GB2197271A

GB2197271A - Resiliently mounted guide wheel for a tensionable track of a vehicle

Info

Publication number: GB2197271A
Application number: GB08724472A
Authority: GB
Inventors: Gunter Kircher; Uwe Ratz
Original assignee: Dr Ing HCF Porsche AG
Current assignee: Dr Ing HCF Porsche AG
Priority date: 1986-10-18
Filing date: 1987-10-19
Publication date: 1988-05-18
Anticipated expiration: 2007-10-19
Also published as: FR2605283A1; FR2605283B1; GB2197271B; GB8724472D0; DE3635546A1

Abstract

A resiliently-mounted guide wheel (2) for a tension track (1) is mounted on a wall 5 of a vehicle with a rocker member (4). A spring and damper arm 6 is connected to the rocking member 4 and a track tensioner 7 is mounted on a hub 8 of the wheel 2. The rocker member (4) comprises an angled crank with two guide arms (9, 10) having axes of rotation 11 and 2. One guide arm (9) mounted on the wall (5) comprises an eccentric mounting (13) for the damper arm (6). The other guide arm (10) facing the guide wheel (2) is arranged eccentrically to the hub (8) of the guide wheel (2) so as to be rotatable therein. In addition, a further eccentric mounting (14) for the track tensioner (7) is provided on the hub (8). The guide wheel (2) is mounted on the crank guide rod (4) in such a way that the guide wheel (2) performs an adjustment movement from a basic position (G) to a spring-compression position approximately in the direction of travel between the two runs of the track. <IMAGE>

Description

SPECIFICATION Resiliently mounted guide wheel for a tensionable track of a vehicle The present invention relates to a resilientlymounted guide wheel of a track of a vehicle, particularly an armour-plated vehicle.

German Patent 22 19 821 discloses a bearing for a guide wheel of a track of an armourplated vehicle by way of two rockers, which are held so as to be pivotable with respect to one another. One of the rockers is mounted on a side of the wall and is connected to a track tensioner. The other rocker has a mounting for the guide wheel and is provided with a support for a damper arm. During spring-compression such a design with two rockers and their points of articulation requires a guide wheel setting in which there is a reversal to the rear. i.e. opposite to the direction of travel, and a certain "trackless operation" occurs which can be compensated by the track tensioner by positive resetting.In addition, track tensioning is thereby lost in a state of travel which is characterized by "trackless operations", which arise as a result of the usually simultaneous spring-compression of the front rollers. A substantial structural outlay, which requires an additional bearing position between the two rockers, is also necessary in this construction.

An object of the invention is to provide an improved suspension for a guide wheel which will ensure a uniform track tensioning independent of spring-compression, and which will allow the track to be tightened by means via the guide wheel.

This invention provides a resiliently-mounted guide wheel as claimed in claim 1.

As a result of the suspension of the guide wheel on a crank mounted on the side of the wall eccentrically to the hub, a forcible displacement of the guide wheel both takes place approximately in the direction of travel of the vehicle during spring compression and during tensioning of the track. The kinematic arrangement of the guide wheel suspension is such that during the rocking or spring compression of the guide wheel a forward reversal takes place, i.e. approximately in the direction of travel, and so the "trackless operation" otherwise occurring can be compensated to the extent that running conditions are not adversely affected.

In particular, the mounting of the crank on the side of the wall and the damper arm used for the suspension are arranged in such a way that the centre of the guide wheel is arranged approximately in the resultant of the two track runs running up to the guide wheel as seen with respect to the mounting of the steering rod. When the track encounters an obstacle the guide wheel can pivot upwards, in which case a corresponding energy-aborbing capacity is provided by the damper arm.

According to the invention, a track tensioner, which is articulated by way of a pivot bearing directly on the inner stationary part (the hub) of the guide wheel and is supported on the wall, is connected to the crank. In this way it is advantageously possible for the rocking guide wheel to cooperate both with a track tensioner and with an active track tensioner i.e. an active track tensioner can be used to compensate the "trackless operation" occuring during spring compression of the front rollers. The track is tightened in a simple manner by mechanical or hydraulic adjustment of the track tensioner and by turning the guide wheel about the guide arm of the crank.

It is particularly expedient for the crank to be arranged on the side of the wall in front of the axis of the guide wheel. The setting of the crank in the basic position is predetermined by the position of the damper arm. The track tensioner and the damper arm are preferably arranged adjacent each other in the free space between the guide wheel and the wall, and the mounting of the track tensioner on the side of the hub should be moved as close as possible to the vertical longitudinal median plane of the wheel so that the stressing of the mounting on the side of the wall can be kept low.

A stop for the guide wheel during the spring compression may be provided in the damper element and is not formed by a track cover, so that a uniform spring excursion of the guide wheel is provided which is independent of the use of track padding.

Since the tensioning-forces and in particular driving forces during return travel of a reardrive tracked vehicle are absorbed by way of the track tensioner, the mounting of the crank fixed to the wall can be smaller, and this offers the advantage of a small guide wheel and thus a substantial distance of the rocking guide wheel from the contact surface.

An embodiment of the invention will now be described with reference to the accompanying drawing, wherein: Fig. 1 is a diagrammatic view of a resiliently-mounted guide wheel with a crank, damper arm and chain tightener in a basic position without spring compression, Fig. 2 is a diagrammatic view of the guide wheel of Figure 1 in a spring-compression position, Fig. 3 is a section along the line Ill-Ill of Fig.

1, and Fig. 4 is a view of the paths of movement of the guide wheel during track tensioning and during spring compression.

In Fig. 1, the front of a vehicle has a track 1, a guide wheel 2 and a running wheel 3.

The guide wheel 2 is mounted on a wall 5 of the vehicle by means of a rocking member 4.

A spring and damper arm 6 is connected to the rocking member 4 and a track tensioner 7 is mounted on a hub 8 of the guide wheel 2.

The rocking member 4 essentially comprises an angled crank with two guide arms 9 and 10, having axes of rotation 11 and 12, respectively (Fig. 3).

The damper arm 6 is mounted on the wall 5 and is articulated in a bearing 13 at a distance a in front of the axis 11 on the guide arm 9. The track tensioner 7 is likewise mounted on the wall 5 and is connected to the hub 8 by means of a bearing 14 and hoids the hub 8 eccentrically.

In a basic position G (Fig. 1) the axis of the guide arm 10 directed towards the hub 8 and the bearing 14 of the track tensioner 7 on the side of the hub are situated behind a vertical median transverse plane X-X of the guide wheel 2, as viewed in the direction of travel F. The bearing 14 of the other guide arm 9 on the side of the walls and the bearing 13 of the damper arm 6 are situated in front of the vertical median transverse plane X-X of the wheel, as viewed in the direction of travel F.

The bearing 14 of the track tensioner 7 on the side of the hub 8 is arranged at as small as possible a distance C from the vertical median longitudinal plane Z-Z (bearing plane) of the wheel In the space between the wall 5 and the guide wheel 2. Similarly, the mounting 13 of the damper arm 6 and the said arm are situated in this interspace. The mounting 15 of one guide arm on the side of the wall with the axis 11 is arranged in front of the axis of rotation 12 of the guide arm 10 on the side of the hub, as viewed in the direction of travel F. In particular the crank 4 is set in the basic position G at an angle a to a horizontal median transverse plane Y-Y of the wheel, in such a way that this angle is increased in the spring-compression position E to the angle al (Fig. 2).

The track tensioner 7 is arranged in such a way with respect to the crank 4 that the line of action 7a of tne track tensioner 7 is situated under a lever arm b towards the axis 12 of one guide arm 10.

Fig. 4 shows in greater detail how the guide wheel 2 is adjusted during chain tensioning and during spring compression.

The track tensioner 7 is mounted eccentrically on the hub 8 at the bearing 14. The tensioning of the track 1 occurs in accordance with the pattern of the curve 17 when the guide wheel 2 is without spring compression.

in the example iluustrated the track 1 is tensioned for example as far as point 18. During the tensioning the axis 16 of the guide wheel 2 moves on the curved path 19 for example as far as point 20, i.e. forwards in the direction of the arrow 21 as viewed in the direction of travel F. During spring-compression the guide wheel 2 moves forwards obliquely along the line 22 as far as the curved path 19' in the state of spring compression, so that a "trackless operation" is initiated. The track tensioner 7 moves with its lower bearing 14 likewise with the wheel 2 on the line 23 as far as the curved path 17' in the state of spring compression. During the tensioning, the crank 4 pivots about its axis 11 in the direction of the arrow 26 into the position 24 indicated in dash-dot lines in Fig. 4. The curved path 25 shows the possible movement of the lower bearing point 13 of the damper arm 6 during spring-compression and expansion.

Claims

1. A resiliently-mounted guide wheel for a tensionable track df a vehicle, having a rocker member mounted on a vehicle structure, a damper arm supported on the side of the structure and a chain tightener being mounted on the rocker member, wherein the rocker member comprises an angled crank having two guide arms, one guide arm mounted on the side of the structure comprising an eccentric mounting for the damper arm, and the other guide arm facing the guide wheel being arranged eccentrically on the hub of the guide wheel so as to be rotatable therein, a further eccentric mounting for the chain tensioner being provided on the hub.

2. A guide wheel as claimed in Claim 1, wherein the guide wheel is mounted on the crank and guided by the articulation of the track tensioner in such a way that the guide wheel performs an adjustment movement from a basic position to a spring-compression position substantially in the direction of travel between the two runs of the track.

3. A guide wheel as claimed in Claim 1 or 2, wherein in a basic position an axis of the guide arm facing the hub and the mounting of the track tensioner are situated behind a vertical median transverse plane of the guide wheel viewed in the direction of travel, and a mounting on the side of the wall of the other guide arm and the eccentric mounting of the damper arm are situated in front of the vertical median transverse plane viewed in the direction of travel.

4. A guide wheel as claimed in Claim 1, 2 or 3, wherein a line of action of the track tensioner extends under a lever arm towards the axis of the guide arm on the side of the hub.

5. A guide wheel as claimed in Claim 1, wherein in that the mounting of the track tensioner is arranged at a slight distance from the vertical median longitudinal plane of the guide wheel between the guide wheel and the wall.

6. A guide wheel as claimed in any one of the preceding Claims, wherein the mounting of the crank on the side of the wall is arranged in front of the axis of the guide arm on the side of the hub viewed in the direction of travel, and the crank is arranged in the basic position at an angle to a horizontal median transverse plane of the wheel so that in the spring-compression position this angle may be increased.

7. A resiliently-mounted guide wheel for a tensionable track of a vehicle substantially as herein described with reference to the accompanying drawings.