GB338696A - Improvements in or relating to means for operating the distributing slide valve of pressure air operated hammers - Google Patents

Abstract

338,696. Frankfurter Maschinenbau-Akt.-Ges. vorm. Pokorny & Wittekind, and K³hn, W. Oct. 24,1928, [Convention date]. Percussive hand tools.-In a fluid-pressure hammer, a sleeve valve is arranged at the end of the cylinder coaxially therewith, and is moved in one direction by the compression, and in the other direction by fluid pressure supplied from the cylinder to an annular area on a shoulder on the valve. The auxiliary passage is provided with a non-return flap valve. The main valve s is locked in both control positions. When the piston d descends and uncovers the port g fluidpressure passes from the cylinder to the annular area i and raises the valve against the excess fluid-pressure on its upper end. Port g is closed by a flap valve c which is mounted in a bore k closed by a screw cap and prevents the exhaust of the valve chamber when the main exhaust is opened. After the valve has been reversed, air passes by passage f to the bottom of the cylinder and forces the piston upwards. During the upward stroke, a port h is uncovered and the pressure retains the valve s in its raised position since the area i is greater than the area q, and both areas are subject to the pressure in passage f. When the piston enters the valve, the compression forces the valve downwards, which closes passage m and opens passage n to effect the down piston stroke. During the down stroke the air in front of. area i exhausts through port h and passage f. In a modification, the valve c is arranged in a separate casing with a T-shaped slot.