Abstract: A saw for cutting an extruded, prestressed concrete slab having a length, a width and a thickness includes a framework assembly movable along the length of the concrete slab. A carriage system is rotatably supported from the framework assembly about a first vertical axis perpendicular to the concrete slab and is slidably mounted on the framework assembly for movement back and forth across the width of the concrete slab. A cutting arrangement including a rotary cutter is suspended from the carriage system over the concrete slab. The cutting arrangement is movable up and down along a second vertical axis substantially parallel to the first vertical axis and is also slidable along the carriage system.

Abstract: A saw for cutting an extruded, prestressed concrete slab having a length, a width and a thickness includes a framework assembly movable along the length of the concrete slab. A carriage system is rotatably supported from the framework assembly about a first vertical axis perpendicular to the concrete slab and is slidably mounted on the framework assembly for movement back and forth across the width of the concrete slab. A cutting arrangement including a rotary cutter is suspended from the carriage system over the concrete slab. The cutting arrangement is movable up and down along a second vertical axis substantially parallel to the first vertical axis and is also slidable along the carriage system.

Abstract: A hydraulic door operator includes a reversible hydraulic pump driven by an electric motor and connected in a closed loop to a reversible hydraulic motor which operates the door. A bypass valve assembly is connected across the loop between the pump and hydraulic motor. The bypass valve assembly is operative when fluid is delivered by the pump to drive the motor in one direction so that a portion of the fluid flow is bypassed from reaching the motor. When the pump is operated to deliver fluid to drive the motor in the opposite direction, the bypass valve assembly is inoperative. When operative, the bypass assembly will cause the motor to be driven at a slower speed than it will be driven when the bypass valve assembly is inoperative.