Abstract:
A method for transferring an embroidery frame backward in case of thread breakage, includes the steps of: a) detecting the thread breakage to generate a thread breakage signal if the thread breakage occurs at a needle contained in needle holders; b) generating the control signal to control an embroidery-frame driver in response to the thread breakage signal; and c) transferring the embroidery frame backward in response to the control signal.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an embroidery machine. More particularly, the present invention relates to an embroidery machine and method for transferring an embroidery frame contained in the embroidery machine backward when a thread is broken at an embroidery operation. 
     DESCRIPTION OF THE PRIOR ART 
     Generally, an embroidery machine embroiders an embroidery design on a fabric fixed on an embroidery frame during a needle holder contained in a sewing device moves up and down, and simultaneously, the embroidery frame moves to X-axis and Y-axis directions. Because the embroidery machine embroiders the embroidery design on the fabric while the embroidery frame moves to the X-axis and Y-axis directions, an accurate movement and a low vibration of the embroidery frame are closely involved with the quality of embroidery. 
     Conventionally, the embroidery machine includes an alternating current (AC) servomotor or an induction motor for moving the needle holder up and down. Further, the embroidery machine includes a stepping motor for moving the embroidery frame to the X-axis and Y-axis directions. Twelve to twenty-five sewing machines are serially connected in the form of one shaft so as to improve the productivity of the embroidery machine. Because the embroidery machine embroiders the embroidery design on the fabric with threads of different colors, each sewing device has six to twelve needle holders and needles contained in each needle holder are threaded with the threads of the different colors. 
     Recently, a convenient input, copy, save, and edition of an embroidery design data is needed in the embroidery machine. Also a user prefers an automatic embroidery machine. The automatic embroidery machine has an automatic thread changing function according to the embroidery design. After the embroidery operation has been completed, the automatic embroidery machine has a function capable of cutting a thread. When the thread is broken at the embroidery operation, the automatic embroidery machine has a function capable of stopping the automatic embroidery machine and displaying an alarm indication. When the automatic embroidery machine is stopped due to an abnormal power-off, the automatic embroidery machine has a function capable of recovering a power supply. Furthermore, a manufacturer or a merchandiser wants to use the embroidery machine including a computer or a microprocessor for implementing the embroidery machine having multiple functions. 
     Referring to FIG. 1, there is shown a block diagram illustrating a conventional embroidery machine. As shown, the conventional embroidery machine includes a function selection panel  10 , an embroidery frame driver  20 , a thread breakage detector  30 , and a control unit  40 . The function selection panel  10  has function selection keys for selecting a plurality of functions. The embroidery-frame driver  20  drives the embroidery frame in response to a control signal outputted from the control unit  40 . The thread breakage detector  30  detects a broken thread. The control unit  40  controls the embroidery machine with a memory storing a program necessary to control the embroidery machine. If the thread breakage detector  30  detects the broken thread, the control unit  40  stops the embroidery operation. In addition, the control unit  40  is coupled to a setting data storage  50  and an embroidery design storage  60 . The setting data storage  50  and the embroidery design storage  60  can be located in the inside or outside of the control unit  40 . The setting data storage  50  stores a plurality of setting data needed for the embroidery operation, wherein the setting data includes an embroidery operation speed, selected needle holder-related information, etc. The embroidery design storage  60  stores embroidery design information. The control unit  40  can be implemented as a microprocessor. When the user selects a desired embroidery design from embroidery designs stored in the embroidery design storage  60 , the control unit  40  controls the embroidery-frame driver  20 . 
     When the thread is broken at the embroidery operation, the thread breakage detector  30  detects the broken thread and transmits a detection signal to the control unit  40 . The control unit  40  can include a display, a lamp or a buzzer not shown in FIG.  1 . When the thread is broken, the control unit  40  alarms the user through the display unit, the lamp or the buzzer. At this time, the control unit  40  controls the embroidery-frame driver  20  to stop the operation of the embroidery frame. Further, the user recognizes the broken thread through the display, the lamp or the buzzer. Then, the user finds out a needle of the broken thread and re-threads the needle of the broken thread. 
     At a state that the embroidery frame contained in the conventional embroidery machine is moved forward, the user should re-thread the needle of the broken thread. When the user re-threads the needle of the broken thread, the embroidery frame moved forward can be obstruction. Accordingly, the user employs a footstool to reach the needle of the broken thread. However, in case that the length of the embroidery machine is more than 750 mm, the user cannot easily re-thread the needle of the broken thread. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide an embroidery machine and method capable of transferring an embroidery frame backward so that a user can easily re-thread a needle of a broken thread in case of thread breakage. 
     It is, therefore, another object of the present invention to provide an embroidery machine and method capable of transferring an embroidery frame backward when a thread, especially, an upper-positioned thread is broken. 
     It is, therefore, further another object of the present invention to provide an embroidery machine and method capable of selectively setting an embroidery-frame transfer distance. 
     It is, therefore, still further another object of the present invention to provide an embroidery machine including an embroidery frame, which can be transferred backward or forward in response to a user request. 
     In accordance with a first aspect of the present invention, there is provided an embroidery machine for transferring an embroidery frame backward in case of thread breakage, the embroidery machine including the embroidery frame and needle holders holding needles, comprising: detection means for detecting the thread breakage to generate a thread breakage signal if the thread breakage occurs at a needle contained in the needle holders; transfer means for transferring the embroidery frame backward in response to a control signal; and control means, coupled to said detection means and said transfer means, for generating the control signal to control said transfer means in response to the thread breakage signal. 
     In accordance with a second aspect of the present invention, there is provided an embroidery machine for transferring an embroidery frame backward in case of thread breakage, the embroidery machine including the embroidery frame and needle holders holding needles, comprising: generation means for generating an embroidery-frame transfer request signal in response to a user request if the thread breakage occurs at a needle contained in the needle holders; transfer means for transferring the embroidery frame backward in response to a control signal; and control means, coupled to said transfer means and said generation means, for generating the control signal to control said transfer means in response to the embroidery-frame transfer request signal. 
     In accordance with a third aspect of the present invention, there is provided a method for transferring an embroidery frame backward in case of thread breakage, comprising the steps of: a) detecting the thread breakage to generate a thread breakage signal if the thread breakage occurs at a needle contained in needle holders; b) generating the control signal to control an embroidery-frame driver in response to the thread breakage signal; and c) transferring the embroidery frame backward in response to the control signal. 
     In accordance with a fourth aspect of the present invention, there is provided a method for transferring an embroidery frame backward in case of thread breakage, comprising the steps of: a) generating an embroidery-frame transfer request signal in response to a user request if the thread breakage occurs at a needle contained in needle holders; b) generating a control signal to control an embroidery-frame driver in response to the embroidery-frame transfer request signal; and c) transferring the embroidery frame backward in response to the control signal. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects and features of the instant invention will become apparent from the following description of preferred embodiments taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a block diagram illustrating a conventional embroidery machine; 
     FIG. 2 is an exemplary block diagram illustrating an embroidery machine for transferring an embroidery frame backward in case of thread breakage in accordance with the present invention; 
     FIG. 3 is an exemplary flow chart illustrating a method for transferring an embroidery frame backward in case of thread breakage in accordance with the present invention; and 
     FIG. 4 is another exemplary block diagram illustrating an embroidery machine for transferring an embroidery frame backward in response to a user request in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 2 is, there is shown an exemplary block diagram illustrating an embroidery machine for transferring an embroidery frame backward in case of thread breakage. The embroidery machine embroiders an embroidery design on a fabric fixed on an embroidery frame. The embroidery machine has the embroidery frame, the fabric fixed on the embroidery frame, needle holders having a plurality of needles. To perform an embroidery operation, the embroidery frame moves to X-axis and Y-axis directions and the needle holder moves up and down. A thread is threaded with a needle at the embroidery operation, wherein the thread includes an upper-positioned thread and an under-positioned thread. The embroidery machine includes a function selection panel  110 , an embroidery-frame driver  120 , a thread breakage detector  130 , an embroidery-frame transfer data storage  140 , and a control unit  150 . The function selection panel  110  includes a plurality of keys for selecting a function. The embroidery-frame driver  120  drives the embroidery frame, contained in the embroidery machine, in response to a control signal outputted from the control unit  150 . The thread breakage detector  130 , located at a plurality of needle holders, detects the thread breakage. The embroidery-frame transfer data storage  140  stores an embroidery-frame transfer distance data even if the power of the embroidery machine is off. The control unit  150  generates the control signal so as to control the embroidery-frame driver  120 . After the thread breakage detector  130  detects the thread breakage, the embroidery frame driver  120  transfers the embroidery frame backward in response to the control signal outputted from the control unit  150 . At this time, the embroidery-frame driver  120  transfers the embroidery frame backward by an embroidery-frame transfer distance of the embroidery-frame transfer distance data. 
     Furthermore, the control unit  150  can be implemented as a microprocessor. A setting data storage  160  and an embroidery design storage  170  are coupled to the control unit  150 , respectively. The setting data storage  160  and the embroidery design storage  170  can be located in the inside or outside of the control unit  150 . The setting data storage  160  stores a plurality of setting data including an embroidery operation speed, a selected needle holder-related information, etc., wherein the plurality of setting data can be inputted by the user at the embroidery machine. The embroidery design storage  170  stores embroidery design information so that the user at the embroidery machine can select a desired embroidery design from the embroidery design information. Furthermore, the embroidery-frame transfer data storage  140  can be implemented as a flash memory, a nonvolatile random access memory (RAM) or a floppy disk. The embroidery-frame transfer distance data can be read from the embroidery-frame transfer data storage  140 . Further, the embroidery-frame transfer distance data can be written to the embroidery-frame transfer data storage  140 . 
     Referring to FIG. 3, there is shown an exemplary flow chart describing a method for transferring the embroidery frame backward in case of the thread breakage. First, at step S 111 , the user at the embroidery machine selects a desired embroidery design stored in the embroidery design storage  170  through the function selection panel  110 . At this time, the user sets the embroidery operation speed and the selected needle holder-related information. Then, at step S 112 , the control unit  150  determines whether the user presses a start key contained in the function selection panel  110  to start the embroidery operation. If the start key is pressed, at step S 113 , the embroidery-frame driver  120  drives the embroidery frame in response to a start key signal from the control unit  150 . 
     Hereinafter, at step S 114 , the control unit  150  reads an embroidery operation data with respect to the desired embroidery design stored in the embroidery design storage  170 . Then, at step S 115 , the control unit  150  determines whether the embroidery operation data represents an embroidery operation completion data. If the embroidery operation data represents the embroidery operation completion data, at step S 116 , the control unit  150  carries out an embroidery operation stop routine. Otherwise, if the embroidery operation data does not represent the embroidery operation completion data, at step S 117 , the control unit  150  determines whether there is a thread breakage signal from the thread breakage detector  130 . Then, if there is not the thread breakage signal from the thread breakage detector  130 , at step S 118 , the embroidery machine resumes the embroidery operation. 
     Otherwise, if there is the thread breakage signal from the thread breakage detector  130 , at step S 119 , the control unit  150  carries out the embroidery operation stop routine. Then, at step S 120 , the control unit  150  determines whether the upper-positioned thread or the under-positioned thread is broken. If the upper-positioned thread is broken, at step S 122 , the lamp is turned off or the display displays an upper-positioned thread breakage indication. Then, at step S 123 , the control unit  150  reads the embroidery-frame transfer distance data from the embroidery-frame transfer data storage  140  so as to generate the control signal for controlling the embroidery-frame driver  120 . Then, at step S 124 , the embroidery-frame driver  120  transfers the embroidery frame backward by an embroidery-frame transfer distance of the embroidery-frame transfer distance data in response to the control signal. Then, the user re-threads the needle of the upper-positioned thread. Then, at step S 125 , the control unit  150  determines whether the user presses the start key to re-start the embroidery operation. If the user presses the start key, at step S 126 , the embroidery-frame driver  120  returns the embroidery frame to a previous embroidery-frame position. In other words, the embroidery-frame driver  120  transfers the embroidery frame forward by the embroidery-frame transfer distance of the embroidery-frame transfer distance data. 
     Otherwise, if the under-positioned thread is broken, at step S 121 , the lamp is turned on or the display displays an under-positioned thread breakage indication. At this time, the user re-threads the needle of the under-positioned thread. Then, the embroidery operation is repeated from the steps S 112 . 
     Referring to FIG. 4, there is shown another exemplary block diagram illustrating an embroidery machine for transferring the embroidery frame backward according to a user request. As shown, the embroidery machine includes a function selection unit  210 , an embroidery design storage  220 , a thread breakage detector  230 , an embroidery-frame transfer limit sensor  240 , a control unit  250 , a setting data storage  260  and an embroidery-frame driver  270 . Further, the embroidery machine further includes a display or a lamp. The display or the lamp indicates the thread breakage in response to a thread breakage signal outputted from the thread breakage detector  230 . Accordingly, when the display or the lamp indicates the thread breakage, the user sends the user request through a plurality of keys so that the embroidery-frame driver  270  can transfer the embroidery frame forward or backward. 
     As compared to the embroidery machine shown in FIG. 2, the embroidery machine shown in FIG. 4 further includes the embroidery-frame transfer limit sensor  240 . The embroidery-frame transfer limit sensor  240  senses a movement of the embroidery frame, e.g., the embroidery-frame transfer distance. The embroidery-frame transfer limit sensor  240  generates an embroidery-frame transfer stop signal if the embroidery frame reaches a predetermined limit position. The control unit  250  generates the control signal in response to the embroidery-frame transfer stop signal. The embroidery-frame driver  270  stops the embroidery-frame transfer in response to the control signal. The embroidery-frame transfer limit sensor  240  can be positioned on top, bottom, left and right side of the embroidery machine. 
     Further, the function selection panel  210  includes an embroidery-frame transfer data setting key, an embroidery-frame transfer key and an embroidery-frame return key. In order to transfer the embroidery frame backward when the thread is broken at the embroidery operation, the user can employ the embroidery-frame transfer data setting key, the embroidery-frame transfer key and the embroidery-frame return key. 
     The user can set the embroidery-frame transfer distance through the embroidery-frame transfer data setting key. Further, the setting data storage  260  stores an embroidery-frame transfer distance data, which is set through the embroidery-frame transfer data setting key. The user can transfer the embroidery frame backward by an embroidery-frame transfer distance of the embroidery-frame transfer distance data through the embroidery-frame transfer key. At this time, the function selection panel  210  generates the embroidery-frame transfer request signal. Then, the control unit  250  controls the embroidery-frame driver  270  in response to the embroidery-frame transfer request signal so that the embroidery-frame driver  270  can transfer the embroidery frame by the embroidery-frame transfer distance of the embroidery-frame transfer distance data. 
     The embroidery frame can be returned to a previous embroidery-frame position according to the user request through the embroidery-frame return key. At this time, the function selection panel  210  generates an embroidery-frame return request signal. Then, the control unit  250  controls the embroidery-frame driver  270  in response to the embroidery-frame return request signal so that the embroidery-frame driver  270  can return the embroidery frame to the previous embroidery-frame position. At this time, the embroidery-frame driver  270  transfers the embroidery frame forward by the embroidery-frame transfer distance of the embroidery-frame transfer distance data. As described above, the embroidery machine and method in accordance with the present invention can transfer the embroidery frame backward so that the user can easily re-thread the needle of the broken thread. 
     Although the preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.