Patent ID: 8202022

Claim:
A method of making a vibratory percussion rammer, the method comprising: providing a motor-driven gearbox and a percussion unit extending downwardly from the gearbox, the percussion unit comprising a ram and shaft assembly extending downwardly from the gearbox into a guide cylinder, a spring box extending upwardly into the guide cylinder, and a spring separator coupled to the ram and shaft assembly and disposed in the spring box between upper and lower springs, the ram and shaft assembly configured to reciprocate up and down and the spring box configured to reciprocate divergently relative to the reciprocations of the ram and shaft assembly; forming a slide bearing out of a sheet of non-metal material having a length and a width by shaping the sheet into a tube having a C-shape in cross-section that defines an open seam having a width between opposed seam edges and extending along the entire length of the slide bearing; sizing the sheet so that the open seam is wider than an anticipated width-wise thermal expansion of the slide bearing during normal operation of the vibratory percussion rammer; selecting the width of the seam such that, in the event the operating temperature of the rammer exceeds a selected high temperature above a normal operating temperature, the seam will close reducing the seam to abutting closure of the seam edges; and inserting the slide bearing between adjacent surfaces of reciprocating metal components.