GB915649A - - Google Patents

Abstract

915,649. Bark removing. NELSON, P. V. Sept. 12, 1961, No. 32733/61. Class 145. [Also in Groups XXIX and XXXII] The pivoted tool arms 3 of the rotary ring 1 of a barking machine are pressed against the log L by sealed fluid pressure means which exerts a continuously and rapidly-increasing pressure as the arms move outwardly to accommodate larger logs. An extensible hydraulic strut 8, Fig. 3, or 17, Fig. 4, extends between each arm 3 and a pivot 9 on the ring 1 and the movement of the arms is limited by stops 7 and a bumper pad 5. Silicone liquid may be used as the hydraulic fluid. The strut 17, Fig. 4, comprises a cylinder with a core 18 slidable sealingly within the sleeve 20 of a plunger 19 and as the strut is compressed the entry of more of the sleeve increasingly compresses the liquid. The initial pressure of the liquid is set by screwing in a filling bolt 26 to reduce the effective size of the cylinder and can be increased by screwing in a second bolt 26<SP>1</SP>. In a modified strut, operating similarly, the plunger takes the form of a stepped piston-rod extending through both ends of the cylinder. As shown in Fig. 3, the cylinder space of the strut 8 is connected by a flexible conduit 12 to a rigid vessel 11 having within it a variable volume reservoir 11<SP>1</SP> which is preferably made of synthetic rubber and is filled with a gas, such as air or nitrogen, under pressure. The vessels 11 may be independent from each other but are preferably interconnected by a conduit 13 having filling and venting plugs 14. The initial pressure in the reservoirs 11<SP>1</SP> may be 450 lb./sq. in. and the initial pressure in the system may be raised during filling with liquid to 540-3,000 lb./sq. in. By increasing or decreasing the initial gas pressure in the reservoir 11<SP>1</SP>, the volume of the reservoirs under the initial hydraulic pressure is smaller or greater and the proportionate rise in pressure as the tool arms move out to accommodate bigger logs is correspondingly greater or smaller.