GB817828A - Improvements in or relating to track attachments for tractors - Google Patents

Abstract

817,828. Endless track vehicles. MASSEY-FERGUSON (GREAT BRITAIN) Ltd. Oct. 20, 1955 [Nov. 2, 1954; April 1, 1955; July 22, 1955], Nos. 31672/54, 9532/55, and 21213/55. Class 79(1) A tractor has an endless track attachment comprising an arm 7 carrying an idler wheel 6, round which, and round the associated driving ground wheel 1 of the tractor, an endless track 8 is fitted, the arm 7 being mounted on the tractor so as to be capable of moving the idler wheel both forwardly and towards the ground. As shown in Fig. 1 the arm 7 carries the idler wheel 6 at its forward end, and is pivotally connected at its rearward end to one end of a link 20 pivotally connected at its other end to the tractor axle assembly at 22. Bolted to the latter assembly is a bracket 27 having three pivot pin connection apertures 27a, 27b, and 27c, which form alternative attachment points for a telescopic spring unit 35, the other end of which is attached to one end of a link 30. The other end of the link 30 is pivotally connected at 31 to a pair of lugs 29 rigid with the arm 7. When a single compression spring unit 35 is employed (Fig. 6, not shown), one of the attachment apertures 27a, 27b, 27c may be selected in accordance with the degree of inclination of the line of action of the spring unit desired. As shown, however, a second spring unit 35a is employed, and in this case the unit 35 is connected to the aperture 27a, and the apertures 27b, and 27c are used for mounting a bracket 53 forming the upper attachment of the unit 35a. The upper end of the unit 35a is connected to the bracket 53 via a link 30a which is similar to the link 30. The lower end of the unit 35a is connected to the junction of a pair of links 57, 60, the other ends of which are connected respectively to the pivot of the unit 35 with the link 30, and a pivot pin 45 carried by the lugs 29. In normal operation of the tractor, the parts are disposed as shown in Fig. 3. When it is desired to remove the track 8 from the wheels 1 and 6, a spanner is used as shown in dot-dash lines in Fig. 1, to apply a force to the pivot pin 42 between the lower end of the unit 35 and the link 30 to turn the link and unit through a dead-centre position to the position shown in Fig. 1. The unit 35 is then able to expand until a stop 44 on the unit engages an abutment 33 to prevent its further extension. The unit 35a and the link 31a are similarly turned through a dead-centre position, and it is then possible to move the arm 7 rearwardly so as to decrease the distance between the centres of the wheels 1 and 6 and so remove the tracks 8. Alternatively, where a single unit 35 is employed (Fig. 6, not shown), the arm 7 may be drawn rearwardly against the action of the unit 35. This may be effected mechanically by providing a lug on the lower surface of the arm 7 which may thus be connected by a chain to part of the vehicle power-lift mechanism. The track 8 comprises two fabric-reinforced rubber bands 9 (Fig. 5) which are prestretched in manufacture. The bands 9 are interconnected by cross members 10 having inwardly directed projections 11 adapted to engage between the usual lugs on the tracfor tyre treads. The track of the wheels 6 is variable by interposing spacing blocks and by reversing the wheels, each of which has an attachment flange disposed out of the plane of symmetry of the wheel (Fig. 2, not shown).