Document Type and Number:
Japanese Patent JPS57193782
Kind Code:
U
Abstract:
A pressure compensator installed in the bit body of a rotary earth boring tool to lubricate the bearing surfaces of a rotary cutter and to effect a liquid seal. In order to reduce the number of component parts and to enhance durability, the pressure compensator includes a rubber diaphragm interposed between upper and lower capsule halves that form a spherical space.
Application Number:
JP7849081U
Publication Date:
December 08, 1982
Filing Date:
May 29, 1981
Export Citation:
International Classes:
E21B10/24; E21B10/22; (IPC1-7): E21B10/22