Back to results
US 2009/0255393 A1Published application
Shear resistant rivet and saw chain
AssigneeBlount, Inc.
InventorsChris Seigneur, David Scott Penrose
Life of this patent
Estimating the term…
Abstract
A saw chain rivet is provided including a flange, and a hub extending from a side of the flange. A shoulder defined by a junction between the hub and the flange has properties optimized to resist shear forces. The hub may be optimized for ease of rivet head formation.
Claims8
A rivet for securing side links to center links of a cutting chain comprising:
- a flange portion having a circumferential surface positioned to engage a rivet hole of a center link, the circumferential surface having a first hardness;
- opposing hub portions extending from opposing sides of the flange for engaging rivet holes of side links, the hub portions having a second hardness;
- and
- opposing shoulder portions, each defined by a junction between the flange and a respective hub and that extends at least partially into the flange portion and the hub portion, wherein the shoulder portions are subjected to a shearing force during a cutting operation of the saw chain, said shoulder portions treated to have a third hardness that is less than the first hardness and greater than the second hardness.
1 more element
A cutting chain, comprising:
- a center link having a center link rivet holes;
- a side link pair adapted to couple to the center link on opposing sides of the center link, each side link of the side link pair having a side link rivet hole;
- a rivet disposed in the center link rivet hole and the side link rivet holes, wherein the rivet has opposing ends that are enlarged to couple the side link pair to the center link, the rivet further having a center flange portion disposed between two hub portions, the center flange portion having a circumferential surface having a first hardness and positioned to rotatably engage center link rivet hole, the two hub portions extending from opposing sides of the flange and having a diameter less than or equal to a diameter of the side link rivet holes, the hub portions having a second hardness, and shoulder portions defined by a junction between the flange and respective hub portions that extends at least partially into the center flange portion and the hub portion, wherein the shoulder portions are subjected to a shearing force during a cutting operation of the saw chain, wherein the shoulder portions are treated to a third hardness that is less than the first hardness and greater than the second hardness.
A method of rivet formation for a rivet suitable for withstanding the forces encountered in cutting chains, comprising:
- Providing a rivet having a center flange portion with a circumferential surface adapted to rotatably engage a center link rivet hole, opposing hub portions extending outwardly from the center flange portion and a shoulder portion defined by a junction between one hub portion and the flange portion, wherein each shoulder extends at least partially into the center flange portion and partially into one of the hub portions;
- Heat-treating the rivet to a predefined first hardness;
- and
- Performing two of the following:
- selectively adjusting the hardness of the circumferential surface of the center flange portion by heat-treating or tempering the shoulder portion to a desired circumferential surface hardness
- selectively adjusting the strength of the shoulder portion by heat-treating or tempering the shoulder portion to a desired shoulder hardness;
- and
- selectively adjusting the hardness of at least a portion of each hub portion to a desired hub hardness.
5 more elements
Dependencies are inferred from the claim text.