FI72024B - ANORDNING VID S K TREPUNKTSKOPPLINGAR FOER HYDRAULKRANAR PAO EXEMPELVIS TRAKTORER - Google Patents

Description

1 72024

Device for so-called three-point connections, for example for tractor hydraulic cranes - Anordning vid s.k. The present invention relates to a device for so-called three-point couplings for, for example, hydraulic cranes for tractors, which coupling consists of two pivotable bearings pivoting on the tractor and projecting from the support arm and at least one lifting cylinder to place the pair against the ground, with a drawbar fitted between the stand and the tractor at a level above the support arms in addition to attaching the stand at the top.

Three-point couplings are commonly used in tractors in the agricultural field to attach various implements, such as a plow, harrow and the like, to a tractor. It is also possible to connect a crane to said three-point connection for use in a forestry sector.

In standard three-point connections, the implement is lowered to the ground by means of a lifting cylinder. Thus, the implement is not pressed against the ground, but rests against it with its own weight.

If the tool is a crane, this often means that the crane becomes unstable, especially when working sideways and forward.

To move the crane to the transport mode, the crane stand is lifted up and forward towards the tractor cab via a lifting cylinder. The crane boom lowers above the cab roof. In this case, there is a risk that the crane will fall forward in the rear box of the cab, which could result in personal injury. To avoid this, it is known to install a diagonal support or drawbar between the tractor and the crane base. However, this measure has proved insufficient.

2 72024

A known crane structure formed to prevent instability in the working space of a crane is provided with two hydraulic piston cylinders, each of which is fitted to a stand on its own support leg. These piston cylinders can lift the tractor off the ground, causing the weight of the tractor to press the outriggers against the ground. For this purpose, said two piston cylinders must be separately hydraulically controllable. With these tools, the structure becomes stable in its workspace, but at the same time complex and thus also expensive.

The present invention provides a device for the three-point couplings of tractors, which makes the crane connected to the tractor stable in all spaces, both in the working space and in the transport space. In addition, the device is so cheap that the farmer can use it * advantageously with limited possibilities.

The device according to the invention is characterized in that the traction piston cylinder is arranged between the crane base and the tractor in the crane base, preferably at least one attachment point in the middle thereof and at least one attachment point between the two support arms of the three-point coupling. Other features of the invention will become apparent from the subclaims.

The invention will be explained in more detail with reference to the accompanying drawing, in which:

Figure 1 shows a rear view of a tractor with a crane stand connected to a three-point linkage.

Figure 2 is a partially cut-away side view.

Figure 3 shows a top view of the same part of the tractor as Figure 1. The three-point coupling includes the equipment of the tractor 1. Coupling

II

3 72024 consists of two support arms 2, articulated levers 3 mounted on them and at least one lifting piston cylinder (not shown) for raising the support arms. This can raise the support arms 2, but only allow them to lower by lowering.

Attached to the outer ends of the support arms 2 is a crane base 4. This is provided with support legs 5 for placing against the ground when the crane is in its working space. The stand is stabilized by fitting a drawbar 6 between the crane stand 4 and the tractor 1.

The base has two positions, namely the lowered position, which is the working space of the crane and shown in the drawing, and the upturned position, which is the transport space of the crane.

This transport space is provided by raising the support arms 2 and moving the position of the base and thus the drawbar 6 forwards and upwards relative to the working space. In transport mode, the crane boom 7 is moved to a position above the tractor cab so that the crane can take up as little space as possible. This means that the crane will apply a counterclockwise torque to the bearing shaft in the base 4 of the drawbar 6.

In order to increase the stability of the crane according to the invention, the traction piston-cylinder 8 is arranged between the base 4, preferably in the middle thereof laterally and at least one attachment point between the support arms 2. In the preferred embodiment of the invention shown, the cylinder of the traction piston cylinder 8 is fixed to the base 4 while its piston is fixed at one end to the other end of two traction tension receiving members, i.e. chains forming an angle with each other and attached to their own attachment point. Thanks to this arrangement, the lateral stability of the crane is good.

The traction piston cylinder 8 operates as follows. When the crane 4 72024 has been brought into its working position with the outriggers 5 resting on the ground, the traction piston cylinder is activated, so that the angle at which the traction piston cylinder is placed will shift the weight of the tractor to the outriggers 5, which press harder will press harder against the drawbar 6 (which now acts as a pressure rod) and thus against the tractor, which also increases the stability of the crane. When the crane 7 is brought into its transport space, the traction piston cylinder 8 likewise presses the crane base 4 against the traction rod 6, which contributes to the good stability of the crane during transport. In addition, the traction piston cylinder 8 counteracts the counterclockwise torque around the attachment point of the traction rod 6 in the crane base 4, thus preventing the crane from lowering into the driver's cab and causing personal injury and damage to property. Preferably, the length of the traction piston cylinder 8 is chosen so that the piston rod in the crane transport space reaches its maximum pulled out position, where it no longer needs to be loaded with any hydraulic pressure to push the crane down.

The device according to the invention thus achieves several advantages in the structure of a crane which is attached to the three-point coupling of a tractor. The stability of the crane in the work area increases in substantially all sunnis. Safety increases in the crane's transport space, making it impossible for the crane to tip forward. All these advantages are achieved by a structure which is reliable and inexpensive and which is controlled by a single single-acting piston cylinder. This means that the crane stand 4 can be equipped with simple mechanically operated support legs 5, which makes the crane an economically attractive option for, for example, farmers who own land but have not previously had the opportunity to invest in agricultural implements.

The embodiment described above is to be considered only as an example of 5,72024 and many variations are possible within the scope of the following claims. The chain 9 can be replaced by other tensile stress receiving members, such as steel ropes. The chains 9 and the traction piston cylinder 8 can be placed in the opposite direction, whereby the traction piston cylinder is attached to the tractor 1 and the chains to the crane base 4.

Claims (4)

72024 A device for so-called three-point couplings, for example for hydraulic cranes of tractors (1), which coupling consists of two support arms (2) pivotally mounted on the tractor and projecting therefrom and at least one lifting cylinder for raising and lowering the support arms (2). for placing a pair of legs (5) against the ground, between which the drawbar (6) is additionally arranged between the stand (4) and the tractor on a plane above the support arms (2) to fasten the stand (4) at the top, it is known that the drawbar cylinder (8) is 4) and the tractor on a crane stand, preferably at least one attachment point in the middle thereof and at least one attachment point between the two support arms (2) of the three-point linkage. Device according to Claim 1, characterized in that the traction piston cylinder (8) is fastened to at least one traction tension-receiving element (9), which in turn is fastened to a fastening point. Device according to one of the preceding claims, characterized in that the traction piston cylinder (8) is fastened to the crane base (4) and that the traction tension-receiving element (9) is fastened to at least one fastening point between the support arms (2). Device according to Claim 3, characterized in that the traction piston cylinder (8) is fastened at one end to the crane base (4) and that at its other end two traction tension-receiving members (9) emerge at an angle to each other and are fastened to their respective fastening points. 2) in between.