US2964303A

US2964303A - Carburetor metering adjustment

Info

Publication number: US2964303A
Application number: US756340A
Authority: US
Inventors: Robert J Smith; William F Ott
Original assignee: ACF Industries Inc
Current assignee: ACF Industries Inc
Priority date: 1958-08-21
Filing date: 1958-08-21
Publication date: 1960-12-13
Anticipated expiration: 1977-12-13

Description

Dec. 13, 1960 R. J. SMITH ET AL 2,964,303

CARBURETOR METERING ADJUSTMENT Filed Aug. 21, 1958 2 Sheets-Sheet 1 INVENTORS ROBERT J. SMITH BY WILLIAM F. OTT

AT,TORNEY Dec. 13, 1960 R. J. SMITH' ETAL CARBURETOR METERING ADJUSTMENT Filed Aug. 21, 1958 2 Sheets-Sheet 2 I NVENTORS ROBERT. J; SMITH BY WILLIAM F. OTT

ATTORNEY manufacture.

'CARBURETOR METERING ADJUSTMENT Robert J. Smith, St. Anns, and William F. on, Atrton, Mo., assignors to ACF Industries, Incorporated, New York, N.Y., a corporation of New Jersey Filed Aug. 21, 1958, Ser. No. 756,340

19 Claims. (Cl. 261-51) This invention relates to carburetors for internal combustion engines, especially of the automotive type, and more particularly to carburetors of the type in which fuel supplied from the float bowl of the carburetor to a nozzle of the carburetor is metered by means of a metering rod extending through a metering orifice, the rod being movable to vary the effective sizeof the orifice and to control the flow of.fuel from the bowl to the nozzle.

In certain carburetors of the class described, the metering rod is operated by means of a linkage from the throttle shaft of the carburetor. For proper metering, provision must be made for adjustment of the metering rod relative tothe throttle shaft so that the rod will occupy appropriate positions for various degrees of opening of the throttle valve including the usual slightly open dead idle position. Among the several objects of this invention may be noted the provision of a construction which simplifies the operation of adjusting the metering rod relative to the throttle shaft, allowing for such adjustment by the simple act of moving the throttle valve to fully closed position, without any necessity for any additional operations; and the provision of a construction having the stated characteristics which is economical to In general, these objectsv are attained by providing a lost-motion friction connection in the linkage between the throttle shaft and the metering rod, this connection permitting relative adjusting movement between the parts connected thereby and adapted frictionally to retain the parts in any position to which they may be adjusted. With this lost-motion friction connection in the linkage, adjustment may be accomplished by moving the throttle valve to fully closed position, with accompanying movement of the metering rod in one direction to its limit of movement in that direction during the initial phase of movement of the throttle valve, and with relative adjusting movement of the parts during completion of'movement of the throttle valve. Another object of the invention is the provision of a lost-motion frictional connection invention is incorporated;

, Fig. 2 is an enlarged vertical section taken on lines 2-2 of Figs. 1 and 3;

Fig. 3 is a vertical section taken on line 33 of Fig. 2; Fig. 4 is a view similar to Fig. 2 illustrating a modification, being in section on line 5-5 of Fig. 4;

Fig. 5 is a vertical section taken on line 55 of Fig. 4; Figs. 6-9 are views similar to Fig. 2 illustrating addinite tates Patent tional modifications, Fig. 9 being in section on line 9--9 of Fig. 10; and,

Fig. 10 is a vertical section taken on line 10-10 of Fig. 9. Corresponding reference characters indicate corresponding parts throughout the several views of the drawmgs. Referring to Fig. 1 of the drawings, there is indicated at 1 a carburetor comprising a body 3 formed to provide a mixture conduit 5 and a fuel bowl 7. A fuel bowl cover is indicated at 9. This is formed to provide an air horn 11 for conduit 5. The upper portion of mixing conduit Sis formed as a venturi, as indicated at 13, and below this is the throttle bore 15. In the throttle bore'is a throttle valve 17, which is fixed on throttle shaft 19. Fixed on one end of throttle shaft 19 is a bell crank 21. Connected to one arm 21a of bell crank 21 is an actuating rod 23, which is operated by the usual pedal. A spring such as indicated at 25 connected to rod 23 acts to bias the throttle valve in closing direction (counterclockwise as viewed in Fig. 1). Movement of throttle valve 17 in closing direction is limited by a stop screw 27 adjustably threaded in a lug 29 on the mixture conduit "part of the carburetor engageable by bell crank 21.

Screw 27 normally occupies a position determining a slightly open idling position of throttle valve 17. Screw 27 is adapted to be backed off to allow the throttle valve completely to close.

The carburetor body 3 is formed. with a vertical accelerator pump cylinder 31. A piston 33 is slidable in cylinder 31. A lever 35 is pivoted intermediate its ends as indicated at 37 on top of the cover 9 for rocking movement on-a horizontal axis. A rod 39 connects one end of lever 35 and piston 33. A bendable link 41 connects arm 21b of hell crank 21 to the other end of lever 35, the. arrangement being such that upon opening throttle valve 17, piston 33 is driven down through a discharge stroke, and on closing the throttle valve the piston is pulled up through a charging stroke. A checkvalved inlet for flow of fuel from bowl 7 to pump cylinder31 is indicated at 42; an outlet for exit of fuel from the pump cylinder is indicated at 43. Outlet 43 connects to a passage 45 leading to the mixture conduit.

'T he carburetor has a fuel nozzle 47 extending into the mixture conduit from a high speed fuel passage 49. This passage includes a well 51 at the bottom of the fuel bowl. At the upper end of the well (the entrance to the passage from the bowl) is a metering orifice member 53 in which there is a metering orifice 55. Extending down through the fuel bowl and having its lower end portion extending through the metering orifice 55 is a metering rod 57. As shown, this rod is a three-step rod, the steps being designated 59, 61 and 63, the middle step 61 being a tapered step, but it will be understood that rods with other step formations may be used. The rod extends up out of the fuel bowl through a hole 65 in cover 9 and has its upper end connected to lever 35 by a special connection of this invention indicated at 67.

Connection 67 is a lost-motion frictional connection. As shown in Figs. 2 and 3, it includes a bearing constituted by a grommet 69 having a tubular stem 71 slidable in an elongate slot 73 in the lever 35. Slot 73 is located between pivot 37 of lever 35 and the point where link 41 is connected to the lever, and is preferably an arcuate slot curved on an are centered in the axis of pivot 37. The metering rod 57, at its upper end, has a portion bent to provide an arm 75 extending at right angles from the rod and received in the grommet. The grommet has a head 77 at one end engaging one side of the lever and a cupped circular spring washer 79 secured at its other end engaging the other side of the lever. Washer 79 holds head 77 in frictional en:

gagernent with the lever and is itself in frictional engagement with the lever. Washer 79 is formed with a spring tail 81, the end of which is received in an annular groove 83 adjacent the end of arm 75 of the metering rod. Tail '81 serves two purposes: first, to retain arm 75-of the metering rod in the grommet; second, to bias the metering rod laterally and hold it against one side of the orifice 55 (see Fig. 2). The grommet 69 is slidable in slot 73 in lever 35 between limiting positions determined by engagement of its stem 71 with the ends .of the slot, and is frictionally retained in any position to which it may slide. Arm 75 of the metering rod is rotatable in the grommet to allow for swinging of lever 35 without bending the metering rod and axially slidable in the grommet to allow spring tail 81 to bias the metering rod laterally.

Adjustment of the above-described construction isconveniently carried out by first bending link '41 to obtain the proper stroke of pump piston 33. Then, with the throttle valve 17 open, the metering rod 57 is moved downward relative to lever 35 to bring the grommet 69 to the lower end of the slot 73. Screw 27 'is backed oif to permit the throttle valve 17 to be moved to a fullyclosed position in throttle bore (as distinguished from its normal slightly open dead idle position), and the throttle valve is thenmoved to the fully closed position. This swings lever 35 clockwise as viewed in Fig. l, and drives the metering rod 57 downward. The rod moves downward until its lower end engages the bottom of the well 51, which serves as means for limiting the downward movement for the rod. This occurs before the throttle valve is fully closed. As the throttle valve completes its movement to fully closed position, with accompanying further clockwise swinging of lever 35, the lever 35 swings down relative to the grommet 69, and the latter is in effect raised in the slot 73 and repositioned in the slot at the proper setting for holding the metering rod properly positioned relative to the throttle shaft. Finally, the screw 27 is turned to bring it back into position for determining the dead idle position of the throttle valve. As a result, when the throttle valve is in its slightly open dead idle position (see Fig. l), the lower end of the metering rod is raised from the bottom of well 51 and in proper position for metering fuel at idle (see Figs. 1-3), and as the throttle valve is opened, the metering rod is moved along with the throttle valve to appropriate positions for various degrees of opening of the throttle valve.

Figs. 4and 5 illustrate a modification of the lost-motion frictional connection, in which there is a pin 85 (instead of grommet 69) slidable in the slot 73 in the lever 35. The metering rod 57, instead of being formed with a lateral arm at its upper end, is formed with an eye 87 "receiving the pin 85. The pin has a head 91 at one end engaging one side of the lever 35. A spring fastener 93 retained in an annular groove 95 in the pin engages the other side of the lever 35. Fastener 93 holds head 91 in frictional engagement with the stated one side of the lever and is itself in frictional engagement with the other 'side of the lever. The eye 87 of the metering rod 57 is held on the pin by means of a washer 97 and a spring clip such as indicated at 99 received in an annular groove 101 adjacent the end of the pin. The eye 87 of the meterjing rod 57 has some axial play on the pin, andis biased outward away from the lever 35 for engagement of the ro'd'with one side of the orifice 55 by means of a spring tail 103 formed integrally with the spring fastener 93.

Fig. 6 illustrates another possible modification of the lost-motion frictional connection which is similar to the construction shown in Fig. .2, except that the spring tail "81'is omitted from washer 79, and the arm 75 of the metering rod 57 is biased axially by means of a coil spring 105 surrounding the .arm and reacting-from the grommet 69 against a collar -107 on the'end of arm 75.

Fig. 7 illustrates another, possible modification of :the

lost-motion frictional connection in which the arm 75 of the metering rod extends through the slot 73 in the lever 35 without any grommet, being retained in assembly with the lever by means of a U-shaped spring clip 109 straddling the lever and in frictional engagement with opposite sides of the lever, and having a portion 111 on one side (which may be made like fastener 93 in Fig. 5) received in an annular groove 113 adjacent the end of arm 75 of the rod acting to hold the rod in engagement with one side of the orifice 55.

Fig. 8 illustrates another modification in which a spring washer 115 is interposed between the head 77a of the grommet 69a and the adjacent side of the lever. The stem of the grommet is threaded as indicated at 117, and a frictional washer 119 is applied to the stem of the grommet engaging the other side of the lever, a nut 121 being threaded on the stem backing up the frictional washer 119. The arm 75 of the metering rod 57 is retained in assembly with the grommet 69a by means of a collar 122. Arm 75 is axially slidable in the grommet, and is biased toward the left as viewed in Fig. 8 by a spring tail 123 on the spring washer 115.

Figs. 9 and 10 illustrate another modification in which, instead of having a slot like slot 73 in me lever 35, there is a pin 125 rotatably carried by the lever. Pin 125 has a reduced end portion 127 received in a hole 129 in the lever, being retained in assembly with the lever by means of a washer 131 secured on the reduced end portion of the pin. There is sufiicient looseness between the pin, the washer and the lever that the pin may rotate freely in the hole. The pin has a transverse opening 133, and the upper end of the metering rod 57 extends through this opening, being slidable therein. A spring ring 135 is secured in a recess -137 in the pin surrounding the upper end of the metering rod and in frictional engagement therewith. 'A coil spring 139 surrounds the pin, having one end secured as indicated at 141 to the pin and having an extending end portion 143 engaging the metering rod 57 and biasing the metering rod to swing laterally into engagement with one side of the orifice 55.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. In a carburetor having a mixture conduit, a throttle valve in said conduit, a fuel bowl, a nozzle, a passage from the fuel bowl tothe nozzle having a metering orifice therein, a metering rod movable in the orifice, a linkage connecting the valve and rod for moving the rod in one direction on movement of the valve in closing direction and in the other direction on movement of the valve in opening direction, and means for limiting movement of the rod in said one direction, said linkage including a lost-motion friction connection permitting relative adjusting movement between the parts connected thereby and adapted frictionally to retain the parts in any position to which they may be adjusted, whereby the linkage may be adjusted by moving the valve to fully closed position with accompanying movement of the rod in said one direction to its limit of movement during the initial phase of movement of the valve and with relative adjusting movement of said parts during the completion of movement of the valve.

2. In a carburetor as set forth in claim 1, one of said parts having an opening therein and the other of said parts having a portion slidable in said opening, and means connected with one'of said parts and frictionally engaging the other of said parts.

3. In a carburetor as set forth in claim 1, one of said partsehaving an elongate slot therein and the other of said parts having a portion slidable in said slot from one end thereof to the other, and spring means connected with one of said parts and frictionally engaging the other of said parts for providing a driving connection between said parts.

4. In a carburetor having a mixture conduit, a throttle valve in said conduit, a fuel bowl, a nozzle, a passage from the fuel bowl to the nozzle having a metering orifice therein, a metering rod movable in the orifice, a linkage connecting the valve and rod for moving the rod in one direction on movement of the valve in closing direction and in the other direction on movement of the valve in opening direction, and means for limiting movement of the rod in said one direction, a lost-motion friction connection between an element of said linkage and said rod permitting relative adjusting movement between the rod and said element and adapted frictionally to retain the rod in any position to which it may be adjusted relative to said element, whereby the rod may be adjusted by moving the valve to fully closed position with accompanying movement of the rod in said one direction to its limit of movement during the initial phase of movement of the valve and with relative adjusting movement of said rod and said element during the completion of movement of the valve.

5. In a carburetor as set forth in claim 4, said connection including spring means acting to bias the rod laterally into engagement with one side of said orifice.

6. In a carburetor as set forth in claim 4, said connection including a single spring means for providing friction for the connection and also acting to bias the rod laterally into engagement with one side of said orifice.

7. In a carburetor having a mixture conduit, a throttle valve in said conduit, a fuel bowl, a nozzle, a passage from the fuel bowl to the nozzle having a metering orifice therein, a metering rod movable in the orifice, a lever, a link connecting the throttle valve and lever, a stmotion friction connection between the metering rod and lever, the rod being movable in one direction on movement of the valve in closing direction and in the other direction on movement of the valve in opening disection, and means for limiting movement of the rod in said one direction, said lost-motion friction connection permitting relative adjusting movement between the rod and lever and adapted frictionally to retain the rod in any position to which it may be adjusted relative to the lever, whereby the rod may be adjusted by moving the valve to fully closed position with accompanying movement of the rod in said one direction to its limit of movement during the initial phase of movement of the valve and with relative adjusting movement of said rod and lever during the completion of movement of the valve.

8. In a carburetor as set forth in claim 7, the lever having an opening therein and the rod having a part slidable in the opening, and means for providing friction between the lever and said part of the rod.

9. In a carburetor as set forth in claim 7, the lever having an elongate slot therein, the rod having a lateral arm slidable in said slot from one end thereof to the other, and spring means for providing friction between said arm and said lever.

10. In a carburetor as set forth in claim 9, said spring means also acting to bias the rod laterally into engagement with one side of said orifice.

11. In a carburetor as set forth in claim 7, the lever having an elongate slot therein, a grommet slidable in the slot from one end thereof to the other, the rod having an end portion bent to provide a lateral arm, said arm being rotatable and slidable in the grommet, said grommet having a head at one end engaging one side of the lever, and a spring washer at its other end engaging the other side of the lever.

12. In a carburetor as set forth in claim 11, spring means biasing said arm axially in one direction in the grommet to bias the rod laterally into engagement with one side of the orifice.

13. 'In a carburetor as set forth in claim 12, said spring means being an integral part of said spring washer.

14. In a carburetor as set forth in claim 7, the lever having an elongate slot therein, a pin slidable in the slot from one end thereof to the other, the rod having an eye receiving the pin, the pin having a head at one end engaging one side of the lever, and a spring washer on the pin engaging the other side of the lever and acting to bias the pin axially in the direction for frictional engagement of the head with said one side of the lever.

15. In a carburetor as set forth in claim 14, said eye being slidable on the pin, and said washer having a tail acting to bias the rod laterally into engagement with one side of the orifice.

16. In a carburetor as set forth in claim 7, the lever having an elongate slot therein, the rod having an end portion bent (to provide a lateral arm, said arm extending through the slot and being slidable therein from one end thereof to the other, and a U-shaped spring member receiving the arm straddling the lever and in frictional engagement therewith.

17. In a carburetor as set forth in claim 7, the lever having an elongate slot therein, a grommet slidable in the slot from one end thereof to the other, the rod having an end portion bent to provide a lateral arm, said arm being rotatable and slidable in the grommet, said grommet having a head at one end, a spring washer between said head and one side of the lever, a friction washer on the grommet engaging the other side of the lever, and said spring washer having a tail acting to bias the rod laterally into engagement with one side of the orifice.

18. In a carburetor as set forth in claim 7, said connection comprising a pin rotatably carried by the lever, said pin having a transverse opening, said rod having an end portion slidable in said opening, and means carried by the pin in frictional engagement with the rod.

19. In a carburetor as set forth in claim 18, spring means secured to the pin and biasing the rod to swing on the axis of the pin to hold the rod in engagement with one side of said orifice.

2,711,885 Moseley et al. June 28, 1955