PERCUSSIVE MASSAGE DEVICE WITH SELECTABLE STROKE LENGTH
A percussive massage device includes a cylinder extending along a longitudinal axis. A motor shaft that rotates about a central axis perpendicular to the longitudinal axis. A crank coupled to the shaft includes a first pivot offset from the central axis. A pinion gear is coupled to the first pivot. The pinion gear rotates within a ring gear. The pinion gear has a second pivot that rotates about the first pivot. A reciprocation linkage is coupled between the second pivot and a piston that moves longitudinally within the cylinder. An applicator head coupled to a second end of the piston has an end exposed outside the cylinder for application to a person receiving treatment. An actuator selectively rotates the ring gear to cause the applicator head to have a first stroke length and at least a second stroke length.
1 . A battery-powered percussive massage device, the device comprising:
an enclosure having a cylindrical bore, the cylindrical bore extending along a longitudinal axis;
a piston located within the cylindrical bore, the piston having a first end and a second end, the piston constrained to move only along the longitudinal axis of the cylindrical bore;
a motor positioned within the enclosure, the motor having a rotatable shaft;
a gear case coupled to the motor, the gear case comprising:
a ring gear having internal gear teeth; and
a pinion gear having external gear teeth engaged with the internal gear teeth of the ring gear, the pinion gear adapted to be rotated by the rotatable shaft of the motor;
a reciprocation linkage having a first end and a second end, the first end of the reciprocation linkage coupled to the pinion gear, the second end of the reciprocation linkage coupled to the first end of the piston; and
an applicator head having a first end and a second end, the first end of the applicator head coupled to the second end of the piston, the second end of the applicator head exposed outside the cylindrical bore.
2 . The device of claim 1 , wherein the actuator is manually operated.
3 . A method of operating a percussive massage device comprising:
rotating a shaft of an electric motor;
coupling the electric motor to a pinion gear within a gear casing, the pinion gear having external teeth engaged with internal teeth of a ring gear, the ring gear rotatable by the shaft;
coupling the pinion gear to a first end of an interconnection linkage of a reciprocation assembly;
coupling a second end of the interconnection linkage to a first end of a piston constrained to move along a longitudinal centerline;
coupling a second end of the piston to an applicator head wherein rotational movement of the shaft of the electric motor causes reciprocating longitudinal movement of the piston and the applicator head.
4 . The device of claim 1 , wherein the shaft includes a central axis perpendicular to the longitudinal axis of the cylindrical bore.
5 . The device of claim 1 , further comprising a crank coupled to the shaft.
6 . The device of claim 5 , wherein the crank comprises a pivot offset from the central axis of the cylindrical bore.
7 . The device of claim 6 , wherein pinion gear includes a central bore that receives the pivot of the crank.
8 . The device of claim 7 , wherein the pinion gear includes a pinion gear pivot offset from the central bore.
9 . The device of claim 1 , wherein the ring gear includes a first angular position and a second angular position with respect to the central axis of the shaft.
10 . The device of claim 1 , wherein the first end of the reciprocation linkage directly coupled to the pinion gear.
11 . The device of claim 1 , wherein the gear case includes an actuator coupled to the ring gear.
12 . The device of claim 11 , wherein the actuator is configured to rotate the ring gear.
13 . The device of claim 1 , wherein the applicator head includes a stroke length determined by an angular position of the ring gear.
14 . The method of claim 3 , wherein the rotating the shaft of the electric motor rotates a pivot of a crank about a centerline of the shaft.
15 . The method of claim 3 , wherein the ring gear rotates from a first angular position to a second angular position.
16 . The method of claim 3 , wherein the first end of the interconnection linkage of the reciprocation assembly is directly coupled to the pinion gear.
17 . The method of claim 14 , wherein the rotating the pivot of the crank causes movement of the piston.
18 . The method of claim 3 , wherein the reciprocating longitudinal movement provides a first stroke length when the ring gear is in a first angular position and provides a second stroke length when the ring gear is in a second angular position.
19 . The method of claim 18 , wherein the first angular position and the second angular position are with respect to a central axis of the shaft.
20 . The method of claim 3 , wherein the ring gear is rotated by an actuator.