Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Chassis for utility vehicle
The present invention pertains to a chassis for a utility
vehicle, especially for agricultural and forestry uses, encompassing a
front frame and a rear frame joined to the former by an articulation
with a vertical swiveling axle, whereas two unconnected raising and
lowering wheel units are provided at the sides of the front and rear
frames and an essentially centered support unit is provided in each
l0 case, while these support units encompass support elements, each of
which has a continuous surface equipped with cleats.
A chassis of this generic type is known from German Patent
(Offenlegungsschrift) No. 2,101,989. In the case of this known
chassis, the support elements of the support units medially positioned
on the front and rear frames are brought into contact with the ground
when the laterally arranged wheel units are raised in relation to the
frame. Therefore, in order for the support elements to be brought into
contact with the ground, the front and rear frames must be lowered.
This results in a relatively slight ground clearance when an especially
high ground clearance would be desirable for traveling over rough
terrain.
Also known and in use are utility vehicles in numerous
designs, which are not equipped with support units on the front and
rear frames. For the most part, these have a front carriage on the front
frame and a rear carriage on the rear frame. In forestry operations,
e.g., they are used within the framework of timber harvesting.
Depending upon whether they are equipped with a timber harvesting
head mounted on an extension arm or with a timber-transport
superstructure they are then called either a "harvester" or a
"forwarder." Harvesters of
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the aforesaid design are, e.g., the "FMG 746/250 OSA SuperEvaTM"
model of the firm Rauma-Repola FMG AB, Alfta, Sweden, and the
"ROTTNE RAPID SNOKENRP" model of the firm Rottne Industrie
AB, Rottne, Sweden; familiar forwarders of the cited design are, e.g.,
the "FMG 250 OSAII model and the "ROTTRE SMV RAPID
RLTCKEZUG" model of the respective firms cited above.
The earth compaction caused by the heavy weight of these
1o utility vehicles represents a significant problem, which must be taken
seriously. It is true that these known utility vehicles are generally
equipped with large-sized, low-pressure tires, so that the surface
pressure exerted by the wheel units on the ground is as low as possible.
Nevertheless, mechanical changes in the soil per se can be determined
after it has been traversed by a utility vehicle with such a known
chassis; and frequently plants growing near the tracks left behind
exhibit symptoms indicative of damage to the roots. Such damage
symptoms can be observed, e.g., on trees growing directly alongside
working lanes traveled by timbering vehicles, the roots of which
2o extend baneath the working lane. The much touted and .applied
measure of covering the working lanes with felled brush in order to
reduce the surface pressure, depending upon the soil conditions and
the thickness of the layer of brush, provides little or no relief; it is,
therefore, time consuming, cost intensive, and detrimental to the
natural resources.
An equipment carrier outfitted with an ordinakry chassis is also
known from German Patent (Offenlegungsschrift) No. 2,434,556.
Each wheel axle of the equipment Garner known from this document
has one or more rocker-like extensions proj ecting in the radial
3o direction. The mutual separation of the wheel axles can be changed by
means of a
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variable-length control element tying the extensions together, so that
the tire equipment can be converted to crawler chains.
From German Patent No. 413,630, a towed vehicle with a
crawler chain centered between the running wheels is known. This
chain is fully integrated in the chassis. When the trailer is to be towed
over rough terrain, the running wheels are removed from the axle and
stored on axle journaled above the axle. As a result, the trailer then
rests on the ground on the crawler chain.
to The fundamental objective of the present invention is the
creation of a chassis of the general type cited in the preamble for a
utility vehicle also employable in rough and/or uneven terrain, in the
utilization of which the natural productivity and durability of the
traversed agricultural or forested land is conserved to the maximum
extent possible. In particular, the roots of plants growing near the
working lanes should not be damaged even by repetitive travel.
This objective is realized in keeping with the invention in
that each support unit encompasses a lift device, by means of which
the associated support element can be both lowered and raised into a
2o position, in which the continuous surface rolls on the ground, while
the two lift devices are so dimensioned that they can together bear at
least half of the total weight of the vehicle.
If a utility vehicle that is equipped with a chassis according
to the invention is driven on soil that is used for agricultural and/or
forestry purposes, the load. corresponding to the weight' of the
vehicle is essentially applied to the ground located centrally
underneath the vehicle; the two
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laterally arranged wheel units of each partial
vehicle in this particular instance only serve as
support devices, i.e., for balancing the vehicle.
The aforementioned measures enable to
substantially reduce the contact forces that may
cause cornpress.ive and transverse strains which
damage the root systems in the stressed soil in
comparison. to a utility vehicle equipped with a
customary chassis within the regions over which the
wheel units travel, and thus within the regions into
which they rooi,-. systems of the plants situated
adjacent i~o the working path penetrate. Here, the
cleats en~;ure that the sensitive topsoil which has a
low resistance i:o penetration need not bear the load
of the vehicle; in normal instances--except during
an extreme drought or if the soil is frozen--the
cleats penetrate the topsoil and apply the load of
the vehic:Le onto the comparatively insensitive and
largely mineral subsoil, which has a high resistance
to penetration (compactness of the soil). Damages
to large-surface contiguous regions, within which
damaging 7_oads are applied onto the topsoil that in
particular is interspersed with capillary roots, are
eliminated with a utility vehicle that is equipped
with the chassis according to the invention. The
point-sha~~ed pE~netration of the topsoil by the
cleats is far less damaging to the roots situated in
this layer than the contiguous surface load that
occurs in the tracks of customary vehicles in which
the entire load of the vehicle is carried by the
wheel units. If a contiguous surface load is
applied onto t:he topsoil, particularly intensive
transverses strains which damage capillary root
systems a.re caused in the soil over which the
vehicle travels, leading to interferences with the
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diffusion of gays and water due to the compacting in
this horizon.
When driving on regular paths and roads, both
bearing components are situated in their respective
raised po;>ition;s. In this particular instance, the
load of the vehicle exclusively rests on the wheel
units, so that the vehicle according to the
invention operates similarly to a utility vehicle
that is equipped with a customary chassis of this
type when trave7_ing on regular roads.
Due t.o the fact that the bearing components may
be raised and :Lowered independently of each other,
just like the wheel units, the position of the
bearing c:ompone~nts may be adapted so that the
vehicle m<~y operate in uneven terrains; this means
that the :lifting devices of the wheel units and the
bearing components may be controlled in such a way
that the vehicle is aligned horizontally. This
measure i;s, foi: example, particularly advantageous
if a crane is attached onto the vehicle, because the
maximum operating range is only available if the
live ring of tree crane is aligned horizontally. A
horizontal. alignment of the vehicle is also
desirable for reasons of safety as well as with
respect to the comfort of the operating personnel.
The horizonta7_ alignment also increases the
stability on working paths situated on a slope with
lateral inclinE~s which may cause a drifting of
customary machines, namely depending on the adhesion
between i:he wheels and the ground, and which
consequently limit the use of such machines. The
sensor-regulated elevation control of the bearing
components; is able to sufficiently lower the center
of gravity of the machine above the ground, since
the latter. faci:Litates an unobstructed rolling over.
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If the crane is operated while the machine is
stationary, the central part may be lowered on the
ground if necessary. In addition, it is possible to
tilt the machinE~ laterally, namely against the force
which act:. within the range of a right angle to the
longitudinal axis as is, for example, the case with
a crane, the boom of which may be extended to a
length of 10 m. The movable bearing components
additionally provide the possibility of retracting
the conta~~t surfaces of the wheels/cleats equally
with respect to the base plate of the central part,
so that the loading of the machine onto a low bed
truck in accordance with the traffic regulations
generally permissible in order to protect the
hydrostatic driving motors which are usually used
for machines of this type and which are not designed
for extended road travel, is eliminated. The motor
and the fluid containers may be stored
advantageously with respect to the center of gravity
in the articulated portion and connected with the
hydraulic devices via short protected connections,
but it is also possible to arrange the
aforementioned devices at different locations
depending on the respective type of construction or
the desired center of gravity.
In cne preferred embodiment of the chassis
according to true invention, each bearing component
comprises a cle~ated roller. This cleated roller is
suspended on the respective partial vehicle such
that its rotation axis extends perpendicularly to
the direcaion of movement of the vehicle; its
cleated outer aurface represents the endless belt
which rolls on the ground. In particular with
larger vehicles,, it may be practical to provide two
or even more rollers or pulleys which are suspended
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parallel t:o eac:h other on the respective frame such
that their rotation axes extend perpendicularly to
the direction of movement of the vehicle on each
bearing component. In this particular instance, the
endless belt which rolls on the ground is formed by
a cleate~i belt which revolves around the two
rollers. This cleated belt may, for example, be
designed as a crawler chain which is provided with
cleats on one side. The cleated belt may be pressed
evenly against the ground by means of a number of
support rollers, as is considered customary with
crawler chain vehicles.
It is advantageous if at least one of the
bearing components is driven by a motor, since
bearer element:. constructed in this fashion are
particularly suitable for driving the vehicle on
trackless terrains. Due to their cleated profile,
the bearer elements are capable of transferring the
high driv~_ng forces required; in addition, the main
portion of the load of the vehicle rests on the
bearing component in a trackless terrain, so that
the danger of ;spinning (slippage) is substantially
lower than in an arrangement in which the drive
actuates the wheel units.
It is particularly practical if both bearing
component; are driven by the driving motor of the
vehicle. This measure facilitates that the hill
climbing ability of the vehicle may be increased
additionally. In this particular instance, the
attachment. of chains onto the wheel units is not
required, even when driving over soft soil. In
instances in which both bearing components are
driven, it is also possible to equip the vehicle
with a ~~ontrol which coordinates both bearing
component; in ;such a way that the cleats of the
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respective: trai:Ling bearing component penetrate into
the depressions which the cleats of the leading
bearing components have impressed into the soil.
This type of coupling of both bearing components
additionally reduces the soil damage, i.e.,
contributes to a superior protection of the soil,
due to the fact that the surface portion of the soil
which is exposed to high loads is minimized.
It is practical that the cleats on the bearing
components be exchangeable. This measure simplifies
the retrofitting of the bearing components with
cleats of a different shape or an exchange of said
cleats due to wear and tear. The vehicle may be
adapted to the local soil conditions (dry, moist,
frozen, thickness of the topsoil) in this fashion
with a relatively low expenditure. Such an
adaptation. is desirable with a view to providing a
maximum protection of the soil. A typical cleat has
a contact surface of 20 x 40 cm; however, different
dimensions. may be practical depending on the
respective: soil conditions. The distribution of the
cleats on the roller and/or the revolving endless
belt (in a row or offset) also depends on the
respective: loca7_ conditions .
A different advantageous embodiment of the
chassis according to the invention suggests that the
height of the c:Leats may be changed, at least within
the region of the respective bearing component with
which the chasscis contacts the soil. One example
for reali~;ing this measure consists in arranging the
cleats on the: revolving endless belt of the
respective bearing component in a moveable fashion,
namely in the radial direction if using a roller as
the bearing component; here, the ends of the cleats
situated opposii~e the soil slide on a guide surface,
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the posit:Lon of which may be altered, a . g . , via two
hydraulic cylinders. Depending on the adjusted
position of the: guide surface, the cleats protrude
from the endless belt of the bearing component to
the corre~;ponding extent.
It i;~ also possible to guide the cleats on the
revolving endless belt of the bearing component in a
longitudinally movable fashion by means of a
correspondingly shaped guide surface on which the
cleats glide wii~h their inner end surfaces such that
they only are extended into the position in which
they proje=ct fi:om the revolving endless belt once
they entirely ~~ontact the soil vertically. This
measure facilitates that a penetration of the cleats
into the t.opsoi7_ may be prevented.
If using cleats that are arranged rigidly on
the revolving endless belt, said cleats preferably
have a front surface that is curved in the shape of
a shell. This measure facilitates that the cleats
are pushed into and/or removed from the topsoil in a
particularly sai'e fashion while entraining a minimal
quantity of soil. It is also possible to provide a
device for moistening the cleats; if the cleats are
moistened previously, they slide in the topsoil in a
superior fashion, and the quantity of soil entrained
when removing the cleats from the topsoil is reduced
substantially.
It is possible to arrange the cleats on the
revolving endless belt in a spring-loaded fashion.
If a bearing component constructed in this fashion
rolls over a large rock or a similar obstacle, the
corresponding cleat situated on the rock is
retracted in a springable fashion. This measure
facilitates thai: all cleats that are in contact with
the soil bear an even share of the load; the
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possibility of overloading individual cleats is
effectively prevented by this measure.
Due t:o the fact that the invention facilitates
that the load of the vehicle is applied onto the
soil in a particularly protective fashion, utility
vehicles E~quipp~ed with a chassis according to the
invention may even be constructed to be heavier than
conventional utility vehicles without dis-
~advantageeus efiEects. Consequently, it is possible
to providE: a utility vehicle of this type with a
timber harvesting device, i.e., a harvester
accessory, as well as a timber transport device,
e.g., grippes or stanchion accessories. This
measure in turn eliminates the necessity of
traveling the same working path twice as it is
currently required due to the separate functions of
the vehicles (harvester vehicles and transport
vehicles). The soil also is protected additionally
due to thE~ fact that the same working path does not
have to be. traveled twice; the repeated travel over
the same soil regions was established as being
particularly damaging to the soil.
One additional development of the chassis
according to tike invention which is discussed in
detail be7~ow in association with the description of
the figures sugcfiests that the main loads are applied
directly onto t:he bearing units. For this purpose,
support a~_ches on which the loads brace themselves
are provided on the swing arms. A utility vehicle
which is designed as a timber harvester and equipped
with a chassis according to the invention is divided
along its longitudinal axis into a front load region
with the driving unit and the crane, a front frame,
a rear frame, and a rear load region with the
transport space. The utility vehicle constructed in
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this fashion has a particularly high stiffness if
additional support arches provided on the swing arms
of the wheel units are connected with the support
arches of the bE~aring units via curved guides, e.g.,
curved guides according to the tongue and groove
principle. A dlirect guidance of the swing arms of
the wheel units which are adj acent to each other as
well as <~ direct mutual guidance of the bearing
units cont:ributE~s to this stiffening of the chassis
due to i:he fact that the lateral forces are
distributed.
It i.s practical that a locking device be
provided which 7Locks the raised bearing units on the
front andlor rear frame while driving on regular
paths. A locking device of this type, e.g., in the
form of a. detent pawl arranged in the frame, may
also serve' for locking additional components, e.g.,
the driving unit:.
Embod.iment:~ of the invention are described in
detail below with the aid of the figures. The
figures show:
Figure 1, an illustration which combines a side
view (righ.t) and a longitudinal section
( left ) of a uti7_ity vehicle chassis
according to the invention,
Figure 2, a bottom view of the chassis
according to Figure 1,
Figure 3, a variation of the chassis according
to Figure 1,
Figure 4, a preferred embodiment of the cleats,
and
Figure 5, a preferred embodiment of a bearing
component.
The chassis illustrated in Figures 1 and 2
comprises a front frame 1 on which a front vehicle
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may be arranged and a rear frame 2 on which a rear
vehicle may be arranged. Both frames are connected
with each other via two collective pivot pins 4 with
a vertica:L pivoting axis 5 so as to form a known
articulated joint 3.
Two front wheel swing arms 6 are coupled to the
front frame 1 such that they may be pivoted around
the horizcmtal <~xis 7: at each of their free ends 8
a front wheel 9 is arranged on an axle 10. Each
front wheel swing arm 6 is braced on the front frame
1 via a double action hydraulic cylinder 11 which is
connected to the swing arm at the coupling point 12
and to the frame at the coupling point 13. Each of
the front wheel swing arms 6 may be raised and
lowered independently in a pivoting fashion around
the axis 7 by means of the hydraulic cylinder 11.
Two rear wheel swing arms 14 are coupled to the
rear framE~ 2 such that they may be pivoted around
the horizontal axis 15. One rear wheel tie bar 17
is arrangEad on each free end 16 of the rear wheel
swing arms 14 ~~uch that they may be pivoted around
the horizontal axis 18. One rear wheel 18a,18b is
arranged on each end of each rear wheel tie bar 17
on an ax:Le 19.. Each rear wheel tie bar 17 is
divided into two sections 17a,17b which are
connected with Each other in an articulated fashion;
here, the: articulated joint 20 has a vertical
pivoting axis which is formed by a bolt 21 that
penetrate; through both sections of the rear wheel
tie bar. When driving around a curve, the rear
sections T~7b of the rear wheel tie bars are pivoted
relative to the front sections 17a in such a way
that the ~~xes of the front wheels 9, the front rear
wheels 18a and 'the rear rear wheels intersect in one
point so as to prevent a grinding of the wheels.
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Each of the rear wheel swing arms 14 is braced on the rear frame 2
via a double action hydraulic cylinder 22 which is connected to the
swing arm at the coupling point 23 and to the frame at the coupling
point 24. Each rear wheel swing arm 14 may be raised and lowered
independently in a pivoting fashion around the axis 15 by means of
the hydraulic cylinder 22.
Two front bearing swing arms 26 which are assigned to the
front bearing unit 25 are coupled to the front frame 1 between the
1 o front swing arms 6 such that they may be pivoted around the same
horizontal axis 7 as the front swing arms. The front support axle 28
which is rigidly connected with the front bearing swing arms 26
extends between the free ends 27 of the aforementioned bearing
swing arms. On the front support axle 28 are arranged two front
support wheel tie bars 29, and between these support wheel tie bars is
arranged a support wheel 30 in a pivoting fashion. One additional
support wheel 30 is arranged at each end of each front support wheel
tie bar 29, and both front support wheel tie bars are connected on one
side by means of one support wheel axle 31 -each, on which the
2o corresponding support wheel 30 rotates. The front, bearing unit thus
comprises a total of five support wheels 30.
An endless link, chain 32 revolves around the support wheels.
The links 33 of said endless link chain have an outer surface 34 that
is curved in a convex fashion and a plane inner surface 35, on which
the support wheels 30 roll. A portion of the links 33 of the endless
link chain 32 carry one cleat 36 each which project from the outer
surface 34. The links thus equipped with cleats are
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distributed over- the chain 32 in such a way that the
chain is ;provided with cleats 36 that are situated
at regular distances from each other.
Each front bearing swing arm 26 is braced on
5 the front frame 1 via a double action hydraulic
cylinder 38 which is connected to the swing arm at
the coupling point 39 and the frame at the coupling
point 40. The two front bearing swing arms 26 may
be raised and lowered collectively, but
10 independently oi= the front wheel swing arms 6, in a
pivoting i=ashion around the axis 7 by means of the
two hydraulic cylinders 38 that are connected
together. The lifting device for the front bearing
unit thus comprises the two front bearing swing arms
15 26 as well as the corresponding hydraulic cylinder
38.
A rear bearing unit 41 is arranged on the rear
frame 2. The design of the aforementioned bearing
unit corresponds with the one front bearing unit 25
20 which is arranged on the front frame 1 and was
discussed previously; reference is made to the
previous explanations so as to eliminate unnecessary
repetitions. T:he type of coupling between the rear
bearing unit 41 and the rear frame 2 also
25 corresponds with the coupling discussed previously
in associ~~tion with the front bearing unit 25; in
this context, rE:ference is also made to the previous
explanations.
The chassis illustrated in Figure 3 in
30 particular difi=ers from the one illustrated in
Figure 1 by the modified design of the components
which serve for bearing the loads. For this
purpose, both upper bearing crossbeams 42 of the
rear framE~ 2 aca as one rear bearing arch 43 each,
35 the central points of curvature of which lie on the
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axis 15 around which the rear wheel swing arms 14
and the rear bearing swing arms 26 may be pivoted.
The rear bearing arches 43 brace themselves on the
lower bearing crossbeams 45 of the rear frame 2 via
one stanchion arch 44 each. The upper bearing
crossbeams 42 and the lower bearing crossbeams 45 of
the rear frame :in addition are mutually stiffened by
means of the two stanchions 46.
The rear bearing swing arms 26 in the
embodiment. illustrated in Figure 3 form an
integrateol component of a transport device 47. For
this purpose, one support arch 48 which extends
upward from each bearing swing arm is provided on
the rear bearing swing arms within the region of
their free ends, namely adjacent the rear bearer
axle. These support arches brace themselves on the
bearing arches 43 of the rear frame in any position
of the rear bearing unit, whereby sliding surfaces
49 are provided on the bearing arches for this
purpose. The axis of curvature of these sliding
surfaces coincides with the pivoting axis 15 of the
rear bear:Lng swing arms. Guides (not shown in the
figures) which prevent a relative lateral offset
between the bearing arches and the support arches
which are assigned to each other are arranged within
the region of the interacting surfaces of the
bearing arches 'which slide on each other as well as
the assigned support arches. In addition, the
transport devices 47 comprises two support stanchions
50 which are directed upward in a slanted fashion
and into which -the rear bearing swing arms merge. A
transport frame which comprises two longitudinal
bearers 57. and 'two transverse bearers 52 is attached
to both support arches 4$ and support stanchions 50;
for this purpose, both longitudinal bearers connect
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one support arch 48 and one support stanchion 50
with each other, while one transverse bearer
connects the two support arches with each other, and
the other transverse bearer connects the two support
stanchions with each other.
This construction results in a rigid transport
device which has a high torsional stiffness and is
coupled directly with the rear bearing unit.
Consequently, the load of the material stored on the
transport device is applied directly onto the soil
via the bearing unit without causing internal forces
in the chassis. This measure enables that the
chassis to be constructed in a lighter fashion
which, in turn, contributes to an additional
protection. of the soil.
In t:he front frame 1, both upper bearing
crossbeams 42 merge into one bearing arch 43 each,
whereby the axes of curvature of these bearing
arches coincide with the pivoting axis of the front
wheel swing arms and the front bearing swing arms,
and the bearing arches brace themselves on the
corresponding lower bearing crossbeams 45 via one
stanchion arch each. Here, as in the case of the
rear frame, the width of the bearing arches is
dimensioned in ouch a way that they cover the wheel
swing arms as well as the bearing swing arms. The
front frame also is stiffened via two stanchions 46
which connect the upper and the lower bearing
crossbeam:.
One upwardly extending support arch 48 is
arranged on each of the front bearing swing arms,
as descrik>ed previously in association with the rear
bearing swing arms. The support arches adjoin the
upper bea~_ing arches of the front frame with their
sliding surfaces 49. The two front support arches
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are connec:ted with each other and are rigidly fixed
at their free ends by means of a connecting
crossbeam 53. Guides, which are not shown in the
figures, are also provided on the support arches and
the bearing arches assigned to the front frame
within the region of the respectively interacting
surfaces, whereby said guides prevent a relative
lateral offset between the arches that are assigned
to each other.
On the two support arches rests a first load
bridge 54 which comprises a transverse bearer 55 and
two guide elements 56 which are arranged at the ends
of said transverse crossbeam and are guided on the
support arches. The load of the components of the
utility vehicle which brace themselves on the first
load bridge i~~ applied directly onto the front
bearing unit via the support arches; as in the case
of the rear frarne, an internal strain of the chassis
does not occur.. If the chassis according to the
invention is utilized on a timber harvester used for
forestry ~~urposE~s, the crane K arranged on the front
vehicle braces itself on the first load bridge,
whereby a universal joint is preferably provided
between the crane and the first load bridge for
equalizing the longitudinal and transverse inclines
which occur during the use of the crane.
Support arches, which are not shown, that are
guided on the x>earing arches 43 of the front frame
are also ~~rovidE~d on the front wheel swing arms 6 of
the chassis illustrated in Figure 3. A second load
bridge 57 comprising a transverse bearer 58 braces
itself on these support arches and two guide
elements 59 which are guided on the outer support
arch are arrangEad on both ends of the aforementioned
transverss~ bearer. If a timber harvester is
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equipped with a chassis according to the invention,
the drive unit T is arranged on this second load
bridge such than its elevation may be adjusted while
it slides on t:he support arches assigned to the
wheel swing arm: .
This adjuatabil.ity of the elevation of the driving
unit simplifies the handling of the timber harvester
and improves the visibility of the working paths in
the forest..
One additional difference of the chassis
illustrated in Figure 3 as compared to the one
illustrated in lFigures 1 and 2 pertains to the rear
wheel tie bar. One guide plate 60 each is provided
on the front of each rear wheel tie bar in order to
stabilize it, in particular while driving in reverse
when the articu=Lated joints 20 of the rear wheel tie
bars 17 (Figure 2) are locked. Each guide plate
engages with onE~ guide groove 62 each with a web 61,
whereby said guide grooves are provided on the lower
bearing crossbeams 45 and the stanchion arches 44 of
the rear frame. This measure enables the rear wheel
tie bars t.o be guided precisely on both sides.
Otherwise, the chassis according to Figure 3
corresponds with the embodiment illustrated in
Figures 1 and 2. In order to avoid unnecessary
repetitions, we refer to the corresponding
explanations of the respective figures.
The hearing component illustrated from a side
view in Figure 4 comprises a cleated roller 63 which
is arranged in a rotatable fashion on the bearing
swing arms 26. The peripheral surface of the
cleated roller is equipped with cleats which have a
planar contact surface 64 and a front surface 65
that is curved in the shape of a shell; the "front
surface" ~_n this context is that particular surface
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of the cleat which first comes into contact with the soil when driving
forward. The cleats are designed as an I-beam 66 onto which the
shell-shaped front surface 65, the plane contact surface 64, as well as
two lateral surfaces are welded. The rear surface of the cleats is open.
Only two of the cleats are illustrated in Figure 4.
The bearing component illustrated in a longitudinal section in
Figure 5 is equipped with cleats, whereby the depth of penetration
into the soil is adjustable. For this purpose, the cleats 36 are guided
to on the endless link chain 32 such that they may be displaced in the
longitudinal direction of the cleats. The cleats are designed to be so
narrow that they may be accommodated between the two support
wheel tie bars 29. The cleats 36 slide with their inner face surfaces 67
on a closed guide rail 68. Each cleat is guided inevitably on the guide
rail by means of clamps 69 which encompass the guide rail on both
sides. Two support wheels 30 are arranged on both ends of each
support wheel tie bar; a central. support wheel is not provided (in
contrast with the hearing component according to Figure 1). The
guide rail may be displaced vertically by means of the two hydraulic
2o cylinders 70 which brace themselves on the support wheel tie bars.
The depth of penetration of the cleats 36 into the soil may be reduced
by upwardly displacing the guide rails 68 and vice versa.
