| 摘要 |
A trenching apparatus is disclosed which has a vehicle having a power train comprising at least an engine, transmission and power output shaft from said transmission; a motive system for moving the vehicle; an adjustable boom assembly attached to the vehicle; a cutting wheel rotatably attached to the boom assembly; and drive means connecting the cutting wheel to the power train for causing the cutting wheel to rotate. The improvement lies in a torsional limiting device connected between the power train and the drive means, the device comprising a planetary ring gear assembly having a sun gear jounaled in the device, a planet gear rotatable on a planet carrier journaled in the device, the planet gear rotatable on the planet carrier, interposed between and in geared relationship with the sun gear and a ring gear which is journaled in the device, the sun gear attached to the power output shaft from the transmission and the planet carrier attached to the drive means a plurality of friction discs are movably keyed to the ring gear such that rotation of the ring gear causes the friction discs to rotate a plurality of reaction plates are movably keyed to the device, each reaction plate being sandwiched between two said friction discs and piston means are attached to the device for forcing the friction disc and reaction plates together under force. |
