Patent EA-000372-B1 (EA)
Title: Method of assembling a chain and a rivet for use in such assembly
Inventor: TRAVIS THOMAS N R
IPC: B27B33/14
Filed: 1997-02-18
Abstract: 1. A rivet blank for interconnecting two side links and a centre link of a saw chain, the rivet blank comprising: a centre flange (33) of generally cylindrical shape defining a centre axis, and a pair of barrels for being staked and deformed to fill holes of respective side links of a saw chain, the barrels extending outwardly from opposite sides of the flange along the centre line thereof, each barrel including before deformation an axially outer tapering section and an axially inner cylindrical section. 2. The rivet blank according to Claim 1, wherein each cylindrical section occupies about one half of the axial length of its respective barrel. 3. The rivet blank according to Claim 1, wherein the axial inner end of the tapering section coincides with the axial outer end of its associated cylindrical section. 4. The rivet blank according to Claim 3, wherein each cylindrical section occupies more than half of the axial length of its respective barrel. 5. The rivet blank according to Claim 4, wherein the outer surface of the tapering section forms an angle in the range of about 5-20 degrees with a line parallel to the centre axis. 6. The rivet blank according to Claim 5, wherein the angle is substantially 10 degrees. 7. The rivet blank according to Claim 1, wherein the outer surface of the tapering section forms an angle in the range of about 5-20 degrees with a line parallel to the centre axis. 8. The rivet blank according to Claim 1, wherein the centre flange has axially facing surfaces which are slightly undercut. 9. A method of forming a saw chain, comprising the steps of: A) providing a pair of side links (20) and a centre link (21) disposed between the side links such that holes in the side links and centre link are aligned with one another, each hole of the side links including a cylindrical portion (22) and a chamfered portion (23), the chamfered portion disposed in an outer surface (20A) of a side link, the outer surface facing away from the centre link; B) providing a rivet blank comprising a generally cylindrical flange (33) and a pair of barrels projecting outwardly from opposite sides of the cylindrical portion along a longitudinal axis of the cylindrical flange, each barrel including an axial inner cylindrical section (34A) and an axial outer tapering section (34B); C) positioning the rivet blank so that the generally cylindrical flange is situated in the hole of the center link, and each barrel is situated in a hole of a respective side link, with the cylindrical section thereof disposed in the cylindrical portion of the hole and the tapering section thereof disposed in the chamfered portion of the hole; and D) staking the barrels such that the cylindrical and tapering sections of the barrels are deformed to fill the respective cylindrical and chamfered portions of the hole. 10. The method according to Claim 9, wherein step D comprises causing the staked barrels after deformation to press against walls of the cylindrical portions of the holes with a first force, and to press against the chamfered portions with a second force stronger than the first force. 11. The method according to Claim 9, wherein step D comprises causing the tapered section of each barrel to form a rivet head filling its respective chamfered portion of the hole and having a convex outer surface (7) extending outside of the outer link surface (20A).