Mowing machines

#THIS INVENTION relates to mowing machines.

#More particularly, the invention relates to mowing machines of the kind comprising a frame adapted to be mounted on a tractor three-point linkage, and a plurality of cutting units connected to the frame, including at least two laterally spaced side cutting units and a center cutting unit positioned so as, in use, to cut the swath between the two swaths cut by the side cutting units.

#It is desirable that in use of such a machine the pressures exerted on the ground by each of the cutting units should be reasonably equal to that exerted by the other units. This is usually achieved in known machines by mounting each unit on the end of a support arm pivoted to the frame, so that the pressure of each unit on the ground is due to the weight of the unit alone, the weight of the frame being borne by the tractor. It is also usual to spring bias each unit upwards to relieve some of the weight of the unit from the ground. The mounting of the cutting units makes these known machines relatively complicated and also heavy.

#The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

#FIG. 1 is a side elevation of a mowing machine according to the invention,

#FIG. 2 is a rear elevation of the machine of FIG. 1,

#Referring to FIGS. 1 to 3, a mowing machine comprises a frame 10 adapted to be mounted on the three-point linkage of a tractor, and two side cutting units 30 and a center cutting unit 32 carried on the frame 10.

#The frame 10 comprises an A-frame 12 having two side members 14 fixed at the upper ends to a link member 16 adapted to be connected to the tractor top link 86 (FIG. 4) and at their lower ends to a transversely extending box-section frame member 18. Two link members 20 fixed to the frame member 18 provide points of attachment to the tractor lower arms 82.

#Fixed to the transverse frame member 18 near its mid-point are two rearwardly extending frame members 22. A pair of reinforcing struts 24 extend between rear end portions 26 of the frame members 22 and the upper part of the A-frame 12, to make the structure rigid and assist accurate location of the rear ends of the frame members 22 during assembly. A mounting arm 34 for the center cutting unit 32 extends between the rear ends of the rearwardly extending frame members 22 and is mounted on them by means of a ball joint 36 between their rear end portions 26. As shown in FIG. 9, the ball-joint 36 comprises a spherical bearing member 361 fixed by a suitable adhesive to a sleeve 362 secured between the frame members 22 and struts 24 by means of a bolt 363, and a complementary bearing member 364 fixed to the mounting arm 34. The mounting arm 34 extends forwards from the ball joint 36 and projects through a generally square aperture 40 in a plate 38 fixed to the transverse frame member 18. The plate 38 is positioned between the forward ends of the rearwardly extending frame members 22 which are accordingly spaced apart a greater distance than their rear end portions 26, being joined to them by angled portions 28. The aperture 40 has two vertical side edges 42 which limit the lateral movement of the mounting arm 34 as described below. The upper edge 44 of the aperture 40 is in the shape of a shallow inverted "V", at the apex of which is an upwardly extending slot 46 shaped to receive the upper edge of the mounting arm 34.