US690678A - Double-cutting band-saw. - Google Patents

Description

' El E. THOMAS.

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(Application Sled Oct. 12, 1901.)

(No Model.)

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i EDWIN E. THOMAS, OF ST. PAUL, MINNESOTA, ASSIGNOR OFONE-HALF TO.V

UNION IRON WORKS, OF MINNEAPOLIS, MINNESOTA, A CORPORATION UNITED [STATES OF MINNESOTA.

PATENT OEEICE.

DOUBLE-CUTTING BAND-SAW.

SPECIFICATION forming part of Letters` Patent No.`690,678, dated January 7,1902.

Application' filed October 12 1901. Serial No. 78,411. (No model.)

To all whom, t may concern.:

Be it known that LEDWINE. THOMAS, of St. Paul, Ramsey county, Minnesota, have invented certain new and useful Improvements in Double-Cutting Band-Saws, of which the following is a specification.

In the operation of a band-mill it is necessary that the edges of the saw be under'considerable tension to i-nsure good results in sawing, and to produce this tension it is customary to lengthen out the saw along its middle line, so that when placed onthe Wheels its middle portion will be out of contact with them and the strain will be thrown out to the edges, which will sustain the tension of the saw.I This lengthening or expanding of the middle portion of the saw is done by hammering or rolling the metal and is a tedious and laborious task and one lthat requires the services of skilled workmen to insure uniform stretching or expansion.

The object, therefore, of my invention is to provide a double-cutting band-saw of such construction that the operation of expanding its middle portion will be greatly simplified and facilitated.

A further object is to provide a saw that can be more readily fitted to wheels having crowning faces.'

The invention consists generally in providinga band-saw with a series of longitudinal slots arranged at intervals along its middle line.

Further, the invention consists in various constructions and combinations, all as hereinafter described, and particularly pointed out in the claims.

In the accompanying drawings,formin g part of this specification, Figure l is a plan View of a portion of a double-cutting band-saw emg which'connect theopposite edges of the saw.

These slots cause a considerable reduction in the amount of metalalong the center of the saw without materially weakening it and reduce,very largely the area that the workmen have to hammer or roll to properly expand the saw.

Instead of going over the whole middle portion of the saw, as heretofore, it is only necessary to hammer the edges of the slots a little to produce the requisite expansion, and this operation does not require nearly as much care and attention as has been necessary to exercise in expanding the ordinary band-saw.

To adapt the same for use on crown-faced wheels, the bridges are struck a fewy strokes with a hammer to bend them sufficiently to clear the highest point of the crown and cause the weight applied on the wheels to be sustained by the edges of the saw.

'I may provide a single cutting band-saw with longitudinal. slots for the same purpose; but the invention is designed and I regard it as particularly adapted for use with saws of the double-cutting type.

I claim as my invention- Y '1. A band-saw -provided with a series of elongated slots extending lengthwise thereof at intervals.

2. A double cutting band saw provided with a series of comparatively long narrow slots extending lengthwise thereof along its medial line.

EDWIN E. THOMAS.

In presence of RICHARD PAUL, M. C. NooNAN.

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