Stitch regulator for a sewing machine
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).
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 INVENTIONThe 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 INVENTIONQuilting 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.
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 INVENTIONAccordingly, 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 DRAWINGSA 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:
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 (
Referring to
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 (
First carriage 54 includes first wheels 58 configured to engage with rails on frame 22 (
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 (
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
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 (
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 (
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 (
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.
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 (
The three terminals (TIP, RING, TERM3) form the electrical interface of first conductor 86 for foot pedal connection 88 (
Run relay 124, when energized, connects foot pedal connection 88 (
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 (
Profiling is accomplished, for example, by measuring the motor speed (e.g. revolutions per minute) of motor 89 (
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.
Stitch regulator operation process 146 begins with a task 162. At task 162, stitch regulator 50 (
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 (
For example, following task 168, a query task 170 is performed. At query task 170, microcontroller 118 determines whether AUTO mode button 112 (
Following task 172, a task 174 is performed. At task 174, microcontroller calculates motor control signal 126 (
Referring to
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 (
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 (
Referring back to process 146 (
When in the AUTO mode, up and down arrow buttons 102 and 104, respectively (
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 (
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 (
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 (
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 (
In the SETUP mode, various menus are presented on display 98 (
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 (
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 (
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 (
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 (
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 (
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 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.
Type: Application
Filed: Nov 30, 2005
Publication Date: Jun 1, 2006
Inventors: Thomas Pfeifer (Glendale, AZ), Mark Carlin (Gilbert, AZ), Christopher Boyd (Goodyear, AZ)
Application Number: 11/291,651
International Classification: D05B 11/00 (20060101);