Ground attitude control means

Details Ground attitude control means Ground attitude control means

1999-08-18

2001-05-22

Douglas, Lisa Ann (Department: 3752)

Fluid sprinkling, spraying, and diffusing

With mobile tank-type supply means

Spray boom or bar type distributor

C239S166000, C239S172000

Reexamination Certificate

active

06234407

ABSTRACT:

TECHNICAL FIELD
This invention relates to a ground attitude control means more particularly, but not exclusively, for use in agricultural crop-spraying equipment.
BACKGROUND ART
It is common practice to apply chemicals to a growing crop, for instance to help control pests, fungi or weeds.
Ground-based crop-spraying equipment commonly comprises a vehicle-carried body, e.g. a tractor-carried body, having an elongate framework or boom which extends laterally from the body and which supports nozzles which apply a spray mist of chemical/water mixture to the crop and its surroundings. Such a boom is often used to cover working width of between 12 and 30 meters to minimise the number of passes required to cover a given area of land.
The requirement for such an elongate boom causes the designer of crop-spraying equipment many problems in dealing with the stresses imposed on the boom and its supporting framework and on the carrying vehicle. There is also the problem of maintaining a distance between the boom and the ground (or growing crop) whilst the carrying vehicle is travelling over uneven ground.
Prior types of equipment have attempted to resolve the problems using various mechanisms.
Previous designs are known which use a single pivotal connection between a carrying frame supported on the carrying vehicle and the boom which allows the boom to swing in the manner of a pendulum independently of the carrying frame. With this type of design it is possible for conditions to occur which cause the boom to swing uncontrollably and it is common practice to add springs and shock-absorbers between the carrying frame and the boom to afford some degree of control. This has the effect of tending to make the boom attempt to follow the movements of the carrying frame on the one hand and attempt to follow the horizon on the other hand. The resultant compromise angle is not always desirable.
The addition of springs and shock-absorbers is beneficial in that the boom tends to follow the angle of the carrying frame (rather than following the horizon) when operating on a side-incline (or when the vehicle's wheels on one side are in a deeper rut than on the other side) but also causes an unwanted effect when conditions occur which require the boom to be set at an angle differing to that of the carrying frame. This can commonly occur, for example, when the suspension of the carrying vehicle or frame tends to cause the boom to favour the horizontal rather than following the angle of its wheels.
An alternative known method adds a levelling bar to the above pendulum mechanism to allow the neutral pendulum point (that is where the springs on both sides of the pendulum pivot apply an equal force) to be biased to one side or the other. This allows the machine operator (or an automatic mechanism) to reset the correct distance between boom and ground for the duration of the aforesaid conditions. This mechanism commonly takes the form of a rocker bar pivoted on the carrying frame, the springs being attached to this bar rather than to the carrying frame.
The present invention seeks to provide means to enable the boom more closely to follow the contours of the ground by at least partially isolating the boom from the movements of the carrying vehicle.
An object of the invention is to seek better to isolate the boom from movements of the carrying frame while retaining the beneficial effects of the boom tending to follow the angle of the carrying frame and also retaining the ability to bias the neutral pendulum point.
DISCLOSURE OF THE INVENTION
The invention is ground attitude control means to enable a member, e.g. an elongate boom, to maintain a constant attitude with respect to a datum, e.g. the ground, comprising a carrier on which the boom is pivotally mounted for movement about a substantially horizontal axis, a levelling member pivotally mounted on the boom for movement about a substantially horizontal axis and linkage means pivotally connected between the levelling member and the carrier, the pivotal connections being disposed to cause the boom to rotate at a lower or higher angular velocity than the carrier in response to rotation of the carrier.
Preferably one or more springs and/or shock absorbers or dampers will be connected between the boom and the levelling member.
The linkage may be in the form of a length adjustable member, e.g. an hydraulic cylinder.
The position at which the linkage is pivoted on the carrier may be adjustable longitudinally of the boom to vary the effect of the control means.
The member to be attitude controlled may be an agricultural spray boom having spray nozzles. Thus in one aspect the present invention provides an agricultural implement having an elongate boom supporting spray nozzles for applying chemicals to a soil surface or growing crop the attitude of the spray boom being controlled by control means as described above.
The pivoting of the levelling member on the boom rather than on the carrying frame, and suitably positioning he levelling member/carrier linkage, results in the production of the desired advantageous geometrical effect. The effect may be enhanced by attaching the shock absorbers between the levelling member and the boom rather than between the carrier and the boom as is conventional. Thus by suitably adjusting the position of the linkage between levelling member and the carrier, the damping effort of the shock absorbers can be altered without changing the shock absorbers themselves.
As the carrier rotates due to rocking of the vehicle, the boom tends to maintain its rotational position due to its own inertia, the shock absorbers and springs (and the fact that the levelling member is pivotally attached to the boom) tend to cause the levelling member to copy the rotational position of the boom but the levelling member is linked to the carrier and so is forced to rotate or contra-rotate relative to the carrier. Thus the springs and shock absorbers cause the boom to rotate or contra-rotate relative to the carrier which tends to neutralise or enhance the effect on the boom of the initial rotational movement of the carrier.
The overall effect is that the boom is caused to rotate at an angular velocity which may be lower or higher or the same as the carrier. By varying the geometrical relationship between the position of the pivots and the angle of the levelling member/carrier linkage it is possible to change the ratio of this effect.


REFERENCES:
patent: 4168800 (1979-09-01), Quick
patent: 4643358 (1987-02-01), Jackson
patent: 41 40 254 A1 (1993-06-01), None
patent: 2 654 574 (1991-05-01), None
patent: 2 701 774 A1 (1993-02-01), None

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