US20060112866A1

US20060112866A1 - Stitch regulator for a sewing machine

Info

Publication number: US20060112866A1
Application number: US11/291,651
Authority: US
Inventors: Thomas Pfeifer; Mark Carlin; Christopher Boyd
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-12-01
Filing date: 2005-11-30
Publication date: 2006-06-01

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).

Description

RELATED INVENTION

The present invention claims priority under 35 U.S.C. §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

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

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.
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.
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.
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.
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.
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.
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.
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.
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.
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

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.
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.
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.
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.
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

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:
FIG. 1 shows a front perspective view of a prior art quilting table;
FIG. 2 shows a front perspective view of a stitch regulator in accordance with a preferred embodiment of the present invention;
FIG. 3 shows an exploded side view of a housing of the stitch regulator;
FIG. 4 shows an exploded perspective view of a platform assembly with a stitch regulator mountable thereon;
FIG. 5 shows a partial front view of the stitch regulator illustrating keypad controls;
FIG. 6 shows a block diagram of the stitch regulator;
FIG. 7 shows a block diagram of a portion of the stitch regulator;
FIG. 8 shows a graph typifying a motor characteristic for a sewing machine;
FIG. 9 shows a flow chart of a stitch regulator operation process; and
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

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).
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.
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.
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.
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.
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.
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.
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).
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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).
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.
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.
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.
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.
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.
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).
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).
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.
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).
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.
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).
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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).
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.
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.

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 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.