GB427120A - Improvements in or relating to machines for cutting grass - Google Patents

Abstract

427,120. Mowing-machines. COCKBURN, D. H., Rhodora, Richings Way, Iver, Buckinghamshire. Oct. 24, 1933, No. 29463. [Classes 6 (ii) and 6 (iii)] [See also Group XXVII] In a grass-cutter comprising a casing provided at its lower part with a combined cutting-rotor and air-impeller adapted to rotate in a plane parallel to the ground surface, the casing is supported on one or more front wheels or rollers 14 and a rear wheel 18 at each side, and is provided with a flange or shoe 43 at each side projecting slightly downwardly to prevent the machine from cutting into uneven or undulating surfaces. The casing 13 has its interior formed as a circular passage the cross-sectional area of which increases progressively in a circumferential direction, the part of greatest cross-sectional area being connected to a receptacle 24 for collecting the cut grass. The combined cutter and impeller 10 may be mounted in the open lower part of the casing 13 directly on the crank shaft of an engine 12. The front wheels 14 are vertically adjustable and the rear wheels 18 are mounted on handle-bars 19 adjustable about pivots for raising and lowering the rear part of the casing 13. A roller may be mounted between the wheels on extensions of the handle-bars. The wheel track is not greater than the width of cut, and the lowest part of the roller is slightly higher than the lowest part of the wheels 18. The receptacle 24 may be made of wire mesh or perforated material. An aperture 25 in the casing 13 is provided with a deflector 26 to direct some of the impelled air on to the engine cylinder 27 for cooling purposes. A part 28 of the casing 13 is partitioned off, provided with a lid 48 and fitted with baffle plates 29 to form an exhaust silencer, the gases from the engine entering through a port 30 and escaping through an aperture in the side of the casing. The integral blades 11 of the impeller 10 are provided with reversible cutters 33 secured by bolts 34. In a modification circular or square cutters are each adjustably secured by a single bolt. The cutters are constituted by small plates chamfered around their edges on the underside. A protecting shield or grid may be provided beneath the impeller. An electric motor may be employed for driving the impeller. Two impellers may be mounted side by side in one machine and may be driven from the same or different engines. They may be driven so that their front parts rotate towards or away from one another, the casing being correspondingly shaped. One impeller may be in advance of another, and the grass may be cut in stages. The Provisional Specification refers to Specification 385,473 and states that the centres of gravity of the blades may be disposed above the level of the point of fixing to the driving shaft so that the tendency is for the blades to be deflected downwardly as the speed of rotation increases.