U.S. patent application number 09/854485 was filed with the patent office on 2001-12-27 for elastic crawler.
Invention is credited to Choi, Yong Jae.
Application Number | 20010054845 09/854485 |
Document ID | / |
Family ID | 18689574 |
Filed Date | 2001-12-27 |
United States Patent
Application |
20010054845 |
Kind Code |
A1 |
Choi, Yong Jae |
December 27, 2001 |
Elastic crawler
Abstract
The present invention provides an elastic crawler having an
improved flexing properties in which arrangement of lugs are
improved so as to prevent deterioration of the flexing properties
due to rigidity of a crawler body increased by providing lugs. The
crawler comprises a crawler body 2, a plurality of core members
3having right and left wings 3R, 3L, respectively, and provided in
the crawler body laterally with respect to the crawler and in
parallel to each other with a space therebetween in the
longitudinal direction of the crawler, and a plurality of right and
left lugs including small lugs provided correspondingly to one of
the wings 3R or 3L and large lugs provided correspondingly to two
of the wings 3R or 3L adjacent to each other in the longitudinal
direction of the crawler.
Inventors: |
Choi, Yong Jae; (Daeduck-ku,
KR) |
Correspondence
Address: |
NIXON PEABODY, LLP
8180 GREENSBORO DRIVE
SUITE 800
MCLEAN
VA
22102
US
|
Family ID: |
18689574 |
Appl. No.: |
09/854485 |
Filed: |
May 15, 2001 |
Current U.S.
Class: |
305/178 |
Current CPC
Class: |
B62D 55/24 20130101 |
Class at
Publication: |
305/178 |
International
Class: |
B62D 055/24 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 23, 2000 |
JP |
2000-190039 |
Claims
What is claimed is:
1. An elastic crawler, comprising a crawler body formed of an
elastic material into an endless band; a plurality of core members
having right and left wings, respectively, and provided in the
crawler body laterally with respect to the crawler body and in
parallel to each other with a space therebetween in the
longitudinal direction of the crawler; and a pair of right and left
lugs raised at positions overlapping projected planes of the right
and left wings, respectively, on a ground-contacting surface of the
crawler body on the right and left sides of a center in a widthwise
direction of the crawler body, wherein one of the pair of right and
left lugs has a ground-contacting surface extending to and
overlapping projected planes of a plurality of right or left wings
on the same side as the lug adjacent each other in a longitudinal
direction of the crawler and having a ground-contacting length in a
circumference direction of the crawler, while the other lug has a
ground-contacting surface overlapping a projected plane of one of
the right and left wings on the same side as the lug and having
another ground-contacting length in the circumference direction,
the ground-contacting length of the latter lug being formed shorter
than that of the former lug so that the ground-contacting surfaces
of the pair of right and left lugs are different in the
ground-contacting length, the pair of right and left lugs having
the ground-contacting surfaces different in the ground-contacting
lengths being alternately arranged in the longitudinal direction of
the crawler so as to be staggered along the crawler.
2. An elastic crawler, comprising a crawler body formed of an
elastic material into an endless band; a plurality of core members
having right and left wings, respectively, and provided in the
crawler body laterally with respect to the crawler body and in
parallel to each other with a space therebetween in the
longitudinal direction of the crawler; and a pair of right and left
lugs raised at positions overlapping projected planes of the right
and left wings, respectively, on a ground-contacting surface of the
crawler body on the right and left sides of a center in a widthwise
direction of the crawler body, wherein one of the pair of right and
left lugs has a ground-contacting surface extending to and
overlapping projected planes of two of right or left wings on the
same side as the lug adjacent each other in a longitudinal
direction of the crawler and having a ground-contacting length in a
circumference direction of the crawler, while the other lug has a
ground-contacting surface overlapping a projected plane of one of
the right and left wings on the same side as the lug and having
another ground-contacting length in the circumference direction,
the ground-contacting length of the latter lug being formed shorter
than that of the former lug so that the ground-contacting surfaces
of the pair of right and left lugs are different in the
ground-contacting length, the pair of right and left lugs having
the ground-contacting surfaces different in the ground-contacting
lengths being alternately arranged in the longitudinal direction of
the crawler so as to be staggered along the crawler.
3. The elastic crawler according to claim 1, wherein an engagement
aperture for engaging a driving wheel is formed at a center in the
widthwise direction of the crawler between the core members
adjacent in the longitudinal direction of the crawler, and one of
the right or left lugs having the longer ground-contacting length
is protrusively formed on the right or left side periphery of the
engagement aperture while the other lug having the shrter
ground-contacting length is protrusively formed on the other side
periphery of the engagement aperture at a forward or rearward
position therefrom in the longitudinal direction of the
crawler.
4. The elastic crawler according to claim 2, wherein an engagement
aperture for engaging a driving wheel is formed at a center in the
widthwise direction of the crawler between the core members
adjacent in the longitudinal direction of the crawler, and one of
the right or left lugs having the longer ground-contacting length
is protrusively formed on the right or left side periphery of the
engagement aperture while the other lug having the shrter
ground-contacting length is protrusively formed on the other side
periphery of the engagementapertureataforwardorr-
earwardpositiontherefrom in the longitudinal direction of the
crawler.
5. The elastic crawler according to claim 1, wherein the
ground-contacting surface of one of the lugs has a
ground-contacting length in the circumferential direction of the
crawler extending to and overlapping the projected planes of two
adjacent core member wings in the longitudinal direction of the
crawler while the ground-contacting surface of the other lug has a
ground-contacting length in the circumferential direction
overlapping the projected plane of each core member wing, and a
pair of the ground-contacting surfaces of the latter lugs adjacent
in the longitudinal direction of the crawler are oppositely shifted
forwardly and rearwardly, respectively, from corresponding core
member wings so that the ground-contacting surfaces of the right
and left lugs are arranged form a continuous ground-contacting
surface in a longitudinal direction of the crawler.
6. The elastic crawler according to claim 2, wherein the
ground-contacting surface of one of the lugs has a
ground-contacting length in the circumferential direction of the
crawler extending to and overlapping the projected planes of two
adjacent core member wings in the longitudinal direction of the
crawler while the ground-contacting surface of the other lug has a
ground-contacting length in the circumferential direction
overlapping the projected plane of each core member wing, and a
pair of the ground-contacting surfaces of the latter lugs adjacent
in the longitudinal direction of the crawler are oppositely shifted
forwardly and rearwardly, respectively, from corresponding core
member wings so that the groundcontacting surfaces of the right and
left lugs are arranged form a continuous ground-contacting surface
in a longitudinal direction of the crawler.
7. The elastic crawler according to claim 1, wherein each of the
core members is formed with right and left protrusions for
preventing come-off of the crawler on the right and left sides of
the center part in the widthwise direction of the crawler on a
no-ground-contacting surface thereof, the right and left
protrusions being arranged to be of fset f rom each other in the
longitudinal direction of the crawler so as to be staggered along
the crawler, and the crawler body is formed on the
no-ground-contacting surface thereof with right and left grooves
for flexion extending in the widthwise direction of the crawler
between core member wings adjacent in the longitudinal direction of
the crawler.
8. The elastic crawler according to claim 2, wherein each of the
core members is formed with right and left protrusions for
preventing come-off of the crawler on the right and left sides of
the center part in the widthwise direction of the crawler on a
no-ground-contacting surface thereof, the right and left
protrusions beingarrangedtobeoffset fromeachother in the
longitudinal direction of the crawler so as to be staggered along
the crawler, and the crawler body is formed on the
no-ground-contacting surface thereof with right and left grooves
for flexion extending in the widthwise direction of the crawler
between core member wings adjacent in the longitudinal direction of
the crawler.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an elastic crawler for
endless crawler vehicles for use in the fields of construction,
engineering, agriculture and the like.
[0003] 2. Description of the Related Art
[0004] An elastic crawler (rubber crawler), in which a plurality of
core metals having right and left wings, respectively, are provided
laterally and in parallel with a space in the longitudinal
direction of the crawler between the core metals in a crawler body
formed of an elastic material into a band shape with no end, and
right and left lugs are provided so as to be raised on positions
overlapping projected planes of the above right and left wings on a
ground-contacting surface side of the above crawler body and
allotted to right and left of the center in the widthwise direction
of the crawler body, is known in the Japanese Examined Patent
Publication No. Hei-79549 and publications of Japanese patents No.
2654926 and No. 2609801, for example.
[0005] The above conventional elastic crawler has a basic structure
in which lugs having a ground-contacting surface having a length in
a circumferential direction covering (extending to) projected
planes of two core metal wings adjacent in the longitudinal
direction of the crawler on a ground-contacting surface side of the
crawler body, are allotted to right and left of the center in the
widthwise direction of the crawler body.
[0006] In the elastic crawler (rubber crawler) disclosed in the
aforementioned publications, the lugs are formed as raised portions
allotted to right and left extend to the wings of the core metals
adjacent in the longitudinal direction of the crawler so that the
rigidity of the crawler body is redoubled, so as to improve
endurance of the lugs, thereby improving endurance of the crawler
itself.
[0007] In the above elastic crawler, however, since all the lugs
allotted to right and left are configured to extend to (cover) the
two core metal wings adjacent in the longitudinal direction of the
crawler, flexing properties at a wrapping section (a section for
wrapping the crawler around a driving wheel, for example) are
deteriorated due to the lugs. This results in an insufficient
engagement with a driving claw, causing a risk of come-off of the
crawler from wheels.
[0008] Furthermore, in the crawler body, since the rigidity at
portions on which lug are formed is large while the rigidity at
portions without lugs between the lugs in a longitudinal direction
of the band of the crawler body is small. Since the rigidity at the
portions with lugs and that at the portions without lugs are
remarkably different, and the large and small rigidity portions are
arranged in turn across a whole length of the crawler, a crack at a
root of the lugs may be caused by a large distortion centered. When
the crack becomes large, water or the like penetrated through the
crack rusts the core metal or a steel code as a tension resistance
body, deteriorating the endurance of the crawler.
[0009] The above problem can be solved to a certain degree by
forming a concave groove corresponding to a portion between the
core metal wings of the lugs (refer to Japanese Patent No.
2654926).
[0010] Forming a concave groove on a ground-contacting surface of
the lugs, however, causes vibration. The vibration transmitted to
and felt by an operator (a driver) may not only cause fatigue, but
also have a bad influence on every kind of mounted equipments,
components and the like.
SUMMARY OF THE INVENTION
[0011] An object of the invention is to improve flexing properties
at a wrapping section by contriving an arrangement of lugs with
respect to core member wings to avoid a cause of a crack at a root
of a lug as well as reduce a cause of vibration, so that endurance
of an elastic crawler is greatly improved as a whole.
[0012] In order to achieve the above-mentioned object, the
following technical ways are taken in the present invention. An
elastic crawler comprises a crawler body formed of an elastic
material into an endless band shape, a plurality of core members
having right and left wings, respectively, provided in the crawler
body laterally relative to the crawler and in parallel to each
other with a space therebetween in the longitudinal direction of
the crawler, and right and left lugs provided so as to be raised at
positions overlapping projected planes of the right and left wings
on a ground-contacting surface of the crawler body on the right and
left sides of the center in the widthwise direction of the
crawler.
[0013] In an elastic crawler according to the invention, one of the
right and left lugs has a ground-contacting surface extending to
and overlapping projected planes of a plurality of wings on the
same side as the lug adjacent each other in a longitudinal
direction of the crawler and having a ground-contacting length in a
circumference direction, while the other lug has a
ground-contacting surface overlapping a projected plane of a wing
on the same side as the lug and having another ground-contacting
length in the circumference direction. The ground-contacting length
of the latter lug is formed shorter than that of the former lug so
that the right and left ground-contacting surfaces are different in
the ground-contacting length, and the right and left lugs having
the ground-contacting surfaces different in the ground-contacting
length are arranged as a pair on the right and left sides of the
center in the widthwise direction of the crawler to be staggered
along the crawler.
[0014] Further, in an elastic crawler according to the invention,
one of the above right and left lugs has a ground-contacting
surface extending to and overlapping projected planes of two wings
of the same side as the lug adjacent each other in the longitudinal
direction of the crawler and having a ground-contacting length in a
circumferential direction, while the other lug has a
ground-contacting surface overlapping a projected plane of a wing
on the same side as the lug and having another ground-contacting
length in the circumference direction. The ground-contacting length
of the latter lug is formed shorter than that of the former lug so
that the right and left ground-contacting surfaces are different in
the ground-contacting length, and the right and left lugs having
the ground-contacting surfaces different in the ground-contacting
length are arranged as a pair on the right and left sides of the
center in the widthwise direction of the crawler to be staggered
along the crawler.
[0015] As a result of adopting above structures in which the right
and left lugs having the ground-contacting surfaces different in
the ground-contacting length are staggered along the crawler and
overlap the projected planes of the wings, the flexing properties
at the wrapping section are improved and come-off of the crawler
can be prevented.
[0016] Here, the projected planes of the right and left wings are
overlapped entirely or a part of the width of the wings (length in
the longitudinal direction of the crawler).
[0017] For circulating a crawler body in the longitudinal direction
thereof, frictional drive by means of a driving drum provided at
the wrapping section may be adopted. Alternately, a claw of a
driving wheel for engaging the crawler body (driving sprocket) may
be provided at the wrapping section.
[0018] In the case of adopting the latter means, it is recommended
to form an engagement aperture for engaging a driving wheel at the
center in the widthwise direction of the crawler body and between
the core members adjacent each other in the longitudinal direction
of the crawler, and to protrusively form one of the lugs on one of
right and left side peripheries of the engagement aperture and
protrusively form the other lug on the other side periphery of the
aperture at a position forward or rearward from the aperture in the
longitudinal direction of the crawler.
[0019] It is also recommended that the ground-contacting length in
the circumferential direction of the ground-contacting surface of
one of the lugs extends to two adjacent core member wings disposed
forwardly and rearwardly in the longitudinal direction of the
crawler while the ground-contacting length in the circumferential
direction of the ground-contacting surface of the other lug
overlaps one core member wing, and the ground-contacting surface of
the above other lug is shifted forwardly or rearwardly from a
corresponding core member wing in order to form a continuous
ground-contacting surface in the longitudinal direction of the
crawler with the ground-contacting surfaces of the right and left
lugs.
[0020] As a result of adopting such structure, vibration during
driving can be restrained, thereby reducing vibration of a machine
body, providing a driver with comfortable driving operation with no
fatigue, and preventing troubles in equipment.
[0021] Furthermore, it is recommended that right and left
protrusions for preventing come-off of the crawler are formed on
the right and left sides in the center part in the widthwise
direction of the crawler on a no-ground-contacting surface of each
core member, the right and left protrusions being arranged to be
offset from each other in the longitudinal direction of the crawler
so as to be staggered along the crawler, and right and left grooves
for flexion laterally extending in the widthwise direction of the
crawler between core member wings adjacent each other in the
longitudinal direction of the crawler, are formed on the
no-ground-contacting surface of the crawler body.
[0022] As a result of adopting such structure, the flexing
properties at the wrapping section are further improved, so that
come-off of the crawler from rolling wheels can be surely prevented
also with the right and left protrusions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a plan view of a ground-contacting surface of a
crawler body in a basic structure of the invention.
[0024] FIG. 2 is a plan view of a no-ground-contacting surface of
the crawler body in the basic structure of the invention.
[0025] FIG. 3 is a sectional view taken along a line A-A shown in
FIG. 2.
[0026] FIG. 4 is a partially cutaway side view of the crawler body
in the basic structure of the invention.
[0027] FIG. 5 is a schematic plan view showing another embodiment
of the invention.
[0028] FIG. 6 is a schematic plan view showing another embodiment
of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] A structure and operation of an elastic crawler 1, a rubber
crawler in this embodiment, according to the invention will be
described hereinafter with reference to the drawings.
[0030] FIGS. 1 to 4 show a basic structure of an elastic crawler 1
having a crawler body 2 formed of an elastic material (elastomer)
such as rubber into an endless band shape, and a plurality of core
iembers 3 having right and left wings 3R and 3L, respectively,
provided laterally relative to the crawler and in parallel to each
other with a space therebetween in the longitudinal direction of
the crawler.
[0031] On a ground-contacting surface of the crawler body 2, right
and left lugs 4R and 4L are provided so as to be raised at
positions overlapping projected planes of the right and left wings
3R and 3L on the right and left sides of the center in the
widthwise direction of the crawler body 2.
[0032] The core member 3 is preferably formed of metal castings or
a sheet metal (pressed), but may be formed of resin such as rigid
resin mixed with reinforcing fiber, for example.
[0033] The core member 3 is also provided with right and left
protrusions 5R and 5L for preventing come-off of the crawler on the
right and left sides in the center part in the widthwise direction
of the crawler on a no-ground-contacting surface thereof. The right
andleftprotrusions5Rand5L arearranged to be offset from each other
in the longitudinal direction of the crawler so as to be staggered
along the crawler, as shown in FIG. 2.
[0034] The core member 3 in the basic structure shown in the
drawings is made of metal castings and the top surfaces of the
right and left protrusions 5R and 5L are formed into a flat plane
since when a center-rib wheel passes on the core member 3, the
right and left portions of the rotary shaft of the wheel roll on
the top surfaces. The right and left protrusions 5R and 5L are
arranged to be offset from each, as shown in FIG. 2, so as to be
substantially continuously provided in the longitudinal direction
of the crawler and exclude a cause of vibration of a center-rib
rolling wheel. The roots of the right and left protrusions 5R and
5L are connected to each other through a connecting portion 3A
which engages a claw of a driving wheel (a sprocket claw), not
shown. The connecting portion 3A has an inner peripheral surface
3A-1 formed into an arcuate shape along a concave portion of the
claw as shown in FIG. 4 so as to be smoothly engaged with and
released from the claw, and an outer peripheral surface
substantially covered with a cover portion 3A-2 made of rubber so
as to prevent rusting.
[0035] The crawler body 2 defines engagement apertures 6 to be
engaged with and released from a claw of a driving wheel at the
center in the widthwise direction of the crawler, which are spaced
to each other so as to be positioned forwardly and reawardly in the
longitudinal direction of the crawler.
[0036] When a straddle wheel passes on the no-ground-contacting
surface of the crawler body 2, the wheels roll on band-shaped guide
surfaces (rail surfaces) 7R and 7L provided on each outer side part
of the right and left protrusions 5R and 5L in the widthwise
direction of the crawler, as shown in FIG. 2.
[0037] Tension resistance members 8R and 8L comprising stacks of
steel wire are embedded in the crawler body 2 on the right and left
sides of the center in the widthwise direction thereof on the
ground-contacting surface side of the right and left wings 3R and
3L of the core member 3, as shown in FIG. 3. The tension resistance
members 8R and 8L are formed to be substantially endless so as to
prevent the crawler body 2 from extending.
[0038] As shown in FIG. 1, one of the right and left lugs 4R and 4L
has a ground-contacting surface 4A extending to and overlapping
projected planes of a plurality of (two, in the case of FIG. 1)
left or right wings on the same side as the lug adjacent to each
other in the longitudinal direction of the crawler and having
ground-contacting length LI in the circumference direction of the
crawler. The other one of the lugs 4R and 4L has a pair of
ground-contacting surfaces 4B adjacent to each other in the
longitudinal direction of the crawler, each of which overlaps a
projected plane of a left or right wing located on the opposite
side of the lug having the surface 4A and has ground-contacting
length L2 in the circumference direction. The ground-contacting
length L2 of the ground-contacting surface 4B in the latter lug 4R
4L is formed shorter than the ground-contacting length Li of the
ground-contacting surface 4A in the formaer lug 4R or 4L, so that
the ground-contacting surfaces 4A and 4B having different
ground-contacting lengths L1 and L2 are arranged on the right and
left sides. The right and left lugs 4R and 4L having the
ground-contacting surfaces 4A and 4B, respectively, in which the
ground-contacting lengths L1 and L2 are different, are disposed on
the right and left sides of the center in the widthwise direction
of the crawler body 2 to be staggered along the crawler.
[0039] For the purpose of easy understanding, in the basic
structure shown in FIG. 1, the lug 4L having the longer
ground-contacting length L1 will be referred to as a large lug 4L,
while the lug 4R having the shorter length L2 will be referred to
as a small lug 4R hereinafter. The large lug 4L is disposed so as
to extend to the projected planes of the two adjacent wings 3L in
the longitudinal direction of the crawler, while a pair of small
lugs 4R are respectively disposed on the projected plane of each
one of the two wings 3R and 3R adjacent in the longitudinal
direction of the crawler. The one large lug 4L and the pair of
small lugs 4R are arranged as a group alternately so as to be
staggered along the crawler.
[0040] As shown in FIG. 1, the one large lug 4L is protrusively
formed on one of the right and left side peripheries 6L of the
engagement aperture 6 while the pair of small lugs 4R are
protrusively formed on the other side periphery 6R at forward and
rearward positions in the longitudinal direction of the crawler, so
that the respective lugs are raised at positions arranged to be
staggered along the crawler. In order to form a continuous
ground-contacting surface in the longitudinal direction of the
crawler with the ground-contacting surfaces 4A and 4B of the above
left and right large and small lugs 4L and 4R, the
ground-contacting surfaces 4B of the pair of small lugs 4R are
shifted (expanded) toward opposite directions so that the front one
is forwardly expanded while the rear one is rearwardly expanded in
the longitudinal direction from the positions of the corresponding
core member wings 3R or 3L. Reference numerals 4B-1 and 4B-2 denote
the expanded portions.
[0041] The above described combination in the arrangement among the
right and left wings 3R and 3L of the core member 3, the engagement
aperture 6, and the left and right large and small lugs 4L and 4R
decreases distortion centered in the roots of the right and left
lugs 4R and 4L to improve rigidity of the crawler body 2, ensures
preferable flexing properties at the wrapping section, and
restrains vibration.
[0042] In the basic structure shown in FIG. 1, the large lug 4L
extends so as to cover around a half of the projected plane of each
of the two wings 3L adjacent in the longitudinal direction of the
crawler, while the pair of small lugs 4R are arranged so that their
phases are shifted forwardly and rearwardly in the longitudinal
direction of the crawler from each of the right wings 3R. Each of
the ground-contacting surfaces 4A and 4B of the large and small
lugs 4L and 4R has an end portion having the largest width (length
in the longitudinal direction of the crawler) at the center of the
crawlerinthewidthwisedirectionthereof, thewidthgradually becomes
smaller toward the side edges of the crawler in the widthwise
direction thereof, so that there is provided earth removing
portions 9R and 9L outwardly flared in the widthwise direction of
the crawler at the spaces between the lugs.
[0043] Moreover, in order to further improve flexing properties of
the crawler at the wrapping section, there is provided right and
left grooves for flexion 10R and 10L extending in the widthwise
direction of the crawler and being almost linearly arranged to each
other between the core member wings adjacent to each other in the
longitudinal direction of the crawler, on the no-ground-contacting
surface of the crawler body 2, as shown in FIG. 2. A bottom of each
of the grooves 10R and 10L is formed into an arc shape as shown in
FIG. 4 so as to prevent concentration of stress.
[0044] In FIGS. 1 and 3, reference numbers 11L and 11R denote
protectors in the right and left outer peripheries of the right and
left tension resistance members (tension resistance bands) 8R and
8L, which are formed into a band shape by raising a portion between
the lugs. The large and small lugs 4L and 4R outwardly extend
beyond the length of the right and left wings 3R and 3L in the
widthwise direction of the crawler.
[0045] FIGS. 5 and 6 show other embodiments of the invention. In
FIGS. 5 and 6, relation in an arrangement of the core member 3, the
large and small lugs 4L and 4R, and the engagement aperture 6 is
shown.
[0046] In the embodiment shown in FIG. 5, the large lug 4L has the
ground-contacting surface 4A extending to the three wings 3L or 3R
while the small lug 4R has the ground-contacting surface 4B
covering the projected plane of each one of the wing 3R or 3L. The
large and small lugs 4L and 4R are arranged as a group alternately
so as to be staggered along the crawler.
[0047] In the embodiment shown in FIG. 6, totally three kinds
(large, middle and small) of lugs, namely, each one of the large
and small lugs 4L and 4R and one middle lug 4X are arranged as a
group alternately so as to be staggered along the crawler.
[0048] That is, the small lug 4R is disposed correspondingly to one
core member wing 3R or 3L and the middle lug 4X is disposed so as
to extend to the other two wings 3R or 3L, when the large lug 4L is
disposed so as to extend to the three core member wings 3L or
3R.
[0049] Though the embodiments exemplified in FIGS. 5 and 6 can
achieve the intended object, the large lug 4L of these embodiments
having greater volumes than the embodiment (basic embodiment) shown
in FIGS. 1 to 4 may have slightly inferior flexing properties at
the wrapping section.
[0050] In order to avoid the above problem, it is preferred to
provide a concave groove extending in the widthwise direction of
the crawler on the ground-contacting surface of the lug, as shown
by a reference number 12 in FIGS. 5 and 6, so as to improve
flexing.
[0051] While the presently preferred embodiments of the present
invention have been described in detail, as will be apparent with
those familiar with the art, various variations and modifications
can be made in embodiments without departing from the scope of the
invention defined by the following claims. For example, it is
possible to modify the design as follows: (1) one or both of the
right and left protrusions 5R and 5L for preventing come-off of the
crawler are formed of rubber; (2) a drum-type drive unit is adopted
driving a crawler; (3) reinforcing fiber is mixed to elastomer for
forming the crawler body or the lug; and (4) a band-shaped belt
plate is adopted as a tension resistance member.
[0052] As described above, the elastic crawler according to the
present invention has improved flexing properties at the wrapping
section which ensures prevention of come-off of the crawler,
reduces vibration, as well as improves durability.
* * * * *