U.S. patent application number 13/497109 was filed with the patent office on 2012-07-12 for extendible dipper with extruded portion for a backhoe arm.
This patent application is currently assigned to Volvo Compact Equipment SAS. Invention is credited to Christophe Cartry, Jimmy Reverdy, Philippe Valentini.
Application Number | 20120177471 13/497109 |
Document ID | / |
Family ID | 41682795 |
Filed Date | 2012-07-12 |
United States Patent
Application |
20120177471 |
Kind Code |
A1 |
Valentini; Philippe ; et
al. |
July 12, 2012 |
EXTENDIBLE DIPPER WITH EXTRUDED PORTION FOR A BACKHOE ARM
Abstract
The invention relates to an extendible dipper assembly (32) for
a backhoe arm for a construction equipment machine, said arm
comprising a boom to be attached to the machine, and an extendible
dipper assembly (32) articulated at the free end of the boom (30)
for holding a working 38 tool, said extendible dipper assembly (32)
comprising a proximal part (34) articulated to the boom (30) and a
distal part (36) which is slidingly connected to the proximal part
so as to form a length-adjustable dipper assembly, characterized in
that at least one of the dipper parts (34, 36) comprises a
rectilinear profile made by extrusion of metal, said profile having
a closed cross-section around at least one inner cavity.
Inventors: |
Valentini; Philippe; (St.
Sylvestre, FR) ; Cartry; Christophe; (Belley, FR)
; Reverdy; Jimmy; (Ambleon, FR) |
Assignee: |
Volvo Compact Equipment SAS
Belley
FR
|
Family ID: |
41682795 |
Appl. No.: |
13/497109 |
Filed: |
September 21, 2009 |
PCT Filed: |
September 21, 2009 |
PCT NO: |
PCT/IB2009/007276 |
371 Date: |
March 20, 2012 |
Current U.S.
Class: |
414/722 |
Current CPC
Class: |
E02F 3/306 20130101 |
Class at
Publication: |
414/722 |
International
Class: |
E02F 3/39 20060101
E02F003/39; E02F 3/30 20060101 E02F003/30 |
Claims
1. Extendible dipper assembly for a backhoe arm for a construction
equipment machine, the arm comprising a boom to be attached to the
machine, and an extendible dipper assembly articulated at the free
end of the boom for holding a working tool, the extendible dipper
assembly comprising a proximal pact articulated to the boom and a
distal part which is slidingly connected to the proximal part so as
to form a length-adjustable dipper assembly, wherein at least one
of the dipper parts comprises a rectilinear profile made by
extrusion of metal, the profile having a closed cross-section
around at least one inner cavity.
2. Extendible dipper assembly according to claim 1, wherein the
rectilinear profile comprises at least one rectilinear protrusion
which extends outwardly in cross section and which forms a rail for
slidingly connecting the proximal part to the distal part, the
rectilinear protrusion being formed by extrusion together with the
rectilinear profile.
3. Extendible dipper assembly according to claim 2, wherein the
rectilinear protrusion comprises at least one guiding surface which
cooperates with a slide or a roller of the other part of the dipper
for slidingly connecting the proximal part to the distal part, the
guiding surface being directly obtained through the extrusion
process.
4. Extendible dipper assembly according to claim 2, wherein the
rectilinear profile comprises two rectilinear protrusions which are
located un-symmetrically with respect to a geometric axis of the
cavity, and in that the rectilinear profile comprises at least one
wall portion which is located substantially opposite the
protrusions with respect to the cavity axis, the opposite wall
portion having an increased thickness in comparison to at least one
other wall portion of the profile.
5. Extendible dipper assembly according to claim 4, wherein the
rectilinear profile is substantially rectangular with two lateral
wall portions extending along its longest dimension, a bottom wall
portion and a top wall portion, in that the protrusions are located
near the bottom wall portion, and in that the top wall portion has
an increased thickness in comparison to the thickness of the bottom
wall portion.
6. Extendible dipper assembly according to claim 1, wherein the
rectilinear profile is made of steel having an elastic limit of at
least 240 MPa.
7. Extendible dipper assembly according to claim 1, wherein the
rectilinear profile is made of steel having an elastic limit of at
least 360 MPa.
8. Extendible dipper assembly according to claim 1, wherein the
rectilinear profile is made of aluminium or of an aluminium
alloy.
9. Extendible dipper assembly according to claim 1, wherein the
rectilinear profile is devoid of welding around its
cross-section.
10. Extendible dipper assembly according to claim 1, wherein the
distal part of the dipper comprises a rectilinear profile made by
extrusion of metal, the profile having a closed cross-section
around at least one inner cavity.
Description
BACKGROUND AND SUMMARY
[0001] The invention relates to the field of construction equipment
machines having a backhoe arm where a part of the arm is
extendible.
[0002] Many construction equipment machines are equipped with a
backhoe, that is a piece of equipment where a bucket is mounted at
the end of an arm, the arm being itself mounted on a chassis of
machine. The arm usually comprises at least a boom, which is
articulated to the chassis through at least a horizontal axis, and
very often also around a vertical axis, and a dipper which is
articulated at the free end of the boom around another horizontal
axis. The dipper may also be articulated with respect to the boom
around a vertical axis. Each of these movements is controlled by a
power cylinder, usually a hydraulic cylinder, respectively a boom
cylinder for controlling the movement of the boom relative to the
chassis and a dipper cylinder for controlling the movement of the
dipper relative to the boom. The bucket is articulated to the
dipper around another horizontal axis and is controlled by another
cylinder. In a backhoe, the bucket and the arm can be controlled to
pull back material towards the chassis of the machine.
[0003] In some cases, the dipper part of the arm is extendible,
that is it comprises a proximal part articulated to the boom and a
distal part which is slidingly connected to the proximal part so as
to form a length-adjustable dipper assembly. A cylinder is in most
cases provided for adjusting the relative position of the two parts
of the dipper.
[0004] In most cases, the dipper is made of an elongated hollow box
section made of metal. A conventional way of making a dipper is to
weld together four elongated plates of metal at or near their
longitudinal edges in order to form the box section.
[0005] In the case of an extendible dipper, there needs to be
provided a slide mechanism connecting the two parts of the dipper
in a way that the two parts may slide relative one the other along
a longitudinal direction but that they are otherwise rigidly
connected along all other directions. Such slide mechanism is known
where one part is equipped with two parallel rails, and where the
other part is equipped with a set of slides which slide on at least
two opposite surfaces of each of the rails to achieve the desired
sliding junction of the two parts. In some cases, the rails may be
welded on the corresponding part. It is also known to have one part
of the dipper which comprises an extruded U shaped rectilinear
portion to which is welded another U shaped portion. The two U
shaped portions are mounted upside down. The extruded welded
portion may comprise rails which are formed by extrusion together
with the rectilinear U shaped extruded portion. This long known
fabrication technique has proven successful but needs very careful
welding operations. Indeed, it is well known that welding
operations, which involve localized heating and subsequent cooling
of the portions to be assembled, tend to generated internal
stresses in the final object which cause deformations of said
object. Such deformations are unacceptable when it is required that
the object is to be joined to another object through a very precise
sliding connection. Therefore, such cautious welding operations
which are necessitated with the known fabricating techniques of
extendible dipper arms make them expensive.
[0006] It is desirable to provide a new design of an extendible
dipper assembly which would allow using easier and lower cost
manufacturing processes.
[0007] It is proposed an extendible dipper assembly for a backhoe
arm for a construction equipment machine, said arm comprising a
boom to be attached to the machine, and an extendible dipper
assembly articulated at the free end of the boom for holding a
working tool, said extendible dipper assembly comprising a proximal
part articulated to the boom and a distal part which is slidingly
connected to the proximal part so as to form a length-adjustable
dipper assembly, characterized in that at least one of the dipper
parts comprises, a rectilinear profile made by extrusion of metal,
said profile having a closed cross-section around at least one
inner cavity.
DESCRIPTION OF FIGURES
[0008] FIG. 1 is a schematic side view of a backhoe loader equipped
with an extendible dipper.
[0009] FIG. 2 is a schematic perspective view of the distal and
proximal parts of a length-adjustable dipper assembly.
[0010] FIG. 3 is a schematic transversal section of a
length-adjustable dipper assembly, showing the sliding connection
of the proximal and distal parts of the dipper assembly.
[0011] FIG. 4 is a schematic perspective view of an extruded linear
profile from which a dipper part according to the invention can be
made.
[0012] FIG. 5 is a cross section of the extruded linear profile
shown on FIG. 4.
DETAILED DESCRIPTION
[0013] On FIG. 1 is shown a construction equipment machine 10 of
the so-called backhoe-loader type. Such machine comprises a chassis
12 mounted on four wheels and a cabin 14 mounted on the chassis for
receiving an operator of the machine. In front of the cabin 14, a
bonnet 16 receives the machine's main engine. Such a machine
therefore exhibits the main looks of an agricultural tractor. It
derives its name from the fact that it carries two main pieces of
equipment, namely a loader equipment 18 at the front, and a backhoe
equipment 20 at the rear. The loader equipment 18 comprises
essentially two loader arms 22 which are articulated on the chassis
around a horizontal axis Al near the rear end of the bonnet 16 and
which extend longitudinally towards the front on both sides of the
bonnet 16. At the free ends of the loader arms, in front of the
bonnet 16, a loader bucket 24 having a generally forward facing
cavity is articulated around a horizontal axis A2.
[0014] The backhoe equipment 20 comprises a backhoe arm 26 which is
articulated on the chassis 12 and which carries at its free end a
working tool such as an excavator bucket 28. In the shown
embodiment, the backhoe arm 26 comprises a boom 30 and an
extendible dipper assembly 32. The boom 30 is articulated to the
chassis around a horizontal axis A3 and around a vertical axis A4,
each rotation movement being controlled by at least one actuator,
usually a hydraulic cylinder. As better seen on FIG. 2, the dipper
assembly 32 comprises two main parts, namely a proximal part 34
which is articulated at one end around a horizontal axis A5 at the
free end of the boom 30, and a distal part 36 which is slidingly
connected to the proximal part 34 so as to extend along a
lengthwise axis X-X beyond the free end of the proximal part 34.
The two parts 34, 36 are connected by an actuator, not shown on the
drawings but usually embodied as a hydraulic cylinder, to expand or
retract the distal part with respect to the proximal part, thereby
adjusting the length of the dipper assembly 32. The excavator
bucket 28 is articulated at the free end 40 of the distal part 34
around a horizontal axis A6.
[0015] The proximal part 34 of the dipper assembly 32 is for
example a fabricated steel sheet structure which extends along the
lengthwise axis X-X of the dipper assembly and which exhibits
approximately the shape of a U when viewed in cross section, the U
shape enclosing partially an inner space 38 which is open towards
its top, at least along a substantial portion of the proximal part
34. As can be seen on FIG. 2, the distal part 36 is at least
partially received within the inner space 38 of the proximal part
34, both lengthwise and in cross section. In any case, at least in
an extended configuration, the free end 40 of the distal part 36
extends lengthwise beyond the free end 42 of the proximal part 34,
outside of inner space 38.
[0016] As can be seen on FIG. 3, the proximal part of the dipper is
fabricated with metal plates which are welded together, mainly two
lateral plates 44 which extend parallel one to the other, and a
cross plate 46 which extends between the two lateral plates 44. The
proximal part also comprises bushes and reinforcements which are
mainly made as welded add-on parts.
[0017] A backhoe loader such as the one described above is well
known to the skilled man in the art and is for example commercially
available as "Volvo BL 71".
[0018] In the example shown on the figures, the distal part 36 of
the dipper assembly comprises a rectilinear profile 48 made by
extrusion of metal, said profile having a closed cross-section
around at least one inner cavity 50. The rectilinear profile 48 is
best shown on FIGS. 4 and 5 where it is represented just after its
fabrication by the extrusion process. The rectilinear profile
extends along the lengthwise axis X-X of the dipper assembly, and
it is therefore possible to define the axis X-X as being the
extrusion axis. The inner cavity 50 is closed when viewed in cross
section along a plane perpendicular to axis X-X, as represented.
Said otherwise, the rectilinear portion exhibits a continuous wall
portion which extends around axis X-X. Therefore, the rectilinear
profile is inherently very rigid, and inherently resists to
flexions around any axis perpendicular to the lengthwise axis X-X,
but also resists to torsion around said lengthwise axis X-X.
[0019] In the example shown, the rectilinear profile 48 encloses
only one inner cavity 50 which is substantially rectangular in
cross section, with rounded angles. Indeed, the rectilinear profile
comprises a continuous wall made of mainly four wall portions, two
lateral wall portions 52 and two cross wall portions which can be
called top wall portion 54 and bottom wall portion 56. Top and
bottom here simply refer to the drawings and are not to be
construed as limiting the scope of the invention. The lateral wall
54 portions are parallel one to the other and the cross wall
portions 56 are also parallel one to the other, but perpendicular
to the lateral wall portions. Each lateral wall portion 54 is
connected to the two cross wall portions 56 by a rounded wall
portion, and vice-versa.
[0020] As represented on the figures, the rectilinear profile
comprises two rectilinear protrusions 58 which extend each
outwardly in cross section from the lateral wall portions 52 and
which each form a rail for slidingly connecting the proximal part
34 to the distal part 36. In the example shown, the protrusions are
located near the bottom wall portion 56. In the particular example
shown, they exhibit a triangular cross section with one side being
simply adjacent to the corresponding lateral wall portion, an upper
side 60 perpendicular to the lateral wall portion and a lower side
62 which is slanted at approximately 45 degrees and which merges
with the bottom wall portion 56. As can be seen on FIG. 2, the
upper and lower side of the protrusions 58 form guiding surfaces
which are deemed to cooperate with slides or rollers arranged on
the proximal part so as define a sliding connection between the two
parts. Both rectilinear protrusions 58 are preferably formed by
extrusion together with the rectilinear profile. This of course
eases considerably the assembly and the operation of the dipper
inasmuch as, being obtained through the extrusion process, the
protrusions have a well defined geometry and have a well defined
location with respect one to the other and with respect to the
other wall portions of the rectilinear profile. Thanks to the
intrinsic qualities of the extrusion process, the upper and lower
surfaces of the protrusions need not necessarily be further
machined after extrusion to exhibit the dimensions and surface
geometries required for them to function as guiding surfaces in the
sliding connection between the two parts of the dipper.
[0021] In the example shown, the two rectilinear protrusions 58 are
located un-symmetrically with respect to a geometric axis of the
cavity. In the example shown, the cavity 52 is: symmetrical around
a central axis which can be considered to correspond to the
lengthwise axis X-X mentioned above. Rather than being at the level
of the axis X-X, the protrusions extend near the bottom wall
56.
[0022] According to an advantageous feature, the top wall portion
54 has an increased thickness in comparison to the thickness of the
bottom wall portion 56. The thickness of the top wall portion is
preferably at least 25% superior to that of the bottom wall
portion, but can be more than 50% superior. As a matter of fact,
the bottom wall portion 56 is here represented has having
approximately the same thickness as the two lateral wall portions
52 but it could in fact exhibit a lower thickness than the two
lateral portions. Of course, the rectilinear profile 48 is designed
so that it resists to all the stresses it will meet in operation,
but the advantage of providing an excess thickness in the upper
wall portion 54, i.e. the wall portion which is on the opposite to
the protrusions 58 with respect to the cavity axis X-X, is that the
centre of gravity of the profile, when considered in cross section,
is close to the axis of symmetry of the cavity, despite the
un-symmetrical locations of the protrusions 58. This allows an
easier production of the profile 48 with the protrusions 58 by the
known extrusion techniques.
[0023] Thanks to this feature, the rectilinear profile 48 can be
made of steel having an elastic limit of at least 240 MPa, or even
of at least 360 MPa. Alternatively, the rectilinear profile 58
could be made of aluminium or of an aluminium alloy.
[0024] Thanks to the proposed design, the rectilinear profile 48 is
devoid of welding around its cross-section. This avoids any
deformation which may be caused by a welding operation.
[0025] Of course, the rectilinear profile 48 is a base element of
the distal part 32, but the rectilinear profile may be transformed
to form the distal part, and the distal part may also comprise
other components. At a minimum, the rectilinear profile will be cut
at the right length for forming the distal part. Holes may be
drilled in the profile, for example at axis A6 for receiving an
articulation for the working tool. For example, such articulation
holes may reinforced by the provision of bushings which may be
welded on the rectilinear profile. Also, brackets may be fixed on
the rectilinear profile, by welding or by other attaching means,
for example for the connection of the power cylinders which control
the extension of the dipper assembly and/or control the movement of
the working tool.
[0026] In the example shown and described above, it is the distal,
part 36 of the dipper assembly 32 which comprises a rectilinear
profile 48 made by extrusion of metal according to the invention,
while the proximal part is of a more conventional design.
Nevertheless, The proximal part 34 of the dipper assembly 32 could
also or alternatively comprise a rectilinear profile made by
extrusion of metal according to the invention.
[0027] It is to be mentioned that, within the scope of the
invention, the cross-section of the rectilinear profile and of its
inner cavity could be other than rectangular, and could be for
example in the shape of a trapeze, circle, oval, or even exhibit a
more complex design, such as the shape of an X. The cross-section
could also be non-symmetric, not withstanding the further
un-symmetrical location of the protrusions. Also, the rectilinear
profile could comprise more than one cavity defined within the
closed cross section. For example the inner cavity could exhibit
several partitions formed by a wall portion obtained directly
during the extrusion process.
[0028] All in all, the use, of an extruded closed section
rectilinear profile allows to produce more easily, more cheaply and
more quickly a dipper assembly which exhibits superior performance,
especially due to the fact that the extrusion process minimizes the
residual constraints which are inherent to the conventional
fabrication process based on welded plates.
[0029] The invention has been described in the context of a backhoe
arm to be mounted on a backhoe-loader, but it would obviously be
applicable in any type of backhoe arm, for example for use on an
excavator.
* * * * *