U.S. patent application number 13/347740 was filed with the patent office on 2012-07-12 for strapping head for steel-wire coil or steel-bar bundle.
Invention is credited to Todd Bulak, Jens Nylander, Matthew Palfreman.
Application Number | 20120174803 13/347740 |
Document ID | / |
Family ID | 46454246 |
Filed Date | 2012-07-12 |
United States Patent
Application |
20120174803 |
Kind Code |
A1 |
Palfreman; Matthew ; et
al. |
July 12, 2012 |
STRAPPING HEAD FOR STEEL-WIRE COIL OR STEEL-BAR BUNDLE
Abstract
A strapping head having a feed unit for advancing a strap
downstream and tensioning the strap around an object to be strapped
and a crimp unit downstream of the feed unit for crimping two
sections of the strap to each other has for each of the units an
electric drive motor. In addition the head is provided with an
electronic programmable controller connected to both of the units
for operating same in accordance with a resettable program.
Inventors: |
Palfreman; Matthew;
(Charlton, MA) ; Bulak; Todd; (Fiskdale, MA)
; Nylander; Jens; (Rutland, MA) |
Family ID: |
46454246 |
Appl. No.: |
13/347740 |
Filed: |
January 11, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61431465 |
Jan 11, 2011 |
|
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Current U.S.
Class: |
100/8 ;
100/29 |
Current CPC
Class: |
B65B 27/06 20130101;
B65B 27/10 20130101; B65B 13/187 20130101 |
Class at
Publication: |
100/8 ;
100/29 |
International
Class: |
B65B 13/18 20060101
B65B013/18; B65B 13/22 20060101 B65B013/22; B65B 13/24 20060101
B65B013/24; B65B 27/00 20060101 B65B027/00 |
Claims
1. In a strapping head having: feed means for advancing a strap
downstream and tensioning the strap around an object to be
strapped; and crimp means downstream of the feed means for crimping
two sections of the strap to each other, the improvement wherein
each of the means has an electric drive motor; and the head is
provided with an electronic programmable controller connected to
both of the means for operating same in accordance with a
resettable program.
2. The strapping head defined in claim 1, wherein each of the
motors has its own respective such electronic controller.
3. The strapping head defined in claim 1, further comprising
clamping means for arresting the strap during crimping by the
crimping means, the clamping means having its own electric drive
motor.
4. The strapping head defined in claim 1 with jaw wear
compensation.
5. The strapping head defined in claim 1 wherein the head can
produce variable strength bindings.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is related to copending provisional
application 61/431,465 filed 11 Jan. 2011.
FIELD OF THE INVENTION
[0002] The present invention relates to a strapping head. More
particularly this invention concerns a device for securing a loop
of strap around a workpiece, for instance a coil of steel wire or a
bundle of steel bars.
BACKGROUND OF THE INVENTION
[0003] Strapping machines in the steel industry are typically used
to strap coils and bundles of bar materials. Coils are typically
formed on a wire rod mill and are then compacted in a compactor
machine and then strapped as part of this process; the heads are
incorporated in to this machine. Bar Bundles are generally
processed through a cooling bed and then collected in a bundle area
to be strapped together in predetermined bundle weights.
[0004] Typically these two types of machine use very different
strapping technology and thus strapping heads, the compactor
strapping head can be very complex, incorporating various custom
hydraulic manifolds and cylinders. The bundle heads are typically
somewhat less complex due to the simpler requirements of the
bundling area.
[0005] Both types of strapping head rely on hydraulic and pneumatic
media and feedback from proximity sensors to determine if the
commands given are carried out and the strapping sequence has been
completed. Thus these machines can be considered dumb or open-loop
systems as they cannot make adjustments themselves and must report
to an off machine programmed logic controller (PLC) to control
them.
[0006] Furthermore, no adjustment for operating conditions can be
made by the operator either without dismantling the machine and
refurbishing it in a workshop.
OBJECTS OF THE INVENTION
[0007] It is therefore an object of the present invention to
provide an improved strapping head for sheet-steel coils or steel
bars.
[0008] Another object is the provision of such an improved
strapping head for sheet-steel coils or steel bars that overcomes
the above-given disadvantages, in particular that addresses the
problems above.
SUMMARY OF THE INVENTION
[0009] A strapping head having a feed unit for advancing a strap
downstream and tensioning the strap around an object to be strapped
and a crimp unit downstream of the feed unit for crimping two
sections of the strap to each other has according to the invention
for each of the units an electric drive motor. In addition the head
is provided with an electronic programmable controller connected to
both of the units for operating same in accordance with a
resettable program.
[0010] In accordance with the invention each of the motors has its
own respective such electronic controller. Furthermore according to
the invention the head has a clamping unit for arresting the strap
during crimping by the crimper. The clamping means or unit having
its own electric drive motor.
[0011] With this system, because of the on-board intelligence, the
heads themselves hold the programming to complete the process. They
do not rely on the outside control of a PLC, and each motion within
in the head handshakes with the next until the process is complete.
If a motion is not complete the head captures this and restarts the
process until it is completed, or switches to a manual mode so that
an operator can trouble shoot the system and complete the actions
manually.
[0012] Each part of the overall process is the responsibility of a
respective movement controller coupled to an actuator, and each
movement controller controls only the movements required for the
defined process and tells the next controller via a handshake
signal that the movements are complete. If the handshake is not
complete the controller tries again or switches to manual and
alerts the operator that there is an issue with the particular
motion or part of the process.
[0013] The prior-art heads controlled via hydraulic media can not
do this and the operator has no way of knowing what is wrong in the
process and the whole sequence must be started again, or the strap
scraped and the whole binding process started again.
BRIEF DESCRIPTION OF THE DRAWING
[0014] The above and other objects, features, and advantages will
become more readily apparent from the following description,
reference being made to the accompanying drawing in which:
[0015] FIGS. 1, 2, and 3 are perspective views from different
angles of the strapping head according to the invention;
[0016] FIG. 4 is a section taken through the crimper of the head as
shown by line IV-IV of FIG. 6;
[0017] FIG. 5 is a section taken through the clamp of the head as
shown by line V-V of FIG. 6; and
[0018] FIG. 6 is a longitudinal section through the head taken
along line VI-VI of FIGS. 5.
DETAILED DESCRIPTION
[0019] As seen in FIGS. 1, 2, 3, and 6, the apparatus of this
invention basically comprises a feeder FE, a guide GU, a crimper CR
(FIG. 4), and a clamp CL (FIG. 5).
[0020] The feeder FE at the upstream end of the strapping head has
a master controller 1 that holds the master program and that is
used for handshaking with all the other below-mentioned movement
controllers. It also controls the pinch of the unillustrated strap
fed in from the left in FIGS. 1, 2, and 6.
[0021] Furthermore the feeder FE has an electric hybrid stepping
motor 2 whose torque and angular position is controlled by the
master controller 1 and that is connected to a multiscrew actuator
3. A movement controller 6 reporting to the master controller 1 is
effective via another hybrid stepping motor 5 to a lower pinch
roller 8 cooperating with an upper pinch roller 7 to advance the
unillustrated strap downstream through a guide track 9 of the guide
GU.
[0022] At the downstream end the clamp CL has a movement controller
10 and a hybrid stepping motor 11 effective through a multiscrew
actuator 12 on movable clamp jaws 13 cooperating with a clamp anvil
15.
[0023] The crimper CR downstream of the clamp CL has a movement
controller 15 reporting like the movement controllers 6 and 10 to
the master controller 1 and effective through another hybrid motor
16 and multiscrew actuator 17 on binding/cutting jaws 19
cooperating and forming a quick-release coupling 20 with an anvil
18 on a mount 29. The coupling 20 has pivot shafts 21 extending
between a front plate 30 and back plate 31.
[0024] Other movement controllers 22 for secondary crimp are
connected through their own hybrid stepping motors 23 and
multiscrew actuators 24 to crimp jaws 25. A quick-release pin 26
and a crimp slide block 27 are connected via crimp links 28.
Similarly clamp links 32 are connected to a clamp link block.
[0025] Due to the onboard intelligence and the configuration of the
movement controllers, it is possible for the process to be tailored
to individual strapping processes. This makes the system easy to
adapt to different processes.
[0026] The use of this configuration of movement controllers makes
it possible for the crimp/binding depth to be easily reset. This
important for two distinct reasons.
[0027] 1. Binding strength: The shallower the deformations in the
strap the stronger the joint. For example with a 3 mm
indentation/perforation the strength of the binding can be as high
as 92% of the parent material. With a indentation/perforation of
3.5 mm the strength reduces to 88% of the parent material. This has
been proved with actual binding samples tested to destruction.
[0028] 2. Jaw wear: The jaws wear over time and eventually will not
bind the material. With a conventional head there is no way to
compensate for this. But with the use of individual movement
controllers the travel of the jaw stack can be increased to
compensate for jaw wear thus increasing the usable time of the
machine between rebuilds.
[0029] This adjustability is also carried through to the strap feed
pinch roll. Strap feed speeds, strap tension torque and strap pinch
forces are all variable. This allows the machine to operate with
various different strap media without significant adjustments to
valves flow control and pressure control. All of the above items
are infinitely variable, within the desired operating range.
[0030] Since the heads incorporate their own on board intelligence
and movement controllers there is no need for an external control
structure. This allows the strapping head to be incorporated into
any strapping process be it coil, bar or other. The only signals
required to make the head operate in any process architecture are a
go signal from the machine they are incorporated into. Thus the
heads return a complete signal when the process is complete or an
error signal when the heads switch to manual mode.
[0031] The mechanical features of the machine are similar to the
current state of the art strapping heads available on the market
with the following differences:
[0032] 1. Quick release Jaw stack: There is no need to strip the
machine in order to replace the jaw stack and anvil. This can now
be completed with the strapping head in place on the compactor or
bundling machine.
[0033] 2. Removal of oil from the coil and bars being strapped.
[0034] 3. Reduced maintenance and operator intervention.
[0035] 4. Jaw design for wear compensation.
[0036] The machine functions as follows:
[0037] The master movement controller 1 located on the strap pinch
axis holds the overall program sequence. The master movement
controller 1 then handshakes with the other movement controllers 6,
10, and 15 in the desired sequence. Each movement controller 6, 10,
and 15 contains the parameters needed for its move or operation and
then handshakes back to the master controller 1 to confirm the
moves completeness or error function. If there is an error function
the master controller 1 resets the sequence and it is tried again.
If this fails the master controller 1 switches to manual mode and
alerts the external operating system of the machine it is
incorporated into that manual moves are required.
[0038] At the start of a cycle a ready signal given to an external
operating system and a remote I/O is given to start sequence from
the external system.
[0039] The pinch then is closed by the master movement controller 1
and the strap is fed around the external guide track by the feed
unit movement controller 4. The length of strap is determined by
step counts or en external switch dependent on the application.
[0040] As the strap is fed the main crimp axis movement controller
15 closes the crimp jaws 50% to aid in guiding the strap by the
movement controller 15. On completion of strap feeding the clamp is
closed via the movement controller 10. The strap is then tensioned
pulled in reverse until controller 6 attached to the lower roller 8
detects a stall condition at full torque or a specified torque
value.
[0041] At this stage the main crimp and cut movement controller is
actuated by the controller 15. This action then creates the crimp
and cuts the strap from the main reel, in that sequence but from
the same axis. At this time the tension motor 5 stops pulling the
strap as the crimp movement controller tells the movement
controller 6 at the pinch rolls 7 and 8 to stop. Once the tension
motor 6 stops, the secondary crimps are actuated by the movement
controller 22.
[0042] On completion of this action all movement controllers 6, 10,
and 15 return to the home position, but not the master controller
1. Instead the master controller 1 then relays a signal to the
external system that the process is complete and any other external
actions can be completed as required.
[0043] This sequence of operations is different from the current
state of the art hydraulic heads as they signal a dumb relay
solenoid and rely on a dumb proximity switch to signal a process is
complete. Instead, the head according to the invention continuously
monitors position, torque, and current and thus can be deliver
real-time feed back to the master controller 1 as needed to ensure
the process is completed correctly without the use of an external
PLC system or extra external hardware.
[0044] Thus this system with its intelligent platform or
architecture, is fully adjustably configurable without mechanical
intervention or disassembly. It can run without the use of external
PLC controllers, and the head is interchangeable with any platform.
The head can compensate for jaw wear without mechanical
intervention. It can also vary binding strength based on
indentation crimp depth our competitors can not it is a fixed
variable for each crimp.
[0045] The operation cycle for the machine resides in the machine
itself so there is no need for an external PLC to control the head
and or heads if working in unison. Each movement controller informs
the next that its task is complete within the head without the need
for external I/O or PLC interaction in the process. Furthermore the
machine process can be changed without manual intervention or
physically altering the machine by shimming or adjusting mechanical
parts. The removal of all hydraulic and pneumatic consumable media
from the working area greatly simplifies its hookup and servicing.
Furthermore the machine can be adapted into any existing strapping
process or machine without having to re-configure the existing
control architecture or PLC logic.
[0046] A final advantage of the inventive system is reduced energy
consumption as no hydraulic media power pack required to feed the
heads. In fact, the head consume on average 1.5 kW total power
during operation compared to 5-10 kW for the hydraulic prior-art
equivalents.
* * * * *