Wheel substitutes for land vehicles – Endless belt having nonmetallic track or tread – Track formed of endless flexible belt
Reexamination Certificate
1998-12-28
2001-01-23
Morano, S. Joseph (Department: 3617)
Wheel substitutes for land vehicles
Endless belt having nonmetallic track or tread
Track formed of endless flexible belt
C305S173000, C305S174000, C305S176000
Reexamination Certificate
active
06176557
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to improvement in an inner periphery driving type rubber crawler having driving protrusions which protrude from an inner face of the crawler.
2. Description of the Related Art
In a conventional structure of a rubber crawler, a plurality of core metals, which are arranged in series along the longitudinal direction of the crawler such that the longer sides of each core metal are in parallel with the width (transverse) direction of the crawler and the center of the core metal is aligned with the center in the transverse direction of the crawler, and a plurality of steel cords surrounding the outer periphery of the core metals, are disposed in a form wherein they are buried in rubber. The central portion of the core metal works as the part which engages with a sprocket (refer to FIG.
17
). Therefore, the core metal has a shape in which the thickness increases toward the central portion and the central portion has the largest thickness. This shape markedly increases the weight of the core metal.
Holes to engage with the sprocket are formed between the core metals in combination with the parts to engage with a sprocket. Because of the presence of these holes, steel cords surrounding the core metals are buried in rubber at positions shifted toward both sides in the transverse direction. Therefore, it is necessary that the rubber crawler and the core metal have large widths.
In other words, a conventional structure of a rubber crawler inevitably gives a large weight to the whole crawler and it is difficult to increase the speed and to decrease the weight. Moreover, the driving force is transferred by the contact of the central portion of the core metal and the sprocket and thus the hitting sound generated by the contact of the metals of both parts becomes a major cause of noise. Holes to engage with the sprocket are arranged in a series at the central portion in the transverse direction of the rubber crawler and this causes another problem in that the arrangement of rubber lugs formed at the outer face of the rubber crawler is restricted. There is the possibility of this restriction in rubber lug arrangement becoming a critical point for decreasing vibration during running.
Particularly when a crawler is driven at a high speed, there is the possibility of the above problems of the conventional rubber crawlers causing problems. In order to solve the above problems, an inner periphery driving type rubber crawler is proposed, in which protrusions are formed at the inner face of a crawler at a constant pitch and the driving force is transferred from a sprocket by the engagement of the pins of the sprocket with these protrusions (refer to FIG.
18
).
The inner periphery driving type rubber crawler has the advantage in that the crawler has a lighter weight than a conventional one because the crawler of this type generally does not have core metals buried therein and that generated vibration is smaller. Thus, the rubber crawler of this type has a structure more suitable for driving at a high speed than the crawler of the type shown in FIG.
17
.
However, the inner periphery driving type rubber crawler has many things to be improved. For example, a driving wheel must have a structure in which the crawler is held down by the wheel at portions in the range of almost the entire width of the crawler because the crawler does not have core metals. Moreover, the driving wheel tends to accumulate dirt because the driving wheel has parts to engage with the driving protrusions.
The conventional inner periphery driving type rubber crawler has the additional problem that the pressure toward the earth in the transverse direction of the crawler cannot be held constant because no core metals are provided and thus a decrease in the pulling power arises and that the probability of wear and chipping of the driving protrusions increases by the contact with the driving wheel made of a metal because the driving protrusions formed at the inner face of the rubber crawler are made of rubber.
SUMMARY OF THE INVENTION
It is an object of the present invention to solve the above problems. The object is achieved by disposing core metals having a specific shape in a conventional inner periphery driving type rubber crawler.
In accordance with the first aspect of the present invention, there is provided an inner periphery driving rubber crawler which comprises a plurality of core metal which are buried in series in the rubber crawler along the longitudinal direction of the crawler such that the longer sides of each core metal are in parallel with the transverse direction of the crawler and the center of the core metal is aligned with the center in the transverse direction of the crawler, and a plurality of steel cords which are buried in the rubber crawler such that they surround the outer peripheries of the core metals.
This rubber crawler especially includes: a pair of horns which protrude from the core metal toward an inner side of the rubber crawler and which have a shape longer in said transverse direction than said longitudinal direction; and rubber members which cover sides of the horn in the longitudinal direction thereof, wherein the horns and the rubber members form a pair of driving protrusions.
In addition, there is provided a driving wheel comprising a sprocket which is inserted between the driving protrusions and driving pins which stand upright to the left and right sides of the sprocket, wherein the driving pins engage with the driving protrusions.
By the above aspect, the structure of the driving wheel is remarkably simplified. Moreover, noise decreases because the driving protrusions made of rubber are brought into contact with the driving pins and wear of the driving protrusions also decreases because the horn extending from the core metal is disposed over the entire area in the transverse direction of the driving protrusions.
In accordance with the second aspect of the present invention, a series of rubber lugs are disposed at an outer peripheral face of the rubber crawler at an oblique angle such that one end of a lug is situated right above one metal core and the other end of the lug is situated right above another metal core adjacent with the one metal core.
By the above aspect, the generation of vibration is more effectively suppressed.
In accordance with the third aspect of the present invention, along a central portion in a transverse direction of an inner face of the rubber crawler which extends in the longitudinal direction thereof, an inner face of the rubber crawler between adjacent core metals is more elevated toward the inside of the rubber crawler than an inner face of a central portion of a core metal between the driving protrusions and the inner face of a central portion of a core metal and the inner face of the rubber crawler are disposed approximately on the same plane.
By the above aspect, rotation of the sprocket can be made smoothly with little movement in the vertical direction.
In accordance with the fourth aspect of the present invention, grooves are formed at both ends in a longitudinal direction of an inner face of a central portion of the core metal.
By the above aspect, a strain formed by the rotation of the sprocket at an inner face of the rubber crawler between adjacent core metals is absorbed by the grooves and separation of adhesion interfaces between the core metals and the surrounding rubber members can effectively be prevented.
In accordance with the fifth aspect of the present invention, each horn has a hole which penetrates the horn in a longitudinal direction.
By the above aspect, when the rubber member is integrally molded with the horn at both longitudinal sides thereof, rubber penetrates into the hole to connect the rubber members at both sides through the holes and thus separation of the rubber members of the driving protrusion from the horn of the core metal is suppressed. Thus, the life of the rubber crawler can be extended.
REFERENCES:
patent: 3118709 (1964-01-01), Case
pate
Bellinger Jason R.
Bridgestone Corporation
Morano S. Joseph
Oliff & Berridg,e PLC
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