Note: Descriptions are shown in the official language in which they were submitted.
2~)3~5~
Title: "Vehicle"
This invention relates to a vehicle having a first pair of ground
engageable means carried on a first oscillating member which is pivotable
about a generally horizontal axis e.g. horizontal or inclined to the horizontal
up to about 15 relative to a second oscillating member which carries a
second pair of ground engageable means. The generally horizontal axis
permits the pairs of wheels to twist relative to each other when driving over
uneven ground so that the pairs of ground engageable means can conform to
the shape of the ground.
Such vehicles are known which have at least one of the first and second
lû oscillating members provided by an "oscillating axle". That is, an axle which
is connected to a respective chassis part by means of a connection which
permits the axle to oscillate relative to the chassis part about a generally
horizontal axis e.g. horizontal or inclined to the horizontal up to about 15 toenable the vehicle to travel over rough terrain, the chassis part being rigid
with a further chassis part about a generally horizontal axis. Alternatively,
the chassis parts themselves maY be connected for pivotal movement about a
generally hor ~ontal axis with the wheels being carrled by the respective
chassis parts without provision for pivotal movement about a generally
horizontal axis.
2û More particularly, but not exclusively, the invention relates to a vehicle
comprising a front chassis part and a rear chassis part which qre articulated
for steering about a generally upright axis e.g. vertical or inclined to the
vertical up to about 10. Such a vehicle will hereinafter be referred to as "an
~; ~ articulated vehicle".
- ~ 25 Particularly when such an articulated vehicle is provided with a loaded
work irnplement which projects forwardly or rearwardly of the chassis parts,
stabilisation of the vehicle, especially when cornering by articulating the
front and rear chassis parts relative to one another, is a design consideration.However, the very nature of such an oscillating axle or oscillating chassis
3û parts can contribute to instability of an articulated vehicle, especially on
cornering since, particularly when the vehicle has a loaded work implement
projecting from a chassis part, a moment is produced tending to overturn the
vehic le.
- ~ .
~ : .
` ~0!~32~4
2--
An ob]ect of the invention is to pr^vide a new cnd improved vehicle.
Accor~ing to the present invention ~e provi<Ze a vehicle comprising a
first pair of grourd engageable means carried on a first oscillating member
which is pivotable about a generally horizontal axis relative to a second
5 oscillating member which carries a second pair of ground engaaeable means
and a stabilising sYste-n, the stabilising systern comprising fluid operated
actuator means, c~nnected '~etween the oscillating members to control
oscillation therebehveen about said generally horizontal axis, passage means
to enable fluid to flo to and from a chamber of the achlator means in
lû response to oscillation of the members und valve means to control the flow offluid along the pa.ssage means in a direction to control oscillation between
said members, said valve meons being actuated by a co~trol signal depenctent
on a ground engaging force transmitted by o ground engageable means of the
vehicle.
Flow of fluid through the passage means from a chamber of the
actuator means, which is operative to control rising of one of the first pair ofgrou~d engageable means carriect hy the f7rst oscillating member, is
controlled by a valve means provided with a control signal derived from said
force transmitted hy one of the seconrl pair of ground engageable means
2û which is diagonally opposite, as herein defined. to said one of s aid first pair
of ground engageable means.
By 'diagonally opposite' we mean a ground engageable means ~hich is
disposed on the opposite side of a fore and aft line of the vehicle~ and which is
disposed towards the opposite end of the vehicle to the end adiacent which is
disposed said ground engageable means which is tendiny to rise.
The valve means maY pr~vent transfer of fluid relative to the actuator
;;~ chamber to control said oscillation.
Alternatively, the valve means may permit transfer of fluid relative to
the actuator chamber against a resistence to fluid flow to control said
oscillation.
The invention is particularly, ~ut not exclusively, for use where the
vehicle is an articulated vehicle as herein defined.
In this case the flo~l of fluid is controlled so as at leost to resist
relative pivotal movement bet~A~een the osci!lating members to counteract
~- ~ 35 rising of one oscillating member rela~ive to the other on the same sid~ as the
direction in which the one oscillating member has been articuluted for
~; steering.
:.`
: `'~``' .`
` ' '
-' :. . .
"''''" : '; ' , '
Z003~54
3--
The oscillating members may comprise, ;n a preferred embod1ment, an
oscillating axle and an associated chassis part but may comprise two
oscillating chassis parts.
Where the oscillating member is an osciilating axle, and the vehicle is
an articulated vehicle, the oscillating axle may be provided either on a front
or rear chassis part, or both the front and rear axles may be oscillating axles,in which case both the front and rear axles may have a stabilising system if
required.
It will be appreciated that as the vehicle moves over the ground,
lû particularly when the vehicle is cornering, the load carried by the loading
implement affects the stability of the vehicle. Hence by "load" we mean the
effect of the load on the stability of the vehicle.
The vehicle may have a boom carrying a loading implement such as
forks or a bucket, which boom and loading implement may be operated by a
power system, such as a fluid operated system, to enable the loading
implement to be loaded. However, the invention may be applied to any other
type of vehicle which has an oscillating member.
A single acting fluid operated actuator may be provided on each side of
the axis of oscillation of the members, a passage means connecting each
actuator chamber to a source of fluid under pressure and the valve me~ns
controlling flow of fluid along the passage means.
In an alternative, a double acting fluid operated actuator may be
provided on one or each side of the axis of oscillation of the members, the
passage means connecting the chambers on opposite sides of the or each
actuator to a source of fluid under pressure and the valve means controlling
flow of fluid along the passage means.
In each case the passage means may connect the actuator chambers
together so that fluid ejected from one chamber is transferred towards the
o~her and vice-versa.
3û hleans may be provided to supply flu;d to an actuator to force the
associated side of an oscillating member carrying a ground engageable means
downward ly.
The fluid may be supplied from a hydraulic circuit which supplies
hydraulic fluid to a loader operating means of the vehicle.
Said control signal may be provided by a sensing meGnS adapted to sense
a parameter which varies in dependence on variation in said ground engaging
force.
2~)325A~
,
--4--
Said sensing means may provide an electrical control signal.
Said sensing means may provide a fluid control signal.
Said sensing means may be operable to sense deflection of a part of an
element of a rear axle of the vehicle having sGid ground engageable means
mounted thereon.
Said sensing means may be operable to sense movement of a part
carried by cn element of the rear axle of the vehicle having said ground
engageable means mounted thereon.
Said sensing means may be operable to sense strain of a chassis part on
lû which is mounted a part of a rear axle of the vehicle having said ground
engageable means mounted thereon.
Said element may comprise a casing of the axle.
Said deflection may be sensed by sensina the distance between a part of
said element of the axle and a reference member connected in cantilever to
another part of the axle or to the chassis part.
The reference member may be disposed within the axle casing.
The reference member may be fixed to the axle adj~cent the .-nid-po nt
thereof and the reference member may extend in cantilever and parallel to
the axis of rotation of the ground engageable means carried by the ~xie.
2û The distance may be measured by measuring the movement of a probe
which is movably carried by a mounting member fixed to the axle and the
probe being movable with the reference member.
~` ~ Means may be provided to ensure that the axle and reference member
are uniformly heated to avoid significant variation in said distance sensing
due to differential thermal expansion.
Means may be provided to distribute oil within the axle over the whole
or substantially the whole of the internal surface thereof and of the
reference member so that, in use, the temperature of the axle and reference
` member is uniform or substantially uniform.
; ~ 3û The reference member may be tubular, one end of the tube being fixed
to the axle and the distance between the axle and a portion adjacent the
- ~ other end of the tube being sensed.
: The tubular reference member may be provided with openings at least
in an upper part thereof to enable oi1 to pass therethrough.
. ~ 35 The tubular reference member may encircle a drive shaft to the ground
.,
engageable means and the shaft may drive an oil distributing means to
:' ~
. .
': ',
.:. -
` 2C03ZS4
,,
distriblJte oi! onto an upper part of the inner surface of the tub~ and, throughsai~i openings, onto the axle casing.
Atternatively the sensing means rnav comprise a fluid operated ram,
connected so as to be driven by relative movement between a part of the rear
5 axle having said ground engageable means mounted thereon and a chassis
part, displacement of fluid relative to said ram providing said control signal
to the valve means.
The invention will now be described with the aid of the accompanying
drawings in which:
FIGURE I is an illustrt~tive side vie~ of a vehicle which embodies the
invention.
FIGURE 2 ts a vie-~ looking forwards at the rear of the front axle of the
vehicle of Figure I showing part of a stabiliser system according to the
invention,
FIGURE 3 is a diagrammatic illustration of the hydraulic circuit of the
stabilising system of the vehicle of Figures I and 2,
FIGURE 4 is a c!iagrammatic illustration of the electric circuit of the
stabilising system of Figure 3 showing the vehicle in plan view,
FIGURE S is a diagrammatic illustration of an alternative hydraulic
2 0 circuit,
FlGU~E 6 is a fragmentary cross-sectional view through part of the
rear axle of the vehicle of Figure I, and
FIGURE 7 is a fragmentary view showing a modi'ication of the vehicle
shown in Figure 1.
Referring f~rst to Figure 1, a vehicle 10 of the articulated type has a
vehicle body I I comprising a front chassis part I ' and a rear chassi~ part 13,and a pair of loading arms 14 which together comprise a loading boom~
¦ ~ carried on the front chassis part 12.
The vehicle lû is driven and the loading arms 14 are controlled, from
within an operator's cab IS which is mounted on the rear chassis part.
The body 11 carries two pairs of ground engageable means comprising
~ wheels 17,18. The wheels 17 are termed hereinafter "the front wheels" and
I are carried on a ~ront axle 30 on the Front chassis part 12. The wheels 18 are
termed hereinafter "the rear wheels" and are mounted on a rear axle 2ûO
carried by the rear chassis part 13.
An engine to provide power to drive the vehicle 10 and a hydraulic
operating system of the vehicle 10, is mounted beneath a bonnet 19.
Z~32~;4
--6--
The loading arms 14 are pivotally mounted at one end at 20 to the front
chassis part 12, cnd carry at an opposite end a loading implement comprisin~
in this example, a loading bucket 22. The loading arms 14 can be moved about
a pivot 20 by a pair of hydraulic actuators 23 connected in a loader lift arm
5circuit, although only one of these can be seen in Figure I of the drawings.
The bucket 22 can be pivoted relative to the loading arm 14 for movement
about a generally horizontal axis 25, by a further pair of hydraulic actuators
26 (only one of which can be seen) mounted between the loading arms 14 and
the bucket 22.
10Thus the vehicle 10 can be loaded and unloaded by manipulating the
arms 14 and bucket 22, as is well known in the art. If desired, any other
means for manipulating the arms and the bucket may be provided.
The vehicle 10 can be steered by articulatina the front chassis part 12
relative to the rear chassis part 13, about a generally vertical axis 27, by
15means of linear hydraulic actuators which are provided to effect this
-~ articulation, although alternatively any other hydraulically powered or other
slewing -neans could be provided.
Referring now to Figure 2, there is shown the front axle 30, which in
;J52 carries the front wheels 17, although the wheels 17 themselves are
2ûomitted from Figure 2.
The wheels 17 are mounted on hubs 31 at each end of the axle 30 and
the hubs 31 are driven via half shafts ~Nithin the axle 30 from a crown wheel
and pinion sear rnounted in a housina 32 of the axle, drive being transmitted
thereto from a gearbox G via drive shafts H.
25The axle 3û is of the oscillating type and is mounted relative to the
front chassis part 12 by trunnions 34 received by bushed openings of the
chassis front part 12 so that the axle 3û may oscillate about a generally
I horizontal pivotal axis 35. There is a tendency for this oscillation to permit
of overturning of the vehicle in certain circumstances. For example, when
30the loadin~ bucket 22 is transporting a load and the chassis parts have been
articulated about the axis 27 for steering, the reaction with the ground
preventing overturning occurs at the contacting point of the inside rear wheel
18 and the pivot axis 35 at the centre of the axle 30. The load being offset,
in the direction of steering, frorn a projection of a line joining these points,35creates a turning moment.
To stabilise this oscillation, an actuator means comprising a pair of
single acting hydraulic actuators 138,139, is mounted between the axle 30 and
,~`' ~:
. .
~' . '' '; .
.
. ..... - :
. ~:
` 200325
7-
the front chassis part 12 externally of the chassis side plates 12a of the firstchqssis part 12. One actuator 138 is provided to one side of the axis 35 and
the other actuator 139 is provided on the other side of the axis 35. The
connections between the actuators 138,139 and the axle 30 and between the
actuators 138,139 and the front chassis part 12, permit of pivoting movement
about the axis 35 as the axle 30 oscillates.
Referring now to Figures 3 and 4, the actuators 138~139, are each part
of an axle stahilisin~ ~ystem I40 of the vehicle 10.
The cctuators 138, 139 have a piston 138a, 139a, slidable in a cylinder
138b, 139b to provide a variable volume chamber 138c, 139c. The chambers
138c, i 39c are inter-connected by a passage means 141 and fluid to the
stabilising system is provided from a make-up line 150 throuah which
hydraulic fluid is fed to the passage means 141 from a hydraulic pumpP
provided on the vehicle which also provides fluid under pressure to the other
services S of the vehicle, such as the loader arms The pressure in the lir-e
150 is reduced to a low pressure e.g. 14 8ar by a pressure reducing valve 152
and limited to a slightl~ higher pressure, e.g. 17 8ar by a pressure releose
valve 153.
The free f!c~ ^f fluid c!ong the passage means 141, to transfer fluid
relative to the respective actuator chamDer, is controlled hy a respective
valve 142, 143. one of which is associated with each of the actuators 138,
13Q. The valve 142 7s provided on the chassis adjacent to the actuators 138,
129 but may be incorporated as an integral part of the actllators if d~sired.
The valves 142, 143 are of a known type which can be opened, to permit of
free passage of fluid therethrough, or closed, to prevent of passage of fluid
; ~ therethrough, in a direction away from the associated actuator, by means of
an electrical control signal supplie~l to the valve. The valves are provided
with a suitable check valve arrangement which allows fluid to flow through
the valve 142, 143 towards the associated actuator at all times. In addition,
3 û check valves 142', 143' are provided to prevent excess pressure being
developed in the actuators 138, 139.
The passage means 14 i is also provided U/ith a restrictor and check
vaive assemblies 144, 145 associated with each actuator 138, 139
respectively, to permit of restricted flow of fluid away from the associated
actuator and free flow of fluid in the direction towards the associated
actuator.
`:
:,
`
:
:
.
2C~3254
,
The electrical control signal is provided by a suitable electrical circuit
which includes sensors 170, 171 which sense the load on each rear wheel 18a7
1 8b as hereinafter to be described.
The electrical control circuit includes a controller 176 comprising a
5 micro-processor and is arranged
a) to close the valve 142 when the sensor 170 associated with a
diagonally opposite rear wheel 18a senses that the load on the rear wheel 18a
has fallen below a predetermined level whilst the valve 143 is signalled to
remain open by the sensor 171 associated with a diagonally opposite rear
1 û wheel 1 8b, senses that the load on the rear whee~ 1 8b is above a
predetermined level, or
b) to close the valve 143 when the sensor 171 senses that the load on
the diagonally opposite rear wheel 18b has fallen below a predetermined level
whilst the valve 142 is signalled to remain open by the sensor 17û associated
with the diagonally opposite wheel 18a, sensing that the load on the wheel
18a is above a predetermined level.
It is preferred that the load which causes a previously closed valve to
open is a higher load than that which caused the valve to be closed. The
higher load to cause opening of a previously closed valve avoids operation of
~ 2û the stabilislng system when ,he vehicle encounters a ternporary unstable
i ~ condition, for example if a rear wheel encounters a pothole or other localised
l~ surface irregularity.
' ~ The switches which are used to provide the sensing means to controller
176 may comprise a set of relays instead of a micro-processor.
Operation of the stabiliser system 142 will now be described.
As the vehicle travels, normally the front axle 30 will osciJlate and
fluid will be expelled from an actuator 138 or 139, as the associated axle side
risest and be fed to the other actuator 139 or 138 respectively, with the flow
; being restricted by the associated restrictor and check valve assembly 144,
145 respectively, to limit the speed of oscillation of the axle 30.
As the vehicle corners, by articulating the front chassis part 12 relative
to the rear chassis part 13 then under certain circumstances, for e~ample
when the loader arms are extended and/or carry a heavy load, the outside
rear wheel tends to become unloaded and can, in the absence of the present
invention, lift from the ground. In accordance with the present invention,
when the load on the outside rear wheel falls below a predetermined level,
.
:-
''
.~ .
~,
. . .
.
, ~ `' .
- ~; : ;
` `- ' ' ~
32~;4
g
this is sensed by the relevant sensor 170, 171 to provide a signal to the
diagonally opposite control valve 142, 143 respectively to cause that valve to
be closed and hence prevent flow of fluid from the associated actuator 138,
139 and therefore prevent the associated axle side rising, thus preventing the
5 load on the diagonally opposite rear wheel falling further and hence
preventing the rear wheel from lifting from the ground. The check valve
permits fluid to flow to the rqm if the axle assembly oscillates in the reverse
direction to cause the actuator to be extended.
If desired, in a modification shown in Figure S, the electrical circuit
provides a signal to the valves, 142 or 143 to close the relevant valve to
prevent the fluid flow therethrough and to open a further valve 142a or ~43a
to supply fluid under pressure, from the loader lift arm hydraulic circuit C, inwhich the actuators 23 are connected, to the associated ram 138, 139.
Consequently, the associated side of the axle is forced downwardly and thus
actively maintains the diagonally opposite rear wheel on the ground.
It will be appreciated that as the vehicle is loaded, for example as soil
is loaded in~o the bucket 22, the pressure in feed lines SO feeding hydraulic
fluid to the actuators 23 to lift the loading arm 14 will increase. This
increase in pressure in the loader lift arm circuit C is transmitted to the
2û actuators 138, 139 when a valve 142a, 143a is opened and the restoring force
will thus be increased by an amount depending upon the magnitude of the
load.
Thus the restoring force of the oscillating axle 30 relative to the front
chassis part 12 will change depending upon the magnitude of the load carried
by the loader arrn. The greater the load, the more pressure is provided via
the valves 142a, 143a and so the greater the restoring force which is applied
to the oscillating axle 30.
If the pressure obtaining in an actuator 138, 139 due to a load imposed
thereon as a result of oscillation the axle 30, exceeds the pressure obtaining
3û in the loader lift arm circuit hydraulic fluid will not flow from an actuator
138, 139 to the loader lift arm circuit C because of the provision of a check
~ i valve means in the valves 142a and 143a, thereby avoiding any possibility of
`~1 oscillation of the axle occurring as a result of the pressure ;n the actuator
- 138, 139 ccusing lifting of the loader arnns.
The electric circuit is preferably arranged so that the valves 142, 143
(and 142a, 143a when provided) occupy the positions illustrated in Figures 4
.,
` 2~3Z5~
-10-
and 5 when no electric current is supplied thereto, thereby biocking flow of
fluid from the rams, should the electrical supply fail. Hence the arrqngement
is "fail-safe".
In a further modification the electrical circuit may provide a signal to
the valves 142, 143 and the valves may be arranged to permit fluid flow
between the actuators 138, 139, but against a resistence sufficient to
stabilise the vehicle as described hereinbefore.
The pump P supplying fluid under pressure by the pipe IS0 may be an
independent pump provided for the purposes of the stabilising system and
independent of the fluid circuit for the loader arms 14 or the fluid in the pipe150 may be supplied from the loader arm circuit.
Instead of the pair of single acting actuators 138, 139, one disposed on
either side of the oscillating axis 35, the actuator means may comprise a
double acting actuator which may be provided on one or each side of the axis.
In this case, the passaae means connects the chambers on opposite sides of
the piston of the or each double acting actuator so that the
stabilising system operates substantially as described above, but with suitable
arrangements provided to compensate for the different volumes of the two
chambers due to the presence of a piston rod in one chamber. For example, a
valve means may be associated with a chamber provided at each side of the
piston of the or each double acting actuator rather than with each of a pair
of single acting actuators.
In the embodiments described above, the means for sensing the load on
each rear wheel 18a, 18b comprises a specially adapted rear axle 20û
comprising a central housing part 2û I which houses a conventional
differential drive 202 and crown wheel and pinion. A pair of generally
tubular casings 2û3 are bolted to opposite sides of the housing 2ûl. As best
i ~ shown in Figure 6, each casing 203 has at its outer end an inner race 2û4 of a
roller bearing 205, an outer race 2û6 of which mounts a hub 207 and a wheel
18a, or 18b is mounted on the hub 207. The hub 207 is driven by a half shaft
208 which extends within the casing 2ûO parallel to a central axis X-X
thereof and is adapted, at its inner end, to be driven by the differential 2û2.
The half shaft 208 has a sleeve 209 fixed thereto which is engaged with a
; ~ multi-plate brake 210 disposed within an inner part 211 of the casing 2û3.
~ 35
.~.
.~
.,
~.
,
`
- Z0~)325~
-I 1-
Also mounted within the casing 203 is a tubular reference member 212 which
is fixed to a flange 213 mounted within the casing 2û3. Thus the tubular
reference member 212 is mounted in cantilever on the flange 213. A distance
sensing device 214 is bolted to a part 22û of the casing 203 and has a probe
215 which engages a surface part 216 of the tube 212 adjacent a free end 217
thereof. In the present example the measuring device 214 comprising a
voltage splitting potentiometer, the movable contact of which is moved in
accordance with the position of the probe 215.
If desired, any other form of ser-sing device may be provided, such as a
lû variable inductance or capacitance device, a strain gauge or an optical
sensing device.
The tube 212 is provided with three rows of circular apertures 218, the
central row being disposed at the top of the tube 212 and the other two rows
being disposed as shown in the upper half of the tube. The tube is also
provide with two further circular apertures 21~ at the bottom adjacent the
inner end of the tube.
In use, as the load on a wheel 18a or 18b varies, it will cause the
associated axle casing 203 to deflect so that the distance between the part
216 ^f +Ihe reference tube 212 and the adiacent part 220 of the casing 203 will
2û vary since the reference tube 212 will not deflect with variation in wheel
load7 whilst the casing will. There-fore, by measuring the change in the
distance between the parts 220 and 216, a measure of ~he ground engaging
force transmitted by the wheel 18a or 18b is achieved.
In conventional manner the casing 203 is partially filled with oil and, in
use, the oil heats up and consequently the part of the casing 203 and the tube
~; 212 immersed in the oil would be of a higher temperature to the parts of the
casing 203 and tube 212 not immersed in the oil. Due to differential thermal
expansion effects, the accuracy of the load measurement will be affected
since the distance between the two parts 220 and 216 would vary due to
thermal differential effects, irrespective of variation in load.
To avoid this problem the apertures 218 are provided, together with a
' ~ paddle device 221 fixed to rotate with the half shaft 2û8 and which serves to
throw oil into contact with the upper pqrt of the tube 212 and, through the
apertures 218 into contact with the upper surface of the casing 203, thus
causing the temperature of the tube 212 and casing 203 to be substantially
uniform throughout their circumferential extent, thereby avoiding the above
mentioned differential thermal expansion effects. It has been found that
.
32~;4
_ -12-
when the vehicle is stationary, so that the oil falls to the bottom part o~ the
casing 218 and the paddle 221 is inoperative, the upper parts of the casing
203 and of tube 212 cool similarly so that on cooling there is no unacceptable
variation in the spacing between the parts 216 and 220.
It has been found that if the reference member 212 is cut away
completely in an upper part, for example, above the centrul axis of the tube,
so that the majority of the tube, except for cyl7ndrical parts, is, for example,of semi-cylindrical shape, then whilst the paddle 212 serves to keep the axle
casing 203 at a uniform temperature in service and the reference member
1û 212 is maintained at the same temperature, since the majority of it is
immersed in the oil in the lower part of the casing 203 so that differential
thermal expansion effects are not a problem during normal use of the vehicle,
when the vehicle was stationary then the reference member 212 stayed at the
same temperature as the oil whilst the upper part of the casing 203, which is
not immersed in the oil cooled causing differential thermal expansion effects
to occur, leading to a variation in the distance between the parts 220 and
216. It has therefore been found necessary to make the reference member
212 of the above described configuration where there is a portion of the wall
of the tube above the central axis of the tube or at least above the part of
2û the tube which is normalh~ in contact with the oil, so that on cooling a similar
distortion pattern occurs in the upper parts of the casing 203 and reference
member 212.
The apertures 219 are provided to enable oil to pass between the casing
203 and the interior of the tube 212 to enable oil to be circulated through the
brake 210. If desired, the reference member 212 may be provided with
apertures throughout its circumference and indeed may comprise a generally
perforated member.
Although a generally cylindrical tubular member has been described as
the reference member 212, if desired the reference member 212 may be of
other configuration, for example it may comprise a latticework construction,
or it may comprise a plurality of parallel members, for example, three
members arranged in a equilateral triangle or other conf7guration with
appropriate connecting members, or may be of any other desired
configuration consistent with avo;ding the above described differential
thermal expansion effects.
If desired, other means for detecting deflection of the axle casing 203
may be provided. For example, a reference member may be provided fixed
ZC~3~54
,
-13-
relative to the housing 201 and extending in cantilever parallel to the axis X-
X but disposed externally of the casing w ith appropriate sensing means
similar to the means 214 described hereinbefore provided to sense variation
in the distance between a part of the reference member adjacent a free end
5thereof and an adjacent part of the casing 203. Such an externally disposed
reference member is not, however, preferred since it is liable to damage and
to be interfered with by foreign bodies.
If desired, whether provided internally or externally, the reference
member may be mounted in cantilever at the outer end of the casing 203 and
lûextend inwardly so that its free end is adjacent the housing 201. In this casea sensing means similar to the sensing means 214 would be provided adjacent
the housing 201.
Further alternatively, the reference member may be mounted in
cantilever at any desired position along the length of the casing 203 and may
15extend therefrom so that its free end is directed inwardly or outwardly
relative to the housing 201 so long as the reference member is of sufficient
length for there to be a change in distance between it and the casing for
accvrate measurement.
If desired, any other suitable sensor to sense the load ^n each rear
2ûwheel 18a, 18b may be provided. For example, as shown in Figure 7 a
displacement sensing means 180, such as a transducer or micro-switch, senses
displacement d of an upper end 181 of a bar 182 fixed, at its lower end 183,
for example by welding, to a bracket 184 carried by the axle 173.
Alternatively, as shown in dotted line in Figure 4, the sensors may
25comprise a strain gauge 170', 171' provided on flanges 172 that mount the
rear axle 173 on the rear chassis part 13.
Further alternatively, instead of providing an electrical circuit to sense
the loqd on the rear wheel and to provide a signal to the control valve 142,
143, (and valve 142a, 143a, when present) if desired, a pair of single or double3ûacting hydraulic rams or one double acting hydraulic ram may be connected
between ~he rear chassis part and the rear axle, which may itself be mounted
for oscillation on the rear chassis part and the flow of fluid from and/or to
these rams may be used to provide a signal to control hydraulically actuated
valves corresponding to the electrically operated valves 142, 143 (142a,
3 5 143a).
In the embodiments described, the stabilising system is applied to an
oscillating member comprising an axle. Where rigid axles are provided on an
,
~' . . .
2(~ S~
-14-
artlculated vehicle, the stahilising system mav be provided betl~een the
osciilating chassis parts in which case the oscillating member wau1d be one of
the chassis parts, and the actuator or actuators would be connected b~tween
the chassis parts. If desired each of the first and second pairs of wheels may
be carried on an oscillating member which can pivot relative to an associated
chassis part cnd the c! assis parts may themselves be pivotally inter-
connected about a generally horizontal axis in which case an appropriate
number of stabilising systems may be provided for each pair of oscil1ating
parts. Appropriate sensing means to sense the ground engaging force
transmitted by an appropriate ground engageable means of the vehicle. e.g.
one diagonally opposite to the respective actuator.
Various modifications may be made without departing from the scope of
the invention.
It will be appreciated that although the stabilising system 140 is
described in relation to an articulated loading vehicle, the invention may be
applied to any other load carrying vehic1e, and many other types of
articulated and non-articulated vehicle as required which may have an
oscillating axle.
As described, the vehicle lû only has a stabilising system associated
with the axle 30 carried on the front ground wheels 17, which is an oscillating
axl~. The axle carrying the rear ground wheel5 18 is rigid. However, in
another type of vehicle, both the axles carrying the front wheels 17 and the
rear wheels 18 maY he of the oscillating type and may each have a stabiiising
system associated therewith.
Alternatively, if a rear axle ~ere of the oscillating type and the front
axle rigid, only the rear axle would require a stabilising system. In each case
a control signal dependent upon the load carried by a suitqble wheel of the
vehicle is provided.
~Nhereas, preferably, in a vehicle such as a vehicle shown at 10 in
Figure 1, the axles carr~ing the front and rear wheels 17, 18 are driven so
that the vehicle is a four-wheel drive vehicle, it will be appreciated that the
stabilising system may be applied to a vehicle in which drive is transmitted
through only two wheels so that the hubs 21, for example, may not he driven.
Where the invention is applied to a vehicle which is not of the
articulated type, but has an oscillating axle, the huh 31 of the ~ront wheels
and/or the corresponding huhs on the rear wheels may be movable to effect
steering of the vehicle.
, :, : :
!,
.
` 21~3~54
-15-
Whilst in the il lustrated embodiments a single wheel is mounted
adjacent the end of each axle, if desired a plurality of wheels may be
provided adjacent tne end of each axle. For example, there may be two
wheels side by side rotating about the same axis. Alternatively there may be
5 two wheels disposed in tandem, i.e. rotating about axes which are parallel andspaced apart in a fore and aft direction of the vehicle; in such a case the
wheels may be carried on a sub-frame mounted on the axle and again each
such wheel may have another wheel or wheels disposed side by side. Further
alternatively the vehicle may be provided with endless tracks, commonly
10 known as "caterpillar tracks". A discrete endless track or tracks in tandem
and/or side by side may be provided adjacent the end of each axle or an
endless track or tracks may be common to the ends of the axles on each side
of the vehicle. The term "ground engaaeable means" is used herein to
encompass all such arrangements.
Although the actuators described herein are linear actuators if desired
other forms of Gctuator may be provided such as rotary actuators.
The features disclosed in the foregoing description, or the following
claims, or the accompanying drawings, expre.sed in their specific forms or in
terms of a means for performing the disclosed function, or a method or
20 process for attaining the disclosed result, or a class or group of substances or
compositions, as appropriate, may, separately or in any combination of such
features, be utilised for realising the invention in diverse forms thereof.
: :
:~:
:
