PURPOSE: To make it possible to use effectively a hydraulic pump for boring operation in a hydraulic supply and discharge system in addition to the hydraulic pump for traveling in a hydraulic supply and discharge system in the case a crawler drill is made to drive straightly at a high speed.
CONSTITUTION: An acceleration controller of a crawler drill is equipped with a traveling hydraulic supply and discharge course 14 having hydraulic actuators 62 and 65 driving forward and reverse right and left crawlers 3 and 4 arranged to both sides of a car 2 and hydraulic pumps 63 and 66 and a boring hydraulic supply and discharge course 60 having a hydraulic actuator 68 operating a boring mechanism 6 and a hydraulic pump 69. Both hydraulic supply and discharge courses 14 and 60 are connected through a linking course 61, and a control valve 70 is provided to the linking course 61. When the hydraulic actuators 62 and 65 of the traveling hydraulic supply and discharge drive forward the right and left crawlers 3 and 4 at the same speed, the control valve 70 is opened.
SHIMOURA KENICHI
HASHI TAKAAKI
NABCO LTD