US2921613A - Chain saw bar - Google Patents

Description

Jan. 19, 1960 E. H. SILVEY CHAIN SAW BAR FiledSept. 11, 195'! R. m In M N H v m M 0 limited States Patent 6 2,921,613 CHAIN SAW BAR Ernest H. Silvey, Prineville, Oreg. Application September 11, 1957, Serial No. 683,283 2 Claims. (Cl. 143-32) This invention relates to chain saws and more particularly to an attachment for the guide bar of a chain saw to prevent the chain from leaving the bar.

Occasionally the chain of a chain saw leaves its bar and causes damage to the motor, chain and bar. This invention provides means which are attached to the front and rear surfaces of the guide bar and protrude to a point below the outer surface of the teeth on the chain. The small fiat pieces that constitute the guides on the guide bar and prevent the chain from separating from the guide bar, are located at the base of the bar. It has been found that these small guides are all that is necessary to prevent inadvertent skipping of the chain from the guide bar.

Hardware of any type applied to the working area of the bar or at the tip of the bar interfere with the free use of the chain saw. I emphasize further that protrusions of any kind which are located along the bar which is ordinarily used for sawing operations, are objectionable. I further emphasize that my guides are in addition to the means for attaching the guide bar to the saw frame and constitute no part thereof. My invention is embodied in separate small pieces which are welded or otherwise fastened to the base of the chain guide bar and thereby become fixed as a. part thereof. When the guide bar is removed in favor of another, additional guides will have to be applied onto the new guide bar to make it improved andto fall within the purview of my invention.

Other objects and features will become apparent in following the description of the illustrated form of the invention.

Figure 1 is an elevational side view of an ordinary chain saw, parts being broken away to show the guides of the invention applied operatively on the saw;

Figure 2 is an enlarged cross-sectional view taken on the line 22 of Figure 1 and showing that the guide parts are located on each side of the chain guide bar and chain and to show that their upper edges terminate below the outer edge of the sawteeth;

Figure 3 is a fragmentary perspective view of the guide bar having guides thereon;

Figure 4 is a top view of a part of the guide bar and guides;

Figure 5 is a perspective view in reduced scale of a modification of the invention.

In the accompanying drawing there is a chain saw 10 which schematically represents any manufacturers make. All saws of the general class under discussion have frames 12 to which a guide bar 14 is secured. The means 16 for attaching the guide bar 14 to the frame differ from one manufacturers make to the other. ,The illustrated means 16 are quick disconnect fastening devices which pass through slots in the inner end of bar 14. Chain 18 is driven by the engine in the power saw and is guided by channel 20 along the edge of guide bar 14. Teeth 22 on chain 13 are conventional as is all of the structure described herein to this point.

My invention is embodied in two pairs 24 and 26 of guides which are Welded or otherwise fastened to the base and bar 14 alongside of the channel 20. The pair of guides 24 consists of two flat parts or plates 28 and 30 that are approximately rectangular and that have their lower longer edge part Welded or otherwise fastened to the bar 14 on opposite sides of channel 2%. The plates protrude outwardly from the channel 26* and also from the periphery of the bar 14. They form between them a passageway 32 that constitutes a lateral extension of channel 20 and that is considerably wider than channel 20. The teeth of the chain fit therebetween and are guided in their travel. The front corners, considered with reference to the direction of travel of the chain, have outwardly tapered surfaces 38 and 40 in order to prevent the links of the chain from becoming snagged on a sharp corner and to further aid in guiding the chain links smoothly into the passageway 32. By having the guides located where illustrated in Figure 1, they cannot interfere with the use of the saw and yet they are very successful in preventing the saw chain from jumping from its channel 20.

The pair 26 is identical to the pair 24 of guides and is located across the bar 14 from the pair 24. Although one pair is all that is necessary, the guides are so inexpensive that both pairs are recommended.

In Figure 5, guide bar 44 is illustrated. A pair of guides 46 and 47 are welded, bolted or fastened by other means to the inner end of bar 44. Guides 46 and 47 have their ends protruding from the edges of bar 44 to form a lateral extension of the chain passageway and are otherwise the same in function as guides' 24 and 26. The distinction between the embodiments of Figures 3 and 5 is that both guide plates on one side of the bar are integrally connected in FigureS and made separate in Figure 3.

It is understood that various changes and modifications may be made without departing from the invention.

What is claimed as new is as follows:

1. In combination with the guide bar having a longitudinal center line and used as a part of a chain saw which has a tooth supporting chain guided in a channel along the edge of the guide bar, means at the inner part of the bar for preventing the chain from skipping from the channel, said means comprising a pair of guides which are fixed directly to said bar on opposite surfaces thereof and which protrude beyond the edge of the bar and which are arranged to form a passageway for the chain, and said guides located entirely on one side of said longitudinal center line.

2. In combination with the guide bar having a longitudinal center line and forming a part of a chain saw which has a body, a tooth supporting chain guided in a channel along the edge of the guide bar, means spaced from said body and located at the inner part of the bar for preventing the chain from skippingfrom the channel, said means comprising a pair of guides which are immovably fixed directly to said bar on opposite surfaces thereof and which protrude beyond the edge of the bar and which are arranged to form a passageway for the chain, said guides located entirely on one side of said longitudinal center line, said passageway constituting a lateral extension of said channel and being wider than said channel, and portions of said guides at the leading edges thereof being outwardly flared to form a guide to facilitate the links of the chain entering said passageway.

References Cited in the file of this patent UNITED STATES PATENTS 2,434,884 Kottmann et al. Jan. 20, 1948 2,798,516 Heal et a1. July 9, 1957 2,827,932 Strunk Mar. 25, 1958 FOREIGN PATENTS 578,826 Great Britain July 12, 1946

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