GB2030435A - A mower with cutter discs driven from underneath - Google Patents

Abstract

A rotary scythe mower has cutter discs 1 each driven from underneath by a shaft 33 and bevel gearing 85 including a bevel pinion 88 provided with a sleeve 89. A bore through the sleeve 89 has splines to mesh with splines 55 on the shaft 33. The pinion 88 is mounted in ball bearings 90 on the sheath 89. The disc casing 84 is sealed by a packing 93 on the end 94 of the sleeve 89. The packing 93 has lips to engage a plane surface of a casing wall part 92. The casing 84 includes a lower wall 91 which is protected by a skid 77 and which in the axial direction of the shaft 33 has an extent 1 smaller than the width L of the upper part of the casing 84. <IMAGE>

Description

SPECIFICATION A mower with cutter discs driven from underneath This invention relates to the structures of the disc casings of a mower having discs driven from underneath by means of a transmission shaft.

This shaft crosses each casing by passing through a sleeve connected to a bevel pinion which is intended to drive a bevel wheel connected to the disc placed above the said casing.

In order to ensure guidance of each pinion in association with its sleeve, two bearings for example of ball type are provided in each casing. One of these bearings extends on one side ofthetoothing of the said pinion while the other bearing extends on the other side of the said pinion. In order that such an assembly may be realised a disc casing must be provided which has quite large dimensions in its lower part. Now as each of these casings is fixed on the upper part of the mower housing, extending through the latter, the openings which must be formed therein are large and decrease the solidity of the said housing. These openings in fact create zones of lower strength in the housing, favouring the appearance of cracks.

Moreover the greater are the dimensions and consequently the volume of each disc casing, the larger are the quantities of lubricant which must be introduced into these casings. Furthermore the sleeve with which each of the pinions is connected must have a sufficient strength so that it may transmit the load to which it is subjected to the bearings of each disc casing. The dimensions of this sleeve therefore cannot be reduced below a certain minimum, which limits the reduction of the size and weight of each of the said casings.

The present invention permits of remedying the above indicated drawbacks and reducing the size of the disc casings, at least in their lower part. This permits of reducing the size of the openings provided in the mower housing, thus increasing its solidity. The quantities of lubricant necessary for the lubrication of the bevel gearings housed in the casings are also reduced.

It has been possible to obtain such results by virtue of the fact that the bearing elements of each pinion are situated on one side of the toothing of the said pinion, while the seal elements of each disc casing are lodged on the other side of the said toothing. These latter elements are in fact advan tageouslysituated on the side of the apex of the pitch cone of each bevel pinion and press upon a flat internal face of the casing. In accordance with the invention these seal elements are either mounted on the sleeve of each pinion or fixed directly on the pinion for example byvulcanisation or cementing.

As regards the bearing elements, in accordance with the invention they can be installed immediately behind the toothing of the pinion. Thus the length of the sleeve is reduced to the minimum. Moreover the splines provided inside the sleeve can be situated in accordance with the invention at the level of the bearing elements. Thus it is possible to reduce the thickness of the sleeve without danger of bursting, since the said sleeve is surrounded over substantially its entire length by the internal rings of the bearings.

The size of each disc casing is thus advantageously reduced so that the width of its lower part, measured in the direction in which the transmission shaft extends passing through the said casings, is less than the width of its upper part. The width of the lower part of each of the said casings is preferably less than or equal to half of the width of the upper part.

The invention will be explained in greater detail hereinafter, with further characteristics and advantages, in the following non-limitative description of an example of embodiment of the invention given with reference to the accompanying drawings, wherein:- Figure 1 represents a plan view of a mower according to the invention, Figure 2 represents a partial longitudinal section along ll-ll in Figure 2, Figure 3 represents a cross-section along Ill-Ill in Figure 1.

In the drawings, as represented in Figure 1 the disc mower according to the invention comprises discs 1, 2 of circular form. An element 3 offrusto-conical form, provided with ribs 4, is placed above the disc 2 situated at the free extremity of the cutter bar of the machine. This free extremity is likewise provided with a swath plate 5. The other extremity of the cutter bar is provided with a shoe 6 above which there extends a gear box 7. See for example co-pending Application No. 22053/78. This extremity is connected to a chassis (not shown) permitting the hitching of the said machine to a tractor (not shown) which is necessary for driving and displacing the machine in the direction of the arrow A. The discs 1 and 2 are each provided with two diametrically opposed blades 8.Each blade 8 is mounted on the discs 1,2with the aid of a screw 9 and a nut 10 recessed into a protective dished washer 11.

The discs 1,2 of the mower are intended to be driven in rotation by means of a shaft 12 substantially perpendicular to the plane of Figure 1, on which shaft they are fixed by a nut 13. Figure 1 likewise shows that the discs 1, 2 are disposed above a support plate 14 beneath which there at least partially extend transmission members. It will be noted that the rear edge 15 of this support plate 14 is substantially rectilinear while the leading edge 16 comprises circular sectors 17 concentric with each of the discs 1, 2, with the purpose of protecting the latter. These sectors 17 are of a diameter slightly greater than that of the discs 1,2 but clearly smaller than the diameter of the trajectory of the blades.

Each of the said discs 1,2 is driven in rotation with the aid of a bevel gearing lodged in a disc casing situated beneath the said discs 1,2. These bevel gearings are driven by a shaft set in motion by the grooved pulley 25 and through the intermediary of the gear box 7.

The disc casings 84 according to the invention, represented in detail in Figures 2 and 3, each contain a bevel gearing 85 driven in the same manner as the bevel gearings indicated above. The bevel gearing 85 comprises on the one hand a wheel 86 fast with the shaft 12 the upper part of which is provided with splines 40 intended to cooperate with those of the central part 44 of each disc 1, 2. The shaft 12 is guided with the aid of ball bearings 41 in the upper part 87 of the casing 84. The bevel gearing 85 further comprises a bevel pinion 88 through which the transmission shaft 33 passes. According to the invention this bevel pinion 88 is provided with a sleeve 89 extending on the side opposite to the side on which the apexes of the pitch cone of the pinion 88 extends.This sleeve 89 can either be made in one piece with the pinion 88 or can be fitted into the pinion 88 thus constituing a part separate from the pinion 88. Within the sleeve 89 there are provided splines cooperating with the splines 55 of the transmission shaft 33 for the purpose of driving the bevel gearing 85 and consequently each disc 1,2 in rotation.

In accordance with the invention the guidance of the pinion 88 is effected by means of ball bearings 90 situated on the side on which the sleeve 89 extends and fitted on the latter at the extremity of the lower part 91 of each disc casing 84. Thus the pinion 88 is guided in overhung manner. It is thus possible to reduce the strength of the sleeve 89 which does not have to transmit the load from one bearing to the other, as is the case in the form of embodiment of disc casings of mowers of known type. To this end the bearings 90 extend exclusively on one side of the toothing of the pinion 88, namely on the side opposite to that where the apex S of the pitch cone of the pinion 88 is situated. Furthermore they are provided with sealing devices in order to block one of the extremities of the lower part 91 of the disc casing 84.These bearings are moreover situated at the level of the splines of the sleeve 89 intended to cooperate with those of the shaft 33. Therefore the thickness of the sleeve can be reduced without risk of bursting, since the bearings are mounted without play on the said sleeve 89. Without departing from the scope of the present invention these bearings, which are of the ball type, can perfectly well be replaced by roller bearings or bearings of another type.

On the side where the apex S of the pitch cone of the pinion 88 extends, its toothing is situated in the immediate vicinity of the lower vertical wall 92 of the disc casing 84 which is pierced with a passage hole for the transmission shaft 33. The sealing of the disc casing 84 is effected here by a ring seal 93 fitted on the end 94 of the sleeve 89 towards the apex S of the pitch cone of the pinion 88. This seal 93 is provided with lips which press upon the internal flat face of the lower vertical wall 92 of the casing 84 which is protected in its lower part by a skid 77 fixed to the support plate 14 with the aid of screws 78 and 79 (Figure 3).

According to a variant of embodiment it is likewise possible to fix the seal 93, for example by cementing orvulcanisation, upon the face of the pinion facing the apex S of its pitch cone. It is then possible to eliminate the extremity 94 of the sleeve which protrudes on this side of the pinion 88.

The advantages deriving from the structure of the lower part 91 of the disc casing 84 are as follows:- By reason of its compactness, the opening necessary for the passage of the casing 84 through the supplementary plate 83 fixed to the support plate 14, especially by means of screws 78, is much smaller.

The mower housing, constituted by the plate 83 and the support plate 14, is thus substantially more rigid than the previously known mower housing. Moreoverthe internal volume of the disc casings 84 fixed on the support plate 14 with the aid of screws 58 is smaller than the volume of the disc casings of known type, which permits of reducing the quantity of lubricant necessary for the lubrication of the bevel gearings 85. In fact the width 1 of the lower part 91 of each disc casing 84, measured in the direction in which the transmission shaft 33 extends, is less than the width L of the upper part 87 of the said casing 84.

In the present example of embodiment the width 1 is even less then half of the width L.

Moreover the fact of the provision of a seal 93 cooperating with a flat surface permits of placing the transmission shaft 33 as close as possible to the bottom 95 of the upper part 87 of the disc casing 84, since the diameter of the passage hole of the shaft 33 is hardly larger than the diameter of the said shaft 33. This permits of reducing the height of the lower part 91 of the disc casing 84, which contributes to a reduction of the thickness of the mower, with the purpose of obtaining a low height of cutting of the fodder.

It is further quite apparent that various modifications, improvements or additions may be made to the present example of embodiment without thereby departing from the scope of the present invention.

Claims (8)

1. A mower with cutter discs driven from underneath, comprising for the purpose of driving its discs bevel pinions driven by a transmission shaft and meshing with bevel wheels respectively connected to each of the discs, each bevel gearing constituted by a wheel and a pinion each guided by bearing elements being housed in a sealed casing through which the said transmission shaft passes, characterised in that the bearing elements (90) of each pinion (88) are situated on one side of its toothing while the seal elements (93) are situated on the other side of the said toothing.

2. A mower according to Claim 1, characterised in that the seal elements (93) are situated on the side of the apex (S) of the pitch cone of each pinion (88).

3. A mower according to Claim 1 or 2, characterised in that the said seal elements (93) press upon one of the internal faces of the casing (84).

4. A mower according to Claim 3, characterised in that the said face is flat.

5. A mower according to any one of the preceding Claims, characterised in that the seal elements (93) are mounted on a sleeve (89) of the pinion (88).

6. A mower according to any one of Claims 1 to 4, characterised in that the seal elements (93) are directly fixed upon the pinion (88).

7. A mower according to any one of the preceding Claims, characterised in that the width (1) of the lower part (91) of the disc casing (84), measured in the direction in which the transmission shaft (33) passing through the said casing (84) extends, is less than the width (L) of the upper part (87) of this casing (84).

8. A mower according to Claim 7, characterised in that the width of the lower part (91) of each casing (84) is less than or equal to half of the width of its upper part (87).