GB2110062A - Improvements in or relating to crop spraying equipment - Google Patents

Abstract

A boom assembly for crop spraying carries spray nozzles 3 and is divided into a central section 6 and side sections 7, 8 which can be pivoted in relation to the central section 6 to enable the assembly to be collapsed or folded in to a towing vehicle. Each side section 7, 8 is linked to the central sections 6 with the aid of flexible pivot bearings 10, 11 which constrain the side sections 7, 8 to move upwardly and inwardly when the boom assembly is collapsed. Double acting hydraulic rams 12 serve to pivot the side sections 7, 8 in relation to the central section 6 and the rams 12 are connected to the sections 6, 7, 8 via damping springs 18 which take up shock and centrifugal force. <IMAGE>

Description

SPECIFICATION Improvements in or relating to crop spraying equipment The present invention relates in general to crop spraying equipment. More particularly, the invention relates to an improved boom assembly for such equipment.

As is known, a conventional type of agricultural crop spraying equipment employs a collapsible or foldable elongate boom assembly mounted at the rear of a vehicle and serving to spray jets of liquid from downwardly directed nozzles. The boom assembly has side sections which are pivotably connected to a central section and these side sections can be swung inwards and stowed when the equipmet is not used. Boom assemblies of various lengths can be provided to provide different spray widths. Various problems occur with the conventional boom assemblies, especially with assemblies of great length as discussed hereinafter and a general object of the present invention is to provide an improved form of boom assembly for crop spraying equipment.

In one aspect the present invention provides a boom assembly for crop spraying equipment; said assembly comprising a central section and side sections each pivotably mounted to the central section by offset pivot joints adapted to permit the side section to swing through arcuate paths and move vertically to some extent between an open working position aligned with the central section and a stowed collapsed position. The pivot joints are preferably flexible and may incorporate spherical bearings. The pivot joints for each side section may comprise upper and lower pivot joints which define generally upstanding pivot axes offset in two dimensions, laterally and longitudinally of the boom assembly.

In another aspect, the present invention provides a boom assembly for crop spraying equipment, said assembly comprising a central section and side sections, each pivotably mounted to the central section for swinging between an open working position aligned with the central section and a stowed coilapsed position and double-acting hydraulic rams for pivoting said side sections, the rams being connected between the central and side sections via linkages employing damping means for absorbing shock and centrifugal force during use. Preferably the pivot mounting is constructed from offset pivot joints as aforesaid. The damping means may be composed of springs transmitting thrust and tensile forces from the rams to a fixed mounting such as a bracket.Preference may be given to a construction where each ram is connected to a threaded rod extending through the mounting with springs engaged between the mounting and washers located by nuts. Such nuts then permit adjustment of the damping force and also permit the open and stowed positions of the side sections to be adjusted.

According to a further preferred feature of the invention the rams have components guided for horizontal displacement by sleeves or similar guideways.

This invention may be understood more readily and various other features of the invention may become apparent from consideration of the following description, in conjunction with the accompanying drawings, wherein Figure 1 is a perspective view of a typical spraying unit of known type.

Fig. 1 depicts by way of example, a typical crop spraying unit of the type with which the present invention is concerned. As shown, the unit employs an elongate boom assembly 1 mounted at the rear of a vehicle 2 which may be a trailer or a self-propelled vehicle. The boom assembly 1 extends over a considerable distance typically up to 24 metres and carries a plurality of ground-directed nozzles 3 which spray liquid stored in a tank 4. The whole boom assembly 1 can be raised or lowered by means of hydraulic rams 5. The boom assembly 1 is constructed from a central section 6 and one or more side sections 7, 8. These side sections 7,8 can be pivoted about upstanding axes to enable the assembly 1 to adopt an open working position as shown or a collapsed or stowed position.During operation, considerable loading is imparted to the long boom assembly 1 due to shock and to centrifugal forces caused when the vehicle is turning. The steering of the vehicle can also be adversely affected by the boom assembly 1 and in certain circumstances it can be difficult to move the vehicle in a straight path. In an attempt primarily to absorb shock loads, it has been known to link each of the side sections 7,8 of the boom assembly 1 to the central section 6 with a pivot joint supported by rubber pads. This arrangement has not proved wholly satisfactory. The rubber pads can wear and it then becomes difficult to align the sections 6,7,8 of the boom assembly when in the open or extended position. This problem can be aggravated by premature aging of the rubber pads caused by exposure to the chemical(s) in the spray. The present invention seeks to mitigate these problems.

An embodiment of the invention will now be described, by way of example only with reference to the remaining Figures of the accompanying drawings wherein: Figure 2 is a schematic plan view of part of a spray boom assembly constructed in accordance with the invention; and Figure 3 is a schematic rear elevation of the part of the spray boom shown in Fig. 2.

In Figs. 2 and 3, only one boom assembly side section 7 is shown for convenience but the other side section and its linkage to the central section 6 is constructed in a similar manner to that described and illustrated for the side section 7. As shown the side section 7, is connected to the central section 6 by means of upper and lower pivot joints 1 1.

Each pivot joint 10,11 employs a spherical bearing or the like providing at least some degree of universal movement. As shown in Fig. 2, the pivot axes of the joints 10,11 which extend more or less vertically, are offset. A double-acting hydraulic ram 1 2 serves to swlng the section 7 on the pivot joints 10,1 ì relative to the centre section 6. The ram 1 2 takes a horizontal position and in the retracted position maintains the section 7 in the open working position. Because of the offset axes of the pivot joints 1 0,11 extension of the ram 1 2 to bring the section 7 to a collapsed stowed position will result in an upward as well as in inward movement of the section 7.This combined vertical and arcuate movement of the side sections is advantageous since it enables the side sections to be stowed neatly alongside the vehicle carrying the boom assembly without increasing the overall length of the equipment. The boom assembly can thus be constructed from just two side sections and a central section even with a boom assembly of maximum length and the chassis of the vehicle can be maintained at a reasonable length.

The ram 1 2 is operably connected between the boom assembly sections 7,6 via a linkage 14 employing damping means adapted to absorb shock and centrifugal forces. As illustrated, the piston rod of the ram 1 2 is connected to a lower component of the section 7 via a pivot joint 1 3 while its cylinder is connected via another pivot joint 24 to a guided rod or tube 1 5. The rod 1 5 slidably extends within a guide sleeve 1 6 fixed to the centre section 6 and this ensures that the force exerted by the ram 1 2 is directed horizontally.The rod 1 5 is connected to a further rod 1 6 provided with a screw-thread onto which adjustment nuts 1 7 and washers 1 9 are engaged. The threaded rod 1 6 extends through a bracket 20 or the like fixed to the boom assembly section 6. A pair of opposed compression springs 1 8 each surround the nut 16. The springs 18 engage on the bracket 1 7 and on the washers 1 9 positioned by the nuts 14. Thrust or tensile force produced by the ram 1 2 thus acts through one or other of the springs 1 8 on the bracket 20. During operation, shock and centrifugal forces will be taken up by the springs 1 8 and moreover the tendency of the boo assembly to affect steering is reduced. The nuts 14 can be relatively positioned on the rod 1 6 to control the open and stowed positions adopted by the section 7 and the nuts 14 can be adjusted together to control the damping force provided by the springs 18. If the ram 1 2 has a fixed working stroke the linkage 14 can thus be adjusted from time-to-time to compensate for wear.

Claims (14)

1. A boom assembly for crop spraying; said assembly comprising a central section and side sections equipped with spray nozzles, each side section being pivotally mounted to the central section by means of off-set pivot joints adapted to permit the side sections to swing through arcuate paths and move vertically to some extent between an open working position aligned with the central section and a stowed collapsed position.

2. A boom assembly according to claim 1, wherein the pivot joints are flexible.

3. A boom assembly according to claim 1, wherein the pivot joints incorporate spherical bearings.

4. A boom assembly according to claim 1, wherein the pivot joints are in the form of universal joints.

5. A boom assembly according to any one of claims 1 to 4, wherein each side section is pivoted to the central section by means of upper and lower pivot joints which define generally upstanding pivot axes off-set in two dimensions laterally and longitudinally of the assembly.

6. A boom assembly according to any one of claims 1 to 5, and further comprising double-acting hydraulic rams for pivoting said side sections.

7. A boom assembly according to claim 6, wherein the rams are connected between the central section and the side section via linkages employing damping means for absorbing shock and centrifugal force during use.

8. A boom assembly according to claim 7, wherein the damping means is composed of springs for transmitting thrust and tensile forces from the rams to the sections.

9. A boom assembly according to claim 7, wheren each ram is connected to a threaded rod extending through a fixed mounting on one of the sections and said springs engage between the mounting and washers located by nuts permitting adjustment.

10. An assembly according to claim 6, 7, 8 or 9, and further comprising guides for guiding parts of the rams for horizontal displacement.

11. An assembly according to claim 7 or 8 wherein the linkages employ means for adjusting the damping force.

1 2. An assembly according to claim 7 or 8, wherein the linkages employ means for adjusting the open and stowed positions of the side sections.

1 3. A boom assembly for crop spraying; said assembly comprising a central section and side sections, each side section being pivotally mounted to the central section for swinging between an open working position aligned with the central section and a stowed collapsed position; wherein double acting hydraulic rams serve to pivot the side sections, the rams being connected between the cental and side sections via linkages employing damping means for absorbing shock and centrifugal force during use.

14. A boom assembly substanially as described with reference to Figs. 2 and 3 of the accompanying drawings.

1 5. A boom assembly substantially as described herein with reference to Fig. 1 as modified by Figs. 2 and 3 of the accompanying drawings.

1 6. A land vehicle provided with a boom assembly in accordance with any one of the preceding claims.