WO1999055138A1

WO1999055138A1 - Mowing machine

Info

Publication number: WO1999055138A1
Application number: PCT/GB1999/001294
Authority: WO
Inventors: Keith Broomhall
Original assignee: Keith Broomhall
Priority date: 1998-04-29
Filing date: 1999-04-26
Publication date: 1999-11-04
Also published as: GB9808999D0; AU3718199A

Abstract

A mowing machine includes a rotatable driven shaft (18) on which are mounted flail cutting element (23), the flail elements being pivotal in relation to the shaft. The cutting elements are spaced apart in the axial direction of the shaft. The shaft is mounted on the machine so that its axis is at an acute angle to the direction of travel of a machine over the ground. Although the optimum acute angle is 45° to the direction of travel it may be in the range 30°-65°.

Description

MOWING MACHINE

This invention relates to mowing machines and in particular, but not exclusively, to mowing machines for agricultural purposes.

Mowing machines for agricultural purposes are used for cutting grass for forage. They are usually drawn behind a tractor and powered by the tractor to cut the grass into swathes to be subsequently picked up by a forage harvester, bailer or other machine.

Usually agricultural mowers have been of the disc mower type which comprises a row of discs, each carrying cutting knives, and which are rotatable about vertical axes to cut the grass. Such mowers are relatively complicated since drive must be communicated to each of the discs.

Flail mowers are also known but are not favoured for agricultural purposes because of uneven cut and other problems.

An object of the invention is to employ the flail mower principle in a manner making it more suitable for harvesting grass and similar crops.

According to the invention a mowing machine comprises a rotatable driven shaft, flail cutting elements mounted on the shaft for rotation therewith and spaced apart in the axial direction of the shaft, and a mounting for the shaft arranged so that in use the axis of the shaft is locatable at an acute angle in the range 30 ° - 65 °to the direction of travel of the machine over the ground.

Preferably the acute angle is at 40 °- 50 ° to the direction of travel. In a particularly preferable arrangement the acute angle is at about 45° to the direction of travel. The shaft usually comprises a plurality of flanges mounted on the shaft to lie at a right-angle to the axis of the shaft and spaced apart from each other along the shaft. The flanges each carry at least one flail cutting element pivotally mounted on the associated flange and having a radially outwardly located cutting portion.

Usually the cutting elements are of generally L-shape, one limb of the L being pivotally attached to the associated flange, and the other limb of the L constituting the cutting portion.

The machine may be arranged to be mounted on a tractor three point linkage during cutting with the shaft driven by the tractor power take off. Conveniently the machine is offset from the tractor to one side of the direction of travel of the tractor. The inclination of the axis of the driven shaft to the direction of travel may be such that the shaft is inclined at said acute angle in the forwards or rearwards direction with respect to the direction of travel.

The length of the shaft, the spacing apart of the flanges, the radius of rotation of the cutting elements, and the cutting width of the elements are each selected according to said acute angle, the required width of cut of the machine, the maximum height of the mown material (stubble height), the power available and other parameters.

At the preferred acute angle of 45° the rotational diameter of the cutting elements may be some 600mm but the diameter may be in the range 250-1, 000mm. The maximum stubble height may be some 80mm and the cutting width per flange may be around 300mm. For a rotor length of around 6,400mm there may be some twenty-two flanges equally spaced along the rotor shaft.

By having the shaft inclined at an acute angle to the direction of travel the cutting elements effect an elliptical cutting profile when viewed in the direction of travel. The axially spaced flanges result in an overlapping of each cutting profile producing a nearly flat surface of out crop. Power is reduced considerably compared with a conventional flail mower lying at 90° to the direction of travel. Preferably the flanges are circular when viewed in a direction along the axis of the shaft. The machine may be wheel mounted and the position of the wheels may be adjustable to change the cutting height of the machine.

Further features of the invention will appear from the following description of an embodiment of the invention given by way of example only and with reference to the drawings, in which:

Fig 1 is a plan view of a mowing machine according to the invention,

Fig 2 is a schematic plan view showing a rotor arrangement for the mowing machine,

Fig 3A shows an alternative cutting flail arrangement,

Fig 3B shows a front view of the cutting flail of Fig 3 A,

Fig 3C shows a side view of the cutting flail of Fig 3 A,

Fig 4 shows a diagrammatic end view of the rotor of the mowing machine,

Fig 5 shows a diagrammatic plan view, and

Fig 6 shows a further diagrammatic plan view.

Referring to the drawings a mowing machine is shown which is intended for agricultural use in cutting forage or other crops. It is intended for mounting behind a tractor on either the three point linkage, or a drawbar (in the case of a trailed machine), of a tractor to be driven by the tractor in conventional manner. In the illustrated version the machine is intended to be mounted offset to the side of the tractor having regard to the direction of travel. It may take up a position to one side or other of the tractor with respect to the direction of travel. The mowing machine comprises a main frame 10 which in normal use is supported with respect to the ground over which it travels by wheels 11 and 12 located towards opposite ends of the frame 10, the wheels being adjustable to space the machine at the desired height in relation to the ground which, in turn, determines the depth of cut. Power is transmitted to the machine through a drive shaft 13 which may adopt the position shown in full lines in Fig 1 or the position shown in chain lines. Drive is transmitted to a gearbox 14 which transmits drive through a shaft 15 to a side drive arrangement 16 and to a rotor shaft 18 mounted for rotation and supported at its ends on the frame 10. As shown in Fig 1 material cut by the machine may pass rearwardly onto a conveyor 19 which transports the cut material in the longitudinal direction of the shaft 18 towards one end of the machine whereby to form a swath 20 of the cut material. The conveyor 19 may be of any convenient form and may be a belt conveyor. Alternatively the cut material may be deposited directly on the ground in a full width swath, omitting the conveyor, or after moving the conveyor away from the material flow.

The shaft 18 carries a plurality of flanges 22 in the form of annular discs fitted to the shaft 19 in conventional manner. The flanges 22 are equally spaced from one another along the shaft 18 and, as illustrated in Fig 2, each carry two cutting elements 23 oppositely located about the flange 22. The cutting elements 23 are in the form of flail cutting elements being mounted on the associated flange 22 pivotally about a pivot axis 24. Each element 23 is in the form of an L-shaped member, the longer limb 23 A of the L being attached to the flange 22 and the shorter limb of the L providing the cutting blade 25. Figs 3 A, 3B and 3C illustrate a preferred embodiment of the elements 23 and it will be seen that there is a chamfered portion 26 on the cutting edge of the blade 25. Fig 3 A also shows the securing means 27 by which the elements 23 are pivotally attached to the flange 22. More cutting elements 23 may be mounted on each flange 22, equi-spaced about the axis, if required.

As can be seen from the drawings the rotor 18 extends at an acute angle 0. with respect to the

direction of travel D of the machine over the ground. As will be explained the angle & may be between 30°- 65° but is preferably 40° - 50°. The optimum angle Oi is about 45°.

The pivoting of the elements 23 about the flange 22 permits the elements to swing away on encountering an obstruction and the flange 22 can roll over any obstruction.

By angling the axis of the rotor at the angle 0C an elliptical cutting profile of the cutting elements 23 is achieved, when viewed in the direction of travel. The spacing of the flanges 22 results in an overlap in each cutting profile of the cutting blade 25 and a substantially flat cut surface of the crop is produced. Each of the cutting elements 23 has a cutting profile produced by a small width of the cutting portion 25 which reduces the power requirement compared with conventional flail cutters in which the angle of the rotor to the direction of travel is 90°.

It will be appreciated that the mower may be operated in one of two modes, either with the mower inclined to the direction of travel in a trailing direction or in a leading direction.

In identifying the value of the angle 0. there are several variable parameters which may be

employed. In determining the angle 0. these parameters include, with reference to Figs 4, 5 and 6, the following:

C_EFF maximum effective cutting width for rotor flange

C_P cutting profile of the flange mounted cutting blades

S the maximum practical stubble height

C_w the cutting width per flange

F_s the flange spacing longitudinally on the rotor

5 R_L rotor length

T_cw total cutting width

The design considerations regarding size, peripheral cutting speeds and inertial loads have shown that a cutting profile (C_P) of 600mm is near to the optimum, however other sizes in the range C_P = 250 - 1000mm could be used.

Using a value of C_P - 600mm gives a starting point from which to derive the other machine parameters.

1. C_EFF (this assumes S - 80mm)

By referring to Fig 4 and scaling the drawing it is found that C_EFF = C_{P 2} for the parameters C_P = 600mm and S = 80mm.

2. C_w (Fig 5)

Referring to Fig 5 the relationship is as follows:- _\\r ⁼ CO CC g_FF using C_P = 600 for this particular case C_W = COSCC 300

3. F_s

Referring to Fig 5 the relationship is as follows:-

SLNtX = C_w/F_s thus F_s - C_w/SLNα

4. R_L

Referring to Fig 6

RL = T_cw/SLNα These equations allow the calculation, for specific angles of OL, of the design parameters for the machine's cutting rotor. The following table A shows the different values of C_w, F_s, R_L and number of flanges per rotor for different values of OL. The calculations are based on a cutting profile (C_P) of 600mm.

TABLE A

α° CW FS RL No. ofFlanges mm mm mm

10 295 1699 25914 16

15

20 282 824 13157 17

25 272 643 10648 17

30 260 520 9000 18

35

40 230 358 7000 20

45 212 300 6364 22

50 193 252 5874 24

55 172 210 5493 27

60 150 173 5196 31

65 126 140 4965 36

70 103 110 4789 44

75

80 52 53 4569 87

In conclusion it can be seen from the table that as OL approaches either 0° or 180° then the rotor length becomes impractical lengthwise. At the other end of the scale when OL is approaching 90° from either the forward or trailing rotor angles the increase in the number of rotor flanges becomes the limiting design parameter.

It appears that when OL = 45 °, either forward or trailing, the optimum design is achieved.

Feasible designs would be also possible where OL is between 30 °-65° and 115°-150° these ranges relating to both the forward and trailing attitudes of the rotor angle.

The mowing machine of the invention provides a relatively low power flail mower which is capable of mowing crop in the manner not hitherto possible with flail mowers but without the attendant disadvantages of disc mowers currently used for this purpose.

Claims

1. An agricultural mowing machine comprising a rotatable driven shaft, flail cutting elements mounted on the shaft for rotation therewith and spaced apart in the axial direction of the shaft, and a mounting for the shaft arranged so that in use the axis of the shaft is located at an acute angle in the range 30┬░- 65┬░ to the direction of travel of the machine over the ground.

2. A mowing machine according to claim 1 in which the acute angle is in the range 40┬░ - 50┬░ to the direction of travel.

3. A mowing machine according to claim 1 or 2 wherein the shaft carries a plurality of flanges mounted on the shaft and the planes of the flanges lie perpendicular to the axis of rotation of the shaft and the flanges are spaced apart from each other along the shaft.

4. A mowing machine according to claim 3 wherein the flanges each carry at least one flail cutting element pivotally mounted on the associated flange and having a cutting portion which extends radially outwardly from the shaft during rotation of the shaft, the pivot axes of the elements lying parallel to the axis of the shaft.

5. A mowing machine according to claim 3 or 4 wherein the cutting elements are of generally L-shape, one limb of the L being pivotally attached to the associated flange, and the other limb of the L constituting the cutting portion.

6. A mowing machine according to any one of the preceding claims wherein the machine is arranged for mounting on a tractor three-point linkage and the shaft is arranged to be driven by the tractor power take off, the shaft being offset from the tractor to one side of the direction of travel of the tractor.

7. A mowing machine according to claim 6 wherein the inclination of the axis of the shaft to the direction of travel is such that the shaft is inclined at said acute angle in a forwards or rearwards direction with respect to the direction of travel.

8. A mowing machine according to claim 3 or 4 wherein the length of the shaft, the spacing apart of the flanges, the radius of rotation of the cutting elements, and the cutting width of the elements are selected according to the acute angle, the required width of cut of the machine, the height at which the cutting elements are to operate and the available power.

9. A mowing machine in which the acute angle is approximately 45 ┬░ and the rotational diameter of the cutting elements is in the range 250- 1000mm, preferably approximately 600mm.

10. A mowing machine according to claim 9 wherein the maximum height of crop cut by the cutting elements is approximately 80mm and the cutting width for each flange is about 300mm.

11. A mowing machine according to any one of the preceding claims comprising conveyor means arranged to the rear of the shaft for conveying cut material to one side of the machine.

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