Patent GB-850194-A (GB)
Title: Improvements in or relating to hedge trimming and like machines
IPC: A01D34/86
Filed: 1957-09-20
Abstract: 850,194. Hedge-cutters ; mowing machines. BANFIELD, R., and CAMERON, C. St. C. Oct. 3, 1958 [Sept. 20, 1957], No. 29728/57. Classes 6(2) and 6(3). In a hedge trimmer of the kind comprising an elongated cutter mounted, so as to be adjustable about a horizontal axis, at one end of a supporting arm which is attached at its other end to a traction vehicle, the supporting arm comprises two parts which are hinged together, spring means being provided for resisting the relative movement of the two parts. In the embodiment shown in Figs. 1 and 2, the cutter 20 is pivoted to a mounting member 16 supported in one part 15 of the two-part, tubular supporting arm 14, 15, the supporting arm being attached at one end of the lift links of a tractor 10. Adjustment of the cutter 20 is effected by means of a twopart rod 22, 36, connected to an adjusting mechanism 8 on the tractor. The parts 14, 15 of the supporting arm are secured to hinge plates 23, 24 respectively, the said plates being hinged together at 25 so that relative movement between the parts 14 and 15 about a vertical axis may take place in the event of the cutter's hitting an obstruction, such movement being limited by a pin 33 welded to the flange 23 and fitting loosely in bores in both flanges, and being opposed by springs 30 whose tensions may be adjusted. The plate 23 is connected to a clutch on the tractor so that the drive to the cutter is disconnected when the plates 23 and 24 move apart. As shown in Fig. 4, the connection between the two parts 14 and 15 is modified so that the parts may pivot relatively to each other about a vertical axis, and may also rotate relatively to each other, about their longitudinal axis. The part 14 of the supporting arm is formed with a flange 40 to which is welded two triangular plates 41, one above and one below the arm. The part 15 is supported by the limbs of a clutch member 50 secured between the plates 41, and by telescopic links 64 pivoted between the forke ends of a bracket 58 mounted on the plates 41, and between brackets 61 secured to the part 15. The plates also support a hinge pin 43 surrounded by a bearing which is integral with a plate 46 formed with a spigot 48 for engagement in the end of the part 15. As the cutter encounters an obstruction, and depending on the position of the cutter relative to its supporting arm, the part 15 can either pivot about the pin 43 or, by virtue of the presence of the telescopic links 64, rotate, relative to the part 14 about its longitudinal axis both movements being opposed by an adjustable tension spring 53. As shown in Fig. 6 the part 14 is provided with a cam 69 formed with four tracks 92 for cam followers 80 equispaced on the part 15, the cam and followers being urged into engagement by a compression spring 75. The arrangement in this case is such that the part 15 can either pivot about the spindle 77, which is normally vertical, or can rotate relative to the part 14 about its longitudinal axis, in which case the cam followers run along the cam tracks. In either instance, a certain amount of longitudinal movement of the part 15 towards the part 14 results, this being resisted by the spring 75. As disclosed in the Provisional Specification, the arrangement shown in Fig. 1, may be applied to a grass-cutting machine.