US2523788A - Carbon pile temperature device - Google Patents

Description

Sept 26, 1950 n P. P. sTocKlNGER E 2,523,788

CARBON PILE TEMPERATURE DEVICE Filed Aug. 2o. 1947 INVEN TOR. R41/L l? .Smc/mese AT TOE/VE Y Patented Sept. 26, 1950 UNITED STATES PATENT OFFICEv j CARBON PILE TEMPERATURE DEVICE Paul P. Stockinger, South Bend, Ind., assignor to Bendix AvationCorporation, South Bend, Ind., a corporation of Delaware Application August 20, 1947, Serial No. 769.1721

l 6 Claims.

This invention relatesto a carbon pile temperature sensing device and more particularly to improved means for applying the pressure on the carbon pile.

The carbon pile herein shown includes a plurality of carbon discs arranged in series so that the compressive force acting in an axial direction on the pile varies the resistance therethrough.

An object of the invention resides in the provision of a carbon pile the resistance of which is varied by novel spring means.

An important object of the invention lies in the provision of a temperature sensitive carbon pile the resistance of which varies a given amount over a preselected temperature range.

A still more important object of the invention lies in the provision of a temperature sensitive carbon pile having an adjustment for preselecting the temperature range in which the resistance of the pile can be made to vary.

eferring now to the single gure embodying my improved temperature sensitive carbon pile, reference numeral in designates a housing provided with a mounting flange l2 for securing the carbon pile into position. A steel tubular element or cartridge i4 is fixed at one end to the mounting l2 and depends therefrom. The end of the tubular element whichis joined to the flange is open to receive a quartz rod I6 one end of which bottoms on the closed end I1 of the tubular element I4. The other end of the quartz rod extends into the housing In and is equipped with a slotted cap i8 to engageone end of a member the other end of which engages a slotted pin 22. The length of the quartz rodi-s relatively unaffected by temperature changes while on 'the other hand the tubular element, on the bottom ot which the quartz rod rests, changes its length in accordance with temperature variations. A stem 24 is slidably positioned` in a stepped hub 2B which is integral with a housing 28. The hub threaded exteriorly at 30 andpasses through a threaded opening 32 in the housing lil. A nut .8f3 can threaded onto the huby to thereby lock the housing 23 in place. A plurality of stacked carbon discs 38 are disposed within a porcelain sleeve 38 into which oneend f stem 2.4 extends for contact with the innermost carbon disc. This` endof the stem 24 carries a conducting disc edly engages lever 10.

40 which` is in Contact with one of the carbon discs 3E. A similar metal disc 42 is located in the end of thevporcelain sleeve opposite disc 40-and is held. in place by a screw 44 threadedly engaging themetaldisc and passing through a support G mounted on the porcelain sleeve and spaced therefrom by spacers 48 through which screws 59 pass to thereby threadedly engage the endt of the porcelain sleeve. 38. Afwire 52` is held in conducting relationship'to the metal disc 42 by a nut 54 threadedly engaging the screw 44. The innermost carbon` disc is grounded through disc 4t andstem 24 to housing I0. A coiled spring 58 circumscribesfthe stem 24 so that one end of the spring abuts the hub 26 and the other end., or free end. of the springis in engagement with awasher carried by the stem. The washer is heldfrornl axial'movementto the left by a pin' 62 which passes throughthe stem. rThis actionof spring' 58 urges the stem to the left, thereby tending to separate the carbon discs and consequently increase the resistance ofl the carbon pile. The spring 58 is comparatively light, being only of suflicient strength to urge the stem to. the left so that the disc 40 tends to ride against the bottom of the housing 28. Spring E4 is arranged to apply pressure to the end of the stemv 24 through member 20, whereby compression of the carbon discs 36 may be obtained.

The preselected temperature range through which the carbon pile acts may be varied by changing the position of member 20 relative tothe end of the pin 24. Adjusting screw 815 is bored at 68 to receive the pin 22 against which one end ofmember 20v abuts. Pin 22Vts freely-in the bore 68 to permit adjustment of screw E6 whichthread- Turning screw 66 in or out ofthe lever will change thetemperature range throughwhlchthe carbon discs act to vary theresistance thereof. That is, turning screw 56 changes the position of member 2D relative to the end of stem` 24. The lever 'l0 is pivoted at-one endy in bracket l2 which is carried by the housing l0. The other end or free end of the lever is connected to an armature T4 controlled in its movement by a solenoid 16 mounted on abracket 18 secured to housing I8 by screws 8U. Housing l!)r is bored at 82 to permit the adjusting screw 66 to slide freely therein. The lever 10 is urged against a stopy 84 by a spring 86 when the sole'- noid is deenergized. In the present position oi the lever the solenoid is deenergized so that member 2G is warped only slightly at its center thereby holding the member toward the stem 24. Energization of the solenoid I5 warps the member away from the end of the stem, Hence to bring the member back to its original position where it will be in contact with stem 24 the temperature ambient probe I4 must be increased so that the probe I4 will expand to allow the quartz rod i6 to drop down thereby permitting member 20 to straighten out. With this arrangement the temperature range within which the carbon discs are compressed may be changed manually or automatically.

Operation of the device is as follows:

With the parts in the position shown in the drawing the stem is in its extreme left position and out of contact with member 2B. At this time the carbon discs 36 are loosely arranged in the porcelain sleeve 38 so that the ohmic resistance of the discs is maximum, or some otherwise preselected value. If we now assume an increase in the temperature ambient the probe I4, there will be an increase in the length of the probe and a consequent moving downward of the quartz rod I5. This action permits member 20 to straighten out thereby contacting the end of stem 24. When in this position of Contact relationship with stem 24 spring B4 acts in an axial direction along the stem to compress the carbon discs to decrease the ohmic resistance thereof. The springr 64 is aided by the force built up in member 2!! when warped or bowed.

In the position shown, the probe I4 must be subjected to a predetermined ambient before compression of the discs takes place. The device may be adjusted so that the ambient temperature required to compress the discs is either more or less than that for which it is presently set. This adjustment made by changing the posi- 4tion of screw SG either manually or automatically. If for example. it should be desired to not compress the carbon discs until a higher ambient temperature was attained adjusting screw would be turned into the lever 'I8 thereby moving the center of member 2li farther away from stem 24, which means that probe I4. must get longer than before to allow the quartz rod to drop down where the member 2 again contacts the stem. Besides the manual adjustment as aforementioned the temperature range may be automatically varied by energization of solenoid 16. For example, if the solenoid were energized, armature 'I4 would be pulled inwardly thereby pulling lever 'IG downwardly to cause member 2?) to warp farther away from the end of stem 24. This means that the temperature ambient the probe will have to be increased over that previously required to position the members so that the spring could compress the carbon discs.

Although this invention has been described in connection with certain specific embodiments, the principles are susceptible of numerous other applications that will readily occur to persons skilled in the art.

Having thus described the various features of the invention, what I claim as new and desire to secure by Letters Patent is:

1. In combination with a carbon pile the ohmic resistance of which is caused to be varied in accordance with preselected temperatures, temperature sensing means, means for applying a compressive force to the carbonA pile, means responsive to said first named means and interposed between said second named means and said carbon pile for controlling the compressive force, said last named means including a flexible member having one end operatively connected to said rst named means and flexed to form a bow with its curved portion acting on said second named means in a direction tending to relieve the carbon pile of the compressive force, and means for adjusting the preload on said member, whereby the ohmic resistance of the carbon pile can be preselected to correspond to a given temperature.

2. In combination with a carbon pile the ohmic resistance of which is varied in accordance with preselected temperatures, means for sensing temperature, means for applying a compressive force to the carbon pile, a member having one end supported by said first named means and means supporting the other end of said member and manually adjustable for preloading said member axially to thereby cause it to deflect laterally, said member being operatively connected to said carbon pile and to said second named means in a manner such that the compressive force of said second named means acting on said carbon pile varies with the deflection of said member.

3. In combination with a carbon pile the ohmic resistance of which is varied in accordance with preselected temperatures, means for sensing temperature including an expansible tubular element in which a non-expansible rod is carried, means for applying a compressive force to the carbon pile, and a preloaded flexible member interposed between said last mentioned means and said carbon pile, said member having an end supported by said non-expansible rod with the preload applied thereby in a direction opposing the compressive force acting on the carbon pile and yieldable in the opposite direction in response to temperatures within a predetermined temperature range for varying the preload.

4. In combination with a carbon pile the ohmic resistance of which is varied in accordance with preselected temperatures, means for sensing temperature including an expansible, tubular element in which a non-expansible rod is carried, a spring for applying a compressive force to the carbon pile, a member interposed between said spring and carbon pile, said member being so constructed and arranged that it is normally exed by said non-expansible rod in a direction opposing the compressive force acting on the carbon pile but yieldable in the opposite direction in response to temperatures within a predetermined temperature range, whereby control of the compressive force of the spring obtained, and adjusting means for changing the extent of flexing of said member.

5. In combination with a carbon pile the ohmic resistance of which is caused to be varied in accordance with preselected temperatures, temperature sensing means, means for applying a compressive force to the carbon pile, and means responsive to said first named means and interposed between said second named means and said carbon pile for controlling the compressive force, said last named means including a leaf spring supported at its ends for engagement at its intermediate section with said second named means, said leaf spring normally preformed in a direction tending to resist the compressive force.

6. In combination with a carbon pile the ohmic resistance of which is caused to be varied in accordance with preselected temperatures, temperature sensing means, means for applying a compressive force to the carbon pile, means rem sponsive to said first named means and interposed between said second named means and said carbon pile for controlling the compressive force, said last named means including a leaf spring supported at its ends for engagement at its intermediate section with said second named means, said leaf spring normally preformed in a direction tending to resist the compressive force, and adjustable means at one of the ends of the leaf spring for varying the preformation thereof.

PAUL P. STOCKINGER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 865,304 Harrison Sept. 3, 1907 1,291,598 Moskowitz Jan. 14, 1919 1,678,843 Arnold July 31, 1928 1,788,678 Knaak Jan. 13, 1931 1,820,060 Fitzgerald Aug. 25, 1931 1,884,232 Rehm Oct. 25, 1932 2,060,316 Hoesel Nov. 10, 1936 2,403,534 Kehse July 9, 1946

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