NZ514549A - Self-propelled irrigator - Google Patents

Abstract

A self-propelled irrigation system. The system includes: a ground-engaging vehicle (100) propelled by a liquid pressure activated drive; a rotating boom (1) supported on the vehicle, the boom having at least one sprinkler (2) fixed thereto; a relatively flexible conduit (14) adapted to be fixed to a supply main for supplying pressurized liquid to the vehicle; and means (12) for restraining the travel of the vehicle along a closed path.

Description

PATENTS FORM NO. 5 PATENTS ACT 1953 COMPLETE SPECIFICATION After Provisional No: 514549 Dated: 01 October 2001 James & Wells Ref: 41624/24 SELF-PROPELLED IRRIGATOR We, Kirk Irrigation Ltd of No 8 R D, Mill Road, Waimate, New Zealand, a New Zealand Company, hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: Intellectual Property Office of N.Z. 2 5 NOV 2002 R E C E I V I::. D ! i SELF-PROPELLED IRRIGATOR Technical Field The present invention relates generally to travelling sprinkler irrigation, and more particularly 5 to self-propelled sprinkler systems for pastoral irrigation.

Background Art One type of continuously-moving sprinkler system is the centre-pivot system, which consists of a lateral line with sprinkler heads spaced on it. The pipe is suspended above ground on individually powered tower units. The system is self-propelled, each tower driven by individual electric or hydraulic motors, and continuously rotates around a pivot point through which water is supplied. A disadvantage of centre-pivot systems is that, since their travel is along a circular path, they cannot irrigate the corners of the field. Travelling sprinkler systems may be used to overcome this disadvantage.

Common travelling sprinkler systems consist of a wheeled cart with a large sprinkler (more commonly called a "gun"), a hose reel winder, and an irrigation hose. The wheeled cart is pulled either by a cable or a hard irrigation hose during operation. 2 0 Hard hose travelling guns are characterised by the "hard hose" (as opposed to a "soft" collapsible hose) which is wound around a hose reel with the end of the hose attached to a wheeled gun cart. In operation the gun cart (with the hose attached) is pulled out some distance from the winder. The pump is then started, which provides water to the "gun" and the hose reel then begins to slowly "reel in" the gun cart as the sprinkler operates. 2 ' There are several "drive" or reel-in power systems for travelling guns. In a turbine drive a portion (or all) of the irrigation water flows through the turbine on the way to the gun. The flow of the water pushes vanes or paddles on the turbine, which in turn powers the hose reel.

An engine drive system is a fairly simple system where, for example, a small petrol 5 engine is mounted on the winder. Another power type is a water-powered bellows-drive system, during operation water fills a diaphram or "bellows," which in turn expands providing the force to reel the hose in. After a valve releases the water inside the bellows it then contracts and the cycle begins again.

New Zealand patent No. 210739/210791 describes a travelling irrigator supplied by a flexible water supply hose which is drawn along over the ground. A rotating boom driven by water jet reaction drives a winch engaging an anchored cable to pull the irrigator in a linear fashion. This irrigator, however, like other travelling gun systems, is limited to linear movement in one direction having a maximum length of travel which is no more than twice the hose length 15 or the length of the cable. The other major drawbacks of the travelling gun system are that it is quite labour intensive and operates at a low efficiency (at an application rate which is too high for optimum absorption).

It is an object of the present invention to address the foregoing problems or at least to provide 2 0 the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only. 3 Disclosure of Invention According to one aspect of the present invention there is provided a self-propelled irrigation system including: a ground-engaging vehicle propelled by a liquid pressure actuated drive; a rotating boom supported on the vehicle, the boom having at least one sprinkler fixed thereto; a relatively flexible conduit adapted to be fixed to a supply main for supplying pressurised liquid to the vehicle; and means for restraining the travel of the vehicle along a closed path.

Although reference is made herein to an irrigation system, this should not be seen as limiting, and it will be appreciated that the system may be used for applying liquids other than water e.g. effluent. While it is preferably used for irrigating pastoral land, the system may also be employed for irrigating vegetation, e.g. grass on a sports ground, commercial or domestic lawn etc.

Preferably a swivelling connector is provided at one end of the flexible conduit for connection to the supply main. The flexible conduit is preferably a plastic hose, or the like, connected to riser from a buried mainline.

Preferably the means for restraining the travel of the vehicle along a closed path includes a loop of track set out on the area to be irrigated and a guide fixed to the vehicle for engagement with the track. Alternatively the vehicle may be steered in a closed path by other means, such as radio, infrared or satellite based guidance systems or magnetic induction sensors for following a buried conductor.

Most preferably the track comprises a groove formed in the area of pasture to be irrigated and the vehicle includes one or more drive wheels. A skid, or alternatively a wheel, travels in the 5 groove to provide steering. Tracks or other means may also be used to engage with the ground to propel the vehicle.

According to another aspect of the present invention there is provided an irrigation system substantially as described above wherein the boom has a water jet sprinkler fitted at the distal 10 end thereof to turn the boom by water jet reaction and wherein rotation of the boom provides the said drive for propelling the vehicle.

Alternatively the liquid pressure actuated drive may be a turbine, bellows or piston type.

Preferably the boom oscillates and power from the oscillation of the boom is transmitted mechanically to the drive wheel or wheels.

Preferably the boom oscillates about a substantially vertical axis and a pitman arm connects the boom to a rocker which pivots about a substantially horizontal axis, the oscillating 2 0 movement of the rocker driving the drive wheel or wheels through a reverse-rotation preventing mechanism. In the preferred embodiment the reverse-rotation preventing mechanism comprises a ratchet wheel and two locking pawls, optionally other known devices such as one-way clutches may be employed.

Preferably water is supplied to the boom through a flexible hose mounted either above or below the boom to accommodate the rotation and/or movement at the attachment point. Alternatively, the water may be supplied through a swiveling gland fixed about the pivot point.

Preferably the wheels and skid are mounted in a triangular arrangement, with two driven rear wheels and the skid front-mounted.

According to another aspect of the present invention there is provided a method of irrigating a pasture, including: providing an irrigation system substantially as described above; providing a loop of track to restrain the travel of the irrigation system along a closed path, and supplying pressurised liquid to the irrigation system.

Compared to the linear-move systems of the prior art, which have a travel limited to the lesser of twice the length of the supply hose or the cable length, the device is not restricted to linear operation and can travel along a path, each circuit of which is over six times the length of the hose in order to irrigate a large area in a continuous cycle.

This invention provides an irrigation system which is effective and efficient in operational use, requiring minimal labour input, and having low maintenance costs. The device may be economically constructed and has an overall simple design which minimizes manufacturing costs and maximizes performance.

Brief Description of Drawings Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which: Figure 1 is a side elevation of an irrigator of the present invention; Figure 2 is a plan of the irrigator of Fig. 1; Figures 3a, 3b and 3c are plan views illustrating alternative tracks followed by an irrigator in use; Figure 4a is a section through a track as shown in Fig. 3a, 3b and 3c; Figure 4b is an expanded detail of part of Fig. 1, and Figure 5 is a plan view of a rear section of the irrigator of Fig. 1.

Best Modes for Carrying out the Invention Referring to Fig. 1, a preferred embodiment of the self-propelled irrigator 100 includes a boom 1 rotatable about a substantially vertical axis A and having a rotating water jet sprinkler 2 fitted at the distal end of the boom 1 to turn it by water jet reaction. The boom 1 is counterbalanced by a weight 3 connected by a main structural member 4 to the supporting pivot 5. The structural member 4 tapers from the pivot 5 toward the distal end of the boom 1 and is braced by additional structural members 6.

The boom 1 is supported upon a ground-engaging vehicle 10 which in operation is driven forward in direction F by means of energy from the irrigation water supplied to the irrigation system 100 through the hose 14, which it draws over the ground surface 15. The vehicle 10 includes two rear driven wheels 11, laterally spaced either side of the pivot 5 and a front skid 12 which controls the direction of travel by engaging with a groove 16 (see Fig. 4a) forming a guide track in the surface 15. In addition to the weight 3, the wheels 11 are ballasted with water and other ballast may also be provided to provide sufficient traction to propel the vehicle 10 and draw along the hose 14.

As shown in Fig. 2 (and described more fully below with respect to Figs. 4 and 5) in the preferred embodiment the boom 1 oscillates - moving the sprinkler 2 back and forth in an arc of approximately 12 metres through an angular swept path of between 160° - 200°. An efficient low application rate is thereby provided which avoids water losses through run-off and leaching.

Figures 3a, 3b and 3c illustrate the manner in which the irrigator 100 may be employed to provide continuous irrigation of a large area by providing a groove 16 forming a guide track to move the irrigator 100 in a continuous closed path. The flexible hose 14 (e.g. a polyethylene hose) supplies water to the irrigator 100 via a swivel connection 9 (see Fig. 1) to a centrally located hydrant 17. It will be appreciated that due to the manner in which the hose 14 is drawn across the ground, the irrigator 100 is best suited to pastoral irrigation. The shape of the closed path may vary to accommodate different shaped areas, although it is limited by the necessity to avoid running over the hose 14.

The supply hose 14 connects to the vehicle 10 at a low position between the wheels 11, as shown in Fig. 4b. A water passage is provided through a main longitudinal member 13 and a vertical pipe 18 of the vehicle 10 before passing through a valve 8 into a flexible hose 19 which is connected to the member 4. The water passes through the member 4 to the sprinkler 2. The hose 19 connects to the boom 1 at a point 20 radially offset from the pivot axis A, however this point has only a relatively small movement during oscillation of the boom 1 and this is readily accommodated by flexure in the hose 19.

The structural members 6 supporting the boom 1 include a generally vertical stay post 32 and stay wires 33. Positioned in a medial section of the boom 1 a spray nozzle 41 provides an omni-directional water spray pattern.

The oscillatory movement of the boom 1 is restrained at both ends by means of a rope 21 connected with a damper 22 between the vehicle 10 and the boom 1. The damper 22 absorbs excess energy in the boom 1 at the limits of its movement and provides a "soft" stop.

A mechanism 30 is provided to convert rotation of the boom 1 about the vertical axis A into 15 rotation of the wheels 11 about their horizontal axis, thereby propelling the irrigator 100. Referring to Figs. 4 and 5, the mechanism 30 includes a pitman arm 31 connected to the boom 1 and a rocker assembly 34 hingedly fixed about an axis generally parallel to the axis of the wheels 11. Oscillation of the boom 1 thereby causes a corresponding oscillation of the rocker assembly 34. A ratchet wheel 35, together with two locking pawls 36 and 37 form a 2 0 reverse-rotation-preventing ratchet mechanism of a known type which is driven by the rocker assembly 34.

The ratchet wheel 35 is formed integrally with the axle 38 for driving the wheels 11. Both the rocker 34 and the axle 38 are supported in bearings (not shown) for rotation relative to the 9 transverse member 13'. The ratchet wheel 35 includes teeth (not shown) around the whole circumference thereof. The teeth have a directional shape adapted to engage with the locking pawls 36 and 37. The pawls 36 and 37 are biased against the ratchet wheel 35 by spring means (not shown). The drive pawl 36 is fixed to the rocker assembly 34 and the detent pawl 37 onto the frame 13. It will be appreciated that the speed of travel of the vehicle 10 may be varied according to the number of teeth in the ratchet wheel 35 which are indexed with each oscillation of the boom 1. Accordingly, increasing the angular swept path of the boom 1 increases the speed of travel.

The mechanical and structural components of the irrigator 100 may be made substantially of steel, or other suitable material.

In use of the irrigation system, the surface to be irrigated is cleared of anything that would obstruct the travel of the irrigator 100 (particularly the hose 14) and a groove 16 is provided in a continuous loop. As shown in Fig. 4a, in pasture the groove 16 may be approximately 100mm below the grass level and 100mm wide and can be conveniently produced by a using a cutting tool drawn by a tractor. Once the skid 12 is placed in the groove 16 and pressurised water is supplied from the central hydrant 17 the irrigator 100 operates at a speed which may be varied by controlling the angular travel for the rotating sprinkler 2. Once set up in this way there is no need for any further control or labour input.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions maybe made thereto without departing from the scope thereof.

Claims (13)

WHAT WE CLAIMS IS:

1. A self-propelled irrigation system, including: 5 a ground-engaging vehicle propelled by a liquid pressure actuated drive; a rotating boom supported on the vehicle, the boom having at least one sprinkler fixed thereto; a relatively flexible conduit adapted to be fixed to a supply main for supplying pressurised liquid to the vehicle; and 10 means for restraining the travel of the vehicle along a closed path.

2. The self-propelled irrigation system of claim 1 wherein a swivelling connector is provided at one end of the flexible conduit for connection to the supply main. 15

3. The self-propelled irrigation system of claim 1 or claim 2 wherein the flexible conduit is a plastic hose connected to a riser from a buried mainline. 20

4. The self-propelled irrigation system of any one of the preceding claims wherein the means for restraining the travel of the vehicle along a closed path includes a loop of track set out on the area to be irrigated and a guide fixed to the vehicle for engagement with the track. 25

5. The self-propelled irrigation system of claim 4 wherein the track comprises a groove 11 5145 formed in the area to be irrigated and the vehicle includes one or more drive wheels or tracks engaged with the ground. 5

6. The self-propelled irrigation system of claim 5 wherein a skid travels in the groove to provide steering.

7. The self-propelled irrigation system of any one of the preceding claims wherein the boom 10 has a water jet sprinkler fitted at the distal end thereof to turn the boom by water jet reaction and wherein rotation of the boom provides the drive for propelling the vehicle.

8. The self-propelled irrigation system of any one of the preceding claims wherein the boom 15 oscillates and power from the oscillation of the boom is transmitted mechanically to drive one or more drive wheels or tracks.

9. The self-propelled irrigation system of any one of the preceding claims wherein the boom 2 0 oscillates about a substantially vertical axis and a pitman arm connects the boom to a rocker which pivots about a substantially horizontal axis, the oscillating movement of the rocker driving one or more drive wheels or tracks through a reverse-rotation preventing mechanism. Intellectual Property Office of NZ 0 7 MAR 2003 12

10. The self-propelled irrigation system of claim 9 wherein the reverse-rotation preventing mechanism comprises a ratchet wheel and two locking pawls.

11. The self-propelled irrigation system of claim 6 wherein two wheels and the skid are mounted in a triangular arrangement, the two wheels being driven and positioned on opposing sides of a longitudinal axis of the vehicle and the skid being front-mounted.

12. A method of irrigating a pasture, including: providing an irrigation system as claimed in any one of claims 1 to 11; providing a loop of track to restrain the travel of the vehicle along a closed path, and supplying pressurised liquid to the irrigation system.

13. A self-propelled irrigation system substantially as described hereinbefore with reference to the accompanying drawings. 10 15 20 END OF CLAIMS KIRK IRRIGATION LTD By its authorised agents JAMES & WELLS 25 Intellectual Office of Sm.z 2 5 MOV 2002 R BC'r i\f 13