US1722316A - Hack saw - Google Patents

Description

July 30, 1929. w, AFFQ D 1,722,316

HACK SAW iled March 16, 1928 INVENTOR.

A TTORNEYS Patented July 3Q, 1929.

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JAMES WEBB SAFFOLD, OF CLEVELAND, OHIO.

HACK SAW.

Application filed March 16, 1928; Serial N'o. 262,083.

The pr sent invention, relating as indicated to hack saws, is more particularly directed to an improved hack sawrhaving a frame permitting of placing a considerable tension on the hack saw blade without distortion of the frame. A further object of the invention is the provision of a simple and extremely rigid two-part frame construct-ion which may conveniently and quickly be adjusted to receive and tension the blades, as well as to disengage the same when desired. A further object of the invention is the provision of simple blade retaining means in opposed parts of the frame, together with beams for mounting the blades in either of two planes at right angles to each other and to mount blades in parallel planes for producing parallel saw slots when desired.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims; the annexed drawing and the following description setting forth in detail certain mechanism embodying the invent-ion, such disclosed means constituting, however, but one of various mechanical forms in which the principle of the invention may be used.

In said annexed drawing Fig. 1 is a side elevation partially in section of the frame contemplated by the present invention; Fig. 2 is a sectional View taken substantially on the line 22 of Fig. 1, and looking in the direction of the arrows; Fig. 8 is an end elevation'of the projection extending from the handle member showing a section of a blade in position thereon; Fig. 4 is a section taken substantially on the line 44: of Fig. 1, and looking in the direction of the arrows; Fig. 5 is a sectional view showing the saw of the present invention in use to cut a slot in a piece of work; Fig. 6 is a similar view showing the saw in. use to make a cut spaced a given distance from the edge of a piece of work; Fig. 7 is a sectional view taken substantially on the line 77 of Fig. 3, and looking in the direction of the arrows; and Fig. 8 is a similar view on line 8-8 of Fig. 4 showing a modification of the saw engaging means.

Numerous attempts have been made to produce hack saws having a two-part telescoping frame for the purpose, of course, of providing a tensioning means for the blades which will be really effective in placing these under a considerable tension. The difliculty which has been experienced in all saws of this type, however, has been when ordinary circular tubing and circular parts have been telescopically engaged the stress placed upon these members when a saw blade is tensioned in the frame has been so severe that the frame is bowed, with resultant rapid wear on engaging parts of the two members, and with the difficulty that after the telescoping parts have thus been strained it has been very diliicult to adjust them with respect to each other. As a result of these difficulties the ordinary standard hack saws which are in use are ordinarily formed with a rigid non-telescoping frame and an adjustment for the saw blade is provided in one of the arms of the frame, which adjustment is ordinarily inadequate to properly tension the blade. The purpose of the present in-. vention is to provide a frame having two telescoping members of extreme rigidity and of such character that the ordinary strains imposed upon these two members at the points of engagement are insufficient to overcome the natural rigidity of the members so that the twoparts of the frame remain in the predetermined and desired relationship to each other, while atthe same time permitting an extremely severe tension to be placed upon the blades, minimizlng the risk of breakage and improving the quality of the work which the saw is capable of performing.

My improved saw consists of two cooperative members 1 and 2 which are telescopically engaged with each other, and which constitute the frame, the members being provided with extensions 3 and 4, respectively, which extend toward each other in the same plane, and between which the saw blade may be mounted. The member 1, which is the handle member of the frame, is provided with a handle 5 and with. a tubular extension 6 therefrom, within which is telescopically received the member 2. These two members are formed to provide a maximum strength and resistance to bending in the plane of the saw, since the stress imposed upon these members when the saw blade is placed under tension tends to bend the two members upwardly and away from the saw blade. Accordingly the member 6, which is of tubular form, has its maximum depth in the plane of the saw, as shown in Fig. 2, being substantially circular with flattened sides in cross section, while the member 2 is similarly formed with its maximum depth in the plane of the saw, and is roughly of I-beam cross-section, the portions 7 and 8 of the member corresponding to the flanges of an I-beam being formed as parts of the same cylinder, and being threaded.

These two members are engaged as indicated in Fig. 1 and are locked in .any desired engagement by means of a hand .nut 9, which abuts against the end of the tubular member 6 and engages over the threaded flanges 7 and 8 of th other member .2. By rotating the nut in one direction or the other the members may be brought closer together or may be spaced apart for the purpose of applying tension to a saw blade held between the aligned extensions 3 and 4.

The extensions are provided with engaging projections in the form of pins 10 and 11, the pins 10 being those lying in the plane of the saw and projecting from the upper and lower faces of the extensions 3 and 4c. The pins 11 are those which project from the lateral faces of the two extensions, and by this arrangement of projections it is possible to engage a saw blade on any of the faces of the extensions so that the saw blade will lie in planes either parallel or at right angles to the plane of the saw, as may be desired.

The pins are engaged in the extensions in the manner shown in Figs. 7 and 8. An opening is provided through the extension into which the pin is driven with a reasonably tight fit, after which the ends are bent over the projection toward the end of the frame, and this angular disposition of the projections serves the double purpose of causing the blade which is engaged thereover to be drawn tightly against the suy porting face of the extension when the plate is tensioned in the frame, and to be forced of]? from the projection when the two parts of the frame are caused to approach each other, thus making it possible to automatically disengage a blade when its removal is desired. 7

In Figs. 3, 4 and 8 I have shown one of the series of pins 15 provided with a threaded and prolonged extension 16, on which are adapted to be received spacing washers 17. These washers are of the same thickness, and their thickness may be ordinary fractional units either of an inch or centimeter, as desired, to provide for the convenient mounting of multiple saw blades for the cutting of spaced parallel slots at given distances apart. The washers, together with the saw blades properly spaced, are then clamped in this relationship by a convenient wing nut 18 in the manner indicated, and the placed sawsmay then be used either for sawing a slot a given distance away from the side 19 of an article (see Fig. 6), in which case the outer saw blade 20 merely serves as a guide for properly positioning the operating saw blade 21, or the two saws 20 and 21 may be used as indicated in Fig. 5 for cutting the parallel slots spaced a predetermined distance apart.

The advantages of my improved construction are, first, its rigidity, and hence its long life; second, the convenience of use and the easy mounting and dismounting of saw blades; third, the extreme tension which may be placed upon the blades; and fourth, the features which permit the use of multiple blades for producing parallel slots having a predetermined spacing.

Other modes of applying the principle of my invention may be employed instead of the one here explained, change being made as regards the mechanism herein disclosed, provide l the means stated by any of the following claims or the equivalent of such stated means be employed.

I therefore particularly point out and dis tinctly claim as my invention 1. A hack-saw comprising a handle member provided with a tubular extension of circular cross-section with flattened sides, an end member provided with an extension of general Lbeam cross-section, the flanges of said I-beam being formed as parts of a cylinder and being threaded, a nut engaging upon said threaded flanges of said end member and abutting against the end of said tubular member, and said members being provided with aligned extensions, each adapted to receive the end of a saw blade.

2. A hack saw frame comprising members adjustable toward and away from each -other, a rectangularly shaped projection on each of said members, said pro ections extending toward each other and in alignment, oppositely inclined pins provided on one side of each said projections, threaded studs on the opposite side of each projection, and a plurality of removable spacing members and an adjusting nut on each of said studs.

Signed by me, this 12th day of March,

JAMES VEBB SAFF OLD.

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