US2435964A - Pulpwood saw frame - Google Patents

Description

Feb. 17, 1948. w. H. GRAFF PULPWOOD SAW FRAME Filed April 14, 1943 Patented Feb. 17, 1948 PULPWOOD SAW FRAME William Hastings Graff, Philadelphia, Pa., as,-

sgnor to Henry Disston & Sons, Philadelphia, Pa., a corporation of Pennsylvania Application April 14, 1943, Serial No. 483,011

1 claims. (o1. 145-33) l This invention relates to improvements in saw frames and more particularly in frames for pulpwood saws.

A principal object of the invention is to provide a simple and durable device for facilitating insertion and subsequent tensioning of the saw blade in the frame, and for releasably retaining the tensionedblade in the frame.

To this end, the invention contemplates provision in the frame, as a permanent part of the latter, of a novel and improved form of blade-retaining and tensioning device.

Another object of the invention is to provide a blade-retaining and tensioning device of the stated character which shall be substantially tamper-proof.

In the attached drawings,

Fig. 1 is a side view of a frame made in accordance with my invention;

Figs. 2, 3, 4 :md5 are, respectively, views in perspective of elements of the blade-tensioning and retaining device;

Fig. 6 is a view illustrating a preferred method of manufacturing the handle element illustrated in Fig. 2; Y

Fig. '7 is an enlarged sectional view on the line 1'-1, Fig. 1;

Fig. 8 is an enlarged sectional view on the line 8 8, Fig; 1, and Y Fig. 9 is a fragmentary elevational view from the inside oi the frame of the extremity of the frame appearing at the right in Fig. l.

With reference to the drawings, the body of the frame, designated by the reference numeral I, may be made of steel tubing and may have the typical U-shape, as illustrated in Fig. 1. At one end, the frame is formed with a suitable socket designated generally by the reference numeral 2 for reception of one end of the saw blade. In the present instance, the blade is provided at the ends with transversally projecting pins 3, and the pins at the one end are received in slots 4 in the end of the frame which constitute elements of the'said socket. The end of the frame is slotted longitudinally on the inside for reception of the blade, as shown in Fig. 8 at 5, and the metal of the frame at each side of the slot is flattened so that the slots 4-4 are formed in part in the flat contiguous Walls 6 of the slot, and in part in the rounded portion 'I. This permits the blade to be slid inwardly into the slot 5 with the pins in the relatively wide rounded portion 'I and also permits the pins to enter the slots 4-4 through the more widely separated inner ends thereof which lie in the said rounded portions of the frame'.

,other left handed, see Fig. '1.

21 frame. The construction-,provides a simple and .positive means for retaining the one end of the saw blade and avoids the'necessity for non-integral blade-retaining` mean-s at that end of the Pivotallysecured at the opposite end of the frame is a blade-tensioning and retaining device designated generally by the reference numeral II. This device consists of the elements illustrated in Figs. 2 to 5 inclusive, there being a single han- 4die element, shown in Fig', 2, and two each of the .elements shown in Figs. 3, 4 and 5.

As best shown in Fig. 1, this end of the frame I is flattened and bifurcated so as to provide a passage between the branches of bifurcation for the saw blade. To the outer face of each of the iiat branches I2 and I3 is secured, preferably by welding, one of the washers I4 shown invFig. 5. As illustrated, each of these washers is apertured at I5 for reception of a pintle pin IB, see Fig. 4, and one end of the aperture I5, namely that end which adjoins the surface of the associated branch I2 or I3, is countersunk, as illustrated at I1, for reception of a correspondingly formed flange I8 of the pin I6. 'The pin is inserted in the washer before the latter is secured to the frame so that the ange I8 is confined between the washer and the associated branch of the frame, and pins are thereby secured in the frame for a purpose hereinafter described. With refierence to Fig. 7, it is to be noted that the inner end of each of the pins is provided with a cylindrical projection I 9 which enters an aperture in the associated frame branch, this constituting a means for locating the pins I6 in axially aligned positions in the frame. To this end, the apertures 2| are formed in accurate alignment with each other.

Each of the pins I6 is adapted to receive one of the blade retaining elements 22, illustrated in Fig. 3, of which one is right handed and the Each of the elements 22 is provided with an aperture 23 countersunk on. the outer face of the element as illustrated at 24. After the elements are inserted on the pins in relative positions illustrated in Fig. 7, the ends of the pins are riveted over into the countersinks 24 so as to secure the elements 22 on and preferably to the pins. After application of the elements 22 to the pins in this manner, the handle element 25, shown in Figl 2, is placed in position with the terminal branches 26-26,

against the outer faces of the respective elementsl 22 and overlying the outer riveted ends of the pins I6, and are secured, preferably by welding,

in this position to the said elements; or the relative positions of the handle element 25 and bladeretaining element 22 are best shown in Figs. 1 and 7, it being noted that the handle extends substantially at right angles to the longitudinal center lines of the elements 22.

Each of the elements 22 comprises an inset end portion 21 and in each of these end portions is a slotted recess 28. The recesses 28 are adapted to receive the pins 3 at the end of the saw blade whereby when the handle 25 occupies the position shown in Fig. 1, in which it bears against the outer side of the end of the frame, the saw blade is locked in tensioned position within the frame. It is to be noted that the handle 425 Ina-y be readily produced from sheet metal from a flat blank of the general form illustrated in Fig. 6v; and that each of the elements I4 and 22 are similarly adapted to be produced from sheet metal.

With the two elements 22 secured respectively to the branches 26 of the handle element 25, these three elements form in effectan integral bell crank 'lever which is bifurcated-as to the one ann which comprises the elements 22 and as to the adjoining portion of the other arm consisting el. the handle element. The branches of this `bifurcated lever are pivotally secured, respectively, to the branches I2 and I3 of the bifurcated end-.of the frame. This preserves a passage for the saw blade between the several branches and is productive of an entirely symmetrical structure in which the strains are nicely balanced between `the pivot pins lI 6,

Itis to be noted also 'that by securing the pivot pin I6 to the elements 22, as `previously described, the said pins will `rotate with the aforesaid bell crank lever and with respect to the branches I2 .and I3 oi the frame and the washers I4 which are secured to said branches. The pins thereby `find a bearing not only-in the washers It but also in the said branches I2 and I3 by reason of the projection I9 of the pins which occupy the apertures 2l of the branches. This extended bearing makes for strength and durability.

In inserting a, saw blade in the frame, the

handle element 25 is drawn away from 'the frame, as indicated in broken lines in Fig'. 1, and through an angle of approximately 180 or until the retaining elements 22 are brought to the inside of the frame. The pins 3 at one end of the saw `blade are then inserted in theA socket 2 and the pins at the opposite end in the now inverted recesses 28. The handle element 25 is then turned to the operative position shown in full lines in Fig. l, the blade being therebyv placed under strong tension in the resilient metal frame. In this latter movement, the blade is'carried between the frame branches I2 and I3, and in order to facilitate entrance of the blade the inner edges of the said branches are beveled, as indicated at -29 in Fig. Si, these bevels acting as guides and precluding snagging of the blade on either side of the slot entrance. -When the arms 22 are in the operative position shown in Fig; l, the line inter secting the pins 3 `blade is above the axis of the pivot pins I6 so that the tension operates to retain the blade-tensioning and retaining device in the operative position. The blade may be released from the frame by a simple reversal of the steps V'previously described. f

It is to be noted that in this device, the working elements of the blade-tensioning and retaining device, are, in effect, housed within the hollow interior of the bifurcated end ofthe handle 25 at the opposite ends of the and are therefore concealed and not accessible for tampering. The parts being Welded as described, the entire device becomes in effect a permanent part of the frame but so that there is no possibility of any of the elements of the device becoming loose from the frame and being lost or mislaid. The device, while simple .in form, is highlyfdura'ble and the encas'ement of the working elements of the device within the hollow handle, as described above, precludes damage to these parts in the rough handling to which saws of this type are frequently subjected.

I claim:

1 A sawfframe'o'f the type set forth, said frame having 'flat `relatively spaced portions at one end defining the sides of a narrow slot extending longitudinally from the extremity of the frame in the plane of the latter, a washer secured to the outer vface of each of said flats, a pin having a head portion conned between each of said washers and the associated ilat portion of the frame and projecting outwardly through an aperture in the washer, said pins being aligned and 'defining a pivotal axis at right angles to the plane of the slot, a bifurcated lever havingits branches over lying the outer ends of the pins, a washer secured to the outer end of Veach o'f said pins and secured respectively to the inner faces of said lever branches whereby the said lever is attached to the pins, blade-retaining 'means in the 4said lever branches eccentrically positioned with respect to said pivotal axis, and means for adjusting the lever about said axis. l

2. A saw frame of the type set forth, said frame having flat relatively spaced portions at one end dening the sides of a narrow slot extending longitudinally from the extremityof theframe in the plane of the latter, aligned pins projecting respectively from the outer faces of said' flats and defining a pivotal axis at right angles to the plane of the slot, a bifurcated lever having its branches overlying the outer ends of said pins, means on the inner faces of said branches for attaching the lever to the pins,v vblade-retaining means in the said branches eccentrically positioned with respect to said pivotal axis and means for adjusting the lever on the frame about said axis.

3. A saw frame of the type set forth, said frame having flat relatively spaced portions at one end defining the sides of a narrow slot extending longitudinally from the extremity of the frame in the plane of the latter, a pair of pins projecting respectively from the outer faces of said flats and having their inner ends 'insertedl in aligned aperltures in said ats, a washer having an aperture for passage of said pin and secured 'to theoute'r face of each of said flats, each of said pins having a head portion confined between a washer and the outer face of the associated flat, a pair of arms permanently attached to the outer ends of the pins respectively, and a biurcated arm having vits branches overlying and secured against the outer faces of the said arms and forming with the latter a bell crank lever adjustable on the frame about the common axis of said pins, and blade-retaining means in the first named arms eccentrically positioned with respect to said pivotal axis.

4. A saw frame of the type set forth, said frame having fiat relatively spaced portions at one end defining the sides of a narrow slot extending longitudinally from the extremity of the frame in the plane of the latter, a pin projecting'from the 'outer face of each of said flats and having its inner end rotatably inserted in an aperture in the associated flat, said apertures being aligned and said pins dening a. common pivotal axis at right angles to the slot, a washer secured to the outer face of each of said iiats and having an aperture therein for passage of the pin, said pins having head portions loosely confined between the associated washer and the frame, a bifurcated lever having its branches rigidly secured respectively to the outer ends of the pins, blade-retaining means in said branches eccentrically posisitioned with respect to said pivotal axis, and means for adjusting the lever about said axis.

5. A metal saw frame having a flat bifurcated end portion, said bifurcations having aligned apertures, a pintle pin having a cylindrical end portion journaled in each of said apertures and having also an adjoining collar engaging the outer face of the bifurcation, a washer secured to the said outer face of each of the bifurcations and having a journal aperture for reception of the pin and a countersunk recess at one end of said aperture for reception of the said collar, said pins being thereby rotatably secured in axially aligned relation in the said bifurcations, and blade-retaining means pivotally mounted on the outwardly projecting ends of said pins.

6. A saw frame having a bifurcated end portion, a blade-retaining member having bifurcations adjacent to the bifurcations of the frame. 3o

and aligned pintle pins entirely confined by and between the said bifurcations and permanently pivotally connecting the bifurcations of the retaining member with the bifurcations of the frame respectively.

7. A tubular metal saw frame of generally U- shape, the wall at one end of the frame being slit at the inside and being unbroken at the outside of the U and being in part flattened in an area. immediately adjoining said slit so as to provide a iiat sided blade-receiving slot entering from the inside of the U and terminating in an unbroken tubular portion, and an elongated slot in each side of the wall for reception of blade-retaining elements, each of the slots lying in part within the said tubular and in part within the adjoining iiat portion of the wall.

WILLIAM HASTINGS GRAFF.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS

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