U.S. patent application number 15/132600 was filed with the patent office on 2016-10-20 for method to automatically control thread tension.
The applicant listed for this patent is Gammill, Inc.. Invention is credited to John Ray Buse, Daniel Lee Elliott.
Application Number | 20160305054 15/132600 |
Document ID | / |
Family ID | 57129179 |
Filed Date | 2016-10-20 |
United States Patent
Application |
20160305054 |
Kind Code |
A1 |
Elliott; Daniel Lee ; et
al. |
October 20, 2016 |
METHOD TO AUTOMATICALLY CONTROL THREAD TENSION
Abstract
The present invention relates to automatically controlling the
tension of thread sewn while operating a sewing machine The system
for controlling the tension of thread being used includes a wheel
or other gripping mechanism that is in mechanical communication
with a motor. When voltage and/or current is provided to the motor
via electronic circuitry, the motor "pulls" on the thread with the
desired force in a direction opposite to how the thread normally
flows. The voltage and/or current delivered to the motor may be
adjusted by a user. When the motor pulls on a thread to provide
tension, the tension may be maintained independently of the sliding
friction of the thread. As such, the tension is very accurate and
repeatable, and provides for a tension that cannot be achieved with
currently existing sewing machines.
Inventors: |
Elliott; Daniel Lee; (West
Plains, MO) ; Buse; John Ray; (Houston, MO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Gammill, Inc. |
West Plains |
MO |
US |
|
|
Family ID: |
57129179 |
Appl. No.: |
15/132600 |
Filed: |
April 19, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62150054 |
Apr 20, 2015 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D05B 47/04 20130101 |
International
Class: |
D05B 47/04 20060101
D05B047/04 |
Claims
1. A system for automatically controlling thread tension of thread
flowing toward material to be stitched, the system comprising: a
wheel for gripping thread to be used during sewing; a motor for
controlling the operation of the wheel; a shaft connecting the
wheel to the motor such that when the motor is activated, the shaft
and wheel are rotated and tension is applied to thread on the wheel
in a direction opposite of the material to be stitched; and an
input device in communication with the motor for applying at least
one of a voltage and current which is proportional to a desired
amount of tension to the motor.
2. The system of claim 1, wherein the motor is one of a: DC servo,
BLDC, Stepper, AC, Pneumatic, or Hydraulic motor.
3. The system of claim 1, wherein the system further includes an
encoder in electronic communication with the motor for measuring at
least one of: the amount of thread and thread velocity.
4. The system of claim 3, wherein the encoder acts as a thread
break detection device.
5. The system of claim 1, wherein the input device is one of a:
tablet computer, personal computer, and a knob.
6. A method for automatically controlling thread tension of thread
flowing toward material to be stitched, the method comprising the
steps of: providing a selection of a tension, that corresponds to
at least one of a voltage and current, into an input device;
transmitting at least one of said voltage and current to a motor
via electronic circuitry; said motor pulling on a shaft in
mechanical connection with a wheel for gripping thread, wherein
said wheel is pulled by said shaft in a direction opposite of
material to be stitched, the at least one of the voltage and
current causing said motor to create the selected tension in the
thread; and said one of a voltage and current delivered being
adjustable via said input device.
7. The method of claim 6, wherein the motor is one of a: DC servo,
BLDC, Stepper, AC, Pneumatic, or Hydraulic motor.
8. The method of claim 6, further comprising the step of measuring
at least one of: the amount of thread and thread velocity via an
encoder in electronic communication with the motor.
9. The method of claim 8, wherein the encoder is also able to
detect a break in thread.
10. The method of claim 6, wherein the input device is one of a:
tablet computer, personal computer, and a knob.
11. A system for automatically controlling thread tension of thread
flowing toward material to be stitched, the system comprising: a
motor; a shaft attached to said motor; a wheel for gripping thread
to be used during sewing also attached to said shaft, wherein when
the motor is activated, the shaft and wheel are rotated and tension
is applied to thread on the wheel in a direction opposite to
material to be stitched; and an input device connected to the motor
for applying at least one of a voltage and current which is
proportional to a desired amount of tension to the motor.
12. The system of claim 11, wherein the motor is one of a: DC
servo, BLDC, Stepper, AC, Pneumatic, or Hydraulic motor.
13. The system of claim 11, wherein the system further includes an
encoder in electronic communication with the motor for measuring at
least one of: the amount of thread and thread velocity.
14. The system of claim 13, wherein the encoder acts as a thread
break detection device.
15. The system of claim 11, wherein the input device is one of a:
tablet computer, personal computer, and a knob.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 62/150,054, filed Apr. 20, 2015, which is hereby
incorporated by reference in its entirety.
BACKGROUND OF INVENTION
[0002] Many machines have been developed and are commercially
available for sewing quilts, comforters, and other similar textile
goods. A key component to the quality of stitching the
aforementioned goods is the tension of the thread being sewn. As a
result, a critical part to every sewing machine is a tension device
for controlling the thread tension.
[0003] Typically the method for adjusting thread tension involves
two disks. An example of such a tension control device is shown and
described in U.S. Pat. No. 6,595,150 to Yamazaki. The disks are
typically placed over a threaded post and held in place by a spring
and a knob that are threaded onto the post and held in place by a
nut. The thread is passed between the disks, usually wrapping once
around the post. When the position of the knob is adjusted, the
amount of spring force exerted onto the disks may then be adjusted.
This change in spring force results in a different amount of
sliding friction on the thread. It is this friction that creates
the tension in the thread being sewn.
[0004] Recently, other ways have been devised to remove the manual
spring and knob and to replace the manual spring and knob with an
"automatic" mechanism. One such automatic mechanism utilizes a
pneumatic cylinder to exert the force onto the disk rather than the
spring. By changing the air pressure of the pneumatic cylinder, the
force on the disk changes, and thus the thread tension changes. Yet
another method has been to replace the threaded post and nut with a
ball screw or jack screw arrangement attached to a motor. By using
the motor to turn the screw, a collar or other means may be moved
to apply more or less force onto the spring, thus changing the
tension.
[0005] The aforementioned existing methods all have at least one
significant drawback. The above described methods rely on the
sliding friction of the thread. Thread sliding friction can vary
greatly depending on the thread quality and/or composition. If a
thread is particularly slick, it may not be possible to deliver
sufficient tension to produce quality stitching. If a thread is
very coarse, too much tension may be delivered.
SUMMARY OF INVENTION
[0006] The present invention provides for a device and method for
digitally controlling thread tension as thread is sewn. The device
may operate by using a servo motor or other motor type to control
the thread's tension. The specific method in which the device
operates, as well as its various components, are described in
greater detail below.
[0007] The method and device provide a number of benefits over the
current state of the art described above. For example, with the
improved device/method subject of this invention, thread tension
may be maintained independently of various sliding frictions of the
thread. As such, an accurate and repeatable tension may be
generated that cannot be achieved with any other system. Moreover,
digital control allows for an extremely high adjustment resolution
of the thread tension. Such resolution is limited only by the
resolution of the control circuitry contained within the device.
For example, 32 bit resolution (2,147,483,647 possible adjustment
steps) or greater resolution may be possible when the present
invention is in use.
[0008] Moreover, the digital control of the present invention may
allow for nearly instantaneous changes in thread tension. As a
result, major changes in the thread tension during different parts
of a stitch cycle may be made in order to optimize the final thread
appearance in the resulting work when the sewing process is
finished. Again, no existing method allows for such rapid changes
in thread tension.
[0009] The present invention also may provide a much more reliable
device and method than the other mechanisms described above as the
other mechanisms include screws, springs, and other moving parts
that may be subject to frequent mechanical error and thus often
need to be repaired. Moreover, the present invention may include
the added benefit of being able detect a break in thread during the
sewing process.
[0010] A wheel or some other method for "gripping" the thread may
be utilized when the device is in use. The thread may be wrapped
around such a wheel that is designed to grip thread. Alternative
embodiments for doing so may include passing thread between two
rollers.
[0011] The wheel or other mechanism for gripping the thread may be
attached and in mechanical communication with a motor. The motor
may be of nearly any type, for example: DC, BLDC, Stepper, AC,
Pneumatic, or Hydraulic, just to name a few. The preferred
embodiment uses a DC servo motor.
[0012] When in use, a voltage and/or current that is proportional
to the amount of tension required may be delivered to the motor via
a user input device. The user input device may communicate or
otherwise transmit the voltage and/or current to the motor via
electronic circuitry. This causes the motor to "pull" on the thread
with the desired force in the direction opposite of how the thread
normally flows (e.g., toward the needle, where stitching takes
place). The voltage and/or current may be adjusted by a user to
obtain the desired tension. The tension may be a set value, or the
tension may be continually changed during different parts of a
stitch cycle.
[0013] Desired tension and other adjustments may be user-adjustable
through the use of a knob, keypad, touchscreen or other user input
device. The preferred embodiment uses a tablet or PC computer
interface.
[0014] In the preferred embodiment, the motor may be attached to
and in communication with, an encoder or other positioning device.
When an encoder is attached to and in communication with the motor,
the encoder allows the amount and velocity of the thread being sewn
to be measured. Closed loop control schemes may be utilized to
ensure that the thread tension is being adjusted at the desired
force or velocity. The encoder may further allow the device to act
as a thread break detection device. Greater detail about the
present invention is provided in the detailed description of the
invention below.
DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0015] In the accompanying drawings, which form a part of the
specification and are to be read in conjunction therewith in which
like reference numerals are used to indicate like or similar parts
in the various views:
[0016] FIG. 1 is a top perspective view of the thread tension
control system according to the teachings of the present
invention;
[0017] FIG. 2 is an exploded perspective view of the thread tension
control system of FIG. 1; and
[0018] FIG. 3 is a bottom perspective view of the thread tension
control system of FIGS. 1 and 2.
DETAILED DESCRIPTION OF THE INVENTION
[0019] FIG. 1 illustrates a top perspective view of a thread
tension control system 1 for controlling the tension of thread used
in the sewing process, hereinafter referred to as control system 1.
Control system 1 may be placed in a number of locations on a sewing
or quilting machine and secured thereto, in a manner well
understood in the art. In the preferred embodiment, control system
1 is positioned and attached to the top of a quilting or sewing
machine (not illustrated). Control system 1 may be attached to a
sewing machine by means of a bracketing device, screw mechanism or
other foreseeable fastening member.
[0020] Control system 1 includes a wheel 5, as illustrated in FIGS.
1 and 2, which may be used to grip thread that preferably is
stitched during the sewing process. As will be described below, in
the preferred embodiment, when a sewing machine is in use, thread
is wrapped around wheel 5 in order to grip the thread. Alternative
embodiments to replace wheel 5 in control system 1 for gripping
thread may include passing the thread between two rollers, around a
spool, or other means that would be foreseeable to those skilled in
the art.
[0021] As shown in greater detail in FIG. 2, wheel 5 of control
device 1 may be attached to and in mechanical communication with a
motor 10. In the preferred embodiment motor 10 is a DC servo motor,
but in alternative embodiments motor 10 may be of nearly any type
able to perform the functions described herein. For example, in
alternative embodiments, motor 10 may be Brushless DC (BLDC),
Stepper, AC, Pneumatic, or Hydraulic. Also as shown in FIG. 2,
wheel 5 and motor 10 are connected by a shaft 15. When motor 10 is
in operation, as described below, it causes shaft 15 to rotate.
When shaft 15 rotates, wheel 5 may also rotate such that a tension
is applied to a thread. Other foreseeable members may be utilized
as an alternative to shaft 15 to facilitate the rotation of wheel 5
such that it applies tension to the thread being sewn. In the
illustrated embodiment, wheel 5 is affixed to motor 10 using a
screw 20, washer 25, and nut 30 in a manner used widely in the art.
Other means or members for attaching wheel 5 to motor 10 will also
be appreciated by those skilled in the art.
[0022] As shown in greater detail in FIG. 2, control system 1
further includes a circuit board 45 comprising a plurality of
electronic components. Circuit board 45 may be of the type commonly
used in electronic applications. USB port 50 is also illustrated in
FIG. 2. USB port 50 is shown in FIG. 1 when control system 1 is in
its closed configuration, the configuration in which control system
appears when in use. In the preferred embodiment, USB port 50
provides power to control system 1 in a manner well understood and
known in the art.
[0023] Circuit board 45 may be in electronic communication with
motor 10 by way of electronic circuitry 55. Electronic circuitry 55
is shown in FIG. 2 in exploded form. Electronic circuitry 55 is in
electronic connection with motor 10 at one end and with circuit
board 45 at its other end, as shown in FIG. 3.
[0024] Control system 1 may also include a user input device (not
illustrated). The input device communicates with circuit board 45
via a Bluetooth connection, wireless connection, or other
foreseeable means of receiving instructions and other communication
from a user. In the preferred embodiment, the user uses a tablet or
other PC computer interface in order to adjust the various controls
of control system 1. In the alternative, the input device may be a
knob, keypad, or touchscreen, though the aforementioned examples
are exemplary only and are non-limiting.
[0025] Motor 10 is also preferably attached and in electronic
communication with an encoder or other positioning device. The
encoder (not illustrated) allows the amount of thread and/or thread
velocity to be measured. In at least one embodiment, the encoder
also allows control system 1 to act as a thread break detection
device.
[0026] In operation, a user may use the user input device, for
example a tablet, in order to adjust the amount of tension desired
for the thread. When doing so, a voltage and/or current which is
proportional to the amount of tension desired may be delivered to
motor 10 by way of electronic circuitry 55. Subsequently motor 10
instructs shaft 15 to rotate wheel 5 and thus pull on the thread
which wheel 5 is gripping with the input force in the direction
opposite to which the thread normally flows (e.g., toward a needle,
where stitching takes place). In alternative embodiments, the
thread is passed between rollers or otherwise wrapped around a
support, such as a post. Other foreseeable thread gripping members
will be appreciated by those skilled in the art and are completed
herein.
[0027] During the sewing process, when the thread is gripped by
wheel 5 and tension is applied by motor 10, tension may be
maintained independently of the thread's sliding friction. Such
sliding frictions may vary greatly among thread type depending on
characteristics such as thread material, thread quality, and thread
thickness. Because the tension is not dependent of thread sliding
friction, control system 1 may achieve accurate and repeatable
thread tensions.
[0028] The user input device may also be used during the tension
application process to adjust the voltage and/or current provided
in order to obtain the desired tension. The tension provided may be
a set value, or the tension may continually change during different
parts of a stitching cycle. Closed loop control schemes may be
utilized in order to provide the desired thread tension. The
changes in thread tension that may be desired are preferably nearly
instantaneous due to the electronic method utilized.
[0029] Because the thread tension is digitally controlled by a user
input device in electronic communication with control system 1,
high resolution and repeatable thread tensions are possible. For
example, the thread tension may be adjustable to a limit that is
limited only by the resolution of circuit board 45 associated with
control system 1. For example, 32 bit resolution (2,147,483,647
adjustment steps) or higher is a possible maximum resolution for
thread tension adjustment.
[0030] Moreover, in the preferred embodiment, the encoder may
measure the amount of thread and/or thread velocity. As such, the
encoder may allow control system 1 to act as a thread break
detection device. For example, if the thread tension is zero, the
encoder may be able to determine that the thread has broken, and
that the control device 1 will shut down the sewing process until
the thread is repaired and/or replaced.
[0031] From the foregoing, it will be seen that this invention is
one well adapted to attain all the ends and objects hereinabove set
forth together with other advantages which are obvious and which
are inherent to the structure. It will be understood that certain
features and sub combinations are of utility and may be employed
without reference to other features and sub combinations. This is
contemplated by and is within the scope of the claims Since many
possible embodiments of the invention may be made without departing
from the scope thereof, it is also to be understood that all
matters herein set forth or shown in the accompanying drawings are
to be interpreted as illustrative and not limiting.
[0032] The constructions described above and illustrated in the
drawings are presented by way of example only and are not intended
to limit the concepts and principles of the present invention.
Thus, there has been shown and described several embodiments of a
novel invention. As is evident from the foregoing description,
certain aspects of the present invention are not limited by the
particular details of the examples illustrated herein, and it is
therefore contemplated that other modifications and applications,
or equivalents thereof, will occur to those skilled in the art. The
terms "having" and "including" and similar terms as used in the
foregoing specification are used in the sense of "optional" or "may
include" and not as "required". Many changes, modifications,
variations and other uses and applications of the present
construction will, however, become apparent to those skilled in the
art after considering the specification and the accompanying
drawings. All such changes, modifications, variations and other
uses and applications which do not depart from the spirit and scope
of the invention are deemed to be covered by the invention which is
limited only by the claims which follow.
* * * * *