Apparatus for Opening and Closing Control of a Multi-Carburetor Arrangement

This invention relates to an apparatus for the opening and closing control of a multiple carburetor arrangement of the type in which a plurality of carburetors equal in number to the cylinders in a multi-cylinder internal combustion engine are provided side by side and these carburetors are controlled to open and close in a gang-coupled relationship. This invention has for its object to provide such an apparatus wherein a drum shaft comprising a single common shaft for controlling the opening and closing of throttle valves of respective carburetors through links, throttle levers and throttle shafts can be easily mounted and an accordance mechanism for throttle valve open degrees of respective carburetors can be easily operated.

One embodying example of this invention will now be explained with reference to the accompanying drawings, wherein

FIG. 1 is a front view, partly in section, of one example of this invention apparatus,

FIG. 2 is a sectional view taken along line II -- II in FIG. 1 and

FIG. 3 is an elevational side view of a pulley type throttle operation member.

The illustrated embodiment is a four carburetor arrangement used for a four cylinder engine, and comprises a first carburetor 1a, a second carburetor 1b, a third carburetor 1c and a fourth carburetor 1d disposed side by side at regular intervals. These carburetors 1a1b,1c, 1d comprise carburetor bodies 5a,5b,5c,5d having machine casings 4a,4b,4c, 4d, composed of intake passages 2a,2b,2c,2d and covers 3a,3b,3c,3d, float chambers 6a,6b,6c,6d containing fuel therein and piston type throttle valves 7a,7b,7c7d for controlling the degree of opening of the foregoing intake passages 2a,2b,2c,2d.

Numeral 8 denotes a drum shaft comprising a single shaft which passes through the respective carburetors 1a,1b,1c,1d and is rotatably and tightly supported at its both ends by bearing portions 9a,9b of the carburetor body 5a of the first carburetor 1a and the carburetor body 5d of the fourth carburetor 1d, and numerals 10a,10b,10c,10d denote throttle shafts formed of hollow shafts which are connected, within the respective machine casings 4a,4b,4c,4d of the respective carburetors 1a,1b,1c,1d, to the respective piston type throttle valves 7a,7b,7c,7d through links 11a,11b,11c,11d and throttle levers 12a,12b,12c,12d. Numerals 13a,13b,13c denote adjusting shafts comprising inside the machine casings 4a,4b,4c of the first to third carburetors 1a,1b,1c, shaft portions formed of hollow shafts, and outside respective machine casings, adjusting lever portions 15a,15b,15c, having L-shaped tongue member portions 14a,14b,14c. Numerals 16a,16b denote accordance shafts secured to the drum shaft 8 and carrying channel-shaped tongue member portions which clamp the foregoing tongue member portions 14a,14b through springs 17a,17b and adjusting screws 18a,18b. Numerals 19a,19b denote through openings made in the second and the third carburetors 1b,1c for inserting the drum shaft 8 therethrough and these openings 19a,19b are designed to have somewhat larger diameters than the diameter of the drum shaft 8.

Numerals 20a,20b denote fastening nuts for positioning, for accordance, numeral 21 denotes a pulley-type throttle valve operation member which is rotatably mounted on the drum shaft 8 and is urged by a spring 22 toward the full closing position of the piston-type throttle valves, numeral 23 denotes an idle adjusting screw which is disposed to face a portion of the foregoing throttle valve operation member 21 for regulating the minimum idling open degrees of the respective throttle valves, numeral 24 denotes an operation cable for opening the valve, and the cable is in engagement at one end with the throttle valve operation member 21 and at its other end with an acceleration grip or pedal (not illustrated), and numeral 25 denotes an operation cable for closing the valve, and the cable 25 is in engagement at one end with the throttle valve operation member 21 and at its other end with the acceleration pedal.

Numeral 26 denotes a turning operation shaft which has at one end a channel-shaped tongue member portion 27 clamping the foregoing tongue member portion 14c of the third carburetor 1c through a spring 17c, an adjusting screw 18c and a fastening nut 20c and the shaft 26 has at its other end a turning lever portion 29 in engagement with the foregoing throttle valve operation member 21 and urged by a spring 28 toward the opening position of the throttle valves and the shaft 26 is secured to the drum shaft 8 by means of a fastening screw.

Numeral 30 denotes a supporting plate for installing thereon the respective carburetors disposed side by side, and numerals 31a,31b, and 31c denote sealing members for tightly closing the machine casings 4a,4b,4c of the respective carburetors 1a1,b,1c.

The adjusting shafts 13a,13b,13c and the throttle shafts 10a,10b,10c provided in the first to the third carburetors 1a,1b, 1c are arranged to be respectively fixed together integrally by means of fastening screws 32a,32b,32c and be rotatable in relation to the drum shaft 8.

This apparatus having the above construction can be assembled as follows:

After the respective carburetors 1a,1b,1c,1d are disposed on the supporting plate 30 at predetermined intervals, the first carburetor 1a, the second carburetor 1b and the third carburetor 1c are provided with the throttle shafts 10a,10b,10c and the adjusting shafts 13a,13b,13c fastened together by means of the fastening screws 32a,32b,32c and also the fourth carburetor 1d is provided with the throttle shaft 10d, the pulley-type throttle valve operation member 21 and other parts. Additionally, the accordance shaft 16a is provided corresponding with the adjusting lever portion 15a of the first carburetor 1a, the accordance shaft 16b is provided corresponding with the adjusting lever portion 15b of the second carburetor 1b, and the turning operation shaft 26 is provided corresponding with the adjusting lever portion 15c of the third carburetor 1c and the throttle valve operation member 21.

These constructional parts are disposed to be mounted on the drum shaft 8 inserted through the respective carburetors, and thereafter the accordance shafts 16a,16b, the turning operation shaft 26 and the throttle shaft 10d are secured to the drum shaft 8 by means of the respective fastening screws.

Next, after the constructional parts are thus assembled, the first carburetor 1a and the fourth carburetor 1d disposed at the extreme ends of the supporting plate 30 are fixed by fastening in such a condition that the centers of the bearing portions 9a,9b are in alignment with one another, so that the drum shaft 8 can be turned smoothly, and thereafter the second carburetor 1b and the third carburetor 1c are fixed by fastening.

In this case, the through opening 19a,19b made in the second carburetor 1b and the third carburetor 1c for inserting the drum shaft 8 therethrough are designed to be somewhat larger in diameter than the drum shaft 8 as mentioned before, so that the positioning and fixing operation for the second and the third carburetors 1b,1c can be done very simply and in a short time, without hampering the smooth turning of the drum shaft 8.

In the above embodiment, the bearing portions 9a,9b for the drum shaft 8 are provided on the first and fourth carburetors 1a,1d positioned at the extreme ends, but it can be so modified that these bearing portions 9a,9b may be provided on the second and third carburetors 1b,1c. The gaps between the drum shaft 8 and the through openings 19a,19b may be tightly sealed by the sealing member 31, so that no problems arise.

In accordance work for according the open degrees of the throttle valves 7a,7b,7c,7d, the pulley type operation member 21 is in a first step, adjusted by means of the idle adjusting screw 23 on the fourth carburetor 1d and thereby the idling open degree of the fourth carburetor 1d in set. Thereafter, the adjusting lever portions 15a,15b of the adjusting shafts 13a,13b are operated for adjustment by means of the adjusting screws 18a, 18b provided on the synchronizing shafts 16a,16b and thereby the idling open degrees of the first and second carburetors 1a,1b are set. Then, the adjusting lever portion 15c of the adjusting shaft 13c is operated for adjustment by means of the adjusting screw 19c provided on the turning and synchronizing operation shaft 26 and thereby the idling open degree of the third carburetor 1c is set.

Thus, according to this invention, the drum shaft comprising the single shaft for opening and closing control of throttle valve open degrees in a multi-carburetor arrangement is supported by two bearing portions provided on carburetors in the multi-carburetor arrangement and the remainder remaining carburetors are not provided with bearing action, so that on assembling of the carburetor, the drum shaft can be assembled very simply and in a short time and a favorable turning of the drum shaft can be obtained, and also there is not required any extremely high accuracy in an alignment of the through openings in the carburetor bodies, in the side by side arrangement of the adjacent carburetors, attaching openings in the supporting plate, and others, and thus it is extremely advantageous in working and assembling efficiences. Additionally, the accordance mechanism for the carburetors is disposed outside the carburetor bodies, so that an according operation can be effected extremely simply from the exterior, without detaching the carburetor bodies, and this is remarkably advantageous in practical use.