Slab grinder, hydraulic counterbalance and lift control

Claim 1

IN A SLAB GRINDER, AN ABRASIVE WHEEL, AN ELECTRIC MOTOR TO ROTATE SAID WHEEL, A HYDRAULIC MOTIVE MEANS COMPRISING A CYLINDER, A PISTON IN SAID CYLINDER, AND A PISTON ROD EXTENDING THROUGH AN END OF SAID CYLINDER FROM SAID PISTON, LINKAGE MEANS INTERCONNECTING SAID WHEEL AND SAID PISTON ROD, SAID WHEEL SUPPORTABLY DEPENDING FROM SAID LINKAGE MEANS, A PUMP, HYDRAULIC FLUID, SAID PUMP MAINTAINING SAID FLUID UNDER PRESSURE IN SAID HYDRAULIC MOTIVE MEANS ACTING ON SAID PISTON AGAINST THE WEIGHT OF SAID WHEEL, A PRESSURE REGULATOR FOR SAID FLUID IN SAID HYDRAULIC MOTIVE MEANS, A CONTROLLER INCLUDED IN SAID PRESSURE REGULATOR TO CONTROL THE PRESSURE OF SAID FLUID IN SAID HYDRAULIC MOTIVE MEANS, ELECTRIC ACTUATION MEANS ASSOCIATED WITH SAID ELECTRIC MOTOR AND SAID CONTROLLER, SAID ELECTRIC ACTUATION MEANS BEING SENSITIVE TO THE AMPERAGE OF SAID MOTOR AND ACTING UPON SAID CONTROLLER CAUSING THE PRESSURE OF SAID FLUID TO BE INCREASED TO REDUCE THE DOWNWARD FORCE OF SAID WHEEL ON A SLAB AND THE AMPERAGE REQUIREMENT OF SAID ELECTRIC MOTOR WHEN SAID AMPERAGE INCREASES OVER A PREDETERMINED AMOUNT AND TO BE DECREASED WITH THE OPPOSITE EFFECT WHEN