GB2023399A - Connecting agricultural appliances to a tractor - Google Patents

Abstract

A connection between a tractor three-point suspension and an agricultural appliance is such that, in the working position the appliance may pivot about an axis 2 relative to the tractor but that with the appliance lifted, the appliance is held in a selected position with its lengthwise axis in the travel direction or oblique to this direction. For this purpose there are abutments 9, 10 which engage on lifting the appliance including an abutment 13 which is pivoted about a horizontal axis to swing between operative and inoperative settings in the former of which settings the appliance is held obliquely. The connection may also be arranged so that the abutment may be moved by a mechanism allowing the required setting to be pre-selected. <IMAGE>

Description

SPECIFICATION Arrangement for connecting agricultural appliances to a tractor This invention relates to arrangements for connecting agricultural appliances, that is agricultural machines and implements, to a tractor by means of a three-point suspension which enables an appliance to be raised from a working position to a transport position in which the appliance is clear of the ground, e.g. for conveyance over roads.

In some cases, the connection between the appliance and three-point suspension allows swinging of the appliance about a vertical axis so that in the working position the appliance tracks properly when travelling around curves.

It is clearly undesirable with such form of connection that the appliance should be able to swing about the vertical axis when in the carrying position.

In our patent application No. 12913/78 there is described and claimed a form of connection for use between a three-point suspension and an appliance, which connection is of the class (referred to herein as the class specified) including a pivot allowing swinging of the appliance about a vertical axis, and which connection is such that, when the appliance is lifted into the transport position, the appliance is automatically constrained to take up a selected position and is prevented from swinging from that position.

This effect is achieved by providing a second pivot extending transversely to the travel direction which allows the appliance to swing about a horizontal axis under its own weight as it is lifted and by further providing abutments which in the working position are spaced apart but on lifting the appliance come into engagement due to pivoting of the appliance about the horizontal axis and thereby constrain the appliance to take up the selected position.

In one arrangement described in our above patent application No. 12913178 the abutments are arranged so that, in the selected position, the longitudinal axis of the appliance may either extend in the travel direction or oblique to it. Forthe latter purpose, there is an abutment of adjustable length to one side of the vertical axis, which abutment is movable between operative and inoperative settings by being pivoted on a vertical axis. In the inoperative setting, the adjustable length abutment projects laterally outwards. Although the arrangement functions reliably, it is found that when safety guards are to be provided problems arise firstly due to the large size of the guard and secondly due to interference by the guard with the mobility of the appliance.

The invention deals with these problems and provides laterally of the vertical axis an abutment which is pivoted about a horizontal axis to swing fore and aft whereby the transverse width of the connection is substantially unaffected and the provision of guards is facilitated, especially as the pivoted abutment may be close to the chassis of the appliance.

The pivoted abutment may, according to a feature of the invention, be arranged for remote actuation, and there may be means to pre-set the pivoted abutment for subsequent pivotal movement to the desired setting.

In one particular construction, the pre-setting means includes a selector actuation of which biasses the pivoted abutment to pivot in one direction or the other. The biassing means comprises a spring or springs in a cylinder, which is pivoted to the pivoted abutment and a piston in the cylinder between the ends of the spring or between the springs such that, on operation of the selector, the piston is moved to stress the spring or springs so loading the cylinder in one direction or the other and correspondingly biassing the abutment, which conveniently may be an adjustable length strut.

With this particular construction, the abutment can be biassed towards its operative setting to which it moves when the tractor vehicle travels round a bend. When the abutment is in its operative setting holding the raised appliance in an oblique travelling position, the abutment may be biassed towards its inoperative setting to which the strut moves following lowering of the appliance.

One embodiment of tracking device of the invention, by way of example, is illustrated in the accompanying drawings in which:- Fig. lisa part-sectional side elevation of the embodiment in the working position, Fig. 2 is a plan view of Fig. 1, Fig. 3 is a view corresponding to Fig. 1, but with the tracking device in the transport position, and Fig. 4 is a plan view of Fig. 3.

In Figs. 1 to 4, the chassis 1 of an agricultural implement (not shown) is connected in a manner explained in greater detail below with a three-point frame 3 which in use is connected with a tractor three-point lift device (not shown).

The implement chassis 1 is mounted for pivoting about a stationary, vertical spindle 2 which is articulated at its upper end to the three-point frame 3 through a horizontal spindle 4 extending transversely of the direction of travel. The lower end 5 of the vertical spindle 2 carries a roller 5' which is guided for movement in the longitudinal direction of the implement in a slot 6 of a plate 7 rigidly connected with the three-pointframe 3.

Near the lower end of the vertical spindle 2, a transverse member 8 is fixed on the chassis 1 and this member 8 has an abutment roller 9 on each of its free ends to either side of the pivot spindle 2. The pivoting movement of the implement chassis 1 about the spindle 2 thus be limited by the rollers 9 abutting an abutment plate 10 which extends transversely of the direction of travel and is secured to the frame 3. The rollers 9 can be of steel, synthetic plastics or cast material. The upper link of the threepoint lift device in use is articulated to a bore 11 in the frame 3.

The position of the implement chassis 1 in Figs. 1 and 2 corresponds to the working position of the implement. In travelling round bends the implement can pivot about the vertical spindle 2 to an angle extent determined by abutment of the rollers 9 on the plate 10.

If the implement as so far described is lifted by means of a three-point lift device, the implement chassis 1 pivots under its own weight about a horizontal spindle 4 in the clockwise direction until one roller 9 abuts the stop plate 10. Thereafter the chassis turns about spindle 2 until the other support roller 9 also rests on the stop plate 10. In this position the implement chassis 1 is in a position in which its longitudinal axis is parallel with that of the tractor.

With some agricultural implements it is undesir ablethatthe longitudinal axis of the implement chassis should be parallel with that of the tractor when in the transport position. For example a rotary haymaker having a laterally protruding transverse beam carrying the tined wheels often exceeds the permitted transport width, and for transport purposes the transverse beam must be oblique to give a smaller transport width.

For this purpose a locking mechanism is provided by which the implement chassis can be held for transport in such an oblique position.

The locking mechanism consists of an abutment in the form of a strut 13 which is pivoted on the chassis 1 to rotate about a horizontal spindle 14, and to vary the effective length of the strut a set screw 15 is screwed into its end remote from spindle 14.

Acylinder 16 is pivoted on the strut 13 between its ends by means of a horizontal pin 17. The cylinder houses a helical spring 18 bearing by its ends on the ends of the cylinder. A piston rod 19 extends through an opening 20 in one end of the cylinder and carries a piston 21 approximately at the middle of the spring 18.

A lever 22, to which the rod 19 is pivoted, is pivoted on the chassis 1 to turn about a horizontal pivot 23 and a catch device 24 is provided by which the lever can be held in different positions. The cylinder and springs constitute biassing means for the strut, and the piston and lever constitute a selector for pre-setting the sense of the spring bias.

By turning the lever 22 about the spindle 23 in one direction or the other, the strut 13 is caused to pivot in the corresponding manner about its pivot axis 14.

If however the strut 13 is prevented from pivoting, as when the set screw abuts the stop plate 10, then the cylinder 16 also cannot move and the piston 21 moves in the cylinder so compressing either the left orthe right section of the helical spring 18 to bias the strut for subsequent movementto a selected setting.

When the implement chassis is to be locked in the oblique position for transport (Fig. 4), the lever 22 is moved counter-clockwise thereby through the piston rod 19, the helical spring 18 and the cylinder 16, pivoting the strut 13 until the set screw strikes the stop plate 10. Thereafter the further pivoting of lever 22 compresses the left hand section of spring 18. The lever is latched in this position by means of the catch device 24.

Now when the tractor turns to the right, the implement chassis 1 assumes the oblique position and the set screw 15 tends to move from contact with plate 10. However such contact is maintained due to rotation of strut 13 counter-clockwise under the influence of the compressed section of spring 18 and ultimately the strut reaches a horizontal position in which the head of the set screw 15 rests flat against the stop plate 10. The transverse member 8 is thus locked against turning towards the position of Fig. 1, and on lifting of the three-point frame 3, the implement chassis 1 is maintained in this position.

To return to the working position, the lever 22 is turned clockwise so that the right hand section of spring 18 is compressed and the lever is latched by the catch device 24. On lowering of the implement chassis 1, the strut is relieved of load and it can be pivoted in the clockwise direction into its vertical position due to the compressed section of spring 18 urging the cylinder 16 to the right.

Thus the locking mechanism works semiautomatically, that is to say (a) the lever 22 can be set for locking irrespective of the position of the implement chassis and the strut 13 will automatically take up the locking position on travelling round a righthand bend and (b) the lever can be set for unlocking at any time and the strut will be released on lowering of the implement chassis. The fact that the lever 22 can be actuated in the direction of locking or unlocking in every position of the implement chassis, and the corresponding movement of the strut 13 takes place only at a subsequent moment, has the consequence that the rotation of the lever can be carried out without great application of force because it is only necessary to initially stress the helical spring 18.

Therefore the lever can be actuated from the tractor seat through a linkage or a cable, without great technical expense.

In the above description of the example of embodiment as represented in the drawing the basis was adopted that the helical spring 18 is a one-piece spring. The invention can however of course also be realised in a manner in which in place of a continuous helical spring there are arranged two helical springs acting in opposite directions on the piston 21.

Claims (8)

1. A connection of the class specified, wherein there is a second pivot extending transversely to the travel direction to allow the appliance to swing about a horizontal axis under its own weight as it is lifted, and abutments which in the working position are spaced apart and on lifting of the appliance come into engagement due to swinging of the appliance about the horizontal axis thereby constraining the appliance to take up a selected position, one of the abutments being to one side of the vertical axis and being pivotable about a horizontal axis to swing fore and aft between operative and inoperative settings constraining the appliance when lifted to positions respectively oblique to and in line with the travel direction.

2. A connection according to claim 1 wherein the pivoted abutment is arranged for remoted actuation.

3. A connection according to claim 1 or claim 2, wherein means are provided to pre-setthe pivoted abutment for subsequent pivotal movement to the required setting.

4. A connection according to claim 3, wherein the pre-setting means includes a selector actuation of which biasses the pivoted abutment to pivot in one direction or the other.

5. A connection according to claim 4, the bias sing means comprising a spring or springs in a cyli nder pivoted to the pivoted abutment and a piston in the cylinder between the ends of the spring, or between the springs, such that on operation of the selector, the piston is moved to stress the spring or springs so loading the cylinder in one direction or the other and correspondingly biassing the a but ment.

6. A connection as claimed in claim 4 or claim 5, wherein the selector is a lever positioned remotely from the abutments.

7. A connection according to any of claims 1 to 6, the pivoted abutment being an adjutable length strut.

8. A connection of the class specified substantially as hereinbefore described with reference to and as shown in the accompanying drawings.