US1277742A - Internal-combustion engine. - Google Patents

Description

H. C. MUMMERT.

INTERNAL COMBUSTION ENGINE.

APPLlcAxoN FILED ocr.29,19u.

LQWJMQ, Patented sept. 3,1918.

2 SHEETS-SHEET L UQ NT NN y# H. G. MUMMERT. INTERNAL coNNsnoN ENGINE. APPLICATION FILED OCT. 29, HM?.

Patented Sept. 3, 1918 2 SHEETS-SHEET 2.

HARVEY C. MUMMERT, 0F BUFFALO, NEW YORK.

v INTERNAL-COMBUSTION ENGINE.

mamas.

Specification of Letters Patent.

Patented Sept. 3, 1918.

Application led October 29, 1917. Serial No. 198,923.

To all whom t may concern.'

Be it known that I, HARVEY C. MUMMERT, a citizen ofthe United States,'residing at Buffalo, in the county of Erie and State of New York, have invented certain new and useful Improvements in Internal-Combus tion Engines, 4of which the following is a specification.

This invention relates to internal combustion engines. While of general adaptability, it is particularly adaptable to vehicular uses, and among such uses particularly adaptable to airplane uses, and such typical embodiment as herein shown.

Among the several objects of this'v invention are: means for more positive valve control; construction of cylinder, and piston and cylinder cooling means; means for maintaining lubrication and cooling of. piston and piston-rod bearings; means for 4positive lubrication of crank-shaft and pistonrod bearings; and especially radical improvements in form and construction of parts to attain simplicity and interchangeability of standardized parts and more eX- tensive use of standardized parts; and the attainment by the means hereafter shown of eXactness of construction and adjustment. Other objects will be evident to those skilled in the art from the following specification and claims and from the annexed drawings in which,-

Figure l is a side elevation chiefly in central section.

Fig. 2 is a transverse view in section, the left-hand half on the axis of one of the valves and the right-hand half on the axis of a cylinder.

`Fig. 3 is adetail section on awa, 1Fig. 1.

I will irst indicate the main parts, and then describe the several improvements. The main casting or body is shown at 1, the

cylinders at 2, the pistons at 3, the piston rods at'ft, the crank-shaft at 5, the two pairs lof valves for each cylinderat 6 and 7, the

crown casting at 8, the crank case casting at 9, the propeller bearing at 10, thepropeller shaft at 11, a section of the propellerat 12, and the gears connecting the crank-shaft with the propellershaft at 13 and 14.

I will iirst describe my improved valve control. In engines of this high-speed type (the drawings herewith showing an engine having a speed of 2500 R. P. M.) valves which are merely spring-controlled are 1nadequate. The valve operation must be im mediate, positive; for at such speeds, spring lag is suflicient to defeat operation. Mounted in bearings supported by the main casting and the crown casting is a vertical shaft 15 which is driven by miter-gears 16 and 1I, connecting it with the crank-shaft` 5. Upon the upper end of this shaft 15 is a miter-gear 18 in 4mesh with the miter gear 19 on the cam-shaft 20. The cam-shaft 20 is in bearings in the crown casting 8. Upon this shaft 20, to each cylinder, is a double ca1n2l, adapted to act upon the cam-followers`22 and 23 respectively. These camfollowers 22 and 23 are pivoted to rocker-arms 24 which are pivoted on a longitudinal shaft 25, which is rigidly carried by the crown casing 8. The ends of these rocker-arms 24 have'adjustable lugs 26 which are adapted to act upon the upper ends of the stems of the two pairs of valves 6 and 7. Resting over the shaft 25 are leaf-springs 27 the ends of which engagewith the stems of the valves 6 and 7 through any desired means, as for example through bars 28 connecting each pair of stems of valves 6 and/7. The strength of these springs is such that their action in closing the valves is strong and immediate,

-as these springs do not have tomove any other load than the valves and their stems. Moreover, these springs being away from the immediate effect of the heat from the eX- haust gases and being n further 'protected therefrom by the webbing 8a, they do not deteriorate from heat action.

It will now be seen that the action of the rocker-arms 24 .is positive and positively synchronized to the piston action, so that there can be no lag or valve opening at any speed, and this positive means for openino the valves permits the use of springs 2? which render the closing of the valves sub-I stantially equally positive and immediate, since their only action is to close the valves and are not encumbered with an other weight. i

I will neXt describe the cylinder and piston` construction and the cooling means for the same. Heretofore it has been the practice, in engines of this type, to bore the casting for the cylinder and to have the cylinder supported throughout its length by the casting and to have the water .jacket space exterior thereto. With such construction there are necessarily two thicknesses of metal between the cooling medium and the interior ofthe cylinder and necessarily an interposed .joint- 50 which is driven by the shaft 15.

between the two thicknesses of metal which acts in a considerable measure to reduce the heat conduction. My improvement consists in supporting the cylinders 2 at their upper 5 peripheries by flanges 29 which rest in flange seats 230 in the main casting (see especially Fig. :2) and held in place by the crown casting, and by annular lug supports 3l integra'l with the main casting, thus forming l0 the cooling space for the Huid of the cooling` system. By this means the cooling fluid contacts the cylinder directly Without the intervention of any other metal than the cylinder and without any joint, and consequently the cooling effect is more immediate and direct. And this construction leads to the next improved feature ofcoohng means.

The pistons are provided with the interiorI webbing whch form air-spaces between the piston Walls contacting the cylinders and f the piston-rod bearings. These areas have openings and 35 into the interior of the pistons; and thus the interposed air area between the piston Walls and the bearing portions serves materially to lessen the heat conduction to saidbearings. Thewvebbing 33 also acts as a conductor for the heat in the piston crown, carrying it to the parts of Slthe piston Walls directly cooled by the medium in the area 32. Furthermore, the bearing of the piston rods in the pistons is tubular and open at both ends, as shown at so that the contained air is in direct contact 35 with the portion of the cylinder Walls cooled directly by the cooling medium in the spaces 32. This prevents the heat from destroying the lubrication of the piston and piston-rod bearings, Which are the bearings most diiicult of lubrication that is proper and continuous, especially in airplane engines which must be capable of long-continued action under most dilicult conditions. I

Next I will describe my improved means -of lubricating and lubricant-cooling ofthe bearingsbetween thecrank-shaftand piston-rods, Situated adjacent the bottom of the crank casing` where the contained oil is in the coolest condition is an oil-pump 37 Feed pipes (not shown) head from said pump and discharge directly over the oil rings 38 on the crank-Shaft 5. These citi-ings have inturned {iangcs 38 and leading from the recesses thus formed are oil ducts 3i) which lead directly to the crank-shaft, piston-rod bearings at 40. The oil pumped up and delivered into the rings 38 is centrifugally forced into the ducts 39, so that the bearings 'are positively and continuously lubricated and cooled.

The next feature of my invention relates to Siiriplification and standardizing of parts and to means for securing exact construction, adjustment in assembling and adjust "crank-shaft is mounted in standard antifriction bearings l1. The inner one of these bearings fits into an annular seat 42. The other bearings lit into annular rings or bushings lf3, which in turn fit into annular lugseats M on the main casting. The inner bearing is hele in place by a clamp-plate and the bushing Ll?) are held by setscreivs 46.

' Referring'now especially to Fig. 3 in connection with the other gures, it Will be seen that I provide antifriction bearings for the crank-shaft at desired points between cranks. In order that these bearings may be put to place and adjusted before the crank-shaft is put in place in the main casting, I provide the following means: The internal diameter of the ring casing of the antifriction bearings L.Ll here used is sufficiently large to permit the casing to be slipped over the bends of the crank. When slipped to place, segments 41a and 41D Which have external flanges to engage over the edges the bearings 41 and the internal surfaces of which make a close lit with the crankshaft and which are drilled and threaded to receive Screws ll1, are slipped into place in break-joint position and are then secured together by the screws 41.

Thus the crank-shaft and its bearings may be assembled and adjusted before putting to place in the main casting; and when. put in place the bushings are secured and the piston-rods attached and adjusted.l This not only simplifies assembling and adjustment of pai-its, but permits accurate machining ofthe main casting; for it will be seen that, with this construction, the boring-s of the4 main casting to receive the crank-shaft are all concentric, so that 'the alinement of parts may be made substantially absolute. And this same general improvement is applied to the cam-shaft 20. The shaft, its bearings and cams are all adjusted to place and then inserted in a single borin in the crown casting 8, which has annu ar lugs substantially the same as the lugs above described for the bearings of the crankshaft. It will be understood, of course, that the gearlt) is put in place and Secured to the shaft 20 after the said shaft and its bearings are in place.

These improvements, with former construction methods which required a large part of the assembling and adjusting within the castings, render possible the successful employment of American methods of interchangeable construction and machine manufacture, which eliminate to the last, degree hand fitting and the employment of skilled labor.

It will be seen that the shaft 15 drives the pump e? which maintains the circulation rae Y magnetos (one being shown in outline at 50) through the gears 48 and 49.

'Having thus described my invention, I

` claim 1. in an engine of the type described, the combination With inlet and exhaust valves, and a cam-shaft, of a rocker arm acting upon the ste-ms of both of said valves, cams on said camshaft bearing against and positively actuating said rocker arm on both movements, and springs for .closing said va ves.

2. in an engine of the type described, the combination with inlet and exhaust valves, vand a cam-shaft, locatedvbetweenthe valve stems, of a rocker arm pivoted upon ashaft parellel' with and above said cam-shaft and adanted tovact upon the stems of both of said valves, double cams on said cani-shaft bearing against and positively actuating said `rocker-arm in both directions, and springs for closing said valves.

In an engine of the type described, the i combination with inlet and exhaust valves,

of a camshaft, a crown casting in Which said cani-shaft is journaled, a rocker-arm shaft 1n .said crown casting lylng above and parallel with said cam-shaft, a rocker-arm on said rocker-arm shaft, double cams on said cani-shaft positively actuating said rocker-arm in both directions of movement, adjustable mea-ns on said rocker-arm engaging the stems of said valves, and springs over said rockerarrn shaft having their free ends mediately connected to the stems of said valves to close said valves.

HARVEY C. MUMMERT.

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