Hydraulic and electrical circuits for a heavy-duty saw

In a heavy-duty saw assembly having a base, a pair of spaced columns thereon, a saw feed carriage guidably mounted upon the columns upon vertical axes and supporting a power-driven saw rotatable upon a horizontal axis a hydraulic lift feed cylinder assembly within each column and connected to said saw feed carriage, an elongated roller train extending at right angles to said base and connected thereto, including a plurality of spaced transverse rollers, a continuous sprocket chain connected to the rollers for selective rotation in unison for intermittently feeding an elongated workpiece onto said base transversely of and under the saw, spaced normally open rear and front hydraulic vises adjustably mounted upon said base rearwardly and forwardly of the saw respectively adpated to selectively grip the work, and a pair of spaced manually rotatable lead screws journaled upon the base adapted for connection to said vises respectively, the improvement of hydraulic circuit means therefor comprising:

• first and second hydraulic circuits;
• first and second power-operated hydraulic pumps for feeding hydraulic fluid into said circuits respectively;
• a four-way, three-position, spring centered, solenoid-activated saw feed carriage first valve in said first circuit having an outlet connected to the lift feed cylinder assemblies for selectively raising and lowering the saw feed carriage;
• a reversible hydraulic motor having an output drive connected to said sprocket chain;
• a four-way, three-position, spring centered, solenoid-activated second valve in said first hydraulic circuit having an output connected to said hydraulic motor;
• a two-position, four-way, spring offset, solenoid-operated third valve in said second hydraulic circuit having an outlet connected to said rear vise;
• said saw feed carriage being initially retracted, activation of said second four-way valve and hydraulic motor first actuating said rollers;
• activation of said third valve closing said rear vise upon the work;
• and
• successive actuating of said first valve actuating said cylinder assemblies for feeding the saw to and through said work.