GB1349813A - Rotary mowing machines - Google Patents

Abstract

1349813 Lawn mowers MASON & PORTER Ltd 21 April 1972 [6 July 1971] 18618/72 Heading A1F The cutting height of a power driven lawn mower is adjusted by a manually operable lever linkage interconnecting the front and rear ground wheels without obstructing the grass cuttings discharge chute 3 in the mower's housing 2. In one embodiment (Fig. 1) each front wheel 6 is mounted on a stub axle 8 at one apex of a triangular plate 7 whose lowest apex is rigidly connected to its counterpart by a transverse rod 30 pivotally mounted in the front of the housing. The other apex of one of the plates 7 is connected by a rod 9 to a crank 29 linked to a transverse rod 16 interconnecting the mountings of the two rear wheels. Each mounting comprises an oblique 'T-shaped' member 10 which has a stub axle 13 for the respective ground wheel and is rotatably mounted via aperture 12 and sleeve 28 to the housing 2. The cutting height is altered by a lever 17 riveted to one of the members 10 and having a detent 18 which engages a range of apertures 19 in an associated plate 20, adjustably secured by bolts 23 to the housing. To facilitate height adjustment the mower's weight acting on lever 17 is counterbalanced by a spring 24 which is connected at one end to the housing and at the other to either the associated member 10 or to the transverse rod 16 (not shown). The geometry of the linkage is such that each interval in the range of apertured settings 19 produces a small increment in height when the cutter is near the ground and a larger increment at more elevated levels, and may be such that either the housing 2 remains horizontal throughout the various settings and slopes forwardly at some of the settings. In alternative embodiments the T-shaped members 10 may be replaced by triangular elements and the pivot point 28 may be raised with respect to the wheel axle.