Abstract: A log carriage system including a pair of carriages (10, 12) mounted for linear movement along a conveyor track. A pair of linear hydraulic motors (32, 44) each include a piston rod (30, 42) for both clamping and linear transfer of a log. A reversible hydraulic pump (62) transfers oil between working chambers (40, 52) of motors (32, 44) to move the log along a linear path past a cutting station. A three-way, two-position valve (120) connects line (68) to tank (T), and disconnects line (70) from system pump (SP), when pump (62) is operated to move oil from motor (32) to motor (44). Alternatively, linear hydraulic motors (32, 44) can be replaced by rotary hydraulic motors and a cable drive system for both clamping the log and moving the log along the linear path.

Abstract: Mechanically programmable hydraulic linear positioner providing a primemover with the ability to assume and maintain accurately any of an arbitrary number of preselected programmed positions, and to quickly reposition the load from one such preselected detent position to another detent position upon command. A Hall effect magnetic field sensor detects load position and generates command signals directly controlling a proportional hydraulic valve. Rotary and manual positioning applications are described.