US1489766A - Engine - Google Patents

Description

A ril 8. 1924:

L. S. KEILHOLTZ ENGINE Original Filed March 28 1918 2 Sheets-Sheet 1 A ril 8, 1924;

' L. S. KEILHOLTZ ENGINE Original Filed March 28. 1918 2 Sheets-Sheet 2 .Z-HUEZYIZBT m 5. NW

35/ W2 1i 15 15 QZZUI'JZE fi atented Apr. 122d.

LESTER S. KEILHOLTZ, OF DAYTON, OHIO, ASSIGNOR, BY MESNE A$SIGNMENTS, T DEBUG-LIGHT COMPA, OF DAYTON, OHIO, A CORPOTION OF DELAWARE.

GENE

Original application filed March 28, 1918, Serial No. 225,812. Divided and. this application filed. June 19, 1919. Serial No. 8%,8w.

To all whom it may concern:

Be it known that I, LESTER S. KnILHoL'rz,

a citizen of the United States of America,

residing at Dayton, county of Montgomery, State of Ohio, have invented certain new and useful Improvements in Engines, of which the following is a full, clear, and exact description.

This invention relates to engines of the 10 internal-combustion or explosion type having overhead valve actuating mechanism whereby the operation of the valves will be the same for all temperatures to which the engine is subjected.

This application is a division of my copending application Serial No. 225,312, filed March 28, 1918.

Heretofore it has been the practice to mount the rocker arm bracket directly upon the cylinder head, and, as a con uence of the unequal expansion of the cylin er head,

push rod, and valve stem under various conitions of engine operation, there has been a disturbance of the accurate timing adjustment of the valves, which has resulted in objectionable noise and a loss of engine power at temperatures other than that for which the engine valves were adjusted.

The object of the invention is to simplify the construction of engines of this character, and to provide a construction in which the operation of the engine will take place with the utmost efliciency, irrespective of the heating action of the engine, which tends to disturb the adjustments.

In accordance with this invention, I provide an internal-combustion engine having a valve gear which is normally out of engagement with the valve stem to provide a clearance and is mounted on parts carried by a part of the engine, such as the cylinder, which is cooler than the cylinder head, so as to expand independently of the cylinder head and valve stem, and thereby to compensate for the expansion of the cylinder head and the valve stem.

In accordance with a further feature of the invention the supports carrying the valve actuating devices are mounted on the engine cylinder, in the path of the cooling air and are adapted to secure the cylinder head in place upon the cylinder.

Further obiecte and advantages of the present-invention will be apparent from the bodiment thereof, reference being had to the accompanying drawings.

In the drawings:

Fig. l is a longitudinal sectional view of an engine embodying the present invention, certain parts being broken away for sake of clearness;

Fig. 2 is a view of the engine cylinder, as viewed from the generator end of theengine, and on a larger scale, than Fig. 1, in order to show more clearly the rocker arm bracket construction; and

Fig. 3 is a side elevation of the parts shown in Fig. 2.

Referring to the drawings, 20 designates a base supporting a crank case casting 21. Castin 21 comprises the crank case 21, which lncludes a lubricant reservoir located at the bottom of the casting, and a chamber extending upwardly from the reservoir which provi es a housing for the crank, connecting rod and other moving arts. The crank casting 21 also includes a acket 21 surroundin the upper portion of the crank case, said jacket terminating with a circular flange 21 substantially on the level with the upper end of the crank case 21, and cooperating with crank case 21 to form an annular passage surrounding said crank case for a purpose to be described.

Crank case casting 21 supports crank shaft 24 which carries flywheel 25 provided with fan blades 26, and shaft 2 1 is provided with crank 27 formed integral therewith. Crank case 21 supports cylinder 40, in which is mounted for reciprocation a. piston 41, connected by means of connecting rod 42. to crank 27. Cylinder is provided with radiating fins d3.

Cylinder head dd is supported on the upper end of cylinder 40 and is provided with an inlet 1pc and an exhaust pipe 46. Cylinder liead dd is provided with radiating finsdB and 49.

A rocker arm bracket is supported upon cylinder d0" by means of pedestals 51 and'52. Bracket 50 carries a fulcrum or pivot pin 53 upon which are mounted for oscillation rocker arms 55 and 56, which are constructed to cooperate with intake valve 57 and exhaust valve 58, reepe'ptiyely which are normally retained in seated position by means of springs .59 and 60, respectively. Push rods 61 and 62 actuated by cams 63 one of which is (not shown) carried by cam shaft 65 impart motion to said rocker arms 55 and 56, respectively. Cam shaft 65 is supported for rotation by bearings, not shown, mounted in the crank case casting 21, and carries a gear 68 cooperatin with gear 69 mounted on shaft 24.

rank case casting 21 supports jacket 76 which surrounds the sides of the cylinder and cylinder head; and jacket 7 6 supports jacket 77 which is opened at its upper end and surrounds the upper portion of the cylinder head and parts supported thereon. As the flywheel rotates the fan blades 26 carried thereby will cause the circulation of air down through jacket 77, 7 6 and through the space between the jacket 21 and crank case 21*, and out of the engine between the fan blades.

Attention is directed to the fact that the rocker arm bracket is not mounted upon the cylinder head, as has been the practice heretofore, but upon he cylinder. It has been found that in mounting the rocker arm bracket upon the cylinder head, it is impossible to adjust the valve actuating mechanism with respect to the valve stem, so that the clearance will remain the same for all temperatures to which the engine is subjected. This di'tliculty is due to the unequal expansion of the push rod, cylinder head and valve stem. As the temperature of the engine increases, after the engine has been started from a cold state, the distance from the crank shaft to the upper end of the push rod, to the rocker arm fulcrum, and to the upper end of the valve stem will increase. The cylinder and cylinder head, being so much hotter than the push rod, the upward expansive movement of the push rod will be less in proportion with the result that the clearance will increase as the temperature rises. The. increase in clearance will be objectionable especially in the case of engines of larger sizes, and will result in very incorrect valve timing and in noise. To overcome this dilhcutly, the mker arm bracket 50 is mounted upon pedestals 51 and 52 which are supported by the cylinder which is cooler than the cylinder head, and are spaced from the cylinder head so as to be subjected to the cooling air circulatin around the engine, and thereby to be coole to a temperature lower than the cylinder head and it will be obvious that the temperature of the pedestals is higher than that of the push rod. The pedestals 51 and 52 are formed with threaded lower ends which pass through lugs 44:, carried by the cylinder head, and screw into the cylinder, thereby securing the cylinder head in place upon the engine cylinder. By properly positioning the push rods 61 and 62, pedestals 51 and 52 in their relation to one another and memes to the cylinder head 44 and valves 57 and 58,- it has been found possible-'to'automatically change the relation of the rocker arms 55 and 56 to the push rods 61 and 62 and to bracket 50, in proportion to the upward movement of the valve stems due to the added expansive movement of the cylinder, cylinder head and valve. By thus obtaining a proportionate change of relation the clearance between the rocker arms and the valve stems will be maintained constant for all temperatures to which the engine is subjected. In other words there is a differential between the upward movement of the rocker arm fulcrum and the part of the rocker arm engaged by the push rod due to the expansion of the engine parts, and this differential causes the rocker arm to move in such a manner that the end of the rocker arm opposite the Vill"0 stem moves substantially in accordance with the movement of the valve stem due to expansion of engine parts, so that substantially uniform clearance is maintained. It will be noted that the pedcstais 51 and 52 and the bracket 50 form in eiiect a single support for the rocker arm fulcrum and that this su port is mounted upon but one engine part. Therefore compensation for variations in valve stem clearance is effected in a very simple manner.

While the form of mechanism herein shown and described constitutes a preferred form of embodiment of the invention, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What I claim is as follows:

1. In an air-cooled internal-combustion engine, the combination with a cylinder, a

I separable cylinder head mounted on said cylinder, a portin the cylinder head, and

a valve for said port havin a stem projecting upwardly from the cy inder head and s rin means for holding said valve in c oseposition of sup orting means supported entirely by the cylinder extending upwardly adjacent said cylinder head to a height above the cylinder head, a rocker arm pivotally carried by the supporting means for actuating the valve stem, and a push rod for actuating the rocker arm, said supporting means being spaced from the cylinder head at such a distance as to compensate for uneven expansion of the engine parts whereby to maintain a substan tially uniform clearance between the valve stem and rocker arm durin all conditions of ogeration or non-operation.

2. ii an air-cooled internal-combustion engine, the combination with a c linder, a separable cylinder head mounts on said cylinder, a port in the cylinder head, and a valve for said port having a stem projecting upwardly h om the cylinder head and spring means for holding said valve in closed position, of supporting means supported entirely by the cylinder extending upwardly adjacent said cylinder head to a height above the cylinder head, a rocker arm pivotally carried by the supporting means for actuating the valve stem, and a push rod for actuating the rocker arm, said supporting means comprising a plurality of pedestals and a connecting bracket member, the pedestals of said supporting means being spaced from the cylinder head at such a distance as to compensate for uneven expansion of the engine parts whereby to maintain a substantially uniform clearance between the valve stem and rocker arm during all conditions of operation or non-- closed position, of supporting means supported entirely by the cylinder extending up wardly adjacent said cylinder head to a height above the cylinder head, a rocker arm pivotally carried by the supporting means for actuating the valve stem, a push rod for actuating the rocker arm, a fastening lug on the cylinder head adjacent the cylinder, and said supporting means having means passing through said lug to clamp the same firmly to said" cylin der, said supporting means being spaced from the cylinder head at such a distance as to compensate for uneven expansion of the engine parts whereby to maintain a substantially uniform clearance between the valve stem and rocker arm during all conditions of operation or non-operation.---

In testimony whereof I aflix my signature.

LESTER s. KEILHOLTZ.

\Vitnesses:

J. W. MCDONALD, HAZEL SoLLENBEnoER.

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