PURPOSE: To reduce the fatigue of operation by automatically returning an arm and a bucket to their original excavating attitudes only by the manual operation of the lowering and turning of a boom and the damping of a bucket bottom after discharging earth in an oil pressure excavator such as a loading shovel.
CONSTITUTION: When a bucket 4 is automatically returned to an original excavating location after discharging earth, a manual excavating attitude returning change- over switch 16 is changed over to a return position. Levers 13, 14, 15 are worked by manual operation, the damping of a bottom of the bucket 4 is closed and a boom 2 is lowered being turned up to an original excavating location. On the other hand, a control circuit 20 puts out controlling signals, an arm angle setter 30 and a bucket angle setter 31 put out signals in response to the output and a manual-automatic change-over switch 35 is changed ovre to contacts 36b, 37b. Deviation signals Δeβ, Δeγ between signals corresponding to present arm angle β and bucket angle γ put out from arm angle and bucket angle detectors 60, 61 and set signals ar added to oil pressure control valves 50, 51 through amplifiers 40, 41, and the lowering of an arm and damping are automatically controlled.
OOTSUKA KAZUO
NOGAMI SABUROU
IGARASHI MICHIAKI
HORIKOSHI TOSHIAKI
IZUMI KAZUHIRO
| JPS5264105A | 1977-05-27 |