Sawing method and machine

Claim 2

In a method for sawing a workpiece by means of a cutting tool carried by a support which is movable with respect to a frame and subjected to the action of a double-acting hydraulic cylinder device having a piston defining a working chambEr at one end of the cylinder device and a second chamber at another end of the cylinder device, the cylinder device being interposed between the support and the frame; the improvement that said method comprises feeding the cutting tool into the workpiece to be sawn, during the sawing operation and through the medium of the support, by the effect of a constant pressure of a liquid in the working chamber of the cylinder device so that the force exerted on the support by said pressure is a multiple of the maximum value of the resisting force which opposes the feed of the tool during cutting, said multiple being such that variations in said resisting force during cutting are negligible relative to said force exerted by said pressure, and causing the liquid contained in the second chamber of the cylinder device to flow in accordance with a constant rate of flow so that the rate of feed of the cutting tool into the workpiece is substantially constant irrespective of variations in said resisting force.

Claim 3

A method as claimed in claim 1, wherein the force exerted by said pressure is substantially ten times higher than said maximum value of said resisting force.

Claim 4

In a sawing machine comprising means defining a frame, a support movably mounted on the frame, a cutting tool carried by the support, a double-acting hydraulic cylinder device having a cylinder and a piston slidable in the cylinder and defining at a first end of the cylinder a first chamber and at another end of the cylinder a second chamber, the cylinder device being interposed between the frame and the support for shifting the support in a direction to feed the cutting tool into the workpiece, liquid supply means connected to said chambers and arranged to supply liquid selectively to the first chamber for shifting the support in a direction for feeding the tool into the workpiece and to the second chamber for shifting the support in a direction for returning the cutting tool to an inoperative position; the provision of the following structure: means for putting said liquid under such constant pressure that the pressure in said first chamber exerts a force on said support in the course of cutting which is a multiple of the maximum value of the resisting force which said tool encounters as it is fed into said workpiece during cutting, said multiple being such that variations in said resisting force during cutting are negligible relative to said force exerted by said pressure in said first chamber, a flow regulator communicating with said second chamber, the flow regulator comprising a manually regulatable throttle for ensuring a constant flow of the liquid discharged from said second chamber and a check valve which by-passes the throttle and is so arranged that the liquid flows freely through the check valve in the opposite direction during the inoperative return travel of the cutting tool to said inoperative position.

Claim 5

In a sawing machine comprising means defining a frame, a support movably mounted on the frame, a cutting tool carried by the support, a double-acting hydraulic cylinder device having a cylinder and a piston slidable in the cylinder and defining at a first end of the cylinder a first chamber and at another end of the cylinder a second chamber, the cylinder device being interposed between the frame and the support for shifting the support in a direction to feed the cutting tool into the workpiece, liquid supply means connected to said chambers and arranged to supply liquid selectively to the first chamber for shifting the support in a direction for feeding the tool into the workpiece and to the second chamber for shifting the support in a direction for returning the cutting tool to an inoperative position; the provision of the following structure: means for putting said liquid under such constant pressure that the pressure in said first chamber exerts a force on said support in the course of cutting which is a multiple of the maximum value of the resisting force which said tool encounters as it is fed into said workpiece during cutting, said multiple being such that variations in said resisting force during cutting are negligible relative to said force exerted by said pressure in said first chamber, a flow regulator communicating with said second chamber, the flow regulator comprising a manually regulatable throttle for ensuring a constant flow of the liquid discharged from said second chamber and a check valve which by-passes the throttle and is so arranged that the liquid flows freely through the check valve in the opposite direction during the inoperative return travel of the cutting tool to said inoperative position.