Hydraulic stroke control for radial arm saws

A device for continuously adjusting the restraining force exerted on a moving element in a first direction and a second direction opposite to said first direction, said device comprising:

• a cylinder having a reciprocating piston mounted therein, said piston having a piston rod having a portion thereof projecting outside an end of said cylinder;
• said cylinder having a first port located at one end portion of said cylinder, and a second port located at the other end portion of said cylinder;
• a first fluid connection line having a first end connected to said first port, and a second end remote from said first end;
• a second fluid connection line having a first end connected to said second port, and a second end remote from said first end;
• valve means interposed between said second ends of said first and said second connection lines, said second end of said first connection line being fluidly connected to one port of said valve means, and said second end of said second connection line being fludly connected to another port of said valve means, said valve means controlling the flow between said ports and, thus, the flow between said second ends of said connection lines as the fluid flows directly from one of said second ends to the other of said second ends;
• a power hand saw having a motor and a rotary saw blade powered by said motor;
• connecting means having one end thereof connected to said power hand saw, and another end thereof connected to the movable portion of the piston-cylinder arrangement for movement therewith;
• whereby the speed of the cutting stroke of said power hand saw is controlled by adjusting the restraining force of said device by said valve means which restraining force opposes the movement of said power hand saw in at least one of its directions of movement.

A method of continuously adjusting a restraining force exerted on a translating element so that the restraining force may be adjusted to desired settings as the element translates along its path of movement, said method comprising:

• (a) moving the element along a path to perform a desired function;
• (b) restraining the movement of the element during such movement along the path by providing a counterforce, said step of restraining comprising continuously adjusting the counter-force exerted on the moving element to oppose movement thereof;
• (c) returning the translating element in a direction towards its original starting position;
• (d) exerting a counter-force on the translating element during said step (c);
• (e) controlling the counter-force exerted on the translating element during its return movement of said step (c) so that such return counter-force is controlled to determine the speed and ease of return of the translating element, said step of controlling comprising continuously controlling the counter-force during the return of the element.