GB2168583A - Counterbalancing of a heater in an agricultural machine - Google Patents

Abstract

An agricultural harvester (2) comprises a relieving device for a header (3) which is pivotable in two planes about a lower pivot point (7). The relieving device serves to reduce travel resistance, soil compaction and skid wear by providing a relieving force which corresponds to the instantaneous ground loading of the header in its operating setting. The relieving device comprises a connecting rod (10) connected by way of a rearward bearing (9) with a feed shaft (1) of the machine. Tension springs (18) are also articulated at the bearing (9). The rod (10) at its forward end carries a pivot lever (12), at which the tension springs (18) and a header coupler (13) are articulated, the coupler (13) being connected to the header. <IMAGE>

Description

SPECIFICATION Counterbalancing of an adapter in an agricultural machine The present invention relates to an agricultural machine and has particular reference to counterbalancing of an adapter in an agricultural harvesting machine, such an adapter being pivotable in two dimensions for adaptation to the contours of the ground. Such an adapter is used by, for example, a combine harvester.

In order that adapters, in particular cutting mechanisms, provide a cut as closely as possible above the ground surface the adapters are guided on the soil by means of skids which copy the ground contours. In the case of, in particular, an adapter of great operating width, it is necessary for the adapter to follow the contours in the plane along the direction of travel and also in a plane transversely to the direction of travel. In this case, it is generally necessary that the load by which the adapter presses on the soil is as small as possible for the prevention of soil compaction, high wear of the skids and high travel resistances.

To achieve low soil loading, different solutions for the relief of the adapters in their movement in the direction of the ground have arisen.

One solution is disclosed in DE-GM 66 05 471. Here, the reduction in the soil loading takes place through a tension spring system, which is guided in an auxiliary frame, between the basic implement and the pivotable feed shaft of the basic implement, to which the adapter is firmly coupled. This solution has certain disadvantages. For one thing, the spring system must be designed to be very strong and thereby heavy, since in addition to the adapter, the feed shaft must also be supported. Moreover, an optimum soil loading is obtained in only one setting of the adapter.

On raising or lowering of the adapter during copying of the ground contours, the soil loading changes constantly. This leads to wear of the skids, soil compaction in the region of the skids and high travel resistance.

In DD-PS 94 725 there is disclosed an adapter which at its base is pivoted to a feed shaft of the basic implement and at the top is guided by way of a pendulating and displaceable auxiliary frame. Tension springs, which are articulated at the feed shaft, are hooked to the auxiliary frame for reduction in the soil loading. In this solution, the adapter mass needs to be absorbed only in part. However, just as in the case of DE-GM 66 05 471, the soil loading of the adapter changes according to its setting during the pendulation in the plane along the direction of travel. Consequently the afore-mentioned disadvantages are still present. The difficulties in both solutions are due to insufficient scope for adaptation of the relieving force to the actual soil loading of the adapter, or adapter and feed shaft, in consequence of the copying of the ground contours.

A further disadvantage of the relieving device of DD-PS 94 725 is that, during the lifting of the adapter into its highest setting, which is far above the operating range and may be required for transport purposes or for setting down or taking up the adapter on or from a transport carriage, additional assemblies are required for the holding of the adapter at the feed shaft.

There is thus a need for a relieving device for adapters, which may be able, in the entire operating range of the adapter, to ensure a relatively low and constant ground loading and thereby only a small amount of soil compaction, low travel resistance and low wear of ground-engaging skids. Such a device should preferably be capable of economic manufacture and of universal use for different adapters. Moreover, it would be desirable to reduce the effort for the guidance of the adapter in its highest setting.

According to the present invention there is provided an agricultural machine provided with an adapter mounted in a lower region of the machine to be pivotable in two dimensions and with counterbalancing means to counterbalance pivoting movement of the adapter in one such dimension, the counterbalancing means comprising a connecting rod pivotably connected at one end thereof to mounting means on the machine, a pivot lever pivotably connected to the other end of the rod, at least one tension spring pivotably fastened at one end thereof at the mounting means and at the other end thereof to the lever, and a coupling arm pivotably coupling the lever to the adapter and extending generally parallel to the line of action of the or each spring.

In a preferred embodiment the adapter is pivotable in two planes about a lower pivot point at the machine or at a feed shaft of the machine and a relieving force is provided to exactly follow the course of ground loading of the adapter in an operational setting thereof, this force also holding the adapter in its highest setting at the feed shaft without additional assemblies. The connecting rod is pivotably received in a bearing at the machine or at the feed shaft and at the other end is connected by way of a pivot pin with the lever. One or more tension springs and the coupling arm are pivotably mounted on the pivot lever, the tension spring or springs being pivotably fastened at the bearing and the arm extending in about the longitudinal direction of the tension spring or springs.The counterbalancing means is preferably arranged at the machine or the feed shaft thereof at a spacing from the pivot point in a plane along the direction of travel.

Expediently, the or each tension spring is connected to a swingletree and the swingle tree is articulatedly connected to the lever. For adaptation of the relieving force to different adapters, it is also expedient if the swingletree or the tension spring has a bearing pin which is displaceable in the pivot lever by, for example, a threaded spindle, about radially of the pivot pin.

For exact adaptation of the linear relieving force of the tension spring to the non-linear ground loading, the bearing pin of the swingletree or the tension spring has a greater radial spacing from the pivot pin than the articulation of the coupling arm, while that bearing pin, the pivot pin and the articulation of the arm in the lever are disposed at the apices of a triangle.

In such a machine embodying the invention there is thus provided counterbalancing or relieving means for an adapter pendulating in two planes, by which the ground loading can be kept low over an entire operating range of the adapter. Thereby, the wear at the groundengaging skids can be reduced, soil compaction lowered and travel resistance reduced, which results in a saving in fuel. Through resetting of the tension spring or springs at the lever, the universal use for different adapter may be possible without reconstruction. Moreover, additional assemblies for holding the adapter at the machine or feed shaft thereof during lifting-out are not necessary.

An embodiment of the present invention will now be more particularly described by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a kinematic diagram of a cutting mechanism and relieving device in an agricultural machine embodying the invention; Fig. 2 is a view of the relieving device in a relieved state; and Fig. 3 is a view of the relieving device in a fuily loaded state.

Referring now to the drawings, there is shown an adapter 3 which is mounted on a feed shaft 1 of a machine 2, for example a combine harvester. The feed shaft 1 is in that case pivotably mounted at bearing points 4 on the basic machine 2. For pivotation of the feed shaft 1, two hydraulic piston-cylinder cylinder units 5 are articulated between this and the machine 2. The adapter 3, in this embodiment a cutting mechanism with a blade 6, is coupled by way of a pivot point 7, permitting pivotation in two planes, with the feed shaft 1 at its rear lower middle region. Moreover, the adapter 3 has a rearward frame 8 extending in an approximately vertical plane. A bearing 9 is disposed centrally on the upper side of the feed shaft 1 at its end near the basic machine. A coupling rod 10 is pivotably received in the bearing 9.A pivot lever 12 is articulatedly connected by way of a pivot pin 11 with the rod 10 at the front end at the side of the adapter. The lever 12 is of triangular shape, with the pivot pin 11 disposed in one corner. An adapter coupler 13 is articulated in a corner facing the bearing 9. A bearing pin 15, through which a threaded spindle 16 supported in the pivot lever 12 is guided, is displaceably received at the remaining corner in an elongate hole 14 extending approximately radially of the pivot pin 11. The bearing pin 15, in all settings, thus has a greater spacing from the pivot pin 11 than the articulation of the adapter coupler 13. Articulated at the bearing pin 15 is a swingletree 17, in the head part of which two tension springs 18 are secured by threaded fastening means one beside the other. The tension springs 18 are hooked at their other ends in a bracket 19 at the bearing 9.The adapter coupler 13 extends from the articulation at the lever 12, in prolongation of the connecting line to the bearing 9, forwardly to the frame 8 of the adapter 3, where it is articulatedly retained by a retaining pin 20.

During copying of the ground contour in the plane along the direction of travel, the adapter 3 carries out a pivotal movement about the pivot point 7, which at the adapter coupler 13 corresponds to a reciprocating movement in about the longitudinal direction of the relieving device. The number of the tension springs 18 and the bias thereof is so selected that a minimum soil loading of the adapter arises in the operational setting of the adapter. This loading changes through the pivotation around the pivot point 7, since the centre of gravity of the adapter 3 displaces relative to the pivot point. This loading results in a curve with respect to the pivotal path or lifting-out path.

During pivotation and by way of the adapter coupler 13 of the relieving device, the pivot lever 12 is reset simultaneously, whereby the relieving force of the tension springs 18 changes. Through the described articulation of the adapter coupler 13 and the tension springs 18 to the lever 12, it is possible to adapt the linear relieving force of the springs to the instantaneous ground loading. In the case of pendulation of the adapter 3 transversely to the direction of travel, the loading does not change, since the relieving device can follow this movement through the sole rear bearing 9 at the basic machine without a displacement of the lever 12 taking place. It is in this case preferable for the spacing between the articulation of the adapter coupler 13 at the adapter 3 and the bearing 9 to amount to a multiple of the possible pendulum deflection transversely to the direction of travel of the adapter 3 at the articulation of the adapter coupler 13. On lifting of the adapter 3 into its highest setting, its centre of gravity redisposes so far rearwardly beyond the pivot point 7 that the relieving force predominates above a certain height of lift above the operating range. Thereby, the adapter 3 is pulled towards the basic machine or the feed shaft thereof.

Claims (6)

1. An agricultural machine provided with an adapter mounted in a lower region of the machine to be pivotable in two dimensions and with counterbalancing means to counterbalance pivoting movement of the adapter in one such dimension, the counterbalancing means comprising a connecting rod pivotably connected at one end thereof to mounting means on the machine, a pivot lever pivotably connected to the other end of the rod, at least one tension spring pivotably fastened at one end thereof at the mounting means and at the other end thereof to the lever, and a coupling arm pivotably coupling the lever to the adapter and extending generally parallel to the line of action of the or each spring.

2. A machine as claimed in claim 1, wherein the or each spring is connected at said other end thereof to a connecting element which is articulated to the lever.

3. A machine as claimed in either claim 1 or claim 2, wherein the or each spring is pivotably fastened to the lever by means of a pivot pin adjustable in position relative to the lever generally radially of the axis of pivotal interconnection of the rod and the lever.

4. A machine as claimed in any one of the preceding claims, wherein the or each spring is pivotably fastened to the lever by means of a pivot pin which has a greater spacing from the point of interconnection of the lever and the rod than has the point of interconnection of the lever and the arm, the points of connection of the lever to the arm, the rod and the spring or springs being arranged in the lever in a triangular relationship.

5. A machine as claimed in any one of the preceding claims, wherein the machine comprises a feed shaft and at least one of the adapter and the counterbalancing means is mounted on the shaft.

6. An agricultural machine substantially as hereinbefore described with reference to the accompanying drawings.