Note: Descriptions are shown in the official language in which they were submitted.
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PALLET FORK IMPLEMENT FOR WORK MACHINE
FIELD
[0001] The present discussion relates to a work implement for a power machine
such as
an excavator. In particular, the present discussion relates to pallet fork
implements or
attachments which can be mounted or engaged on a blade of a power machine and
which can
be stowed in a carrier system attached to or proximate an undercarriage of the
power
machine.
BACKGROUND
[0002] Forklifts are commonly used to lift pallets and other loads. Forklifts
include pallet
forks that engage a pallet or other load to be lifted, allowing a lift
mechanism of the fork lift
to lift the load in a stabilized manner. It is frequently too costly and
otherwise inconvenient to
have a forklift available at a worksite, particularly since the need for the
forklift may be
temporary, short term, and/or otherwise infrequent.
[0003] To reduce the need for a separate forklift vehicle at a worksite,
pallet forks have
been fixedly attached to other implements or attachments of power machines.
For example,
pallet forks have been attached to buckets for this purpose. To accomplish the
attachment of
pallet forks to a bucket or other type of attachments, some sort of mounting
structure on the
host attachment is used to engage with the pallet forks to fixedly attach the
forks to the host
attachment. This type of mounting structure adds cost and complexity to the
power machine,
to the host attachment, and/or to the pallet fork implement.
[0004] In at least some instances, pallet fork assemblies that are designed to
engage
attachments of a power machine have required adjustability to work with a
variety of host
attachments. They have also required fastening mechanisms that are used to
secure the pallet
fork assemblies to the implement. The need for adjustable pallet fork
implements and/or the
need for the pallet fork implements to include fastening mechanisms can
increase
manufacturing costs, manufacturing complexity, installation time, etc.
[0005] The discussion above is merely provided for general background
information and
is not intended to be used as an aid in determining the scope of the claimed
subject matter.
SUMMARY
[0006] A pallet fork implement is configured to be mounted on a blade of a
power
machine. The pallet fork attachment includes an engagement portion for
engaging the blade
of the power machine, and a tine portion for performing a work function. The
tine portion is
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configured to extend generally forward of the blade when the engagement
portion is engaged
with the blade. The engagement portion of the pallet fork implement is a
unitary assembly.
[0007] This Summary and the Abstract are provided to introduce a selection of
concepts
in a simplified form that are further described below in the Detailed
Description. This
Summary and the Abstract are not intended to identify key features or
essential features of
the claimed subject matter, nor is it intended to be used as an aid in
determining the scope of
the claimed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 is a perspective view of a power machine having a host blade
attachment
or implement that receives a pallet fork implement in accordance with
disclosed
embodiments.
[0009] Figure IA is a perspective view of the power machine of figure 1, with
pallet fork
implements mounted on the host blade attachment.
[0010] Figure 2 is a perspective view of portions of an undercarriage of a
power machine,
such as the one shown in figure 1, illustrating pallet fork implements in both
mounted and
stowed positions.
[0011] Figures 3A and 3B illustrate top and side views of an embodiment of the
pallet
fork implement.
[0012] Figure 4 is a rear view illustration of a portion of the power machine
of figure 1,
with a pair of pallet fork implements in a stowed position.
[0013] Figure 5 is a diagrammatic side view of the pallet fork implement in
position to be
accepted onto a host blade attachment shown in cross section, illustrating
features of the
pallet fork attachment that aid in installation and use.
[0014] Figure 6 is a diagrammatic side view of the pallet fork attachment
accepted onto a
host blade attachment shown in cross-section, illustrating features of the
pallet fork
attachment that aid in installation and use.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0015] Figure 1 illustrates a perspective view of a power machine 100. For
illustrative
purposes, power machine 100 is shown to be a self-propelled power excavator
that has a
chassis or undercarriage 102 and an upper rotatable frame 104. However, power
machine 100
need not be an excavator, but can instead be other types of power machine.
Undercarriage
102 includes a lower frame 106 and a pair of support surface engaging track
assemblies 108
that are attached to the lower frame 106 and driven with a suitable drive
arrangement, such as
with hydraulic drive motors. Upper rotatable frame 104 supports a pivotally
mounted two-
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section boom-arm structure 110, which illustratively includes both a boom
section 111 and an
arm section 113, capable of having an implement 112 (a bucket is shown in
figure 1) attached
to an outer end thereof. The sections of boom-arm structure 110 are
illustratively operated
with actuators shown generally at 114 for moving the boom and arm sections
about
horizontal pivots. Implement 112 is also operated with an actuator 116 to
allow for pivotable
movement of the implement 112 with respect to the arm section 113. Upper
rotatable frame
104 also includes an operator compartment 118 and a housing 120 for an engine
for
providing power to the suitable drive arrangement that drives the pair of
ground engaging
track assemblies 108. A plurality of actuation devices (not shown in figure 1)
are positioned
within the operator compartment 118 to allow an operator to control functions
of the machine
including, for example, the drive function and manipulation of the boom-arm
structure 110
and the implement 112. Although this and other power machines illustrated in
this discussion
are power machines with operator compartments capable of carrying an operator,
it should be
appreciated that the embodiments discussed herein can be incorporated into
various other
power machines, including walk behind machines.
[0016] The power machine 100 illustrated in figure 1 also includes an
implement
assembly 122, which is operably coupled to the lower frame 106. The implement
assembly
122 illustratively includes a pair of lift arms 124 that are rotatably coupled
to the lower frame
106 at pivot points 126. A pair of actuators 128 is also coupled to the lower
frame 106 and lift
arms 124. A blade 130 is illustratively coupled to the lift arms 124. In one
embodiment, the
blade 130 is fixedly attached to each of the lift arms 124. Other arrangements
are
contemplated. For example, the blade 130 can alternatively be attached to an
attachment
mechanism such as a cross member (not shown) that is in turn attached to the
lift arms.
Alternatively still, the blade 130 can be pivotally attached to the lift arms
124. The actuators
128 are capable of rotating the lift arms 124 with respect to the lower frame
106 to raise and
lower the blade 130. While figure 1 shows two actuators 128, alternatively, a
single actuator
may be employed to control the angular position of the lift arms 124 with
respect to the lower
frame 106.
[0017] Figure IA illustrates power machine 100, with a pair of pallet forks
230 engaged
with the blade 130 so that the pallet forks 230 hang from the blade 130 when
mounted
thereto. For the purposes of this discussion, the blade 130 is a host
implement or implement
carrier that is capable of receiving one or more pallet forks 230. The pallet
forks 230 are an
illustrative example of an implement that can be attached to or engaged with
the host
implement, in this illustration, blade 130. Other implements besides forks or
pallet forks
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capable of being engaged with a host implement are contemplated. While the
forks 230 are
described as pallet forks with reference to this and other figures, it should
be appreciated that
forks 230 can engage and support other structures besides pallets and the use
of the term
pallet fork should in no way be construed to limit the interpretation of forks
230 to that of
being able to engage only pallets.
[0018] Figure 2 illustrates an undercarriage 200 similar to the undercarriage
102
illustrated in figure 1. Undercarriage 200 is configured to accept and be
operably coupled to
an upper rotatable frame of the type illustrated in figure 1. The
undercarriage 200 includes a
frame 202 to which a pair of support surface engaging track assemblies 204 are
coupled. A
pair of lift arms 206 (e.g., corresponding to lift arms 124 in figures 1 and
IA) are rotatably
coupled to the frame 202 at pivot points 208 and extend from the frame 202 on
one side
thereof. A cross member 210 is positioned between and attached to each of the
lift arms 206.
A bracket 212 extends from the cross member 210 and is configured to accept
and be secured
to an actuator (not shown in figure 2) of the type that is capable of
controlling the rotational
position of the lift arms 206. Frame 202 also has a bracket 214, which is
likewise capable of
accepting and being secured to the actuator. A blade 216 (e.g., corresponding
to blade 130
shown in figures 1 and IA) is illustratively coupled to each of the lift arms
206. The blade
216 includes a generally rectangular moldboard 218, having opposing ends 222
and 224,
which is capable of engaging and pushing material. The distance W between the
opposing
ends 222 and 224 is considered to be the width of the blade 216. The blade 216
also includes
a lip 220, which extends away from the top of the moldboard 218 and generally
toward the
frame 202 along all or substantially all of the width W of the blade 216. A
cutting edge 226
extends along a bottom of the moldboard 218 along all or substantially all of
the width W of
the blade 216. The cutting edge 226 is illustratively an edge of the moldboard
218.
Alternatively, the cutting edge is a piece of material that is fastened,
removably or otherwise,
to the moldboard 218. Like figure IA, a pair of pallet forks 230 is shown
engaged with the
blade 216, although it is to be understood one or more than two pallet forks
230 can be
engaged with blade 216 as may be advantageous to perform a particular
function. References
herein to engagement of pallet forks 230 with blade 218 should be interpreted
as engaging in
the same manner with similar blade embodiments, such as blade 130 shown in
figures 1 and
IA.
[0019] Figures 3A and 3B illustrate the pallet forks 230. For the purposes of
this
discussion, the pallet forks 230 in particular and implements of the type that
can engage a
host implement in general illustratively include an engagement portion and a
work portion.
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The pallet forks 230 include an engagement or mounting portion 232 and a work
portion in
the form of a tine 234, which extends from the mounting portion 232 at a
departure angle
236. Departure angle 236 is generally an obtuse angle, but any advantageous
departure angle
can be employed. The tine 234 has a length L that is advantageous for engaging
pallets or
other objects that may be carried on one or more pallet forks 230 when they
are engaged with
blade 216. The tine 234 has a tapered end 235, which allows the tine to more
easily engage
objects that it is employed to lift. The tines 234 of pallet forks 230 shown
in figures 3A and
3B are illustrative in nature and any acceptable shape, length, thickness, or
width may be
employed without departing from the scope of the discussion.
[0020] The mounting portion 232 includes an engagement structure 248 for
engaging the
blade 216 illustrated in figure 2. The engagement structure includes a lip
engagement
member 238. The lip engagement member 238 is shaped to allow the pallet fork
to engage
the lip 220 of blade 216. A face 240 extends between the lip 220 and the
cutting edge 226 of
the blade when the pallet fork 230 is coupled to the blade 216. It is not
necessary, however,
for the face 240 to conform to the shape of the moldboard 216. The engagement
structure 248
also includes a protrusion 242, which is configured to engage the cutting edge
226 by resting
against the cutting edge to provide some support between the pallet fork 230
and the blade
216.
[0021] Because the blade 216 has a lip 220 and a cutting edge 226 that extend
from one
side 222 to the other side 224 and have, in one embodiment, a similar cross
sectional profile
over all or part of the width W of the blade 216, the pallet forks 230 can
advantageously be
positioned along any location of the width W (or alternatively along
substantial portions of
the width W) of the blade 216, which provides flexibility in terms of what the
pallet forks can
engage. While figure 2 shows two pallet forks, it should be appreciated that
any number of
pallet forks can be attached to the blade 216, which can be advantageous when
engaging
some objects.
[0022] The pallet forks 230 are mounted onto the blade 216 by positioning the
pallet fork
230 so that it extends forward from the blade 216 and rotating the pallet fork
230 so that the
lip engagement member 238 is capable of engaging the lip 220. Then, the fork
is pulled
forward and rotated down until the protrusion 242 engages and rests against
the cutting edge
226. In some embodiments, the engagement portion is a rigid, unitary assembly
when
manufactured, although it may be assembled from a plurality of components such
as by
welding metal parts together. It should be appreciated that by unitary
assembly, it is meant
that the assembly is not capable of disassembly, adjustment, and does not
include a portion
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that is pivotable with respect to another portion of the assembly. That is,
the engagement
portion is manufactured so that the unitary assembly is configured to engage
and be accepted
by the implement carrier. Furthermore, the engagement and work portions are,
in some
embodiments, a unitary assembly when manufactured.
[0023] Returning to figure 2, undercarriage 200 provides a structure for
storage of pallet
forks 230 when they are not in use. Two pallet forks 230A are shown (in dashed
lines)
secured to the undercarriage 200. Two pairs of brackets 244 are mounted to the
frame 202.
The pairs of brackets 244 on each side of the frame 202 are aligned so that
the tines of pallet
forks 230A are accepted into each of the brackets. The pallet forks 230A are
illustratively
inserted into the brackets 244 from a side of the frame 202 that is opposite
to the side of the
frame that supports the lift arms 206. Once inserted into the brackets 244,
the pallet forks
230A are illustratively secured to the frame 202. Figure 4 illustrates a pair
of pallet forks
230A that are positioned within the frame of a work machine 300. An attachment
device 252
(in this figure a chain) is used to secure the pallet forks to each other and
to a mounting
structure 250, which extends from frame 202, or directly to the frame.
Although two sets of
pallet forks are shown in figure 2 (mounted pallet forks 230 and stored pallet
forks 230A
shown in dashed lines), this is shown for illustrative purposes to demonstrate
various
features. One skilled in the art will recognize that only one pair of pallet
forks will generally
be included, and those pallet forks can be moved between the mounted and
stored positions.
[0024] Figures 5 and 6 illustrate a cross section of a blade assembly 600 and
a portion of
pallet fork 602. In figure 5, the pallet fork 602 is shown in position to be
engaged with the
blade assembly 600 and in figure 6, the pallet fork 602 is shown in an engaged
position with
respect to the blade assembly 600. The blade assembly 600 includes a cross
section of a lift
arm 604 and an attachment structure 606, which couples the lift arm 604 to a
blade 608. An
end plate 610 is attached to one end of the blade 608. The blade 608 includes
a moldboard
636, with a cutting edge 612, and a lip 614 positioned along the bottom and
top, respectively
of the moldboard 636. Lip 614 is positioned adjacent an upper surface 615 of
the moldboard.
[0025] The pallet fork 602 includes a tine or work portion 624, a portion of
which is
shown in figures 5 and 6 and a mounting or engagement portion 626. The
mounting or
engagement portion is configured to engage an implement carrier, in this case
blade 608. In
exemplary embodiments, the engagement portion 626 is a unitary assembly. The
unitary
engagement portion assembly 626 can be made from any suitable material, but in
exemplary
embodiments is steel. Because the engagement portion of pallet fork 602 is a
unitary
assembly configured to engage blade 608, separate attachment or securing
mechanisms are
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not required to mount the pallet fork onto blade 608. In turn, the pallet fork
can be made to be
stronger or more durable than some conventional pallet forks and can be
fabricated less
expensively than some conventional pallet forks.
[0026] In pallet fork 602, a lip engagement member 616 includes material that
is formed
to include two adjacent contact areas 630 and 631, which engage adjacent
portions of the
blade 608, including the lip 614 of blade 608 and upper surface 615 of the
moldboard 636. To
aid in the engagement of pallet fork 602 without separate attachment
mechanisms, contact
areas 630 and 631 are not collinear or parallel with one another in an
exemplary embodiment.
Further, in some exemplary contact areas 630 and 631 are orthogonal or
substantially
orthogonal with one another, although the intersection of contact areas 630
and 631 may
include a radius. An angle between contact areas 630 and 631 of less than 90
can also be
used. The lip engagement member also includes a tab 632, which provides some
retention
force when the pallet fork 602 is engaged with the blade 608 as is shown in
figure 6. Thus,
tab 632 can also be referred to as a retention member. Retention member 632 is
positioned
opposing the contact area 631. Tab or retention member 632 has an inner edge
635, which is
also non-collinear with contact area 630 such that it forms a corner region
633 of the
retention member between contact 630 and edge 635. In exemplary embodiments,
contact
area 630 and edge 635 are oriented at an angle that is significantly less than
90 . There is a
gap 634 between an end of the tab 632 and the rest of the blade 608 so that
the lip 614 can be
accepted into the lip engagement member 616 through the gap. As shown in
figure 6, when
the engagement portion 626 of pallet fork 602 is fully engaged with blade 608,
lip 614 of
blade 608 is in contact with contact area 630 and upper surface 615 of
moldboard 636 is in
contact with contact area 631. However, border 635 of retention member 632 has
little or no
contact with blade 608. When the pallet fork 602 is engaged with the blade
assembly 606, the
lip engagement member 616 hangs over and surrounds a portion of the lip 614.
[0027] The pallet fork 602 includes a face 618 and a protrusion 620. The face
618 is
positioned such that when the pallet fork 602 is engaged with the blade 608,
the face 618 is
not in contact with moldboard 636. The pallet fork 602 also includes a cutting
edge contact
area 628, which is configured to be in contact with the cutting edge 612 when
the pallet fork
602 is engaged with the blade 608. As is shown in figure 6, at least a portion
of the tine 624 is
positioned below the cutting edge, although alternatively, the pallet fork 602
can be
structured to be entirely above or below the bottom of the cutting edge 612.
Thus, in the
illustrative embodiment, contact areas 630 and 631 and cutting edge engagement
contact
areas 628 represent first, second and third contact areas of the engagement
member that
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engage and abut portions of the blade 608 when the pallet fork 602 is accepted
onto blade
608. In some instances, when a load is applied to the work portion, the load
can cause
contact area 631 to lose contact with the upper surface 615 of the moldboard.
Instead, contact
area 630, corner region 633, and cutting edge engagement contact area 628
represent first,
second and third contact areas of the engagement portion 626 that abut
surfaces of the blade
608. In other instances, such as when the work portion 624 encounters an
obstacle, the pallet
fork 602 can temporarily rotate back. However, the retention member 632 may
engage the
lip 614 and prevent the pallet fork 602 from being disengaged from the blade
608. It should
be appreciated that the portions of the blade 608, namely, the lip 614 and the
upper surface
615 of the moldboard 636 and cutting edge 612, to which the contact areas of
engagement
portion 628 abut when the pallet fork 602 is hung over the blade 608 are
generally planar
surfaces. It should be further appreciated that the geometric shape of the
engagement portion
628, as described above, corresponds with the blade 602 to allow the pallet
fork 602 to be
engaged with the blade 608 without any sort of actuable locking mechanism on
the blade 608
or the pallet fork 602 provided to hold the pallet fork 602 to the blade 608.
[0028] While the embodiments above discuss pallet forks, it should be
understood that
other implements that can be positioned on the host implement of a power
machine such as
an excavator have been contemplated. The embodiments disclosed above are
illustrative in
nature and one skilled in the art would appreciate that changes can be made in
form and detail
without departing from the spirit and scope of the present discussion.
