Multiple Drive for Tracked Running Gear

Abstract

The invention relates to a tracked running gear, in which two running gears are arranged parallel to one another and each running gear has a longitudinal member (1) and a running gear chain (2) which runs around the longitudinal member in the longitudinal direction thereof and forms an upper and a lower strand, and at least one traction drive, composed of a motor, transmission and a drive gearwheel which meshes into the running gear chain and also a deflecting wheel which permits chain tensioning by means of a movement relative to the fixed part of the longitudinal member, characterized in that at least one additional traction drive (3) which acts on the upper strand is provided on the longitudinal member, wherein the running gear length is changed or remains unchanged.

Description

The invention pertains to a crawler, in which at least two crawler assemblies are arranged parallel to each other, and in which each crawler assembly has a longitudinal beam; a caterpillar track, which travels around the longitudinal beam in the longitudinal direction of the beam and which has an upper run and a lower run; at least one drive mechanism consisting of a motor, a gearbox, and a drive sprocket, which meshes with the caterpillar track; and an idler wheel, the position of which can be shifted relative to the stationary part of the longitudinal beam to tighten the track.

In the development of mobile cranes with very large capacities, it is necessary to take into consideration not only the changes in the load-bearing parts of the crane but also those in the parts which provide mobility, namely, the crawlers.

For mobile cranes of this class, which have a high intrinsic weight and which also must be able to move under maximum load, it is essential that suitable and powerful drives be installed in the crawler assemblies, namely, drives which can provide the necessary forward drive forces (drive power). Drives suitable for these larger cranes are available on the market but not in all sizes. It is therefore not possible to purchase an appropriately sized drive to fulfill all of the possible requirements.

The task of the invention is therefore to provide a crawler which can be adapted to different power requirements according to the modular principle.

For a crawler in which at least two crawler assemblies are arranged parallel to each other and each crawler assembly has a longitudinal beam; a track, which travels around the beam in its longitudinal direction and has an upper run and a lower run; at least one drive, consisting of a motor, a gearbox, and a drive sprocket, which meshes with the crawler track; and an idler wheel, the position of which can be shifted relative to the stationary part of the longitudinal beam to tighten the track, the task is accomplished according to the invention by mounting at least one additional drive on the longitudinal beam to act on the upper run, where the length of the crawler assembly remains essentially unchanged.

The additional drive is preferably mounted detachably on the longitudinal beam, and it is advisable in particular for the additional drive to be located at one end of the longitudinal beam.

In the case of mobile cranes which have an undercarriage consisting of wheels and axles, it is possible to change, i.e., to increase, the number of driven wheels or axles.

This can lead to transport problems, however, because, as a result of the increase in the number of driven wheels or axles, the axle load which must be observed for highway transport can be increased beyond the legal limit. In principle, however, adaptation is possible in this way.

The situation is different with tracklaying crawlers. Because of the way in which they are designed, the relationships are different. But even here, for example, the weight will increase when multiple drive units are used, because it is also necessary to increase the number of track links used. The reason for this is that the drive track must be guided over all of the drives, and since these occupy more space, the track must be longer.

According to the invention, additional drives are used which are mounted permanently on the longitudinal beam or mounted on it only when needed. Thus, through careful installation of several drives in series, the drive power can be significantly increased even with standard commercial drives. A very essential aspect is that this multiple drive is installed at one end of the crawler, usually at the end facing away from the travel direction, to take into account the function of track-tightening. By shifting the idler wheel, the track can be brought into a defined state of tension. If the drive were to be divided between the front and back of the crawler, i.e., one at each end of the crawler or at each end of the longitudinal beam, it would be possible to tighten the track only by shifting one of the drive units relative to the other one on the longitudinal beam. This represents a considerable design challenge, because the forces which occur as a result of the extreme operating loads must be transmitted by the complete shifting mechanism into the structure of the crawler. A similar drive arrangement has already been realized in the case of so-called “Terex-Quadro” drive.

To change the tension of the track, an idler wheel, as already described above, is generally used, which can be shifted relative to the stationary part of the longitudinal beam by a shifting mechanism.

With the invention of the single-end multiple drive, it is possible to equip heavy vehicles, especially those on crawlers, such as a mobile crane in the present case, with sufficient installed drive power. Through the arrangement of the multiple drive, preferably at one end of the beam, it is also possible, in a simple manner, to bring about the necessary track tension by means of a shiftable idler wheel, which is located at the end of the crawler opposite the drive. Through the aspect of an adaptable multiple drive, the invention acquires considerable advantages as a result of the availability of additionally introducible drive power. Because this is adaptable, it can be installed additionally on demand or, to achieve an advantageous reduction in the transport weight of the crawler, separated from it and transported separately. Through the possibility of installing a multiple drive at one end of a crawler beam, it is also quite conceivable that this drive power-increasing measure could be installed in such a way that, in addition to the one multiple drive, another multiple drive could also be used, namely, on the shiftable end (i.e., on the track-tightening end). This includes in particular the use of the invention in the previously mentioned Terex-Quadro crawlers, in which, in the standard variant, there are already 4 drives installed on the complete crawler, i.e., two for each track side. Through the use of this multiple drive, we thus obtain a crawler concept in which, in sum, 6 or more drives are installed. Thus it is also conceivable in principle, through the repeated use of the multiple drive on one and the same crawler assembly, to implement the variant of the double-ended multiple drive, in which a multiple drive is installed at each end of the crawler assembly, both in the travel direction in front and in the opposite direction. Through the inventive design, the drive power can thus be increased even more, and in principle any desired power level can be achieved.

In summary, the following advantages are therefore obtained an adaptive solution which allows installation of more drive power, either permanently installed or on demand, on an existing crawler assembly of either modular or nonmodular design. It is possible, through the multiple arrangement of standard commercial gearboxes, to install the necessary driver power without having to resort to large and expensive drive units, to the extent that they are even available on the market in the first place.

Generally, the possibility of guaranteeing adequate drive power for large machines whose intrinsic weight and load must often be moved over unfavorable ground such as that encountered by, for example, lattice-boom crawler cranes.

A wide range of possible uses as a standard or multiple drive, easily realizable through adaptable units.

An expanded range of applications for a crane with modular adaptable crawler units, especially with respect to maneuverability and break-loose behavior on the construction site.

The invention is explained below on the basis of exemplary embodiments:

FIG. 1 shows a diagram of a standard drive such as that already in use for some time. The drive is usually located, as illustrated here, at the end of the crawler facing away from the travel direction.

FIG. 2 shows a diagram of the end of the crawler opposite the drive. As shown here, this end is usually located in the front, facing in the travel direction. The simple solution is shown here, according to which a shiftable idler wheel is used to tighten the track easily.

FIG. 3 shows a schematic diagram of an inventive multiple drive assembly, designed here as a double drive assembly and shown as a permanent installation, which provides the crawler with a greatly increased amount of drive power.

FIG. 4 shows a schematic diagram of another inventive multiple drive assembly, designed here again as a double drive assembly, which is characterized by a flange, which allows an additional drive to be installed adaptably as needed. The schematic diagram shows the adapter of this additional drive, which can be installed with screws, bolts, or similar fastening elements on an existing, appropriately prepared crawler.

FIG. 5 shows a schematic diagram of the use of an inventive multiple drive on a crane with an existing Terex-Quadro drive, which in this variant has 4 drives (2 per track), and which is provided with additional drive power through the installation of the multiple drive.

Claims

1. Crawler in which two crawler assemblies are arranged parallel to each other and in which each crawler assembly has a longitudinal beam;a drive track, which travels around the beam in the longitudinal direction of the beam and which has an upper run and a lower run;at least one drive, consisting of a motor, a gearbox, and a drive sprocket, which meshes with the crawler track; andan idler wheel, the position of which can be shifted relative to the stationary part of the longitudinal beam to tighten the track,

2. Crawler according to claim 1, characterized in that at least one additional drive can be mounted detachably on the longitudinal beam.

3. Crawler according to claim 1, characterized in that at least one additional drive is installed permanently on the longitudinal beam.

4. Crawler according to claim 1, characterized in that the additional drive is mounted at one end of the longitudinal beam.

5. Crawler according to claim 1, characterized in that another additional drive is mounted at the other end of the longitudinal beam.

6. Crawler according to claim 1, characterized in that at least one additional drive is mounted at any desired point along the upper run of the longitudinal beam.

7. Crawler according to claim 1, characterized in that at least one drive unit can be shifted relative to the longitudinal beam by a shifting mechanism.

8. A crawler comprising two parallel crawler assemblies, each crawler assembly comprising: a longitudinal beam having a first end and a second end;a caterpillar track which travels around the first end and the second end of the beam, said caterpillar track having an upper run and a lower run;a drive unit at said first end of said beam, said drive unit comprising a motor, a gearbox, and a drive sprocket which engages the track;an additional drive unit mounted on said beam, said additional drive unit comprising a motor, a gearbox, and a drive sprocket which engages the upper run of said track; andmeans for tensioning the track at the second end of the beam.

9. The crawler of claim 8 wherein the additional drive is readily removable from the beam.

10. The crawler of claim 8 wherein the additional drive is permanently mounted on the beam.

11. The crawler of claim 8 wherein the additional drive unit is mounted at the first end of the beam.

12. The crawler unit of claim 8 wherein the means for tensioning the track is an idler wheel which can be shifted.

13. The crawler unit of claim 8 wherein the means for tensioning the track is a shiftable drive unit comprising a drive sprocket which engages the track.