GB294379A - Improvements in trench digging machines - Google Patents

Abstract

294,379. Marks, E. C. R., (Harnischfeger Corporation). July 26, 1927. Endless-chain machines; digging apparatus.-A trench digging machine of the bucket ladder type has on one or both sides of the ladder means for widening the trench comprising digging apparatus supported from the ladder by means adapted to give the apparatus movement longitudinally of the ladder. The bucket ladder 10 is pivoted about the shaft 12 from which the bucket chain is driven. Shafts 24, 28 pass transversely through the ladder, intermediately and at the lower end thereof respectively, and carry cranks 26, 30, the crank pins supporting bearing members 34, 35 connected by spaced pairs of bars 36; depending U-shaped brackets connected to the bars carry digging teeth 38 while on the outer side of the outer bars 36 side trimming cutters are provided which comprise shanks 43 with inclined blades 44 which direct the soil to the centre of the trench. An additional U-bracket, with teeth 38 and side cuttar, is provided on the outer side of the bearing members 34 as shown in Fig. 10, while a similar arrangement is provided on the bearing members 35 but in the latter case the U-bracket is placed longitudinally of the ladder as indicated in Fig. 1. The widening apparatus is driven from the shaft 12 through a chain 53 held away from the bucket chain by an idler pulley 55 carried by pivoted arms 57, the movement of the latter being limited by threaded members 59. The cranks 30 may be longer than the cranks 26, whereby the lower ends of the digging apparatus receive a rocking motion. Further, the pins of the cranks 26 may be so arranged that the lateral displacement of the upper ends of the digging apparatus is greater than that of the lower ends, whereby the trench is formed with sloping sides. Also, the cranks of each pair may be angularly offset to ensure their passage past the dead centre.