GB1602945A

GB1602945A - Articulated vehicle

Info

Publication number: GB1602945A
Application number: GB24417/78A
Authority: GB
Original assignee: HANOMAG GmbH
Current assignee: HANOMAG GmbH
Priority date: 1978-02-23
Filing date: 1978-05-30
Publication date: 1981-11-18
Also published as: DE2807729A1; ES477989A1; BE874358A; SE7901619L

Description

(54) ARTICULATED VEHICLE (71) We, HANOMAG GESELLSCHAFT MIT BESCHRAENKTER HAFTUNG, a Company organised under the laws of the Federal Republic of Germany, of Hanomagstrasse 9, 3000 Hannover 91, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to articulated vehicles and in particular, though not exclusively, to wheel loaders which comprise two frame sections pivotally interconnected for the purpose of steering by two ball joints positioned one above the other, each ball joint comprising a ball member operatively connected with one frame section and a socket member supported from the other frame section.

In a typical wheeled loader application the front frame section carries the loader shovel and the rear section carries the power unit.

Two main problems arise with vehicles articulated in the above manner.

The first problem is a manufacturing difficulty caused by the requirement to align and match the various parts of the two ball joints. In particular there is a requirement that the various parts of the ball joints are in their correct relative vertical positions, it being understood that failure to achieve this condition can result in a high level of internal stress being imposed on the ball joints. The second problem which is encountered is that the ball joints are subjected to extremely high loads during use of the vehicle and that in conventional articulated vehicle arrangements in which the ball joints are maintained in fixed positions relative to each other during use of the vehicle these loads can result in excessive wear and even damage to the ball joints in response to particularly demanding working conditions.

It is an object of the present invention to provide an articulated vehicle in which the above problems are mitigated.

According to the present invention we provide an articulated vehicle comprising two frame sections pivotally interconnected for articulation about a steering axis by two ball joints positioned one above the other, each ball joint comprising a ball member operatively connected with one frame section and a socket member supported from the other frame section, the socket member of one of the ball joints being vertically movable relative to its respective supporting frame section, and means being provided for limiting said vertical movement so that said one ball joint is capable of reacting nett axial loading imposed on said one ball joint when the frame sections tend to assume a "hogged back" configuration as hereinafter defined.

It will be appreciated that since the socket member is movable it is possible for this movable member to be easily positioned at the correct vertical spacing from the other socket member so that no internal stresses will be introduced into the two ball joints as a result of incorrect vertical spacing of the various parts. This greatly simplifies manufacture of the vehicle since it is not necessary to maintain such accurate control over the correct positioning of the various parts of the ball joints on the two frame sections since any slight inaccuracy can be catered for by the movable socket member.

In the majority of the working applications of an articulated vehicle with two frame sections joined by two vertically spaced ball joints, and in particular in the most demanding working applications, there will be a tendency for the front and rear frames of the vehicle to fold upwards towards each other so that the vehicle tries to assume a "hogged back" configuration.

Thus in an articulated vehicle in accordance with the present invention since the movement of the movable socket is limited so that the ball joint with the movable socket can react any nett axial load which may be imposed on this ball joint when the vehicle tends to assume a "hogged back" configuration this ball joint is therefore in practice capable of taking half of the total axial load imposed on the two ball joints in most working conditions.

In a preferred construction the lower ball joint is provided with the vertically movable socket member, said movable socket member is arranged to be urged upwardly when the vehicle tends to assume said "hogged back" configuration, and means are provided for limiting the upward movement of the movable socket member.

For example, the lower movable socket member may be arranged to be capable of say up to 0.5 mm of upward movement from a datum position occupied by the socket member when the vehicle is parked on level ground, after this small amount of vertical movement has taken place the lower ball joint is capable of taking half of the total axial load imposed on the two ball joints.

Also. since in the above described arrangement the socket member of the lower ball joint has the capability of relative movement, which need not be limited in the downward direction, there is a certain amount of flexibility in the ball joint system as a whole since the various parts are not held rigidly in the same positions during working. This allows the ball joint system to absorb loading more easily and hence reduce wear and lessen the possibility of damage due to some excessive loads.

In a preferred construction the socket member of the lower ball joint is vertically movable within a vertically extending bore in said respective frame member and a stop member in the form of a cover plate is provided at the upper end of the bore, the cover plate providing an abutment for limiting upward movement of the socket member within the bore.

The amount of relative upward vertical movement is preferably made adjustable by positioning a number of shims between the cover plate and the socket member.

One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic representation of an articulated vehicle having front and rear frame sections joined by two vertically spaced ball joints; Figure 2 is a vertical section through the upper ball joint, and Figure 3 is a vertical section through the lower ball joint.

Referring to Figure 1 a vehicle comprises a rear frame section 1 carrying an engine 2 and rear wheels 3 and a front frame section 4 carrying front wheels 5 and a loader 6. The front and rear frame sections are articulated for steering of the vehicle about a vertical axis I--I by two vertically spaced ball joints 7 and 8.

As can be seen from the drawings the front frame section 4 is provided with two vertically spaced bearing supports 10 while the rear frame section is provided with two bearing supports 9.

Referring to Figure 2 it can be seen that a pin 11 is supported from the member 10 via a bush 15. The pin 11 is provided with a head 12 which abuts a ball member 13 carried on the pin, the ball member being located between the head 12 and the bush 15. A slotted nut 17 engages a threaded portion 16 of the pin to locate the pin in position in the socket 15. The nut 17 is locked by means of a tap washer 18.

The part spherical outer surface of the ball member 13 is received within a complimentarily shaped socket member 14. This socket member is held in a recess 19 in the support member 9 by a plate 21 which is secured to the support member 9 by bolts 22.

A sealing ring 30 may be disposed between the support members 9 and 10 to prevent the ingress of dirt into the ball joint. Alternatively annular seals 40 may be relied on solely to seal the joint. The interfaces between the pin 11 and the ball member 13, and the ball 13 and the socket member 14 are lubricated by various drillings 31 fed from a lubrication nipple 32.

It will be appreciated from the above description that there is no provision for relative vertical movement between the various parts of the upper ball joint 7 since the ball member 13 is held in a fixed position relative to the support 10 and the socket member 14 is similarly held in a fixed position relative to the support 9.

Turning now to Figure 3 which shows the lower ball joint 8 many of the constructional details of this joints are the same as the corresponding parts of the upper ball joint 7 and are therefore similarly numbered. The main distinction is that the socket member 14 is not held in a fixed position relative to the support 9 but simply slides in a cylindrical vertically extending bore 23.

As can be seen from Figure 3 there is no control over the downward movement which the socket member 14 can make relative to the support 9 but the upward movement which can be made from a datum position, corresponding to the position occupied by the socket member 14 when the vehicle is parked on a horizontal surface, is limited by a number of shims 28 which are disposed between the upper end of the socket member 14 and a stop member in the form of a cover plate 24 which is bolted at 25 to the support member 9. These shims 28 act against a collar 26 provided on the plate 24.

When the vehicle is assembled in its datum position the socket member 14 occuppies the position in the bore 23 necessary to correspond to the vertical spacing between the two ball members 13 of the two ball joints. This will leave a clearance 27 between the upper surface of the socket member 14 and the lower surface of the collar 26. With the machine-in the datum position most of the clearance 27 is arranged to be taken up by the shims 28 leaving a small distance typically 0.5 mm between the top of the stack of shims 28 and the collar 26. This allows a small amount of upward movement of the socket member 14 from its datum position.

The ball joint arrangement described above in which the socket member 14 of the lower ball joint is vertically movable within the bore 23 gives the various advantages previously described. In particular when the vehicle is being driven with its loader lowered into a pile of material there is a tendency for the front wheels or rear wheels to be raised off the ground so that the front and rear frames of the vehicle tend to fold upwards towards each other so that the vehicle tries to assume a "hogged-back" configuration. This results in the ball member 13 of the lower joint being pushed upwardly towards the support member 9 of the rear frame taking with it the socket member 14 and fully compressing the shims against the collar 26. Thus the lower ball joint is fully capable of transmitting axial loads between the two frame members of the articulated vehicle since the small amount of upward vertical movement of the socket member which is permitted inside the bore 23 is taken up well before the loads on the ball joints imposed by any working condition become excessive or the vehicle has assumed any real or appreciable "hogged back" configuration.

The vehicle also has a tendency to assume a "hogged back" configuration when being driven with the loader laden.

It will be understood that the ball joint arrangements shown in Figure 3 could be modified so that the movable socket 14 slides in a bore in the member 10 and the ball 13 is supported on the pin from the member 9. If such a construction were adopted the movable socket would tend to move downwardly in the bore in the member 10 when the vehicle assumed a "hogged back" configuration and this downward movement would be controlled in the same manner as the upward movement of the socket 14 in the Figure 3 arrangement, whilst upward movement could be left uncontrolled.

Although in the arrangements described above the lower ball joint is provided with the vertically movable socket it is within the scope of the present invention to reverse the arrangement and arrange the upper ball joint to be provided with the vertically movable socket and to hold the socket of the lower ball joint against vertical movement. Also, since the nett axial force on the upper ball joint is in a downward direction when the vehicle assumes a 'hogged back" configuration. if the upperjoint is arranged to have the movable socket the downward movement of this socket from its datum position would be limited in a similar manner to the upper movement of the lower joint socket shown in Figure 3.

WHAT WE CLAIM IS: 1. An articulated vehicle comprising two frame sections pivotally interconnected for articulation about a steering axis by two ball joints positioned one above the other, each ball joint comprising a ball member operatively connected with one frame section, and a socket member supported from the other frame section, the socket member of one of the ball joints being vertically movable relative to its respective supporting frame section, and means being provided for limiting said vertical movement so that said one ball joint is capable of reacting nett axial loading imposed on said one ball joint when the frame sections tend to assume a "hogged back" configuration as hereinbefore defined.

2. A vehicle according to claim 1 in which the vertically movable socket member is movable in a vertical bore in its respective supporting frame section and in which a stop member is provided at one end of the bore to limit vertical movement of the socket along the bore in the direction in which the socket moves when the frame sections tend to assume a "hogged back" configuration as hereinbefore defined.

3. A machine according to claim 2 in which a number of shims are provided between the stop member and said movable socket member, the number of said shims being adjustable to determine the amount of movement which the movable socket member can make towards the stop member.

4. A vehicle according to any one of claims 1 to 3 in which the lower ball joint is provided with the vertically movable socket member, said movable socket member being arranged to be urged upwardly when the vehicle tends to assume said "hogged back" configuration.

5. A machine according to claim 4 when dependent on claim 2 or 3 in which the stop member comprises a cover plate which extends across the tcp end of the bore.

6. An articulated vehicle constructed and arranged substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. the shims 28 leaving a small distance typically 0.5 mm between the top of the stack of shims 28 and the collar 26. This allows a small amount of upward movement of the socket member 14 from its datum position. The ball joint arrangement described above in which the socket member 14 of the lower ball joint is vertically movable within the bore 23 gives the various advantages previously described. In particular when the vehicle is being driven with its loader lowered into a pile of material there is a tendency for the front wheels or rear wheels to be raised off the ground so that the front and rear frames of the vehicle tend to fold upwards towards each other so that the vehicle tries to assume a "hogged-back" configuration. This results in the ball member 13 of the lower joint being pushed upwardly towards the support member 9 of the rear frame taking with it the socket member 14 and fully compressing the shims against the collar 26. Thus the lower ball joint is fully capable of transmitting axial loads between the two frame members of the articulated vehicle since the small amount of upward vertical movement of the socket member which is permitted inside the bore 23 is taken up well before the loads on the ball joints imposed by any working condition become excessive or the vehicle has assumed any real or appreciable "hogged back" configuration. The vehicle also has a tendency to assume a "hogged back" configuration when being driven with the loader laden. It will be understood that the ball joint arrangements shown in Figure 3 could be modified so that the movable socket 14 slides in a bore in the member 10 and the ball 13 is supported on the pin from the member 9. If such a construction were adopted the movable socket would tend to move downwardly in the bore in the member 10 when the vehicle assumed a "hogged back" configuration and this downward movement would be controlled in the same manner as the upward movement of the socket 14 in the Figure 3 arrangement, whilst upward movement could be left uncontrolled. Although in the arrangements described above the lower ball joint is provided with the vertically movable socket it is within the scope of the present invention to reverse the arrangement and arrange the upper ball joint to be provided with the vertically movable socket and to hold the socket of the lower ball joint against vertical movement. Also, since the nett axial force on the upper ball joint is in a downward direction when the vehicle assumes a 'hogged back" configuration. if the upperjoint is arranged to have the movable socket the downward movement of this socket from its datum position would be limited in a similar manner to the upper movement of the lower joint socket shown in Figure 3. WHAT WE CLAIM IS:

1. An articulated vehicle comprising two frame sections pivotally interconnected for articulation about a steering axis by two ball joints positioned one above the other, each ball joint comprising a ball member operatively connected with one frame section, and a socket member supported from the other frame section, the socket member of one of the ball joints being vertically movable relative to its respective supporting frame section, and means being provided for limiting said vertical movement so that said one ball joint is capable of reacting nett axial loading imposed on said one ball joint when the frame sections tend to assume a "hogged back" configuration as hereinbefore defined.