Stroke adjustment for reciprocating mechanism

In a stroke adjustment for reciprocating mechanisms of the type including a crank, a piston reciprocated by the crank and a power shaft supplying rotary power, the combination of

• an arm connected to the power shaft in a pivotal power shaft connection and being adapted to be rotated by the power shaft,
• said arm comprising an adjustable connector to which one end of the crank is connected and a projecting pin positioned in spaced relationship from the pivotal power shaft connection;
• a collar axially movable along the power shaft, said collar including slot means slidingly engageable by the projecting pin, the engagement of the projecting pin within the slot means causing rotation of the arm about its pivotal power shaft connection as the collar is axially moved;
• and
• an adjustment means adjacent to the collar to axially move the collar relative to the power shaft,
• the adjustment means comprising an external handle, an adjusting shaft adapted to be rotated by the handle and gear means interposed between the adjusting shaft and the collar to axially move the collar along the power shaft in response to rotation of the handle, and
• the adjustment means further comprising threaded means interposed between the gear means and the collar to axially move the collar along the power shaft in response to rotation of the handle;
• whereby movement of the collar in a first axial direction causes the engaged pin to pull the arm in a clockwise direction about its pivotal power shaft connection to raise the adjustable connector and thus vary the eccentricity of the crank, and
• whereby movement of the collar in the opposite axial direction causes the engaged pin to push the arm in a counterclockwise direction about its pivotal power shaft connection to lower the adjustable connector and thus vary the eccentricity of the crank.