US1957556A - Fuel pump cut-out - Google Patents

Description

May 8, 1934. o. SCHELLING 57,556

FUEL PUMP CUT OUT Filed April 28, 1932 2 Sheets-Sheet 1 7/ ,1. 4? F 2 1. z 19 2 v 1/ 15 1.5 A T5331 O 14? if I I ll I I H 326 10 .35 16 ff I 47 l j 10 a: l? I r 17 I 1 -37 12L I @gagricfieZZ/uy w. fiiorne Patented May 8, 1934 UNITED STATES PATENT QFFICE 3 Claims.

My invention relates to improvements in fuel pump cut-outs for use in connection with internal combustion engines using fuel under high compression. The primary object of this invention is to automatically release or cut out the action of the fuel pump at a predetermined pressure of the heavy fuel oil which is sprayed into the combustion chamber of the engine and to provide adjustable means by which the pressure at which the cut out mechanism is caused to function can be regulated. Among the advantages attained by my improvement is to entirely avoid the use of a relief valve in the high compression fuel apparatus which in the past has been indispensable and inefficient in operation. This invention is applicable to high compression internal combustion engines of two, four or any number of cycles, the drawings and following description disclosing its use when applied to an engine of four cycle type. Also for the purpose of illustration only the invention is shown and described when applied to an engine of single cylinder type.

In the accompanying drawings forming part of this specification, Fig. 1 is a front elevation of an internal combustion engine with my invention attached thereto, part of the structure being broken away and in section; Fig. 2 is a view similar to Fig. l of a detail showing the valve mechanism (of usual construction) which for the purpose of clearness has been omitted from Fig. l and also omitting the fuel pump and my improvement which is illustrated in Fig. 1; Fig. 3 is an enlarged vertical central section through a detail of my improved cut-out mechanism shown in Fig. 1; Fig. 4 is an enlarged elevation of a detail looking in the direction of line 4-4 of Fig. 3, and Fig. 5 is a cross section taken on the line 55 of Fig. 4.

In the drawings, A designates an internal combustion engine which for the purpose of illustration is conventionally shown of the four cycle type having one cylinder 10, a crank shaft 11, cam shaft 12 and cam shaft drive 13 of usual type. The engine is of Diesel type and adapted to operate byhighly compressed heavy fuel oil delivered by spraying into the cylinder through the inspirator 14, in the usual manner. The inspirator is valve controlled through the action of a rocker arm 15, reciprocable push rod 16, sliding in guides 17, and cam 18 on the cam shaft 12, all operating in synchronism with the rotation of the crank shaft and reciprocation of the piston in the cylinder of the engine to spray fuel oil into the combustion chamber during each power stroke. For the purpose of greater clearness, Fig. 2 illustrates the ordinary parts described, said parts being eliminated from the illustration of my improved mechanism disclosed in Fig. 1, it being understood that on the complete device both sets of mechanism shown in Figs. 1 and 2 are employed.

Referring to Figs. 1 and 3, my improved pump cut-out mechanism consists of the high compression fuel pump B, which receives its supply of heavy fuel oil from the fuel intake passage 20 leading through the distributing valve housing 21 past a check valve 23 and ingress 24 into the cylindrical compression chamber 25 within the pump body. The pump is secured rigidly to a vertical support 26 by bolts 27, said support being suitably mounted upon the crank case 28 of the engine and secured such as by bolts 29. A piston resembling a rod, reciprocates vertically from below through a packing gland 31 and compresses the heavy fuel oil which is drawn into the compression cylinder 25 by the suction stroke of the piston and forced upwardly past the check valve 32, through the connecting duct 33, from which the compressed fuel is forced into the fuel reservoir C or conducted directly by passage 24 to the inspirator 14. Fuel in said reservoir is raised in pressure automatically through the reciprocation of the pump 30, said piston being actuated by the operation of an eccentric on said cam shaft 12.

The fuel medium is injected and compressed to a predetermined high compression in the compression reservoir C, by the pump B and for the purpose of restricting said compression to a predetermined compression so as to operate the engine effectively at all times, I have provided yielding means such as a toggle between the eccentric 34 and the piston 30, said yielding means being regulated so as to flex and cut out the stroke of the piston when the desired pressure of fuel in the reservoir is attained. Said yielding means consists of a pair of toggle elements D and E hinged together by a pintle shaft 35 and hinged at their opposite extremities to the piston 30 by pintle shaft 36, and to the guide sleeve 37 by the pin 3'7. The sleeve is adapted to reciprocate in a cylindrical guide 38 which is mounted upon the supporting element 26 and is revolubly coupled to the eccentric 34 on cam shaft 12 by the crank arm 40 and sleeve pin 39. Thus as the cam shaft 12 revolves, the piston 30 is reciprocated through the action of the guide 37 and said yielding element or toggle. The link elements D and E are held by freely revoluble antifriction rollers 47 on pintle shaft 35, slight- 1y out of longitudinal alignment as shown while normal, that is when adapted to deliver maximum length of stroke to the pump piston. When the links are flexed outwardly from normal position of the links, the stroke of the piston is automatically cut out. This tendency to flex is controlled by adjustable spring retarding means consisting of a lever arm 41 swung by pin 43 from the outer end of a lateral support 42 extending from the main support 26; a coupling link 44 pivoted at its ends to the lower end of lever arm 41 and to the pintle shaft 35, and an adjustable expanding element F. The coupling link 44 plays through a slot in the vertical support 26 and surface plate 46 on said support, and one of its ends is bifurcated to span the link member E (see Fig. 5) and produce an even support on the pintle shaft 35. Link member D resembles a skeleton frame to support the pintle shafts 35 and 36 at four evenly distributed points or bearings and the ends of the pintle shafts are journaled upon anti-friction rollers 47 to guide the link connecting elements vertically when the links are normal, that is while the stroke of the piston is at its greatest length, the peripheries of said rollers turning and bearing against the surface of the bed plate 46. The antifriction rollers 47 which are carried by the pintle shaft 35 and which bear against the guiding support 46 are larger in diameter than the diameter of the rollers 47 which are journaled on the shaft 36 for the purpose of holding the toggle links out of alignment normally. The expansible element F which acts to retard the flexing movement of the links D and E and cut out the stroke of the piston in the pump, consists of a pair of telescopic guide rods 48 and 49, the outer ends of which are pivotally attached, one to the lever arm 41 between its ends and the other to an adjusting lever 50, the latter being pivotally attached between its ends at 51 to the lateral support 42 and having its free end adjusted by an adjusting bolt 52 threaded in the arm 53 on said lateral support. An expansible helical spring 55 is compressed between shoulders 54 on the telescopic members 48 and 49 and its tendency is to hold the links D and E in their longest piston stroke delivering or outstretched position, the greater the spring is compressed by turning the bolt 52 down the higher the pressure of fuel attained in the tank until the links automatically release and cut out the stroke of the piston. To decrease the compression of fuel attained in the fuel reservoir by the pump the bolt 52 is reversed and the tension of the spring decreased. The links will thus flex outwardly more readily under the resistance of the piston and the compression of fuel in the reservoir will be maintained substantially constant.

In operation the parts of the engine function in the usual manner, that is the inspirator and exhaust valve (not shown) perform their functions in synchronism with the movement of the piston of the engine. The pump consequently compresses the heavy fuel oil in the compression reservoir in condition to be delivered to the inspirator and the pressure of fuel developed in the reservoir is regulated so as not to increase beyond a predetermined degree, by cutting out the action of the pump automatically. This cut out action transpires as follows: On the compression stroke of the pump piston the toggle is held in position by spring F, arm 41, link 44, etc. When the pressure on the fuel by the pump becomes greater than the force exerted by the control spring F the toggle will release and cut out the stroke of the pump, this cut out condition continuing for the remainder of the power stroke. The fuel consumed by the engine is drawn from the fuel line, the pressure of which is kept up sufliciently by the amount of trapped air in the fuel reservoir and is replenished with each successive compression stroke of the pump. The compression strokes required of the pump or pumps depend on the number of cylinders em-- ployed in the engine.

In accordance with the patent statutes, I have described the principles of operation of my invention, together with the construction thereof which I now consider to represent the best embodiment thereof but I desire to have it understood that the construction shown is only illustrative and that the invention can be carried out by other means and applied to uses other than those above set forth within the scope of the following claims:

Having described my invention what I claim as new and desire to secure by Letters Patent is:

l. A yielding pitman, comprising, a thrust shaft having a plurality of longitudinal shaft members for transmitting reciprocable motion, a yielding toggle having toggle members pivotally connected together and to the contiguous ends of said shaft members and adapted to allow the toggle to break at a certain predetermined pressure, a pin by which said toggle members are pivotally connected together, a supporting member extending longitudinally alongside of said toggle members, an antifrietion roller journaled on said pin and in rolling contact against said support by which the toggle members are held out of alignment normally, and resilient restraining means tending to urge the toggle members inwardly towards said support into maximum extended position and yieldable to permit said toggle members flexing outwardly when said thrust shaft is subjected to a predetermined thrust pressure.

2. A yielding pitman, comprising, a thrust shaft having a plurality of longitudinal members for transmitting reciprocable motion, a yielding coupling having toggle members pivotally connected together and to the contiguous ends of said shaft members and adapted to allow the toggle to break at a predetermined pressure, a pin by which said toggle members are pivotally connected together, a supporting member extending alongside of said shaft, an antifriction roller journaled on said pin and in rolling contact against said support by which the toggle members are held out of alignment normally, resilient restraining means tending to urge the toggle members inwardly towards said support into maximum extended po- 1 sition and yieldable to permit said toggle members flexing outwardly when the shaft is subjected to a predetermined thrust including means for modifying said restraining means to vary the thrust pressure at which the toggle will flex.

3. A yielding pitman, comprising, a thrust shaft having a plurality of longitudinal members for transmitting reciprocable motion, a yielding coupling having toggle members pivotally connected together and to the contiguous ends of said shaft members and adapted to allow the toggle to break at a predetermined pressure, a pin by which said toggle members are pivotally connected together, a supporting guide extending alongside of said shaft, an antifriction roller journaled on said pin and in rolling contact against said support by which the toggle members are held out of alignment normally, resilient restraining means tending to urge the toggle members inwardly towards said support into maximum extended position, comprising, a coupling link journaled to said pin, a lever arm pivoted to the outer end of said link, a support to which said lever arm is pivoted and resilient means urging said lever outwardly and acting to yieldingly hold said toggle members in outermost extended position including means for modifying the strength of said resilient means.

OSCAR SCHELLING.

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