GB2088802A - Platform truck - Google Patents

Abstract

A platform truck, particularly for use underground, has a load-carrying platform (1) mounted on bogies (2) through torque-shear springs (4) and bearing pins (5). Each bogie (2) has a bearing bridge (7) adapted to swing about the longitudinal truck axis in a pendulum bearing (6) on the underside of the platform (1), the bearing bridge (7) overlapping a bearing axle (8) having a centrally disposed bearing cup (9) for the spring (4). The ends of the axle (8) each carry a wheel box (10) having two sets of wheel bearings (3) and able to swivel about the transverse truck axis, and each wheel box (10) has a supporting roller (11) for the bearing bridge (7) above the bearing axle (8). The platform truck is thus able to carry extremely heavy loads and negotiate differences in level of joints and points along a track. <IMAGE>

Description

SPECIFICATION A platform truck The invention relates to a platform truck, for underground workings in particular, having a loadcarrying platform and at least two multi-axle bogies having a torque-shear spring disposed intermediate the wheel bearings in each bogie, the load-carrying platform being mounted on the bogies by means of bearing pins keyed into the torque-shear springs.

There are known platform trucks having bogies, in which the wheel pairs have rigid axles. These rigid axles pass straight through the bogies and are devoid of springs. Rigid axles are not entirely advantageous, insofar as that when the track is uneven individual wheels tend to lift off, especially while negotiating points, and give rise to the risk of derailment. Moreover, nonuniform loading must be taken into account. On the other hand, nonuniform loading should be avoided as far as possible, at least when the platform truck is to be used to carry extremely heavy loads. This is usually the case. Accordingly, attempts have been made to enhance the load-carrying capacity of the bogies by providing more robust wheel axles.

However, more robust wheel axles lead on the one hand to an undesirably increased structural height and on the other hand to a significant reduction in ground clearance, so that platform trucks of this type can no longer clear chain transporters or other obstacles frequently encountered in underground workings.

There are also known low-loader trucks for use in underground workings where transport trucks are operated. These low-loaded trucks consist basically of bogies having bogie attachment girders and bearing bridges mounted thereon, in which the bogie attachment girders are swivellably mounted on the bogies by means of interposed bearing pins, the bearing pins are anchored in the bogies, torque-shear springs are keyed on the bearing pins and the bogie attachment girders are keyed on the torque-shear springs. The torque-shear springs in these known low-loader trucks are capable of absorbing tilting, shearing and swivelling displacements and ensuring that in the absence of a load the bogie attachment girders will always return to their prescribed position. These torque-shear springs, in the form of rubber-metal units, function like shock absorbers in every loading direction.However, these known features have not significantly influenced the design of the bogies required in platform trucks for the handling in particular of heavy and extremely heavy loads.

The object of the invention is to provide a platform truck of the type initially described, for underground workings in particular, having bogies adapted to compensate for extreme differences in track level, even on points with a difference in level between the wing rail and the frog, so that the risk of derailment is eliminated.

According to the present invention, a platform truck has a load-carrying platform and at least two multi-axle bogies having a torque-shear spring disposed intermediate the wheel bearings in each bogie, the load-carrying platform being mounted on the bogies by means of bearing pins keyed into the torque-shear springs, the underside of the load-carrying platform in the region of each bogie has a pendulum bearing having a bearing bridge adapted to swing in its mount about the longitudinal truck axis, the bearing bridge overlaps a bearing axle having a centrally disposed bearing cup to carry the torque-shear spring and the bearing pin secured centrally in the bearing bridge, the ends of the bearing axle carrying swivellably mounted wheel boxes containing the wheel bearings and swivelling about the transverse truck axis, and each wheel box has a supporting roller for the bearing bridge, the ends of which rest thereon, axially parallel between its two wheel bearings and above the bearing axle.

The direct effect of these features is that the wheel boxes suspended on the bearing axle at both ends, and therefore the wheels therein, can undergo a pendulum motion about both the longitudinal axis and the transverse axis of the truck. The pendulum motion about the longitudinal truck axis is brought about by means of the bearing bridge, which can swing in its mount about the longitudinal truck axis and is supported both in the torque-shear spring and on the supporting rollers. The pendulum motion about the transverse truck axis is brought about by reason of the swivellable mounting of the wheel boxes on the ends of their bearing axle. Hence the wheels are capable of following any differences in track level and any height changes when passing over points.Moreover, the torque-shear spring mounted centrally in each bogie permits swivelling displacements or angular movements within a prescribed range about the bearing pin in the bearing bridge and thus about the vertical bearing axis of the bogie in question. This swivelling motion is further facilitated by the fact that the bearing bridge and with it the loadcarrying platform are in effect supported on both sides against the supporting rollers mounted in the wheel boxes, which thus roll along the underside of the bearing bridge when a swivelling displacement occurs, so that swivelling can still take place even when the load-carrying platform is carrying a heavy or extremely heavy load.

Consequently, the wheel boxes and the wheels in each bogie are capable of swivelling about all three major axes of an orthogonal Cartesian coordinates system. This explains their ability to negotiate distorted tracks. Furthermore, the central torque-shear spring always ensures that the wheel boxes and hence the wheels in each bogie will return as required to their initial position.

Additional preferred features of significance will now be introduced. To form the pendulum bearings the load-carrying platform has in the region of each bogie pairs of bearing cheeks disposed at right angles to the longitudinal truck axis and having arcuate bearing recesses the bearing bridges are swivellably mounted or guided by corresponding bearing segments in the bearing recesses and the bearing bridges are suspended between the bearing cheeks by means of axially parallel journals running in the direction of the longitudinal truck axis. Pendulum bearings of this type are outstanding for their simple and stable construction and their high load-carrying capacity.

The bearing cup for the torque-shear spring and the bearing pin is set centrally in the bearing axle and attached thereto by welding for example, and it has a floor through which the bearing pin passes and in which the bearing pin is keyed and secured with freedom to move only vertically.

Consequently, the bearing pin can as it were advance deeper into the torque-shear spring and the bearing cup, against the force of the spring, specifically when the load-carrying platform is carrying a heavy or extremely heavy load and the bearing bridge in question is therefore correspondingly loaded. The floor of the bearing cup can have a lower removably secured rnember through which the end of the bearing pin projects and below the lower removably secured member the bearing pin carries a securing washer, which on the one hand prevents the bearing pin from moving up and out and on the other hand prevents loss of the lower removably secured member, which is preferably additionally secured by means of a snap ring or the like.At a prescribed distance on either side from the bearing cup the bearing axle has a bearing flange running in the longitudinal direction of the truck and having arcuate flanks, which engage in corresponding flange recesses on the inner face of the wheel boxes, the bearing flanges being inserted into the flange recesses in the vertical plane and thus at right angles to the bearing axle, and locked in the horizontal plane and thus in the longitudinal direction of the bearing axle. In other words, the wheel boxes can readily be suspended as it were on or in the bearing flanges. It is impossible to draw the suspended wheel boxes out in the longitudinal direction of the bearing axle. Each wheel box can have a removable outer wall for the installation of the wheels, the supporting rollers and the roller bearings.A preferred feature of independent significance is that each of the roller bearings has a bearing body which is pushed and keyed on to the bearing axle in the wheel box and a roller suspension incorporated in a bearing cage for the supporting roller, which cage is mounted on the bearing body with intermediate spring units, for example rubber-metal units. Thus the roller bearings are only assembled into the wheel boxes after first pushing the wheel boxes on to the bearing axle, and are then keyed on to the ends of the bearing axle. This ensures that the bearing bridge always rests on the supporting rollers, even when the wheel boxes and the wheels therein swing about the bearing axle. The supporting rollers remain virtually unaffected by this pendulum motion.

By reason of the pendulum bearings provided between the load-carrying platform and the bogies, the load-carrying platform is free to tilt over until contact is made with the underlying bearing bridges. If this tilting motion must be restricted to avoid load slipping on the platform, the load-carrying platform may be supported on one or both sides, against the bearing bridge or bridges on one or more bogies, by an interposed distance piece, fitted for example directly over the relevant supporting roller. The spring-mounted supporting rollers take care of the corresponding spring mounting of the bearing bridges and thus of the entire load-carrying platform.

The advantages accruing from the invention are to be seen substantially in that it provides a platform truck, in particular for the transport of heavy and extremely heavy loads in underground workings, in which the bogies and wheels have an outstanding capacity for negotiating differences in track level and even height changes at points, so that the risk of derailment is eliminated. In fact, even when the load-carrying platform is carrying a heavy or extremely heavy load the wheels remain capable of swivelling about all three major axes of the orthogonal coordinates system, i.e., about the vertical axis of the bogie, about the longitudinal axis of the truck and about the bearing axis of the wheel box. Hence joints and points can be negotiated with great safety. At the same time, the load-carrying platform is spring-mounted on the bogies.As a result, the platform truck of the invention is outstandingly stable and functionally safe.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side elevation of a platform truck in accordance with the invention with a part in section; Figure 2 is a plan view of the truck of Figure 1 with a part broken away; Figure 3 is a plan view of a bogie of the truck of Figure 1 with parts broken away; Figure 4 is a part-sectional end elevation of the bogie of Figure 2; Figure 5 is a vertical section through a wheel box of the bogie of Figure 2; Figure 6 is a plan view of the wheel box of Figure 5; Figure 7 is a plan view of a bearing bridge in the truck of Figure 1; Figure 8 is a side elevation of the bearing bridge of Figure 7; Figure 9 Is a part-sectional end elevation of the bearing bridge of Figure 7; ; Figure 10 is a plan view of a bearing axle and bearing cup of a bogie of the truck of Figure 1; Figure 11 is a side elevation of the axle and cup assembly of Figure 10; and Figure 12 is a part-sectional end elevation of the axle and cup assembly of Figure 10.

The drawings show a platform truck, for underground workings in particular, having a loadcarrying platform 1 and at least two multi-axle bogies 2 each having a torque-shear spring 4 disposed centrally intermediate the wheel bearings 3, the load-carrying platform 1 being movably mounted on the bogies 2 by means of bearing pins 5 keyed into the torque-shear springs 4. The underside of the load-carrying platform 1 is provided in the region of each bogie 2 with a pendulum bearing 6 having a bearing bridge 7 adapted to swing in its mount about the longitudinal truck axis L. The bearing bridge 7 overlaps a bearing axle 8 having a centrally disposed bearing cup 9 to carry the torque-shear spring 4 and the bearing pin 5 secured centrally in the bearing bridge 7.The ends of the bearing axle 8 carry swivellably mounted wheel boxes 10 each having two sets of wheel bearings 3 and swivelling about the transverse truck axis Q and hence about the bearing axle 8. Each wheel box 10 has a supporting roller 11 for the bearing bridge 7, the ends of which rest and roll thereon, midway between its two wheel bearings 3 and above the bearing axle 8; the rolling motion occurs when the said bearing bridge swivels about the vertical bearing axis V of the torque-shear spring 4 and the bearing pin 5.To complete the pendulum bearings 6 the load-carrying platform 1 has in the region of each bogie 2 pairs of bearing cheeks 1 2 disposed at right angles to the longitudinal truck axis L and having arcuate bearing recesses 1 3 while the bearing bridges 7 are swivellably mounted or guided by corresponding bearing segments 14 in the bearing recesses 1 3 and are suspended between the bearing cheeks 12 by means of axially parallel journals 1 5 running in the direction of the longitudinal truck axis L.The bearing cup 9 for the torque-shear spring 4 and the bearing pin 5 is set and welded centrally in the bearing axle 8 and has a floor 16 through which the bearing pin 5 passes and in which the bearing pin 5 is keyed and secured with freedom to move only vertically, through a stroke S. The floor 1 6 of the bearing cup 9 has a lower removably secured member 18 through which the end of the bearing pin 5 projects and below the member 1 8 the pin 5 carries a securing washer 1 9. At a prescribed distance on either side from the bearing cup 9, the bearing axle 8 has a bearing flange 20, running in the longitudinal direction of the truck and having arcuate flanks 21 which engage in corresponding flange recesses 22 on the inner face of the wheel boxes 10, the bearing flanges 20 being inserted into the flange recesses 22 in the vertical plane and thus at right angles to the bearing axle 8, and locked in the horizontal plane and thus in the longitudinal direction of the bearing axle 8. Each wheel box 10 has a removable outer wall 24 for the installation of the wheels 23, the supporting rollers 11 and the roller bearings. Each of the roller bearings has a bearing body 25 which is pushed and keyed on to the end of the bearing axle 8 in the wheel box 10 and a roller suspension 27 incorporated in a bearing cage 28 for the supporting roller 11, which cage is mounted on the bearing body with intermediate spring units 26, for example rubber-metal units. The spring mounting for the supporting roller or rollers 11 ensures that the bearing bridge 7 and hence the load-carrying platform 1 is spring mounted. The load-carrying platform 1 is optionally supportable on one or both sides against the bearing bridge or bridges 7 on one or more bogies 2 by an interposed distance piece 29, fitted for example over the relevant supporting roller 11, if the tilt of the platform needs restricting.

Claims (9)

1. A platform truck having a load-carrying platform and at least two multi-axle bogies having a torque-shear spring disposed intermediate the wheel bearings in each bogie, the load-carrying platform being mounted on the bogies by means of bearing pins keyed into the torque-shear springs, the underside of the load-carrying platform being provided in the region of each bogie with a pendulum bearing having a bearing bridge adapted to swing in its mount about the longitudinal truck axis, the bearing bridge overlapping a bearing axle having a centrally disposed bearing cup to carry the torque-shear spring and the bearing pin secured in the bearing bridge, the ends of the bearing axle carrying swivellably mounted wheel boxes containing the wheel bearings and swivelling about the transverse truck axis, and each wheel box having a supporting roller for the bearing bridge, the ends of which rest thereon, axially parallel between its two wheel bearings and above the bearing axle.

2. A platform truck as in Claim 1, wherein to complete the pendulum bearing the load-carrying platform has in the region of each bogie pairs of bearing cheeks disposed at right angles to the longitudinal truck axis and having arcuate bearing recesses, the bearing bridges being swivellably mounted by corresponding bearing segments in the bearing recesses and the bearing bridges being suspended between the bearing cheeks by means of journals running in the direction of the longitudinal truck axis.

3. A platform truck as in Claim 1 or Claim 2, wherein the bearing cup for the torque-shear spring and the bearing pin is set in the bearing axle and has a floor through which the bearing pin passes and in which the bearing pin is keyed and secured with freedom to move only vertically through a certain distance.

4. A platform truck as in any one of Claims 1 to 3, wherein the floor of the bearing cup has a lower removably secured member through which the end of the bearing pin projects and below the lower removably secured member carries a security washer.

5. A platform truck as in any one of Claims 1 to 4, wherein at a prescribed distance on either side from the bearing cup the bearing axle has a bearing flange running in the longitudinal direction of the truck and having arcuate flanks, which engage in corresponding flange recesses on the inner faces of the wheel boxes, the bearing flanges being inserted into the flange recesses in the vertical plane and locked in the horizontal plane.

6. A platform truck as in any one of Claims 1 to 5, wherein each wheel box has a removable outer wall for the installation of the wheels, the supporting rollers and the roller bearings.

7. A platform truck as in any one of Claims 1 to 6, wherein each of the roller bearings has a bearing body which is pushed and keyed on to the bearing axle in the wheel box and a roller suspension incorporated in a bearing cage for the supporting roller, which cage is mounted on the bearing body with interposed spring units.

8. A platform truck as in any one of Claims 1 to 7, wherein the load-carrying platform is supported, optionally on one or both sides, against the bearing bridge or bridges on one or more bogies, by an interposed distance piece fitted over the relevant supporting roller.

9. A platform truck substantially as hereinbefore described with reference to the accompanying drawings.