Patent Publication Number: US-4545336-A

Title: Engine with roller and cam drive from piston to output shaft

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to internal combustion engines, and more particularly to light weight, compact engines suitable for example for powering lightweight (ultralight) aircraft, outbound motor boats, stationary power plants, automobiles, motorcyles, etc. The engine design is capable of utilizing standard four-stroke operation in conventional or diesel applications. 
     There is a need for engines of this type, where extreme compactness and light weight are at a premium; at the same time, maximum power output is desired. No prior engine of which I am aware posseses the highly advantageous features of construction modes of operation and beneficial results characterized by the engine describes herein, and also the lightweight, compact design embodied therein. 
     SUMMARY OF THE INVENTION 
     It is a major object of the invention to provide an improved engine having the above advantages and features of construction. 
     Basically, the engine is characterized by: 
     (a) one pair, at least, of opposed cylinders and pistons reciprocating therein, 
     (b) power and return rollers carried by each of the pistons to reciprocate therewith during piston travel, 
     (c) a power output shaft having an integral and external driven cam located to be driven in rotation by the power rollers in response to power stroke travel of the pistons, the shaft having an axis of rotation, 
     (d) a flange integral with the output shaft and having an internal cam track located to be engaged by the return rollers in response to return stroke travel of the pistons, 
     (e) the power and return rollers having parallel axes of rotation, the return roller axes located closer to the shaft axis than the power roller axes. 
     As will appear, the four stroke engine may typically include a cross head slider and a lateral guide roller also carried by each of the pistons, and guide structure associated with each cylinder for guiding reciprocating movement of said slider and guide roller. For piston strokes produce on revolution of the output shaft. Also, the engine may typically include a mounting shaft associated with each piston, and mounting a power roller, a return roller, a slider and a guide roller. For balance, the power roller and guide roller are located between the slider and return roller, the power roller located between the slider and the guide roller. Further, the mounting shaft typically has a first section carrying the slider, power roller and guide roller, and a second section carrying the return roller, the power roller axis defined by the first section and the return roller axis defined by the second section. 
     In addition, there typically are needle bearings via which said power, guide and return rollers are carried on the mounting shaft; to feed lubricant to the needle bearings, and therebeing a fixed casing having a port via which pressurized lubricant is delivered to the passages as the latter momentarily communicate with said port during piston reciprocation. For compactness, the power output shaft may typically have an I-shaped cross-section normal to the output shaft axis at a location readially inwardly of the guide roller. In this regard, the minimum thickness dimension of said I-shaped cross section is approached by the guide roller and is less than the minimum cross-sectional thickness of the power cam. 
    
    
     These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following specification and drawings, in which: 
     DRAWING DESCRIPTION 
     FIG. 1 is a sectional plan view of an engine incorporating my invention, the piston shown at top dead center; 
     FIG. 2 is a sectional end view taken on lines 2--2 of FIG. 1; 
     FIG. 3 is a view like FIG. 1 showing the piston at bottom dead center; 
     FIG. 4 is a sectional end view taken on lines 4--4 of FIG. 3; 
     FIG. 5 is an elevational view of a complete piston assembly; 
     FIG. 6 is a bottom view taken on lines 6--6 of FIG. 5; 
     FIG. 7 is a section taken on lines 7--7 of FIG. 6; 
     FIG. 8 is an enlarged view, partly in section, showing the piston and cam assembly in operating relation at top dead center; 
     FIG. 9 is a sectional end view on lines 9--9 of FIG. 8; 
     FIG. 10 is a view like FIG. 8, showing the elements at bottom dead center; 
     FIG. 11 is a sectional end view on lines 11--11 of FIG. 10; 
     FIG. 12 is a sectional end view through lines 12--12 of FIG. 1, showing inlet and exhaust valve operation; 
     FIG. 13 is a view on lines 13--13 of FIG. 12; 
     FIG. 14 is a view like FIG. 1, but showing a four cam modification; and 
     FIGS. 15 through 17 are schematics showing multiple cylinder arrangements. 
    
    
     DETAILED DESCRIPTION 
     The internal combustion engine 10 shown in the drawings includes a pair of opposed cylinders 11 and pistons 12 reciprocating in bores 11a therein. A power output shaft 13 rotates about axis 13a, extending generally perpendicularly to the axes of piston reciprocation. Shaft 13 has an integral and external cam as defined by two lobes 14 located to be driven in rotation by two power rollers 15 respectively carried by the pistons, in response to power stroke travel by the pistons toward axis 13a. 
     A circular flange 16 is integral with the output shaft, and has an internal cam track 16a located to be engaged by two return rollers 17 respectively carried by the pistons, in response to travel by the pistons away from axis 13a. As shown, the return rollers fit within a cavity or recess 18 formed in the side of flange 16, for compactness. Track 16a also has two lobe shafts. 
     A mounting shaft 19 is associated with each piston and mounts the associated power roller 15 and return roller 17, as shown. In particular, the axis 17a of rotation of return roller 17 about the shaft 19 is parallel to but offset closer to shaft axis 13a than the axis 15a of rotation of power roller 15 about shaft 19. This is facilitated by construction of shaft 19 to have two parallel sections 19a and 19b, interconnected by offset 19c. See FIG. 7. This construction also enables location of piston 12 closer to shaft axis 13a. Note in FIGS. 7 and 8 that the surface of the power roller 15 closest to the shaft axis engages the driven cam, as at 20, and the surface of the return roller 17 furthest from the axis 13a engages the cam track 16a, at 21. 
     The first section 19a of the mounting shaft also carries a radially elongated cross head slider 22, for guided travel adjacent radially extending guide surface 23a which is arcuate in cross section (see FIG. 6). Surface 23a is defined by a radially extending guide 23 integral with the engine body or cylinder 11. Slider 22 is located at one end of the shaft section 19a, at the outer side of the piston strut 24. Return roller 17 is located at the end of shaft section 19b, at the outer side of piston strut 25. Struts 24 and 25 carry the mounting shaft for reciprocating travel in the direction indicated by arrows 26 in FIG. 5. Power roller 15 and a guide roller 27 are carried between struts 24 and 25, for rotation about the shaft section 19a, as shown. Lateral guide roller 27 rotates independently of roller 15, and between two fixed guides 28, which extend in directions 26 and which may be integral with the cylinder 11. As a result, optimum balance is achieved. See FIG. 6 showing elements 15, 17 23 and 27 located in balanced relation. 
     FIG. 7 shows the fixed (as for example pinned) attachment of the mounting shaft to the two struts, at 24a and 25a. Also, needle bearing sets 32, 33, and 34 support roller 15, 17 and 27 for rotation on the mounting shaft. 
     Note in FIGS. 10 and 11 that the power output shaft is cut-away at 30 and 31, to have an I-shaped cross section of thickness d 1  whereby the rollers 17 and 27 may approach close to axis 13a and in the cut-aways, at bottom dead center position of the piston. Power rollers 15 at that time engage the power cam at locations 32 and 33, having spacing d 2 , where d 2  &gt;d 1 . This also facilitates compactness, since the piston may approach close to the axis 13a (see dimension d 3 ). Also bending strength is not compromised. 
     Turning to FIG. 7, passages 36-39 in mounting shaft sections 19a, 19b and 19c feed pressurized lubricant to the needle bearings, from an oil port 40 in casing 41 (see lubricant supply duct 42). In this regard, as slider 23 travels back and forth, passage 36 in the slider momentarily registers with port 40, to receive a metered amount of lubricant. 
     Finally, in FIGS. 1-4, 12 and 13, the engine also includes cylinder heads 50 defining combustible mixture compression chambers 51; mixture inlet ducts 52; spark plugs 53; mixture inlet valves 54 on push rods 55; springs 56 urging the rods 55 towards cam 56a on shaft 13; exhaust valves 57 on push rods 58, the latter urged by springs 59 toward cam 60 on shaft 13. A propeller 61 may be mounted on shaft 13, as shown. 
     FIG. 14 shows four cams 62-65 on a shaft 13, for operating inlet and exhaust push rods in the event of a staggered firing order, i.e. one cam set dedicated to odd numbered cylinders, and another cam set to even numbered cylinders. Cams 62 and 63 control one cylinder, and cams 64 and 65 control a second cylinder. Shaft bearings appear at 70 in FIGS. 8 and 10. 
     FIG. 15 is a schematic showing the cylinder arrangement about the shaft axis, for the FIG. 14 engine; FIG. 16 is like FIG. 15, but showing a modified cylinder arrangement; and FIG. 17 is a view showing an eight cylinder arrangement.