US2190671A - Automobile heating system - Google Patents

Description

1940- H. J. DE N. M COLLUM 2,190,571

AUTOMOBILE HEATING SYSTEM Filed April 6, 1938 2 Sheets-Sheet 1 0 1a a! 99 h w Feb 1940- H. J. DE N. MCCOLLUM 2,190,671

AUTOMOBILE HEATING SYSTEM Filed April 6, 1938 2 Sheets-Sheet 2 E llllll l i l l lk HIHIFTIIIHTTIHIIIIHHI IIIIIIIIIHIII III 2 7 I INTAKE MAN/FOLD 12006202014 fizzryJDeZ/MZallum 6M7 LQCQMI/M 546 Patented Feb. 20, 1940 UNITED STATES PATENT OFFICE ,6 Claims.

My invention relates generally to unit type heaters, and more particularly to improved control mechanisms for automobile heaters of the internal combustion type. It is an object of my invention to providean improved control switch and operating means therefor in which a thermostatic element is utilized as a switch member and as a means for actuating the control switch.

It is a further object of my invention to provide an improved form of control mechanism for heaters employing forced air circulation, in which the means for forcing the circulation of the air r being heated is controlled automatically and independently of the main control device of the heater.

Other objects will appear from the following description, reference being had to the accompanying drawings, in which:

Figs. 1, 2, and 4 are sectional views of a heater control switch, showing the parts in different positions;

'Fig. 3 is a front elevational view of the control switch, other portions of the heater being shown in section;

Fig. 5 is a plan view of the heater control switch; and

Fig. 6 is a diagrammatic view of the elements of the heater and the electrical circuits associated therewith.

The improved control mechanism disclosed and claimed in this application is adapted to be used in conjunction with heaters of the type disclosed in my copending applications, Serial No. 61,213, filed January 28, 1936, and Serial No. 120,523, filed January 14, 1937. The important parts of the heaters disclosed in the aforesaid applications are diagrammatically illustrated in Fig. 6, wherein a casting i0 is provided with a combustion chamber l2 to which a-mixture of fuel and air is supplied through a carbureting device 14. The latter is connected to a suitable source of liquid fuel by a conduit l6, the source usually being the float bowl of the carburetor used to supply the 45 internal combustion engine, when the heater is used on an automobile, although any other suitable source of liquid fuel may be utilized. The mixture of fuel and air in the combustion chamber l2 is ignited by means of an igniter shown as a high resistance element l8, which may be of nichrome or similar wire and is electrically heated to a temperature sufiicient to cause ignition of the mixture in the combustion chamber l2.

The products of combustion flow through passageways formed in a reigniter plug 26 into a circuitous passageway 22 formed in a radiator casting 24, the passageway terminating at the inlet end of a vacuum compensating nozzle 26 which is connected by a conduit 28 to the intake manifold 30 of the automobile engine. In the event that the heater is used for heating enclosures other than an automobile, the passageway 22 may be connected with a suitable source of suction, as might be provided by a suction fan or blower. The radiator casting 24 is surrounded by a cup-shaped shell 32 which has heat radiating fins 34 secured therearound. It will be understood that the radiator will generally be located in the passenger compartment of an automobile and that air from the compartment will be circulated downwardly past the radiator by means of a fan 36 driven by an electric motor 38.

' The operation of the heater is controlled by means of a handle button 40 which is secured at the outer end of a valve stem 42, the inner end of which carries a valve 44 cooperable with the mouth of the nozzle 26, the latter forming a seat for the valve.

As best shown in Fig. 1, the stem 42 is guided in a bushing 46 which is threaded in the combustion chamber casting 24 and is provided with a suitable slot to receive a spring detent 48 engageable with one of three annular grooves 50; 52,

54, turned in the stem 42'. As shown in Fig. 1, the detent is in engagement with the groove 50, thus holding the valve 44 in its position in which it is shown in Fig. 6. This is the normal position when the heater is not in operation. When the heater is in full operation, the detent spring 48 engages the groove 54 as shown in Fig. 2, while when the heater is operating for low volume of heated air delivery, the stem 42 will be pushed inwardly so that the spring detent 48 engages the annular groove 52. A switch supporting plate 56 is se- ,cured closely adjacent and in heat conducting contact with the end of the shell 32 by means of the bushing 46, the plate 56 being held from rotary movement. about the bushing 46 by a projection 58 struck from the end wall of the shell 32 and engaging in an aperture 66 formed in the plate. to conduct heat from the shell 32 and will thus be maintained at substantially the same temperture as the shell.

A rigid switch arm 62, a flexible switch arm 64, anda bimetal thermostatic switch arm 66 are secured to the supporting plate 56 by a pair of rivets 68, each of these switch arms being insulated from the other and from the plate 56 by sheets of insulation 1!], l2, l4, l6, and tubular insulators i6 and 80 surrounding the rivets. A metallic spacer 8| lies adjacent the clamped portion of the bimetal switch element 66, and a metallic end plate 82 forms a means for distributing the clamping pressure of the rivets. The insulating strip 1 is preferably of thin mica and extends sufficiently beyond the spacer 8| and the adjacent surface of the supporting plate 56 to make certain that the thermostatic bimetal switch arm 66 will not at any time come into The plate 56 is thus adapted readilycontact with the'plate 56. This strip 16 is very thin and thus conducts heat to the arm 66 without a great drop in temperature.

Contact points in the form of rivets are secured to the ends of switch arms, there being a contact point 84 for the rigid switch arm 62, a contact 86 secured to the end of the bimetal switch arm 66, and a pair of contacts 88 and 96 carried by and in electrical connection with the flexible switch arm 64. The contact point 96, which is cooperable with the contact point 86, is carried by a bent strip 92, which is clamped to the extremity of the switch arm 64 by means of a clip 94. The contact rivet 88 is carried by a bent metallic strip 96 which is likewise secured to the oifset end of the contact arm 64. A strip 98 of insulating ma terial is secured adjacent the extremity of the offset portion of the switch arm 64. An insulating strip I66 is secured to the inner surface of the resilient switch arm 64 by means of a rivet I62 so as to prevent electrical contact of the latter with the bimetal switch arm 66. A sheet of mica I66 is secured to thesupporting plate 56 by rivets I66, and thus prevents electrical contact between the contact 96 or its carrying arm 92 and the switch plate 56.

The flexible switch arm 64 has a terminal I68 which is connected by a conductor II6 with a suitable source of electrical energy, such as a battery II 2 (Fig. 6) representative of the storage battery of an automobile when the heater is'installed upon an automobile. The current from the battery to the conductor III! may be controlled by a switch I I4 which may be the ignition switch or a separate switch, preferably operated incidental to the operation of the ignition switch of the automobile. The rigid switch arm 62 has a terminal I I6 which is connected by a conductor IIB with the igniter I6, the circuit through the latter being completed through the casting I6, which is shown as grounded. The bimetal switch arm 66 has a terminal I26 (Fig. 3) which is connected by a conductor I22 with the motor 38, the other terminal of the motor being grounded to complete. the return circuit to the battery.

In operation the switch parts will normally be in the position shown in Fig. 1 when the heater is cold and the control knob 46 is in "off position. In this position the control knob 46 abuts against the extension of arm 64 and holds the contacts 64, 86 separated, and holds the contact 96 away from the contact 86. Thus, neither the igniter nor the fan is supplied with current.

When it is desired to initiate operation of the heater, the control button 46 is pulled outwardly from the position which is shown in Fig. 1, to the position shown in Fig. 2, whereupon the switch arm 66, due to its inherent resiliency, will swing to the left (Fig. 2) to complete the circuit through the contacts 68 and 84. With the heater cold the bi-metal contact strip 66 will, however, be unflexed, and contact will not be established between the contact points 86 and 96.

After the heater has commenced operation and become heated to a temperature sufiicient to warrant the operation of the fan motor to circulate air from the passenger compartment of the vehicle past the radiator, the bi-metallic thermostatic contact strip 66 will flex sufliciently to close the motor circuit by pressing the contact 86 against the contact 96. Current will thus be supplied to the motor 38 while it is still being supplied to the igniter through the circuit completed by the contacts 84 and 88. After a short period,

however, the iii-metallic th rm t tic switc arm 66 will exert more and more pressure against the contact 96 as the radiator is raised to a higher temperature, and as soon as the radiator attains contact rivet .96 will be pressed against the insulating strip I64 and thus further flexure of the switch arms will be prevented.

If, when the switch parts are in the position shown in Fig. 4, the control button 46 is moved to the position in which it is shown in dotted lines in Fig. 4, to shut off the heater, such movement of the control button will not have any effect upon the switch parts, but will merely close the valve 64 thus causing extinguishment of the flame in the combustion chamber of the heater. Thereafter the fan motor 38 will continue to 0perate and the radiator will be cooled, delivering its heat to the air in the passenger compartment of the vehicle, until the bi-metallic switch arm 66 cools sufi'iciently to permit the extension of the resilient switch arm 66 to abut against the control button 46. Shortly thereafter, upon continued clockwise flexure of the bi-metallic switch arm 66, the contacts 66 will be moved from the contact 96 and the parts will resume their normal inoperative position, as shown in Fig. l.

It will be noted that in the switch construction herein disclosed, the bi-metallic thermostatic switch arm 66, when heated, flexes counterclockwise, in the same direction that it would otherwise be moved by the control button in shutting off the heater. In fact, under normal conditions, the bi-metallic switch arm 66 is not subjected to any externally applied forces at any portion of its cycle of operation. As a result, since the bi-metallic switch arm is'subjected only to the strains incidental to changing temperature, it will maintain its adjustment throughout the life of the heater and will operate effectively to close and open the switch contacts at exactly the desired temperatures.

Due to the arrangement of theswitch contacts. the fan motor will continue to operate after the heater has been shut off, thus efficiently delivering to the air in the passenger compartment of the vehicle the residual heat of the radiator after the heater has been shut off.

Due to the simple arrangement of the switch contacts and the bi-metallic thermostatic element for operating the same, the initial adjustment of the thermostatic element for causing it to open and close the switch contacts at the desired temperatures may be readily made,

merely by bending the thermostatic element slightly. After this initial adjustment has been made, there will be no occasion for further adjustment due to the fact previously mentioned,

that the bi-metallic thermostatic switch arm 66 is not subjected to strainsfrom external forces.

While I have shown and described a particular embodiment of my invention, it will be readily apparent to those skilled in the art that numerous variations may be made in the construction disclosed without departing from the basic principles thereof. I therefore desire to include in the following claims'all such modifications and variations as will be readily apparent to those skilled in the art, and by which substantially the results of my invention may be attained in substantially the same way.

I claim:

1. In an automobile heater of the internalcombustion type, the combination of a combustion chamber, electrical ignition means assooiated with said chamber for igniting a combustible mixture of liquid fuel and air therein, a radiator receiving the products of combustion from said chamber, means for withdrawing said products of combustion from said radiator under reduced pressure, a manually operable valve for controlling the flow of the products of combustion through said radiator, an electric motor, a fan driven thereby for circulating air past said radiator, and a switch mechanism for controlling the supply of electrical energy to said fan motor and to said igniter, said switch mechanism comprising a rigid contact arm, a resilient contact arm normally held from engagement with said rigid contact arm by said manually operable control element and completing an elec' trical circuit to said igniter when said control element is moved to position to cause operation of the heater, a bimetallic thermostatic switch arm cooperable with said resilient switch arm to complete an electrical circuit for supplying power to said fan motor and operable when said radiator attains a predetermined temperature to move said resilient switch arm from contact with said rigid switch arm and thereby open the circuit to said electrical igniter.

2. In an automobile heater of the internal combustion type, the combination of a combustion chamber, electrical igniting means associated with said chamber, a radiator heated by the products of combustion, means to promote a flow of fuel and air through said combustion chamber and radiator below atmospheric pressure, means for circulating air past said radiator to be heated thereby, said means including an electric motor, a manually operable control element for controlling the flow of the products of combustion through said radiator, two pairs of switch' contacts, one pair being in series with said electrical igniter and the other pair being in series with said electric motor, a flexible conductor supporting two of said four contacts, temperature responsive means supporting another of said contacts and a rigid support for the fourth contact, and means operated by said manual control element to close the pair of switch contacts in series with said igniter, said temperature responsive means receiving heat from said radiator operable sequentially to close said electric motor contacts and shortly thereafter to separate said igniter contacts as the temperature of said radiator passes through a predetermined range of temperature change.

3. In a switch mechanism for heaters of the internal combustion type employing a combustion chamber, a manually operable element to control the flow of fuel to said combustion chamber, electrical ignition means, a radiator, an electric motor driven ,means for circulating air past said radiator, comprising: a relatively rigid support in a heat conducting relationship with said radiator, a relatively rigid contact arm, a resilient flexible contact arm', and a bimetal temperature responsive contact arm secured to said supporting plate and each arm insulated from the others and from said plate, means operable by said manually operable element to permit said resilient arm to engage said relatively rigid arm to complete a circuit to said igniter, and means operated by said bimetal arm to complete a circuit to said electric motor when said radiator attains a predetermined temperature and thereafter to swing said flexible arm away from said relatively rigid arm, thereby to open the electrical circuit to said igniter.

4. A switch assembly comprising a support, a relatively rigid contact arm secured to said support, a flexible arm and a temperature responsive arm secured to said support between the latter and said relatively rigid arm, said arms being insulated from each other and from said support, a pair of contact points carried by said flexible arm and facing in the same direction, contact points respectively on said rigid arm and temperature responsive arm engageable respectively with the contacts on said flexible arm, manually operable means to condition said flexible arm for flexure toward said relatively rigid arm to close the electrical circuit through the contact points thereof, said temperature responsive arm being adapted upon being heated to complete a circuit with said flexible arm and upon continued rise in temperature to move said flexible arm in a direction to open the circuit between said flexible arm and said relatively rigid arm.

5. In a temperature responsive switch assembly, the combination of a relatively rigid contact point, a flexible arm carrying a contact cooperablewith said relatively fixed contact, a temperature responsive element adapted upon an increase in the temperature thereof to engage said flexible arm and make electrical contact therewith and operable upon a further increase in temperature thereof to separate the contact on said flexible arm from its associated contact on said rigid arm, and a manual control to flex said flexible arm to such a position that it cannot contact said rigid arm, but can contact said temperature responsive arm when the last said arm is at a high temperature.

6. In a switch device, the combination of a manual control element movable into at least two positions, a support, a relatively rigid contact arm, a resilient contact arm, and a bimetallic contact arm, all of said arms supported by said support and electrically insulated therefrom and from each other, a contact point on said rigid arm, a second .contact point on said resilient arm and facing the first said contact point, said second contact point adapted to touch the first said contact point when said resilient arm is free, a third contact on said bimetallic arm and a fourth contact supported by said resilient arm, said manual control when in one position adapted to engage and flex the resilient arm away from the rigid arm and in a second position to be removed from contact with the resilient arm and allow the first and second of said contacts to close, said bimetallic arm when heated adapted to close the third and fourth of said contacts and upon further heating to flex the resilient arm away from the rigid arm and open said first and second contacts while maintaining the third

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