U.S. patent application number 11/291651 was filed with the patent office on 2006-06-01 for stitch regulator for a sewing machine.
Invention is credited to Christopher A. Boyd, Mark A. Carlin, Thomas A. Pfeifer.
Application Number | 20060112866 11/291651 |
Document ID | / |
Family ID | 36566220 |
Filed Date | 2006-06-01 |
United States Patent
Application |
20060112866 |
Kind Code |
A1 |
Pfeifer; Thomas A. ; et
al. |
June 1, 2006 |
Stitch regulator for a sewing machine
Abstract
A stitch regulator (50) for use with a sewing machine (34)
transported by a moveable platform (26) includes a housing (52)
configured to be coupled to one of the sewing machine (34) and the
moveable platform (26). An X-axis rate sensor (92) and a Y-axis
rate sensor (96) determine movement of the sewing machine (34) on
the moveable platform (26). A microcontroller (118) is contained in
the housing (52) and is in communication with the sensors (92, 96).
The microcontroller (118) generates a motor control signal (126) in
response to the movement of the sewing machine (34) for input into
a motor control input port (88) of the sewing machine (34).
Inventors: |
Pfeifer; Thomas A.;
(Glendale, AZ) ; Carlin; Mark A.; (Gilbert,
AZ) ; Boyd; Christopher A.; (Goodyear, AZ) |
Correspondence
Address: |
MESCHKOW & GRESHAM, P.L.C.
5727 NORTH SEVENTH STREET, SUITE 409
PHOENIX
AZ
85014
US
|
Family ID: |
36566220 |
Appl. No.: |
11/291651 |
Filed: |
November 30, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60632563 |
Dec 1, 2004 |
|
|
|
Current U.S.
Class: |
112/117 |
Current CPC
Class: |
D05B 11/00 20130101;
D05B 19/12 20130101; D05B 69/14 20130101 |
Class at
Publication: |
112/117 |
International
Class: |
D05B 11/00 20060101
D05B011/00 |
Claims
1. A stitch regulator for use with a sewing machine transported by
a moveable platform, said sewing machine having a motor control
input port, and said stitch regulator comprising: a housing
configured to be coupled to one of said sewing machine and said
moveable platform; a sensor adapted for communication with said
sewing machine for determining movement of said sewing machine on
said moveable platform; and a microcontroller contained in said
housing and in communication with said sensor, said microcontroller
generating a motor control signal in response to said movement of
said sewing machine, for input into said motor control input
port.
2. A stitch regulator as claimed in claim 1 further comprising a
handle extending from a facing plate of said housing for enabling
manual movement of said sewing machine on said moveable platform
relative to a piece of fabric.
3. A stitch regulator as claimed in claim 2 wherein said handle is
a first handle, and said stitch regulator further comprises a
second handle extending from said facing plate and spaced apart
from said first handle.
4. A stitch regulator as claimed in claim 2 further comprising a
run switch mounted on said handle and in electrical communication
with said microcontroller, and actuation of said run switch enables
provision of said motor control signal.
5. A stitch regulator as claimed in claim 1 wherein said housing
comprises an angled facing plate.
6. A stitch regulator as claimed in claim 5 further comprising
keypad controls mounted on said angled facing plate and in
electrical communication with said microcontroller.
7. A stitch regulator as claimed in claim 1 wherein said housing
comprises: a first section having a first pair of longitudinal
edges; and a second section having a second pair of longitudinal
edges that form a snap-fit connection with said first pair of
longitudinal edges.
8. A stitch regulator as claimed in claim 1 wherein said housing is
in the form of a triangular prism.
9. A stitch regulator as claimed in claim 1 wherein said sensor
comprises: a first sensor for determining velocity of said sewing
machine in a first direction; and a second sensor for determining
said velocity of said sewing machine in a second direction, said
second direction being orthogonal to said first direction.
10. A stitch regulator as claimed in claim 1 wherein said sewing
machine includes a motor exhibiting a motor characteristic, and
said microcontroller generates said motor control signal in
response to said motor characteristic in combination with said
movement of said sewing machine.
11. A stitch regulator as claimed in claim 10 wherein said stitch
regulator is usable with a second sewing machine, said second
sewing machine includes a second motor exhibiting a second motor
characteristic, and said microcontroller generates a second motor
control signal in response to said movement of said second sewing
machine in combination with said second motor characteristic when
said stitch regulator is in use with said second sewing
machine.
12. A stitch regulator as claimed in claim 1 further comprising an
input element in communication with said microcontroller, said
microcontroller generating said motor control signal in response to
a command entered at said input element in combination with said
movement of said sewing machine.
13. A stitch regulator as claimed in claim 12 wherein said command
comprises a desired stitch density, and said motor control signal
is configured to regulate a speed of a motor of said sewing machine
to achieve said desired stitch density.
14. A stitch regulator as claimed in claim 1 further comprising: an
outlet configured for communication with said motor control input
port; and at least two potentiometers interposed between said
microcontroller and said outlet, said at least two digital
potentiometers being selectively controlled by said microcontroller
to generate said motor control signal.
15. A stitch regulator as claimed in claim 1 further comprising: an
outlet configured for communication with said motor control input
port; and a matrix switch interposed between said microcontroller
and said outlet for receiving said motor control signal and
directing said motor control signal to an output bus of said matrix
switch selected by said microcontroller.
16. A stitch regulator as claimed in claim 1 wherein said sewing
machine includes a thread cut control port, and said stitch
regulator further comprises a thread cut control element contained
in said housing and controlled by said microcontroller for
generating a thread cut signal for input into said thread cut
control port.
17. A stitch regulator for use with a sewing machine transported by
a moveable platform, said sewing machine having a motor control
input port, and said stitch regulator comprising: a housing
configured to be coupled to one of said sewing machine and said
moveable platform, said housing having an angled facing plate; a
handle extending from said facing plate for enabling manual
movement of said sewing machine on said moveable platform relative
to a piece of fabric; a sensor adapted for communication with said
sewing machine for determining movement of said sewing machine on
said moveable platform; a microcontroller contained in said housing
and in communication with said sensor; and keypad controls mounted
on said angled facing plate and in electrical communication with
said microcontroller, said microcontroller generating a motor
control signal in response to a command entered at said keypad
controls in combination with said movement of said sewing machine
for input into said motor control input port.
18. A stitch regulator as claimed in claim 17 wherein said handle
is a first handle, and said stitch regulator further comprises a
second handle extending from said facing plate and spaced apart
from said first handle.
19. A stitch regulator as claimed in claim 17 wherein said housing
further comprises a body section having a first pair of
longitudinal edges that form a snap-fit connection with a second
pair of longitudinal edges on said facing plate.
20. A stitch regulator as claimed in claim 17 wherein said housing
is in the form of a triangular prism.
21. A stitch regulator for use with a sewing machine transported by
a moveable platform, said sewing machine including a motor
exhibiting a motor characteristic, and a motor control input port
in communication with said motor, and said stitch regulator
comprising: a housing configured to be coupled to one of said
sewing machine and said moveable platform; a sensor adapted for
communication with said sewing machine for determining movement of
said sewing machine on said moveable platform; a microcontroller
contained in said housing and in communication with said sensor; an
outlet configured for communication with said motor control input
port; and at least two potentiometers interposed between said
microcontroller and said outlet, said at least two digital
potentiometers being selectively controlled by said microcontroller
to generate a motor control signal in response to said motor
characteristic in combination with movement of said sewing machine
for input into said motor control input port.
22. A stitch regulator as claimed in claim 21 wherein said stitch
regulator is usable with a second sewing machine, said second
sewing machine includes a second motor exhibiting a second motor
characteristic, and said microcontroller selectively controls said
at least two digital potentiometers to generate a second motor
control signal in response to said second motor characteristic in
combination with movement of said second sewing machine when said
stitch regulator is in use with said second sewing machine.
23. A stitch regulator as claimed in claim 21 further comprising a
matrix switch interposed between said at least two potentiometers
and said outlet for receiving said motor control signal and
directing said motor control signal to an output bus of said matrix
switch selected by said microcontroller.
Description
RELATED INVENTION
[0001] The present invention claims priority under 35 U.S.C.
.sctn.119(e) to: "Speed Control for a Sewing Machine," U.S.
Provisional Patent Application Ser. No. 60/632,563, filed 1 Dec.
2004, which is incorporated by reference herein.
TECHNICAL FIELD OF THE INVENTION
[0002] The present invention relates to the field of sewing
machines. More specifically, the present invention relates to a
stitch regulator for use with a sewing machine transported by a
moveable platform relative to a piece of fabric.
BACKGROUND OF THE INVENTION
[0003] Quilting has been in practice for many years, initially for
utilitarian purposes, and more recently as a way of artistic
expression. The continued popularity of the craft has lead to the
development of modern textiles, equipment, and labor-saving sewing
devices.
[0004] Quilting typically entails sewing two layers of cloth with a
layer of insulating batting in between, thus forming a quilt.
Quilts may be formed in a variety of shapes and styles that are
variously used to cover beds, to decorate walls, used as lap
cloths, and so forth. Designs and patterns are typically sewn, or
stitched, into a quilt by hand or with a sewing machine to secure
the two layers of cloth and the layer of batting together. Complex
designs and patterns are often hand-stitched by a skilled
craftsperson. However, such hand-stitching can be too time
consuming for a skilled craftsperson, and may be too challenging
for those who are not as skilled at hand-stitching. In addition,
hand-stitching may be difficult or even impossible for those with
limited mobility of their fingers, such as for an individual who
has arthritis. Thus, some individuals utilize machine sewing
techniques to stitch a quilt.
[0005] Unfortunately, however, when using a sewing machine, the
hobbyist must manipulate an unwieldy, multilayered fabric sandwich
under the needle bar of the sewing machine. Such manipulation can
be difficult, and cause puckering and stitching errors.
Accordingly, market demand has lead to the development of quilting
devices for holding the fabric to be quilted and moving the sewing
machine relative to the fabric. A quilting table is one such
quilting device.
[0006] FIG. 1 shows a front perspective view of a prior art
quilting table 20. Quilting table 20 generally includes a frame 22,
a fabric support system 24 for holding the fabric to be quilted, a
platform assembly 26, and an overhead shelf 28. Platform assembly
26 is moveable relative to a longitudinal dimension, or X-axis 30,
and a transverse dimension, or Y-axis 32, of frame 22. In general,
platform assembly 26 supports and transports a conventional,
household sewing machine 34, for moving sewing machine 34 relative
to the fabric.
[0007] Frame 22 generally holds one or more payout rollers 36, onto
which fabric is rolled, and a take-up roller 38. Take-up roller 38
is typically directed through the throat of sewing machine 34 so
that fabric suspended between payout rollers 36 and take-up roller
38 can be passed under the needle bar of sewing machine 34 for
machine stitching. Platform assembly 26 typically includes two
carriages, one sitting upon the other. One carriage moves in the
longitudinal direction, i.e., along X-axis 30, and the other
carriage moves upon the first carriage in the transverse direction,
i.e., along Y-axis 32. Platform assembly 26 can then be manually
manipulated by the user to impart a stitch pattern onto the
fabric.
[0008] A handle 40 may be coupled to platform assembly 26 on a
needle side 42 of quilting table 20 for manually translating the
carriages of platform assembly 26 longitudinally and transversely
relative to X-axis 30 and Y-axis 32. In such a configuration, an
individual may be located at and operate sewing machine 34 from
needle side 42 of quilting table 20. As such, the fabric and needle
of sewing machine 34 are readily visible to the individual as the
fabric is being stitched. In order to facilitate operation of
sewing machine 34 from needle side 42 of quilting table 20, handle
40 may include the capability to both turn off and turn on sewing
machine 34. In addition, handle 40 may include the capability to
adjust an operational speed of sewing machine 34.
[0009] Stitch regulators that provide the capability to both turn
off and turn on, as well as to adjust the operational speed of, a
sewing machine are known for utilization with a quilting table. One
prior art stitch regulator includes a computer board located inside
of the sewing machine and having a controller mounted thereon. The
prior art stitch regulator further includes front and rear control
panels and handle switches, two track sensors, and a needle
position sensor. The stitch regulator is driven by software
embedded inside a microchip. The track sensors measure the changing
location of the needle as the sewing machine is moved on the
platform assembly, and the needle position sensor recognizes if the
needle is up or down. The stitching mode and other commands are set
on the control panel. The controller uses the needle location data,
the needle up/down data, and the entered stitching mode and other
commands to determine when a stitch should be completed and sends a
motor control signal to the sewing machine motor.
[0010] While such a stitch regulator can be useful for an operator,
prior art stitch regulators suffer from a number of problems. For
example, the stitch regulator discussed above requires installation
of a portion of the device inside of the sewing machine. Therefore,
it cannot be readily implemented with a number of sewing machines
without invasive and costly modification to the sewing
machines.
[0011] A further problem with prior art stitch regulators is that
current stitch regulator systems are not necessarily accurate
regarding stitch regulation across a variety of machine types. This
inaccuracy occurs because the actual motor speed of a particular
motor is affected by the characteristics of that motor.
Consequently, a motor control signal input to a motor of one type
of sewing machine might not cause the motor to operate at the same
speed as when the motor control signal is input to a motor of a
different type of machine. Therefore, stitch regulation could be
inconsistent across a variety of machine types.
[0012] Another deficiency in the current stitch regulator systems
is that the motor speed for each type of machine is not necessarily
linear with the motor control signal. That is, sending a motor
control signal that is twice the motor speed of a first motor
control signal does not necessarily make the sewing machine motor
run twice as fast as the first motor control signal. This situation
can further lead to inconsistent stitch regulation at various
operational speeds of a sewing machine.
SUMMARY OF THE INVENTION
[0013] Accordingly, it is an advantage of the present invention
that a stitch regulator for use with sewing machine transported by
a moveable platform is provided.
[0014] It is another advantage of the present invention that a
stitch regulator is provided that yields consistent stitch
regulation across a variety of sewing machine types.
[0015] Another advantage of the present invention is that a stitch
regulator is provided that yields consistent stitch regulation
across a wide variety of motor speeds for a sewing machine.
[0016] Yet another advantage of the present invention is that a
stitch regulator is provided that is intuitive to utilize, is
located exterior to a sewing machine, and is cost effectively
manufactured.
[0017] The above and other advantages of the present invention are
carried out in one form by a stitch regulator for use with a sewing
machine transported by a moveable platform, the sewing machine
having a motor control input port. The stitch regulator includes a
housing configured to be coupled to one of the sewing machine and
the moveable platform, and a sensor adapted for communication with
the sewing machine for determining movement of the sewing machine
on the moveable platform. A microcontroller is contained in the
housing and is in communication with the sensor. The
microcontroller generates a motor control signal in response to the
movement of the sewing machine, for input into the motor control
input port.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] A more complete understanding of the present invention may
be derived by referring to the detailed description and claims when
considered in connection with the Figures, wherein like reference
numbers refer to similar items throughout the Figures, and:
[0019] FIG. 1 shows a front perspective view of a prior art
quilting table;
[0020] FIG. 2 shows a front perspective view of a stitch regulator
in accordance with a preferred embodiment of the present
invention;
[0021] FIG. 3 shows an exploded side view of a housing of the
stitch regulator;
[0022] FIG. 4 shows an exploded perspective view of a platform
assembly with a stitch regulator mountable thereon;
[0023] FIG. 5 shows a partial front view of the stitch regulator
illustrating keypad controls;
[0024] FIG. 6 shows a block diagram of the stitch regulator;
[0025] FIG. 7 shows a block diagram of a portion of the stitch
regulator;
[0026] FIG. 8 shows a graph typifying a motor characteristic for a
sewing machine;
[0027] FIG. 9 shows a flow chart of a stitch regulator operation
process; and
[0028] FIG. 10 shows a table of formulas executed within the stitch
regulator for determining a motor control signal for input into a
sewing machine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] The present invention provides a stitch regulator for use
with a sewing machine. Such a stitch regulator may be utilized for
controlling motor speed of a sewing machine mounted on a moveable
platform assembly, such as that utilized on quilting table 20 (FIG.
1).
[0030] Referring to FIGS. 2-4, FIG. 2 shows a front perspective
view of a stitch regulator 50 in accordance with a preferred
embodiment of the present invention. FIG. 3 shows an exploded side
view of a housing 52 of stitch regulator 50 (FIG. 2), and FIG. 4
shows an exploded perspective view of a platform assembly, such as
platform assembly 26, with stitch regulator 50 mountable thereon.
For clarity of the following discussion, stitch regulator 50 is
utilized in connection with platform assembly 26 and sewing machine
34 (FIG. 1). However, it will become readily apparent that stitch
regulator 50 is not limited for use with the particular platform
assembly 26 and sewing machine 34 discussed herein, but may instead
be adapted for use with a number of moveable platforms and sewing
machine types.
[0031] Stitch regulator 50 includes housing 52 configured to be
coupled to either of sewing machine 34 or platform assembly 26. In
this exemplary configuration, stitch regulator 50 may couple, or
bolt, to platform assembly 26. As mentioned above, platform
assembly 26 supports and transports sewing machine 34 (FIG. 1)
relative to X-axis 30 and Y-axis 32. Platform assembly 26 generally
includes a first carriage 54 and a second carriage 56.
[0032] First carriage 54 includes first wheels 58 configured to
engage with rails on frame 22 (FIG. 2) that allow movement of
platform assembly 26 relative to X-axis 30. Second carriage 56
includes second wheels 60 arranged perpendicular to first wheels 58
of first carriage 54. Second wheels 60 engage with opposing rails
62 of first carriage 54 and allow movement of platform assembly 26
relative to Y-axis 32. Sewing machine 34 (FIG. 1) is seated on a
machine platform 64 that couples with second wheels 60 via carriage
supports 66. A support structure 68 is coupled to machine platform
64. Support structure 68 includes a pair of uprights 70 and a
framework 72. Stitch regulator 50 is mountable to framework 72.
[0033] Housing 52 of stitch regulator 50 includes a first section
in the form of an angled facing plate 74 and a second section, or a
rear section 76. Angled facing plate 74 includes a first pair of
longitudinal edges 75, and rear section 76 includes a second pair
of longitudinal edges 77. In a preferred embodiment, angled facing
plate 74 and rear section 76 are manufactured utilizing an aluminum
extrusion process for cost effective fabrication. Second pair of
longitudinal edges 77 forms a snap-fit connection with first pair
of longitudinal edges 75 for ease of assembly.
[0034] Following assembly, housing 52 generally takes the form of a
triangular prism. This shape facilitates the fit of stitch
regulator 50 with quilting table 20 (FIG. 1), and allows clear
visibility of the underlying head of sewing machine 34 and its
needle.
[0035] A first handle 78 and a second handle 80 extend from facing
plate 74. Keypad controls 82, in the form of a membrane keypad, are
mounted on facing plate 74, and a run switch 84 is mounted on first
handle 78. A first conductor 86 extends from stitch regulator 50
and couples to a motor control input port, conventionally known as
a foot pedal connection 88 (see FIG. 6) of sewing machine 34 (FIG.
1). Foot pedal connection 88 is, in turn, in communication with a
motor 89 (see FIG. 6), of sewing machine 34. A second conductor 90
extends from stitch regulator 50 and is in electrical communication
with a first sensor 92 coupled to first carriage 54. A third
conductor 94 extends from stitch regulator 50 and is in electrical
communication with a second sensor 96.
[0036] First and second sensors 92 and 96, respectively, may be
rotary optical encoders capable of measuring at least one direction
of movement (e.g. X-axis 30, Y-axis 32) of platform assembly 26 and
a velocity of movement. As such, first sensor 92 is referred to
hereinafter as an X-axis rate sensor 92. Similarly, second sensor
96 is referred to hereinafter as a Y-axis rate sensor 96. This
direction and velocity information can be provided to a
microcontroller (discussed below) of stitch regulator 50 for
providing position feedback of platform assembly 26, hence sewing
machine 34 (FIG. 1).
[0037] In general operation, a user selects the operational
parameters of stitch regulator 50 via keypad controls 82. The user
can then manually translate platform assembly 26 by holding onto
first and/or second handles 78 and 80, respectively, to move sewing
machine 34 relative to the underlying fabric held on quilting table
20 (FIG. 1). In an automatic mode, motor 89 of sewing machine 34
will run in response to the movement of platform assembly 26,
speeding up and slowing down in response to movement of platform
26, in order to yield consistent stitches.
[0038] FIG. 5 shows a partial front view of stitch regulator 50
illustrating keypad controls 82. In a preferred embodiment, keypad
controls 82 are formed utilizing a rugged, moisture resistant
membrane keypad that may optionally include tactile and audible
feedback. A single interconnecting flex cable extending from the
membrane keypad can interconnect with a microcontroller (discussed
below) of stitch regulator 50. Stitch regulator 50 further includes
a display 98 for presenting information pertaining to particular
operational modes selected by a user through actuation of keypad
controls 82.
[0039] Keypad controls 82 include a number of user selectable
buttons including a SETUP button 100, an up arrow button 102, a
down arrow button 104, a THREAD CUTTER button 106, a BOBBIN button
108, and a NEEDLE JOG button 110. Additional buttons on keypad
controls 82 include an AUTO mode button 112, a MANUAL mode button
114, and an OFF button 116. Those skilled in the art will recognize
that keypad controls 82 need not include all of the described
buttons but may alternatively include a subset of the
above-described buttons or additional buttons not described
herein.
[0040] Selection of the various buttons of keypad controls 82
causes the generation by stitch regulator 50 of a motor control
signal (discussed below). The motor control signal is input into
sewing machine 34 (FIG. 1) via foot pedal connection 88 (FIG. 6) to
appropriately drive motor 89 (FIG. 6) of sewing machine 34. The
specific function of each of these buttons will be described in
connection with the flowchart of FIG. 9.
[0041] FIG. 6 shows a block diagram of stitch regulator 50 for use
with sewing machine 34 (shown in ghost form). Stitch regulator 50
includes a microcontroller 118 having parameter inputs that include
X-axis rate sensor 92, Y-axis rate sensor 96, keypad controls 82,
and run switch 84. Microcontroller 118 has a first output line 119
in communication with at least one digital potentiometer 120. An
output of digital potentiometers 120 is in communication with a
matrix, or crosspoint, switch 122, and matrix switch 122 is in
communication with a run relay 124. A motor control signal 126 is
output from run relay 124 for input at foot pedal connection 88 via
first conductor 86.
[0042] Some sewing machines include a thread cut connection 130
that may be a connector port for a foot control. Through the
utilization of a foot control, the user can send a thread cut
signal to automatically sever threads, rather than through the
conventional process of moving a mass of fabric to manually cut
threads. As an alternative to the conventional foot control for
thread cutting, microcontroller 118 has a second output line 132 in
communication with a thread cutter relay 134. A thread cut signal
136 is output from thread cutter relay 134 for input at thread cut
connection 130 on sewing machine 34 via a conductor 138.
[0043] In addition to the above, microcontroller includes a third
output line 140 in communication with display 98, and a fourth
output line 142 in communication with a buzzer circuit 144 for
optional audible signaling to a user.
[0044] In a preferred embodiment, microcontroller 118 is an
integrated chip that contains all the components that make up a
controller, such as a central processing unit (CPU), memory for a
stitch regulator operation process 146 in the form of executable
code, memory for data such as a lookup table (LUT) 148, and one or
more timers. Microcontroller 118 executes stitch regulator
operation code 146 in response to inputs from, for example, X-axis
rate sensor 92, Y-axis rate sensor 94, keypad 82, and run switch
84, and selectively outputs motor control signal 126, thread cut
signal 136, associated text at display 98, and optional audio at
buzzer 144.
[0045] FIG. 7 shows a block diagram of a portion of the stitch
regulator 50. In particular, FIG. 7 provides additional details of
digital potentiometer 120, matrix switch 122, and run relay 124.
Stitch regulator 50 is adapted for use with a wide variety of
sewing machine types. To that end, various digital potentiometers
120 are utilized because different sewing machine types call for
very different values for maximum and minimum motor speed. As
shown, digital potentiometer 120 includes a one kilo ohm
potentiometer 147, a ten kilo ohm potentiometer 149, and a fifty
kilo ohm potentiometer 150. The specific potentiometers that make
up digital potentiometer 120 in this configuration are not a
limitation of the present invention, but can vary in accordance
with various designs, motor specifications, potentiometer
sensitivities, and the like.
[0046] Matrix switch 122 performs two functions. The first function
of matrix switch 122 is to connect the proper one (or more) of
potentiometers 147, 149, and 150 with foot pedal connection 88
(FIG. 6) on the different sewing machines. The second function of
matrix switch 122 is to provide the proper motor control signal 126
(FIG. 6) for motor off. Different machines call for different
control signals for motor off. For example, "machine A" may require
an open circuit for motor off, "machine B" may require a short for
motor off, and "machine C" may require a particular resistance,
such as one hundred forty seven kilo ohms for motor off.
[0047] The three terminals (TIP, RING, TERM3) form the electrical
interface of first conductor 86 for foot pedal connection 88 (FIG.
6) at sewing machine 34 (FIG. 6). Most sewing machines utilize mini
audio type two terminal jacks (ring/tip). However, others use three
terminals (tip/ring/term3). This particular jack is not a
limitation of the present invention. Those skilled in the art will
recognize that the present invention may be readily adapted to
accommodate other types of connection ports for other sewing
machines.
[0048] Run relay 124, when energized, connects foot pedal
connection 88 (FIG. 6) on sewing machine 34 (FIG. 6) to the correct
digital potentiometer 120, i.e., potentiometers 147, 149, and 150
through matrix switch 122. When de-energized, run relay 124
connects foot pedal connection 88 to a motor off signal, again
through matrix switch 122. Consequently, run relay 124 is used in
normal operation to provide motor control signal 126 to turn off
motor 89 (FIG. 6) and/or to control its speed. In addition, if
stitch regulator 50 loses power for any reason, run relay 124 will
be de-energized, resulting in a motor off signal.
[0049] FIG. 8 shows a graph 152 typifying a motor characteristic
154 for sewing machine 34 (FIG. 6). In this situation, motor
characteristic 154 represents an actual potentiometer value 156
needed to obtain a particular motor speed 158. In contrast, an
ideal linear relationship 160 of motor speed 158 versus
potentiometer value 156 is also illustrated in graph 152.
[0050] It has been discovered that the relationship between a
desired motor speed 158 and a potentiometer value 156 setting is
not necessarily linear for each machine type. Nor is this
relationship the same between various machines. Consequently, in
order to adapt stitch regulator 50 for use with a variety of sewing
machine types, each sewing machine is to be profiled, the results
of the profiling being utilized to generate lookup table 148 (FIG.
6).
[0051] Profiling is accomplished, for example, by measuring the
motor speed (e.g. revolutions per minute) of motor 89 (FIG. 6) as a
function of motor control resistance. There are several methods for
measuring motor speed. One such method calls for controlling a
motor input signal with a digital potentiometer, and measuring the
actual motor speed produced by the motor input signal to generate
graph 152. Consequently, lookup table 148 (FIG. 6) can be
constructed to include an actual potentiometer value 156 (i.e.,
resistance) needed for a particular machine type that produces a
desired motor speed 158. Alternatively, or in addition, lookup
table 148 can be constructed to include a potentiometer value
difference between the actual potentiometer value 156 needed and
the ideal potentiometer value typified by ideal linear relationship
160 for a desired motor speed 156.
[0052] Profiling can be performed for a multiplicity of machine
types, the results being stored in one or more lookup tables 148,
so that stitch regulator 50 can be implemented with a variety of
industrial, long arm, and home sewing machines.
[0053] FIG. 9 shows a flow chart of stitch regulator operation
process 146. Stitch regulator operation process 146 is executable
code recorded in a memory element of microcontroller 118.
[0054] Stitch regulator operation process 146 begins with a task
162. At task 162, stitch regulator 50 (FIG. 2) is initialized.
Initialization task 162 occurs at system power up of stitch
regulator 50. System power up may occur in response to actuation of
a separate power switch (not shown), in response to power up of
sewing machine 34 (FIG. 6), or when one of AUTO mode button 112
(FIG. 5) and MANUAL mode button 114 (FIG. 5) is pressed.
[0055] In response to task 162, a query task 166 is performed. At
query task 166, the system timer is monitored. When there is not a
system timer overflow condition, process 146 loops back to an input
of query task 166 to monitor for a system timer overflow condition.
However, when a system timer overflow condition is detected at
query task 166, process 146 proceeds to a task 168. Consequently,
query task 166 causes an overall process loop to be initiated. The
system timer may be set at fifty milliseconds. As such, the process
loop may run about every fifty milliseconds, the loop traversing
process 146.
[0056] At task 168, keypad controls 82 are scanned for keypad entry
by a user and debounced. In response to task 168, a series of query
tasks may be performed to determine the nature of any keypad entry
and a subsequent action executed by microcontroller 118 (FIG.
6).
[0057] For example, following task 168, a query task 170 is
performed. At query task 170, microcontroller 118 determines
whether AUTO mode button 112 (FIG. 5) has been selected. When AUTO
mode button 112 has been selected process control proceeds to a
task 172. At task 172, microcontroller 118 determines the velocity
of sewing machine 34 (FIG. 1) transported on platform assembly 26
(FIG. 4).
[0058] Following task 172, a task 174 is performed. At task 174,
microcontroller calculates motor control signal 126 (FIG. 6) for
automatic operation. In response to calculation task 174, process
146 proceeds to a task 176.
[0059] Referring to FIG. 10 in connection with tasks 174 and 176 of
process 146, FIG. 10 shows a table 176 of formulas executed by
microcontroller 118 for determining motor control signal 126 for
input into sewing machine 34 (FIG. 1).
[0060] Table 176 includes a first velocity formula 178 for
computing velocity of sewing machine 34 in a first direction, i.e.,
both directions of travel along X-axis 30 (FIG. 4), using input
from X-axis rate sensor 92 (FIG. 6). In addition, table 176
includes a second velocity formula 180 for computing velocity of
sewing machine 34 in a second direction, i.e., both directions of
travel along Y-axis 32 (FIG. 4), using input from Y-axis rate
sensor 96 (FIG. 6). These velocities result from movement, or lack
thereof, of sewing machine by a user holding onto first and/or
second handles 78 and 80, respectively (FIG. 3), and manually
manipulating sewing machine 34.
[0061] Next, the result of first and second velocity formulas are
utilized to compute a magnitude of the velocity of platform
assembly 26 and sewing machine 34, i.e. T(VEL), utilizing a
magnitude velocity formula 182. The magnitude of the velocity,
T(VEL), computed using magnitude velocity formula 182 is input into
a target motor speed formula 184. Target motor speed, in
revolutions per sec (RPS), is computed as a product of the
magnitude of the velocity of platform assembly 26 and a user
entered stitch density, in stitches per inch (SPI).
[0062] A digital potentiometer value 156 (FIG. 8) is computed as a
function of the target motor speed and a potentiometer value, or
correction factor, from lookup table 148 (FIG. 6) that relates to
the particular motor characteristic 154 (FIG. 8) for sewing machine
34. Digital potentiometer value 156 is computed using a
potentiometer value formula 186. The resulting potentiometer value
156, i.e., WIPER, can then be communicated from microcontroller 118
to digital potentiometers 120 (FIG. 6) to generate motor control
signal 126.
[0063] Referring back to process 146 (FIG. 9), in response to the
computation tasks 172 and 174, task 176 is performed. At task 176,
motor control signal 126 is generated. In this iteration of process
146, microcontroller 118 selectively controls potentiometers 120 to
set potentiometers 120 to potentiometer value 156 to generate motor
control signal 126. This motor control signal 126 is communicated
over first conductor 86 (FIG. 6) to foot pedal connection 88 (FIG.
6) via matrix switch 122 and the energization of run relay 124
(FIG. 6). Since process 146, under the control of the system
overflow timer at query task 166 is repeated approximately every
fifty milliseconds, stitch regulator 50 can readily respond to the
movement of sewing machine 34 in AUTO mode to produce the desired
stitch density by variously speeding up or slowing down motor 89
(FIG. 6) in response to a manually manipulated platform
velocity.
[0064] When in the AUTO mode, up and down arrow buttons 102 and
104, respectively (FIG. 6), can be utilized to adjust the desired
stitch density, i.e., the desired stitches per inch (SPI). Thus, in
AUTO mode, the motor speed is set based on the x/y velocity
measurement and a desired stitch density.
[0065] Referring back to query task 170, when microcontroller 118
determines that AUTO mode button 112 has not been selected, process
control proceeds to a query task 190. At query task 190,
microcontroller 118 determines whether MANUAL mode button 114 (FIG.
5) has been selected. When MANUAL mode button 114 has been selected
process control proceeds to a query task 192. At task 192,
microcontroller 118 determines whether run switch 84 (FIG. 2) is
closed. MANUAL mode allows a user to actuate motor 89 (FIG. 6) by
actuating run switch 84.
[0066] At task 192, when microcontroller 118 determines that run
switch 84 is closed, process 146 proceeds to a task 194. At task
194, motor control signal 126 (FIG. 6) is set to the pre-programmed
speed. In the MANUAL mode, actuation of up and down arrow buttons
102 and 104, respectively, adjust the pre-programmed manual motor
speed. At task 192, when microcontroller 118 determines that run
switch 84 is open, i.e., not actuated by the user, process 146
proceeds to a task 196. At task 196, motor control signal 126 (FIG.
6) is set to off in accordance with the particular sewing machine
utilized, as discussed above. Following either of tasks 194 and
196, process 146 proceeds to task 176 to generate motor control
signal 126 in accordance with the setting determined at either of
tasks 194 and 196.
[0067] Referring back to query task 190, when microcontroller 118
determines that MANUAL mode button 114 has not been selected,
process control proceeds to a query task 198. At query task 198,
microcontroller 118 determines whether OFF button 116 (FIG. 5) has
been selected. When OFF button 116 has been selected, process
control proceeds to a task 200. At task 200, motor control signal
126 (FIG. 6) is set to off in accordance with the particular sewing
machine utilized, as discussed above. Following task 200, process
146 proceeds to task 176 to generate motor control signal 126.
[0068] Referring back to query task 198, when microcontroller 118
determines that OFF button 116 has not been selected, process
control proceeds to a query task 202. At query task 202,
microcontroller 118 determines whether SETUP mode button 100 (FIG.
5) has been selected. When SETUP mode button 100 has been selected,
process control proceeds to a task 204. At task 204, motor control
signal 126 (FIG. 6) is set to off in accordance with the particular
sewing machine utilized, as discussed above. In addition, display
98 (FIG. 2) may be cleared. Following task 204, process 146
proceeds to a task 206.
[0069] In the SETUP mode, various menus are presented on display 98
(FIG. 2). These menus enable a user to select a machine type and a
duration for a power off time out. This machine type is utilized to
access lookup table 148 (FIG. 6) for potentiometer settings and/or
a correction factor related to the motor characteristics of the
particular sewing machine 34. The power off time out is a safety
feature that causes stitch regulator 50 to turn itself off after a
settable number of minutes of inactivity. In the SETUP mode, up and
down arrow buttons 102 and 104, respectively (FIG. 6), are utilized
to adjust the machine type selection and the power off time out. At
task 206, these setup control parameters are saved.
[0070] Following task 206, program control proceeds to task 176 to
generate motor control signal in the form of a motor off signal. Of
course, it should be understood that task 206 need not be complete
prior to generation of a motor off signal. Rather, generation of a
motor off signal may be performed in conjunction with task 204.
[0071] Referring back to query task 202, when microcontroller 118
determines that SETUP mode button 110 has not been selected,
process control proceeds to a query task 208. At query task 208,
microcontroller 118 determines whether NEEDLE JOG button 110 (FIG.
5) has been selected. When NEEDLE JOG button 110 has been selected,
process control proceeds to a task 210. At task 210, motor control
signal 126 (FIG. 6) is set to a minimum motor speed value in
accordance with the particular sewing machine utilized. This allows
the needle to be raised out of the fabric surface. In this mode,
motor 89 (FIG. 6) runs as long as NEEDLE JOG button 110 is held
down. In response to task 210, process 146 proceeds to task 176 to
generate motor control signal 126 at a minimum motor speed
setting.
[0072] Referring back to query task 208, when microcontroller 118
determines that NEEDLE JOG button 110 has not been selected,
process control proceeds to a query task 212. At query task 212,
microcontroller 118 determines whether BOBBIN button 108 (FIG. 5)
has been selected. When BOBBIN button 108 has been selected,
process control proceeds to a task 214. At task 214, motor control
signal 126 (FIG. 6) is set to a maximum motor speed value in
accordance with the particular sewing machine utilized. This allows
a bobbin to be wound. In this mode, motor 89 (FIG. 6) runs as long
as BOBBIN button 108 is held down. In response to task 214, process
146 proceeds to task 176 to generate motor control signal 126 at a
maximum motor speed setting.
[0073] Referring back to query task 212, when microcontroller 118
determines that BOBBIN button 108 has not been selected, process
control proceeds to a query task 218. At query task 218,
microcontroller 118 determines whether THREAD CUTTER button 106
(FIG. 5) has been selected. When THREAD CUTTER button 106 has been
selected, process control proceeds to a task 220. At task 220,
motor control signal 126 (FIG. 6) is set to off in accordance with
the particular sewing machine utilized, as discussed above. In
addition, a task 222 is executed. At task 222, microcontroller 118
signals thread cutter relay 134 (FIG. 6) to send thread cut signal
136 (FIG. 6). In this configuration, thread cut signal 136 is a
closure of thread cutter relay 134 causing a short across the
thread cutter inputs of sewing machine 34 (FIG. 1) at thread cut
connection 130 (FIG. 6). Following tasks 220 and 222, process 146
proceeds to task 176 to generate motor control signal 126 as a
motor off signal.
[0074] Referring back to query task 218, when microcontroller 118
determines that THREAD CUTTER button 106 has not been selected,
process control proceeds to a task 224. At task 224,
microcontroller 118 continues operation in the current mode in
accordance with the last buttons selected. In response to task 224,
process 146 proceeds to task 176 to generate motor control signal
126 in accordance with the current mode.
[0075] A task 226 is performed in connection with task 176. At task
226, the mode information is presented on display 98 (FIG. 5). Mode
information may include, for example, a machine type and power off
timeout in SETUP mode, notification of AUTO mode, desired stitch
density, and current motor velocity when in the AUTO mode, and
notification of MANUAL mode, pre-programmed motor speed, and on/off
notification when in the MANUAL mode. Of course, those skilled in
the art will recognize that the text presented in display 98 can
take on a great variation in accordance with the programmer's
preferences for data display.
[0076] Following task 226, process 146 loops back to system timer
query task 166 to monitor for a system timer overflow condition
causing another overall process loop to be initiated. Thus,
execution of stitch regulator operation process 146 enables a user
significant options for operating sewing machine 34 mounted on a
moveable platform, such as platform assembly 26 (FIG. 4).
[0077] In summary, the present invention teaches of a stitch
regulator for use with a sewing machine transported by a moveable
platform. The stitch regulator includes a microcontroller that uses
velocity signals of the moveable platform, and then uses motor
characteristics related to the type of sewing machine and a desired
stitch density to calculate an accurate motor speed. Thus, the
stitch regulator yields consistent stitch regulation across a
variety of sewing machine types and across a wide variety of motor
speeds for a sewing machine. The stitch regulator is located
separate from the sewing machine for ready incorporation with a
variety of sewing machines, moveable platforms, and quilting
tables. In addition, the keypad controls of the stitch regulator
are intuitive to utilize and the extruded housing, assembly, and
membrane keypad results in a stitch regulator that is durable and
cost effectively manufactured.
[0078] Although the preferred embodiments of the invention have
been illustrated and described in detail, it will be readily
apparent to those skilled in the art that various modifications may
be made therein without departing from the spirit of the invention
or from the scope of the appended claims. For example, the process
steps discussed herein can take on great number of variations and
can be performed in a differing order then that which was
presented.
* * * * *