Technical Field
[0001] This invention relates to frames for supporting implements on a vehicle and more
particularly to such frames which are semi-integrated into an industrial vehicle equipped
with earth handling implements fore and/or aft.
[0002] An example of such a frame is a frame for supporting a front end loader and a rear
mounted backhoe on an industrial tractor.
[0003] Implement frames for industrial tractors may be broken down into three catagories.
The earliest loaders on agricultural tractors were supported by attachable and detachable
frames connected to the tractor chassis and dependent solely on the strength of the
tractor chassis for their load carrying capability. The second class of frame-is the
semi-integrated which is permanently attached to the tractor chassis and particularly
the axle housing while having sufficient structure in itself to partially support
the implements attached thereto and absorb the loadings placed on the implements thereby
reducing the loads on the tractor chassis. The third class of implement frame is the
integrated frame which consists of a frame fabricated from the start to receive vehicle
components such as axles, differential, transmission and engine, all of which are
supported from and by the frame which is the support unit for all other components
and assemblies including the vehicle wheels.
Background Art
[0004] Difficulties have been found in producing a semi-integrated frame which is capable
of withstanding the forces imposed on the frame by for example, the operation of a
front end loader and a rear mounted backhoe without resorting to excessively heavy
frame constructions.
[0005] Although certain previous constructions have tackled the problem of the bending loads
imposed on the frame, particularly during the use of a front end loader, no previous
constructions have addressed themselves to the problem of the torsional loads imposed
on the frame.
Disclosure of Invention
[0006] It is an object of the present invention to provide an improved frame of the semi-integrated
type referred to above.
[0007] According to one aspect of the present invention there is provided a frame for.=supporting
implements on a vehicle with a chassis including a transversely extending axle housing,
said frame comprising a pair of rails arranged to extend longitudinally of the vehicle
in transversely spaced apart relation, first and second end portions on each rail,
a pair of tower structures arranged to be attached one to each rail to extend upwardly
from the rails at locations intermediate the end portions thereof, first interconnecting
means arranged to interconnect and maintain said first end portions of the rails in
a fixed transversely spaced relation, said second end portions being arranged to be
secured to second interconnecting means for interconnecting and maintaining said second
end portions in a fixed transversely spaced relation, means for connecting said first
end portions to the vehicle chassis stabilizing means arranged to extend between said
tower structures, said stabilizing means permitting constrained movement of the tower
structures whereby the rails can deflect under torsional loading, and attachment means
for attaching each rail to the axle housing intermediate said end portions.
[0008] The towers of the above frame are used to provide support for the lift arms and operating
cylinders of a front end loader and the second interconnecting means may comprise
a ballast weight if the vehicle is to be used as a loader only or part of a backhoe
structure if the vehicle is to include a backhoe.
[0009] A frame in accordance with the present invention is light in weight and capable of
flexing in bending and torsion in order to dissipate the loading imposed on the frame
by the implements without unduly loading the chassis to which the frame is secured.
[0010] For example, the stabilizing means between the towers ensures that when the towers
flex forces are transmitted between the towers by the stabilizing means to equalize
the loading on the towers and maintain a spaced relationship between the towers to
ensure that the loader does not bind due to tower misalignment.
[0011] The torsional characteristics of the frame can be varied by adjusting the flexibility
of the stabilizing means. The stabilising means may include a stabilizing plate arranged
to extend between the towers, said stabilizing plate having a hole therein generally
centrally located to relieve stress therein resulting from torsional loading of the
frame.
[0012] The stabilizing plate may have a generally Z shaped cross-section when cut by a vertical
plane extending generally longitudinally of the frame. The hole in the stabilizing
plate is preferably elongated in shape, the direction of elongation being transverse
relative to said frame.
[0013] The axle housing attachment means preferably includes flexible members which allow
relative twisting movement between said rails and axle housing during torsional loading
of the frame. This further improves the frame's ability to absorb torsional loading.
[0014] The second end portions of the rails are preferably provided with fastening means
for securing said second interconnecting means in position, said fastening means including
means for carrying shear loads. For example, said shear load carrying means may comprise
pins engaging said rails and second interconnecting means. These pins may be tapered
at one end to facilitate engagement of the rail ends with the second interconnecting
means.
[0015] To allow easy assembly of the frame and interchangeability of the various possible
forms of second interconnecting means the fastening means preferably includes bolts
for detachably securing the second interconnecting means to the rails.
[0016] The means for connecting the rails to the chassis may comprise two rail brackets,
one for attachment to each rail, and a chassis mounting plate for attachment between
the rail brackets.
[0017] Preferably the first interconnecting means comprises a steering axle support saddle
arranged to extend between said first end portions.
[0018] The rails of the frame are preferably structural channel mambers,. These rails may
be orientated with their bases extending substantially vertically and their side flanges
extending substantially horizontally, the steering axle support saddle being arranged
to be secured to the bottom side flanges of the rails.
[0019] A further important feature of the frame is that the rails diverge apart so that
the frame has a tapering configuration when viewed in plan, the frame having a greater
width at its second end portions than at its first end portions. This feature is of
importance in enhancing the stability of the frame when supporting a backhoe structure.
It removes the need to fabricate the rails with off-sets or bends in order to achieve
the necessary frame width at the rear of the frame.
[0020] The invention also provides a method of assembly a frame in accordance with the first
aspect of the invention on a vehicle having a chassis including a transversely extending
axle housing.
Brief Description of the Drawings
[0021] One embodiment of the present invention will now be described, by way of example
only, with reference to the accompanying drawings in which:-
Figure 1 is a perspective view of a vehicle equipped with an implement frame in accordance
with the present invention;
Figure 2 is an elevational view of just the frame of the vehicle in Figure 1;
Figure 3 is a plan view of the frame in Figure 2;
Figure 4 is a cross-sectional view along line 4-4 of Figure 3;
Figure 5 is a partial tross-sectional view along line 5-5 of Figure 2;
Figure 6 is a partial cross-sectional view along lines 6-6 of Figure 3;
Figure 7 is a cross-sectional view along lines 7-7 of Figure 6;
Figure 8 is a schematic view of the frame portion of Figure 6;
Figure 9 is a cross-sectional view along lines 9-9 of Figure 3, and
Figure 10 is a schematic view of a portion of the frame and vehicle of Figure 1.
Best Mode of Carrying Out Invention
[0022] Referring to Figure 1 of the drawings there is generally designated an industrial
tractor 10 having an implement frame 12 thereon in accordance with this invention.
The tractor 10 is equipped with front and rear wheels 14 and 16. The forward end of
the tractor 10 is equipped with a front end loader 18 and a backhoe 20 is located
at the rear of the tractor.
[0023] The backhoe 20 includes a bucket 22 pivotally connected to one end of a dipper stick
24 which in turn is pivotally connected at its upper end to a boom 26.
[0024] A bucket 22 is swingable through a vertical arc relative to the dipper stick 24.
A cylinder 28 is pivotally connected between the bucket 22 and dipper stick 24 for
this purpose. The dipper stick 24 is pivoted through a vertical arc relative to the
boom 26 by operation of a second cylinder 30 pivotally connected between the dipper
stick 24 and the boom 26. The boom 26 is also swingable through a vertical arc and
a third cylinder 32 is used to achieve this swing being pivotally connected between
the boom 26 and the backhoe 20.
[0025] The boom 26 is further swingable through a horizontal arc by virtue of a pair of
cylinders, one 34 of which is visible in Figure 1, located on either side of the boom
26 and pivotally connected between the boom 26 and the backhoe 20.
[0026] To accommodate the horizontal swing movement the boom 26 is pivotally mounted on
a swing casting 36 which in turn is pivotally mounted on part of a backhoe structure
40 for pivotting about a vertical axis 38. The backhoe structure 40 is equipped with
pivotally mounted stabilizers, one 42 of which is visible in Figure 1. These stabilizers
are each mounted for movement through a vertical arc by mens of their own stabilizer
cylinder 44 pivotally connected between the stabilizer 42 and the backhoe structure
40. In Figure 1 the stabilizer 42 is seen in the extended position whereby both sides
of the backhoe structure 40 are adequately supported by engagement of the stabilizers
42 with the ground.
[0027] At the front of the vehicle the loader 18 has a bucket 46 pivotally mounted at the
forward end of loader arms, one 48 of which can be seen in Figure 1, which are located
on either side of the tractor. The bucket 46 extends between the load arms 48 and
is pivoted thereon. Each loader arm 48 is equipped with pivotally mounted cylinder
50 which is pivotally connected to the bucket 46 to change the bucket position or
angle.
[0028] The elevation and lowering of the arms 48 is brought about through a second cylinder
52 for each load arm 48, the second cylinder 52 being connected at one end in a pivotal
fashion with the load arm 48 with which it is associated and at the other end to the
implement frame 12. The implement frame 12 is equipped with a subframe or tower 54
which provides a pivotal mounting for the rear end of the load arms 48.
[0029] The tractor 10 illustrated is a conventional agricultural type having an engine,
transmission housing and back- axle housing which are bolted together to form the
chassis, the sump of the engine being a structual component and constituting part
of the chassis. Power is delivered from the engine to a differential located in the
back axle housing via the transmission. The back axle housing provides support for
the rear wheels 16 and the front wheels 14 are mounted on the chassis via the implement
frame 12.
[0030] Figures 2 and 3-show the implement frame 12 is equipped with a front axle support
portion 56 which supports a conventional steering mechanism actuated by means of a
steering wheel as illustrated in Figure 1.
[0031] It will be appreciated that, with the backhoe stabilizers 42 and bucket 22 as well
as the front end loader 18 elevated relative to the ground, the tractor 10 in Figure
1 may be conveniently moved from one place to another under its own power as developed
by its motor. When the loader 18 is being used the forces directed towards the implement
frame 12 occur both from driving the vehicle 10 into a work pile with the bucket 46
orientated to fill the bucket 46 and by operation of the cylinders 50 and 52 on the
bucket 46 and lift arms 48 in curling the bucket 46 and elevating the arms 48 as the
work load is being engaged.
[0032] The operation of the backhoe 20 is usually acccmpan- ied by extension of the stabilizers
42 to engage the ground whereby the backhoe structure 40 and stabilizers 42 receive
the forces resulting from use of the backhoe 20 rather than the rear wheels 16 and
the vehicle chassis therefrom. The operation of the backhoe 20 may result in a wide
variety of stresses being applied to the tractor 10 but most particularly the implement
frame 12. Torsional stresses arise when the backhoe 20 is pivoted horizontally as
to dig on one side or the other of the tractor 10 rather than directly to the rear
thereof. The above stress phenomenon is not limited to the operation of the backhoe
20 but may also be present in the operation of the front end loader 18 when one side
of the bucket 46 encounters the load so as to eccentrically load the. bucket 46 and
implement frame 12.
[0033] Bending stress is also developed by the cantilever arrangement of the two implements
18 and 20 mounted on either extreme of the implement frame 12. In the past, where
loader frames have been supplemented with rear counterweight in order to counterbalance
the load on the front of a tractor, the bending stress transmitted to the tractor
chassis to which the loader frames were previously attached as load receiving members
resulted in localized bending stresses intermediate the length of the vehicle. Extreme
cases resulted in actually breaking the vehicle in two. The above problem could be
solved by using longitudinal frame members sufficiently strong so as not to bend and
thereby not stress the chassis of the tractor, but such members were found to be excessively
heavy. The addition of a backhoe in this operation imposed additional and extremely
serious problems of localized bending stress. For example, where both implements,
the front end loader and the backhoe, were used in conjunction to extract a mired
vehicle the resultant bending stresses were a complete reversal of those experienced
under normal operation conditions.
[0034] It is to be appreciated that the above operation is a desirable one for a vehicle
of an industrial nature which should be suitable for use on job sights even where
ground conditions are soft. Thus, the implement frame 12 should be suitable for enabling
the front and rear implements 18 and 20 to literally raise the tractor 10 off the
ground. While prior art structures had addressed themselves to the problem of bending
stresses which are accommodated in the implement frame, the same has not been true
for the torsional stresses which tend to twist the implement frame longitudinal members,
or rails, about their longitudinal axis. At best the prior art structures disclose
reinforcing the implement frame to thereby make the frame more rigid and prevent movement
of the implement frame. Thus, it can be seen that such stresses not being able to
be taken by deflection of the frame again are transmitted to the chassis of the vehicle.
As was found in the case of the bending stresses above, the transmission of forces
from the frame to the vehicle chassis is undesirable and therefore the frames had
to be increased in strength, and therefore weight, as was done previously for the
frames in bending. The point is again reached where the frames become excessively
heavy.
[0035] In the present structure the above is not the case and the advantageous operation
of the implement frame 12 being flexible in torsion as well as in bending is achieved
through employment of a semi-integrated frame construction of an arrangement which
will now be described with particular reference to Figures 2-9.
[0036] Referring to Figures 2 and 3 the primary longitudinal members or rails of the frame
12 illustrated are seen to be structural channel members 58 to which the tower assemblies
54 are welded. The towers contain bossed apertures for receiving pivots for the lift
arm cylinders 52 in the lower bosses 60, for the lift arms 48 themselves in the upper
left hand bosses 62, and for a member of the bucket linkage in the upper right hand
boss 64. The towers 54 are located intermediate the ends of the channels 58.
[0037] The front end of each channel 58 has an angle member 66 welded thereto and extending
there beyond with apertures 68
'therein for receiving the nose and grill of the tractor 10. The front axle support
saddle 56 constitutes a first interconnecting means extending between the rails 58.
The saddle 56 extends downwardly from the front of the channels 58 and includes front
and rear mounting plates 70, 72 having bosses 74 centrally mounted therein on the
longitudinal centre line of the frame 12 to provide a pivot axis A for the oscillation
of the front axle, a C-shaped stiffener 76 extends longitudinally between the front
and rear plates 70 and 72 with a gusset 78 extending transversely thereof acting as
a stiffener. A pair of flange plates 80 and 82 have a series of apertures 84 corressponding
to apertures 86 in the lower legs 88 of the frame channels 58 whereby bolts 90 may
be passed through to bolt the axle support saddle 56 to the channels 58.
[0038] Between the front axle saddle 56 and the towers 54 an engine support member in the
form of a L-shaped bracket 92 extends downwardly from each channel member 58 with
apertures 94 in the lower leg thereof for receiving means for fastening the bracket
92 to a mounting plate 96 on the engine of the tractor 10 as best seen in Figure 4.
The L-shaped brackets and plate 96 provide rail connecting means to the engine which
thus firmly attach the frame 12 to the tractor chassis while at the same time accommodating
some flexing of the rail about its longitudinal axis B and corner to corner deflection
of the frame 12 in the horizontal plane due to eccentric loads.
[0039] Between the tower 54 and the rear end of the frame 12, axle housing attachment means
are welded to the channels 58 taking the.form of L-shaped ears 98. The upstanding
leg 102 of each ear 98 has a recess 100 to increase the weld area of the member. Thus
each ear 98 is welded to the associated channel 58 around the entire periphery of
the recess 100 as well as along the two sides 104 forming the upper apex of the leg
102. The welds along the sides 104 terminate a point just short of the bottom of the
channel 58 to leave a portion at the bottom of the channel is free of weld. The ears
98 each have a horizontal leg 106 with apertures 108 therein for receiving fastening
means for fixedly attaching the leg 106 to the axle housing 110 of the tractor 10.
The legs 106 together with the unwelded portion of the upper legs 102 provide for
flexibility between the axle housing 110 and the channel members 58. Thus, again the
channel members 58 may flex about their longitudinal axes B under torsional loading.
[0040] At the rear of each channel 58 a face plate 112 is welded to the butt end thereof.
Each plate 112 has a pin 114 welded in an aperture therein with the end of the pin
114 extending from the plate 112 and having a taper 116 thereon for guiding the pin
114 into a countereieght 118 attached thereto.
[0041] The counterweight 118, illustrated in Figures 2 and 3, is an alternate to the embodiment
in Figure 1 replacing the centre mount backhoe 20 illustrated in Figure 1. As a further
alternative, a side shift backhoe structure could also be -aounted on the present
frame. All of these alternatives provide second interconnecting means for interconnecting
the rear ends of the rails.
[0042] All the above assemblies and their loads are supported in shear by the pins 114 in
the face plates 112 and are attached by four bolts 116 passing through apertures 118
in the face plates 112 as best illustrated in Figure 5. The counterweight 118 at the
rear of the vehicle and the front axle support saddle 56 at the front of the frame
12 form a box structure wherein the channel 58 between these two points is able to
flex under torsional stress about its longitudinal axis B and able to flex under bending
stress between the rear axle housing 110 connection and the rail connection to the
engine in the manner ' of a simply supported beam supported at the above two connections.
[0043] The box structure formed by the rails 58, the axle support 56 and the counterweight
118 is clearly shown in Figure 3.
[0044] In addition each tower structure 54 as can be seen from Figures 3 and 6 consists
of an inner upwardly extending plate 120 welded to the outside o
'f the associate rail 58. An outer plate 112 of the same configuration as the inner
plate 120 extends over the face o,f the inner plate 120 being terminated just short
of the bottom thereof by bending the plate 122 inwardly and extending it to the inner
plate 122 to which it is welded. A horizontal gusset plate 124 extends between the
inner and outer plates 120 and 122 to maintain them spaced apart and a back plate
126 extending over the total height of the tower 54 completes the assembly. The bosses
62 and 60 for the lift arm 48 and lift arm cylinder 52 are provided in both the inner
and outer plates 120 and 122 with the bosses 60 for the lift arm cylinders 52 passing
through both the inner plate 120 and the web of the channel 58. The bosses 64 for
the lift arm link 63 on the other hand are continuous extending between the inner
and outer plates 120 and 122.
[0045] Figure 3 further illustrates a Z-shaped plate 128 which provides a stabilizing means
between the towers 54. In the illustrated embodiment the plate 128 has a stress relief
hole 130 therein as best illustrated in Figures 6 and 7. Although the plate 128 stabilizes
the towers 54 it allows enough freedom for flexure of the channels 58 on which the
towers 54 are mounted under torsional stress, see Figure 3. The plate 128 has opposite
hand end plates 132 welded to each end thereof with apertures 134 therein for receiving
bolts for bolting the end plates 132 and thereby the plate 128 to the towers 54. In
Figures 6 and 7, the stress relief hole 130 in the plate 128 can be seen to be elongated
with the upper and lower sides 136 and 138, forming its border, being longer than
the sides 140 and 142 which complete the hole's border. Thus, a full cross-section
of plate 128 exists adjacent the end plates 132 to act as a reinforcing stiffener
because the stabilizing means is symmetrical about line C. At the same time, the configuration
of the hole 130 provides a lesser cross section of material at the top and bottom
of the plate 128 where the line C intersects it to permit flexing of these portions
when the channels 58 flex in torsion due to transverse deflection of the towers 54
under eccentric loading of the frame 12. The lips 144 and 146 in Figure 7 together
with the above lesser cross section of the plate 128 form angle reinforcements uniform
in cross section between the towers 54 to transfer loads therebetween and maintain
the spacing between the towers 54 necessary for the desired operation of the loader
18 via the arms 48 and linkage 63 attached to the towers 54. Thus, the plate acts
as an equalizer for forces on the towers 54.
[0046] In Figure 8 a schematic example is given of one type of tower deflection which may
occur being exaggerated for purposes of illustration. Ncte the twisting of the channels
58 under the loading created by the force F in the direction indicated by the arrow.
The force is a component resulting from eccentric loading on the frame 12 from, for
example, use of one corner of the loader bucket 46 as described above. Another example
would be deflection of the towers 54 relative to each other in the longitudinal direction
of the channels 58 causing the plate 128 to twist. In this instance, the lesser cross
section and lips 144 and 146 forming the angle reinforcements would be able to twist
in a manner similar to that illustrated in Figure 8 for the channels 58. In each case
the ability of a structural member to deflect prevents excessive stress on the plate
128 to tower 54 connection to avoid tearing the structure apart.
[0047] In Figures 2 and 3 at the rear of the frame 12 the face plate 112 can be seen to
be reinforced by inner and outer gusset plates 148 and 150 as well as a bottom gusset
plate 152 as further illustrated in Figure 9. The bottom gusset plate 152 extends
over the outer gusset plate 150 and to both the channel 58 and the face plate 112.
The outer gusset plate 150 has three slotted apertures 154 for receiving alignment
pins and the'inner gusset plate 148 can be seen to have a bend in it to permit the
plate to extend from the outer portion of the channel 58 upper leg to the inner portion
of its lower leg. In Figure 2 the inner gusset plate 148 can be seen to have two legs
156 and 158 which extend towards the front of the frame 12 and are tapered in the
direction of their extension. A gusseted angle member in Figure 9 is attached to the
inner gusset plate 148 to provide a bracket 160 for supporting tractor components.
[0048] In Figure 10 a schematic example is given of-one type of channel deflection which
occurs under torsional loading of the frame 12, being exaggerated for purposes of
illustration. It can be seen that the twisting of the channels 58 causes deflection
of the L-shaped ears 98 to prevent excessive stresses from arising and/or excessive
loading of the axle housing 110.
[0049] In Figure 3 the channels 58 can be seen-to diverge from front (left) to rear (right)
to accommodate the gauge of the front wheels 14 while providing as wide, and therefore.
as stable, a connection as possible to receive the loading from the backhoe 20. The
frame thus has a tapering configuration when viewed in plan. The rear ends of the
channels 58 are fixed in spaced apart relation in a plane transverse to the longitudinal
axis D of the tractor 10 and its frame 12 by means connecting the ends of the channels
58, such as the counterweight 118 or backhoe structure 40, to maintain the channels
58 in an outwardly diverging unbroken line from each other.
[0050] Previously, the frames for supporting implements have either not taken advantage
of a widened backhoe connection by maintaining the gauge of the front wheels, or where
the gauge of the frame was changed the frame was fabricated with accommodating offsets
or bent to achieve the same result. In both above cases the bends or fabricated joints
presented points for high stresses under loading and if torsional stress were allowed
to twist the frame members as in the present application there would be likelihood
of failure of the frame at these points.
[0051] The frame 12 is assembled as follows. First a rail 58 and a tower 54 are secured
in a jig to align these components in their correct relative positions, the bosses
60-64 being used for alignment purposes. The tower and rail are then welded together
to form a first subassembly which also includes the bracket 92, 160, member 60, plate
112, pin 114 and ear 98. This process is then repeated to produce a second subassembly
consisting of the rail and tower for the other side of the frame 12.
[0052] These two subassemblies are then moved to a vehicle chassis and are loosely bolted
to the back axle 110 using bolts extending through apertures 108 in the ears 98.
[0053] The front ends of the rails 58 are then secured in a jig at the correct spacing and
the rear ends of the rails are then canted outwardly, that is moved away from the
longitudinal axis D of the frame to give the desired tapering frame shape. The rear
ends of the rails are then held in their correct relative positions by a further jig
which extends between the rear ends of the rails and uses the pins 114 for location.
[0054] The plate 128 is then secured between the towers 54 and bolted up tight. The mounting
plate 96 and axle saddle 56 are then secured firmly between the rails and the bolts
securing the rails to the back axle are then tightened. The jigs extending between
the front and rear ends of the rails can now be removed and the frame moved to the
next assembly point on the line.
[0055] The above frame 12 results in a lightweight rugged semi-integrated structure for
carrying implements on a vehicle which can be stressed in both bending and torsion
without adverse effect on the chassis of the vehicle to which the frame 12 is attached
while at the same time providing sufficient connection to the chassis of the vehicle
to obtain all the advantages of an integrated frame. Thus, the frame 12 optimizes
the advantages of the lightweight of the attachable type loader frames while providing
the strength and ruggedness approaching that of an integrated frame.
1. A frame for supporting implements on a vehicle with a chassis including a transversely
extending axle housing said frame being characterised by comprising a pair of rails
(58) arranged to extend longitudinally of the vehicle (10) in transversely spaced
apart relation, first and second end portions on each rail, a pair of tower structures
(54) arranged to be attached one to each rail to extend upwardly from the rails at
locations intermediate the end portions thereof, first interconnecting means (56)
arranged to interconnect and maintain said first end portions of the rails in a fixed
transversely spaced apart relation, said second end portions being arranged to be
secured to second interconnecting means (118;40) for interconnecting and maintaining
said second end portions in a fixed transversely spaced relation, means (92,96) for
connecting said first end portions to the vehicle chassis, stabilizing means (128)
arranged to extend between said tower structures, said stabilizing means permitting
constrained movement of the tower structures whereby the rails can deflect under torsional
loading, and attachment means (98.) for attaching each rail to the axle housing (110)
intermediate said end portions.
2. A frame according to claim 1 characterised in that said stabilizing means includes
a stabilizing plate (128) arranged to extend between said.towers (54), said stabilizing
plate having a hole (130) therein generally centrally located to relieve stress therein
resulting from torsional loading of the frame (12).
3. A frame according to claim 2 characterised in that said stabilizing plate (128)
has a generally Z-shaped cross section when cut by a vertical plane extending generally
longitudinally of the frame (12).
4. A frame according to claim 2 or claim 3 characterized in that the hole (130) has
an elongated shape, the direction of said elongation being transverse relative to
said frame (12).
5. A.frame according to any one of claims 2 to 4 characterized in that said stabilizing
means further includes a pair of flange plates (132) abutting the ends of said stabilizing
plate (128), said flange plates being fixedly attached to said plate and arranged
to be connected (135) to said towers (54).
6. A frame according to claim 5 characterised in that said flange plates (132) are
arranged to be connected to said towers by bolts (135).
7. A frame according to any one of claims 1 to 6 characterised in that said axle housing
attachment means includes flexible members (98) which allow relative twisting movement
between said rails (58) and axle housing (110) during torsional loading of the frame
(12).
8. A frame according to claim 7 characterised in that said flexible members (98) are
L-shaped in form with one leg (102) thereof connected to said rails (58) and the other
leg (106) arranged to be connected to said axle housing (110).
9. A frame according to claim 8 characterised in that said other leg (106) includes
apertures (108) therein and said axle housing attachment means includes bolts for
passing through the apertures in said other leg to affix said other leg to said axle
housing (110).
10. A frame according to claim 8 or claim 9 characterised in that the free edges (104)
of said one leg (102) of each flexible member (98) are welded to the associated rail
(58).
11. A frame according to any one of claims 1 to 10 characterised in that the second
end portions of the rails (58) are provided with fastening means (112,114) for securing
said second interconnecting means (118;40) in position, said fastening means including
means (114) for carrying shear loads.
12. A frame according to claim 11 characterised in that said shear load carrying means
comprise pins (114) engaging said rails and said second interconnecting means (118:40).
13. A frame according to claim 12 characterised in that said pins (114) are tapered
(116) at one end thereof to facilitate engagement of said rail ends with said second
interconnecting means (118;40).
14. A frame according to any one of claims 1 to 13 characterised in that said second
interconnecting means is part of a backhoe structure (40).
15. A frame according to any one of claims 1 to 13 characterised in that said second
interconnecting means is a counterweight (118).
16. A frame according to claim 14 or claim 15 characterised in that said fastening
means includes bolts (119) for detachably securing said second interconnecting means
(118;40) to said rails (58).
17. A frame according to any one of claims 1 to 16 characterised in that said means
for connecting the rails to the chassis comprises two rail brackets (92), one for
attachment to each rail, and a chassis mounting plate (96) for attachment between
the rail brackets.
18. A frame according to any one of claims 1 to 17 characterised in that the first
interconnecting means comprises a steering axle support saddle (56) arranged to extend
between said first end portions.
19. A frame according to any one of claims 1 to 18 characterised in that said rails
(58) are structural channel members.
20. A frame according to claim 18 and claim 19 characterised in that the channel members
(58) are orientated with their bases extending substantially vertically and their
side flanges extending substantially horizontally, the steering axle support saddle
(56) being arranged to be secured to the bottom side flange of the channel members.
21. A frame according to any one of claims 1 to 20 characterised in that the rails
(58) diverge apart so that the frame has a tapering configuration when viewed in plan,
the frame having a greater width at its second end portions than at its first end
portions.
22. A method of assembling a frame according to claim 1 on a vehicle with a chassis
including a transversely extending axle housing, being characterised by including
the steps of:-
forming a first subassembly by securing a rail (58) and a tower (54) in an alignment
jig and welding the tower to the rail;
forming a second similar subassembly by repeating the above step with a further rail
and tower;
transporting the two subassemblies to the chassis; loosely fastening each subassembly
to the chassis; fixing a jig between the first or second end portions of the rails;
canting the rails so that the frame has a longitudinally tapering configuration when
viewed in plan;
fixing a further jig between the other end portions of the rails;
securing the stabilizing means (128) between the towers;
fastening the first (56) and second (118;40) interconnecting means between the end
portions of the rails, and tightening the fastening of the rails to the chassis.
23. A method according to claim 22 characterised in that in the previously referred
to step of loosely fastening the rails to the chassis the rails (58) are in fact loosely
fastened to the back axle housing (11o).