Metal tools and implements – making – Saw-making or furbishing device or machine – Sharpening and gumming
Patent
1992-08-19
1993-09-07
Parker, Roscoe V.
Metal tools and implements, making
Saw-making or furbishing device or machine
Sharpening and gumming
33202, B23D 6310
Patent
active
052418820
DESCRIPTION:
BRIEF SUMMARY
FIELD OF USE
Saw chains for chainsaws are most commonly chisel-type, with a cutter formed on a sidelink the upper part of which has been bent perpendicularly to the guidebar and a depth gauge in front of the cutter. Examples of such chains are the U.S. Pat. Nos. 2,508,784 and 2,725,083. Sharpening of the chain is done with a file and comprises three steps: right hand cutters, left hand cutters and depth gauges. Each cutter has one side edge and one transversal edge, both of which can be sharpened simultaneously with a round file. The sharpening operation is relatively simple, but for maximum efficiency and safety the file must be held correctly with respect to height, transversal angle and vertical angle. The depth gauge shall slope slightly forwards, and the difference in height between its peak and the transversal edge shall have a prescribed value. Experience shows that some kind of filing gauge is needed for these operations, and numerous types of filing gauges have been suggested.
Accuracy in filing is the most important requirement for a filing gauge, but other demands are that filing should be possible with one hand on the file without holding the filing gauge, and that the file should be supported by rollers at least when sharpening the edges to avoid excessive wear, and that the position of the filing gauge should be determined by the chain rather than by the guide bar, with consideration of the play of the saw chain in the groove on the guide bar.
PRIOR ART
Filing gauges where the file is guided by rollers are known from the U.S. Pat. No. 4,131,038, comprising a channel laid over at least two cutter links, an indexable angular plate which is adjusted to the desired transversal angle according to a scale and one springloaded plate movable against the angular plate and carrying two guide roller with axes parallel to the flat sides of the guide bar. Disadvantages with this type of filing gauge are the need for resetting the angular plate when proceeding from right hand cutters to left hand cutters, an intricate design with numerous components and lacking control of the vertical angle.
The U.S. Pat. No. 4,228,702 describes a filing gauge with four rollers, with no need for readjustment between right and left hand, but this is also mechanically intricate with several springs, and is to be affixed to the guide bar with screw clamps, which makes control of the vertical angle impossible.
Filing gauges oriented by the saw chain links are known from the U.S. Pat. No. 4,745,827, where a support plate is secured to the saw chain by two narrow prongs inserted between the pairs of sidelinks in front and rear of the cutter link. The transversal angle is estimated with aid of sighting lines and the vertical angle is determined by the support plate. One disadvantage is that the file will rub against the support plate with great force when filing the edges, which wears the file and the plate excessively.
A filing gauge according to the U.S. Pat. No. 4,738,165 has a support plate oriented by the saw chain by cutouts in contact with the outside of the pairs of sidelinks in front and rear of of the cutting link. The entire support plate is sloping slightly in the longitudinal direction of the chain, thereby assuring a desired relation between the transversal and vertical angles. There is no guidance for the transversal angle, however, and the file rubs against the plate when filing the edges. A parallel row of holes in the same support plate is used in filing the depth gauge.
The present invention concerns a filing gauge which facilitates filing the cutter with controlled transversal and vertical angles, and with minimal wear of the file, and also filing of the depth gauge with the optimal slope.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 show the filing gauge when used in filing the cutter of a cutter link,
FIG. 3 when used in filing the depth gauge and
FIG. 4 a view in the direction of the file.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The saw chain runs around the guide bar (10) and comprises driveli
REFERENCES:
patent: 2508784 (1950-05-01), Cox
patent: 2662423 (1953-12-01), Greenlee
patent: 2725083 (1955-11-01), Ackley
patent: 3905118 (1975-09-01), Ballew
patent: 4131038 (1978-12-01), Beerens
patent: 4228702 (1980-10-01), Stewart et al.
patent: 4412463 (1983-11-01), Beerens
patent: 4738165 (1988-04-01), Gelman
patent: 4745827 (1988-05-01), Kuwica
Parker Roscoe V.
Sandvik AB
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