Patent ID: 6338375
Filing Date: 2002-01-15
Classification: B29C,B29L,B65B

Abstract:
A tool for tightening and melt-adhering a strap, with which a loose strap wound round a package is tightened by a tightening roller arranged at the overlapped portion of the strap to form a tight strap, an extra strap is cut and removed by a cutter, and a frictional force is imparted to the overlapped portion of the strap to melt-adhere the strap, wherein provision is made of a fluid pressure cylinder for pressurizing the tightening roller, a first fluid pressure motor for turning said roller forward and reverse, a fluid pressure cylinder for pressurizing a vibrator that gives a frictional force to the overlapped portion of the strap, and a second fluid pressure motor for driving said vibrator, a fluid pressure timing mechanism, wherein the fluid pressure timing mechanism is a variable back pressure type in which at least one of the fluid accumulation chambers branched from a main pressurized fluid circuit has a variable back pressure valve for releasing the fluid back pressure, said fluid pressure timing mechanism being further equipped with a shut-off valve which shuts off the main pressurized fluid circuit to the second fluid pressure motor relying upon a fluid pressure stored in the fluid accumulation chamber.