2. Description of the Prior Art Marine vessels, as for land vehicles, require the use of a transmission to reverse the direction of rotation of the propeller relative to the output shaft of the motive source for bidirectional operation of the vessel, as well as a neutral setting for engine idle without forward or reverse thrust. Virtually all marine transmissions, whether inboard, inboard/outboard or purely outboard application, are large, very complicated to manufacture and repair, and require an abundance of component parts. It would be desirable, therefore, to provide a transmission capable of fulfilling the demanding requirements associated with marine applications which is lightweight, less costly to manufacture and simple to repair. SUMMARY OF THE INVENTION To this end, I have invented a novel marine transmission comprised of a pair of unidirectional couplings of the hyperboloidal type, each having associated with itself a pinion gear, each of which in tι_ are engaged with a ring get for

driving rotation. The ring gear is connected to the output shaft of the motive source such as an internal combustion engine. The hyperboloidal couplings are each comprised generally of a pair of inner race members rigidly and co-axially connected to a common output shaft, which is the output shaft of the transmission, a pair of corresponding outer race members which are integrally connected to, or formed out of, the respective pinion gears, and a plurality of thrust transmitting rollers disposed between said inner and outer race members, said rollers all being similarly inclined with respect to radial planes and making line contact with each of the inner and outer race surfaces formed by the inner and outer race members, respectively. The couplings are selectively engageable or disengageable to provide forward, reverse and neutral states. The common shaft to which the inner race members of the couplings are connected drive, either directly or indirectly, the propeller. Means are provided in association with both inner race members for coupling and decoupling the inner race members with respect to the outer race members upon selection of forward, reverse or neutral gear. It is an object of the present invention to provide a compact marine transmission which utilizes a minimum number of parts yet which efficiently accomplishes the task of transmitting rotational energy from a motive source to a propeller in either direction selectively. It is also an object of the present invention to provide a marine transmission which has as its principal operating

components a pair of unidirectional couplings of the hyperboloidal type which are alternately decouplable during operation. In accordance with these and other objects which will be apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a partial cross-sectional plan view of the marine transmission of the instant invention shown in the "neutral" state. Figure 2 is a partial cross-sectional plan view of the marine transmission shown in the "forward" state. Figure 3 is a partial cross-sectional plan view of the marine transmission shown in the "reverse" state. Figure 4 is a partial cross-sectional elevational view of my marine transmission shown in the "forward" state corresponding to Figure 2. Figure 5 is a partial cross-sectional elevational view of my marine transmission in the "reverse" state corresponding to Figure 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, Figure 1 shows my marine transmission 10 particularly adapted for use with a sterndrive-type apparatus of a marine vessel comprising a fluid tight housing or casing 12 adapted to receive a transmission input shaft 14 which is connectable to the motive source such as an internal combustion

engine (not shown) . Said input shaft being rigidly and drivingly connected to a ring gear 16, which in turn drivingly engages a first pinion 20 and a second pinion 60, said pinions 20, 60 ^" each being couplable and decouplable, in alternating fashion, with respect to an output shaft 24. Output shaft 24 may connect to a propeller or any intermediate mechanism or component. Interposed between first pinion 20 and output shaft 24 is a unidirectional clutch 22 which may be engaged or disengaged depending upon the position of CAM lobe 30. Figure 2 depicts the position of lobe 30 which will cause thrust transmitting engagement of outer race member, or pinion, 20 with inner race member 26, which in turn is connected for rotation to shaft 24 via splines 28. As can be seen by comparing Figures 1 and 2, inner race member 26 is axially slidable on shaft 24 between the first, engaged position shown in Figure 2 and a second, disengaged position, shown in Figures 1 and 3. Unidirectional clutch 22 is preferably a hyperboloidal type clutch in accordance with my invention disclosed in co-pending U.S. Patent Application Serial No. 07/418,795, the disclosure of which is incorporated by reference herein as though fully set forth herein. Clutch 22 is comprised of an inner race member 26 slidably disposed about shaft 24 by splines 28. Inner race member 26 defines a sub-derivative inner race surface of revolution about axis of rotation R of shaft 24. The outer race of clutch 22 is preferably integrally formed with and defined by an inner bore of pinion 20 and defines a super derivative hyperboloidal surface of

revolution about axis R, and forms a confronting race surface wit inner race surface 32. Inner and outer race surfaces 32, 34 defin an annular volume therebetween in which are disposed a plurality of cylindrical thrust transmitting rollers 40, all being similarly inclined with respect to radial planes. Rollers 40 are supporte axially thereof by an annular shoulder 36 connected to inner rac member 26. Bearing means such as thrust washer 38 may b interposed between the ends of rollers 40 and the shoulder 36 t facilitate low friction sliding between rollers 40 and shoulder 36 during freewheeling of pinion 20 with inner race member 26. Clutch 22 is normally biased into the disengaged position shown in Figures 1 and 3 through the use of biasing means such as coil spring 46 disposed concentrically about shaft 24 and sandwiched between inner race member 26 and transmission housing 12. Lobe 30 has connected thereto a shaft 50 eccentrically positioned. Rotation of shaft 50 causes lobe 32 to rotate eccentrically into position shown in Figure 2, in which the force exerted on shaft 50 by an external source governed by the operator of the marine vessel overcomes the resisting force of spring 46. By so moving inner race member 26, inner race surface 32 and outer race surface 34 are brought into line contact with rollers 40 such that when pinion 20 is rotated by output shaft 12, rollers 40 jam against the inner and outer race surfaces and thereby transmit torque from pinion 20 to inner race member 26, causing shaft 24 to rotate in the forward direction.

CAM lobe 30 may be provided with an outer race 30' and a plurality of ball or roller bearing elements to reduce stresses when said lobe is brought into contact with inner race member 26 in shifting from either reverse or neutral to forward drive. Further, a self-lubricating annular member 33 may be used to provide additional stress relief across the area of contact between lobe outer race 30' and inner race member 26. In so providing, what would otherwise be highly localized disturbances are distributed across a larger area. Pinion 20 is preferably held in position with respect to casing 12 by bearing means such as ball bearing arrangement 44. Further, bearing means such as roller or ball bearings 45 should be used to locate ring gear 16 relative to housing 12. As best seen in Figure 3, lobe 30 may be rotated opposite to that shown in Figure 2, outer race 30' leaves contact with inner race member 26 and bearing means 33, and biasing means 46 urges inner race member 26 to its disengaged, or second, position. As seen in Figure 3, second pinion 60 is decouplably engageable with second unidirectional clutch 42. Unidirectional clutch 42 is preferably a hyperboloidal-type clutch having an inner race member 66 connected for rotation to output shaft 24 via splines 68, yet said inner race member 66 is axially slidable on shaft 24 between a first, engaged position, shown in Figure 3, and a second, disengaged position shown in Figures 1 and 2. Inner race member 66 defines a sub-derivative hyperboloidal surface 72 of revolution about axis R and preferably has connected to its large

diameter end an annular shoulder 76. Preferably, pinion 60 has an inner bore which defines a super-derivative hyperboloidal surface 74 of revolution about axis R. Surfaces 72, 74 define confronting race surfaces and define an annular volume therebetween in which are disposed a plurality of thrust transmitting cylindrical rollers 80. The ends of rollers 80 nearest shoulder 76 are supported by said shoulder 76 axially thereof. Bearing means such as annular thrust washer 78 may be placed between the ends of rollers 80 and shoulder 76 to facilitate low friction sliding therebetween. Inner race member 66 is normally biased into the disengaged position by the use of biasing means such as coil spring 86 sandwiched between inner race member 66 and housing 12. When lobe 30 is merged into contact with annular bearing means 73 of inner race member 66, the force imposed upon shaft 50 overcomes the resistance offered by spring 86 and inner race member 66 is moved into the position shown in Figure 3 wherein rollers 80 cause thrust transmitting engagement between pin:,jn 60 and inner race member 66, which in turn causes shaft 24 to rotate. Simultaneously, inner race member 26 of first clutch 22 has been disengaged and will therefore permit pinion 20 to rotate freely thereabout, which is essential as shaft 24 will rotate in the opposite direction once inner race member 66 is moved into the engaged position shown in Figure 3. Preferably, pinion 60 is located with respect to housing 12 by the use of bearing mean such as roller or ball bearing arrangement 84.

It can therefore be seen that by simply imposing a force in the direction of arrow R-F of Figure 1 clockwise will cause the transmission 10 to transmit rotational energy from shaft 12 through pinion 20 and inner race member 26 to output shaft 24. Under this condition, second clutch 42 is disengaged and permits pinion 60 to rotate freely thereabout. Alternatively, rotating shaft 50 in the counter-clockwise direction as depicted in Figure 3 causes second clutch 42 to assume its engaged position and first clutch 22 to assume its disengaged position, thereby causing shaft 12 to transmit rotational energy, in the opposite direction to that provided by the engagement of clutch 22, to shaft 24, thereby allowing reverse operation of the propeller. It should be noted that rollers 40 and 80 may be inclined oppositely to their orientation described herein (i.e. oppositely skewed) , in which case engagement of clutch 22 will cause reverse direction of shaft 24 to that previously described and engagement of clutch 42 will cause forward rotation of shaft 24. It is to be understood that while I have illustrated and described a certain form of my invention, it is not to be limited to the specific form or arrangement of parts herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown in the drawings and described in the specification.