U.S. patent application number 13/236594 was filed with the patent office on 2012-01-12 for fastener clearing systems.
Invention is credited to Robert E. Bender, Daniel D. Bloch.
Application Number | 20120006845 13/236594 |
Document ID | / |
Family ID | 37758869 |
Filed Date | 2012-01-12 |
United States Patent
Application |
20120006845 |
Kind Code |
A1 |
Bloch; Daniel D. ; et
al. |
January 12, 2012 |
Fastener clearing systems
Abstract
Fastener clearing systems and methods for a fastener delivery
system are provided. In one embodiment, a system includes an
extractor tool having one or more vacuum generators in fluid
communication with a catcher for retaining fasteners during
transport. The vacuum generators are selectively activated to draw
fasteners into the catcher. A backflow port is formed in the
extractor tool and introduces pressurized air into the catcher to
dislodge fasteners that adhere to the catcher after the vacuum
generators have been deactivated. The backflow port may be formed
in a fitting positioned between vacuum generators and securing the
vacuum generators to one another. The vacuum generators and fitting
may define a common fluid channel opening into a fastener seat
adapted to receive a portion of a fastener.
Inventors: |
Bloch; Daniel D.; (St.
Peters, MO) ; Bender; Robert E.; (St. Louis,
MO) |
Family ID: |
37758869 |
Appl. No.: |
13/236594 |
Filed: |
September 19, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11253209 |
Oct 18, 2005 |
8046898 |
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13236594 |
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Current U.S.
Class: |
221/278 |
Current CPC
Class: |
B23P 19/003 20130101;
Y10T 29/49947 20150115; B21J 15/32 20130101; B23P 2700/01 20130101;
B23P 19/005 20130101; Y10T 29/53478 20150115 |
Class at
Publication: |
221/278 |
International
Class: |
B65G 59/00 20060101
B65G059/00 |
Claims
1. (canceled)
2. The system of claim 29, further comprising a vacuum source for
providing the vacuum.
3-7. (canceled)
8. The system of claim 23, further comprising an end effector
coupled to a distal end of the delivery conduit.
9. The system of claim 23, further comprising a source of
pressurized air operatively coupled to the control system.
10. The system of claim 23, further comprising a proximity sensor
proximate the delivery conduit, the proximity sensor adapted to
sense proximity of the component.
11-22. (canceled)
23. A component delivery system comprising: a delivery conduit, an
unloading mechanism including an extractor catcher and a back flow
port in fluid communication with an upper surface of the extractor
catcher; and a control system for causing the extractor catcher to
drop a component into the conduit, and for commanding a supply of
pressurized air to the back flow port to create an overpressure in
the extractor catcher to ensure that the component is released from
the unloading mechanism and falls into the delivery conduit.
24. The system of claim 23, wherein the control system evaluates
whether the component has passed into the delivery conduit and
commands the overpressure if the component has not passed into the
delivery conduit.
25. The system of claim 24, wherein evaluating whether the
component has passed into the delivery conduit includes detecting
proximity of the component to the delivery conduit.
26. The system of claim 24, wherein evaluating whether the
component has passed into the delivery conduit includes detecting
proximity of the component to the catcher.
27. The system of claim 24, wherein evaluating whether the
component has passed into the delivery conduit includes waiting for
a delay period, and then evaluating passage of the component.
28. The system of claim 23, wherein the overpressure is created
automatically and systematically.
29. The system of claim 23, further comprising a component storage
device; and wherein the control system commands a vacuum to be
created within the extractor catcher to draw the component from the
component storage device and into the extractor catcher.
30. The system of claim 29, wherein the overpressure is created
after both removing the vacuum and evaluating passage of the
component.
31. The system of claim 29, wherein the vacuum is also used to lift
a component stack in the storage device, wherein a component is
drawn off the stack by the extractor catcher, and wherein remaining
components in the stack drop back after the drawn component enters
and seals the catcher.
32. The system of claim 23, wherein the extractor catcher includes
a component seat adapted to engage the component, and wherein
creating the overpressure includes releasing pressurized air
between the component and the component seat.
33. The system of claim 23, wherein the component is a fastener.
Description
FIELD OF THE INVENTION
[0001] This invention relates generally to systems and methods for
automated delivery of fasteners and, more specifically, to
pneumatic fastener delivery systems.
BACKGROUND OF THE INVENTION
[0002] Automated fastener delivery systems in aeronautical
applications should provide consistent operation. A typical
aircraft will include thousands of fasteners, which must be
installed quickly and cost-effectively. However, tools used to
handle the fasteners may become fouled by contaminants, oils, or
coatings that are carried by the fasteners. As a result, fasteners
may adhere to tooling rather than releasing predictably. Lodged
fasteners prevent consistent delivery of fasteners and cause delay
when they must be removed by hand.
[0003] Fastener handling tooling using suction heads to pick up or
move fasteners is particularly vulnerable to this problem. A
typical suction head creates a vacuum that draws the fastener into
the suction head and retains the fastener. The suction head may
then be moved to another location where the vacuum is deactivated
and the fastener is allowed to fall under the force of gravity. The
simplicity of operation and minimal moving parts of suction heads
make them very cost effective. However, when the suction head is
fouled by oils or other contaminants, a fastener may remain within
the grip of the suction head after the vacuum is deactivated.
Accordingly, although suction heads are an effective material
handling tool, there is room for improvement.
SUMMARY
[0004] The present invention is directed to methods and apparatus
for automated delivery of fasteners to an installation tool.
Embodiments of the invention enable consistent release of fasteners
and other components from a suction head of fastener handling
tooling in an automated fastener delivery system.
[0005] In one embodiment, an apparatus includes one or more
fastener storage devices and an unloading mechanism in
communication with the fastener storage device. The unloading
mechanism includes a fastener seat having a fluid channel coupled
thereto. A pneumatic control system regulates air flow between a
pressurized air source and the fluid channel. The control system
generates both overpressure and vacuum within the fluid channel.
Vacuum may be generated by pneumatic vacuum generators in fluid
communication with the fluid channel. Overpressure may be generated
by releasing pressurized air into the fluid channel through a
backflow port. In one embodiment, the backflow port is formed in a
fitting securing first and second vacuum generators to one
another.
[0006] In operation, a pneumatic control system generates a vacuum
within the fluid channel to draw at least one fastener from the
fastener storage device into the fastener seat. The unloading
mechanism is then moved to the delivery conduit. The control system
then generates overpressure within the fluid channel to expel the
fastener into the delivery conduit. In some embodiments, the vacuum
is first deactivated and the fastener is allowed to fall into the
delivery conduit. If the fastener fails to fall, then overpressure
is generated within the fluid channel to expel the fastener.
Whether the fastener falls may be determined by a proximity sensor
secured on or near the delivery conduit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Embodiments of the present invention are described in detail
below with reference to the following drawings.
[0008] FIG. 1 is a perspective view of a portable fastener delivery
system suitable for use with a fastener clearing system, in
accordance with an embodiment of the present invention;
[0009] FIG. 2 is a perspective view of a delivery conduit, in
accordance with an embodiment of the present invention;
[0010] FIG. 3 is a perspective view of an extractor mechanism, in
accordance with an embodiment of the present invention;
[0011] FIG. 4 is a side view of an extractor catcher, in accordance
with an embodiment of the present invention; and
[0012] FIG. 5 is a process flow diagram of a method for using a
fastener clearing system, in accordance with an embodiment of the
present invention.
DETAILED DESCRIPTION
[0013] The present invention relates to systems and methods for
automated delivery of fasteners to a fastener installation tool,
and more specifically, to improved fastener clearing systems and
methods. The present invention is suitable for use in fastener
delivery systems, including the type generally disclosed, for
example, in U.S. Pat. No. 6,688,489 issued to Daniel D. Bloch et
al., which is incorporated herein by reference. Many specific
details of certain embodiments of the invention are set forth in
the following description and in FIGS. 1 through 5 to provide a
thorough understanding of such embodiments. One skilled in the art,
however, will understand that the present invention may have
additional embodiments, or that the present invention may be
practiced without one or more of the details described in the
following description.
[0014] Referring to FIG. 1, a fastener delivery system 10 generally
includes an unloading mechanism 12 in communication with a fastener
storage device 14, wherein a control system 16 causes the unloading
mechanism 12 to remove a fastener having a specific configuration
from the fastener storage device 14 and transport the fastener to a
delivery conduit 18, wherein the fastener is delivered to a work
station. As shown, the fastener delivery system 10 may be disposed
within a portable platform, such as a mobile cart 20, so that a
variety of fasteners may be delivered to a plurality of work
stations located throughout a manufacturing facility.
[0015] The fastener delivery system 10 generally removes and
delivers fasteners using a pneumatic source 22. In one particular
embodiment, the pneumatic source 22 is shop air at 90 psi (pounds
per square inch). The pneumatic source 22 may be activated by the
control system 16 and is in communication with both the unloading
mechanism 12 and the delivery conduit 18 through flexible tubing
24. The fittings that connect the pneumatic source 22 and the
flexible tubing 24 are not shown for clarity. The pneumatic source
22 activates one or a plurality of vacuum generators 26 to remove a
fastener from the fastener storage device 14 and secure the
fastener within the unloading mechanism 12. The fastener storage
device 14 may include a plurality of tubes 28. The tubes 28 may
bear seals 30 for engaging the unloading mechanism 12. Once the
fastener is secured within the unloading mechanism 12, the control
system positions the unloading mechanism 12 adjacent the delivery
conduit 18, wherein the vacuum generators 26 are deactivated and
the fastener is transported through the delivery conduit 18 by
gravity and by pressurized air from the pneumatic source 22.
[0016] Referring to FIG. 2, the delivery conduit 18 further
comprises a drop station 32 in communication with a first fastener
delivery tube 34 and a second fastener delivery tube 36. As shown,
the drop station 32 further comprises a plurality of drop plates 38
that define chutes 40, through which the fasteners are dropped as
previously described. In one particular embodiment, the chutes 40
are tapered, although a variety of shapes may be employed to
effectuate transport of the fastener through the delivery conduit
18. The plurality of drop plates 38 are employed to facilitate
rapid interchangeability for a variety of fastener configurations.
Alternately, a single drop plate may be employed rather than the
plurality of drop plates 38.
[0017] As further shown in FIG. 2, the first fastener delivery tube
34 extends from the drop station 32 and is in communication with
the second fastener delivery tube 36. Generally, a fastener is
transported through the first fastener delivery tube 34 by gravity
until the fastener passes beyond a proximity sensor 42. When the
proximity sensor 42 detects the presence of a fastener, the
proximity sensor 42 notifies the control system 16, and the control
system 16 then activates the pneumatic source 22 (FIG. 1).
Accordingly, the pneumatic source 22 provides pressurized air
through the second fastener delivery tube 36 to deliver the
fastener to the work station. The workstation may include an end
effector suitable for installing the fastener.
[0018] The first fastener delivery tube 34 may be rigid in order to
facilitate efficient transport of the fastener by gravity.
Accordingly, in one particular embodiment, the first fastener
delivery tube 34 is fabricated from aluminum tube stock or other
rigid material commonly known in the art. The second fastener
delivery tube 36 may be flexible so that the fastener may be
delivered to a plurality of work stations throughout a
manufacturing facility. Accordingly, the length of the second
fastener delivery tube 36 may be varied to accommodate the required
distance from the portable fastener delivery system 10 to the work
station. The amount of time that the pneumatic source 22 provides
pressurized air through the second fastener delivery tube 36 is a
function of the length of the delivery tube and the fastener
configuration being delivered, and therefore, the amount of time
that pneumatic source 22 is activated must be adjusted according to
the length of the second fastener delivery tube 36.
[0019] Additionally, the inner diameter of the second fastener
delivery tube 36 should be sized appropriately to prevent tumbling
of the fastener along the length thereof, which is generally a
function of the overall size of the fastener. Generally, the inner
diameter of the second fastener delivery tube 36 may desirably be
slightly larger than the diameter of the fastener head yet smaller
than the overall length of the fastener to prevent tumbling.
Further, the second fastener delivery tube 36 may be fabricated
from relatively soft and flexible plastic such as nylon with a
relatively smooth inner surface to minimize friction between the
fastener and the inner wall of the second fastener delivery tube
36.
[0020] Referring to FIG. 3, the unloading mechanism 12 generally
comprises an extractor tool 44 having an extractor catcher 46
attached thereto. As further shown, in this embodiment, the vacuum
generators 26 are disposed at an upper end of the extractor tool 44
and the extractor catcher 46 is disposed at a lower end of the
extractor tool 44.
[0021] Although two (2) extractor tools 44, each having two (2)
vacuum generators 26, are illustrated herein, the portable fastener
delivery system 10 according to the present invention may comprise
any number of extractor tools 44 and vacuum generators 26 to remove
fasteners in accordance with specific operating requirements.
Therefore, the illustrated embodiment which uses two (2) extractor
tools 44 with two (2) vacuum generators 26 each should not be
construed as limiting the scope of the present invention.
[0022] Generally, the unloading mechanism 12 is positioned adjacent
the fastener storage device 14 using a linear X-Y positioner 48
that is activated by the control system 16 (FIG. 1). More
specifically, the linear X-Y positioner 48 positions an extractor
catcher 46 of the unloading mechanism 12 (FIG. 3) adjacent the
appropriate fastener storage tube 28 that contains the requested
fastener. Accordingly, the X and Y position of each fastener
storage tube 28 is stored within the control system 16 as described
in greater detail below. Additionally, the extractor tool 44, along
with the extractor catcher 46 attached thereto, may be translated
in the vertical direction with a vertical axis positioner 50 as
shown. The extractor catcher 46 is translated in the vertical
direction in order to engage the extractor catcher 46 with the
fastener storage tube 28 for removal of the requested fastener as
described in further detail below. Moreover, the vertical axis
positioner 50 may be pneumatically controlled and is therefore
activated by the pneumatic source 22.
[0023] In operation, the control system 16 activates the linear X-Y
positioner 48 to position the unloading mechanism 12 adjacent the
fastener storage device 14, and more specifically, to position an
extractor catcher 46 adjacent the appropriate fastener storage tube
28. Once the proper extractor catcher 46 is positioned adjacent the
appropriate fastener storage tube 28, the vertical axis positioner
50 moves the extractor tool 44 in the vertical direction until the
extractor catcher 46 abuts the seal 30.
[0024] Referring to FIGS. 3 and 4, once the extractor catcher 46 is
positioned against the seal 30 of the appropriate fastener storage
tube 28, the pneumatic source 22 (not shown) then activates the
vacuum generators 26, and as a result, one or more of the fasteners
52 within the fastener storage tube 28 move up against the
extractor catcher 46. Once the head of a top fastener 52 abuts the
extractor catcher 46 as shown, a seal may be created at the
interface between the top fastener 52 and the extractor catcher 46,
thereby causing the remaining fasteners 52 to drop back into the
fastener storage tube 28. As a result, the unloading mechanism 12
removes the top fastener 52 from the fastener storage device 14
without the need for a separate fastener escapement mechanism.
[0025] As shown in FIG. 4, the fastener 52 abuts an upper surface
54 of the extractor catcher 46, and may create a sealed (or at
least partially sealed) connection therebetween. In operation, the
at least partially sealed connection causes the remaining fasteners
to drop back into the fastener storage tube. As further shown, the
extractor catcher 46 also comprises a tapered inner surface 56 to
further facilitate ease of removal of the fastener 52 from the
fastener storage device 14. The upper surface 54 of the extractor
catcher 46 may be modified to accommodate various types of fastener
heads. A channel 58 opens into the upper surface 54 of the
extractor catcher 46 and is in fluid communication with the vacuum
ports of the vacuum generators 26.
[0026] In some applications and conditions, the fastener 52 may
tend to adhere to the surface 54. Adhesion may be caused, for
example, by contaminants such as oil or dust within the extractor
catcher 46. Adhesion may also result from coatings applied to a
fastener 52, such as a cetyl alcohol coating applied to prevent
galvanic corrosion at interfaces between dissimilar metals. Where
adhesion occurs, gravity may be insufficient to dislodge the
fastener 52 from the extractor catcher 46.
[0027] As further shown in FIG. 3, the extractor tool 44 may
include a backflow port 60 fluidly coupled to the upper surface 54
of the extractor catcher 46. The blackflow port 60 may be coupled
to a source of pressurized gas. For example, in one particular
embodiment, one of the flexible tubes 24 may connect the backflow
port 60 to the pneumatic source 22. When a fastener lodges in the
extractor catcher 46, pressurized air may be released through the
backflow port 60 to remove the fastener. In some embodiments,
pressurized air is automatically and systematically released to
ensure release of each fastener 52 each time the vacuum is released
to release the fastener 52 from the extractor catcher 46.
Alternately, in other embodiments, pressurized air is released
through the backflow port 60 only in instances where the fastener
52 fails to fall from the extractor catcher 46. In either case, the
control system 16 typically regulates the release of air through
the backflow port 60.
[0028] In the illustrated embodiment, the backflow port 60 is
formed in a fitting 62 (FIG. 3) which secures the two vacuum
generators 26 to one another. Forming the port 60 in the fitting 62
eliminates the need for separate parts for the port 60 and for
securing the vacuum generators 26 to one another thereby making the
extractor tool 44 more compact. The backflow port 60 may be
embodied as an aperture 64 formed in the fitting 62 and a nozzle
66, or other such fitting, secured thereto for connecting to the
pneumatic source 22. In one embodiment, the aperture 64 slopes
downwardly through the fitting 62, as shown in FIG. 3.
[0029] Various arrangements of the vacuum generators 26 and fitting
62 are possible. For example, a single vacuum generator 26 may be
used. The fitting 62 having the port 60 formed therein may be
disposed above or below the vacuum generator 26 (or generators 26).
The vacuum generators 26 and fitting 62 may form a continuous
channel opening into the upper surface 54 of the extractor catcher
46. Alternatively, the backflow port 60 may include a separate
channel independently connected to the upper surface 54.
[0030] In some embodiments, each extractor tool 44 includes a
backflow port 60. In others, such as the illustrated embodiment,
extractor tools 44 both with and without backflow ports 60 are
used. Such embodiments may be practical where multiple types of
fasteners are being handled but not all tend to adhere to the
extractor catcher 46.
[0031] FIG. 5 illustrates a method for using a fastener delivery
system 10 in accordance with an embodiment of the invention. At
block 80, the control system 16 receives a request for a specific
fastener configuration and identifies, through the execution of
control software within a computing device (not shown), which
fastener storage tube 28 within the fastener storage device 14
contains the proper fastener. At block 82, the control system
activates the linear X-Y positioner 48 to position the unloading
mechanism 12 in the proper X-Y position adjacent the fastener
storage device 14, and more specifically, to position the extractor
catcher 92 adjacent the appropriate fastener storage tube 28.
[0032] Once the extractor tool 44 is properly positioned, block 84
includes activating the pneumatic source 22 to cause the vertical
axis positioner 50 to force the extractor catcher 46 down against
the seal 30 disposed around the fastener delivery tube 28. When the
extractor catcher 46, or other sealing structure such as the shroud
94 disclosed in U.S. Pat. No. 6,688,489, abuts the seal 30, block
86 is executed, activating the vacuum generator 26 to cause at
least one of the fasteners within the fastener storage tube 28 to
move upward against the extractor catcher 46. When the top fastener
abuts the upper surface 54 of the extractor catcher 46, a seal is
at least partially formed therebetween and the remaining fasteners
(if any) fall back down into the fastener storage tube 28.
[0033] In block 88, the control system 16 positions the unloading
mechanism 12 over the delivery conduit 18. Block 88 may therefore
include activating the vertical axis positioner 50 to move the
extractor tool 44 up and away from the fastener storage device 14
and activating the linear X-Y positioner 48 to position the
unloading mechanism 12 in the appropriate X-Y position adjacent the
delivery conduit 18. More specifically, the linear X-Y positioner
48 positions the extractor catcher 46 adjacent the appropriate
chute 40 of the drop plate 38. Block 90 may include causing the
pneumatic source 22 to activate the vertical axis positioner 50 to
force the extractor catcher 46 down against the drop plate 38. The
extractor catcher 46 and drop plate 38 may form an air tight seal
at their contacting surfaces. Alternatively, Block 90 may be
omitted and the fastener dropped upon deactivation of the vacuum
generator 26 at block 92.
[0034] At block 92, the vacuum generator 26 is deactivated and the
fastener is allowed to drop into the first fastener delivery tube
34. Accordingly, the fastener is transported through the first
fastener delivery tube 34 by gravity. At block 94, the control
system 16 evaluates whether the fastener has fallen from the
extractor catcher 45. In one embodiment, this occurs as the
fastener is transported through the first fastener delivery tube 34
by gravity and past the proximity sensor 42 into the second
fastener delivery tube 36. If the fastener is sensed, then the
method proceeds to block 96. In other embodiments, block 94 may
include evaluating the output of a sensor capable of sensing the
fastener positioned on the drop plate 38, within the extractor
catcher 46, or at another point along the path of the fastener. At
block 96, the control system 16 activates the pneumatic source 22
to provide pressurized air through the second fastener delivery
tube 36 to deliver the fastener to a work station.
[0035] If the fastener is not sensed, then block 98 is executed. At
block 98 the back flow port 60 is activated, permitting air to flow
through the backflow port 60 for one or more short bursts (or
continuously). Bursts approximately one second in length have been
shown to be effective to dislodge some fasteners. The air flowing
through the backflow port may have any pressure effective to
dislodge the fastener. Shop air at 90 psi or reduced to pressures
from 60 to 80 psi has been shown to be effective. After releasing a
burst of air (or continuous flow of air) through the backflow port
60, block 94 may be reexecuted to evaluate whether the fastener has
dislodged from the extractor catcher 46. Blocks 94 and 98 may be
executed repeatedly until release of the fastener has been sensed
at block 94 or a specific number of iterations have occurred. After
the fastener is sensed at block 94, the delivery conduit may be
pressurized at block 96 to deliver the fastener to the work
station. The method may then return to block 80 and be repeated, or
the method may terminate.
[0036] In some embodiments, a block 100 may be executed before
block 94. Block 100 may include waiting for a period of time before
evaluating whether the fastener has been released from the
extractor catcher 46. The amount of time may approximate the
expected amount of time for a fastener to fall through the first
fastener delivery tube 34 from the extractor catcher 46 to a point
near the proximity sensor 50.
[0037] Various alternative embodiments of the method of FIG. 5 are
possible. In some embodiments, for example, the step of releasing
air through the backflow port 60 at block 98 may be executed for
each iteration of the method, rather than only in instances where a
fastener fails to fall due to gravitational forces. In other
embodiments, blocks 96 and 98 may be combined. In such embodiments,
pressurized air released from the backflow port 60 may serve both
to dislodge fasteners from the upper surface 52 and to force the
fastener along the first fastener delivery tube 34, the second
fastener delivery tube 36, or both.
[0038] Embodiments of the present invention may provide significant
advantages over the prior art. For example, by sensing the passing
of a fastener into the second fastener delivery tube, embodiments
of the invention ensure that those fasteners which adhere within
the extractor catcher are promptly detected so that appropriate
action may be taken. Further, embodiments of the invention provide
a backflow port which allow a fast, efficient, and cost effective
means of dislodging fasteners which adhere within the extractor
catcher. Thus, embodiments of the invention advantageously enable
consistent release of fasteners and other components from a suction
head of an automated fastener delivery system, thereby improving
the efficiency and reducing costs of the manufacturing
operation.
[0039] While preferred and alternate embodiments of the invention
have been illustrated and described, as noted above, many changes
can be made without departing from the spirit and scope of the
invention. Accordingly, the scope of the invention is not limited
by the disclosure of these preferred and alternate embodiments.
Instead, the invention should be determined entirely by reference
to the claims that follow.
* * * * *