Improvements made to the devices for grinding and polishing the wall of the bores of tubes or other objects

摘要

873,133. Valves. CHAFFEY, S. J. Jan. 27, 1960 [Jan. 27, 1959], No. 2836/59. Class 135. [Also in Group XXIII] Polishing or like apparatus comprises a hollow member adapted to be connected to a pressure fluid supply source and adapted to have secured thereto in a removable manner a polishing or like unit provided with pressure fluid-operated cutting elements, the hollow member incorporating a valve which is biased into a closed position to prevent the passage of the pressure fluid through the hollow member to the polishing or like unit and which valve is adapted to be opened by the pressure fluid from the supply source operating against the bias to permit passage of the pressure fluid to the polishing or like unit to operate the cutting elements of the unit. A polishing tool 10 is secured by an adaptor 13 to a hollow driving spindle 17. A piston 19 is movable in a chamber 20 in the spindle 17, a spring 34 being interposed between the piston 19 and an end face 36 of the adaptor 13. The piston 19 is formed with a seat for the head 27 of a valve, the stem of which has a part 28 passing through a duct 26 in the piston 19 and a part 29 guided in a bore 30 in the adaptor 13. A spring 31 is interposed between the piston 19 and a stop peg 32 extending through an enlarged diameter portion 33 of the valve stem. The valve is thus closed when the piston 19 is in its upper position. When fluid pressure is admitted to the interior of the spindle 17, the piston 19 is moved towards the adaptor 13; eventually the portion 33 abuts the face 36 of the adaptor whereafter the valve is opened by further movement of the piston 19 which movement is limited by abutment of the piston 19 with the adaptor 13. The fluid then passes through the duct 26 in the piston 19 and through ducts 37 in the adaptor 13 to the interior 38 of the tool 10 and moves the working elements 49 outwardly into contact with the wall of the workpiece. When the fluid pressure is reduced or cut off the spring 34 moves the piston 19 away from the adaptor 13 allowing the spring 31 to shut the valve. The continued movement of the piston 19 away from the adaptor 13 reduces the pressure in the interior 38 allowing the working elements 49 to move inwardly out of contact with the wall of the workpiece so that the tool can be withdrawn axially without scoring or flaring the end of the workpiece. The tool is substantially the same as that described in Specification 873,132 [Group XXIII].