US2413590A - Arcuate piston - Google Patents

Description

R. L. SNYDER ARGUATE PISTON Dec. 31, 1946.

Original Filed Aug. 5, 1943 2 SheetsSheet 1 GHQ-neg 13%.31, 1946. LSNYDER 2,413,590

ARCUATE PISTON v Original Filed Aug. 5, 1945 2 Sheets-Sheet 2 BLGWE/E Inventor fi'ziilanil.5rgder Z. W

Gltorneg Patented Dec. 31, 1946 ARCUATE PISTON Richard L. Snyder, Glassboro, N. J., assignor of one-fourth to Henrietta B. Snyder, Glassboro, one-fourth to Richard L. Snyder, Jr., Princeton, and one-fourth to Christopher L. Snyder,

Metuchen, N. J.

Original application August 5, 1943, Serial No. 497,420. Divided and this application March 27, 1945, Serial No. 585,139

2 Claims.

This application is a division of my copending U. S. application, Serial No. 497,420, filed August 5, 1943, entitled Internal combustion engines.

This invention relates generally to internal combustion engines and more particularly to valveless internal combustion engines having at least one continuous toroidal cylinder cavity including therein at least one pair of double ended arcuate pistons disposed in mutually cooperative rotary reciprocative relation.

The preferred embodiment of the invention to be described in detail hereinafter utilizes relative reciprocative motion of double ended pistons combined with absolute rotary motion of said pistons for transmitting rotary motion to a drive shaft. Power is transmitted through a translating system, comprising connecting rods journaled to said pistons and to a conventional crank shaft, and crank means secured to the drive shaft and journaled to said crank shaft. In operation, each cylinder comprises the space intermediate adjacent ends of any two of the double-ended pistons within the continuous toroidal cylinder cavity. An explosive mixture is introduced into the space intermediate the ends of each of the two pistons progressing past one or more fixed valveless intake ports, the mixture is then subjected to compression, and the compressed mixture is next subjected to an ignition device which explodes the compressed gas. The exploded mixture delivers power which drives the particular pair of pistons in relative opposite directions, thereby providing reciprocative piston motion with resultant rotary motion of the drive shaft. 'As the rotary reciprocative motion of the pistons again moves the adjacent faces thereof toward each other, the rotary motion of the pistons brings the space intermediate said pistons adjacent one or more fixed tion is to provide a counterbalanced double-ended arcuate piston having a plurality of piston rings fitted thereto, and arranged to rotate within a continuous toroidal cylinder cavity.

The invention will be described in further detail by reference to the accompanying drawing of which Figure 1 is a cross-sectional elevational view of one embodiment thereof taken along the section lines I, I, of Figure 2 which is a cross-sectional view of. the same embodiment taken along the section line 11, II of Figure 1;

Figure 3 is an enlarged fragmentary cross-sectional view of a portion of the cylinder cavity showing the ring bearing-gas seal.

Similar reference characters are applied to similar elements throughout the drawings in order to illustrate better and simplify the accompanying description thereof.

Referring to Figures 1 and 2, the preferred embodiment of the invention is shown as a component of a four-stroke-cycle engine having means defining a single toroidal cylinder cavity having four pistons disposed therein. The means defining the toroidal cylinder cavity comprise a first split casting portion I having a keyed portion which engages a complementary keyway in a second split casting portion 2. The two casting portions l, 2 are clamped together by means of bolts which pass through coincidental apertures 3 equispaced around the peripheral edges of the circular complementary casting faces adjacent the keyed portions thereof. The castings I, 2 include cut-out portions for providing a water jacket for cooling the cylinder cavity walls. The castings also include intake and exhaust apertures 4, 5, respectively, which are connected to suitable intake and exhaust manifolds 6, I, respectively.

The opposite ends of the castings l, 2 each are journaled to a main drive shaft 8. Fixed gears 9, H! are adj'ustably secured to opposite end portions of the castings l, 2, respectively. Adjustment of the angular position of the gears 9, H1 is provided by a radially extending arm H, secured to both of the gears. The gears may be clamped in any predetermined angular position by means of clamping bolts l 2 having external wing nuts l3. The bolts extend through the gears 9, l0 and through slots in the adjacent end portions of the casting l, 2.

A spark plug, or glow plug, l4 extends into a spark plug port, proportioned therefor, which opens into the cylinder cavity. Connections for the spark plug M are made to a high tension ignition coil I5. A battery. or other source of ignition potential I6, is connected to the primary circuit of the ignition coil l5 through a conventio ignition contactor ll which is operated by a earn it. The cam i8 may be mounted on one end of the drive shaft 8, or may be actuated in any other known manner. If a glow plug is used, it may be energized continuously from the battery it, and ignition timing provided by piston position.

The drive shaft 8 extends centrally through the castings I, 2 normal to the plane of the cylinder cavity. An external flywheel l9 may, if desired, be secured to the opposite end of the drive shaft from the ignition cam H3. The flywheel i9 may include gear teeth 20 for drivinga load, and for cooperation with a starter motor of conventional type.

Four pistons 2|, 22, 23, 24 are disposed within the cylinder cavity. These pistons are arcuate in shape and double-ended to provide four cylinders intermediate each two adjacent piston faces. The pistons include conventional .piston rings 25 and-a novel counterbalance arrangement for minimizing radial thrust between the peripheral faces of the pistons and the interior of the cylinder cavity. The pistons 2|, 22, 23, 24 are pivoted on corresponding main connecting rods 26, H, 28, 29, respectively, which as illustrated comprise a pair of double-ended rods each floated upon the main drive shaft 8.

Considering the piston 2 l, for example, the piston casting includes rotatable bearings 3|), 3| in which a piston pin 32 is journaled eccentrically. A. counterweight 33, is secured to the rotatable bearings 39, 3|. One end of the corresponding main connecting rod 26 is journaled to the center portion of the piston pin 32 intermediate the internal ends of the piston bearings 30, 3|. It will be seen that normal radial thrust of the piston due to rotation thereof within the cylinder cavity will be compensated for by means of the resultant radial thrust of the counterbalance 33. Radial thrust of the counterbalance 33 will rotate the piston bearings 38, 3| counterclockwise, thereby increasing the radial thrust of the piston pin 32 in its bearing in the end of the con- A gas seal for the inner peripheral slot comprises a split-ring hearing which extends into the slot and includes apertures having flexible faces for receiving the corresponding connecting rods. The split ring bearings include two separate sets of ball'bearings H, l2 which contact raceways on the sides of a cylinder slot. The two portions '13, M of the cylinder bearing are adapted to reciprocate with respect to each other while at the same time providing an effective gas seal between the reciprocating portions and around the sides having the ball bearings in contact with the cylinder cavity bearing raceways.

As explained. heretofore, thefour pistons 2 I, 22,.

25, respectively, are pivoted on corresponding main connecting rods.v 26, 21 2d, 29, respectively.

The first andth- ird connecting rods 26, 28 may comprise a unitary or rigid structure which is journaled on the main drive shaft 8. Similarly, the second and fourth connecting rods 21, 29 may comprise a second unitary or rigid structure also journaled on the main drive shaft 3 adjacent the first and third connecting rods. A pair of cocentric crank shafts 34, 35 are interposed be tween the inner peripheral limits of the cylinder cavity and the main drive shaft 8. The axial portions of the first and second crank shafts 34, 35, respectively terminate at their ends in pinion gears 35, 3? which engage respectively the fixed gears Hi, 9, respectively. The eccentric portions of the crank shafts 34, 35, respectively,'are each journaled to receive two auxiliary connecting rods which, in turn,-are journaled to adjacent main connecting rods.

For example, the first eccentric crank shaft 34 is journaled to a first auxiliary connecting rod 38 which, in turn, is journaled to the first main connecting rod 26. Likewise, a second eccentric portion of the first eccentric crank shaft 34% is journaled to a second auxiliary connecting rod39 which is journaled to the fourth main connecting rod 29, The wrist pin for the first main connecting rod 23, as shown in Figure 1, is held in a bracket 48 secured by bolts 4| to the side of the main connecting rod. The bracket to terminates in a forked portion 42 which receives the first auxiliary connecting rod 38 and which is pivoted thereto by means of a wrist pin 43. The second, third and fourth main connecting rods are similarly journaled to corresponding auxiliary connecting rods which, in turn, are journaled to either the first or second eccentric crank shafts 34, 35 as explained heretofore. As a matter of convenience, both the main and auxiliary connecting rod bearings may be of the conventional split bearing type to facilitate assembly and replacement thereof. Similarly, other bearings described herein may be-of the split type for the same reason.

The axial portions of the first and second crank shafts 34, 35 are also journaled in cylindrical cranks 44, 45 which are disposed intermediate the main connecting rod bearings and the fixed gears 9, i ii. The two cylindrical cranks 4 3, 45 are both keyed by means of keys 4B, 47, respectively, to the main drive shaft 8.

It will be seen that relative reciprooative motion of the four pistons 2 I, 22, 23, 24 will provide similar reciprocative motion of the corresponding main connecting rods 26, 28 with respect to the remaining pair of connecting rods 21, 29. Considering only the main connecting rods 26, 29; relative reciprocative motion thereof will provide rotary motion of the first crank shaft 34 due to the coupling provided between the main connecting rod and the eccentric crank shaft by means of the auxiliary connecting rods 38, 39, respectively. Since the rotary motion delivered to the eccentric crank shaft 34 will be transmitted-to the corresponding pinion gears secured to the axial ends thereof, the pinion gear will rotate about the fixed gears 9, Hi. The rotation of the pinion gears about the fixed gears will thereby provide rotary motion of the cylindrical cranks 44, 45 keyed to the main drive shaft 8, and of the of the mainconnecting rods 25, 29 coupled thereto.- Since the first and fourth main connecting rods 26., '29, and the thirdand second connecting.

rods 28;, 27 rigidly coupled respectively thereto,

are caused to rotate about the axis of the main drive shaft 8, the corresponding pistons 2|, 22,

23, 24 will also rotate about the axis of the center shaft 8. It therefore will be seen that the pistons have relative reciprocative motion with respect to each other-and, in addition, have rotary motion along the toroidal cylinder cavity due to the travel of the pinion gears around the complementary fixed gears secured to the cavity structure.

Similarly, the ring bearings providing the gas seal within the slotted inner periphery of the cylfinder cavity will rotate as the corresponding connecting rods passing therethrough rotate about the. main drive shaft 8. Also, the two portions of the split bearing-gas seal will reciprocate with respect to each other in the same manner and at the same time as the adjacent connecting rods and pistons reciprocate with respect to each other.

The locations of the intake and exhaust ports 4, 5, respectively, with respect to the location of the ignition plug Hi, are clearly illustrated in Figure 2. If we consider a typical four-strokecycle insofar as the cylinder intermediate the third and fourth pistons 23, 24 is concerned, clockwise rotation of the pistons, as indicated by the arrow, will provide gas intake to the cylinder from the intake manifold ii through the intake ports l, since in this position the third and fourth pistons 23, 26, respectively, are moving away from each other. As the clockwise rotation of the pistons progresses, the pistons commence to move toward each other, due to the reciprocative motion thereof, and at a point substantially coincidental with the ignition plug E4 the com-- pression of the explosive mixture between the pistons reaches a maximum value, The ignition provided by the ignition device 84 explodes the compressed gases, delivering power to the pistons tends to drive them farther apart, thereby delivering energy to the corresponding main connecting rods 28, 29. When the pistons 23, 2 1, reach a position approximately coincidental with the illustrated position of the piston 22, as shown in Figure 2, they commence to move toward each other again, thereby providing pressure for exhaustion of the exploded gases through the exhaust ports 5 and the exhaust manifold 7. After the cylinder has passed, the exhaust ports 5, the pistons 23, 2:! again begin to move apartand pass the intake ports 4 for a repetition of the four-stroke-cycle thus described.

If desired, a scavenging blower 50 may be connected to one or more of the exhaust ports to facilitate scavenging of the cylinder during the exhaust stroke. Any conventional type of carburetor 5l' and intake manifold connection 52 may be provided which will furnish a suitable explosive mixture to the intake ports 5. Similarly, forced intake of the explosive gaseous mixture may be provided by applying pressure to force the mixture from the carburetor through the intake ports 4 when they are uncovered by the several pistons.

It will be seen that the cylinder intermediate each pair of double-ended pistons will follow the same four-stroke-cycle as that described heretofore, and that a single set of intake ports, exhaust ports and a single ignition plug will provide similar operation for each of the successive cylinders passing these points. Therefore, it will be seen that each complete revolution of a particular piston about the main drive shaft 8 will occur during four complete four-stroke-cycles of the cylinders intermediate the various pistons. Since the gear ratio between the pinion gears 36, 3'! and the fixed gears l9, 9 respectively, are selected to be of one to two ratio, the main drive shaft will be turned by the cylindrical cranks 44, 45, through one complete revolution as each of the pistons turn through one complete revolution, thereby providing four explosions of the gaseous mixture for each complete revolution of the main drive shaft.

The external flywheel l9 may, if desired, be omitted, since considerable inertia is provided by the relatively heavy cylindrical cranks 44, which are keyed to the main drive shaft 8.

Oiling of the various bearings and moving surfaces described heretofore is provided by a central oil pump 54 of conventional design. The oil under pressure from the pump 54 is introduced, for example, into the end of the main casting i and passes therethrough through an oil duct 55, The bearing 55 in the end of the main casting l includes a slotted portion 51 which coincides with a hole 58 extending into the main drive shaft 8. The hole 58 terminates in a longitudinal hole 59 which extends substantially the full length of the main drive shaft 8. Radial holes, connecting the interior hole 59 of the main drive shaft to the periphery thereof, are

provided at each of the bearings 56, 6| of the main connecting rods. The main connecting rod bearings Gil, 6! each include slotted portions 62, 63, respectively, which connect to radial oil ducts 55, within the corresponding main connecting rods. The radial oil duct 64 in the main connecting rod 26 extends the full length thereof to supply oil to the piston pin 32 of the piston 2|. The wrist pins 43, between the auxiliary connecting rods and the forked bracket bearings 42, are lubricated through the duct 65 in the cylindrical crank 44 and the longitudinal duct 66 in the crank shaft 35, and thence through longitudinal ducts in the auxiliary rods. Similarly, a portion of the oil circulating through the radial duct E l is diverted within the piston 2| to lubricate the surface faces thereof adjacent the piston rings 25. Lubrication for the eccentric crank shaft bearings is provided by a radial duct 65 extending through the cylindrical crank 44 to the axial portion of the eccentric crank shaft 35 journaled thereto, as explained heretofore with respect to the wrist pins. Lubrication for the bearing in the end of the auxiliary connecting rods journaled on the eccentric portion of the crank shaft is provided by a longitudinal oil duct 86 through the center of the eccentric crank shaft.

Figure 3 shows, in cross-section, the double sealing rings 13, M, which provide a gas seal for the slot on theinner peripheral surface of the toroidal cylinder cavity. Each of the rings are apertured to receive difierent ones of the several main connecting rods, as shown in Fig. 1. The sealing rings include polished complementary surfaces i5, 'e which provide a satisfactory gas seal for the cylinder cavity while permitting relative reciprocative motion of the two rings. The sealing rings are arranged to revolve with respect to the cylinder cavity as the main connecting rods which pass therethrough revolve about the main drive shaft 8. The sealing rings are accurately centered adjacent the cylinder cavity slot by means of the ball or roller bearings ll, 12 disposed in bearing guide channels TI, 18. One sealing ring M is split and is provided with an expanding spring member 19 disposed intermediate the sealing ring and the split ring portion 80. The expanding spring member is mor- 7 tised'to-the main portion of. the sealing ring HI in any convenient manner to prevent substantial gas leakage. The continuous pressure provided by the spring member 79 provides uniform contact between the complementary surfaces of the reciprocating sealing rings, and also constitutes a simple and effective means for compensating for incidental wear of either of the reciprocating rings, or the cylinder cavity guides therefor. Additional springs 8|, 82 are interposed in slots in the cavity wall to exert pressure on the bearing portions it, till, respectively. The split sealing ring is preferably constructed so that internal pressure aids the spring member H to improve the gas seal.

It should be understood that these reciprocating sealing rings may be employed to provide the actual power transmission means between the rotary reciprocating pistons and the eccentric crank shafts. It will be seen that the ball bearing arrangement for floating the sealing rings upon the inner peripheral wall of the cylinder cavity provides a bearing surface which effectively prevents radial thrust of short connecting rod members which may be provided to connect the individual pistons to corresponding ones of the sealing rings. This arrangement saves the space ordinarily required for the main connecting rods which, as shown in Figs. land 2, are journaled to the main drive shaft, and thereby permits relatively heavier main drive shafts and eccentric crank shafts to be employed in engines of predetermined cross-sectional dimensions.

Thus the invention disclosed herein comprises a toroidal type internal combustion engine including one or more toroidal cylinder cavities each having a plurality of arcuate double-ended pistons disposed therein in mutual rotary reciprocative relation. A novel piston counterbalancing arrangement reduces cylinder and piston wear.

I claim as my invention:

1. A counterbalanced piston for a rotary engine comprising a double-ended arcuate piston shell portion, a pair of eccentrically apertured bearings having their outer surfaces journalled in said shell portion, at least one counterweight pivoted on said outer surfaces of said bearings and disposed to rotate with said bearings within said shell portion, a piston pin journalled in said eccentric bearing apertures, and journal means for connecting said piston pin to an external utilization device.

2. A counterbalanced piston for a rotary engine comprising a double-ended arcuate piston shell portion, piston rings on the periphery of said shell portion, a pair of eccentrically apertured bearings having their outer surfaces journalled in diametrically opposite sides of said shell portion, at least one counterweight disposed within said shell portion and pivoted to rotate with said diametrically disposed bearings, a piston pin journalled in said eccentric bearing apertures, and means for connecting said piston pin to an external utilization device.

RICHARD L. SNYDER.

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