U.S. patent application number 12/607632 was filed with the patent office on 2010-02-25 for method for determining and setting material release mechanism timing for a material feed mechanism.
This patent application is currently assigned to Vamco International, Inc.. Invention is credited to Matthew C. Crowell, Bryan P. Gentile, Daniel G. Lukas, Vaughn H. Martin.
Application Number | 20100044409 12/607632 |
Document ID | / |
Family ID | 32069955 |
Filed Date | 2010-02-25 |
United States Patent
Application |
20100044409 |
Kind Code |
A1 |
Martin; Vaughn H. ; et
al. |
February 25, 2010 |
Method for Determining and Setting Material Release Mechanism
Timing for a Material Feed Mechanism
Abstract
The present invention includes a method of determining the
correct timing of a material release mechanism of a material feed
mechanism and includes the steps of: cycling a press mechanism
through a working portion of a tooling mechanism; monitoring the
press mechanism position; determining, by a location device, the
desired timing for the material release mechanism to release
contact with material; and correlating the desired material release
mechanism timing to the press mechanism position.
Inventors: |
Martin; Vaughn H.;
(Gibsonia, PA) ; Lukas; Daniel G.; (Pittsburgh,
PA) ; Gentile; Bryan P.; (Pittsburgh, PA) ;
Crowell; Matthew C.; (Delmont, PA) |
Correspondence
Address: |
THE WEBB LAW FIRM, P.C.
700 KOPPERS BUILDING, 436 SEVENTH AVENUE
PITTSBURGH
PA
15219
US
|
Assignee: |
Vamco International, Inc.
Pittsburgh
PA
|
Family ID: |
32069955 |
Appl. No.: |
12/607632 |
Filed: |
October 28, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11782936 |
Jul 25, 2007 |
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12607632 |
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10416945 |
Nov 7, 2003 |
7287678 |
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PCT/US01/43698 |
Nov 16, 2001 |
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11782936 |
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60249149 |
Nov 16, 2000 |
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Current U.S.
Class: |
226/2 |
Current CPC
Class: |
H01L 27/153 20130101;
Y10T 83/0481 20150401; B21D 43/021 20130101; B65H 23/1884 20130101;
Y10T 83/159 20150401; B41J 2/45 20130101; Y10T 83/148 20150401;
B21D 43/09 20130101 |
Class at
Publication: |
226/2 |
International
Class: |
B65H 23/00 20060101
B65H023/00 |
Claims
1. A method for determining the correct timing of a material
release mechanism of a material feed mechanism for feeding
elongated strip material, the method comprising the steps of:
cycling a press mechanism through a working portion of a tooling
mechanism; monitoring the press mechanism position; determining, by
a location device having a controller, the desired timing for the
material release mechanism to release contact with the material by
sensing the contact of at least one component of the tooling
mechanism with the material by: placing the material through the
material release mechanism of the material feed mechanism;
positioning the material with the leading edge through a first
station of the tooling mechanism; punching a first hole in the
first portion of the material with a punching device; incrementally
advancing the material such that an alignment device is located
substantially above the first hole; moving, or attempting to move,
the material as the alignment device is entering the hole; and
correlating the desired material release mechanism timing to the
press mechanism position.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 10/416,945 filed Nov. 7, 2003, which is the national phase of
International Application No. PCT/US01/43698 filed Nov. 16, 2001,
designating inter alia, the United States, which claimed the
benefit of U.S. Provisional Patent Application No. 60/249,149 filed
Nov. 16,2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to stamping systems
having material feed mechanisms and, in particular, to a method and
apparatus for determining and setting a material release mechanism
timing for a material feed mechanism.
[0004] 2. Description of Related Art
[0005] Typically, parts made with an automated stamping press
utilize a progressive die set. The progressive die set uses
multiple stations, each station typically containing at least one
punching or forming punch and a mating die or dies. Continuous
strip material, from which the part will be made, is incrementally
fed through the die set, progressing from station to station with
an automated feeding device. A material feed mechanism
intermittently moves the strip material a distance, corresponding
to the distance between each die station, while the die set is
open. This mechanism then stops the material at each station when
the die set closes. Examples of prior art material feed mechanisms
may be found in U.S. Pat. Nos. 5,755,370; 5,868,296; 5,915,293; and
5,808,465.
[0006] Alignment devices are commonly used in a progressive die set
to position the strip in the die set for each subsequent operation
more accurately than is possible with the material feed mechanism.
The most commonly used and most easily understood alignment device
is a tapered or beveled point pilot positioning pin or a plurality
of such pins. The pilot positioning pin is mounted in the moving,
usually the upper, die shoe. Typically, a hole of slightly larger
diameter than the diameter of the pilot positioning pin is punched
in the continuous strip material in a first station during the
first closure of the die. The automated material feed mechanism
then moves the material a predetermined distance corresponding to
the distance between subsequent die stations. Upon subsequent die
positioning pin, which is longer in length than the working
punches, enters the hole created by the punch and locates the
material accurately.
[0007] Pilot positioning pins may be used at any number of
subsequent die stations. In order for the pilot positioning pin, or
other alignment device, to effectively position the material
accurately, the material feed mechanism must relinquish its grip on
the strip material. The timing of the release function of the
material feed mechanism is critical, as premature release may allow
the material to move out of position too far for the pilot
positioning pin to be effective. Alternatively, if the material
feed mechanism releases the strip material too late or not at all,
tension will be developed in the strip material when the pilot
positioning pin enters the hole. This may cause hole deformation
with resulting improperly positioned material. This improperly
positioned material will cause the manufacture of malformed parts
and can damage the pilot positioning pin as well as the die
set.
[0008] Various methods of releasing the strip material from the
material gripping mechanism are well known in the prior art.
Typically, these methods utilize cams, air cylinders, or various
other devices. Technology currently exists for both setting and
maintaining precise material release mechanism timing between the
material feed mechanism and the stamping press. For example, see
U.S. Pat. No. 5,720,421. Furthermore, this technology provides for
infinite variation in release timing, as well as a convenient means
for adjusting this timing. However, no technology exists for
determining the precise press slide or press mechanism position
when the alignment device contacts the material and the material
gripping mechanism release should occur.
[0009] Determining the precise point in the press stroke when the
material feed mechanism should release its grip on the strip
material is difficult due to two primary problems. First, the
alignment device is typically located in a position which makes it
difficult or impossible to visually inspect. Second, the nature of
a flywheel driven mechanical stamping press makes it difficult to
precisely position the press slide in small increments. The process
of moving the press slide in small incremental movements is called
"inching" or "jogging" and is accomplished by repeated engagement
of the press clutch for short periods of time. This causes a motion
that is very erratic and makes it difficult to precisely position
the press slide, in order to verify the correct position of the
alignment device relative to the strip material. The difficult
nature of the current methods is best illustrated by example.
[0010] Current methods exist for determining and setting the
correct material release mechanism timing, but these methods
typically require the press operator to locate the material in the
die in a position which will allow the punching of the initial
locating hole. The operator must then effect movement of the press
ram, to close the die, punching the locating hole in the material.
The material is then progressed a single progression, thereby
positioning the material correctly to allow the alignment device to
contact the material on a subsequent closure of the die. The
operator then "inches" or "bars" the press to the point at which
the material alignment device begins to contact the material. The
point at which the material alignment device begins contact with
the material is determined visually or, alternatively, by grasping
the material in hand, moving or trying to move the material, and
feeling for resistance to movement of the material provided by the
alignment device. Having determined the press position where the
material alignment device begins to contact the material, the
operator then adjusts the material feed mechanism to release the
hold on the material at this point or slightly before this point in
the press stroke. This process is then repeated and adjustments are
made until proper timing of the material release mechanism is
verified.
SUMMARY OF THE INVENTION
[0011] It is, therefore, an object of the present invention to
provide a method for determining the correct timing of the material
release mechanism. It is another object of the present invention to
provide a method for setting the correct timing of the material
release mechanism. It is a further object of the present invention
to provide an automated system for accurately determining release
mechanism timing. It is a still further object of the present
invention to provide a method and apparatus that is capable of
disengaging contact with a material immediately prior to engagement
by an alignment device.
[0012] The present invention includes a method for determining the
correct timing of a material release mechanism of a material feed
mechanism, including the steps of: (1) cycling a press mechanism
through a working portion of a tooling mechanism; (2) monitoring
the press mechanism position; (3) determining, by a location
device, the desired timing for the material release mechanism to
release contact with the material; and (4) correlating the desired
material release mechanism timing to the press mechanism position.
In another embodiment, the method also includes the step of
adjusting the timing of the material release mechanism to the
determined desired material release mechanism timing.
[0013] The present invention is also directed to a stamping system
for working a material. This stamping system includes a press
mechanism configured to punch holes in the material. The stamping
system also includes a material feed mechanism having a material
release mechanism for feeding material to the punching mechanism,
and a location device for monitoring the press mechanism position
in determining a desired material release mechanism timing.
[0014] The present invention, both as to its construction and its
method of operation, together with additional objects and
advantages thereof, will best be understood from the following
description of specific embodiments when read in connection with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a side schematic view of a stamping system
according to the present invention;
[0016] FIG. 2 is a front view of a material feed mechanism of the
stamping system in FIG. 1;
[0017] FIG. 3 is an edge view of the material feed mechanism in
FIG. 2;
[0018] FIG. 4 is a side schematic view of a tooling mechanism
according to the present invention;
[0019] FIG. 5 is a flow diagram of a method according to the
present invention; and
[0020] FIG. 6 is a graph of press mechanism position versus
material position.
DETAILED DESCRIPTION OF THE INVENTION
[0021] As illustrated in FIGS. 1-3, the present invention is
directed to a stamping system 10, which includes a press mechanism
12, a material feed mechanism 14 and a material dispenser 16. The
material feed mechanism 14 is used to feed an elongated_strip of
material 18 from the material dispenser 16 through the material
feed mechanism 14 and into the press mechanism 12. This press
mechanism 12 typically includes a tooling mechanism 17 having an
upper die shoe 20 and lower die shoe 22. The upper die shoe 20 is
mounted to a press slide 24 in the press mechanism 12. The upper
die shoe 20 of the tooling mechanism 17 has a punching device 26
and an alignment device 28 mounted on its underside. The punching
device 26 is constructed so that it is capable of piercing or
punching the material 18. In the preferred embodiment, the
alignment device 28 is a pilot positioning pin 30. As discussed
above, this upper die shoe 20 is mounted to the press slide 24
which, in turn, moves up and down in relation to the lower die shoe
22. The lower die shoe 22 of the tooling mechanism 17 is mounted to
a bolster plate 32 rigidly mounted to a fixed press bed 34.
[0022] The material 18, typically, but not exclusively, in the form
of a continuous strip, is fed to and moves between the upper die
shoe 20 and the lower die shoe 22. Further, the press mechanism 12
also includes a driver having a crankshaft 36 to drive or move the
press slide 24 towards and away from the lower die shoe 22, as
represented by arrow A. As detailed in FIGS. 1-3, the material feed
mechanism 14 includes a feed drive roll motor 38, typically a servo
motor, to power and drive the feed drive roll 40, which advances
the material 18 through the material feed mechanism 14.
[0023] A material release mechanism 42 includes a material gripping
mechanism 44, which works along with the feed drive roll 40 to grip
the material 18. Typically, this material gripping mechanism 44 is
a secondary drive roll. The material gripping mechanism 44 is
mounted in a pivot frame 46, which is pivotably mounted to a
material feed mechanism frame 48. The material release mechanism 42
also includes an actuator 50, typically pneumatic, capable of
applying downward pressure on the pivot frame 46, thereby allowing
the material gripping mechanism 44 to grip the material 18 between
the material gripping mechanism 44 and the feed drive roll 40.
[0024] As seen in FIG. 3, it is also envisioned that the material
feed mechanism 14 includes a motor 52 to drive a release screw 54,
which mates with a nut 56, for effecting the movement of the pivot
frame 46 against the force of actuator 50. It is this release screw
54 and nut 56 arrangement which allows the material gripping
mechanism 44 to move away from the feed drive roll 40, thereby
releasing the grip pressure on the strip material 18.
[0025] In order to determine a desired material release mechanism
timing, the stamping system 10 also includes a location device 58.
In the preferred embodiment, this location device 58 includes a
controller 60 that monitors the press mechanism 12 position and
determines the desired timing for the material release mechanism 42
to release contact with the material 18. Further, this controller
60 can perform the correlation between the desired material release
mechanism 42 timing to the press mechanism 12 position. It is also
envisioned that the location device 58 include a first feedback
device 62 to monitor, collect and transmit information regarding
the press mechanism 12, as well as its parts, to the controller 60.
Similarly, a second feedback device 64 may be used to monitor,
collect and transmit information regarding the material feed
mechanism 14, and its parts, to the controller 60.
[0026] In a preferred embodiment, the location device 58 uses the
first feedback device 62 to monitor the crankshaft 36 of the press
mechanism 12. Next, this first feedback device 62 communicates the
angular position information of the crankshaft 36 to the controller
60. The second feedback device 64 is mounted to the feed drive roll
motor 38 and is used to monitor and communicate the angular
position of the feed drive roll motor 38 to the controller 60.
Finally, the controller 60 computes position error information
based on the required motion of the feed drive roll motor 38, and
the measured actual motor angular position. Controller 60 may also
compute the required torque command for the feed drive roll motor
38, based on the position error information computed above. This
torque command is sent to the motor 38. Also, the required torque
commands, by definition, may be used and/or referred to as the
measured torque of the motor 38. Although the location device 58
has been described as monitoring the specific equipment discussed
above, it is envisioned and discussed in greater detail
hereinafter, that this location device 58 may be used to monitor
and determine the desired material release mechanism 14 timing and
press mechanism 12 position based upon any of the physical
characteristics of the stamping system 10 parts and equipment,
including the feed mechanism and the press itself.
[0027] As illustrated in FIG. 5, the present invention also
includes a method for determining the correct timing of the
material release mechanism 14. In order to determine this timing,
the press mechanism 12 is cycled through the working portion of
the_alignment device 28 of the tooling mechanism 17. The press
mechanism 12 position is monitored. The above-described location
device 58 may be used to determine the desired timing for the
material release mechanism 42 to release contact with the material
18. Typically, the desired timing for release is immediately prior
to contact with the material 18 by the alignment device 28, or in
this embodiment, the pilot positioning pin 30. Next, the determined
desired material release mechanism 14 timing is correlated to the
press mechanism 12 position. Overall, this will allow the material
release mechanism 42 to disengage the material 18, allow the pilot
positioning pin 30 to contact the material 18 and align it, before
the material gripping mechanism 44 again contacts the material 18
and the material feed mechanism 14 continues the feed. After the
desired timing has been determined, the actual material release
mechanism 42 timing may be adjusted to the determined desired
material release mechanism 42 timing.
[0028] In the preferred embodiment, the strip material 18 is
positioned with the leading edge through the first die station,
containing the punching device 26. The press mechanism 12 is then
cycled through one complete press stroke, with the punching device
26 piercing or punching a hole 66 into the strip material 18. The
material 18 is then advanced by the material feed mechanism 14 a
predetermined distance, short of the die progression. This will
position the material 18, such that the pilot positioning pin 30 is
located substantially above the previously punched hole 66, but
slightly misaligned. This condition is illustrated in FIG. 4, with
the misalignment greatly exaggerated. In practice, this
misalignment is small, typically only 0.003 inches to 0.008
inches.
[0029] The next step is to cycle the press mechanism 12 through the
working portion of the alignment device 28, and typically through
another complete press stroke, while the controller 60
simultaneously monitors the position of the feed drive roll motor
38. When the upper die shoe 20 closes, the pilot positioning pin 30
enters the prepunched hole 66, and the material 18 is forced into a
final aligned position. This causes movement of the material
gripping mechanism 44 and the feed drive roll motor 38, which are
gripping the material 18. When the press cycle is complete, the
controller 60 analyzes the information gathered and correlates the
movement of the material release mechanism 42 (including the
material gripping mechanism 44) and the feed drive roll motor 38 to
the position of the press mechanism 12, thereby determining the
press mechanism 12 position where the pilot positioning pin 30
entered the strip 18. An example of this correlated data is shown
in FIG. 6. Finally, the material feed mechanism 14, specifically
the material release mechanism 42, is programmed to release the
material 18 at the calculated press mechanism 12 position for
subsequent press cycles. In this preferred embodiment, the
controller 60 automatically sets the correct release point and
stores the information for future use.
[0030] The pilot positioning pin 30 has a guide end 68, which is
typically beveled. When the press mechanism 12 enters the working
portion of the tooling mechanism 17, the guide end 68 of the pilot
positioning pin 30 is partially engaged with the hole 66. Due to
the misalignment, a side wall of the guide end 68 contacts an inner
edge of the hole 66, such that the material 18 is moved along a
first axis (arrow B) as the side wall of the guide end 68 continues
through the hole 66. The desired material release mechanism 42
timing is based upon the linear movement of the material 18 along
this first axis B. Further, the linear movement of the material 18
along this first axis B after the guide end 68 has fully engaged
the hole 66 may be measured. The linear movement of the material 18
may then be correlated to the position of the press mechanism 12,
to determine the desired material release mechanism 42 timing. It
is also envisioned that the angular rotation of the feed drive roll
40 caused by the linear movement of the material 18 may be
correlated to the position of the press mechanism 12, to determine
the desired material release mechanism 42 timing. If the press
mechanism 12 includes a press ram, the linear movement of the press
ram position may be measured and correlated to the movement of the
material 18, to determine the desired material release mechanism 42
timing.
[0031] It is also envisioned that the disturbance force produced
upon contact of the pilot positioning pin 30 with the material 18
may be measured. As above, this measurement may be used to
determine the desired material release mechanism 42 timing. The
torque exerted upon the feed drive roll 40 after the guide end 68
of the pilot positioning pin 30 has fully engaged the hole 66 may
also be measured. Similarly, the force exerted upon the material
gripping mechanism 44 may be measured. These measurements may then
be used to determine the desired material release mechanism 42
timing. Material 18 movement at the material dispenser 16 may also
be measured and used to determine the desired material release
mechanism 42 timing. The torque exerted upon the feed drive roll
40, the force exerted upon the material gripping mechanism 44, as
well as the feed drive roll motor 38 position error may all be used
to determine the desired material release mechanism 42 timing. It
is envisioned that the controller 60, together with appropriate
feedback devices (62, 64) may be used to monitor, transmit, and
calculate the desired release mechanism 42 timing based upon any of
these measurements.
[0032] Overall, the present invention is a stamping system 10 and
method for determining and adjusting the desired timing of a
material release mechanism 42. When using the controller 60, the
present invention is an automated system, which eliminates the
prior art guesswork previously used by operators to set the
material release mechanism 42 timing. This, in turn drastically
increases productivity and reduces both operator error and possible
operator safety concerns.
[0033] The present invention determines the precise press mechanism
12 (typically the press slide 24) position when the alignment
device 28 is about to contact the material 18 and the material
release should occur. It is this precise point in the press stroke
when the material feed mechanism 14 should release its grip on the
strip material 18. This precise point, as described in detail
above, is determined by the controller 60 based upon the linear or
angular movements of certain components and subcomponents of the
stamping system 10. However, it is also envisioned that one or more
sensors can be used and positioned adjacent or in the vicinity of
the punching device 26 or the alignment device 28. Such sensors
could sense contact or exact positioning of the alignment device 28
and/or the punching device 26, and this information could be used
to determine the material release mechanism 42 timing. For example,
the contact of either the punching device 26 or the alignment
device 28 could be sensed when an electrical circuit is complete,
thereby determining the timing for material 18 release. Also,
sensors could be used to directly measure the movement of material
18 to determine the timing of material 18 release. Alternatively,
the material 18 could be mechanically dithered (or moved back and
forth) as the alignment device 28 is entering the hole 66. Using
the forward and backward contact of sidewalls of the guide end 68
of the pilot positioning pin 30, the controller 60 could determine
the material release mechanism 42 timing.
[0034] Furthermore, although the aforementioned preferred
embodiments reference feed drive roll 38 and/or drive rolls in the
material feed mechanism 14 and the material gripping mechanism 44,
it is envisioned that the material feed mechanism 14 could utilize
sliding gripper(s) for advancing the strip material 18 and/or
sliding or stationary gripper(s), as a part of the material feed
mechanism 14 and/or the material gripping_mechanism 44 and/or as a
part of the material release mechanism 42.
[0035] This invention has been described with reference to the
preferred embodiments. Obvious modifications and alterations will
occur to others upon reading and understanding the preceding
detailed description. It is intended that the invention be
construed as including all such modifications and alterations.
* * * * *