GB747554A - Improvements in or relating to trenching machines - Google Patents

Abstract

747,554. Earth - excavating apparatus. HOWLETT, C. W. Nov. 30, 1953 [Nov 28. 1952], No. 30231/52. Class 68(1) In a trench excavator, the excavator bucket is mounted on a telescopic boom 15, 16 having a universal pivotal connection with a telescopic member 13, 14 extending transversely of a tractor-drawn wheeled frame 10. Filling of the bucket is accomplished either by advancing the frame 10, or by telescoping the boom 15, 16 on winding on to a winch drum 21 a cable 20 connected to the part 16. The winding on to a winch drum 25 of a cable 22, extending over a pulley 24 at the top of an upright post 23 to the bucket results in the boom rising vertically and then slewing sideways as the boom rides along a guide 33. The guide 33 is secured to the frame 10 and to a member 34, secured to and extending laterally of the frame. Towards the end of the slewing movement of the boom a further cable 26, attached to the cable 22, is tensioned and rocks arms 27 mounted about the axis of pivotal connection of the bucket to the boom. A pin extending between the arms 27 and engaging a cam slot in an arm 28 is thus caused to move the arm to withdraw a catch, preventing rotation of the bucket with respect to the boom, and the bucket empties. In another embodiment the boom is connected by an adjustable tie rod to an upright on the frame and the movement of the upright about a pivotal connection to the frame causes the motion of the boom along the guide member and may also cause the telescoping of the boom. Specification 575,701, [Group I], is referred to.