US2302527A

US2302527A - Carburetor structure

Info

Publication number: US2302527A
Application number: US347415A
Authority: US
Inventors: Irven E Coffey
Original assignee: Carter Carburetor Corp
Current assignee: Carter Carburetor Corp
Priority date: 1940-07-25
Filing date: 1940-07-25
Publication date: 1942-11-17
Anticipated expiration: 1959-11-17
Also published as: GB647957A

Description

Nov. 17, 1942. 1. E. COFFEY 2,302,527

CARBURETOR STRUCTURE Filed July 25, 1940 FIG.1.

INVENTOR IRVEN E. COFFE Y FIG.4."

ATTORNEY Patented Nov. .17, 1942 cAaBURE'roa STRUCTURE Irven E. Coffey, Normandy, Mo., asslgnor to Carter Carburetor CorporatiomSt. Louis, Mo., V a corporation of Delaware' I Application July 25, 1940, Serial No. 347,415'

' 7 Claims. (Cl. 261 -39) This invention. relatesto carburetors for internal combustion engines and consists partic-- ularly in novel means incorporated in an automatic choke carburetor for indicating to .the

operator the point in the throttle opening movement when the usual throttle operated unloader mechanism is about to become effective to open the choke valve.

During cold starting of an automobile engine,

thechoke valve is normally closed and the throttle valve partly open. In case the engine should become loaded due to the drawing of excessive gasoline into the cylinders, it is neces-.- sary to open the choke valve-and turn over the engine a few times in order that this excessive fuel may be swept out of the cylinders. This unloading is usually aifected through a connection to the throttle valve which positively opens the choke valve when the throttle is substantially fully opened.

There has been a tendency to provide for enare attained substantially by'the structure illustrated in the accompanying drawing in which:

Fig. 1 is an elevation of .an automobile carburetor showing the invention applied thereto,

parts being sectioned for clearer illustration.

Fig, 2 is an elevational view showing certain parts of the structure in Fig. 1, but with the choke valve closed.

Fig. 3 is a view similar to Fig. 2 but showing the choke valve closed and thethrottle valve partly opened to its starting position, and

Fig. 4 is a view similar to Figs. 2 and 3 but showing the throttle valve fully opened and the choke valve in its unloaded position.

ergizin the usual engine selft-starter motor by partial movement of the throttle pedal. insteadof through the intermediary of a separate pedal or button. Where such unloader" and starting functions are controlled by the throttle pedal, the driver may inadvertently'depress the pedal far enough during cranking, to force the choke valve open, wherefor it may be impossible 'to get of the throttle valve.

Another object is to provide means for rendering such additional indicating resistance ineile'ctive upon still further opening movement of the throttle so that the driver need not, oppose such resistance while cranking the engine with the choke in the unloading" position.' v

Still another object is to provide means for freeing the choke valve from the indicating mechanism when the throttle has been moved to its proper starting position so as to facilitate pulsations or breathing of the choke valve,

during cranking.

The carburetor shown in Fig. 1 includes a barrel l forming a downdraft mixture conduit and pivotally mounting an unbalanced choke valve 2 having a shaft 3, joumaled in the upper por-v tion of the mixture conduit, and a butterfly throttle valve 4 secured to a shaft 5 joumaled in the lower part of the mixture conduit. At one side of the mixture conduit, choke-shaft 3 extends into automatic choke control housing 6 which contains thermostatic. mechanism for yieldingly closing the choke valve under cold starting conditions. Suitable automatic choke mechanism is fully described and claimed in Patent No. 2,085,351 issued to the present inventor. v

Projecting from the lower part of the mixture conduit adjacent throttle valve 4 is an inclined housing I slidably receiving an outer plunger 3 and an inner plunger 9 telescopingly received in plunger 8. Inner plunger 9 has a projecting stem ID to which is secured a switch contacting plate II for cooperating with terminal screws that when the throtle valve is opened to its normal starting position, substantially as in Fig. 3,

These objects and other more detailed objects 5;,

contact plate ll engages-screws [2 to energize the starter circuit. This starter switch mechanism is disclosed and claimed in detail in a Patent No. 2,174,313 issued to the present inventor.

Formed rigidly on choke shaft 3 is a plate l5 and loosely mounted on shaft 3 inside this plate is an eccentric cam element IS. A pintle i1 ad.- jacent choke shaft 3 loosely mounts a bell crank l8 carrying a screw i 9 in one arm thereof for cooperating with cam l6. and having a laterally projecting headed pin 20 at the extremity of its other arm. A link 2| has a slot 22 in its upper portion whichslidably receives pin 20 and, at its lower portion, is pinned at 23 to a crank rigid a recessed portion 21 of the cam is opposite screw l9 and the throttle valve is permited to close to its normal idling position.

In addition, means is provided for positively opening the choke by substantially full opening movement of the throttle valve, as indicated in Fig. 4. This means comprises an inwardly projecting lip 28, on the upper portion of link 2|, which is positioned to engage a projecting portion 29 on plate l to rotate the choke valve in the opening direction. By reference to Figs. 3 and 4, it will be seen that the throttle valve, in its unloading position, as in Fig. 4, is substantially farther opened than is this valve in its starting position, as in'Fig. 3. The difiiculty is that the operator may not be able to distinguish, in the operation of the throttle pedal,

between the two throttle positions shown in these following mechanism is provided: Loosely pivoted on pintle outside of hell crank I8 is a weighted lever element 3| which is normally maintained in the inoperative position, as in Fig. 1, due to its eccentrically weighted lower portion. Element 3| has a finger 32 projecting upwardly therefrom, the finger having an inclined upper edge 33 positioned to be engaged by anoutward lug 34 on choke plate I5, when the choke is closed, to rotate element 3| slightly in a clockwise direction or, in other words, to its operative position. Pivotally mounted on interconnection link 2|, intermediate the ends thereof, is a trigger finger device 35 which is constantly urged in a counterclockwise direction 'by a spring 36 encircling the finger and link 2|. This finger has an inclined upper edge 31 which is disposed toengage an outwardly projecting pin 38 at the lower extremity of element 3|, when this element is moved to its operative position, as in Fig. 2, in the patriot finger 3 5, and the throttle valve is opened substantially to its starting position, as in Fig. 3. Upon slight additional opening movement of the throttle, edge 31 on finger 35 operates by cam eifect upon pin 33 to rotate element 3| slightly in a clockwise direction' (Fig. 3) and free plate I5 and the choke I valve from finger 32. Thus, in the starting poon the finger will clear pin 38 and inner edge 39 of the finger will engage the pin, whereupon the mechanical advantage acting against spring 36 will be greatly increased due to the sharp angular change in the inclined plane or camming action. This snap-over action occurs just prior to engagement of choke plate projection 23by lip 28, as indicated by the broken line position of elements 23 and 35' in Fig. 3. After the snap-over action the

parts

35, 36 and 'no longer apply sensible resistance to further opening of the throttle and the actual opening of the choke for unloading purposes is effected, after the momentary indication thus afforded, by substantially normal pedal pressure,

Accordingly, it will be seen that I have provided effective means for momentarily indicating to the operator that the throttle valve is opened far enough for energizing the starter circuit, but without openingthe choke, and further, the mechanism does not effect the choke valve during the cranking operation nor does it effect throttle opening'movement under normal running conditions when the choke valve is fully opened.

The invention may be modified in various respects as will occur to those skilled in the art and the exclusive use of all such modifications as come within the scope of the appended claims is contemplated.

I claim:

1. In a carburetor, choke and throttle valves, yielding means to close said choke valve for starting, means operated by an opening movement of said throttle beyond a predetermined position to open said choke valve against said yielding means, resilient means connected to said throttle and operatively independent of said choke valve, and a movable abutment arranged to be moved to a position by the closing .of said choke valve to cooperate with said resilient member to resist the opening of said throttle prior to said predetermined position, said resilient member being movable with relation to said abutment after contact therewith by a further movement of said throttle valve beyond said predetermined position whereby the resistance to throttle opening movement is decreased.

2. In a carburetor having a body member,

- choke and throttle valves, a shaft for said choke valve, yielding means to close said choke valve for cold starting, an arm fixed to said shaft, a shiftable abutment mounted on said body member, means movable with said choke valve for shifting said abutment into operative position, mechanism connected to said throttle and having a part adapted to contact said arm as said throttle is moved, openward a predetermined degree whereafter further opening movement of said throttle will cause an opening of said choke valve, said mechanism including a spring pressed element movable therewith having a steep cam surface arranged to contact said abutment as said throttle valve is moved openward and before said predetermined degree has been reached to provide an indicating resistance to throttle opening, said steep cam surface being movable against spring tension out of contact with said abutment by continued opening movement of said throttle.

3. In a carburetor having a body member,

choke and throttle valves, yielding means to close said choke valve for starting, means connected to and operated by an opening movement of said throttle for opening said choke valve against said yielding means, mechanism for indicating starting position of said throttle including a shiftable abutment mounted on said body member, resilient means connected to said throttle and operatively independent 'of said choke valve and arranged to cooperate with said abutment when said throttle valve is opened beyond starting po'- sition to resist such opening movement, said resilient means being arranged to offer substantially reduced resistance when said throttle valve is opened beyond starting position and means movable with'said choke valve for shifting said abutment into operative position as said choke valve is moved to a closed position.

4. In a carburetor. choke and throttle valves, yielding means to close said choke valve for starting, means operated by opening movement of said throttle to open said choke valve against said yielding means, mechanism for indicating starting position of said throttle including an element movable to an operative position by closing of said choke valve, and a resilient device connected with said throttle valve and operable independent of said choke valve for engaging said element as said throttle is moved openward to starting position to yieldingly resist said throttle opening movement, said resilient device being movable with respect to said movable element by continued throttle opening movement beyond starting position to a position whereby the resistance to throttle opening is abruptly and sensibly decreased.

5. In a carburetor, choke and throttle valves, yielding means to close said choke valve for starting, means operable by opening movement of said throttle valve beyond a predetermined starting sition to momentarllyresist such throttle opening movement, and arranged to be rendered le-s effective by farther opening movement of said throttle valve beyond said position.

6. In a carburetor having a body member, a choke and throttle valve, yielding means for closing the choke for starting. means connected t) andoperated by an opening movement cf the throttle valve beyond normal starting position to open said choke valve against said yielding means, mechanism for indicating starting position of said throttle including a spring DYE-879d snap-over device connected with said throttle valve and a depending element carried by said body member, said depending device being positioned by movement of said choke to starting osition for engagement with said snap-over device to momentarily yieldingly resist the throttle opening movement and means for rendering the throttle resistance less effective, said last named means being operated by a continued throttle movement.

7. In a carburetor, choke and throttle valves, yielding means to close said choke valve for starting, means operated by opening movement of said throttle to open said choke valve against said yielding means, mechanism for indicating the starting position of said throttle including an element movable to an operative position by closing of said choke, and a spring pressed pivoted member connected with said throttle and operable independent of said choke, said pivoted member including an inclined face for engaging said movable element as said throttle is moved openward to starting position to yieldingly resist said throttle opening movement, said pivoted member being movable with respect to said movable membertby continued throttle opening movement be yond starting position to a position whereby the resistance to throttle opening is abruptly and sensibly decreased.

' IRVEN E, .COFFEY,