US1590175A - Undercutter - Google Patents

Description

June 22 F. 5. SMITH UNDERCUTTER Filed May 14, 1925 Patented June 22, 1926.

UNITED STATES PATENT orrice.

UNDERCUTTER.

Application filed May 14, N25. Serial No. 30,215.

This invention relates to undercutters, used in sawing cuts in the under-side of felled trees, and more especially to that type of undercutters which is adapted to be temporarily attached to the log during the period of operation.

The principal object of the invention is to provide an undercutter of extreme durability. A second object is to provide an undercutter capable of quick and convenient means for adjustment. A third object is to provide an undercutter whereby the saw may be kept in close contact with the work by taking up the slack without inordinate delay. A fourth object is to provide an undercutter the saw-rest arm of which is capable of being raised by being swung in either of two directions or in both directions alternately. Further objects are to provide an undercutter that is simple of construction, devoid of springs, easy to transport and exceedingly facile in operation.

To these ends, I have provided an undercutter which comprises a spike-shaped bar the pointed end of which may be driven into a log by blows upon the other end. Intermediate the ends of said bar there is rigidly attached a ratchet-wheel provided with cogs at frequent intervals, said cogs being notched in both edges so as to engage a pawl at either side. Oscillatingly suspended from said bar by a bolt passing therethrough and through said ratchet-wheel, is an auxiliary lever called a saw-rest arm, with a doublepointed pawl oscillatingly, riveted to said saw-rest arm at a point which allows the twin dogs to be thrown into engagement with the teeth of said ratchet-wheel. At the extremity of said saw-rest arm there is a rotatable grooved wheel which acts as. a trolley for the support and guidance of a saw the back of which rests in said groove. Said trolley-wheel is preferably attached to said saw-rest arm by the means shown in the drawings.

In the drawings, Figure 1 is a side view of the device; Figure 2 is a similar view of the opposite side; and Figure 3 is an edge view of the same.

The numeral 1 represents the spike-shaped bar, 2 its pointed end, 3 the saw-rest arm, 4 the trolley-wheel, 5 the double-acting pawl, 6 a bolt by which 3 is attached to 1, 7 the rivets which fasten the ratchet-wheel to 1, S a bolt by which is attached to 3, 9 a shoulder forming the terminal of 3, 10 said terminal of 3, 11 grooves in i, 12 the double ratchei wheel, and 13 the double-acting pawls or points on j The undercutters or drag-saw guides as they are sometimes called) heretofore provided lack durability, although over-weight log, in the position shown in Figures 1 and 2, or at any other desired angle to said log. The back of the saw is laid in the groove 11 of the trolley-Wheel 4, and the saw-rest arm 3 is so raised as to bring the teeth of the saw into contact with the log, it being retained in that position by the engagement of either of the pawl-points 13 with the doublenotched teeth of the ratchet-wheel 12. lVhenever and as often as it is found desirable to elevate the saw, the arm 3 is optionally swung in'either direction until one f the pawl-points 13 drops into engagement with the next notch in the ratchet-- wheel 12 The double-acting pawl, cooperating with numerous teeth'in the couple-acting ratchet, makes it possible to raise the saw-rest arm 3 as often as there is slack to be taken up, thus lessening the fatigue of the operator. This is very readily accomplished, without any necessity for alternately loosening and tightening the nuts and bolts with which other undercutters are provided, or any other loss of time and waste of physical exertion, because the latitude of its operation is enhanced by the short steps so provided, and the facility of manipulation is effected by the semiautomatic action of the twin pawls with the eooperating ratchet.

In attaching the various elements of my invention with and to the others, I have shown in the drawings the preferred or ordinary means, although any desired methods may be employed, and some variations may be made inthe construction of this device, without departing from the spirit of my invention.

I claim: 7

1. Au undercutter comprising a pointed bar provided with a double ratchet-wheel rigidly integral therewith, an oscillating saw-rest arm extending therefrom, said sawrest arm being provided with a rotatable grooved trolley-wheel and with an oscillating dog, and said oscillating dog having a plurality of pawls capable of engaging the teeth of said ratchet-wheel.

2. In an undercutter, a pointed bar provided with a ratchet-wheel rigidly integral therewith and intermediate the ends thereof, a saw-rest arm swingingly attached to said pointed bar and provided at its termination with a rotatable trolley-wheel and also provided with a swinging twin pawl either point of which is capable of being selectivelyplaced in engagement with a tooth of said ratchet-wheel when saidsaw-rest arm is raised to the desired position andof being retained in such engagement by the weight of said saw-rest arm bearing upon said pawl and ratchet.

A drag-saw guide comprising a pointed bar capable of being driven into a log, a saw-rest arm swingingly attached to said pointed bar andprovided with a trolleywheel and a swinging double-pointed pawl, a ratchet-wheel rigidly integral with said pointed bar, and said ratchet-wheel provided with doubly notched teeth capable of being engaged by'either point of said pawl. .4. An 'undercutter comprising a pointed bar capable of being driven into a log, in tegrally provided with a doubly-notched ratchet-wheel, asaw-rest arm bolted to said barand *said ratchet-wheel and provided with a double-pointed pawl the points of which are capable of being selectively placed in engageu'ient with the teeth of said ratchet-wheel, and the weight of said saw-rest arm capable of being supported and retained in a predetermined position by the contact. of said pawl witlrsaid ratchet.

' In testimony whereof have hereto atfixed my signature.

JFRED S. SMITH.

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