Crawler undercarriage

Details Crawler undercarriage Crawler undercarriage

1999-07-09

2001-03-20

Stormer, Russell D. (Department: 3617)

Wheel substitutes for land vehicles

With track support intermediate of end wheels

With roller support contacting lower track run

C305S139000, C305S142000

Reexamination Certificate

active

06203124

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates construction machines, and more particularly; to a crawler undercarriage for a construction machine.
2. Description of the Related Art
Such crawler undercarriages generally have two undercarriage halves connected to one another via a frame. One undercarriage half essentially comprises a closed chain with base plates, which runs over a tumbler and idler wheel by means of an interposed supporting frame with a chain tensioning device and, for lower guidance, has track rollers along the supporting frame and, for upper guidance, has carrier rollers.
A carrier roller generally comprises a wheel body portion on the two side faces of which bearing pins are coaxially arranged. The carrier roller is mounted in a rotating manner on the upper part of the supporting frame by means of the bearing pins and corresponding bearings. The carrier roller prevents the chain from rubbing against the supporting frame. The chain rests on the carrier roller and, for guidance, has driving cams, which are shaped in such a way that the wheel body portion of the carrier roller engages in a groove-like portion of the driving cams of the chain. Consequently, an unfavorable movement of the chain transversely with respect to the running direction is avoided. There is frictional engagement between the chain and the carrier roller. Particularly under extreme environmental influences, such as in opencast operation for example, disturbances of the frictional engagement may occur, with the result that it is possible for the carrier roller to come to a standstill. This has the consequence of considerable wear on the carrier roller and on the chain, with the result that the service life of the two components is reduced.
DE 296 16 953 U1 discloses a carrier roller which interacts in a positively engaging manner with a chain in order to avoid the carrier roller coming to a standstill during operation. For this purpose, the carrier roller has cam-like projections on its outer circumference, which engage in recesses present between individual chains links. This type of design does indeed prevent the carrier roller from coming to a standstill on account of the positive engagement; since, however, a relative movement of the two engaged components can take place in the case of the previously known solution on account of the engagement geometry of the carrier roller and chain, here too there is a tendency toward wear. Furthermore, the carrier roller is a quite complex structural design, in particular because of the radially outer cam-like projections, which are fastened on the carrier roller by bolting or by clamping.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a carrier roller of a simple construction in which relative movements between the carrier roller and chain or band are entirely avoided.
This and other objects are in accordance with an embodiment of the invention wherein the carrier roller has a plurality of axially parallel driving pins arranged equidistantly on a coaxial circumferential circle of at least one side face of the wheel body portion. One driving lug of the chain or the band respectively engages between two neighboring driving pins of the carrier roller. In this case, the driving pins may be provided on one or both side faces of the carrier roller.
The engagement with minimal backlash brought about in this way has the effect that relative movements between the chain or band and carrier roller are entirely avoided during forward or reverse travel. The accompanying minimization of wear leads to a considerable increase in the service life of the highly stressed chains or bands, in particular under extreme environmental and material influences. The simple solution ensures a constant rotational movement of the carrier roller and it is possible for conventional carrier rollers to be retrofitted with the solution according to the invention.
According to a further embodiment of the invention, the two surfaces of the driving lugs coming into contact with the driving pins run beveled, i.e. conically with respect to one another. In this way, even if there is continued wearing of the driving lugs, engagement of the chain and carrier roller without backlash is made possible.
The driving pins arranged on one or both sides of the side faces of the wheel body portion may be integrally formed on the wheel body and thereby form an integral cast component. Alternatively, it is also possible to weld or bolt separate carrying pins onto the side faces. The two last-mentioned alternative forms of securement are particularly suitable for retrofitting conventional carrier rollers.
To improve the running properties between the carrier roller and chain, the driving pins may have a round or involute-shaped cross section.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.


REFERENCES:
patent: 2466068 (1949-04-01), Archer
patent: 2827337 (1958-03-01), Buffum
patent: 3472563 (1969-10-01), Irgens
patent: 5899164 (1999-05-01), Coast
patent: 2031824 (1980-04-01), None
patent: 55-94866 (1980-07-01), None
patent: 61-188282 (1986-08-01), None
patent: 62-122868 (1987-06-01), None

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