interior temperature is sufficiently high to melt both of the waxes; and means for biasing the plunger into the reservoir as the waxes are solidified.

7. A switch that is responsive to both ambient temperature and the temperature within an enclosure comprising, in combination, a housing, a portion of the housing being adapted for insertion into the enclosure; a heat transmitting reservoir secured to the housing so as to extend externally of the housing effective to partake of the enclosure interior temperature when said housing portion is inserted into the enclosure; a mixture of two waxes having different melting temperAtures positioned in the reservoir so as to partake of the enclosure interior temperature through the reservoir, each wax in the wax mixture being characterized as undergoing substantial volumetric expansion while melting; a cover member positioned to prevent the waxes from passing between the reservoir and the interior of the housing, the cover member having an aperture which communicates between the interior of the housing and the interior of the reservoir; a plunger slidably positioned in the aperture so as to extend into the reservoir and be responsive to the volume of the wax mixture, volumetric expansion of the wax mixture hydraulically expelling the plunger from the reservoir as each wax is melted such that the extension of the plunger from the reservoir is dependent upon the interior temperature of the enclosure; a contact assembly including a contact support member driveably coupled to the plunger for movement therewith, first and second electrically isolated contacts supported by the contact support member, and means mechanically responsive to temperature supported by the contact support member for effecting an electrical connection between the contacts in response to the ambient temperature; at least first, second and third electrical terminals secured to the housing so as to extend therethrough, the first and second terminals being positioned so that the first contact is in sliding engagement with the first terminal and the second contact is in sliding engagement with the second terminal as the plunger moves the contact assembly, the third terminal being positioned so that the second contact is moved into engagement therewith when both of the waxes are melted by the enclosure interior temperature whereby the second contact electrically connects the second and third terminals when the enclosure interior temperature is sufficiently high to melt both of the waxes; insulating means positioned within the housing so as to separate the first contact from the first terminal when the enclosure interior temperature has melted the lower melting temperature wax, thereby preventing the first terminal from being in electrical contact with the second terminal when said wax is melted; and means for biasing the plunger into the reservoir as the waxes are solidified.