GB2346790A

GB2346790A - Mowing head drives

Info

Publication number: GB2346790A
Application number: GB9903885A
Authority: GB
Inventors: Christopher Martin Lole
Original assignee: Spearhead Machinery Ltd
Current assignee: Spearhead Machinery Ltd
Priority date: 1999-02-19
Filing date: 1999-02-19
Publication date: 2000-08-23
Anticipated expiration: 2019-02-19
Also published as: GB2346790B; GB9903885D0

Abstract

A mowing machine comprises a main frame 6, a mowing head 1, a support arm 3 connected to the mowing head 1, and a substantially horizontal hinge 9 connecting the support arm 3 to the main frame 6. The mowing head 1 is pivoted between a raised transport position and a lowered working position by means of an hydraulic ram 5. The mowing head 1 is driven by an arrangement of rotating shafts 4 and 10 incorporating a device 8 for transmitting the rotation of a first shaft 4 to a second shaft 10 lying at an angle to the first shaft 4, in which the axis of the first shaft 4 is substantially co-linear with the hinge 9 about which the support arm 3 swings.

Description

DESCRIPTION "IMPROVEMENTS TN MOWING HEAD DRIVES" The present invention refers to machinery for mowing grass and similar vegetation in which the mowing head incorporates flails on rotating spindles to effect the required removal of excess vegetation. The flails may extend centrifugally from a rotor with axis perpendicular to the ground or the flails may extend from a rotor with axis parallel to the ground.

The present invention refers in particular to machines required to mow a path outside the track of the towing vehicle. These are usually arranged so that the arm supporting a mowing head outside the vehicle track can be swung from a horizontal to an approximately upright position, say during passage through gateways and along roads. That is, the arm is hinged about a horizontal pin, and can be swung between working and transport positions.

Because of the power requirement to drive the rotors of flail mowing machines most rotor drive systems are comprised of rotating shafts adapted for connection to the mechanical power take-off connection of the farm tractor invariably used as the towing vehicle.

A rotating shaft transits power laterally to the direction of mowing to reach a mowing head positioned outside the track of the towing vehicle. In general this is a cardan shaft arrangement incorporating a spline and flexible couplings to accornmodate variations in relative position as the mowing head follows ground irregularities. The flexible coupling is usually a Hooke's joint.

Hitherto, all such machines have encountered problems with the transmission shaft as described. In known constructions the axis of the transmission shaft is some distance removed from the hinge about which the arm carrying the mowing head swings. A first consequence of the known construction is that when the arm carrying the mowing head is swung up about the hinge to the transport position the spline section of the transmission shaft is considerably shortened. A second consequence is that during this action one of the universal joints is turned through approximately a right angle.

The difficulty with the first consequence is that a very long spline has to be installed, and the spline is in the fully extended condition when running at maximum torque, It is therefore prone to vibration and breakdown, being expensive in maintenance as well as in first cost.

The difficulty with the second consequence is that the drive system must not be allowed to continue any rotation after the arm has begun its upward swing.

Unfornmately, operatives can inadvertently neglect to observe this requirement with the result that the universal joint is broken by the drive turning. Production is lost and expense incurred. The necessity to stop the drive completely before swinging up one of the mowing heads prevents the driver from avoiding an obstruction such as a bush by elevating one head as the tractor passes it.

It is an aim of the present invention to provide a shaft drive system to a mowing head in which whatever the elevation angle of the mower supporting arm, the universal joint can be operated safely, and the spline section will undergo little axial motion.

According to the present invention there is provided a mouing machine comprising a main frame, a mowing head, a support arm connected to the mowing head, a substantially horizontal hinge connecting the support arm to the main frame whereby the mowing head can be pivoted between a raised transport position and a lowered working position, wherein the mowing head is driven by an arrangement of rotating shafts incorporating a device for transmitting the rotation of a first shaft to a second shaft tying at an angle to the first shaft, in which the axis of the first shaft is substantially co-linear with the hinge about which the support arm swings.

Preferably, the transmission device is mounted on the support arm.

Preferably, the transmission device is a gearbox, The gear box may comprise bevel wheels.

The arrangement of rotating shafts following the second shaft may incorporate at least one flexible coupling.

The mowing machine may comprise a plurality of mowing heads each connected to the main frame by means of a respective support arm and hinge and each driven by a respective arrangement of drive shafts. Each of the said first shafts is connected to a common drive shaft via respective drive transmission means which conveniently takes the form of a drive pulley and drive belt. The common drive shaft is mounted on the main frame.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which :- Figure 1 is a diagrammatic side view of a mowing head, its supporting arm and drive mechanism, the axis of the mowing head being parallel to the ground, forming part of a mowing machine embodying the present invention ; Figure 2 is a similar view of the machinery shown in Fig 1 in which the mowing head has been elevated, its axis being perpendicular to the ground; Figure 3 is a plan view of the machinery shown in Figure 1; Figure 4 is a view facing the rear of the towing vehicle of part of a mowing machine embodying the present invention showing two mowing heads on hinged arms.

Figure 5 is a plan view of part of the mowing machine shown in Figure 4, but both arms are in the working position.

Referring to Figures I and 3 there is shown a mowing head 1 which is supported from a pair of arms 3 at respective pivots 2. The pivots 2 permit the mowing head 1 to rock and accommodate ground irregularities.

The arms 3 can be swung upwardly relative to a main frame 6 (only partially shown) of the mowing machine about a hinge or pivot formed by hinge pins 9 (see Figure 3). The upward swing is executed by an hydraulic ram 5, and the arms 3 can be raised to the extent shown in Figure 2.

Referring to Figure 3 it can be seen that a shaft 4 lies co-axial to the hinge pins 9. The shaft 4 is adapted to be connected to a rotary power output via coupling means 7 provided at one end. It will be understood that rotary power may be applied to the shaft 4 by other means, for example, by a belt and pulley drive system.

The shaft 4 passes into a gearbox 8, which is fixed to the arm 3 as shown in Figure I by a bracket 16. The gearbox 8 is, in the present example, a rightangled drive of step-up ratio 2.58 to its output shaft 10, A flexible coupling 11 connects the shaft 10 to a splined transmission shaft 12, at the other end of which is a second flexible coupling 13. The coupling 13 is connected to a lay shaft 14, which is shown in the figures encased within a guard.

The lay shaft 14 and the shaft 10 are parallel when the pivot 2 is in mid-position so that the shafts 10,12 and 14 form a cardan arrangement.

The outer end of lay shaft 14 carries a belt drive 15 leading to the rotor of the mowing head 1. Means not shown in the figures facilitate positioning of the lay shaft 14 for tensioning of the belt drive 15.

In operation, rotary drive is applied to the coupling means 7 of the shaft 4 by direct or indirect means from the power take-off connection of the towing tractor. This operates the rotor of the mowing head whatever the angle of elevation of the arm 3 without disturbing the arrangement of the transmission leading to the rotor. The procedure of elevation does not significantly change the extension of the spline in the shaft 12.

Thus the aims of the invention are achieved. The installed spline can be a very short one, The operator can fully elevate the mowing head without any concern about first disconnecting drive, as in prior equipment. The operator can elevate a head clear of an obstruction close to the track of the towing vehicle.

The example described is a single mowing head disposed laterally from the track on which the towing vehicle is being driven, and the present example describes a flail rotor with axis parallel to the ground. It will be understood that a pair of such mowing heads can be mounted, one to either side of the main frame, and that a further mowing head can be towed at the same time within the track of the vehicle, as is frequently practised. It will be further understood that similar examples of the same invention can be arranged with flail rotors having vertical axis of rotation.

A further advantage of the invention derives from the flexibility it gives in operating drive branches. It becomes practicable to operate flail mowing machines with a larger number of mowing heads, each smaller than hitherto. Ground contours can then be followed more accurately, as is found with multiple-head cylinder mowers.

In the example as described so far it will be understood that, where two hinged arms 3 are disposed one to each side of the towing vehicle, the input drive (Figure 3) can operate both gearboxes 8 if both are positioned in line on the shaft 4. Each gearbox 8 is fixed to its respective arm 3. Furthermore, the hinge centres 9 of both arms 3 must be coincident with the single shaft 4. It will also be understood that the end of shaft 4 opposite to the input drive 7 connects to a third mower head not shown in the drawings but towed within the track of the towing vehicle, as is common practice with machines of this type.

Figures 4 and 5 show an embodiment of the present invention comprising two mower heads, one on each side of the main frame, One arm projects laterally off the track of the towing vehicle and is in the working position the other arm is raised to the transport position. A third mowing head, which is normally part of the machine, and is towed in line with the vehicle track, is not shown. Where two hinged arms 3 are positioned one to each side of the towing vehicle, their hinge pins 9 can be displaced one to each side of the centre line of the base 6. Each of their shafts 4 and gearboxes 8 remains in line with the respective hinge pins 9, as shown in Figure 5, Each of the shafts 4 is turned by a belt drive 16 from a common shaft 17.

A coupling 18 at the forward end of the shaft 17 is j oined to the power takeoff connection of the tractor. A coupling 18 at the rearward end of the shaft 17 is joined to the third mowing head normally towed behind the tractor with this type of machinery, but omitted from the Figures for clarity.

The belt drive 16 is adjusted to the correct tension by regularly used means not shown in the Figures.

Claims

CLAIMS 1. A mowing machine comprising a main frame, a mowing head, a support arm connected to the mowing head, a substantially horizontal hinge connecting the support arm to the main frame whereby the mowing head can be pivoted between a raised transport position and a lowered working position, wherein the mowing head is driven by an arrangement of rotating shafts incorporating a device for transmitting the rotation of a first shaft to a second shaft lying at an angle to the first shaft, in which the axis of the first shaft is substantially co-linear with the hinge about which the support arm swings. 2. A mowing machine according to claim 1, wherein the transmission device is mounted on the support arm. 3. A mowing machine according to claim 1 or 2, wherein the transmission device is a gearbox. 4. A mowing machine according to claim 3, wherein the gear box may comprise bevel wheels. 5. A mowing machine according to any preceding claim, wherein the arrangement of rotating shafts following the second shaft incorporates at least one flexible coupling. 6. A mowing machine according to any preceding claim comprising a plurality of mowing heads each connected to the main frame by means of a respective support arm and hinge and each driven by a respective arrangement of drive shafts. 7. A mowing machine according to claim 6, wherein each of the said first shafts lie on the same axis. 8. A mowing machine according to claim 6, wherein each of the said first shafts is connected to a common drive shaft via respective drive transmission means. 9. A mowing machine according to claim 8, wherein the drive transmission means takes the form of a drive pulley and drive belt. 10. A mowing machine according to claim 8 or 9, wherein the common drive shaft is mounted on the main frame. 11. A mowing machine substantially as hereinbefore described with reference to the accompanying drawings. Amendments to the claims have been filed as follows

1. A vegetation maintenance mowing machine comprising a main frame, a mowing head, a support arm connected to the mowing head, a substantially horizontal hinge connecting the support arm to the main frame whereby the mowing head can be pivoted between a raised transport position and a lowered working position and drive means whereby the mowing head is rotatably driven, wherein the mowing head is driven by an arrangement comprising a transmission device, a first shaft connected at one end to the drive means and at the other end to the input side of the transmission device, and a second extensible shaft connected at one end by a first universal coupling to the output side of the transmission device and at the other end by a second universal coupling to the mowing head, the second shaft lying at an angle to the first shaft, and the axis of the first shaft being substantially co-axial with the hinge about which the support arm swings.

2. A mowing machine according to claim 1, wherein the transmission device is mounted on the support arm.

3. A mowing machine according to claim 1 or 2, wherein the transmission device is a gearbox.

4. A mowing machine according to claim 3, wherein the gear box may comprise bevel wheels.

5. A mowing machine according to any preceding claim, wherein the mowing head comprises a plurality of rotating shafts incorporating at least one flexible coupling.

6. A mowing machine according to any preceding claim comprising a plurality of mowing heads each connected to the main frame by means of a respective support arm and hinge and each driven by a respective arrangement of first and second shafts, and a transmission device.

7. A mowing machine according to claim 6, wherein each of the said first shafts lie on the same axis.

8. A mowing machine according to claim 6, wherein each of the said first shafts is connected to a common drive shaft via respective drive transmission means.

9. A mowing machine according to claim 8, wherein the drive transmission means comprises a drive pulley and drive belt.

10. A mowing machine according to claim 9, wherein the transmission device is mounted on the support arm by means enabling its position to be varied in the direction of the length of the support arm, thereby allowing the tension in the drive belt to be adjusted..

11. A mowing machine according to claim 8,9 or 10, wherein the common drive shaft is mounted on the main frame.

12. A mowing machine substantially as hereinbefore described with reference to the accompanying drawings.