Patent Application
20240183091
Longarm quilting is the process by which a longarm quilting machine is used to sew together a quilt top, quilt batting, and quilt backing into a finished quilt. The quilting stitch adds depth and a secondary design to the quilt top. The longarm quilting machine was developed because stitching together the three layers by hand is difficult and takes a long time. Sewing machines are not well adapted for quilting because sewing machines have a small throat which cannot effectively stitch a large, bulky quilt. Further, sewing machine heads are stationary requiring the user to move the quilt under the stitching assembly, which is difficult with large quilts.
A longarming system typically includes an industrial length quilting machine having a quilting head, a frame, a table, and several rollers on which the fabric layers and batting are attached. The quilt's layers are attached to different parts of the table or frame. The quilting machine is mounted to the frame to be movable in two dimensions relative to the stationary quilt/frame.
Precision timing is required between the needle and bobbin to ensure the components work together to make the stitch. A traditional quilting machine is shown in in
Several disadvantages result from mechanically linking the motor 50 to the needle and bobbin. One disadvantage is that the drive shafts 53, 55, belts 52, and linkages 54, 56 tend to vibrate and their movement can cause significant noise levels during operation. Further, the mass of the mechanical components requires significant acceleration/deceleration times. Still further, one of the most significant disadvantages of mechanically linking the components of a quilting machine relates to the needle and bobbin becoming unsynchronized. The relatively large number of mechanically linked components provides increased opportunity for the assembly to become unsynchronized. Once unsynchronized, manually adjusting the timing/synchronization of the components can be very difficult using conventional tools. Often a quilter will require the help of a professional or the manufacturer to re-synchronize the timing of the components.
There is therefore a need for an improved quilting machine that overcomes these another other disadvantages with the existing technology.
One aspect of the invention relates to a longarm quilting machine having a frame with an upper arm and a lower arm, each of the upper arm and the lower arm having a cavity therein and a distal portion. A needle bar drive mechanism configured to be combined with a needle is combined with a portion of the upper arm and a bobbin hook assembly configured to be combined with a bobbin is combined with a portion of the lower arm. A needle motor is operatively combined with the needle bar drive mechanism and configured to provide torque to the needle bar drive mechanism to cause the needle to move up and down. A bobbin motor is operatively combined with the bobbin hook assembly and configured to provide torque to the bobbin hook assembly to cause the bobbin to rotate beneath the needle. In one embodiment, the needle motor is positioned near the distal portion of the upper arm and the bobbin motor is positioned near the distal portion of the lower arm. The needle motor and the bobbin motor are smart motors and may be servo motors, stepper motors, or hybrid servo/stepper motors. In one embodiment the motors are hybrid servo-stepper motors configured to receive a command pulse stream instructing the movement of each motor. The motors may be open loop such that they do not communicate with each other or they may be closed loop such that they do communicate with each other. In one embodiment an electronic controller such as a circuit, processor, or servo controller, is in communication with the needle motor and the bobbin motor. The electronic controller uses position feedback information provided by the motors or by a position sensor in communication with the electronic controller to monitor and control the rotational position of each motor. In one embodiment, the position information is used to determine whether the needle and the bobbin are aligned relative to each other (synchronized). If the system determines the needle and bobbin are out of synchronization, then the electronic controller instructs the motors to stop. As explained below, the machine may then proceed to a synchronization mode to re-synchronize the needle and the bobbin.
Another aspect of the invention relates to a computer-implemented method of synchronizing the needle motor and the bobbin motor using a synchronization mode logic path. In some embodiments the controller is configured to use motor positional information to synchronize the needle motor and the bobbin motor upon the occurrence of one or more predetermined events. Such events may include turning the power ON, pausing quilting operation for a predetermined amount of time, or determining that the needle motor and the bobbin motor are not synchronized. The controller monitors the operation of the machine to determine the occurrence of one of the predetermined events. Upon the occurrence of a predetermined event, the controller determines the position of the needle motor to ensure the needle is raised out of the bobbin hook assembly so it will not be damaged by movement of the bobbin during the synchronization process. If the needle is safe, the controller sends a command to rotate the bobbin motor to a predetermined home position and then sends a command to rotate the needle motor to a corresponding predetermined home position. With each motor in its home position, the motors are synchronized and ready for operation. If the controller determines the needle is not raised out of the bobbin hook assembly at the beginning of the synchronization process, then the controller first sends a command to rotate the needle motor to a predetermined home position and then the bobbin motor to move the bobbin to the corresponding home position to ensure the needle and bobbin are synchronized.
Another aspect of the invention relates to a method of using the quilting machine described above. The method includes turning the machine ON to power the controller and the motors. Instructing the controller to align the needle and the bobbin relative to each other by determining the position of the needle motor to ensure the needle is raised out of the bobbin hook assembly. If the needle is safe, sending the controller a command to rotate the bobbin motor to a predetermined home position and then sending a command to rotate the needle motor to the corresponding home position to synchronize the needle and bobbin. If the controller determines the needle is not raised out of the bobbin hook assembly at the beginning of the synchronization process, then first sending the controller a command to rotate the needle motor to a predetermined home position and then sending a command to the bobbin motor to move the bobbin to a corresponding predetermined home position to ensure the needle and bobbin are synchronized.
The invention generally relates to a longarm quilting machine 10.
Each arm 18, 21 has a length extending from its connection with the intermediate portion 15 to its respective end 18C, 21C. Each arm 18, 21 also has a midpoint which is about halfway between the intermediate portion 15 and the respective end 18C, 21C (about half of the length). In one embodiment, the distal portion 18B, 21B of each arm 18, 21 is defined as the portion extending from the midpoint of each arm 18, 21 toward its end 18C, 21C. In another embodiment the distal portion 18B, 21B of each arm 18, 21 is defined as the portion beginning at each respective end 18C, 21C and extending about one-third of the length toward the intermediate portion 15.
In one embodiment, the needle motor 20A is positioned at the distal portion 18B of the upper arm 18 and the bobbin motor 20B is positioned at the distal portion 21B of the lower arm 21. In the embodiment shown, the motors 20A, 20B are positioned inside the respective cavities of the upper arm 18 and lower arm 21. Positioning the motors 20A, 20B near the ends 18C, 21C of the arms 18, 21 leaves the proximal portions 18A, 21A of the arms 18, 21 as well as the intermediate portion 15 of the frame 11 free from motors, belts, linkages, gears, and other mechanical drive components. Without internal mechanical drive components, the frame 11 and proximal portions 18A, 21A of the arms 18, 21 may be contoured to a wide variety of aesthetically pleasing shapes or configurations.
A controller 22, such as a circuit, processor, or servo controller, with control electronics is in communication with the needle motor 20A and the bobbin motor 20B.
In one embodiment the position of each motor 20A, 20B is determined every time the motor 20A, 20B (or any components being moved by the motor 20A, 20B, such as the drive shafts 32) passes a single predetermined rotational position, such as the UP position or the DOWN position. In this manner, the rotational position for each motor 20A, 20B is determined and compared once per stitch. In another embodiment rotational position information of each motor 20A, 20B (or related components) is determined at multiple predetermined positions, such as the UP position and the DOWN position, thereby allowing the system to determine synchronization of the motors 20A, 20B every half stitch. In yet another embodiment, the controller 22 is specially programmed to know the rotational position information of each motor 20A, 20B at all times such that a particular position of the needle motor 20A should always correspond to a particular position of the bobbin motor 20B. Regardless of the means and frequency of determining synchronization, if the controller 22 determines the motors 20A, 20B or their related components are not synchronized, the motors 20A, 20B are instructed to stop and/or the machine 10 turns OFF.
In one embodiment the sensors 33 are optical sensors configured to read the position of the motors 20A, 20B or one or more components being rotated by the motors 20A, 20B, such as the drive shafts 32. The rotating components (e.g., drive shafts 32) may include a collar having a band with one or more markers such as colored stripes or other visible indicators. The optical sensors 33 determine the position of the markers for each motor 20A, 20B at intervals (such as the UP and/or DOWN position as described previously) and sends a position signal to the controller 22 to determine whether the components are synchronized. In another embodiment the sensors 33 are magnetic sensors configured to read a magnetic collar combined with the rotating components (e.g., drive shafts 32).
It should be noted that in some embodiments the motors 20A, 20B do not rotate at the same speed. Instead, in some embodiments the bobbin motor 20B rotates twice as fast as the needle motor 20A. In these embodiments the controller 22 is programmed to correlate a single position of the bobbin motor 20B with multiple corresponding positions of the needle motor 20A to achieve synchronization. Further, it should be understood the positions of the motors 20A, 20B and related components discussed herein with respect to synchronization correspond to positions of the needle 24 and bobbin 17 as those components move relative to each other. The controller 22 uses position feedback to control the motion, speed, and position of each motor 20A, 20B.
When the machine 10 is turned OFF, the controller 22 sends a frequency pulse to rotate the motors 20A, 20B to a predetermined position before turning the motors OFF. In the embodiment described above with respect to
Having thus described the invention in connection with the preferred embodiments thereof, it will be evident to those skilled in the art that various revisions can be made to the preferred embodiments described herein without departing from the spirit and scope of the invention. It is my intention, however, that all such revisions and modifications that are evident to those skilled in the art will be included with in the scope of the following claims.
