GB863673A - Improvements relating to trench excavators - Google Patents

Abstract

863,673. Digging trenches. CLEVELAND TRENCHER CO. March 4,1960, No. 7765/60. Class 68(1). A trench excavator comprises a ladder type digging unit 10 supported on a tractor frame by pivoted yoke arms 8, 9 which are operable to swing the unit upwardly into a substantially horizontal roading position, or to lower it into a diagonal operative position, the length of the digging unit being kept to a minimum by arranging a transfer conveyer 13 between the discharge end of the digger conveyer and the feed end of the unloading conveyer 11. The yoke arms 8, 9 are hinged to a rigid mast 7 and are actuated by fluid pressure cylinders 53. The arms of the yoke 9 have slotted extentions 22, pins 58 on the unit 10 slidable in the slots being connected to the rams of fluid pressure cylinders 56 on the arms of the yoke. Normally whilst digging, the cylinders 56 are fully retracted and the stresses are relieved from the cylinders and rams by a pivoted distance piece which is manually insertable in the slots. If it is desired to alter the slope of the unit 10 whilst digging, the distance pieces are swung out of the slots and pressure is admitted to the cylinders, and the same procedure is preliminarily adopted when the unit is to be removed from the trench, the bite of the digger into the ground being thus broken to facilitate the upward swing by the cylinders 53. The boom of the unit 10 is of conventional telescopic type, the parts 24, 24a being loaded by springs 25 and the end sprockets 36 being carried on a member which is slidably adjustable in the boom part 24 to enable the effective length of the boom to be altered. Wobble between the parts 24, 24a is prevented by clamping means 42 at the junction point of the parts. The digging conveyer is driven by a motor 4, power take-off 5, and chains and sprockets 32, 31, 30, and the buckets 28 are cleared by scrapers 34a, 34b which are revoluble on the shaft 19 but are held by a ratchet 35 having a spring-pressed pawl which yields if the scraper 34a cannot clear the bucket. In this case, the scraper 34a travels around the shaft 19 with the bucket, until the scraper 34b is in the scraping position in which it is again held by the ratchet. A pump 6 for supplying the hydraulic pressure system, is driven by the motor 4, and the transfer conveyer 13 is driven by a fluid motor connected with the shaft 66a, the material being dumped into a receiver 68 on the unloading conveyer 11. An upwardly pivotable baffle 67 directs the material into the receiver 68, and the lower end of the conveyer is guarded by a member 69. Deflecting plates 74 which may be swung up, as in Fig. 1, to inoperative position about the shaft 72 are adjustable along the shaft, according to trench width, and act to direct material inadvertently falling from the conveyer 13 back into the trench. The unloading conveyer 11 is pivotable, through 180 degrees, on a vertical axis 92 by an hydraulic cylinder 90 and linkwork 93. The conveyer 11 also is in two parts which are hinged together at 87 so that the outer part 86 may be folded upwardly to permit the trencher to pass obstructions such as trees. The folding is effected by an hydraulic cylinder 88. The outer part 86 may also move slightly downward from alignment with the other part, if the height of the receiving truck necessitates this.