US 4,901,612 AGranted

Band saw apparatus and method with pressure controlled feed

OwnerGerald R. Harrisinventor

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Abstract

Band saw apparatus is disclosed which includes cutting enhancement apparatus formed for tilting of the cutting stretch of the band saw blade to vary the force per unit area of the cutting edge of the blade on the workpiece. The cutting enhancement apparatus which tilts the blade at both guide assemblies is shown. The saw carriage is movably mounted to the remainder of the saw to be substantially free to rebound or move away from the workpiece during tilting of the blade to avoid digging in or shearing off of the blade teeth and to permit close spacing of the blade guides next to the workpiece. The saw includes a feed control system having both an orifice control circuit and a support force control circuit. A method is disclosed which is comprised of using the support force circuit to vary the rate of cutting during the cut to prevent overloading of the blade and/or stalling of the machine. Sensors feedback signals which adjust the support force circuit to control feeding.

Claims18

Dependent claims

A method of cutting a workpiece with a band saw, said band saw having a movable carriage, a band saw blade mounted to said band saw for advancement to effect cutting, and said fluid control means coupled to control movement of said carriage during cutting of said workpiece, said fluid control means including an adjustable orifice means controlling the flow of a working fluid to control movement of said carriage and an adjustable support force means for providing a support force in a direction opposing and thereby controlling movement of said carriage, said method including the steps of:

prior to cutting said workpiece, adjusting said fluid control means to control movement of said carriage when cutting thin sections of said workpiece and when cutting thick sections of said workpiece, and thereafter cutting said workpiece by advancing said blade and simultaneously moving said carriage as controlled by said fluid control means, wherein the improvement in said method comprises:
said step of adjusting said fluid control means is accomplished by adjusting said orifice means to control movement of said carriage when in said thin sections and by adjusting said support force means independently of said orifice means to control movement of said carriage in said thick sections;
and
during said cutting step, controlling the rate of movement of said carriage means by varying said support force means independently of said orifice means while maintaining said orifice means at least as open as adjusted prior to cutting to substantially prevent excess loading of said blade and said band saw by controlling said loading independently of the resistance of said workpiece to cutting.

1 more element

A method of cutting a workpiece with a band saw, said band saw having a movable carriage, a band saw blade mounted on said carriage for advancement to effect cutting, fluid control means coupled to control movement of said carriage during cutting of said workpiece, said fluid control means including an adjustable orifice means controlling the flow of a working fluid to control movement of said carriage and an adjustable support force means adjustable independently of said orifice means for providing a support force in a direction opposing movement of said carriage, and cutting enhancer means coupled and operable to enhance the cutting rate, said method including the steps of:

prior to cutting said workpiece, adjusting said orifice means to control movement of said carriage when cutting thin sections of said workpiece, prior to cutting said workpiece adjusting said support force means to control movement of said carriage when cutting thick sections of said workpiece, and thereafter cutting said workpiece by advancing said blade and simultaneously moving said carriage as controlled by said fluid control means, wherein the improvement in said method comprises:
during said cutting step, operating said enhancer means, and controlling the rate of movement of said carriage means by adjusting said support force means independently of said orifice means while simultaneously maintaining said orifice means as adjusted prior to cutting.

Band saw apparatus including a movable carriage, wheel means rotatably mounted to said carriage, an endless band saw blade mounted to said wheel means, a pair of relatively spaced-apart blade support assemblies carried by said carriage and engaging said blade at spaced-apart locations along said blade to define a cutting stretch therebetween, and displacement means formed to periodically displace said blade toward and away from said workpiece during cutting movement of said blade, wherein the improvement in said band saw apparatus comprises:

said displacement means being mounted to each of said support assemblies and formed for displacement of a blade engaging portion of each of said support assemblies substantially simultaneously in opposite directions to produce alternating tilting of said cutting stretch relative to said carriage about a center of said tilting located between said support assemblies proximate a plane passing through the center of the cross section of said workpiece to enhance cutting by periodically reducing the area of said workpiece being engaged by said blade and to minimize displacement of said carriage in reaction to said tilting.

Dependencies are inferred from the claim text.

Facts

Application: 07/048,908Filed 12 May 1987 · continuation in part
Priority: 6 Feb 1984
Granted: 20 Feb 1990
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

B23D 59/008
Accessories specially designed for sawing machines or sawing devices: comprising computers
B23D 53/08
Machines or devices for sawing with strap saw-blades which are effectively endless in use, e.g. for contour cutting: for cutting profiled stock
B23D 55/086
Devices for guiding strap saw blades: with means for automatically adjusting the distance between the guides
B23D 55/089
Devices for feeding strap saw blades: with fluid regulating means for in-feed

Family

Serial577,527Parent of this continuation-in-part · filed 6 Feb 1984
Serial609,429Parent of this continuation-in-part · filed 11 May 1986
US 4,766,790 AParent of this continuation-in-part
US 4,558,614 AParent of this continuation-in-part
US 4,901,612 AThis patent

From the US filing history. Foreign family members aren’t listed.