GB1391413A - Agricultural implements - Google Patents

Abstract

1391413 Brakes actuated by over-running of driven shaft; full-face disc brakes INTERNATIONAL HARVESTER CO 10 Oct 1973 [10 Oct 1972] 47307/73 Addition to 1361330 Heading F2E An agricultural implement provided with a braking mechanism comprising a braking surface 240, Figs. 1, 3, a drive member 245 movable into engagement with the braking surface, and a driven member 212, the drive and driven members being so constructed and arranged that if, in use, the driven member overruns the drive member, the drive member 245 moves into engagement with the braking surface 240 and co-operates with the driven member to reduce its speed, is characterized in that the braking surface 240 forms part of a brake member 236 which is resiliently mounted, e.g. on a wave spring 235, Fig. 5, with respect to the drive member 245 so that the peak torsional stresses developed in the drive and driven members during braking are less than would occur in the absence of the resilient mounting. As shown, a frusto-conical drive member 245 has fixed (e.g. welded), to it a dust shield 250 and pulley sheaves 151, 252, together forming a drive assembly. When the pulley is driven in a direction which is counter-clockwise when viewed from below, the drive assembly climbs up a helical rib 241 on driven shaft 212 until the uppermost edge of drive member 245 abuts spacer 248, and eventually shaft 212 is driven through washer 244 secured by nut 243 to the shaft. When drive to the pulley 251, 252 is discontinued, the momentum of the cutting blade 223 causes shaft 212 to over-run the drive assembly, whereupon this assembly descends down the helical rib 241 until the conical braking surface 247 on member 245 engages conical surface 240 on brake member 236. Brake member 236 cannot rotate because of engagement of its lugs 237 with indentations 238, but it is forced down, causing deflection of wave spring 235. Initial engagement of the conical surfaces rapidly increases the speed difference between drive and driven members so the brake is self-energizing. A dust cover 253 held in sheave 252 by a spring strip 254 forms, with 0-ring seal 255, a lubricating-grease reservoir.