Patent GB-713244-A (GB)
Title: Improvements relating to load lifting apparatus for a tractor
IPC: B66F9/065
Filed: 1949-12-20
Abstract: 713,244. Hedge cutters; hay-rakes. SMITH, W. H. March 20, 1951 [Dec. 20, 1949; July 5, 1950], Nos. 32622/49 and 16807/50. Classes 6 (2) and 6 (3). [Also in Groups X, XXI and XXX] An attachment for a tractor comprises a hollow upwardly-extending column mounted at its lower end on a tractor adjacent the rear axle, a hinged inner plunger rod longitudinally slidable within the column and projecting upwardly out of the top of the column and carrying a jib pivoted to the top of the plunger rod for rotation relative to the plunger rod about a transverse horizontal axis of support near one end of the jib, means for holding down that end of the jib so that upwardly-extending column mounted at its lower corresponding upward movement of the other end of the jib, and means for applying the power of the tractor engine directly or indirectly to the plunger rod at will to move it upwardly relatively to the casing, in which the jib is also rotatable relatively to the column about a vertical axis, and in which the said horizontal axis of support of the jib is so disposed in relation to the axes and dimensions of the jib and column as to permit the jib to be swung down into an upright storage position alongside the column with the plunger rod lowered and the holding down means released. As shown in Fig. 2, the pillar 11 comprises a thick outer casing 13 and an inner hydraulic cylinder 19 which, together with a head assembly 25, is manually rotatable within the casing 13, bearings 20, 21, 26 being provided to facilitate this movement. The jib is pivoted at one end to an adjustable strap 42 whilst the piston rod 16, slidable in cylinder 19, is operatively pivoted to the boom at 17; a pin 39 engageable with holes 40 in a sliding rod 37 allows the distance between these pivots to be adjusted. The jib has a pair of telescoping sections 31, 32 which are secured in the retracting position by a pin 34, and at the end of section 32 is carried a pulley 35 and an eye 36. By removing the pin 43, the jib can be pivoted to a stowed position parallel with the rod 16. In that position the jib can also be used for uprooting posts &c. In one modification (not shown) the rod 16 has a pair of trunnions which extend through slots in the pillar 11 and are connected through links to the power operated draft links of the tractor, operation of which effects movement of rod 16. In a further modification (also not shown) described in the first Provisional Specification, the jib is luffed by a cable secured thereto and passing through the centre of a pillar supporting the jib to a hydraulic ram arranged horizontally on the rear axle casing. In the second Provisional Specification, arrangements are described for slewing the jib by means of a mechanical coupling with either the draft links or the power take-off shaft on the tractor. The implements may be replaced by various load handling attachments (see Group XXX) and according to various further modifications described in the Provisional Specifications only, the implement may be replaced by a hay rake with or without a push-off mechanism, or a hedge cutting bar as described in Specification 686,548.