US565390A - Chester prouty - Google Patents

Description

2 Sheets-Sheet l. C. PROUVIY.v

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ZU/vesss' 2 Sheets-Sheet 2. G. PROUTY.

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SAW.

Patented Aug. 418-96.

Witnesses:

Attorneys me Nnnms Pneus co, moro-LITRO.. wAsHmGToN. p.c.

UNITED STATES PATENT FFICE.

CHESIR PROUTY, OF DUBOIS, PENNSYLVANIA.

SAW.

SPECIFICATION forming part of Letters Patent No. 565,390, dated August 4, 1896.

Application filed February l2, 1894:. Serial No. 499,951. (No model.)

T0 all whom/ t may concern.'

Beit known that I, CHESTER PROUTY, a citizen of the United States, residing at Dubois, in the county of Oleareld and State of Pennsylvania, have invented certain new and useful Improvements in Saws; and I do hereby declare the following to be a full, clear, and exact description of the'invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My present invention relates to improvements in saws, the improvements being applicable to the largest kinds to do the heaviest and coarsest kinds of work, as Well as to the smallest and nest crosscut-saws suitable for the finest kinds of work.

I have discovered that the central part of a crosscut-saw will wear one-third faster both endwise and transversely than it wears at the ends of the saw-blade, and I propose to so grind the saw-blade as to overcome this objection and produce a sawblade which will hold its set as long in the center as at the ends, which will wear in gage instead of out of gage, or, in other words, the gage will wear uniformly as the saw-blade wears out and narrower, and which will be stiifer at the ends of the blade than other saws heretofore produced, in order that the saw-blade can run true and straightin the kerf when manipula ted by inexperienced sawyers, and also allow the sawyers to push on the saw as well as pull without kinking the saw-blade when it is in use.

WVith these and such other ends in View as pertain to my invention it consists in the novel construction of the crosscut-saw, as will be hereinafter fully described, and pointed out in the claims.

To enable others to understand my invention, I have illustrated the same in the accompanying drawings, forming a part of this speciiication, and in which Figure l represents a full-length side view of a straight-back saw embodying my invention, indicating by diagrammatic lines and iigures the relative thickness or gage of the blade at different points in its length and width. Figs. 2, 3, and 4 are transverse sections taken, respectively, on the lines 2 2, 3 3, and 4L L of Fig. l. Fig. 5 is a side View of a hollow-back saw embodying myL invention;

Fig. 6 is a cross-sectional view similar to Fig. 2 on the line 2 2, Fig. l, but on larger scale than Fig. 2 to more clearly show the different gages. Figs. 7, 8, 9, l0, and 11 are side elevations of saw-blades ground in accordance with my invention, each figure illus tratin g by diagrammatic lines and figures the relative thicknesses or gage of the blade at the different points along its length and width. Fig. 12 is a longitudinal sectional view through the saw near the back edge on the plane indicated by the dotted line ce :r of Fig. l. Fig. 13 is a longitudinal sectional view through the teeth of the saw, the plane of the section being indicated by the dotted line yy of Fig. 5. Like letters of reference denote like parts in all the figures of the drawings.

I will first proceed to describe the construction of the saw-blade and its teeth, also the method of grinding the blade, reference being had more particularly to Figs. l to ll, inelusive.

In the manufacture of saws the gages used in measuring or gaging the thickness of the blades run inversely to the numbers of gages used in measuring ordinary steel or iron plates, that is to say, in saw-gages ascending numbers indicate diminishing thickness, while in ordinary plate-gages ascending numbers indicate increasing thickness. This eX- planation is made to avoid confusion and to give a clear understanding of the signiiication of the numbers used on the drawings.

Referring to the drawings,A designates the blade of the saw. I irst roll the plate to the desired size from suitable steel, and then cut the steel to the desired shape for a saw, after which the ends of the blade are cut with the small projections a ct on the bottom edge, and the two holes b b are then' punched through the blade, near the ends thereof. I then cut out the teeth from the lower edge of the sawblade by means of dies which are made the shape of the perforations and spaces between the teeth, and at the same operation these dies cut out of the saw-blade oblong pieces of metalV which produce in the blade the slots or openings forming the bars or bridges between the saw-teeth, said perforations and the bases of the teeth being concentric with the curved front edge of the saw from end to endthereof. After the saw has been thus IOO the ends.

fashioned I proceed to grind the same in the manner indicated by Figs. 1, 5, and 7 to 11, inclusive.

The saw-blade shown by Fig. l is ground with a taper from its curved cutting edge to the back edge thereof, said taper running from end to end of the saw-blade and increasing toward the center of said blade, thereby producing a greater taper in the center than at the ends, which is due to the fact that the saw is thicker on its cutting edge, in its eentral portion, than at the ends of the blade. In. other words, the saw is ground Wi th a bevel on both faces of the blade which extends longitudinally in curved lines from end to end of said saw-blade. As before stated, the cutting edge of the blade is thicker at the center than at the ends, the relative thicknesses at the different points being indicated in Fig. 1 by the gage-numbers 14, 145-, `and 15, and in Fig. -the numbers 13, 13%, and 14, the ascendin g numbers indicating gradually-diminishing thicknesses from the center toward In Fig. 1 the thickness of the sawblade` at its back edge is indicated by the gage- numbers 20, 19,18, and 17, the descending numbers indicating gradually-increasing thicknesses from the center of the blade toward the ends thereof.

All crosscut-saws are more or less rounded on the cutting edge to cause the center to project forward beyond the en ds of the blade, thus making the center of straight-back saws, such as illustrated by Fig. 1, considerably wider at the center than at the ends, and even hollow-back saws, such as illustrated in Fig. 5, usually taper more or less in width from the center outward, so that under the former system of grinding wlere the front andibaek of the blade are each of uniform gage throughout (thinner at the back than at the front) the taper gradually increases from the center toward the ends, giving the ends of the blade greater freedom and greater liability to lateral play in the saw-kerf than that possessed by the central part of the saw-blade, which results, first, in causing the saw to run harder at the center than at the ends, and, second, in a liability of the ends to run sidewise or out of line with the center, especially in the hands of inexperienced sawyers.

In grinding my saws I give the blade a uniform bevel from front to-back, resulting, by reason of the greater width at the center of the blade, in grinding down the center of the back thinner than the ends, as indicated by the gage- numbers 20, 19, 18, and 17 in Fig. 1,

the lower numbers from the center toward the i thickness of the cutting edge.

By givin g the blade a uniform bevel throughout its length the sides or faces of the blade sustain at all points the same angular relation to the sides or walls of the kerf, whereby the saw is caused to run smoothly and evenly and avoids the liability, before referred to, of the ends of the blade to twist or run out of line with the center of the blade and the line of the kerf.

Obviously the center teeth perform more work than those at or near the ends of the blade, and said central teeth are consequently subjected to correspondingly greater wear and strain, causing them, under ordinary circumstances, to lose their set more rapidly, and especially is this the case when they become worn down in thickness. As soon therefore as the central teeth begin to lose their set the end teeth have a tendency to bind in the kerf and reeut the timber', thereby causing the saw to run hard and to make a ragged or uneven cut. These difficulties I avoid by make the cutting edge thicker at the center than at the ends, thus giving to the teeth subjected to the greatest strain and wear correspondingly greater strength and durability to withstand and resist the same, for as the teeth at the center wear down in thickness they become weak and less able to retain their set, but by my improvement, which consists in making them thicker and stronger at the time the saw is manufactured, the central teeth are able to retain their strength as compared with the end teeth, and hence as they wear down in thickness they gradually wear into gage with the end teeth, instead of wearing out of gage, as heretofore, thus increasing the durability of the saw and requiring less frequent setting.

In Figs. 2 and 6 I have shown the gage-indication 1li-- applied to the edge of the cutter-teeth, and in Fig. 3 the gage lei-i is likewise applied to the edge of another `cuttertooth. It should be understood that the gageindication shown as examples of the different thicknesses applies to the gage of the saw cutter-teeth after the blade is ground, as contemplated by my invention, and before the cutter-teeth are subsequently beveled and pointed in the process of finishing the same.

Inexperienced sawyers unaccustonied to the setting of saw-teeth often prefer saws which require no setting, and to meet such demands it is my purpose to provide a saw such as shown in Figs. 7 and 8. In this construction, as in the others shown by Figs. 1 and 5, the cutting edge is thicker at the center than toward-the ends, but the taper is more gradual,as indicated by the gage-numbers 13, 1371-, and 14. The teeth are uniformly beveled from the extreme points to` the-bases thereof, with a bevel approximating one gage-num- Thus in Figs. 2, 3, 4, and 6 the tooth is ber.

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shown as increasing vertically in gage (or de- The sides or faces of the saw-teeth are coni caved or hollow ground from their points to the bases, as shown by Figs. 2, 3, 4, and 6, and each tooth gradually decreases in thickness (or increases in gage) from the point toward the blade proper until the teeth reach a line of uniform gage, say 16, (indicated in Fig. 1 of the drawings,) which line of uniform gage runs throughout the length of the sawblade back of the base-line of the teeth. This style of grinding is especially adapted to saws which are designed to cut checked timber, the concavity of the sides of the teeth giving a quick recession to avoid theA binding action of the checked portion after they have been sawed through.

The method of grinding shown by Figs. 1 to 6, inclusive, produces a saw with its teeth concaved on both sides from end to end of the blade and with the central portion of the blade provided with a bevel extending from the concaved teeth to a point on the curved lines near the back. From the curved lines indicating the lines of grinding of the blade to the extreme back edge the blade is convexed, (see Figs. 2 and 6,) making a crosscutsaw with the greatest decreasing bevel on its teeth and extending throughout the entire length of the blade, a gradually-decreasing bevel extending from end to end of the saw and from the base of the teeth to the lines of grinding near the back of the blade. The blade has a uniform taper on both sides thereof from the base of the teeth toward the first curve line near the thin back edge of the saw, thereby producing an oval or convexed bevel on both faces of the blade.

The method of grinding saws herein described produces a blade which on its cutting edge is thicker at the middle and thinner at the ends, and which blade on its back edge is thinner at the middle than at the ends; or, in other words, the saw-blade is ground with two reversed bevels extending longitudinally from the center to the ends of the blade.

It is to be understood that the gage-numbers on the drawings are used merely for the purposes of illustration and explanation, and, furthermore, that both the thickness and bevel of the saw may be varied at will, as indicated in Figs. 9, 10, and 11, without departing from the spirit of my invention.

The cutting edge of the saw-blade is provided with the cutter-teeth C and with the raker-teeth D. The blade is also provided with the slots E E', (shown by Fig. 1,) which slots serve to facilitate the gumming of sawteeth. These gumming-slots andthe cutterteeth are arranged, preferably, in the manner shown and described in a divisional application iiled by me on the 10th day of May, 1895, Serial No. 548,857.

No claim is herein made to the mode of gumming the saw, the disposition of the raker and cutter teeth in groups, the blade having the expanded ends with the lugs thereof and the reversible handle applied to the expanded end and lug of the blade, because such features are embraced in a separate divisional application led by me on the 10th day of May, 1895, Serial No. 548,857.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. A crosscut-saw which, on its cutting edge, is of lower gage or increased thickness at the middle than at the ends thereof, and which, on its back edge on or within a line drawn between the two end edges, is of greater gage or less thickness at the middle than at the ends, substantially as and for the purposes described.

2. A crosscut-saw blade, which, on its back edge and within a straight line drawn between the ends thereof, is of increased gage or less thickness at the middle thereof than at the ends and having teeth on its cutting edge which are of lower gage or increased thickness at the middle of the saw than at the ends, the sides or faces of all the cutter and raker teeth being concaved from their points to their bases and the cutter-teeth having the beveled and pointed extremities, substantially as and for the purposes described.

` 3. A crosscutsaw having on its convex front edge a series of raker and cutter teeth which are of lower gage or increased thickness at the center of the saw than at the ends and with the back edge of the blade of increased gage or less thickness at the center than at the ends, substantially as and for the purposes described.

4. A crosscut-saw having its cutting edge of lower gage or increased thickness at the middle than at the ends thereof, its back edge on or within a line drawn between the ends of the blade of increased gage or less thickness at the middle thereof than at the ends, and its sides or faces beveled transversely from aline back of the base of the teeth toward the back edge, such transverse bevels extending throughout the length of the blade, substantially as and for the purposes described. K

5. A crosscut-saw having, on its convex cutting edge, the teeth which gradually diminish in thickness or increase in gage from the middle of the blade toward the ends thereof, each tooth having its sides or faces hollowground and the cutter-teeth also having the beveled and pointed extremities, substantially as and for the purposes described.

6. A crosscut-saw having a line of uniform -gage extending, longitudinally, back of the IOO IIO

o1` of increased gage at the middle than at the ends, and on its convex cutting edge a series of teeth which gradually increase in gage or decrease in thickness from the lniddle of the saw toward the ends, each tooth being of increased gage or decreased thickness froln its point to the line of uniform gage `base-line ofl the teeth, its back edge thinner of the saw-blade, substantially as and for the purposes described. 1o

In testimony Whereof- I affix. my sgnatl'lre in presence of tWo Witnesses.

CHESTER PROUTY. 1Witnesses:

G. M. ALcoRN, M. J. SLoiPrY.

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