Abstract: A variable-stroke crank mechanism has a crankshaft rotatably supported in a casing for relative rotation about an axis with a crankpin displaced out of alignment with the axis. An eccentric collar is rotatably mounted on the crankpin for revolving around the axis in response to the relative rotation of the crankshaft with respect to the casing to reciprocally move an actuator relative to the casing. A stroke adjusting mechanism for adjusting angular displacement of the eccentric collar on the crankpin comprises an internal ring gear integral with the eccentric collar concentrically with the crankpin, a planetary pinion rotatably mounted on the crankshaft and meshing with the internal ring gear, a sun gear meshing with the planetary pinion, and a stroke adjusting shaft rotatably disposed axially in a portion of the crankshaft and coupled to the sun gear, whereby the stroke adjusting shaft is adjustable in angular displacement to adjust a stroke of reciprocating movement of the actuator.

Abstract: A variable-stroke radial-plunger-type apparatus for use as an air compressor, for example, has a main shaft rotatably disposed in a casing assembly, an eccentric collar angularly movably mounted on a eccentric crankpin of the main shaft, and a coupling ring angularly movably mounted on the eccentric collar. A plurality of radial plungers with inner ends coupled to the coupling ring are slidably fitted in respective cylinders that are rockably supported it the casing assembly. The angular movement of the eccentric collar on the crankpin is adjusted by a stroke adjusting mechanism. The coupling ring can be positioned with respect to the main shaft and the casing assembly by a W-mechanism. The W-mechanism may comprise external and internal gears or pulleys and sprockets.

Abstract: A radial-plunger-type hydraulic pump or motor includes a W-mechanism comprising a first internal gear relatively rotatably mounted on a main shaft, an external gear rotatably mounted on a supplementary shaft and held in mesh with the first internal gear, and a second internal gear rotatably mounted on an auxiliary shaft and held in mesh with the external gear. The first and second internal gears have the same number of gear teeth, and the supplementary shaft and the auxiliary shaft can revolve around the main shaft. When the auxiliary shaft revolves around the main shaft while the first internal gear is being held against rotation, the second internal gear does not rotate about its own axis, but revolves with the auxiliary shaft around the main shaft. The plungers of the radial-plunger-type pump or motor are allowed to reciprocally move in identical strokes, and no thrust load is applied between the plungers and the cylinders in which the plungers reciprocally move.

Abstract: A variable-stroke crank mechanism includes a crankshaft rotatably mounted in a casing and having an eccentric crankpin, and a plurality of fluid pressure actuators disposed substantially radially with respect to the crankshaft, for pressing the eccentric crankpin to rotate the main shaft and the casing relatively to each other. The fluid pressure actuators are selectively supplied with a working fluid. An eccentric collar is rotatably mounted on the crankpin and operatively coupled to the fluid pressure actuators. The eccentric collar having an axis which is eccentrically displaced with respect to the axis of the crankpin. The crankpin and the eccentric collar are arrested in their respective angular positions by intermeshing internal and external gears. The crank mechanism may be incorporated in a plunger-type hydraulic unit, which may also be incorporated in a hydromechanical continuously variable transmission.