GB1393456A - Mole plough supporting linkages - Google Patents

Abstract

1393456 Mole plough; tractor links HUDSWELL YATES DEVELOPMENTS Ltd 31 May 1973 [2 June 1972[ 25972/72 Headings A1B and A1P [Also in Division F2] A linkage for coupling a tractor to a mole plough such that the plough operates at an equilibrium working depth with respect to the tractor includes first and second interconnected members which are relatively vertically movable with respect to each other so as to restore the plough to its correct depth. The members are constrained in their movement by at least one pair of upper and lower sector shaped cams 36, 38 whose curved surfaces follow respective arcuate tracks 32, 33 formed by one of the members. In one form the first member comprises a cage like guide link 26 which forms part of a quadrilateral tractor coupling arrangement. Within the link 26 is located a floating box 30, that forms the second member which adjustably receives a coulter blade 16 to which the mole is connected. The blade is positioned within the box by adjustable studs (34) and pin (35) Fig. 5 (not shown). The box 30 has stub shafts 40 upon which upper and lower pairs of sector shaped cams 36, 38 are pivoted. The cams ride on the curved inner surfaces of the guide link 26 and are prevented from dropping under zero or low load by pins 42. Ram 48 holds the guide link 26 stationary with respect to the tractor such that an elevation of the tractor causes the cams to rotate anticlockwise. The resultant forces upon the stub shafts 40 exert a turning moment upon the blade 16 and cause it to raise the leading end of the mole. As the mole rises, relative movement between the blade 16 and guide link 26 is reversed such that the cams rotate clockwise. The cams are arranged such they are at the centre of their permitted rotational movement, and the geometric centre of curvature of the guide links curved surfaces corresponds to the apparent hitch point of the mole plough. Removal or introduction of the mole is accomplished by the ram 48 moving guide link 26 to an extreme upper or lower position. In a modification, Figs. 7-9 (not shown) the box 30 is mounted on the coulter blade and has forwardly projecting parallel faces which engage the opposed faces of a rectangular frame that replaces the cage like guide 26. One upper, and one lower sector shaped cam are mounted on stub shafts which extend between the plates and engage the opposed curved surfaces defined by the frame opening.