Note: Descriptions are shown in the official language in which they were submitted.
~0s4s28
This invention relates to agricultural and other tractors, such
tractors being of the kind which comprise an engine and front and rear ground
wheels. The term "tractor" is to be interpreted as including vehicles such
as those that are used in civil engineering works and that are intended to be
operable on land not provided with roadways or the like.
According to one aspect of the invention, there is provided a
tractor comprising an engine, two groups of ground wheels, a frame which
comprises at least two portions, said portions being pivotable relative to
one another about a substantially vertical axis, wherein a first portion
supports the engine and a torque converter coupled to the output of the
engine and the second portion supports a console comprising a driving seat,
a steering wheel, steering and operating controls, the first frame portion
being supported by a first group of ground wheels, the second frame portion
being supported by the second group of ground wheels, said console being
turnable through substantially 180 about a substantially vertical axis
relative to said second portion and means provided to retain said console in
a position in which a driver occupying said seat faces generally forwardly
and alternatively in another position in which said driver faces generally
rearwardly of the tractor, coupling means being provided near at least one
end of said frame for coupling at least one attachment to the tractor.
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~54S28
For a better understanding of the invention, and
to show how the same may be carried into effect, ref-
erence will now be made, by way of example, to the ac-
companying drawings, in which:-
FiguIe 1 is a plan view of an agricultural t~actorin accordance with the invention,
Figure 2 is a side elevation of the tractor of
Figure 1,
Figure 3 is a front elevation as seen in the dir-
ection indicated by an arrow III in Figure 2,
Figure 4 is a rear elevation as seen in the dir-
ection indicated by an arrow IV in Figure 2,
Figure 5 is a partial rear elevation, to an en-
larged scale, of the tractor of Figures 1 to 4, the
tractor being illustrated in operation with one ground
wheel in a ploughed furrow,
Figure 6 is a part-sectional plan view, to an
enlarged scale as compared with Figures 1 to 4, of a
rear central region of the tractor of Figures 1 to 5,
Figure 7 is a plan view that is similar to Fig-
ure 1 but illustrates some modifications to the trac-
tor b~ Figures 1 to 6,
Figure 8 is a plan view of an alternative agri-
cultural tractor constructed in accordance with the
invention, and .
Figure 9 is ~ slde elevatlon of the tractor of
Figure 8.
' Referring to Figures 1 to 6 of the drawings,
'i those Figures illustrate an agricultural tractor but
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1~)54528
it is emphasised that this is purely by way of example
and that the invention is equally applicable to a
tractor that is intended for non-agricultural purposes.
~he tractor has a frame that is generally indicated by
the reference 1, said frame 1 comprising a substantial-
ly horizontal beam 2 that is substantially parallel to
the intended direction of forward travel of the trac-
tor that is indicated by an arrow A in ~igures 1 and 2
of the drawlngs. ~he rear end of the ~rame beam 2 with
respect to the direction A is secured to the housing of
a torque converter 3 whose rear, in turn, is secured to
the housing 4 of a differential. ~he output shafts of
the differential carry rear driven ground wheels 5
whose arrangement will be described in greater detail
below. Smaller front ground wheels 6 are indirectly
connected to the frame beam 2 near the leading end
of that frame beam in a manner which will also be
described in greater detall below. ~he tractor has an
engine 7 which, in the example that is being described,
is an internal combustion engine rated at not less than
substantially 100 horsepower~ said engine 7 being mounted
on top of the frame beam 2 at a location in front of the
torque converter ~ so as to lie at a horizontal level
above that of the tops of the front ground wheels 6 with
at least part of the engine as far advanced in the direc-
tion A as are the front ground wheels 6.
A hydraulic mechanism 8 which operates a rear-
mounted three-point lifting device or hitch 9 of the
tractor is arranBed on top of the differential housing
_ 4 -
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10545Z8
4 at substantially the rear of that housing with respect
to the directlon A. The lifting device or hitch 9 com-
prises two upper arms 10 that are located along~ide one
another in horizontally spaced apart relationship, the
arms 10 being turnable upwardly and downwardly about
the aligned axes of corresponding shafts 11. ~he aligned
axes of the two shafts 11 extend substantially horizon-
tally perpendicular to the directlon A and are turnable
by the hydraulic mechanism 8, in a manner that is known .
per se, to raise or lower the upper arms ~0 as may be
required. The free rearmost ends of the upper arms 10
are pivotally connected to the upper ends of correspond-
ing rods 12, the lower ends of those rods being pivot-
ally connected, in turn, to lugs that are located bet-
ween the ends of corresponding lower lifting links 13.
In the embodiment which i5 being described, said lugs
are disposed substantially midway along the lengths of
the two lower lifting li~ks 13. ~he leading ends of
the links 13, with respect to the direction A, are
turnably connected by substan~ially horizontally al-
igned pivot pins 14 to lugs that are carried by the
differential housing 4, the axis that is defined by
the pivot pins 14 being substantially perpendicular
to the direction A.
~ he to~ of a housing o~ the hydraulic mechan-
ism 8 carries a pair o~ substantially symmetrically
identical supports 15 which supports extend obli~uely
upwardly and rearwardly away from said housing to term-
inate at a height above ground level which is substan- - -
- 5 -
-
~545Z8
tially equal in magnitude to ~he diameter of one of the
rear driven ground wheels 5. ~he upper rear ends of the
two supports 15 are rigidly interconnected by a horizon-
tally disposed beam 16 which extends substantially
perpendicular to the direction A throughout nearly
the whole width of the tractor (see Fig~e 1). As
seen in plan view (Figure 1), the beam 16 is located
behind the common axis of rotation of the rear driven
ground wheels 5, said beam 16 supporting a platform
17 that extends forwardly therefrom relative to the
direction A. ~he platform 17 forms part of the bot-
tom of a driving cabin 18. A rear portion of the :
platform 17 is substantially horizontally disposed
but, at a location which is just in front of the
common axis of rotation of the rear ground wheels
5 with respect to the direction A, the platform is
bent over obliquely downwardly and, at its front,
forms a lower cabin floor portion 19 at the foot of
opposite side doors 20 of the cabin. A front wall 21
of the driving cabin 18 has a large central window
(Figure 3) and is located immediately in front of the
leading hi~ged edges of the two side doors 20, those
doors 20 also being provided with windows throughout
most of their respective areas. Access ladders 22
that each comprise fGur rungs are arranged beneath
the two side doors 20 wlth the upper rungs thereof
at substantially the level of the lower cabin floor
portion 19. ~he upper edge of the front wall 21 of
the cabin 18 is connected to a cabin roof 23 and the
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.. . . .
10545Z8
rear edge of said cabin roof is connected to a rearwall 24 of the cabin. ~he side doors 20 of the cabin
18 are located in side w~lls 25 thereof and it will
be noted from the drawings that the rear wall 24 and
side walls 25, like the side doors 20 and the front
wall 21, are provided with windows throughout the
greater parts of their ~espective areas.
A frame 26 is located inside the driving cabin
18 and carries a driving seat 27, a steering wheel 28
and other control members for the operation of the
tractor. lhe platform 17 carries an upright pivot 29
and the frame 26, together with the parts which it
carries, is turnable around the pivot 29 on the plat-
form 17 between the position illustrated in Figure 2
of the drawings in which a person occupying the seat
27 will face forwardly in the direction A and an al-
ternative position, that is turned through 180 about
the axis of the pivot 29, the alternative position
being such that a person occupying the seat 27 will
face rearwardly with respect to the direction A and
towards the window in the rear wall 24 of the cabin
18. Means that is not illustrated in the drawings
is provided to enable the frame 26 to be retained in
either of the two alternative postions about the pivot
29 that have just been described. As seen in plan view,
the whole of the frame 26 i5 located behind the lower
cabin floor portion 19, with respect to the directio~
A, in either of the two alternative positions of use
thereof. ~he driving cabin 18 has a width which is ~ -
_ 7
.
. ..... ... ... . ..
~ - ., .. : . ,:
~)S45Z~
preferably not less than 1.5 metre~ a~d not ~reater
than 1.8 metres and, with such a transverse dimension,
that part of the interior of the cabin 18 that is dis-
posed between the side doors 20 is sufficient to accom-
modate a person standi~g upright where the view of the
~river occupying the seat 27 will not be impeded in
substantially the direction A to any disadvantageous
extent. ~he distance between the lower cabin floor
portion 19 and the cabin ~oof 23 is great enough to
enable anyone who is not unusually tall to stand
without stopping and, if such a person stands side-
ways with respect to the direction A, their inter-
ference with the driver's view in that direction will :~
be at a minimum. ~he driving seat 27 is located wholly
above the level of the tops af the rear driven ground
wheels 5 and the lower cabin floor portion 19 is loca-
ted immediately abo~e the top of the differential hous-
ing 4, bhe latter being spaced from ground level ~y a
distance which is substantially 75% of the diameter of
one of the rear driven ~round wheels 5.
~here is, in fact, a row of four of the rear
driven ground wheels 5 which are individually designa-
:d ted in the drawings by the references 30, 31, 32 and
33. ~he four wheels 30 to 33 are arranged in two pairs
that are disposed at opposite sides of a vertical plane
of substantial symmetry of the tractor which extends in
the direction A~ ~he four rear wheels 30 to 33 all
form part of the original equipment of the tractor~ that ~:
is to say, none of them is furnished as an "optional extra".
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; ' . , 1 ~' ' , ' '
~)S45Z8
The pair of wheels 30 and 31 that is located at one side
of the imaginary plane of substantial symmetry of the
tractor that has been referred to above has the two wheels
rigldly secured to one another and the same is true of the
two wheels 32 and ~3 of the pair located at the opposite
side of the imaginary plane. Due to the provision of the
differential which will be described in greater detail
below, the pair of wheels 30/31 or 32/33 that is at the
outer convex side of a bend negotiated by the tractor
during its travel can rotate at a faster speed than
the other pair disposed at the inner concave side of
that bend. The overall width o$ the row of four wheels
30 to 33 in a horizontal direction that is substantial- ,
ly perpendicular to the direction A is preferably not
greater than 3.0 metres and, in the embodiment which
is being described, said width has a ma~nitude of sub-
stantially 2.5 metreS. ~ach of the wheels 30 to 33
has a pneu,m,atic tyre whose tread width in the same dlr-
ection as that which has just been mentioned is prefer-
ably not less than 35 centimetres and not more than 50
centimetres, a tread width of substantially 45 centi-
metres being adva~tageous. lhe spacing between the
tyres q$ the wheels 30 and 31 of onç pair and between
the tyres of the wheels 32 and 33 of the other pair is
preferably substantially 15 centimetres. ~he distance
between the pneumatic tyres of the two inner wheels
31 and 32 of the two pairs should not be more than 50
centimetres and a magnitude of between 20 cen~imetres
and 40 centimetres inclusive is preferred. In the
:
~.-
~OS45Z8
embodiment which is being described, the distance inquestio~ is substantially 40 centimetres. ~ach of the
four wheels 30 to 33 has an overall diameter which
should not be less than 1 metre and which is advantage-
ously ~etween 1.4 and 1,8 metres. In the embodiment
which is bein~ described, each of the wheels 30 to 33
has an overall diameter of substantially 1.5 metres.
It will be seen from Figure 2 of the drawings that the
driving seat 27 in the cabin 18 is located substantial-
ly vertically above the common axis of rotation of the
four wheels 30 to 33.
As seen in plan view (Figures 1 and 6), the
width of the frame 1 varies significantly lengthwise
therealong~ ~he parts thereof that are located in
front of the rear driven ground wheels 5 (said parts
comprising the beam 2, the torque converter 3, the
engine 7 and cover plates and the like 34 therefor) have
a width that is substantially the same as the distance
between a vertical plane of symmetry of the wheel 31
that extends in the direction A and a similar plane
in respect of the wheel 32, The parts of bhe frame 1
that are located tq the rear of the torque converter
3, with respect to the direction A, are of significant-
ly less width than are the parts disposed in front of
the differential housing 4, the latter ~eing the princi-
pal or only component of the parts now under considera-
tion. ~he width of the rear parts of the frame 1 is
between substantially 30 and substantially 45 centimebres
inclusive and a width of substantially 35 centimetres
- 10 -
10545;Z8
is preferred so that said parts can fit, as illustrated
in the drawings, between the rear wheels 31 and 32 with
sufficient worki~g clearance from those wheels.
Figure 6 of the drawings shows that the cover plates
or the like 34 for the torque converter 3 and the engine
7 are located, together with said torque converter 3 and
engine 7, in front of bhe foremost extremities of the
rear wheels 3~ and 32 with respect to the direction A.
It is noted that the term "torque converter" is used
in a generic sense and is intended to include within
its scope such a mechanism as a manually changeable
gear box. The cover plates or ~ like 34 are closer
to one another than in the part o~ the .frame 1 that
has just been discussed in thç part of the frame that
is di~sed between the rear wheels 31 and 32, the
spacing therebetween beco~ing narrower fro~ a region
of the frame that is located approximately in re~ister
~as seen in plan vieW - ~igure 6) with the foremost ~ -
extremiti~s of the wheels 31 and 32 relative to the
direction At The cover plates or the like 34 supp~rt,
betweqn the wheels 31 and 32, substantial~y harizo~tal-
ly aligned bearings 35 an~ 36 that are spaced aparb
from one another in the direction A. ~he bearings 35
and 36 rotatabl~ support an output or dFivi~g s~aft
37 of the torque converter 3, the shaft 37 carrying,
immediately behi~d the rear bearing 36, a bevei pinio~
3a. ~he teeth of the pinion 38 are in driving mesh
with those of a c~own wheel 3~, the crown wheel 39
being rigid with a rotatable houæing 40 in which sub-
- '11 -
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1~)5452~
stantially hori~on-tally aligned output or half shafts
41 and 42 have their inner ends rotatably journalled,
~he inner ends of the two shafts 41 and 42 carry, in-
side the housing 40, corresponding bevel pinions 43
and 44, the teeth of both those pinions 43 and 44 being
in mesh with the teeth of smaller bevel pinions 45 and
46 that are rotatably mounted in the housing 40, bet-
ween the pinions 43 and 44, so as to be capable of
revolving about a common axis which is rotatably dis-
placeable with the housing but which is always perpen-
dicular to the axis of rotation of the output or half
shafts 41 and 42. It will be realised from the description
that has just been given and from Figure 6, in particular,
of the drawings that the differential is of generally
known construction.
The shaft 47 extends substantially horizon-
tally beneath the output or driving shaft 37 in sub-
btantially parallel relationshi~ with that shaft,
said shaft 47 being rotatably supported by bearings
at appropriate locations in the differential housing
4. ~he shaft 47 projects from the rear of the hous-
ing 4 ~o form a rear power ~ake-off shaft of the trac-
tor at which point it is splined or otherwise keyed to
enable it to transmit-;drive to the working parbs of
various rear-mounted tools and implements. ~he power
take-off shaft 47 is driven from the output side of
the tQrque converter 3 and its speed of rotation rel-
ative to that of the engine 7 is therefore dependent
upon the gear ratio selected at any p~rticular time.
- 12 -
~ 054SZ~
It should be noted that it is possible for the shaft
47 to be driven directly from the engine 7 in which
case its speed of rotation at any particular time will
be the same as that of the output shaft of the engine
7. ~he differential housing 4 is formed with substan-
tially symme~rical lateral projections 48 and 49 whase
centres are substantially coincident with the cammon
longitudinal axis (axis of rotation) of the shafts 41
and 42. Ihe projections 48 and 49 accommodate large
substantially horizontal bearings 50 and 51 for inter-
medi~ regions of the shafts 41 and 42. Projections
48 and 49 have flanges at the inner ends of gently
outwardly tapering axle supports 52 and 53 rigidly
secured to them and it will ~e seen from ~igure 6 of
the drawings that outer end regions of the two axle
supports 52 and 53 receive further substantially hari
zont~l bearings 54 for corresponding regians of the
$h~fts 42 a~d 41. ~he axle supports 52 and 53 are
o~ hollow canstructian and the output or half shafts
41 and 42 which thçy rotatably support, with the ai~
of the bearings 50/51 and 54, have circular discs 55
and 56 rigidly secured to the~ in such a way that the
genqral planes af the discs 55 and 56 are perpendic~
ular to the common longitudinal axis of ratation of
the two shafts 41 and 42. It will be noted that the
rear wheels 31 and 3~ a~e arrnged around the axle
supports 52 and 53 respectively, said wheels 31 and
32 having hub portions 57 and 58 which are dispased
at the sides of those wheels remate from the differ-
:
~054s28
ential housing 4 and which are releasably secured tothe corresponding discs 55 and 56 by bolts 59.
~ he described and illustrated construction
whereby the portions 57 and 58 of the hubs of the
two wheels 31 and 32 project outwardly from the gen-
eral planes of ¢orresponding sides of those wheels
is a substantially conventional one for tractors and,
with commercially available tractor wheels, the per-
pendicular distance between the outermost flat sub-
stantially annular surface of each hub portion 57 or
58 and the general plane of the neighbouring side of
the wheel 31 or 32 concerned is substantially 7.5 centi-
metres. In addition to securing the h~b portions 57
and 58 to the discs 55 and 56, the bolts 59 also secure
identical, but oppositely facing, hub portions 60 and
61 of the rear whçels 30 and 33 respectively to the
twa dlscs 55 and 56, ~s will be evide~t from Figure
6 of the drawings, the substantially flat annular
parts of the hub portions 57 and 58 are sandwiched
by the bolts 59 between the corresponding parts of
the hub portio~S 60 and 61 and the discs 55 and 56
xespectively. ~he axle supports 52 a~d 53 eac~ have
an axial length that is substantially the same as
the width (thickness) of the pneumatic tyre of one
of the wheels 31 or 32. Because of the pro~ecting
construction of the portions 57 and 58 of the hubs
of the wheels 31 and 32, quite large cavities are
formed "inside" those wheels so that the latter, as
briefly mentioned above, effectively surround the
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1(~545Z8
corresponding supports 52 and ~3.
A combined towing and scraping member 62 is
fastened to the bottom of the differential housin~
4 and has a width which is substantially the same as
that of the rear part of the frame 1 which comprises
said housing 4. ~he member 62 is of plate-~ike forma-
tion and has a leading substantially horizontal portion, ~ -
which is rigidly securedto the housing 4, whose length,
in the direc-tion A, is substantially the same as that .
of the radius of one of the rear driven ground wheels
that are collectively indicated by the reference 5,
The member 62 comprises a downwardly and rearwardly in-
clined portion which (see Figure 2) commences at a
location just in fro~t of the axis of rotation of the
wheels 5 with respect to the direction A. ~he rear-
most end of the inclined portion is substantially in
line with rear regions of the wheels 5 as seen in :
side elevation (~igure 2) and is there bent over up-
wardly to form a small subsbantially horizontal por-
tion in which a hole 63 (Figure 6) iæ formed Por tow- . .
ing purposes. ~he small substantially horizontal
portion of the member 62 in which the hole 63 is :
formed is located at a height above ground level
which has a magnitude of between substantially 30%
and sub$tantially 40% of the radius of one of the
rear wheels ~. ~he member 62 has downwardly bent-
over stiffening rims 64 (~igure 5) along the edges
thereof that are generall~ parallel to the direction
A and, since the width of said member 62 is substan-
- 15 ~ -
~S4SZ8
tially the same as that of the housing 4, its two
rims 64 are very close to the inner side surfaces of
the tyres of the two wheels 31 and 32. The rims 64
of the member 62 thus perform the scraping function
of that member because any significant amounts of
mud or the like that may adhere temporarily to the
sides of the tyres in question will be stripped from
those sides as they move past the rims 64. ~he speci-
fied ma~nitude of the distance of the rearmost end of
the member 62 above the ground sur~ace is such that,
should at least one of the tyres of the two wheels 31
and 32 become puncbured or be seriously underinflated,
the bulge that will occur in the lowermost region there-
of will be clear of contact with the member 62.
~ he lower li~ting links 13 of the lifting de-
vice or hitch 9 are disposed above the rearmost end
portion af the member 62 (see particularly ~igure 4)
and said member 62 thus also affords a lower stop
that limits the possible downward movement of the
links 13, ~xtreme rearmost ends o~ the two links 13
are bent over outwardly in opposite directions to form
substa~tialIy pIate-shaped scrapers 65 that are both
disposed substantially hori.ontally perpendicular to
the direction A, the outer extremities of said scrap-
ers 65 bei~ located substantially in vertical median
planes of the tyres of the two wheels 31 a~d 32 thab
extend parallel to the direction A, It preferred, the
extremities ~$ the scrapers 65 may be located even
further apart from on another beyond the median
- 16 -
105~5;28
planes that have just been mentioned. ~he extremities
o~ the scrapers 65 carry end plates 66 that are formed
with apertures (see Figure 2), said end plates 66 being
substantially vertically disposed and substantially par-
allel to the direction ~. ~he leading edges of the
plate-shaped scrapers 65 are very close to the treads
of the tyres of the two wheels 31 and 32 respectively
and, in most positions of the lifting device or hitch
9, said leading edges are at a higher horizonbal level
than are the corresponding rear edges. It will be ap-
preciated that the inclinations of the scrapers 65 to
the horizontal will vary in accordance with the angul-
ar po~tions of the lower lifting links 13 about the
pivot pins 14.
~ he transvqrse supporting beam ~6 carries two
elongated and arcuately curved scrapers 67 that are
both of channel-shaped cross~section. Each saraper
67 extends generally pçrpendicular to the longitudinal
axis of the beam 16 and is located principally in a
corresponding one of the two spaces between the wheels
30/31 and 32/33 respectively. The scrapers 67 are
orientated downwardly from the beam 16 and the centre
of curvature of each arcuately curved scraper is spaced
forwardly therefrom with respect to the direction A.
Each scraper 67 is turnable about the axis o~ a corres-
ponding pivot Pin 68, said pivot pins 68 being substan-
tially horizontally perpendicular to the direction ~
and being mounted near the opposite ends of the beam
16 by support lugs 69. Each pivot pin 68 has a carres-
- 17 -
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: .... .
105452~
ponding coil spring 70 wound around it with said springs
70 arranged in such a way that one end of each of them
is fastened to the beam 16 whilst the opposite end
thereof is secured to the scraper 67 concerned at a
location spaced from the corresponding pin 68. The
springs 70 thus tend to maintain the scrapers 67 in
predetermined angular positions about the axes of the
pins 68 and to return the scrapers 67 to those positions
upon di~placement thereof in either direction about the
pins 68. Each scraper 67 has a width in a horizontal
direction that is perpendicular to the direction A which
is a little smaller than is the distance between the
relatively facing side surfaces of the pneumatic tyres
of the rear wheels 30/31 and ~2/33 respectively. In the
embodiment which is being described, the width of each
scraper 67 is substantially 12 centimetrqs. As an al-
ternative bo the channel-shaped cross-section that is
illustrated ~or the scrapers 67, they may each have a
I-shaped cross-section.
Braçkets 71 (~igure 3) depend from ~he frame
beam 2 at locations near to the leading end of that
frame beam and carry a strong horizontal pivot 72
whose axis is substantially hori~zontally parallel to
the direction A, said axis being ¢ontained in the
aforementi~ned imaginary substantially vertical plane
o, sub$tantialy symmetry of the tractor that extends
in the direction ~. ~he cen~re of a fr~nt axle beam
73 is rockable a~ou~ the pivot 72 between the brackets
71 and the beam 73 is normally substantially ho~izontally -
- 18 - ~
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.. . . . . . . . ............ . - . . . . .
: :
lOS4528
perpendicular to the direction A. ~he axle beam 73 is
freely rockable about the pivot 72 and indirectly carries
the front wheels 6. ~here are two pairs 74/75
and 76/77 of the front wheels 6, said two pairs being
located substantially symmetrically (when they are dis-
posed for straight travel of the tractor) at opposite
sides of the imaginary plane of substantial symmetry
of the tractor that has been referred to above. The
pair 74/75 of front wheels is angularly steerable about
the substantially vertical axis of an intervening shaft
78 and the pair of front wheels 76~77 is steerable in
the same way about the similarly disposed axis of a
shaft 79. ~teering arms 80 and 81 are fastened to the
upper ends of the shafts 78 and 79 respectively and ex-
tend rearwardly and downwardly (see Figure 2) therefrom
in r~arwardly conver~ent (see ~igure 1) relationship. A
track ~od 82 pivotally interconnects the rearmost ends
of the two steering arms 80 and 81 in a generally known
manner and is operatively coupled to the steerin~ wheel
28 by parts which are not illustrated in the drawings
and which it is not necessary to describe for the pur-
poses of the present invention ~he lower ends of the
two shafts 78 and 79 are fastened to short substantial-
ly horizontal housings 83 and 84 respectively, said
housings being angularly steerablq with the shafts 78
and 79 and each of them accommodating a corresponding
one of the hydraulic motors (not illustrated). Each
hydrauiic motor drivqs ones of the corresponding pair
of front wheels 74/75 and 76/77, the hydraulic motors
- 19 - :
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~0545Z~ :
being supplied with oil or other fluid pressure medium
fram a hydraulic pump that is not illustrated ln such
a way that they can rotate at dissimilar speeds when,
for example ? the tractor is negotiating a bend.
Figure 5 of the drawings illustrates the pair
of rear wheels 30/31 at one side of the imaginary sub-
stantially vertical plane of substantial symmetry of
the tractor that extends in the direction A. It will
be seen from Figure 5 that the pneumatic tyres of the
two wheels 30 and 31 have different treads. ~he tyre
of the outer wheel 30 has obli~ue tread teeth 85 and
the tyre of the inner wheel 31 has oblique tread teeth
86 ~ut the radial height of each tooth 86 is between
twice and three times that of each tooth 85. Moreover,
the regular circumferential distance between the teeth
85 of the tread of the tyre 30 is less than the regular
distance between the teeth 86 of the tread of the t~re
31 ? the teeth 86 preferably being spaced apart ~rom one
another by substantially twice the distance between
immedia~ely neighbouring teeth 85.
Figure 7 of the drawings illustrates a tractor
which is basi~ally identical to the one that has already
been described above with reference to Figures 1 to 6 of
the drawings but in which the arran6ement of the rear
driven ground wheels 5 is different. ~he rcw of four ~;
rear wheels 30 to 33 inclusive has an overall width in
a direction perpendicular to the direction A of substan-
tially 2.0 metres which is convenient for travel along
public roads and the like. However, when the tractor
- 20 -
~0545Z~
is to operate in extremely adverse ground conditions,
it is advantageous to employ two additional rear wheels
87 and 88 alon~side the rear wheels 30 and ~ respective-
ly. The overall width of the row which then comprises
six of the wheels 5 is increased to substanti~lly 3.0
metres. Each of the two wheels 87 and 88 has a tyre
width (thickness) of substantially 38 centimetres and
distances of substantially 12 centimetres are left bet-
ween the facing surfaces of the tyres of the wheels 30/
87 and 3~/88 respectively. Once a~ain, in the embodi-
ment of Figure 7, the distance between the tyres of
the two wheels 31 and 32 that are located at immediate-
ly opposite sides of the differential housing 4 is sub-
stantially 24 centimetres. Moreover, output or half shafts
of the differential again project axi~lly through in-
ternal cavities of the wheels 31 and 32 but, in this
case, they also pro~ect through internal ~avities of
the respectively immediately nçighbouring wheels 30 and
33. ~he additional wheels 87 and 88 at the opposite
e~ds of the row are, when fit~ed, secured to the
wheels 30 and 3~ in substantially the same manne~ as
has alread~ been described with reference to Figure 6
of the drawings for the connections between the wheels
30/31 and 33/32. However, i~ will be ~oted ~hat, to
this end, the wheels ~0 and 33 require to be furnished
with hub portions that ~re similar to the Portions 57/
58 and 60~61, at both their opposite sides or to be
provided with sçp~rate auxiliary hub portions. ~igure
7 illustirates the provision of single front ground
- 21 -
1054528
wheels 6 at opposite sides of the frame 1 but it is,
of course, possible to provide the wheels 6 in pairs
as has already been described with reference to ~`igures
.~
1 to.~ of the drawings.
In the embodiment of Figure 7, the towing and
scraping member 62 is of a different construction to
that which has been described above. A rearmost end ..
portion of the member 62 has a scraper 89 rigidly sec-
ured to it so as to extend substantially horizontally
perpendicular to the direction A. It will be noted
from Flgure 7 that the opposite free ends of the scrap-
er 89 are located beyond substantially vertical median
planes of the tyres of the twa wheels ~1 and 32 that
extend parallel to the direction A. The member 62
itself once again has the previously described rims 64
that co-operate scrapingly with the $acing inner sidç
surfaces of the tyres of the two wheels 31 and 32. The
extremities of the scraper 89 carry end plates 90 that
both extend substantially vertically parallel to the
direction A, ~he end plates 90 project rearwardly
from the scraper 89 with respect to the direction A
and are provided with substa~tially horizontally
aligned rotatable eyes 91 which surround holes to
accommodate ~hafts, bolts or the like that enable
çonnections to be made to various implements and .
tools. A lug 92 projects rearwardly from the scraper
89 at a location centrally across the width of the
tractor and is $ormed with a hole 93 for towing pur-
poses, said apertured lug 92 constituting a towing member or ~
- 22 - -
'.
1054528
hook. When, as illustrated in Figure 7, only single
front ground wheels 6 are provided, those ground
wheels are undriven and serve only supporting and
steering functions.
~ igures 8 and 9 o~ the drawings illustrate
a tractor having a frame which comprises two rela-
tively pivotable portions 94 and 95. The front por-
tion 94 with respect to the direction A is turnable
relative to the rear portion 95 about the substantially
vertical axis of a strong bipartite pivot 96. ~he
front frame portion 94 comprises a hollow beam 98,
the rearmost end of that beam 9~ with respect to the
direction A being furnished with a fork 97 the limbs
of which support the two parts of the strong pivot 96.
~he leading end of the beam 98 ~ith respect to the
direction A supports an internal combustion engine
99 of the tractor. $he be~m 98 is provided, at loca-
tions between the pivot 9~ and the engine 99, with
substantially symmetrically arranged lateral projec-
tions 100 and 101, said projections 100 and 101 bei~g
similar in construction and function to the previous-
ly described projections 48 and 49. Once again, a
differçntial is located inside the hollow beam 98 and
partially within its projections 100 and 10~, said dif- -
ferential being driven from a shaft which extends from
the tor~uç canverter to the di$ferential. ~he torque
converter is coupled ~o the oubput of the engine 99 and
is not shown in the drawin~s. Output or half shafts
extend coaxially in opposite direçtiors from the pro-
_ 23 -
'' ' ' , '
1~)5452~
jections 100 and 10~ and have hub portions of front
ground wheels 102 and 103 releasably secured to discs
at their outer ends. ~wo further front ground wheels
104 and 105 are arranged beyond the ground wheels 102
and 103 respectively, the connections between the hub
portions of the wheels 102/104 and 103/105 being the
same as has already been described with particular
reference to ~igure 6 of the drawings. Thus, the
proaections 100 and 101 extend into the internal cav-
ities of the wheels 102 and 103 respectively together
with the half shafts or output shafts of the differ-
ential. As seen in side elevation (~igure 9), the
stron~ pivot 96 is lo¢ated very close to the rearmost
extremities of the row of wheels 102 to 105, with res-
pect ta the direction A, the engine 99 being located
wholly in front of said row of wheels relative to the
same direction.
~ wo tanks 106 and 107 which are arranged to
contain liquia fuel for the engine 99 are,disposed in
sy,m~etrical relationship at the front of the tracbor,
said tanks being secured to opposite substantiall~
vertical side walls of a housing of the engine 99.
~he fuel tanks 106 and 107 are thus also located
wholly in front of the row of wheels 102 and 105 with
respect to the direction A~ ~he two tanks 106 and 107
projeo~ from opposite sides of the housing of the en-
~ine 99 and, as seen in plan view (~igure 8), each of
them is of substantially right-angled triangular con-
figuration. As seen in ~igure 8, the "opposite" sides
'' ' .~
- 24 - ,
,, . .:
;
~ ,..... .
: , - -- - , ; -. . - . .. ,, .- . ~ , - . .
16~545Z~
of the triangles coincide with the substantially ver-
tical side walls of the engine housing, the "adjacent"
sides of the triangles projecting perpendicularly from
said side walls at the rear of the "opposite" sides
and the two "hypotenuses" are in forwardly convergent
relationship with respect to the direction A and sub-
stantially intersect the "opposite" sides at the fronts
of the triangles.
~ he leadin~ end of the rear frame portion 95
is engaged around the strong pivot 96 between the
upper and lower limbs of the fork 97. ~he rear frame
portion 95 has substantially the same width as does
the beam 98 that forms part of the front frame portion
94, said width pre$erably being between substantially
20 centimetres and substantially 40 cenbimetres, ln-
clusi~e. The e~ine housing that is supported by the
beam 98 has, as ca~ be seen in ~i~ure 8 of the drawings,
a considexably ~reater wid~h and parts that are carried
by the rear frame portion 95 are also of greater width.
The frame por~ion 95~ which is of hollow formation, is
provided wi~h substantially symmetrically disposed oppo- -
site lateral projections 108 a~d 109 clo9e to its rear
end with respe¢t to the direçtion A. The proaections
108 and 10~ form part of a differential hosuslng and are
similar in construction to the projections 48/49 and 100/
101 that have been referred to aboveO The projections 108
and 109 extend into internal cavities of two rear ground
wheels 110 and 111 together with the axle housingq of half
shafts or output shafts of the last-mentioned differential.
25 -
.
.
lOS~528
~wo further rear ground wheels 112 and 11~ are mount-
ed alongside the ground wheels 110 and 111 respective-
ly to form a row of four rear ground wheels, the con-
nections between hub portions of the wheels 110 and
112 and the wheels 111 and 113 being effected in the
same manner as has already been described above with
particular reference to ~igure 6 of the drawings. ~he
hollow frame beam that principally affords the rear
frame portion 95, together with its projections 108
and 109, is substantially the equivalent of the dif-
ferential housing 4 and lts projections 48 and 49.
Similarly, the rear ground wheels 110 and 111 corres-
pond to the rear ground wheels 31 and 32 of the first ~ :
embodiment. It iwll, however, be noted that,. in the
embodiment of Figures 8 and 9 of the drawings, part
of the rear frame portion 95 is disposed between the
first row of fronb wheels 102 to 105 inclusive and
the rearwardly spaced second row of rear wheels 110
to 113 inclusive.
~ he sizes of the pneumatic tyres of ~he wheels102 bo 105 and 110 and 113 a~d the distances between
them may conveniently be the same as has already been
described with reference to the rear ground wheels 5
of the embodiment o~ ~igures 1 to 6 of the drawings
or to the embodiment of ~igure 7 thereof. ~he same is, ~.
of course, true o$ the wheels themselves. Similarly,
the different tread pabterns of the tyres of the inner
wheels 31 and 32 as compared with those o~ the tyres
of the outer wheels 30 and 33 may advantageously be
- 26 -
,, .. ~ ~, . ., ;. . ~ .
. : , . ,:. . ., , . ~ ~: -
.. .. . . . . , . . : ,
11~545Z8
employed for the inner wheels 102, 103, 110 and 111 as
compared with the outer wheels 104, 105, 112 and 113.
~igures 8 and 9 illustrate -the provision of a rear
lifting device or hitch that incorporates the previous-
ly described member 62, the scraper 89 and the aper-
tured end plates 90. However, if preferred, the rear
lifting device or hitch of the embodiment of Figures 8
and 9 of the drawings may also incorporate a rear tow-
ing hook in the form of the apertured lug 92 that is
illustrated in Figure 7.
As mentioned above, the output shaft of the
engine 99 drives a tor~ue converter that is not illus-
trated and, in turn, the torque converter is arranged
to rotate an output or driving shaft 114 that extends
substantially horizontally rearwardly therefrom. ~he
re~rmost end ~f the driving shaft 114 is provided with
a universal joint 115 whose centre is coincident with
the axis that is defined by the separate coaxial upper
and lower portions of the strong pivot 96. The univers-
al joinb 115 is connected to the front of a further driv-
ing shaft 116 that extends rearwardly therefrom into
the differential housing from which the rear wheels
110 to 113 inclusive are driven. ~hus, all eight of
the ground wheels 102 to 105 and 110 to 113 can be
driven simultaneously.
~ driving ~eat 117 is mounted on a frame 118
thab also support~ a steerin~ wheel 119 and other con-
trols (not il]us~rated? for the operation of the trac,
tor. ~he ~rame 118 and the parts which it carries are
- 27 -
,~ .
,, .
~35452~
turnable through substantially 180 about a~ upright
pivot 119 ~ between the position illustrated in Figure
9 of the drawings in which a driver occupying the seat
117 faces forwardly with respect to the direction A and
a po~tion i~ which he will face rearwardly with respect
to that direction. Means (not illustrated) is provided
to retain the frame 118 in either of the two positions
that have ~ust been mentioned. In the position of the
frame 118 that is illustrated in ~igure 9 of the draw-
ings~ the driving seat 117 is located substantially
exactly vertically above the common axis of rotation
of the rear ground wheels 110 to 113 inclusive where- -
as, when the other possible operative position of the
seat 117 is employed, said seat will be located above
front regions of the ~heels 110 to 113 inclusive as
seen in side elevation and with respect to the direction
A. ~he seat 117, the steering wheel 119 and the other
controls (not shown) are enclosed in a driving cabin 120
that has a front door (not shown). Access to the front
door is b~ way of a flight of steps 121 which comprises
rungs 122 and 123 that are located in a symmetrical ~an-
ner at opposite sides of the rear frame portion 95 -
and further rungs 1~ that are located substantially
ce~trally above the frame portion 95 to terminate near
the foct of t~e front door of the cabin 120. ~ach of
the rear driven ground wheels in each of the embodi-
ments that has been desçribed has an overall diameter
which should not be less than substantially 100 centi-
metres and which is advantageously between substantial- ~ -
.
1054528
ly 140 and 180 centimetres. A diameter of substantial-
ly 150 centimetres is employed in the examples which
have been specifically described.
High powered tractors that can exert a strong
driving torque on their driven ground wheels are often
incapable of transforming that driving torque wholly
into tractive effort since, for example, heavy and/or
prolonged rainfall can soften the ground to such an
extent that the driven wheels skid or sink into the
soil surface. So-called cage wheels have been pro- -~
vided alongside driven pneumatically tyred ground
wheels that are suitable for use on public roads and
that form part of the original equipment of the trac-
tor in an effort to extend the area of contact between
the wheels and the ground surfaçe during operation on
sq~t land but, although they improve the proportion of
the drivingtorque that c~n be converted into ~ractive
effort, their provision substanti~lly increases the
overall width of the tractor to such an extent that it
cannot be driven along public roads in most countries
without breaking the laws of those countries. Although
it is, of course, possible temporarily to remove the
cage wheels for public road transport purposes, this
is tiresome and inconvenient when frequent journeys
along public roads have to be made. Many known trac-
tors have the disadvantage that their origina~ s-tand-
ard widths are equal or very nearly equal to the leg-
ally prescribed maximum road transport widths of the
countXies of origin so that the addition of driven
- 29 -
.. . . .~ ~ .
16~545Z8
cage wheels or the like with a view to increasing
the area o~ contact with soft soil when the tractor
is in use makes it illegal to drive th~ tractor along
public roads. Without the added driven cage wheels
or the like, the area of contact between the original
wheels and so~t soil is insufficient so that the trac-
tor cannot produce enough tractive effort to move many
heavy implements and tools without skidding, wheel spin
or serious sinkage into the unstable ground surface.
~ractorsin accordance with the invention may have a
large area of contact between their tyres and the soil
surface so that they can produce a high tractive ef-
fort befqre significant wheel slip or sinkage will
occur and this important advantage is realised with-
out having an overall tractor width that infringes
public road transport regulations. ~he overall width
of that part of the tractor frame to which the driven
wheels are connected is drastically reduced as compared
with conventio~al tractors so that there is sufficient
space for a row of driven ground wheels whpse tyres, in
total, have a lar~e area of contact with soft ground
and consequently exert a low pressure u~on the ground
surface per unit area o$ tyre in contact therewith. ~hus~
under all but the most extreme of adverse conditions,
substantially all of the engine torque that is applied
to the driving of the ground wheels can be utilised as
tractivç effart. ~he maximum permitted width of the
tractor (for road transport purposes) is thus utilised
in an optimum manner and a tractor in accordance with
- ~0 -
10545Z8
the invention can be used satisfactorily in soil con-
ditions which wou~ render the employment of a conven-
tional tractor either very difficult and uneconomic or
substantially impossible.
~ he engine 7 of the tractor that has been des-
cribed with reference to ~igures ~ to 6 of the drawings
drives the sha~t 37 by way of the torque converter 3, -
which may beamanual gear box, and said shaft 37 is
enclosed in the housing 4 which is no greater in width
(thickness) than one of the tyres of one of the driven
rear wheels 5. Such width should not be more than sub-
stantially 50 centimetres and it is preferred that it
should be within the range of substantially 20 centi-
metres to substantially 49 centimetres~ ~his small
width is possible because the distance between the
substantially vertical side cover plates or the like
34 of the housing 4 is determined principally by the
dimensions of the bearings 35 and 36 of the shaft 37.
Although the portion of the housing 4 which actually
contains the differ-ential is greater in width than is
the remainder of that housing, this does not destroy
the advantages of the invention because the projections
4~ and 49 that partially contain the differential are
ente~ed into the hollow interiors of the inner ground
wheels 31 and 32, such ground wheels being commercial.
ly available tractor ground wheels that, accordingly,
do not have to be purpose-built for employment with
tractorsin accordance with the invenbion~ ~he hub
portions 57 and 58 have flat parts that are located
- 31 -
,, ~ . . .. . . .
105'~528
laterally beyond the general planes of corresponding
sides of the tyres of the wheels concerned and this
enables the hub portions of two different wheels to be
quickly and easily fastened to one another in abutting
relationship. The distance between the flat part of
each such hub portion and the general plane of the
neighbouring side of the tyre of the wheel concerned
is the principal ~actor in determining the distance
between the tyres of two immediately neighbouring
wheçls of one of the rows of such wheels that have
been described. However, it is not essential that
the hub portions should have the shapes that have been
described in regard to the portions 57/58 and 60/61.
As an alternative, tractor wheels ~ay be used which
have hub portions comp~ising flab parts that are sub-
stantially coincident with, or located internally be-
hind, the general planes of the sides of tyres when
~itted to the corres~onding wheels. When such whèels
are employed, the tyres that are fitted thereon abut
a6ainst one another in side-by-side relationship with
substanbially no space ab all between them except where
the housing 4 is situated. Apart from that necessary
sp~ce, substantially the whole of the prescribed width
(for public road transport purposes) of the tractor can
be occupied by pneumatic tyres and no significant amounts
of mud w~ll be able to penetrate between the abutting
tyres without the provision of scrapers.
It can 4e seen in Figure 6 of the drawings that
it would be possible to increase the width of the dif-
~.
_ ~2 ~ ~
. .
10545Z8
ferential by ~h~rtenin~ the axle supports 52 and 53,the width o~ said differential being effectively the
distance between the outermost extremities of the
lateral proiections 48 and 49 of the housing 4. Such
an arrangement can be made, when required, and is ad-
vantageous inasmuch as it enables larger and stronger
moving parts to be employed without adding to the
overall width of the rear of the tractor provided
thatthe enlarged projections still fit with adequate
clearance in the internal cavities of the wheels 31 and
32. ~he available space is thus used in an optimum
manner. In the embodiment of Figures 1 to 6 of the
drawings, the tractor has four of the rear driven ~-
ground wheels 5 that give an overall width of substan-
tially 2.5 metres and, in addition, has four of the
smaller front wheels 6 which latter engage the ground ~
surface with a fairly high pressure because the engine
7 is disposed above and between them. ~he significant
pressure with which the ~ront wheels 6 engage the
ground surface may, as briefly mentioned above, advantT
ageously be utilised in converting the driving torque
of the engine 7 into tractive effort by arranging
hydrauliç motars for the front wheels 6 in the housings
83 and 84.
In the embodiment illustrated in Figure 7 of
the drawi~gs, the transport width (without the wheels .
87 and 88) is substantially 2.0 metres and the addition
of the wheels 87 and 88 increas~ that width to substan- ~ -
tially 3 metres, the latter being legally allowable on
- 33 -
,. , . ., . . : - ~ ~
1~545Z8
public roads in many countries and being possible under
special licence in others~ When the wheels 87 and 88
are m~unted in their operati~e positions as shown in
~igure 7 of the drawings, the tractor has six driven
rear wheels.
~ he tractor that is illustrated in Figures 8
and 9 of the drawings has eight driven ground wheels
which are arranged in a front row and a rear row with
each row comprising four of the wheels, the overall
width o~ the tractor being within the legally allowed
limits for travel on public roads. However, if desired,
each of the two rows of four ground wheels may have
two further ground wheels added to its opposite ends to
give a total of twelve ground wheels arranged in two
rows of six wheels each in the same manner as has al- :
ready been described with reference to the rear ground
wheels of the embodiment of Fi~ure 7. Onoe again, it
is possible to dispose a larger than usual number of
driven ground wheels within a limited width since ~he
shafts 114 and 116 are inside a narrow frame that has
a width of between substantially 20 and substantially
50 ¢entimetres, said frame extending from the engine
99, which is located at the $ront of the tractor, rear- -
wardly between the front ground wheels 102 to 10~ to
the differential for the rear ground wheels 110 to 113.
The very narrow frame, which is afforded principally by
hollow beams that accom~odate driving shafts, has the
advantage that, if required, more than two rows of
driven ground wheels could be provided. ~hus, in any
- 34 - . . -
1~545Z~3
one of the three embodiments that has been described,
a third row of four or six closely adjacent driven
ground wheels could be provided thus further reducing
the pressure per unit area of contact between each
tyre and the ground surface. Even in very soft or
waterlogged soil, sinkage can thus be reduced to an
extent that does not interfere significantly with
operatlon and it is almost always possible to trans-
form all of the engine output that is available for
that purpose into tractive effort.
Generally speaking, the grip of pneumatic
tyres upon the ground is enhanced if those tyres have
tread patterns which exhibit large teçth and tractors
that are employed in ploughing operations are fre~uent- ~
ly furnished with such tyres. However, pneumatic tyres ~ -
that have tread patterns with teeth o$ large radial ex-
tent are expensive. ~he arrangement shown in Figure 5
of the drawings can reduce this expense because the
pneumatic tyres of the outermost wheels 30 and 33 of
the row of four wheels 30 to ~3 inclusive are tyres
whqse treads have teeth 85 of comparatively small rad-
ial extent, said teeth being, however, relatively close
together around the circumference of the tyre. ~he
teeth 86 of the treads of the tyres of the inner wheels
31 and 32 are teeth of relatively large radial extent
so that said tyres are ~hus of the expensive kind dis-
cussed above, the teeth being spaced apart, however,
around the circumference of each tyre by ~reater distances
than are the teeth 85 o$ the tyres of the wheels 30
- 3~ -
-
1054SZfl
and 33. ~igure 5 of the drawings illustrates the trac-
tor in use in a ploughing operation with one of the
outer wheels 30 travellin~ in an elready ploughed fur-
row whereas the immediately neighbouring wheel 31, that
is of the same overall diameter, travels on unploughed
soil immediately to one side of the furrow. ~he large
teeth ~6 of the tyre of the wheel 31 penetrate quite
deeply into the soil and can transform all or most of
the applied torque into tractive effort. ~he smaller
teeth 85 of bhe tread pattern o~ the tyre on the wheel
30 do not sink into the furrow to any great extent and
are quite adequate for the purpose in view thus making
it unnecessar~ to provide the wheel 30 (or the wheel
33) with a more expensive tyre having the teeth 86 of
larger radial extent. Since the wheel 30 travels m
the already formed furrow~ the plough does not need
to be markedlg offset in position relative to the path
of travel of the tractor and this enables the tractor
driver to steer a straight course without exerting a
strong corrective effort to one side on the steering
wheel 28 because the plough is nearer to the imaginary
substantially vertical plane of substantial symmetry of
the tractor that extends in the direction A than is con- -
vèntional. If the land to be ploughed is very soft,
with the result that the tractor tends to ~ilt to one
side 'Qeyond the inclination illustrated in ~igure 5,
the peripheral surface of the tyre of the wheel 30
from which the teeth 85 project will come into substan-
tially direct co~tact with the ground surface which latter
- 36 -
, . . . , . ... , .. .. ,,, - ...... . . . . . . ............. . ..... .
: . : . - . . ., : :,: . .
10545Z8
will then give a greater degree o~ support. ~iltin~
to a dangerous extent is thus prevented. Since the
tyre of the wheel 30 has a large number of the teeth
85, the tyre is able to transform quite a high torque
into tractive effort as soon as the teeth 85 in a lower
arc of the tyre of significant angular extent have pene-
trated into the soil.
~ he scrapers 67 between the tyres of the wheels
30/31 and tho~ of the wheels 32/33 and also the scrapers
that are provided between the tyres of similarly disposed
wheels in the other embodiments act to scrape off mud and
lumps of soil from the immediately neighbouring sides of
the ~yres of the wheels concerned. It can be seen from
Figure 2 of the drawings that each scraper 67 covers the
whole radial extent of the two tyres with which it co-
operates so that the sides of the tyres in question are
kept free of large accumulations of mud throughout
operation of the tractor. Owing to the arcuately curved
formation of the scrapers 67 that initially ~as seen in
side elevation - Figure 2) extend substantially vertic-
ally downwards and then forwardly towards the common
axis of rotation of the rear ground wheels, there will
be a tendençy for mud and the like scraped from the
tyres to travel upwardly along the scrapers 67 until
it moves outwardly beyond the treads of the tyres of
the wheels concerned. Much of the mud will drop away
to the ground surface when it reaches this location,
or previously, and any that does not do so will be dis-
placed rearwardly along the bottom of a corresponding
- 37 -
1~54528
curved guide 125, said guides 125 being substantially
horizontally disposed but, as can be seen in Figure 2
of the drawings, initially projecting rearwardly and
upwardly to a small extent from the tops of the corres-
ponding scrapers 67 to terminate in downwardly bent-over
portions. ~he guides ~25 are rigidly secured to the
support lugs 69. ~he spring-loaded mounting of the
scrapers 67 enables them to deflect about the corres-
ponding pivot pins 68 to avoid damage in the event of,
for example, a stone o~ the like becoming jammed bet-
the
ween/tyres of the corresponding wheels 30/~1 or 32/33.
~he rims 64 of the towing and scraping member
62 thab is rigidly secured to the bottom of the hous- :
ing 4 lie very close to the inner side surfaces of .
the tyres of the wheels 31 and 32 and mud and the -
like scraped from those side surfaces by the rims 64
will sooner or later drop back onto the ground surface
between the wheels 31 and 32. There is a tendency for
mud and the like scraped off by the rims 64 to mo~e
away from the tyres concerned towards the centre of
the member 62 so that, generally speaking, when that
mud falls back to the ground surface, it will be clear
of contact with the tyres of both of the wheels 31 and
32. ~he rims 64 stiffen the plate-shaped towing and
scraping member 62 and tend to prevent bending of the
latter when the member is used as a towing hook by
employing the hole 63 that is formed therein. In
particular, the rims 64 tend to prevent upward deflec-
tion of the member 62. ~he scrapers 65 that ca~ be
- 38 -
1~545Z~I
seen best in ~igures 4 and 5 of the drawings are ar-
ranged to shed adhering mud and the like from at
least the inner teeth 86 of the tyres of the two
wheels 31 and 32 because the plates 66 at the ends - :
of the scrapers 65 are located in, or just beyond,
the median planes of the tyres of the wheels 31
and 32 that extend parallel to the direction A.
The end plates 66 are employed for the connection
of implements or tools during the use of the tractor
and, if desired, the scrapers 65 can be extended out-
wardly beyond them to embrace substantially the
whole of the width (thickness) of the tyre of each
of the two wheels 31 and 32. ~he scrapers 65 co-
operate with the treads of the tyres of the wheels
31 and 32 in the manner of butter curlers and the
removed mud curls away downwardly and rearwardly
behind the scrapers 65 to fall back to the grou~d
behind the tyres.
In the embodiments of ~igures 7 to 9 of the
drawings, the member 62 is not rigidly secured to
the tractor~frame 1 but forms part of the rear
lifting device or hitch of the tractor, the member
~2 being provided at the back with the scraper 89
which scraper extends effectively throughout the
width of the treads of the tyrçs of the wheels 31
and 32 or 110 and 111. ~he scraper 89 may be extend~ -
ed laterally, if desired, to co-operate also with
the treads of the tyres of at least the wheels 30 and
33 or 112 and 113. ~he scraper 89 also serves as a
- 39 -
- \
1~54SZfl
support for the end plates 90 to which an implement
or tool can be connected employing the eyes 91. Scra-
pers that are substantially identical to the previous-
ly described scrapers 67 may be arranged between the
closely neighbouring tyres of the pairs of ground
wheels in the embodiments of ~igures 7 to 9 of the
drawings and, in the embodiment of ~igures 8 and 9, --
the fork 97 that lies between the tyres of the wheels
102 and 103 may also carry a laterally disposed scra-
per (not shown) for keeping the treads of the tyres
102 to 104 inclusive clean. As previously mentioned,
the rear scraper 89 may be increased in width so ~hat
it will co-operate also with the treads of the tyres
of the wheels 112 and 113~
In the embodiment of Figures 1 to 6 of the
drawings, the engine 7 is located above and between
the $ront ground wheels 6 so that the pressure of
those wheels on the ground is quite high and it can
be useful, as described, to arranged them so as to be
drivable. However, in order that the pressure of the
rear wheels 5 upon the ground should not be too low,
ot~er parts of the tractor are arranged near to the
common axis of rotation o$ the rear ground wheels.
Thus, the driving cabin 18 and the driving seat 27
are arranged substantially directly above the axis a~'
rotation of the rear wheels 5. In the embodiment of ;
Figures 8 and 9 of the drawlngs, the engine 99 is -
located in front of the ground wheels 102 to 105 with
respect to the direction A and thus tends to reduce -:
":
_ 40 -
- . : . . . ... : . ~ . . .. . .. .
1~5~5Z~
the pressure of the rear wheels 110 to 113 upon the
ground surface. In order to compensate for this, the
driving cabin 120, the driving wheel 117, the controls
of the tractor and the rear lifting device or hitch
thereof are all located above, or close to, the com-
mon axis of rotation of the rear ground wheels.
~ he driving cabin 18 of the embodiments of
~igures 1 to 7 of the drawings contains the driving
seat 27 and also the cabin floor portion 19 which is
at a lower level. The distance between the cabin
floor portion 19 and the roof 23 of the cabin is such
that a person whose height is not more than substan-
tially 1.75 metres aan stand upright in the cabin and
preferably at a location alongside one of the doors
20 so as not to impede bhe forward view in substantial-
ly the direction A of an operator occupying the seat 27.
~ he fro~ a~d rear portions 94 and 95 of the
frame of the tractor that has been described with
reference to Figures 8 and 9 of the drawings are rela-
tively pivotable about the substantially vertical ~xis
that i5 de~ined by the strong pivot 96 and relative
angular displacement of the two frame portions 94 and
95 about said axis enables the tractor to be qteered
from the wheel 119. Vehicle steerability in this gen
eral manner is known ~er se and , accordingly, the parts
that enable it ~o be effected are not illustrated in
~igures 8 and 9 of the drawings and do not need to be
described for the purposes of the present invention~
~he overall diameter of each of the wheels 102 to 105
- 41 -
.. . , . - . , ,
1~3545Z8
and 110 to 113 of the tractor of Figures 8 and 9 of the
drawings is substantially 150 centimetres and the trac-
tor, when equipped with eight ground wheels as illustra-
ted, has an overall width which is not greater than
3.0 metres and which is preferably substan~ially 2.5
metres. The tractor can thus travel along public
roads without restriction.
, . . . ~ ~, ~ .,
.. , .: . ~ .. .:~ . . ..
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