US2357230A

US2357230A - Power chain saw

Info

Publication number: US2357230A
Authority: US
Inventors: Shade Robert William
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-06-30
Filing date: 1942-06-30
Publication date: 1944-08-29
Anticipated expiration: 1961-08-29

Description

Aug. 29, 1944. R. w. SHADE I POWER CHAIN SAW Filed June 30, 1942 INVE N 70/? R05 ERT WILL/A M5/1ADE ATTORNEY Patented Aug. 29, 19%

Robert William Shade, Vancouver, British 1 Columbia, Canada Application June 30, 1942, Serial No.'449,138

3 Claims.

My invention relates to improvements in power chain saws, particularly those which are used in the woods for bucking fallen timber.

The usual type of power chain saw is provided with a prime mover at one end which is either a gasoline engine or an electric motor, th prime mover being provided with a pair of handles by which it and the saw'is manipulated by an operator and at the outer end of the saw another pair of handles are provided. When using the saw for bucking falln trees the handle or handles at the outer end are of little valu and are in many cases a hindrance, since they make it diflicult to enter the free end of the saw cutter bar into' the place where a cut may be required. At the free end of the usual power saw cutter bar a sheave is provided over which the chain saw passes and the sheave is spring mounted to provide a resilient tension on the chain saw so that shocks imparted to the saw by knots or other obstructions while cutting are'not fully transmitted to the operator. The above construction makes the free end of the saw cumbersome and does not permit the saw to be withdrawn lengthwise through a cut, should it be desirable.

With a view to overcoming the above and other defects the present invention is designed so that no spring mounted sheave is required at the outer end of the cutter bar, and to prevent any shock to the even running of the chain saw being transmitted to the operator handling th saw.

Referring to the drawing,

Fig. 1 is a side elevation of the invention showing a portion of the strut cut away and exposing the drive sprocket.

Fig. 2 is a plan view.

In the drawing like characters of reference indicate corresponding parts in each figure.

The numeral I indicates a gasoline engine provided with a transmissioncase 2 on the side of which a drive sprocket 3 is mounted. The sprocket 8 is driven through a clutch 4 omitted from Figure 1, which is operated byv a lever 5 on the opposite side of the transmission case 2.

The engine has a pair of hinge brackets 6 extending horizontally forward from its cylinder I and is connected by a pin 8 to a pair of brackets 8 which are carried upon the strut H] of the saw. The strut is so constructed as to provide a vertical slot I! in which is rigidly secured the inner end of a cutter bar I3 and leave upper and lower openings l4 through which an endless chain saw I! may pass.

The cutter bar I3 consists of a plate cambered upon its upper and lower edges as at It, having its free end semi-circular as at IT and its inner end arcuately tapered to less than the diameter of the driven sprocket 3, as indicated at I8. The cutter bar [8 is provided with a peripheral groove l9 indicated in dotted line in Figure .1 to receive the driving teeth of the chain saw and form a guide track therefor in the usual way. Adjacent the outer end of the cutter bar an opening 2| is provided toserve as a hand hole for lifting the forward end of the device when placing it in position upon a log or removing it from one place to another.

Extending from the strut l 8 is a pair of handle bars 23 which are connected together by a cross bar 24 and are fitted with handles or grips 25 at their outer ends. A bolt 21 is hingedly connected to the base of the strut l0 and passes through an upturned bracket 28 mounted on the base of the engine. The bolt is provided with a compression spring 29 which urges the engine away from the strut l0 and resiliently tensions the chain saw l5 upon the cutter bar l3 and the sprocket 3. The compression of the spring 28 is such as to support the engine in normal position as shown within its mounting between the handle bars 23 when the saw is cutting under normal load or when at rest.

In operation, the device is set with the strut in contact with the log or other work to be sawn and since the device operates on the draw out the drag of the saw will hold the strut firmly in abutment against the work. If a knot or other temporary obstruction is encountered by the chain saw l5 the momentum and power of the engine will cause the engine I to swing aboutthe pin 8 with the sprocket 3 swinging along th are shown in dotted line in Figure 1 as at X.

The above engine movement will provide a -small amount of slack in the upper run of the chain saw, some of which will develop in a slight sag 'between the sprocket 3 and the tapered inner end I8 of the cutter bar l3.

The resistance to free movement of the upper run of the chain saw in the kerf will prevent any slack developing at the free end of the frame.

It is obvious that other means may be adopted to mount the engine to move the prime mover towards and away from the strut and to provide cushioning means'between said parts.

What I claim as my invention is:

1. A power driven chain saw comprising a strut having a pair of spaced supports extending rearwardly therefrom, a cutter bar extending torwardly from said strut and being rigidly connected thereto, a prime mover connected to the strut and having movement between the spaced supports in' the direction of the cutter bar, a, chain saw extending around the cutter bar, said prime mover having a, sprocket for driving the chain saw and spring means interposed between the strut and the prime mover for resiliently tensioning th saw upon the cutter bar.

2; A power driven chain saw comprising a. strut having a pair of spaced supports extending rearwardly therefrom, a cutter bar extending ior-' wardly from said strut and being rigidly connected thereto, a. bracket extending from the strut, a prime mover having a sprocket hingedly connected to said bracket and having movement between the spaced supports, a chain saw surround- 10 bar, a prime mover having a sprocket tor driving the chain, said prime mover being pivotally connected from the strut for swinging movement between said bars, and a compression spring interposed between the strut and the prime mover 15 for resiliently tensioning the chain.

ROBERT WILLIAM SHADE.