A New or Improved Adjustable Shore or Strut for use in Supporting the Sides of Earth Trenches, and the like Excavations, while under Construction.

摘要

15,645. Douglas, J., and Christie, W. July 14. Lifting-jacks.-An apparatus resembling a lifting- jack is employed to replace the ordinary wood struts used in shoring the sides of earth trenches. Two pistons B, C, with spread-out roughened feet L, are inserted in a tubular body A. The piston B has a number of holes and can be secured in a roughlyadjusted position by a pin. For finer adjustment, a cam-lever F levers out the piston C, which is formed with rack tee'.h held by a detent K which can be knocked out to dismount the apparatus.