U.S. patent application number 12/584217 was filed with the patent office on 2009-12-31 for linear actuated robotic packaging device and method.
This patent application is currently assigned to SMART MOTION ROBOTICS, Inc.. Invention is credited to Scott C. Gilmore.
Application Number | 20090320417 12/584217 |
Document ID | / |
Family ID | 43649549 |
Filed Date | 2009-12-31 |
United States Patent
Application |
20090320417 |
Kind Code |
A1 |
Gilmore; Scott C. |
December 31, 2009 |
Linear actuated robotic packaging device and method
Abstract
An end of arm tool that is capable of handling fragile items
such as eggs that are packaged in containers (e.g., egg cartons)
that require special handling is provided. The end of arm tool
comprises pivotal clamps operated by sliding-contact linear
actuators and return springs. A retractable gripper for placing
divider sheets between packages in the cases may be disposed above
the clamps and oriented 90 degrees from the clamps, so that the
clamps and gripper may be attached to the same tool without either
obstructing the operation of the other. In addition, a method of
loading packages, and optionally divider sheets, into cases using
the end of arm tool apparatus of the present invention is
provided.
Inventors: |
Gilmore; Scott C.; (Elgin,
IL) |
Correspondence
Address: |
RYNDAK & SURI LLP
200 W. MADISON STREET, SUITE 2100
CHICAGO
IL
60606
US
|
Assignee: |
SMART MOTION ROBOTICS, Inc.
Gilberts
IL
|
Family ID: |
43649549 |
Appl. No.: |
12/584217 |
Filed: |
September 2, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12217545 |
Jul 7, 2008 |
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12584217 |
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11478059 |
Jun 29, 2006 |
7409812 |
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12217545 |
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Current U.S.
Class: |
53/473 ;
53/235 |
Current CPC
Class: |
B25J 15/0253 20130101;
B25J 15/0052 20130101; B65G 47/91 20130101; B65G 57/005 20130101;
B65G 2201/0208 20130101; B25J 15/10 20130101; B65B 23/08 20130101;
B65G 47/90 20130101; B25J 15/0616 20130101; B65B 5/105 20130101;
B65G 57/04 20130101; B65B 61/207 20130101 |
Class at
Publication: |
53/473 ;
53/235 |
International
Class: |
B65B 5/00 20060101
B65B005/00 |
Claims
1. An end of arm tool comprising: first and second generally
opposed clamping members pivotally connected to a base about a
first clamping axis and a second clamping axis, respectively, the
first and second clamping axes being generally parallel to each
other; and first and second linear thrusters mounted for linear
movement relative to the base, the thrusters having contact ends
configured to extend toward and press against contact surfaces of
the first and second clamping members, respectively, to cause a
clamping end of each of the first and second clamping members to
pivot generally towards the clamping end of the other of the first
and second clamping members, and to produce a clamping force for
clamping a package between the first and second clamping ends.
2. The tool of claim 1, further comprising a pusher mechanism
adapted to push a package away from the clamping members in a
direction transverse to a distance between the clamping members to
release the package from the clamping members when the clamping
members partially obstruct the movement of the package away from
the clamping members.
3. The tool of claim 2, wherein the clamping members comprise
retention lips adjacent their clamping ends, the retention lips
being a portion of each clamping member turned inwardly toward the
opposed clamping member, wherein a distance between the retention
lips is shorter than a distance between the ends of the partially
obstructed package, and wherein the pusher mechanism is adapted to
push the partially obstructed package in the direction transverse
to the distance between the retention lips with sufficient force to
cause at least one of the package and the clamping members to be
deflected and to permit the clamped package to pass between the
retention lips and away from the clamping members.
4. The tool of claim 1, wherein the contact ends of the thrusters
include generally convex, curved contact faces configured for
sliding contact with the contact surfaces of the clamping
members.
5. The tool of claim 1, further comprising: first and second return
springs configured to urge the contact surfaces of the first and
second clamping members, respectively, to pivot toward and against
the contact ends of the first and second thrusters, respectively,
and to urge the first and second clamping ends apart from each
other.
6. The tool of claim 1, further comprising: third and fourth
generally opposed clamping members pivotally connected to the base
about a third clamping axis and a fourth clamping axis,
respectively, the third and fourth clamping axes being generally
parallel to each other and generally orthogonal to the first and
second clamping axes; and third and fourth linear thrusters mounted
for linear movement relative to the base, the thrusters having
contact ends configured to extend toward and press against contact
surfaces of the third and fourth clamping members, respectively, to
cause a clamping end of each of the third and fourth clamping
members to pivot generally towards the clamping end of the other of
the third and fourth clamping members, and to produce a clamping
force for clamping a package between the third and fourth clamping
ends; wherein the first, second, third and fourth clamping members
are configured to clamp a group of adjacent packages simultaneously
between the first and second clamping members and between the third
and fourth clamping members.
7. An end of arm tool comprising: first and second clamping members
movably mounted to generally opposite sides of a base for movement
of generally opposed clamping portions of the first and second
clamping members toward each other and into a clamping
configuration for clamping a package between the clamping portions
and movement of the clamping portions away from each other and out
of the clamping configuration to release a package clamped between
the clamping portions, wherein the clamping members are adapted to
clamp a horizontally oriented package at its ends, where the
package is located below the base when the end-of-arm tool is in a
clamping orientation; and a gripping tool movably mounted above the
base, the gripping tool having first and second gripping members
movable toward each other to grip a cardboard sheet between the
gripping members and movable away from each other to release a
cardboard sheet gripped between the gripping members; wherein the
end-of-arm tool has a profile defined by the horizontally outermost
extents of the base and the clamping members when the end-of-arm
tool is in the clamping orientation, wherein the end-of-arm tool is
adapted to be mounted to a robotic arm for movement to and from the
clamping orientation and a sheet placing orientation, wherein the
gripping tool is mounted for linear movement to and from a
retracted position located substantially within the profile of the
end-of-arm tool and an extended position in which at least a
portion of the gripping members extends outside the profile of the
end-of-arm tool, and wherein, when the end-of-arm tool is in the
cardboard sheet placing orientation and the gripping tool is in the
extended position, the at least a portion of the gripping members
extends downwardly below the base and the clamping members, and the
gripping tool is adapted to grip a substantially vertically
oriented cardboard sheet that is located substantially entirely
below the base and the clamping members.
8. The end-of-arm tool of claim 7, wherein the end-of-arm tool is
configured to be moved from the clamping orientation to the sheet
placing orientation and from the sheet placing orientation to the
clamping orientation by rotating the end-of-arm tool approximately
90 degrees about a substantially horizontal axis.
9. A method of packing a package into a case, the method
comprising: providing an end-of-arm tool mounted to a robotic arm,
the end-of-arm tool comprising first and second generally opposed
clamping members pivotally connected to a base about a first
clamping axis and a second clamping axis, respectively, the first
and second clamping axes being generally parallel to each other,
and first and second linear thrusters mounted for linear movement
relative to the base, the thrusters having contact ends configured
to extend toward and press against contact surfaces of the first
and second clamping members, respectively, to cause a clamping end
of each of the first and second clamping members to pivot generally
towards the clamping end of the other of the first and second
clamping members, and to produce a clamping force for clamping a
package between the first and second clamping ends; operating the
robotic arm to move the end-of-arm tool so that a package is
located between the clamping members; extending the linear
thrusters to clamp the package between the clamping members;
operating the robotic arm to move the end-of-arm tool to move the
package proximate to a desired location in the case; and retracting
the linear thrusters and permitting the clamping members to pivot
apart from each other to release the package and place the package
in the desired location.
Description
RELATED APPLICATIONS
[0001] This application is a continuation in part of U.S.
application Ser. No. 12/217,545, filed Jul. 7, 2008, which in turn
is a divisional of U.S. application Ser. No. 11/478,059, filed Jun.
29, 2006.
FIELD OF THE INVENTION
[0002] The present invention relates to an end of arm tool for a
robotic arm which is suitable for placing packages into cases.
Specifically, the present invention relates to an end of arm tool
suitable for packing egg cartons into a shipper case.
BACKGROUND OF THE INVENTION
[0003] The use of robotic arms has been readily adopted across
diverse industries because they increase efficiency in the
production process and reduce labor costs. The widespread use of
robotic arms is due largely to their versatility of performing
different tasks. This versatility is accomplished by the use of end
of arm tools (EOATs) that are specifically designed to perform
specialized tasks. For example, robotic arms are used to perform
complex operations that require the highest degree of accuracy and
precision, such as the manufacturing of circuit boards or computer
chips. In other industries, robotic arms have replaced manual labor
for tasks that were traditionally performed manually by humans such
as packing bottles into shipper cases, painting automobiles on the
assembly line, and many other similar tasks. All these tasks can be
performed by end of arm tools that have been specifically designed
to perform a task such as painting cars on the assembly line,
soldering transistors onto circuit boards, and loading bottles into
shipper cases.
[0004] Despite the many uses of robotic arms, there is still a need
to provide an end of arm tool that is capable of handling fragile
items that require special handling such as eggs that are packaged
in containers (e.g., egg cartons) which are then placed in shipper
cases. Heretofore, packing cartons of eggs into shipper cases has
remained a manual task.
SUMMARY OF THE INVENTION
[0005] According to one aspect of the present invention, an end of
arm tool comprises a plate having a top surface and a bottom
surface. At least one clamp actuator is located on the bottom
surface of the plate. The clamp actuator operates a clamp bar to
which a plurality of clamp fingers is connected. A vacuum cup
assembly is also located on the bottom surface of the plate.
[0006] In one embodiment of the present invention, the end of arm
tool further comprises at least one release actuator located on the
top surface of the plate that operates a pusher assembly located
along the bottom surface of the plate.
[0007] In another aspect, the invention is an end of arm tool
comprising gripping means for gripping a package by its top surface
and clamping means for clamping the edges of the package. The end
of arm tool may further comprise releasing means for releasing the
package from the end of arm tool.
[0008] According to another aspect of the present invention, a
method of packing cases is provided. The method comprises
connecting an end of arm tool comprising a vacuum cup assembly and
a plurality of clamp fingers to a robotic arm, and controlling the
robotic arm to place the end of arm tool over a package so that the
vacuum cup assembly makes contact with the top surface of the
package. A vacuum is generated so that the vacuum cup assembly
grips the top surface of the package. The clamp fingers are
retracted to clamp the edges (e.g., the ends, or the ends and
sides) of the package and the robotic arm is controlled to lift the
package and carry the package to a case. The method further
comprises moving the robotic arm into the case to place the package
in the case, releasing the package, and moving the robotic arm out
of the case.
[0009] In another aspect of the invention, a gripper is provided on
the end of arm tool for picking up a divider sheet, such as a sheet
of cardboard, and placing it in the case between layers or columns
of cartons.
[0010] According to yet another aspect of the invention, a
pivotal-clamp end of arm tool is provided. The pivotal-clamp
end-of-arm-tool includes first and second generally opposed
clamping members pivotally connected to a base about a first
clamping axis and a second clamping axis, respectively, the first
and second clamping axes being generally parallel to each other.
First and second linear thrusters are mounted for linear movement
relative to the base, the thrusters having contact ends configured
to extend toward and press against contact surfaces of the first
and second clamping members, respectively, to cause a clamping end
of each of the first and second clamping members to pivot generally
towards the clamping end of the other of the first and second
clamping members. The contact ends of the thrusters may include
generally convex, curved contact faces configured for sliding
contact with the contact surfaces of the clamping members. This
produces a clamping force for clamping a package between the first
and second clamping ends.
[0011] In one embodiment, the tool includes a pusher mechanism
adapted to push a package away from the clamping members in a
direction transverse to a distance between the clamping members to
release the package from the clamping members when the clamping
members partially obstruct the movement of the package away from
the clamping members. A pusher mechanism is not strictly necessary
in the absence of vacuum retention means, but may be advantageous
when the clamping members are restrained or prevented from fully
opening, as when the tool is inserted into a narrow box. For
example, in a preferred embodiment, the clamping members comprise
retention lips adjacent their clamping ends, the retention lips
being a portion of each clamping member turned inwardly toward the
opposed clamping member, wherein a distance between the retention
lips is shorter than a distance between the clamped ends of a
clamped package, i.e., a clamped length of the package. To
passively release the package, the clamping members must open so as
to decrease the distance between the retention lips sufficiently so
that the package may fall between them under its own weight. When
the clamping members are restrained or prevented from opening this
much, the package is still retained between the clamping members
even when the clamping force has been removed. In such a case, a
pusher mechanism is advantageously engaged to cause deflection in
the partially obstructed package, the clamping members, or both, so
that the partially obstructed package may pass between the
retention lips.
[0012] Preferably, the tool includes first and second return
springs configured to urge the contact surfaces of the first and
second clamping members, respectively, to pivot toward and against
the contact ends of the first and second thrusters, respectively,
and to urge the first and second clamping ends apart from each
other. This permits the tool to release a clamped package, while at
the same time preparing to clamp another package, when the
thrusters are retracted.
[0013] In one embodiment, the tool further includes third and
fourth generally opposed clamping members pivotally connected to
the base about a third clamping axis and a fourth clamping axis,
respectively, the third and fourth clamping axes being generally
parallel to each other and generally orthogonal to the first and
second clamping axes. The third and fourth clamping members may be
operated by third and fourth linear thrusters, similarly to the
first and second clamping members. The first, second, third and
fourth clamping members may be configured to clamp a group of
adjacent packages simultaneously between the first and second
clamping members and between the third and fourth clamping members.
For example, three one-dozen packages may be arranged side-by-side
in a row, and the first and second clamping members may clamp the
opposite ends of each package, while at the same time the third and
fourth clamping members clamp the outer side edges of the cartons
at the ends of the row, thus clamping their inner side edges flush
against the middle carton.
[0014] In still another embodiment of the invention, an end of arm
tool comprising egg-carton clamping and divider-sheet gripping
mechanisms is provided. The tool includes first and second clamping
members movably mounted to generally opposite sides of a base for
movement of generally opposed clamping portions of the first and
second clamping members toward each other and into a clamping
configuration for clamping a package between the clamping portions
and for movement of the clamping portions away from each other and
out of the clamping configuration to release a package clamped
between the clamping portions. The clamping members are adapted to
clamp a horizontally oriented package at its ends, where the
package is located below the base when the end-of-arm tool is in a
clamping orientation. A gripping tool is movably mounted above the
base, the gripping tool having first and second gripping members
movable toward each other to grip a cardboard sheet between the
gripping members and movable away from each other to release a
cardboard sheet gripped between the gripping members. The gripping
tool is mounted for linear movement to and from a retracted
position located substantially within the profile of the end-of-arm
tool and an extended position in which at least a portion of the
gripping members extends outside the profile of the end-of-arm
tool, where the profile of the end-of-arm tool is defined by the
horizontally outermost extents of the base and the clamping members
when the end-of-arm tool is in the clamping orientation. The
end-of-arm tool is adapted to be mounted to a robotic arm for
movement to and from the clamping orientation and a sheet placing
orientation. When the end-of-arm tool is in the cardboard sheet
placing orientation and the gripping tool is in the extended
position, the at least a portion of the gripping members extends
downwardly below the base and the clamping members, and the
gripping tool is adapted to grip a substantially vertically
oriented cardboard sheet that is located substantially entirely
below the base and the clamping members.
[0015] In one embodiment, the end-of-arm tool is configured to be
moved from the clamping orientation to the sheet placing
orientation and from the sheet placing orientation to the clamping
orientation by rotating the end-of-arm tool approximately 90
degrees about a substantially horizontal axis.
[0016] In yet another aspect of the invention, a method of packing
a package into an egg-carton container is provided. According to
the method, an end-of-arm tool as generally described above is
mounted to a robotic arm operable to move and manipulate the tool.
The robotic arm is operated to move the end-of-arm tool so that a
package is located between the clamping members, and the linear
thrusters are extended to clamp the package between the clamping
members. Then, the robotic arm is operated to move the end-of-arm
tool to move the clamped package proximate to a desired location in
the package container. When the package is at or just above the
desired location, the linear thrusters are retracted to permit the
clamping members to pivot apart from each other to release the
package and place the package in the desired location.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a detailed top view of the end of arm tool;
[0018] FIG. 2 is a front elevation view of the end of arm tool;
[0019] FIG. 3 is a side elevation view of the end of arm tool;
[0020] FIG. 4 is a side elevation view of a clamp finger;
[0021] FIG. 5 is a front elevation view of a clamp finger;
[0022] FIG. 6 is a side elevation view of a robotic arm having
attached thereto an end of arm tool;
[0023] FIG. 7 is front elevation view of the end of arm tool
holding three 12-egg cartons;
[0024] FIG. 8 is a front elevation view of the end of arm tool
holding two 18-egg cartons;
[0025] FIG. 9 is a front elevation view of another embodiment of
the end of arm tool;
[0026] FIG. 10 is a top perspective view of another embodiment of
the end of arm tool;
[0027] FIG. 11 is a detailed top view of the embodiment shown in
FIG. 10;
[0028] FIG. 12 is a side illustration of the embodiment shown in
FIG. 10 holding three 12-egg cartons;
[0029] FIG. 13 is a side illustration of the embodiment shown in
FIG. 10 in an open configuration; and
[0030] FIG. 14 is a front illustration of another embodiment of the
end of arm tool using a pusher mechanism to release a package into
a box.
[0031] FIG. 15 is an exploded view of an end of arm tool according
the embodiment shown in FIG. 10, attached to a robotic arm and
configured for placing a divider sheet.
DETAILED DESCRIPTION OF THE INVENTION
[0032] Referring to the figures generally and in particular to
FIGS. 1 through 3, there is illustrated an end of arm tool (EOAT)
10 that can place packages containing fragile items in cases. End
of arm tool 10 includes a main plate 12 having a top surface 14 and
a bottom surface 16. Vacuum cup assemblies 18 are attached to plate
12 at top surface 14 and extend through bottom surface 16. Release
actuators 20 are connected to a release actuator mount 22 that is
connected to bottom surface 16 of plate 12. A pusher assembly 24 is
attached to release actuator 20. Pusher assembly 24 is located
substantially parallel to plate 12 below bottom surface 16. Clamp
fingers 26 are connected to a clamp bar 28 that is operated by a
clamp actuator 30. A clamp actuator bracket 32 attaches clamp
actuator 30 to bottom surface 16 of plate 12.
[0033] The shape of plate 12 is typically a rectangle as shown.
Those skilled in the art will appreciate that the shape and
dimensions of plate 12 will depend on the particular application of
the end of arm tool. For example, for an end of arm tool that is
suitable for packing egg cartons in a shipper case, the dimensions
of plate 12 are such that plate 12 will fit within the inner walls
of the shipper case and can hold about three 12-egg cartons (six
rows by six columns of eggs for a total of 36 eggs) or about two
18-egg cartons (six rows by six columns of eggs for a total of 36
eggs). For example, for such an application plate 12 may be a
square having sides from about 9.5 inches to about 11 inches and
more preferably from about 10 inches to about 10.5 inches.
[0034] As shown in FIG. 1, in the exemplary embodiment there are
ten vacuum cup assemblies 18 arranged on plate 12. The number and
configuration of vacuum cup assemblies 18 can vary depending on
parameters such as the size, shape and weight of the items to be
packed. The arrangement of vacuum cups 18 shown in FIG. 1 is
designed to pick up three 12-egg cartons or two 18-egg cartons, as
best seen in FIGS. 7 and 8.
[0035] Clamp fingers 26 are typically configured in pairs. In the
exemplary embodiment shown there are five pairs of clamp fingers
26. Again, this arrangement is suitable for grasping the ends of
three 12-egg cartons or two 18-egg cartons (see FIGS. 7 and 8), and
the number and arrangement of clamp fingers 26 may be varied to
suit the size and shape of the items to be packed. Each clamp
finger 26 of a pair is attached to a corresponding clamp bar 28.
Clamp bars 28 are located opposite each other substantially
parallel to the front and back edge of plate 12. Each clamp bar 28
is operated by a pair of clamp actuators 30. Each clamp actuator 30
is attached to bottom surface 16 by a bracket 32. Clamp actuators
30 are preferably linear thrusters, but may also be pneumatic
cylinders, hydraulic cylinders, or other similar devices known to
those skilled in the art. Clamp fingers 26 are movable between two
positions as shown in FIG. 3 (with the extended or open position
shown in dashed lines).
[0036] Release actuators 20 are provided to operate pusher assembly
24. Release actuators 20 are preferably linear thrusters, but may
also be pneumatic cylinders, hydraulic cylinders, or other similar
devices known to those skilled in the art. Pusher assembly 24 can
have any shape and/or form suitable to push on the top surface of
the items currently held by clamp fingers 26 to release the items
from end of arm tool 10. For example, pusher assembly 24 may be in
the form of a pusher plate or one or more pusher bars.
[0037] Referring now to FIGS. 4 and 5, each clamp finger 26 has a
top section 34, a middle section 36, a bottom section 38, and a
fastener hole 40. Each clamp finger 26 attaches to clamp bar 28 at
top section 34 by means of a bolt or other fastener which is
inserted through fastener hole 40. Bottom section 38 is preferably
slightly curved at the tip to provide a hook to clamp onto the edge
of the package. Clamp finger 26 is typically made of a suitable
flexible material such as spring steel. Because clamp finger 26 is
both thin and flexible, it slips easily between a carton and the
inner wall of a case, and may be easily withdrawn after the carton
is placed in the case.
[0038] FIG. 6 illustrates a robotic arm 50 having attached thereto
an end of arm tool 10. End of arm tool 10 is attached to the face
plate 52 of robotic arm 50. FIG. 7 shows end of arm tool 10 lifting
three 12-egg cartons, and FIG. 8 shows end of arm tool 10 lifting
two 18-egg cartons. In FIGS. 7 and 8, the vacuum cups are seen in
contact with the top surfaces of the egg cartons, and the clamp
fingers are shown clamping the ends of the egg cartons.
[0039] More generally, end of arm tool 10 comprises a plate having
a top surface and a bottom surface as previously described,
gripping means attached to the bottom surface of the plate to grip
the top surface of a package, and clamping means attached to the
bottom surface of the plate to clamp the ends of a package. The
gripping means may be any suitable device capable of engaging the
top surface of the package and lifting the package, including,
without limitation, the vacuum cup assembly described above and
other such devices known to those skilled in the art. The clamping
means may include any suitable device capable of holding the
package together to prevent it from becoming open as the package is
lifted by the robotic arm. Suitable clamping means include, without
limitation, the clamp fingers connected to the clamp bar which is
operated by the retractable means. The retractable means may
include any suitable device capable of extending and retracting the
clamp bar such as clamp actuators as described above and other such
devices known to those skilled in the art.
[0040] The end of arm tool is preferably also provided with
releasing means attached to the bottom surface of the plate to
release the clamping means from the edges of the package. The
releasing means can include any suitable device capable of
disengaging the package from the end of arm tool. Examples of
suitable releasing means include, without limitation, the vacuum
cup assembly previously described wherein the air pressure can be
reversed to "blow off" the package from the gripping means, a
pusher assembly operated by pushing means, any other devices known
to those skilled in the art, and combinations thereof. As used
herein, the term "blow off" refers to applying positive air
pressure such that the package becomes disengaged from the vacuum
cup assemblies. The pushing means can include any suitable device
capable of moving the pushing assembly below the ends of the clamp
fingers. Suitable pushing means include, without limitation,
release actuators as described above and other similar devices
known to those skilled in the art. It will be apparent to those
skilled in the art that the package can remain attached to the end
of arm tool apparatus at the clamping means even though the package
has been disengaged from the gripping means. The releasing means
can include the combined operation of the vacuum cup assembly and
the pusher assembly as previously described.
[0041] The method of the invention is performed by connecting an
end of arm tool as described above to a robotic arm, and
controlling the robotic arm to place the end of arm tool over a
package so that the vacuum cup assembly makes contact with the top
surface of the package. Next, a vacuum is generated so that the
vacuum cup assembly grips the top surface of the package. Some
packages such as egg cartons can become open in some instances when
lifted by their tops, resulting in the undesired spillage of the
contents of the packages (i.e., eggs). To prevent this undesired
spillage, the method further comprises retracting the clamp fingers
to clamp the edges of the package. In a preferred embodiment of the
present invention, the clamp fingers are placed in a manner such
that the bottom-most part of the package can be grasped. The method
further comprises controlling the robotic arm to lift the package
and carry the package to a case, moving the robotic arm into the
case to place the package in the case, releasing the package, and
moving the robotic arm out of the case.
[0042] Releasing the package is preferably performed by reversing
the air pressure in the vacuum cup assemblies to "blow off" the
package from the vacuum cup assemblies, and/or by operating a
pusher assembly to push the package off the clamp fingers to
completely release the package from the end of arm tool.
[0043] In an alternative embodiment, clamp fingers may be provided
on all four sides of the main plate in order to clamp the packages
on their sides as well as their ends. This provides additional
protection against inadvertent opening of the cartons when they are
picked up. As shown in FIG. 9, side clamp fingers 60 and end clamp
fingers 62 are mounted on the sides and ends of main plate 64,
respectively. Side clamp fingers 60 and end clamp fingers 62 may be
separate and individual, as described above and shown in FIGS. 1
through 8, or may be formed as a unitary piece of material as is
the case with side clamp fingers 60 shown in FIG. 9. The material
is thin and flexible, such as 0.965 mm stainless steel.
[0044] In some applications, it is desirable to place a cardboard
divider or slip sheet between columns of cartons in the shipper
case. To automate the placement of the divider, a gripper 66 is
provided. As shown in FIG. 9, gripper 66 includes a pair of gripper
fingers 68. Gripper 66 is mounted on and moves laterally along
gripper slide 70. Gripper 66 is operated by gripper actuator 72
which is attached to main plate 64 via gripper actuator bracket
74.
[0045] In operation, gripper 66 is moved outward along gripper
slide 70 so as to extend beyond the edge of plate 64. Gripper
fingers 68 are opened to pick up a single sheet of cardboard from a
sheet feeder device (not shown). Gripper fingers 68 are then closed
to grasp the sheet, and the robotic arm to which the end of arm
tool is attached is operated to position the sheet in the case,
whereupon gripper fingers 68 are opened to release the sheet in the
desired position. Gripper 66 is then moved back along gripper slide
70 to its normal position. Gripper actuator 72 is preferably a
linear thruster, but may also be a pneumatic cylinder, hydraulic
cylinder, or other similar device.
[0046] Another alternative embodiment of the invention is
illustrated and described herein with reference to FIGS. 10-15. In
this embodiment, a pivotal-clamp end of arm tool 80 includes
pivotal clamps 82 pivotally mounted to a main plate 83 by hinges
84. Each clamp 82 includes chamfered corners 86, which are
beneficial for avoiding snags with box flaps when tool 80 is
inserted into a box for loading, and a retention lip 88 for
retaining a clamped side of an egg carton. With reference to FIG.
12, linear thrusters 90 for closing clamps 82 to clamp the ends and
side edges of an egg carton E include thruster pads 92 and are
mounted to the underside of a thruster mounting plate 94. While the
embodiment illustrated in FIGS. 10-13 and 15 includes four clamps
82, in should be noted that an end-of-arm tool may include only two
pivotal clamps for clamping only the ends or sides of an egg
carton, within the scope of the invention. Thruster mounting plate
94 is attached to a main riser 96 above a main plate 83 in
generally parallel, spaced-apart relation to main plate 83. Return
springs 100 are connected at one end below thruster mounting plate
94 and at the other end to hinges 84 at points above the pivotal
axes of clamps 82.
[0047] According to one method of use, a robotic arm is operated to
locate tool 80 just above egg cartons E to be clamped and moved,
with one pair of clamp members 82 flanking the ends and another
pair of clamp members 82 flanking the side edges of egg cartons E
as illustrated in FIG. 13. The clamp 82 in the foreground, oriented
for clamping the front end of egg cartons E, is illustrated in
phantom lines to reveal components that would otherwise be hidden
behind it. In the illustrated orientation of tool 80, thrusters 90
are in a retracted orientation in which thruster pads 92 have
receded to permit springs 100 to pull the top portions of clamps 82
inward toward main riser 96, thus causing the bottom ends of clamps
82 to pivot outwardly to an open orientation for receiving egg
cartons E to be clamped. The robotic arm is then operated to lower
tool 80 to a position in which a bottom of main plate 83 gently
abuts the tops of egg cartons E, and linear thrusters 90 are
extended in the direction indicated by arrows A to push thruster
pads 92 outwardly against clamps 82, thus causing the bottom ends
of clamps 82 to pivot inwardly in the direction indicated by arrows
C to clamp the ends and side edges of egg cartons E, as illustrated
in FIG. 12. Once egg cartons E are clamped, the robotic arm is
operated to move egg cartons E to a desired location, and thrusters
90 are retracted to permit springs 100 to open clamps 82 as
described above, thereby releasing egg cartons E and placing them
in the desired location.
[0048] Because vacuum cups or other suction means are preferably
omitted from the present embodiment, it will be noted that a pusher
assembly for releasing egg cartons E as described with respect to
the previous embodiments is not strictly necessary; rather, egg
cartons E may be released simply by opening clamps 82. However,
pusher assemblies 102 may be advantageously included in tool 80 to
assist in releasing egg cartons E when clamps 82 are prevented or
restrained from being fully opened. For example, as illustrated in
FIG. 14 for a two-clamp embodiment of tool 80, an egg carton
packing box B may be scarcely wider than tool 80 itself, so that
when thrusters 90 are retracted, thruster pads 92 recede inwardly
and lose contact with clamps 82, while the full opening of clamps
82 by springs 100 is obstructed by the lower portions of clamps 82
impinging interior side walls of box B, which may result in some
flexion of clamps 82 as illustrated. Due to the obstruction in the
illustrated case, clamps 82 are not opened wide enough to permit
egg carton E to pass between the ends of retention lips 88 under
the force of its own weight. In such cases, it is beneficial for
tool 80 to include pusher assemblies 102 to apply a sufficient
downward force to the top of egg carton E, as indicated by arrows
P, so that egg carton E may pass between retention lips 88 to be
released from clamps 82 as tool 80 is lifted vertically out of box
B by a robotic arm (not shown) in the direction indicated by arrow
D. To force egg carton E through a space that is narrower than the
length of egg carton E, the downward force provided by pusher
assemblies 102 may cause the ends of egg carton E, the ends of
retention lips 88, or both to flex or deflect somewhat. As shown,
pusher assemblies 102 include pusher cylinders 104 and push rods
106 for applying the releasing force to egg cartons E, but any
suitable pushing means may be employed.
[0049] Pivotal-clamp end of arm tool 80 optionally includes divider
dispenser gripping assembly 108, similar to gripper 66 and its
associated components described above. With reference to FIGS. 12
and 13, gripping assembly 108 includes a divider sheet gripper 110
with fingers 112 adapted to be moved toward and apart from each
other to grip and release a divider sheet, which may be a typical
cardboard divider sheet as commonly used in egg packaging. Gripper
110 is slidably mounted to the top of thruster mounting plate 94 by
gripper slide 114. As illustrated in FIGS. 12 and 13, the usual
position of gripper 110 is a retracted position in which no part of
gripper 110 extends horizontally beyond the profile of tool 80,
thus avoiding impingement of a packing box or other environmental
obstruction by gripper 110 while tool 80 is moved by a robotic arm
in its upright orientation for egg carton clamping, shown in the
figures.
[0050] Turning to FIGS. 12 and 15, the operation of gripper 110 is
illustrated. When it is desired to place a divider sheet in a
packing box, which may be a cardboard divider sheet D as shown in
the figure, gripper 110 is moved linearly along gripper slide 114
in the direction indicated in FIG. 12 by arrow B. In the extended
position of gripper 110 and gripper fingers 112, shown in FIG. 12
in dashed lines and indicated as 110' and 112', respectively,
gripper fingers 112 extend outside the profile of tool 80, and
gripper 110 may grip sheet D without sheet D impinging other
components of tool 80, as shown in FIG. 15. For placement of sheet
D, tool 80 is rotated into a position in which fingers 112 point
downward for holding sheet D in a vertical orientation. This step
may be performed before sheet D is gripped, as when a sheet feeder
(not shown) provides sheet D already in a vertical orientation, or
after sheet D is gripped, as when a sheet feeder (not shown)
provides sheet D in a horizontal orientation. A robotic arm
articulating member 116 and pivoting head 118 are shown exploded
from tool 80, for purposes of illustrating one manner in which a
robotic arm may reorient tool 80. In particular, tool 80 may attach
to pivoting head 118, and pivoting head 118 may carry out the
movement of tool 80 to and from its usual clamping orientation and
the sheet placement orientation by rotating with respect to
articulating member 116 about a horizontal axis, as indicated by
arrow R. Once sheet D is gripped and tool 80 is in the sheet
placement orientation, the robotic arm moves tool 80 to move sheet
D to a desired location, and fingers 112 are separated to release
and place sheet D.
Example
[0051] An end of arm tool according to the invention was
constructed for case packing of 36 eggs in either three 1-dozen
cartons or two 1.5-dozen cartons. The end of arm tool was
specifically designed to pick up plastic foam cartons off an
in-feed conveyor and place them into one of three different shipper
cases for shipment to grocery stores. The space utilized in the
shipper cases is the same for either the three 1-dozen cartons or
the two 1.5-dozen cartons. The three shipper cases sizes and
configurations are as follows: (1) 15 dozen case--3 dozen per
layer, 5 layers; (2) 24 dozen case--6 dozen per layer, 4 layers;
and (3) 30 dozen case--6 dozen per layer, 5 layers. Shipper case
sizes and dimensions may change from time to time, but do not alter
the operation of the end of arm tool. The controller for the
robotic arm may simply be reprogrammed for the different cases.
[0052] The EOAT was attached to the face plate of, and operated by,
a Model M-6iB/6s six-axis robotic arm supplied by FANUC Robotics
America, Inc. (Rochester Hills, Mich.). The structure, operation,
programming and control of the robotic arm are well known in the
art, and thus will not be described in detail herein. The
mechanisms on the end of arm tool (i.e., clamp actuators, release
actuators, gripper actuator) may be pneumatically actuated by
electrically-operated pneumatic solenoids, which are remotely
mounted. Commercial robotic arms provide the necessary electrical
and pneumatic connections for the end of arm tool.
[0053] The end of arm tool included a substantially square plate
measuring about 10.13 inches on each side. The plate was made of a
one-quarter inch thick polycarbonate material. Ten vacuum cup
assemblies were attached to the plate such that the vacuum cups
were located on the bottom surface of the plate. A release actuator
was mounted at each of the four corners of the plate using four
release actuator mounts attached to the bottom surface of the
plate. A pusher assembly was connected to the four release
actuators. The pusher assembly comprised two outer bars and one
inner bar. The two outer bars were connected each to two release
actuators. In addition, there were two linking bars that connected
the two outer bars to each other. The inner bar was attached to the
linking bars between the two outer bars. The end of arm tool
further comprised two clamp bars. Each clamp bar was connected to
two clamp actuators. The clamp actuators were attached to the
bottom surface of the plate using clamp actuator brackets. Five
clamp fingers that were made of 0.0625 inch thick spring steel were
attached to each clamp bar. The middle section of each clamp finger
was approximately 3.23 inches long, and its curved bottom section
formed a hook about 0.19 inches long with a radius of 0.12. These
dimensions are suitable for gripping standard egg cartons.
[0054] A shipper case was packed with egg cartons using the end of
arm tool described above. The end of arm tool was placed over the
egg cartons by the robotic arm, i.e., centered directly over three
12-egg cartons or two 18-egg cartons, so that the vacuum cup
assemblies made contact with the top surface of each egg carton. A
pneumatic solenoid was actuated which pressurized a vacuum
generator. The vacuum was supplied to the vacuum cup assemblies
causing the vacuum cups to grip the top surface of each egg carton.
After a short delay of about 0.5 seconds, the clamp fingers were
retracted via the pneumatic clamp actuators and clamp bars so that
the curved tips of the clamp fingers hooked underneath the center
lip of the ends of the lower portions of the egg cartons. The clamp
actuators were actuated to keep the clamp fingers normally
extended. The open and closed positions of the clamp fingers may be
seen in FIG. 3 (open position shown in dashed lines). The clamp
fingers were used to prevent the egg cartons from becoming open as
they were lifted by the vacuum cup assemblies.
[0055] After another short delay of about 0.5 seconds, the robotic
arm lifted the egg cartons and moved them into the shipper case. As
noted above, the clamp fingers used were made of spring steel so
that the clamp fingers hooked to the edge of the egg cartons could
easily fit in the narrow gap between the inside surface of the
shipper case and the egg cartons without damaging either the egg
cartons or shipper case. The robotic arm placed the egg cartons at
the proper height location, depending on the layer count of the
shipper case. Once in position, the vacuum solenoid was actuated to
turn off the vacuum, and the air pressure was reversed to supply a
positive air pressure to assist in releasing the vacuum cups from
the tops of the egg cartons, i.e., to "blow off" the tops of the
egg cartons. The clamp actuators were actuated causing them to
extend and to move the clamp fingers to the open position. The
inner surfaces of the shipper case normally prevent the fingers
from opening sufficiently for the clamp fingers to completely
release the egg cartons. Thus, the pusher assembly was used to
force the egg cartons off the clamp fingers. Once the air pressure
was reversed to the blow off mode and the clamp fingers were
extended, the robotic arm moved up approximately one-half inch. The
cartons had a tendency to come up with the robotic arm. The pusher
assembly was actuated by a pneumatic solenoid that pressurized the
release actuators so that they extended and pushed the pusher
assembly downward, thus releasing the egg cartons from the clamp
fingers. The normal state of the release actuators is retracted,
that is, pusher assembly up.
[0056] After another short delay of approximately 0.5 seconds, the
robotic arm moved the end of arm tool up and out of the shipper
case, the "blow off" air was turned off and the pusher assembly was
retracted to its normal position. The cycle was completed, and it
was repeated until the shipper case was filled with egg
cartons.
[0057] In an alternate method of operation, two layers of egg
cartons were placed on one side of a shipper case as described
above. The robotic arm was then moved to a cardboard sheet
dispenser, and the gripper was operated to pick up a single sheet
of cardboard from the dispenser by opening the gripper fingers,
placing them over the end of the sheet, and closing them to grip
the sheet. The robotic arm was operated to pull out the sheet, move
it up and over the shipper case, orient it vertically, slip it into
place in the case, and release it adjacent the egg cartons in the
case. The arm was then operated as described above to fill the
remaining space in the case with more egg cartons. As a result, the
cardboard sheet was positioned as a vertical divider between
columns of cartons. Of course, in other applications, a divider
could be placed horizontally between layers of cartons if
desired.
[0058] While the invention has been described with respect to
certain preferred embodiments, as will be appreciated by those
skilled in the art, it is to be understood that the invention is
capable of numerous changes, modifications and rearrangements and
such changes, modifications and rearrangements are intended to be
covered by the following claims.
* * * * *