US2479392A - Automatic choke control - Google Patents

Description

Aug. 16, 1949. w, MILLER 2,479,392

AUTOMATI C CHOKE CONTROL Filed March 16, 1946 j .ZVVEN TOR) Mum/ l L/ MLLER) y \Q L M 4m ETORNE 1x Patented Aug. 16, 1949 UNITED STATES PATENT OFFICE AUTOMATIC CHOKE CONTROL William W. Miller, Evansville, Ind. V

Application March 16, 1946, Serial No. 654,981 r 1 Claim.

This invention relates to remote manual control of automatic chokes in engine fuel induction systems. In many instances, the well-known automatic choke mechanism, particularly in extremely cold weather, will over choke to produce a flooded condition causing extreme difficulty in getting the engine started. My invention is intended to be applied to the well-known automatic choke mechanism now being commercially applied immediately ahead of the carburetor on engines employed in automobiles and the like, and it is the primary object of my invention to provide at some conveniently accessible place such as upon the instrument panel of the automobile an adjustable lever or knob, preferably with an indicating device, whereby the knob may be adjusted in accordance with weather temperature conditions to permit the choke mechanism to operate in accordance with the weather temperature and thus avoid the tendency to flood particularly in extremely cold weather. The invention of course may be employed for adjusting the choke mechanism to meet prevailing temperatures of different climates without further manipulation when conditions so warrant, although it is believed that the device constituting the invention should be made readily available as above indicated to prevent change in adjustment from season to season to secure a much better starting performance.

A further primary object of the invention is to provide a device that may be readily and quickly applied to existing choke mechanisms with a minimum amount of change and of labor in installation. A further primary object of the invention is to provide a device of the nature described which will permit "hand choking of the engine when desired independently of the choking mechanism itself, particularly at milder temperatures.

These and many other objects and advantages of the invention will become apparent to those versed in the art in the following description of the one particular form of the invention as now best known to me, as illustrated in the accompanying drawing, in which,

Fig. 1 is a view in side elevation and partial section of a structure embodying the invention;

Fig. 2, a view in vertical section on a line 2-2 in Fig. 1;

Fig. 3, a vertical section on a line 33 in Fig. 2; and,

Fig. 4, a top plan view.

Like characters of reference indicate like parts throughout the several views in the drawing.

The choke mechanism herein shown and de- 2. scribed is one of the commercially used types mounted directly over a down-draft carburetor, between it and the air cleaner. The part. of the choke mounted between these two'units (not shown) consists essentially of a thimble I0 within which is mounted a butterfly valve II on a shaft I2 carried transversely across through the thimble ill to one side of the center thereof to have the valve I I normally biased by the influence of gravity toward an open position, a partially open position being indicated in Figs. 3 and 4 in the drawing. This shaft I2 extends beyond the outside of the thimble III and terminates by a short length within a cupped head l3 mounted at one side of thethimble Ill by-=means of the bracket I4. I

Fixed on the outer'end of the shaft I2 within the head I3 is an arm I5 from which extends a horizontally disposed finger I6 outwardly from the head I3. A finger I'I extends circumferentially about the shaft I2 in spaced relation therefrom as an integral part of the arm I5. The outer free end of the finger I1 is pivotly connected' to a linkI8 in turn pivoted to a plunger I9 freely slidable within the vertically disposed cylinder 20. The lower end of the cylinder 20 is connected with the intake of the engine, preferably through the carburetor, all in the usual and well-known manner, Thus the travel of the plunger I9 is downward, as viewed in Fig. 2, when the engine is operating and producing the vacuum in the carburetor, thereby pulling the butterfly I I to its open position.

A cupped cover 2| is provided to enclose the head I3. A shaft 22 is carried axially through the cap 2| to be revoluble in relation thereto. In the form herein shown, the shaft 22 is supported by the cap by means of inner and outer washers 23 and 24 respectively slidingly engaging corresponding faces of the cap 2|, these washers 23 and 24 being fixed to the shaft 22.

The shaft 22 extends into the cap 2I a sufficient distance to permit the inner end 25 of the helically coiled thermostat element 26 to be fixed thereto such as having the end carried through a slot in the end of the shaft 22. The outer end of the element 26 is carried outwardly substantially radially of the coil by an end portion 21 to be in the path of the finger I6 whereby unwinding of the element 26, Fig. 2, will shift the finger It in a counter-clockwise direction to produce corresponding rotation of the shaft I2. Accordingly suflicient unwinding of the element 26 will cause the valve II to be carried to the closed position.

manner..- Thiszpartial vacuumiwithinethatecavity will tend tioipul l ini'air. through therentrance open: ing 3|] which is normally connected to a portion of the engine subjected to heat immediately the engine is set into operation.

The shaft 22 has connected therewitlig' F'i gt-l an extension shaft 3| herein shown-lasrbeing,.,a flexible shaft to permit its being carried to any suitable position to one side ofntliesli'aftffi:with-- out having to employ universal joints oricranks and the like. The shaft 3| is preferably enclosed within a housing 32 and is carried to some point where an adjusting knob 33 'fixed to" the end of theshaft 3| may-be rocked to" causecorresponding rotation of the-shaft; 22v Preferably" a needle 34 is fixed to the-knob33 toi travel over an indicating segment 35 to indicate different positions of adjustment of tli'e sh-aft 22, Y and correspondingly different positionsof the'tliermosta't; element end 21. Thatisk'by turning tli'e-knob331'the thermostatelement 2E5 is'bodily shifted circumferentially within-the cap'2kt'o variably position its end 21'; variably -position-in g thisend- 21-' of course determines'when that endwvill strike the finger I 6 at f a predeter-minedwlow temperature and I thus cause the valve 4 I to' close and ."tl'iereby induce the carburetor to" supply anrenriched fuelamixture to the engine. It is this variable positioning feature thairconstitutes:tlrewgist'tof; the invention whereby. "the degree of valve: I Ir. time :of closure is determined; 1 The. element *2 65 itself serves. as a resilient-spring member againstv which :the fin'e ger: 16 yieldinglyttravel a :limited distance under the vacuum applicationair theuplunger I9 tending to pull the finger l6- against thethermo stab element *endril! Of :course if the: end- 21' has-sheen shifted-toa ter in?- a counter-clockwise direction by reason-.- (if-the lowering of" the; tems perature; then: a greater-degree of: resistance:.-is set upsto travel of.-the.;fi 1l er1|6:itoqpelmit the valve H' to reach-a sufficiently openposition so as to. preventifovenfloodingli of'ther engine;

Whilel have herein shown and described my invention in the one form as now best known to me, it is obvious that structural changes may be employed particularly in the type of thermostatic element employed, its mounting, and the interconnection between it and the adjusting means, all without departing from the spirit of the invention, and I therefore do not desire to be limited to that precise form beyond the limitationswh-ichmay be imposed 'by :the following claim. 7

I claim: 7

A remote choke valve control comprising the combination with a choke valve shaft, a vacuum cylinder-,a rigid arm fixed directly to said shaft, a plungermzthe cylinder connected to said arm for rotating the shaft upon production of vacuum in said cylindere'of a housing fixed in respect to said shaft; a helically coiled spring member about said' shaft within said housing; a spring mounting post extending axially of said shaft, freely through said housing'to extend therefrom; the inner end of-saidspring member being fixed to said post; a finger 'on said arm engaging the outer free end of said spring member whereby said spring member is tended to be Wound upon said production of vacuum; said spring member being thermal-responsive to unwind and wind about said post upon varying degrees-of heat applied thereto; a flexible shaft fixed axially-0f and-to -said post to extend to a remote control position; a member at said position fixed onthe flexible shaft as meansforrotating it; a washer fixed to said post on the inside and-outsiderespectively of said housing to' hold said post against longitudinal travel-upon rotation thereof.

REFERENCES CITED The; following references are of recordinthe me of' this. patent:

UN ITED' STATES PATENTS- Number Name Date 2,124,504" Brown July 19,1938 2,127,735 Hunt Aug. 23,1938 2,139,355 Coffey Dec. 6,11938 2,143,153" Hunt Jan. 10, 1939 2,155,233 Mantz' Apr. 18, 1939 2,302,197 Edwards Nov. 17,1942 2,346,016 Ericson Apr. 4, 1944

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