VARIATOR

Field of Invention

The present invention relates to a variator forming part of a transmission and particularly, but not exclusively, to a combine harvester comprising such a transmission.

Background of invention

For many decades, self-propelled combine harvesters have been used by farmers to harvest a wide range of crops including cereals, maize and oil-seed rape. Typically, a combine harvester cuts the crop material, threshes the grain (or seed) therefrom, separates the grain from the straw, and cleans the grain before storing in an on board tank. Straw and crop residue is ejected from the rear of the machine.

Combine harvesters generally include a feed beater which is mounted for rotation on a substantially transverse axis and serves to tangentially impel crop material into an axial flow processor. In order for the feed beater to be driven at different speeds a transmission is provided. This can be a belt-drive system comprising belts and pulleys wherein at least one of the pulleys is in the form of a variator where the pulley wheel is separated into two halves. The distance between the two halves can be adjusted in order to change the effective diameter of the pulley and hence the ratio of the transmission.

Current variators include a single large spring located on the outside of the overall dimension of the pulleys which takes up additional space. As the spring is located on the outside of the pulleys there is also a risk of a build-up of dust within the space occupied by the spring.

In view of the feed beater variator being typically located near the right-hand front wheel of the combine harvester, variators which take up less space would be desirable. Summary of Invention

It is an object of the invention to provide an improved space-saving feed beater variator for use in a combine harvester.

According to a first aspect of the present invention, there is provided a variator comprising: a first and second pulley having each having respective first and second portions mounted on a shaft; wherein the first portions of the pulleys are axially movable on the shaft and the second portions of the pulleys are axially stationary on the shaft; at least one or more resilient member; at least one rod which connects the axially movable first portions; and an end plate; characterized in that axial displacement of the first portions of the pulleys away from the second portions of the pulleys is resisted by the at least one resilient member which is substantially enclosed within the at least one rod.

A first advantage of the present invention is delivered by the resilient member being located inside the overall dimensions of the pulleys thereby reducing the axial length of the variator resulting in a space saving variator. The present invention also subsequently results in a reduced overall width of the combine.

Furthermore, with the at least one resilient member resisting axial displacement of the first portions of the pulleys away from the second portions of the pulleys (which may be through urging axial displacement of the first portions of the pulleys towards the second portions of the pulleys), power transmission is improved as drive belt slippage is reduced.

The at least one or more resilient member may be an elastically deformable member. Preferably the resilient member is a spring. In an embodiment, there are at least two or more resilient members, each being substantially enclosed within a respective rod.

The at least one rod may be made from metal or the like. The at least one rod may be substantially cylindrical. The end plate may be made from sheet metal or the like. The end plate may contain at least one or more screws.

The present invention further provides a combine harvester having a crop processor including at least one component driven by the variator according to the first aspect.

Preferably, the at least one component is a feed beater.

Brief Description of the Drawings

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a schematic side view of a combine harvester.

Figure 2 shows an exploded view of the feed beater variator.

Figure 3 shows a cross sectional view of the feed beater variator in a fully retracted position.

Figure 4 shows a cross sectional view of the feed beater variator in a fully extended position.

Specific Description

The invention will now be described in the following detailed description with reference to the drawings, wherein preferred embodiments are described in detail to enable practice of the invention. Although the invention is described with reference to these specific preferred embodiments, it will be understood that the invention is not limited to these preferred embodiments. But to the contrary, the invention includes numerous alternatives, modifications and equivalents as will become apparent from consideration of the following detailed description.

Relative terms such as forward, rearward, transverse, lateral, longitudinal and sideways will be made with reference to the normal forward direction of travel of the combine 10 and indicated by arrow F. The terms vertical and horizontal will be made with reference to the level ground 101 upon which the combine 10 is disposed. In other words the Cartesian axes of ‘longitudinal’, ‘transverse’, and ‘vertical’ are made in relation to the frame 12 of combine 10 and are not affected by any slope in the ground. The terms “upstream” and “downstream” are made with reference of the general direction of crop flow along the material conveyance systems described.

Figure 1 illustrates in schematic form the main components of the crop processing system of a combine harvester 10 and will be used to explain the flow of material below. The crop processing system is shown in solid lines whilst the outline profile of harvester 10 is shown in ghost form.

Combine harvester 10, hereinafter referred to as ‘combine’, includes a frame 12 supported on front wheels 14 and rear steerable wheels 16 which engage the ground 101. A driver’s cab 18 is also supported on the frame 12 and houses a driver’s station from where a driver controls the combine 10.

A cutting header 20 is detachably supported on the front of a feeder house 22 which is pivotable about a transverse axis x to lift and lower the header 20 in a conventional manner.

The combine 10 is driven in a forward direction (arrow F) across a field of standing crop 102 in a known manner. The header 20 serves to cut and gather the standing crop material before conveying such as a crop material stream into feeder house 22. An elevator 24, normally in the form of a chain and slat elevator as shown, is housed within the feeder house 22 and serves to convey the crop material stream upwardly and rearwardly from the header 20 to the crop processor designated generally at 26. At this stage the crop material stream is unprocessed.

The crop processor 26 of the illustrated combine 10 includes a pair of axial flow threshing and separating rotors 28 fed by a tangential flow, crop material impelling, feed beater 30, which feed beater 30 is driven by the variator described below with reference to Figs. 2 - 4. It should be appreciated however that alternative types of variator-driven crop processor may be used without deviating from the scope of the invention. For example, the crop processor may instead include a conventional tangential flow threshing cylinder with a plurality of straw walkers for separation. Alternatively, a single axial-flow processing rotor may be employed. Turning back to Figure 1, the feed beater 30 rotates on a transverse axis and comprises crop engaging vanes (not shown) which convey the crop material stream under the beater and into rotor housings 32 which each house one of said rotors 28. It should be appreciated that only the left-hand rotor 28 and housing 32 is shown in Figure 1 whereas the right-hand equivalent is hidden from view.

The rotors 28 are positioned to have a generally longitudinal, or fore and aft, rotation axis which is normally inclined upwardly towards the rear of the combine 10.

Flighting elements (not shown) provided on the front end of each rotor 28 engage the crop material stream which is then conveyed as a ribbon or mat 103 in a generally rearward axial and helical path in the space between the rotor 28 and the rotor housing 32.

Axial flow rotors 28 serve to thresh the crop stream in a front region, separate the grain therefrom in a rear region, and eject the straw residue via a straw discharge chute 34 provided below a rear portion of the rotors 28, the straw falling either directly onto the ground in a windrow 104 as shown, or via a cutting machine such as a straw chopper.

The cutting machine is formed with an inlet for reception of threshed but unchopped cutting material usually straw emanating from such crops as wheat, barley, rye and oats and with an outlet for the chopped material.

Figure 2 shows an exploded view of the arrangement of the variator according to an embodiment of the invention. A first and second pulley 50, 51 have a respective first and second portion 50L, 50R; 51 L, 51 R which are mounted on a shaft 53. Each pulley has a first portion 50L and 51 L which is axially moveable on the shaft 53 and a second portion 50R and 51 R which is axially stationary on the shaft 53. The end plate 54 is also axially stationary on the shaft. As shown in Figure 2, the variator of this embodiment has eight springs 52, each of which is substantially enclosed within a respective rod 55. The number of springs and rods preferably comprises at least two, with all being equally circumferentially spaced about the shaft 53.

Figure 3 shows the variator when in a fully retracted position. A first and second pulley having a first and second portion are slidably mounted on a shaft 53. In this retracted position, the axial displacement of the axially moveable first portions 50L and 51 L of the pulleys 50, 51 from/relative to the second portions 50R and 50R of the pulleys is resisted by the two (of eight) resilient members shown as springs 52 which are substantially enclosed within rods 55. This results in a larger effective diameter of the pulley which results in a reduced velocity of the pulley.

Figure 4 shows the variator when in a fully extended position. A first and second pulley having a first and second portion are slidably mounted on a shaft 53. In this extended position, the axial displacement of the axially moveable first portions 50L and 51 L of the pulleys 50, 51 from/relative to the second portions 50R and 50R of the pulleys is not resisted by the two (of eight) resilient members shown as springs 52 which are substantially enclosed within rods 55. This results in the axial displacement of the axially moveable first portions 50L, 50R from the axially stationary second portions 51 L, 51 R of the pulleys 50, 51 resulting in a smaller effective diameter of the pulley which results in a higher velocity of the pulley.

By incorporating the at least one resilient member within the overall dimensions of the pulley, this results in a space saving variator as the axial length of the variator is reduced leading to a reduced overall width of the combine.

In summary, there is disclosed a variator comprising a first and second pulley each having respective first and second portions slidably mounted on a shaft attached to an end plate. The first portions of the pulleys are axially movable on the shaft, and the second portions of the pulleys are axially stationary. At least one rod connects the axially movable first portions. Axial displacement of the first portions of the pulleys away from the second portions of the pulleys is resisted by at least one resilient member which is substantially enclosed within the at least one rod.

Clearly the skilled person will recognise that various aspects, embodiments and elements of the present application, including as illustrated in the figures, may be arranged in differing combinations, any and all of which may be considered to fall within the ambit of the inventive concept. The invention will be defined by the following claims.