This application claims priority of German patent application no. 10 2007 050 778.1, filed Oct. 24, 2007, the entire content of which is incorporated herein by reference.
U.S. Pat. No. 3,519,039 discloses a cutting link for a saw chain which has an essentially planar base plate having flat sides parallel to each other. In this base plate, openings are provided which accommodate rivets for connecting to additional chain links. A cutting tooth is attached to the base plate and projects somewhat-beyond the rearward end of a recess in the base plate. The cutting tooth is made of hard metal and is bonded to the base plate via brazing.
With respect to its configuration, the known cutting tooth is relatively massive and the cutting tooth engages over the base plate at both sides at its upper edge in order to provide a reliable bond. In this way, the configuration of the cutting tooth is complicated and this leads to a high complexity with respect to manufacture.
International patent publication WO 2004/113035 A2 discloses a cutting link for a saw chain which comprises a base body and a cutting tooth attached thereon. The base body is provided with a laterally projecting wedge tapered in the running direction of the cutting link and this wedge serves to provide a form-tight accommodation of the cutting tooth. The cutting tooth has essentially a U-shaped cross section with a corresponding lateral slot which has a form complementary to the base body so that the cutting tooth is attached on the base body via insertion. The cutting tooth is made of a hard metal.
It is apparent that this configuration of the base body and the cutting tooth is most complex and leads to very high costs, especially because the mass of the necessary hard metal is relatively large.
It is an object of the invention to provide a cutting link of the type described above wherein a reliable attachment of the cutting tooth to the base body is provided also with a simple configuration of the cutting tooth and for a small dimensioned cutting link.
The cutting link of the invention is for a saw chain having a running direction (A). The cutting link defines a horizontal axis (H) and includes: a base body being a planar plate and having first and second rivet openings formed therein; a cutting tooth made of hard metal and attached to the base body; the cutting tooth having a roof section and a connecting leg; the base body having a recess formed therein forward of the cutting tooth viewed in the running direction (A) for conducting away chips; the cutting tooth partially overlapping the recess; the connecting leg being in surface contact with the base body laterally thereof; the cutting tooth and the base body being firmly bonded to each other by brazing utilizing a brazing solder; the connecting leg having a first edge in the form of a lower edge and the connecting leg extending downwardly so far that the lower edge lies lower than the recess; the connecting leg having, viewed in the running direction (A), a rearward region; and, the rearward region of the connecting leg having an upwardly pulled second edge lying opposite one of the rivet openings.
The cutting link of the invention is simple in assembly and can therefore be cost effectively manufactured. Because of the large connecting surface for the firm bond, a reliable hold of the cutting tooth on the base body is provided. A mounting of the rivets in the assembly of the saw chain is not hindered because of the special configuration of the cutting tooth in the region next to the rivet opening.
According to a practical embodiment of the cutting link, a bevel is provided at the lower edge of the connecting leg. This bevel facilitates the chip flow. Furthermore, it is practical that the edge runs upwardly inclined in the direction toward a rearward end of the base body at an angle to the horizontal axis. The angle of this edge referred to a horizontal of the base body preferably lies in the region of approximately 15°. A silver solder is especially suitable for the brazed bond of the cutting tooth and base body. The soldering temperatures lie in a range between 700° C. and 750° C., that is, in a temperature range which does not have a negative effect on the hardened material in the functionally relevant region of the cutting tooth.
The lateral cutting edge of the cutting tooth is preferably configured in the form of a concave channel. The lateral cutting edge has a bevel on the side facing toward the base body. The bevel angle is approximately 40° referred to the longitudinal direction of the cutting link.
To improve the chip flow, a bevel is provided at the recess for chip diversion in the rearward region of the recess. A stop is formed at the upper edge of the base body against which a rearward end of the cutting tooth lies. In this way, a form-tight connection of the base body and cutting tooth is additionally provided in the longitudinal direction of the cutting link. It is furthermore practical that the cutting tooth covers the recess to such an extent that the sharpening of the cutting edge is possible without a removal of material of the base body.
The invention will now be described with reference to the drawings wherein:
The cutting tooth 3 includes a roof section 7 which extends over the upper end of the base body 2 and has a connecting leg 8 which lies against the side of the base body 2 and provides a large-area connection of the cutting tooth 3 to the base body 2. The connecting leg 8 projects so far downwardly that a lower edge 13 lies deeper than the base of the recess 6.
A rearward edge 9 of the cutting tooth 3 lies against a stop 10 which is formed on the upper edge of the base body 2. The cutting tooth 3 has a roof cutting edge 11 and a lateral cutting edge 12 which are disposed in the region of the rearward end of the recess 6. The lower edge 13 of the connecting leg 8 is provided with a bevel 14. The chip removal is improved with this configuration.
It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and-scope of the invention as defined in the appended claims.
Number | Date | Country | Kind |
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10 2007 050 778.1 | Oct 2007 | DE | national |