GB2065581A - Articulated vehicle - Google Patents

Abstract

A two-parted working machine, e.g. a digger-loader, of which each of the two frame parts 9, 10 has got a wheel set and is coupled to the other part by a central ball joint 13, which permits rotation and tilting of the two frame parts in relation to each other. In addition to being coupled by this central ball joint 13 the frame parts are connected by a lever 14, which is fastened to both frame parts 9, 10 by means of ball joints, which are placed before and after the central ball joint 13. Thereby compressive and tensile forces will be transferred from one frame part to the other at a smaller angle when turning, causing the tendency of turning over to diminish. A bracket 22 serves as fastening for one end of a stabilizer 23, the other end of which is fastened to a spot on the hindmost frame part 9. <IMAGE>

Description

SPECIFICATION Articulated vehicle The invention deals with a two-parted working machine, of which each machine part has got its own wheel set and is coupled to the other by a central joint, which permits rotationv as well as tilting of the two machine parts in relation to each other. Such working machines are designed to travel on uneven ground andhave the advantage, that all the wheel axes can be stiff and stiffly connected to the chassis. The most common of such working machines is the digger-loader, which has a grab mounted at its rear end and a loading shovel on its front part.

In preference to working machines with a solid chassis, e.g. a farm tractor, where a pendulous movement of the front axle in relation to the chassis is possibie to assure that all its four wheels have earth contact, the machine in question has the advantage, that the risk of turning over on uneven ground is less. When not only the terrain is uneven but it is also necessary to make sudden turns, there is still a risk of turning over, since the force attacking the central swivel has a component at right angles to the tangent of the turning curve.

In order to stabilize the working machine of the invention the two machine parts are further connected with one another by means of a pendulum lever. This lever is fastened to each of the machine parts by means of ball joints, which are placed in the centre plane of both machine parts, but so that none of the ball joints are co-axial to the central joint.

By this arrangement the component of force, which is at right angles to the turning curve of the working machine, is deminished; this will be explained in connection with an example of a practical implementation of the invention. During a turn the centres of the two ball joints and of the central joint will form a triangle, which results in the pendulum lever trying to press the two machine parts apart. However, there will still be sufficient movability in the joint between the machine parts to eliminate this pressure, if the distance between the axis of the one ball joint and the axis of the central joint is not made too large.

In the following a more specific description of the invention will be given in connection with an explanation of the drawing.

The drawing indicates Figure 1 Horizontal section of a diggerloader mounted on a known tractor, built up as an ordinary farm tractor.

Figure 2 Horizontal section of a diggerloader mounted on a tractor in accordance with the invention.

Figure 3 Elevation of the digger-loader mounted on a tractor in accordance with the invention.

Figure 4 The hindmost and the foremost of the chassis of the tractor, on a larger scale.

Figure 5 Horizontal section of a tractor in accordance with the invention, showing the reduced momentum of turnover and, Figure 6 on a larger scale, a disc spring used as stabilizer in the tractor, in accordance with the invention.

Fig. 1 shows a horizontal section of a digger-loader (1, 2) mounted on a tractor, that is built up on the same principles as a farm tractor with a stiff rear axle and a front axle, which is suspended in a point of the longitudinal axis of the tractor (C). A triangle (Tr) with the angle points coinciding with the points of support of the rear wheels and the suspension point of the front wheel has been placed on the diagram. On the triangle is indiceted, how the centre of of gravity gradually moves against the point of the triangle, while the machine changes from transport position to having the loading shovel full.

The turning diameter of the tractor shown is approximately 13,30 m.

Fig. 2 shows a horizontal section of a digger-loader (1, 2) mounted on a two-parted (4, 5) tractor with a wheel set (6, 7) each and fixed axles, where the two parts of the tractor (4, 5) are linked and pivotable about a hinged joint (8).

Swinging the two parts of the tractor (4, 5) mutually is made in the usual manner by means of two hydraulic governing cylinders (these are not shown on the diagram).

On the horizontal a square is placed, the corners of which are determined approximately by the supporting points of the wheels; if the tractor must be stable, its centre of gravity must be within this square. It will also be seen, that the centre of gravity does not more appreciably in relation to the supporting line of the side, whether the tractor is in the transport position or the loading shovel is full (Tt, T,).

Besides it will be noticed, that the turning diameter of the tractor is a good deal smaller, viz approx. 10 metres, than that of the traditional farm tractor.

On Fig. 3 an elevation of the tractor in accordance with the invention is shown, on which the principle of the coupling-up (8) of the front part (5) and the rear end (4) of the tractor just may be seen.

Fig. 3 is an elevation showing the bearing chassis of the tractor and the coupling-up (8) on a somewhat larger scale.

The chassis includes a hindmost and a foremost frame (9, 10) with brackets for suspension of the rear axle respectively of the front axle.

The coupling-up between the hindmost and the foremost frame (9, 10) is made up by a ball joint as locating bearing (13) and a under it situated pendulum lever (14), both placed on the longitudinal axis (CL) of the tractor. The locating bearing (13) is fastened to the hindmost and the front frame (9, 10) on brackets (15, 16), protruding from those in the central axis of the vehicle.

The pendulum lever consists in an upper and a lower plate (17, 18), which have been joined around a square profile, so that the plates (17, 18) continue beyond the tube profile (19).

One end of the pendulum lever (14) is fastened to the hindmost frame (9) over a clamp (20) of plate iron under the frame (9) by means of ball joint (20).

The other end of the pendulum lever is likewise fastened to the foremost frame by means of a ball joint, where the ball joint is placed on a bracket (22) of massive plate iron in the central axis of the tractor, and the pendulum lever (14) reaches with its plate ends into the plate and is fastened.

Reckoned in the forward travelling direction of the tractor the pendulum lever has moved some distance past the axis of rotation of the locating bearing C5, so that the axis of rotation (Cp) of the lever has displaced its centre some distance ahead of the locating bearing (13).

Now look at Fig. 5, which shows a horizontal of the tractor during a turn.

If the rear part of the tractor (4), making pendulum movements in relation to the front (5), is wringed, it will put a torsional moment on the front part.

If the pendulum lever (14) and the locating bearing (13) were situated on the same vertical axis, the moment of turn over might be expressed by P x sin v X distance between bearings, where v is the angle between the pendulum lever (14) and the centre axis (C) of the foremost part of the tractor; but as the lever (14) in accordance with the invention, has been extended beyond the locating bearing (13), the angle will be smaller, and the moment of turn over be reduced by the factor sin v' sin v and the stability is increased correspondingly.

In order to give the tractor a more stable motion a stabilizer (23) has been put between the two parts (4, 5) of the tractor. As is seen from the Figs. 3 and 4 the stabilizer (23) is fastened to the outer edge of the hindmost frame (9) and has a direction obliquely forward-down. It is fastened to the front frame (10) of the tractor, viz on the bracket for the pendulum lever (14) on the centre axis (CJ of the tractor. The point of suspension (C3 lies behind the axis of rotation (cos) of the locating bearing in order to achieve the desired effect, viz neutralization of the torsion of the tractor.

A disc spring (23) is used as stabilizer because of its large inner damping; it is seen on figure on a larger scale. Torsion of the tractor-parts (4, 5) in relation to each other is limited by mechanical stops on the disc spring. Essentially the disc spring consists of a cylinder (24), in which the very disc spring (25) is embedded, and a telescopic pole (26).

The one stop (24) is made by a recess (27) in the inner of the cylinder and a stop chock (28) at one end of the telescopic pole (26).

The other stop is simply made when the telescopic pole reaches the bottom (29) of the cylinder (24).

When the two parts (4, 5) of the vehicle wringe in relation to each other, the disc spring (25) is compressed, thereby neutraliz- - ing the torsion.

Claims (4)

1. Two-parted working machine, of which each machine part has got its own wheel set and is coupled to the other by a central joint, which permits the machine parts to rotate and to tilt in relation to each other, characterized by the fact, that the two machine parts further are connected with each other by means of a pendulum lever, which is kept on the centre line of the machine by means of ball joints, which ball joints again are placed so that none of them are co-axial to the central joint.

2. Working machine in accordance with claim 1, characterized by the fact, that the pendulum lever (14) at both ends has got plate-formed prongs, which manage to reach under and over the bearers (20, 22) of the ball joints.

3. Working machine in accordance with claim 2, characterized by the fact, that to the bearer (22) of the foremost ball joint one end of a stabilizer (23) is fastened, while its other end is fastened on a spot (30) of the hindmost machine part, situated over and beside the pendulum lever.

4. An articulated, two-part, vehicle substantially as hereinbefore described with reference to the accompanying drawings.