The present invention relates to an improved implement and vehicle incorporating the implement. More particularly, but not exclusively, the present invention relates to an implement for a tractor which has a pivotally connected front steering assembly.

Recently a new range of tractors has been developed, such as the new Holland TNF range, in which the entire front steering assembly pivots with respect to the body of the tractor. This provides enhanced turning capabilities for the tractor but poses problems in mounting implements, such as a forklift, to the tractor.

According to one proposa a forklift may be mounted to this type of tractor using side bars connected to the body of the tractor. This solution has the problem that the turning capabilities of the tractor may be restricted and that the load may not be ideally located for each position of the steering assembly.

It is an object of the present invention to provide an implement and a vehicle incorporating the implement which overcomes these drawbacks or which at least provides the public with a useful choice.

According to a first aspect of the invention there is provided a vehicle and a vehicle implement comprising : a vehicle having a steering assembly including a steering frame having wheels at either end thereof, wherein the steering assembly is pivotally connected to the body of the vehicle ; an implement secured to the steering assembly ; and

linkage means extending between the implement and the vehicle adapted to maintain a desired inclination of the linkage as the steering assembly turns with respect to the body of the vehicle.

According to a first embodiment the linkage means includes guide rail describing an arc of rotation of the steering assembly secured to the vehicle and a roller engaging the rail secured by a linkage to the implement. Preferably the roller is secured via an hydraulic ram to the implement.

According to a second embodiment the linkage means is a variable length linkage pivotally connected at one end to the vehicle and at the other end to the implement. The variable length member is preferably an hydraulic ram. The extension of the hydraulic ram may be adjusted by a vaive coupled to the steering assembly to compensate for the required changes in length as the steering assembly rotates.

According to another aspect of the invention there is provided An implement suitable for use with a vehicle having a steering assembly including a steering frame having wheels at either end thereof in which the steering frame is pivotally connected to the body of the vehicle, the implement including : securing means for enabling the implement to be secured to the steering frame ; and linkage means secured to the implement at one end and adapted to be secured to the vehicle at the other end, the linkage means enabling, in use, a desired inclination of the implement to be maintained whilst the steering assembly turns with respect to the body of the vehicle.

According to a further aspect there is provided linkage means for connecting an implement to a steering frame of a vehicle which is pivotally connected to the body of the vehicle, the linkage means including :

a guide rail adapted to be secured to the vehicle and having a portion describing an arc of rotation of the steering frame ; and a linkage having means for pivotally securing the linkage to an implement at one end and a roller adapted to engage the guide rail at the other end.

According to a further aspect of the invention there is provided linkage means for connecting an implement to a steering frame which is pivotally connected to the body of the vehicle, the linkage means including : a variable length linkage having means for pivotal attachment to the vehicle and implement at either end ; and control means which, in use, drives the linkage to adjust its length in dependence upon the position of the steering frame relative to the vehicle body.

The invention will now be described by way of example with reference to the accompanying drawings in which : Figure 1 : shows a side view of a tractor incorporating a forklift according to a first aspect of the invention.

Figure 2 : shows a plan view of the tractor and forklift shown in figure 1.

Figure 3 : shows a detailed view of the rot ! er engaging the guide.

Figure 4 : shows a tractor incorporating an implement mounting arrangement according to a second embodiment.

The invention will now be described by way of example with reference to a forklift attached to a tractor. It is to be appreciated that the present invention may find application for a wide range of imptements connected to a wide range of vehicles.

Referring to figures 1 to 3 there is shown a tractor 1 having a fork lift 2 connected thereto. Tractor 1 is of the type in which steering assembly 3

pivots about pivot point 4 of tractor body 5. Wheels 6 and 7 are pivotally connected at either end of steering frame 8 of steering assembly 3.

The steering assembly utilise in this tractor enables the tractor to complete very tight turns. The arrangement poses the problem that structures projecting from the front of the tractor may obstruct turning of the steering assembly. A typical fork lift arrangement in which the forklift projects from the front of body 5 would interfere with the steering assembly.

In the present invention fork lift 2 is pivotally secured at a lower securement point 9 to steering frame 8. Steering frame 8 has a section 10 extending upwardly therefrom and having a roller 11 rotatably mounted thereto at an upper end thereof. Roller 11 engages with guide 12 throughout the range of rotation of steering assembly 3. Hydraulic ram 13 is connected via pivotal linkages 14 and 15 to forklift 2 and section 10. Guide means 12 is secured to body 5 of tractor 1 by arms 16 and 17.

Figure 3 shows an enlarged version of roller 11 and guide 12. It will be seen that there is substantial clearance between the upper and lower flanges 18 and 19 of roller 11 and guide 12. This is to allow for movement up and down as the steering assembly rotates throughout its range of movement. Roller 11 may also be able to tilt about its longitudinal axis relative to section 10 so as to closely follow the path of guide 12.

In use, fork lift 2 is positioned relative to tractor 1 so that roller 11 engages with guide 12 and the forklift may be secured to tractor 1 at lower attachment point 9 via pins. Forklift 2 is thus rigidly secured to steering frame 8 at lower attachment point 9 and pulley 11 is engaged with guide 12.

During turning steering assembly 3 is rotated about pivot point 4 and ro) ! er 11 moves from one end to the other of guide 12. Roller 11, portion 10, ram 13 and guide 12 prevent forward tilting of forklift 2.

Forklift 2 is connected to an hydraulic line from tractor 1. Ram 13 is also connected to an hydraulic line from tractor 1. Quick connect hydraulic fittings may be provided at a suitable location on tractor 1 so that lines from forklift 2 and ram 13 may be easily connected during installation.

In use, hydraulic ram 13 may be extended or retracted to tilt the forklift about lower securement point 9. Forks 20 of forklift 2 may be hydraulically driven up and down in the normal manner.

It will be appreciated that as the steering assembly moves about pivot point 4 the forklift 2 will be well located to carry the load in a stable manner without tipping tractor 1.

It will also be appreciated that a tractor may be designed to incorporate guide 12 within the design of the tractor so that guide 12 follows the front profile of the tractor and can be secured at suitable securement points at the front of the tractor.

Referring now to figure 4 an alternative embodiment is shown. Like integers have been given like numbers for ease of explanation. In this embodiment portion 10, rollier 11, guide 12 and arms 16 and 17 have been done away with. Instead ram 13 is simply connected via pivotable connection 15 to body 5 of tractor 1. Accordingly, as steering assembly 3 pivots from one side to the other, pivotal connection 15 allows ram 13 to rotate with respect to body 5.

In this embodiment ram 13 must extend as the steering assembly rotates to the extremes of its turning circle and retract as the steering assembly comes back to the straight ahead position to maintain a relatively constant

inclination of forklift 2. This variation of ram 13 may be controlled by an hydraulic valve 21 coupled to steering assembly 3.

Hydraulic valve 21 is connected via linkage 28 to steering assembly 3 and receives hydraulic fluid and returns it via lines 22 and 23 connected to the hydraulic system of the vehicle. Lines 24 and 26 are connected via quick connect hydraulic fittings 26 and 27 between valve 21 and ram 13. As the position of steering assembly 3 changes relative to vehicle 1 valve 21 adjusts the supply of hydraulic fluid to ram 13 to alter its length and maintain the desired inclination.

Alternatively, a control means may monitor the position of steering assembly 3 and adjust the extension of ram 13 accordingly. This is a mechanically simpler implementation although it requires more sophisticated control apparatus. It will be appreciated that alternate ajustable length linkages, such as electromechanical linkages, could be employed.

A user can adjust ram 13 to tilt the forklift 2 forward or back in the usual way. As pivotal connection 15 is provided at the front of the vehicle a user may still easily access under the bonnet of the vehicle. As the pivotal connection 15 is relatively forward and low good stability is also maintained.

The present invention thus provides an implement for a tractor having a pivoting steering assembly that does not interfere with vehicle turning and distributes load so as not to destabilise the vehicle.

Where in the foregoing description reference has been made to integers or components having known equivalents then such equivalents are herein incorporated as if individually set forth.

Although this invention has been described by way of example it is to be appreciated that improvements and/or modifications may be made thereto without departing from the scope of invention as set out in the appended claims.