| 摘要 |
The leg has a base and telescopic legs, 7, 8, 14, 15 of a laminated plastics material. The telescopic legs of the invention are made to desired tolerances whereby machining by conventional methods is avoided. The device of the invention avoids ignition problems and is less hazardous. Furthermore, the device has good strength and low water absorbence and thus does not swell and seize in use. A detachable head piece is fitted around the base leg 7 and sealed by O-rings, an end plug 3 being sealed and held in the base leg by a gearbox adaptor plate bolted to the head piece. <IMAGE> |
