Wheel substitutes for land vehicles – Tracks or treads – With guide means for interfitting with sprocket wheel or roller
Reissue Patent
1998-12-31
2001-07-03
Stormer, Russell D. (Department: 3617)
Wheel substitutes for land vehicles
Tracks or treads
With guide means for interfitting with sprocket wheel or roller
C305S196000, C305S199000
Reissue Patent
active
RE037254
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a chain link for a traction chain, for example an offset model, conveyor chain, for example a straight model, or for similar chain types as well as a guide wheel for guiding and/or deflecting or tensioning conveyor chains, transport chains, or similar chain models as well as a support roller for supporting and guiding traction chains, transport chains, and/or similar types of chains as well as guide rollers to ensure the rolling and force transmission in mechanisms using traction chains, transport chains, and or chain-like systems and functions.
BACKGROUND OF THE INVENTION
Such elements are known in many types in the state of the art. With the known elements the running surface region usually has a linear or nearly linear shape so that nearly horizontal straight-line running surfaces are formed on the engaging surfaces of the parts. This construction is kinematically good mainly with regard to the movements between guide wheel, support roller, and chain link but this known construction is poor with respect to optimal strength and wear in use. With elements made according to the known state of the art the pressures occurring in use result in breaking-out or spalling of the edges in particular of the chain link due to the force distribution.
OBJECTS OF THE INVENTION
Starting from this state of the art it is an object of the invention to provide elements of the described type wherein the pressures created in normal use are mainly directed along force vectors which run radially to the running surface of the chain link or radially to the running surface of the guide wheel or of the support roller or running roller or that are directed inwardly into inner regions of the guide wheel or support roller, not however toward the edges of the running surfaces of the chain link, guide wheel, or running or support roller.
SUMMARY OF THE INVENTION
These objects are attained by a chain link usable a rotatable drive/support element having a support surface. The chain link has a hardened running surface extending in and adapted to ride in a travel direction on the support surface and a side surface also extending in the travel direction and normally out of contact with the element. The running surface has a predetermined width b and is formed of at least one edge region of an outwardly convex arcuate shape seen in the travel direction having a radius R of curvature and a respective corner region extending from the edge region to the side region and of an outwardly convex arcuate shape seen in the travel direction having a radius r of curvature. Herein r/b≅0.05 to 0.11, and preferably R/b≅2.4 to 3.1.
The combination wherein the running surface has adjacent the edge region a noncurved region.
Since the running surface of the chain link is formed so that the forces occurring in use are directed generally radially to the pivot axis of the link or toward the interior of the link, a wear- and above all strength-optimal shape is achieved or the shape forms itself at least after relatively short loading in use.
More particularly according to the invention R/b≅2.4 and r/b≅0.075 to 0.11. In addition the entire running surface is of convex arcuate shape seen in the travel direction. The running surface has two such side surfaces, two such edge regions adjacent the side surfaces, and two such corner regions each joining a respective one of the edge regions to the respective corner region. Furthermore the running surface is formed between the edge regions with a substantially flat center region.
In accordance with other features of the invention the two edge regions join centrally on the running surface so that the entire running surface is arcuate. The support surface has a shape generally complementary to the edge and corner regions of the running surface.
The permissible hardness of the running surface lies between 30 and 60 HRc, preferably between 40 and 50 HRc, and the basic hardness of the chain link is set such that no substantial cross-sectional or surface flow takes place as a result of the pressure created by the running roller, in particular with a permissible stretch-limit relationship or R
e
/R
m
of about 1, preferably with a yield-strength relationship R
e
/R
m
of about 0.65 with particular attention to ensuring a sufficiently plastic working possibility. Here R
e
is the yield strength and R
m
the tensile strength.
It is also preferably provided that the chain link is formed of standard materials, namely hardened steel, preferably with analysis values whereby manganese-sulfide formation is minimized with in particular when manganese steel is used a low sulfur content of less than 0.02%. In this manner material fatigue is avoided.
It is particularly provided that the chain link is formed of alternative materials, in particular with a hard-metal base, fiber-composition materials, ceramic/ceramic compounds and/or technical ceramics, preferably based on Si
3
N
4
(silicon nitrate) with less than 15% by weight of sinter additive, a fracture growth in the subcritical region with a breaking strength KIC smaller than 20 MPam as well as similar materials such that the strength and the ductility are by means of the use and proportions of suitable materials set to an optimal value for the particular use of the chain link, with particular attention to the homogeneity (Weibull modulus m) and m is greater than 10 m.
As a result of the construction according to the invention the use of alternative materials is possible since these materials are as a result of the shape used by the instant invention in a normal-load situation only loaded with pressures that cannot be expected to crack out or destroy the material.
In addition it is preferably provided that the compound convexly arced curve of the side flanks of the running surfaces are formed over the entire length or only in portions of the chain link with their radii R and r preferably such that the parameter combination is R/b1≅2.4 to 3.1 and r/b1≅0.05 to 0.11 or is optimized taking into account various chain-link formations so that depending on the actual application an optimal shape with respect to strength and/or wear is quickly established automatically. The parameter b1 here is determined depending on the chain-link type and the particular link shape, this determination takes into account the shape of the part the running surface rides on (for example the shape of the running surface of the guide wheel or of the running roller) and the surfaces dependent thereon are paid attention to with respect to the forces effective on the side surfaces of the running-surface of the chain link.
The guide wheel, support roller and running roller according to the invention are characterized by modified running-surface shapes which are derived from the special running-surface shape of the piece they run on (e.g. the chain link) and also correspond to a constant nonlinear (arced) function or nonlinear/linear curve combination. A linear or nearly linear curve shape (e.g. a straight line is effective for the optimal technical/physical functioning of the pair of running surfaces—chain link/guide wheel or chain link/support or running roller—taking into account the special running-surface shape of the other piece. e.g. the chain link, for particular technical uses of running systems, conveyors, and chain systems of other constructions and function (e.g. high-speed systems, systems with special shock resistance, and the like) as particular embodiments of the running/surface shape of the guide wheel or of the support or running roller which is arranged at an angle to a normally horizontal running surface is advantageous when the size of the angle is preferably selected that it can also be arranged in accordance with the requirements of the special running-surface shape of the other piece (e.g. chain link) a strength- and wear-optimal shape of the running surfaces and side guide surfaces of the guide wheel or the support or guide roller are established in use as soon as possible all by themselve
Ketting Michael
Pietzsch Christoph
Dubno Herbert
Intertractor Zweigniederlassung der Wirtgen GmbH
Stormer Russell D.
Wilford Andrew
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