Cutting – Cutter assemblage or cutter element therefor – Having noncutting depth gauge
Reexamination Certificate
1999-09-27
2001-10-30
Peterson, Kenneth E. (Department: 3724)
Cutting
Cutter assemblage or cutter element therefor
Having noncutting depth gauge
C083S830000
Reexamination Certificate
active
06308606
ABSTRACT:
BACKGROUND OF THE INVENTION
A saw chain for a motor-driven chain saw is disclosed in U.S. Pat. No. 2,928,440. The cutting links arranged in the saw chain have a roof surface that is bent over the saw chain whereby a chip channel is formed between the center drive link and the roof surface of the lateral adjacent cutting tooth. The edge of the drive link faces toward the roof surface and defines a uniform recess. The deepest location of this recess lies in the center between the rivet holes of the drive link as seen in side elevation.
Problems can occur with respect to the removal of chips in dependence upon the material to be cut. The chip channel can become clogged whereby the cutting power is affected.
SUMMARY OF THE INVENTION
It is an object of the invention to improve a saw chain of the kind referred to above so that a high cutting power is achieved with a simple configuration and a low forward thrust force.
The saw chain of the invention is for a motor-driven chain saw. The saw chain defines a longitudinal axis and includes: a plurality of center drive links and a plurality of side connecting links, the links being pivotally interconnected by rivets lying transversely to the longitudinal axis; the saw chain defining a center plane passing through the longitudinal axis; a portion of the connecting links being configured as cutting links; each one of the cutting links including a rearward wall portion bent over toward the center plane to define a cutting tooth having a roof; the roof having a leading edge extending transversely to the center plane and defining a cutting edge; the roof also having a trailing edge extending transversely to the center plane and the trailing edge being at a lower elevation than the leading edge; individual ones of the drive links each having a body defining two rivet holes formed therein and each one of the individual ones of the drive links having an upper edge; the upper edge having a region extending between first and second imaginary lines passing through the rivet holes perpendicular to the longitudinal axis; the upper edge having a recess formed therein in the region; the trailing edge of the roof extending over the recess at a distance therefrom and the recess delimiting a chip channel for guiding chips cut by the cutting edge; the rivet holes having center points connected by an imaginary line; and, the recess, when viewed in side elevation, being configured in the region of the upper edge to be asymmetrical relative to an imaginary center perpendicular bisecting the imaginary line into two equal segments.
It has been surprisingly shown that already an asymmetric configuration of the recess leads to a significant increase in cutting power for a constant forward thrust force with the assembly otherwise being unchanged. In practice, an improvement of the cutting power of over 15% with a high mechanical strength of the chain has been determined for a configuration of an asymmetrical recess on the center drive link. Even the configuration of an asymmetrical edge of an outside connecting link leads to an improved cutting power. This configuration on the external cutting link can, for example, be an asymmetrical recess.
In this connection, it has been shown to be advantageous to make up the recess from at least two differently steep edge sections. The transition from the leading edge section to the trailing edge section can be rounded as well as be configured at an angle. The edge sections delimit an angle preferably greater than 90°.
Advantageously, the leading edge section defines an inclined plane which runs approximately parallel to the roof surface of the cutting tooth. When the inclined plane drops off at a somewhat larger angle in a direction opposite to the running direction of the saw chain than the magnitude of the free angle of the roof surface, then the chip channel expands in opposition to the running direction of the chain thereby countering clogging. The chip channel is formed between the edge of the drive link and the roof surface. The trailing edge section increases steeply in a direction opposite to the running direction of the saw chain and extends from the leading edge section. The trailing edge section imparts to the chip a component of movement inclined toward the outside and away from the saw chain whereby a good removal of the chip is ensured.
In a preferred embodiment, the deepest location of the depression is provided in the running direction of the saw chain behind the trailing edge of the roof area and is advantageously approximately in the region of the trailing rivet hole of the drive link.
REFERENCES:
patent: 2928440 (1960-03-01), Fors
patent: 3291169 (1966-12-01), Morner
patent: 3329183 (1967-07-01), Robinson
patent: 3444907 (1969-05-01), Chadwick
patent: 4459890 (1984-07-01), Dolata et al.
patent: 4581968 (1986-04-01), Gibson et al.
patent: 4593591 (1986-06-01), Beerens
patent: 5257568 (1993-11-01), Nitschmann
patent: 6058825 (2000-05-01), Harfst
Andress Bernd
Buchholtz Jochen
Andreas Stihl AG & Co.
Choi Stephen
Ottesen Walter
Peterson Kenneth E.
LandOfFree
Saw chain for a motor-driven chain saw does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Saw chain for a motor-driven chain saw, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Saw chain for a motor-driven chain saw will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2611186