Title: Compressive end effector
Abstract: Apparatus and method for holding an uncompressed bundle of product from the top with a vacuum assisted end effector and then simultaneously compressing the bundle from all sides at the same time with thin compression plates located about the periphery of a vacuum assisted end effector to form an evenly compressed product bundle that is then placed in a container with the compression plates between the product and the container walls. Once the bundle is received in the container, vacuum is removed; the inward force of the compression plates released and the compression plates removed vertically from between the product and the containers walls. The simultaneous compression from all sides provides even distribution of forces on the product and ensures that all product is compressed or deformed to the same degree. Using the apparatus described herein to place the bottom of the products gently onto the inside bottom of the container is further advantageous.
Patent Number: 7,017,961 Issued on 03/28/2006 to Parnell, et al.
| Inventors:
|
Parnell; Geoffrey (Moseley, VA);
Boyd; Paul (Midlothian, VA);
Robinson; Lee (Ruther Glen, VA);
Pearce; Tom (Ruther Glen, VA)
|
| Assignee:
|
Bakery Holdings LLC (Richmond, VA)
|
| Appl. No.:
|
914004 |
| Filed:
|
August 6, 2004 |
| Current U.S. Class: |
294/2; 294/64.1; 901/40 |
| Current Intern'l Class: |
B25J 15/06 (20060101) |
| Field of Search: |
294/2,641,65
414/627,737,752.1
901/40
251/61,612,635
|
References Cited [Referenced By]
U.S. Patent Documents
Primary Examiner: Kramer; Dean J.
Claims
What is claimed is:
1. A robotic end effector for picking product and building a bundle of product
retained thereon comprising:
A) a rectangular vacuum assisted plenum having opposing outer peripheral edges comprising;
i) a vacuum plenum fed by a vacuum inlet; plurality of plenum apertures in said
vacuum plenum; and
ii) in said plenum apertures, contact activated vacuum assisted suction cup assemblies comprising:
a) a cylindrical bellowed or corrugated cup defining a plurality of interconnected
bellows or corrugations of alternating, coaxial large and small diameter areas,
said bellowed cup comprising;
A) an open contact end; and
B) a valve end including a valve seat and a peripheral flange for engagement
with said plenum apertures;
iii) a threaded articulatable valve stem having first and second extremities;
iv) a valve plate intermediate said open contact end and said valve end in one
of said large diameter areas attached to said first extremity and including apertures
therein for the passage of a vacuum; and
v) a valve stop threaded onto said valve stem at said second extremity said valve
stop being of a size to engage said valve seat and including a central threaded
aperture; and
vi) compressive plates rotatably mounted along each of said outer peripheral edges;
said plurality of compressive plates being rotatable downward from said outer
peripheral edges to compress a bundle of product retained on said vacuum assisted plenum.
2. The robotic end effector of claim 1 Wherein the peripheral flange is integral
with said valve end.
Description
FIELD OF THE INVENTION
The present invention relates to robotic end effectors for picking products and
more particularly to a rotating end effector including peripheral compressive plates
that compact product picked by the end effector.
BACKGROUND OF THE INVENTION
The use of vacuum assisted picking end effectors to achieve the movement of product
is quite common in robotic packaging operations. In many of these automated packaging
operations the product being packaged must be assembled into a bundle on the end
effector prior to insertion into a suitable container or basket. Such is particularly
the case in the packaging of, for example, bakery products or the like, where a
bundle of bread loaves or the like are assembled on an end effector and then inserted
into a delivery basket or container.
Such a problem is particularly acute in those applications wherein it is required
that all of the products designated as a full layer in a container or basket (such
as the bread loaves shown in FIGS. 1 and 2 wherein bread loaves 10 are packaged
in shipping container or basket 12) be squeezed into conformance and forced
into the container. One prior art approach to this task was to place the product
into the container one at a time and then to force the last few in each direction
into the container. This often is undesirable because each object may be squeezed
differently from the others in the basket or container. If all the products are
pushed away to make room for an "un-squeezed" last object, then they are squeezed
to different degrees which is similarly undesirable. If the last product is squeezed
into the remaining space left over after all the un-squeezed objects are in place,
then the last object is squeezed to a different degree which is again undesirable.
The best way to accomplish the task of squeezing all the products into the basket
or container is to form the group of products in the proper pattern and orientation
and to squeeze from all sides inward at the same time until all products conform
to the containers shape and then to set the objects into the container. This has
been accomplished in various ways in the prior art. One method was to: 1) squeeze
the product in the X direction; 2) insert the group into the container at an angle
such that the first row is near and below the top of a Y direction container wall;
3) push from the other Y direction end of the product and force the objects up
against the container wall until the trailing products are past the opposite Y
direction wall; and 4) drop all of the thus compressed product into the container.
Another method is to loosely arrange the objects on a bottom support overtop of
the container (by mechanical or robotic means), to compress in all sides of the
objects until they are slightly smaller than the container walls, and then to quickly
remove the bottom support of the products and let them fall into the container.
The problem with this method is that the product often expands or springs out as
it falls and sometimes hangs up and does not drop all the way into the container.
Another problem with this method is that the product has to drop—which can
result in damage thereto. If the product(s) have to be picked with vacuum from
the top and temporarily supported in their descent then this is expensive and usually
prevents the use of a robot to form the pattern.
Thus, it is apparent that there exists a need for an apparatus, most desirably
an end effector that is capable of forming a required bundle of product, compressing
the bundle and then inserting the bundle into a shipping container or basket in
the compressed form thereby assuring that all individual product objects are uniformly
compressed and no damage is imparted to the product during insertion into the shipping
container or basket.
OBJECT OF THE INVENTION
It is therefore an object of the present invention to provide apparatus that
is
capable of picking a product to form a product bundle, compressing said product
bundle uniformly from all sides and placing the bundle into a shipping container
or the like without damage to the product.
It is another object of the present invention to provide such an apparatus that
operates as an end effector for the picking and placement of product.
SUMMARY OF THE INVENTION
According to the present invention an uncompressed pattern of product is
loosely held from the top with vacuum and then simultaneously compressed from all
sides at the same time with thin compression plates located about the periphery
of a vacuum assisted end effector to form an evenly compressed bundle that is then
placed in the container with the compression plates between the product and the
container walls. The vacuum is then removed; the inward force of the compression
plates released and the compression plates removed vertically from between the
product and the containers walls. The simultaneous compression from all sides provides
even distribution of forces on the product and ensures that all product is compressed
or deformed to the same degree. Using the apparatus described herein to place the
bottom of the products gently onto the inside bottom of the container is further advantageous.
DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 depict different product orientations in a shipping container
that can be compressed using the apparatus and method of the present invention.
FIG. 3 is a schematic side view of the compressive plate equipped end effector
of the present invention.
FIG. 4 is a schematic partially cut-away side view of a portion of a picking
system in accordance with the present invention showing the structure of the contact
activated vacuum assisted suction cup assembly of the present invention in each
of the open and closed positions.
FIG. 5 is a schematic view the vacuum portion of a vacuum assisted end effector
in accordance with the present invention.
FIG. 6 is a partially phantom side view of the suction cup portion of the contact
activated vacuum assisted suction cup assembly of the present invention.
FIG. 7 is a bottom view of the valve plate portion of the contact activated
vacuum assisted suction cup assembly of the present invention.
FIG. 8 is a partially phantom side view of the valve stop portion of the contact
activated vacuum assisted suction cup assembly of the present invention.
FIG. 9 is a side view of one embodiment of the valve stem portion of the contact
activated vacuum assisted suction cup assembly of the present invention
DETAILED DESCRIPTION
According to the present invention an uncompressed bundle of product is
loosely held from the top with vacuum and at the end of an end effector is simultaneously
compressed from all sides at the same time with thin compression plates located
about the outer periphery of a vacuum assisted end effector to form an evenly compressed
bundle that can then placed in the container with the compression plates between
the product and the container walls. The vacuum is then removed; the inward force
of the compression plates released and the compression plates removed vertically
from between the product and the containers walls. The simultaneous compression
from all sides provides even distribution of forces on the product and ensures
that all products are compressed or deformed to the same degree. Using the apparatus
described herein to place the bottom of the products gently onto the inside bottom
of the container is further advantageous.
Referring now to FIG. 3 that depicts a schematic side view of a preferred
embodiment of the end effector
18 of the present invention, loaves
10
are held to end effector
18 through the action of suction cups
40.
End effector
18 includes a vacuum plenum
41 as well as a vacuum inlet
45. Of particular interest in FIG. 3 are compression plates
42 that
are hydraulically (or otherwise, i.e. electrically, mechanically, etc) actuated
by hydraulic cylinder assembly
44. While in the depiction presented in FIG.
3, for clarity, only two compression plates
42 are shown, it will be readily
apparent to the skilled artisan that such compression plates
42 are located
on all sides, i.e. about the outer periphery or outer peripheral edge
43
of end effector
18 to provide uniform and preferably simultaneous compression
from all sides of the bundle of loaves attached to end effector
18. During
picking of product
10 all of compression plates
42 are in the position
indicated at the left of FIG. 3. Upon completion of picking of a unit or bundle
of product
10 for insertion into container or basket
12 (see FIGS.
1 and 2) all peripheral compression plates
42 are activated simultaneously
through the action of hydraulic cylinders
44 and rotate downward to the
position indicated at the right of FIG. 3 thereby uniformly compressing product
10 into a product bundle suitable for insertion into container or basket
12. Once insertion into container or basket
12 is complete, end effector
18 is raised through the action of gantry (not shown in the Drawings) and
compression plates
42 again raised, i.e. rotated upward, to the position
shown at the left of FIG. 3 preparatory to another pick of product
10.
While any suitable arrangement of suction cups
40 supplied with a suitable
vacuum via plenum
41 on end effector
18 can be used successfully,
an end effector that provides "on demand" vacuum due to the presence of product
10 under a specified suction cup
40 or array of suction cups
40
is specifically preferred. Such a vacuum system is referred to herein as a "contact
activated vacuum assisted suction cup" and is described below.
Referring now to FIGS.
4 and
6-
9, the preferred contact
activated vacuum assisted suction cup assembly
100 of the present invention
comprises a corrugated or bellowed cup
120 comprising an open end
140
and a valve end
160. Corrugated cup
120 further includes coaxial
large diameter areas
180 and small diameter areas
200 defined by
the interconnected corrugations or "bellowed" configuration of bellowed cup
120.
At the valve end
160 of bellowed cup
120 is a valve seat
220
(best seen in FIGS. 4 and 6) that closes valve end
160 except at the aperture
240 in valve seat
220. Valve end
120 also incorporates a peripheral
and preferably integral flange
620 whose purpose is the engagement of apertures
in a plenum
540 as described below.
Inserted through aperture
240 is valve stem
260 (best seen
in FIGS. 4 and 9). As depicted on the attached drawings, valve stem
260
comprises a simple bolt, however it will be readily appreciated that more sophisticated
custom machined, welded etc. structures could be substituted for this simple design.
Valve stem
260 has a first extremity
280 and a second extremity
300.
Attached to first extremity
280 in the accompanying Figures is a valve stop
320 (best seen in FIGS. 4 and 8) and attached to the second extremity
300
is a valve plate
340 (best seen in FIGS. 4 and 7). Attachment of valve stop
320 to valve stem
260 is accomplished by the simple expedient of
inserting valve stem
260 through aperture
360 in valve stop
320.
Valve stop
320 may be located on valve stem
260 by, for example providing
threads
400 on the inner surface
380 of valve stop
320 as
shown, or by simply securing valve stop
320 with a nut
420 on both
the upper and lower surfaces
440 and
460 of valve stop
320.
In the embodiment depicted in the accompanying Figures, valve stop
320 is
threaded onto valve stem
260 and nut
420 is used to secure it in
position. Quite obviously, valve seat
220 and valve stop
320 must
be of relative sizes as to seal aperture
240 when valve assembly
100
is in the closed position depicted at the left in FIG. 4.
As will be apparent to the skilled artisan, valve stop
320 and valve seat
220 should be fabricated from a material or materials that allow for tight
sealing therebetween upon contact of these two elements of the assembly of the
present invention as shown at the left in FIG. 4. Thus, rubber or polymeric materials
that provide such sealing should be used. Alternatively, a coating of a suitable
such material can be applied over a "non-sealing" metallic or polymeric structure
to provide the appropriate sealing effect.
At the opposing extremity of valve stem
260, valve plate
340 is
attached to valve stem
260 by the insertion of valve stem
260 through
aperture
480 at the approximate center of valve plate
340 and securing
it in position between the head
510 of valve stem
280 with nut
520.
As best seen in FIG. 4, valve plate
340 is of a diameter D (see FIG. 7)
that is of approximately the same as or, slightly larger than diameter D′
of large diameter areas
180 (see FIG. 4) so that it can be inserted into
one of large diameter areas
180 intermediate valve end
160 and open
end
140. In this configuration, valve plate
340 will remain in position
in corrugated cup
120 even when an individual assembly
100 is not
in use. Apertures
350 are provided in valve plate
340 to permit a
vacuum to be drawn through valve plate
340 upon contact of open end
140
with an object to be lifted
500 as explained more fully below.
While valve stop
320 and valve plate
340 are described herein
as being located at "the extremities
280 and
200 of valve stem
260,
it will be apparent to the skilled artisan that the term extremity as used in this
context is meant to indicate at or near the opposing ends of valve stem
260
and not necessarily at the very end thereof.
Depicted schematically in FIG. 4, is a plenum
540 having a vacuum
inlet
560. Apertures
580 in plenum
540 engage valve end
160
of corrugated cup
120 through the engagement of peripheral flange
620
with the periphery of aperture
580. As shown at the left of FIG. 4, when
no object to be lifted is present, corrugated cup
120 remains in its fully
extended position, valve stem
260 with attached valve stop
320 remains
in it fully lowered position, valve stop
320 engages valve seat
220
and no vacuum can pass through valve end
160. Thus, if no product
500
contacts open end
140, no vacuum is allowed to escape through the vacuum
cup assembly
100 of the present invention and only those assemblies
100
whose open ends
140 are contacted by product
500 are activated as
described below. Upon contact of open end
140 with an object to be lifted
500, corrugated cup
120 collapses upward as shown at the right of
FIG. 4 due to upward pressure applied to open end
140 against object
500
by downward movement of plenum
540, or if desired by design, upward movement
of product
500. In the case depicted at the right, upon the application
of upward pressure to corrugated cup
120 (for the reason just described),
valve stem
260 is also caused to travel upward resulting in the disengagement
of attached valve stop
320 with valve seat
220 thereby allowing vacuum
from plenum
540 to pass through apertures
350 to tighten the "grip"
of corrugated cup
120 on object
500.
Depicted schematically in FIG. 5 is a bottom views of a picking device
640
comprising a plenum
540 having an array of contact activated vacuum assisted
suction cup assemblies
100 mounted therein. As just described, such a picking
device
640 can be used to pick up and move any arrangement of sizes of objects
to be lifted
500 without concern for which of the individual contact activated
vacuum assisted suction cup assemblies
100 lies in registration therewith,
since those assemblies not in contact with one or more of contact activated vacuum
assisted suction cup assemblies
100 will not result in the leakage or loss
of vacuum due to the closed condition of valve end
160. Thus the need to
add "chambering" (as was done in the prior art) or refitting of the picking array
when different product is being picked is obviated.
There as thus been described a novel end effector incorporating peripheral
compression plates that uniformly compress a bundle of products attached to the
end effector through the action of vacuum assisted suction cups. Such an apparatus
provides the uniform bundle compression desired for inserting the bundle into a
shipping container or basket in an undamaged fashion.
*
