Piston retention apparatus and method

摘要

An apparatus and method for coupling a piston to a rod to form a cylinder assembly are provided. The piston has a tapped bore extending therethrough for coupling to a first threaded region of the rod. The rod end extends beyond the piston member and includes a second threaded region for coupling to a tapped bore of a retaining member. The piston member is coupled to the rod member at a low torque, e.g., up to about 1000 Nm. An external thread of each of the threaded segment of the piston bore and the first threaded region of the first portion of the rod member may be formed with a root radius of greater than 0.125 pitch or with MJ class thread. The retaining member may include setscrews offset from one another for frictional engagement with the rod end. The thread pitch between the rod and the piston may be coarser than between the rod and the retaining member. An interface and a seal region between the rod and the piston may be disposed closer to the rod end side of the piston member than the threaded coupling.

主权项

1. A piston and rod assembly for use with an actuating device, comprising:
a piston member having a piston bore extending between a first end and a second end, the piston bore having a threaded segment; a rod member having a first threaded region threadably engaged with the threaded segment of the piston bore, an end region extending beyond the second end of the piston member, and a second threaded region at the end region; and a retaining member having a retaining bore extending therein, the retaining bore having a threaded portion threadably engaged with the second threaded region, wherein an external thread of each of the threaded segment and the first threaded region has a pitch and is formed with a root radius of greater than 0.125 pitch.