GB1420872A - Reversible plough mechanism - Google Patents

Abstract

1420872 Reversible plough mechanisms INTERNATIONAL HARVESTER CO 20 Feb 1973 [25 Feb 1972] 8300/73 Heading A1B A forecarriage unit 6 is mounted on the three-point hitch of a tractor and pivotally supports a shaft 3 fixed to a reversible portion 2 of a roll-over plough, a crank member 26 on the portion 2 being pivoted either directly at 40 (Fig. 3) or via a crank arm 131 (Fig. 8) to a double-acting jack 24, which itself is pivoted either via a crank arm 31 (Fig. 3) or directly at 143 (Fig. 8) to a mast 7 fixed to the forecarriage unit 6, a tension spring 37 (Fig. 3) or compression spring 138 (Fig. 8) acting to move th crank arm 31 or 131 toward's one or the other of two stops 35, 36 (Fig. 3) or 135, 136 (Fig. 8) so that the jack 24 is moved through its dead-centre position. The jack 24 may be reversed end for end, and the cylinder may be pivoted at its other end or intermediate its ends. A stop 18 on the forecarriage unit 6 is engaged by either of two dogs 16, 17 to define the two working positions of the plough. A pin 45 is pivoted on the crank member 26 and biassed to the vertical by a counterweight 49 so as to engage a notch 46 in the forecarriage unit 6 when the jack 24 is in its dead centre position to prevent back-swing of the portion 2. Operation (Fig. 3): Retraction of the jack 24 allows the tension spring 37 to move the crank arm 31 anticlockwise against the stop 35 and then rotates the crank member 26 until the axes of the pin 40, the shaft 3, and the spindle 29 lie in the same plane. At this moment, the jack 24 is fully retracted and the pin 45 engages the notch 46. Extension of the jack 24 causes the crank arm 31 to move clockwise away from the stop 35 until the axes of the shaft 3, the shaft 32 and the spindle 39 are in the same plane, and the jack 24 has passed through the dead-centre position. Operation (Fig. 8): Retraction of the jack 24 allows the compression spring 138 to swing the jack 24 clockwise about spindle 143 so swinging the crank arm 131 clockwise about its pivot pin 40 on the crank member 26 until its lug 135 abuts stud 137 on the crank member 26. Continued retraction of the jack 24 rotates the crank member 26 until spindle 143, pin 132, and shaft 3 are in the same plane. The jack 24 is in the fully retracted position and the pin 45 engages the notch 46. Extension of the jack 24 pivots the crank arm 131 anticlockwise about pin 40 until the spindle 143, pin 132 and pin 40 are in the same plane, and the jack 24 has passed through the dead-centre position.