JP2613374B2 - Needle thread cutting device in embroidery sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims to solve the following problems.

INDUSTRIAL APPLICABILITY The present invention relates to an embroidery sewing machine, in which an upper thread is cut in order to change an embroidery sewing place or a color of an upper thread for embroidery sewing. It concerns the device.

(Prior Art) In a conventional thread cutting device, an upper thread near a lower thread is cut by a cutting blade that moves along a lower surface of a needle plate and near a needle hole through which the lower thread passes. Are known (for example, see Japanese Utility Model Application Laid-Open No. 58-26472 and Japanese Utility Model Application Laid-Open No. 58-84086).

(Problems to be Solved by the Invention) However, first of all, if the operation of the cutting blade is not set with extremely high accuracy, the lower thread parallel to the vicinity of the upper thread every time the upper thread is cut may be mistaken. Since the cut end of the lower thread is left on the back surface of the cloth, the back surface of the embroidered cloth is very dirty. Second, the needle thread is cut at a position close to the needle, so that the needle thread remaining on the needle side becomes extremely short, and as a result, the needle thread often moves from the needle as the needle is raised. There was also a problem of getting out.

According to the present invention, only the upper thread close to the cloth can be cut accurately without cutting the lower thread or the upper thread connected to the needle and having a shorter distance to the needle. In this manner, the upper thread in the embroidery sewing machine is configured such that only the target thread is accurately cut even if the operating accuracy of the cutting blade is rougher than before, while leaving the needle-side upper thread in a long state. It is intended to provide a cutting device.

(Means for Solving the Problems) In the present invention, a shuttle is provided below a needle plate having a needle passage hole, and above the needle plate, the needle can be lowered toward the shuttle through the needle passage hole. An embroidery sewing machine comprising a needle that can move up and down as described above, and by moving the needle up and down, embroidery sewing is performed on the cloth by the upper thread that is fed through the needle and the lower thread that is fed from the shuttle.
On the lower side of the needle plate, in order to dispel the lower thread between the needle passage hole and the shuttle from side to side,
The lower thread wiper, which is movable between the retreating position and the retreat position, is positioned in the upper thread loop in the process of being pulled up in a loop state after the upper thread has passed through the shuttle. An upper thread hooking piece movable between a hooking position for hooking the loop and a retracted position, and the upper thread hooking piece is located on the cloth side in a state where the upper thread hooking piece is located in the loop of the upper thread. The upper thread and the needle-side upper thread are formed to be wide so as to be separated from each other, and the lower thread removing section of the lower thread removing piece is cut by the cutting blade at the time of cutting the upper thread on the cloth side. The lower thread is set at a lateral position separated by the cloth-side upper thread in the upper thread in the loop state so that the lower thread is not cut by the blade. Repels the lower thread, and the upper thread hook In the present state, avoid the position of the lower thread displaced by the lower thread wiper and the position of the needle-side upper thread in the upper thread in the loop state, and the cloth side of the upper thread in the loop state. A cutting blade for cutting only the upper thread at the upper thread position is provided.

(Operation) When the bobbin wiper moves to the sweeping-out position, the bobbin thread between the needle passing hole and the shuttle is swept away by the bobbin wiper away from the locus of the cloth-side upper thread. When the needle thread hooking piece is moved to the hooking position, when the needle thread that has been lowered by the needle and passed through the hook comes off the hook, it is hooked in a loop on the needle thread hooking piece, and the cloth side needle thread and needle side Divided into yarn. Thereafter, only the upper thread on the cloth side separated from the other threads is cut.

(Embodiment) Drawings showing an embodiment of the present application will be described below. 1 is a needle plate having a needle passage hole 1a, 2 is a shuttle located below the needle plate 1, an outer shuttle 3 rotated by a shaft 50, and housed and fixed in the outer shuttle 3. It is configured in a well-known manner with an inner hook 5 that is prevented from rotating by a typical hook stopper 4. A bobbin case 6 for a bobbin 6a for a lower thread is accommodated in the inner hook 5. 6b shows a yarn guide.
Reference numeral 7 denotes a needle disposed above the needle plate 1, which is vertically movable so as to be able to descend through the needle passage hole 1a as is well known.

Next, 8 is a rotary solenoid fixed to the frame F, 9 is a first swing arm (hereinafter referred to as a first arm 9) fixed to a rotating shaft 8a of the rotary solenoid 8, and a horizontal arm. It is composed of 10 and a standing arm 11. Numeral 12 denotes a lower thread wiper fixed to the mounting portion 11a of the upright arm 11 with mounting screws 13 and 13 so as to be adjustable in position. It is movably disposed between the retracted position shown in the drawing and the dispensing position shown in FIG. 4, and in the dispensing position, the lower thread a is repelled to a position outside the movement locus of the cutting blade described later. .

Next, reference numeral 14 denotes an upper thread hooking piece provided at the distal end of the first arm 9, as shown in FIG. 1 and in a retracted position away from the shuttle 2, as shown in FIGS. The hook 2 is movably disposed between a hooking position facing the hook 2 and the loop-shaped upper thread b passing through the hook 2 in the hooking position in the process of being pulled upward. . The upper thread hooking piece 14 is a pair of forked hooks 14a, 14a.
The upper thread b1 (meaning the upper thread b1 connected to the cloth 15) and the upper needle thread b2 (connected to the needle 7) of the loop-shaped upper thread b which is formed to be wide and hooked on itself. (Meaning the upper thread b2) on the side of the contact. The upper thread hooking piece 14 may be provided on a member that is moved by a drive source different from the rotary solenoid 8. Next, 16 is a rotary solenoid fixed to the frame F, 17 is a rotating arm fixed to a rotary shaft 16a of the rotary solenoid 16, and a pin 18 is protruded from the top surface of the tip. . Reference numeral 19 denotes a second swing arm (hereinafter, referred to as a second arm 19) pivotally attached to the frame F via a support shaft 20.
The horizontal arm 21 is fixed to the support shaft 20, and the standing arm 22 is fixed to the horizontal arm 21. An engagement groove 21a is formed in the horizontal arm 21, and the pin 18 is engaged in the engagement groove 21a. An attachment portion 22a is formed on the upright arm 22. Reference numeral 23 denotes a thread guide groove formed in the mounting portion 22a, reference numeral 24 denotes a cutting blade fixed to the mounting portion 22a by a mounting tool 25 formed of a leaf spring, and the cutting edge thereof is a thread guide groove 23.
Is located across the bottom of the As shown in FIG. 1, the cutting blade 24 is moved away from the shuttle 2 and
It is disposed movably between the operating position indicated by the imaginary line in the figure, passes through the expected position of the cloth side upper thread b1 hooked on the upper thread hooking piece 14 during the movement, and remains at that position. The cloth side upper thread b1 to be cut is cut.

In the above configuration, when the upper thread a is passed through the hole of the needle 7 and the bobbin 6a of the lower thread b is set in the bobbin case 6 and the embroidery sewing machine is operated, the needle 7 moves up and down through the needle through hole 1a. The embroidery stitch 15 can be applied to the cloth by rotating the outer hook 3 as well as in a known manner. Next, when it is desired to cut the upper thread b at the time of shifting to the embroidery sewing of another pattern after finishing the embroidery sewing of one pattern, mechanically or by operating a switch for cutting the upper thread, FIG. It operates as shown in FIG. 9 to cut the cloth side upper thread b1 of the upper thread b.

First, at the time point (a) at a cycle angle of 0 degree shown in FIG. 9, the balance is in the horizontal position, the needle point of the needle 7 is located at the top dead center, and the lower thread wiper 12 and the upper thread hook The piece 14 is located at the retracted position shown in FIG. Next, at the point (b) of the cycle angle of 25 degrees, the needle 7 starts descending, and the blade point 3a of the outer hook 3 is positioned directly above. At the same time, the rotary solenoid 8 is energized, whereby the first arm 9 is swung to move the lower thread removing piece 12 to the removing position shown in FIG. 4 and FIG. 4
It is moved to the hooking position shown in FIG. As a result, the lower thread wiper 12 hooks the lower thread a between the shuttle 2 and the needle passing hole 1a as shown in FIGS. 7 and 8 (1), and moves the lower thread a to the cutting blade 24. Dismiss off track. In addition, the upper thread hooking piece
14 enters the shuttle 2 as shown in FIG.

Next, when the cycle angle reaches 120 degrees (C), the needle point of the needle 7 enters the needle passage hole 1a, and the blade point 3a of the outer hook 3 is positioned directly below. Next, at the point (d) of the cycle angle of 180 degrees, the tip of the needle 7 is positioned at the bottom dead center, and thereafter, at the point of the cycle angle of 205 degrees (e), the tip of the needle starts slightly rising. At the same time, the point 3a of the outer hook 3 is again positioned directly above as shown in FIG. 8 (2). At this point, the upper point b of the outer hook 3 is hooked by the needle thread b drawn out by the needle 7. Next, when the cycle angle reaches 290 degrees (f),
The needle point of the needle 7 is raised near the rising end, and the sword tip 3a of the outer hook 3 is again pivoted directly downward, so that the sword tip 3a hooks the upper thread b as shown in FIG. 8 (3). To transport. In this process, the cloth side upper thread b1 of the upper thread b contacts one hook 14a,
The upper thread b passes through the inner hook 5. Then, cycle angle 35
At the third time point (g), the needle thread b finishes passing through the inner hook 5, and the blade point 3a is turned to the side and turned upward. At this point, the needle thread b comes off the blade point 3a and is pulled upward. (By balance). As a result, the needle side upper thread b2 of the upper thread b
Is hooked on the other hook 14a of the upper thread hooking piece 14, and the upper thread b
As shown in FIGS. 7 and 8 (4), a triangular shape is formed between the needle passage hole 1a and the upper thread hooking piece 14.

Next, when the cycle angle reaches 360 degrees (h), the rotary solenoid 16 is energized, and the second arm 19 is thereby turned on.
Is pivoted to move the cutting blade 24 from the retracted position in FIG. 1 to an operating position indicated by a virtual line in FIG. As a result, the second
The thread guide groove 23 of the arm 19 and the cutting edge of the cutting blade 24 are shown in FIGS.
As shown in FIG. 5 (5), the cloth side upper thread b1 between the needle threading hole 1a and the upper thread hooking piece 14 is traversed, and the cloth side upper thread b1 is cut by the cutting blade 24. The energization of the rotary solenoid 16 is stopped at a point (e) after a short time has passed, and the cutting blade 24 is returned to the retracted position. In addition, the above-mentioned rotary solenoid 8
The energization of the lower thread removing piece 12 and the upper thread hooking piece 14 is returned to the retreat position at the time (N) after the cloth side upper thread b1 is cut. Thereafter, the cloth is traversed and embroidery sewing is started at a new position in the cloth. In this case, since the lower thread a has not been cut, the end of the lower thread a may come out (hang down) on the back surface of the cloth 15. Without it, the back side of the embroidery cloth can be beautifully finished. In addition, since the needle-side upper thread b2 is not cut and a sufficient length of thread is continued below the needle 7,
Embroidery sewing can be started without an accident by preventing the needle thread b from coming off from the needle 7 at the start of sewing.

In the above-described embodiment, the movement of the lower thread removing piece 12 to the removing position and the movement of the upper thread catching piece 14 to the catching position are performed from the time (b) to the time (c) at T1 ( This may be performed at any time during the time when the needle 7 is above the needle plate 1). Further, the cutting of the cloth side upper thread b1 by the cutting blade 24 is performed by lowering the balance from the point in time when the triangle of the upper thread b is completed between the threading hole 1a and the upper thread hooking piece 14 (g). Until the time to start
This may be performed at any time during T2 (while the upper thread b is in a tensioned state). Furthermore, the lower thread wiper 12 and the upper thread hooking piece 14
The return to the respective retracted positions may be performed at any time of T3 from the time when the cutting of the cloth-side upper thread b1 is completed to the time when the needle 7 starts to enter below the needle plate 1 next.

(Effects of the Invention) As described above, according to the present invention, after the embroidery sewing of one pattern is completed, when the upper thread b is to be cut in the case of shifting to the embroidery sewing of another pattern, the sewing speed is temporarily reduced. ,
Even if slack occurs in the lower thread due to the tension of the lower thread or the nature of the lower thread itself, and the slack causes the lower thread to enter the movement locus of the cutting blade, the lower thread wiper 12 Thus, the lower thread a is positively dislodged from the locus of the upper thread b1 on the cloth side, and the upper thread hooking piece 14
Thus, by the double operation of separating the upper thread b1 on the cloth side and the upper thread b2 on the needle side from each other, the position of the lower thread a from the upper thread b1 at the upper thread position on the cloth side in the upper thread in the loop state. Also, keep the needle-side upper thread b2 away, and in this state, the cloth-side upper thread b1
The operation of the cutting blade 24 is increased,
It can be operated roughly and can cut only the upper thread b1 on the cloth side accurately without cutting the lower thread a or the upper thread b2 on the needle side even when it is operated greatly, and cuts the upper thread b1 on the cloth side. This has the advantage that the yarn remaining on the lower side can be made sufficiently long, and is effective in solving the conventional problems.

[Brief description of the drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a plan view of a shuttle portion of an embroidery sewing machine, FIG. 2 is a right side view of FIG. 1, FIG. 3 is a sectional view taken along the line III-III of FIG. Is an operation explanatory view of FIG. 1, FIG. 5 is a right side view of FIG. 4 showing a partial cross section, FIG. 6 is a cross sectional view taken along the line VI-VI, and FIG. FIG. 8 is a front view of the shuttle portion, FIG. 8 is a perspective view for explaining the operation in the order of (1) to (5), and FIG. 9 is a time chart for explaining the operation. 1 ... needle plate, 1a ... needle through hole, a ... bobbin thread, b ...
Upper thread, b1 ... cloth side upper thread, b2 ... needle side upper thread, 12 ... lower thread wiper piece, 14 ... upper thread hooking piece, 24 ... cutting blade.

Claims (1)

(57) [Claims] A needle is provided below a needle plate having a needle passage hole, and a vertically movable needle which can be lowered toward the shuttle through the needle passage hole is provided above the needle plate. In addition, by moving the needle up and down, in an embroidery sewing machine that performs embroidery sewing on a cloth with an upper thread fed through a needle and a lower thread fed from a shuttle, on the lower side of the needle plate, A lower thread wiper movably between a withdrawal position and a retracted position in order to laterally remove the lower thread between the needle passage hole and the shuttle from there, The upper thread is positioned within the loop of the upper thread in the process of being pulled up in a loop state after passing through the hook, and is movable between a hooking position for hooking the loop and a retracting position. A thread catching piece, and The hooking piece is formed to be wide so that the upper thread on the cloth side and the upper thread on the needle side are separated from each other when positioned in the loop of the upper thread. The retreat position is set at a side position away from the cloth side upper thread in the upper thread in the above loop state so that the lower thread is not cut by the cutting blade at the cloth side upper thread cutting side by the cutting blade. Further, below the needle plate, the lower thread wiper repels the lower thread, and in the state where the upper thread hooking piece is present in the loop of the upper thread, the lower thread wiper repels the lower thread. The position of the lower thread and the position of the needle side upper thread in the upper thread in the loop state are avoided, and only the upper thread at the cloth side upper thread position in the upper thread in the loop state is cut. An upper thread cutting device in an embroidery sewing machine, comprising a cutting blade.