The piston motor operates in reverse of the radial-piston pump. In the radial-piston pump, as the cylinder block rotates, the pistons press against the rotor and are forced in and out of the cylinders, thereby receiving fluid and pushing it out into the system. In the radial motor, fluid is forced into the cylinders and drives the pistons outward. The pistons pushing against the rotor cause the cylinder block to rotate.A piston motor device having a piston rod actuating mechanism mounted in a two-piece housing assembled with a snap fit and having a linkage assembly connected to the outer end of the piston rod for moving a shaft member clockwise and counterclockwise about its axis in response to linear movement of the piston rod. T is, therefore, an object of the present piston motor to construct a piston motor device from a simple and economical manner without requiring skilled labor. Another object of the present piston motor is to construct the housing of a motor piston device from two molded plastic sections having a snap fit connection. It is another object of this piston motor to provide a motor piston device with a linkage assembly for converting piston rod reciprocation to a shaft oscillation. A further object of the present piston motor is to provide the linkage assembly between an oscillatory shaft and a reciprocating rod with an adjustment to control the angular degree of shaft oscillation. The present piston motor is summarized in a motor piston device having a casing of first and second sections with a diaphragm peripherally mounted there between, a spring means in the casing for applying a biasing force to the diaphragm, a pressure chamber in the casing for applying a pressure force of the diaphragm in opposition to the biasing force, a piston disposed between the spring and the diaphragm and having a piston rod extending out of the casing for connection to a linkage assembly, and a mating interlocking connection between the two sections of the casing permitting the assembly with a snap fit.
Piston motors are available in two basic types- crankshaft type (e.G. Staffa or sai motors) with a single cam and pistons pushing inwards. This type of motor is basically an old design but is one which has extremely high starting torque characteristics. They are available in displacements from 40cc/rev up to about 12 liters/rev but can sometimes be limited in power output. Crankshaft type piston motors are capable of running at "creep" speeds and some can run seamlessly up to 1500 rpm whilst offering virtually constant output torque chacteristics. This makes them still the most versatile design. Multilobe cam ring type (e.G. Hagglunds or poclain type) has a cam ring with multiple lobes and the piston rollers push outwardly against the cam ring. This produces a very smooth output with high starting torque but they are often limited in the upper speed range.
