US2169236A - Internal combustion engine - Google Patents

Description

o bl Nu e v n 3 0. Z. FRAZIER INTERNAL COMBUSTION ENGINE Flled Sept 8 1937 2 SheetsSheet 1 Orv Aug. 15, 1939 Gttorneg Aug. 15, 1939 o z. FRAZIER 'L'NTERNAL COMBUSTION ENGINE Filed Sept. 8, 1937 2 Sheets-Sheet 2 Oil 17h Z. Fin z 01- Patented Aug. 15, 1939 UNITED STATES PATENT OFFICE INTERNAL COMBUSTION ENGINE Application September 8, 1937, Serial No. 162,913

3 Claims.

This invention relates to internal combustion engines and particularly two-cycle engines.

An object of the invention is to provide a light compact engine, designed to operate at high speeds and especially adapted to be built in small sizes, suited for driving model aeroplanes or boats.

Another object is to so construct a single cylinder internal combustion engine that its crank shaft may be elongated to comprise a plurality of crank-throws, and a number of said engines may be rigidly secured in side-by-side relation to jointly drive the crank-shaft, thus forming a multi-cylinder engine.

Another object is to so mount a fuel tank on such an engine that the bottom of said tank is formed by an extension of a plate forming the bottom of the crank case.

These and various other objects are attained by the construction hereinafter described and illustrated in the accompanying drawings, wherein:

Fig. 1 is a view of the improved engine in axial vertical section.

Fig. 2 is a relatively transverse sectional view of the engine.

Fig. 3 is a perspective view of the crank shaft, showing its parts disassembled.

Fig. 4 is a sectional view taken on the line 44 of Fig. 1, and showing the spark timer and its controlling cam.

Fig. 5 is a. fragmentary cross-sectional view, taken on the line 55 of Fig. 2, and showing how a fuel feed duct is connected to the crank case.

Fig. 6 is a fragmentary cross-sectional view, taken on the line 68 of Fig. 2, and showing the connection of said fuel feed duct to the engine cylinder.

Fig. 7 is a side elevational view disclosing how a number of the engines shown in Figs. 1 and 2 may be combined to form a multl-cyllnder engine.

Fig. 8 is a front view of a block used in said multi-cylinder engine to properly space the engine units. K Fig. 9 is a sectional view of the same, taken on the line 9-9 of Fig. 8.

In these views, the reference character I designates a cylinder, integrally headed at its upper end and exteriorly formed on its upper portion 'withya suitable number of spaced, annular, heatdissipating fins 2. The usual spark plug 3 is mounted in the cylinder head, so as to form a spark gap in the combustion chamber. The cylinder I surmounts a crankcase 4, serving additionally as a compression chamber for an explosive charge, as is usual in two cycle engines, and a connecting rod 5a extends downwardly from a piston 5, reciprocatory in said cylinder, to engage a crank pin 6 in the crank case 4. Said crank pin is connected by a pair of similar throw arms I to aligned sections 8 and 9 of a crank shaft, said sections being journaled in bearings l0 exteriorly extending from a pair of heads H which form end closures for the chamber 4. Said heads are interconnected and secured tightly in place by a set of bolts l2, extending exteriorly of the crank case. Preferably the throw arms are integrally counter-weighted, as indicated at la.

At one side of the crank case, there is provided a fuel tank I3, and as shown, this tank is formed by a cylindrical wall clamped between an underlying plate l4 and a cover l5, both carried by the engine. Thus the plate I 4 is an extension of. a bottom closure for the crank case 4, being bolted to the latter, as indicated at IS. The cover I5 is integrally connected to the crank case and cylinder by a vertical web H, which further in tegrally carries a duct I8 receiving fuel from a tube 19 disposed axially of the tank l3 and having an inlet end adjacent to the bottom of said tank. The duct is extends from its connection with the tube l9 toward the cylinder, preferably at an upward inclination, the outer portion of said duct beingtapped to adjustably mount a needle valve 20, regulating the fuel flow. The inner or discharging end of the duct opens into a port 2| in the cylinder wall through which air may be drawn, in the illustrated raised position of the piston. Above the port 21 isthe usual exhaust port 22 and opposite to the latter a by-pass 23, rising from the crank case, is adapted to communicate with the combustion chamber, in the lowered position of the piston.

The crank shaft, as best appears in Fig. 3, is an assemblage of parts adapted to be clamped together in working relation. Thus the throw arms I have square holes 24 for receiving the squared ends of the crank pin 6 and square holes 25 for receiving squared ends of the two shaft sections. To adapt the throw arms to be firmly clamped to the crank pin and shaft sections, said arms are centrally formed with slots 26 extending from their counter-weighted ends and intersecting the holes 24 and 25. A clamping screw 27 mounted in each counterweight extends across the corresponding slot 26 to draw the bifurcations of the arm together, and a second clamping screw 28 connects the bifurcations at a point between the holes 24 and 25 to supplement the screw 21. Prior to thus assembling the crank shaft, the connecting rod 5a is of course engaged with the crank pin.

The free end portion of one of the bearings I0 is slightly reduced in diameter to mount a sparktiming unit. This unit comprises a bracket 28, apertured to engage said free end portion and upstanding from the latter and surmounted by a suitable handle. (See Fig. 4.) Pivoted on said bracket is a rocker arm 30, free at one end and extending across the crank shaft, and carrying a fiber lug 3i riding on a cam 32, fixed on the crank-shaft. The free end of the arm 30 carries one of a pair of coacting contact points 33, the other of which is fixed on said bracket. A spring 34 acts on the arm 30, urging the contact points toward an engagement which is permitted by the cam at one point in its periphery. A binding post 35 is electrically connected to the spring 34, said spring and post being, however, insulated from the bracket 29 in any suitable manner. The portion of the bracket apertured to engage the bearing I0 is slit, the slit being bridged by a screw 36, which may be adjusted to allow a rocking of the bracket on the bearing ill, to properly time the spark, while restraining the bracket from accidental shifting.

To combine two or more of the described single cylinder engines, the crank shaft is elongated by adding to it additional throw arms i and shaft sections 9, the latter being squared at both ends to permit such addition. The heads H at the mutually adjacent ends of the crank-cases are removed and replaced by a spacer block 31, which exercises the same sealing and bearing function as said heads and further properly spaces the cylinder blocks to afford a clearance between their fins 2. The first-described bolts 12 are replaced by longer bolts 38, suitable for clamping the engine units firmly together. Thus by combining several of the first-described units in a simple manner, there is built up a multi-cylinder engine, increasing the available power as may be desired.

The described engine operates on the usual two cycle principle, drawing a charge into the crank case 4 when the piston is raised, by-passing such charge into the combustion chamber when the piston is lowered, and simultaneously exhausting products of a preceding combustion and compressing the charge during, and firing it at completion of the following up-strike.

The described sectional form of the crankshaft permits of its manufacture by simple and inexpensive operations, and the entire engine is designed throughout to simplify manufacture and assembly and permit of low-cost quantity production. In miniature sizes, productive of one-half horse power or less, the larger parts may be inexpensively formed as die castings, preferably from an aluminum alloy.

The invention is presented as including all such modifications and changes as come within the scope of the following claims.

What I claim is:

1. In an internal combustion engine, two engine .units each comprising a crank case and a cylinder mounted on the crank case, a crank shaft formed with a crank in each crank case, a spacer interposed between the two crank cases and establishing clearance for said cylinders, and means spanned across the spacer extending exteriorly of the crank cases and outwardly from the spacer for interconnecting the crank cases and clamping said spacer rigidly between the crank cases.

2. In an internal combustion engine, two engine units each comprising a crank case and cylinder, a crank shaft having a crank in each crank case, heads closing the relatively remote ends of the crank cases, and members extendin exteriorly of the crank case and connecting such for clamping said heads on the crank case.

ORVILLE Z. FRAZIER.

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