JP2009153725A - Needle threading device for sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a needle threading device for a sewing machine, which allows string to hardly come off after performing a needle threading work without requiring, especially skill for a work of an operator. <P>SOLUTION: The needle threading device is provided with a needle threading shaft in close proximity to a needle bar supporting and moving a needle up and down, a needle threading hook of which the hook part can be introduced/removed into/from a needle hole, a regulation mechanism for regulating the descent limit of the needle threading shaft, and a rotation mechanism for rotating the needle threading shaft in proximity to the limit of the shaft by a specified angle so as to insert the hook part through the needle hole. The needle threading device has an needle thread lock part for keeping needle thread hooked by the hook part at a position higher than the hook part till prescribed tension is applied after pressing down the needle threading shaft by an operational body in proximity to the lower limit and rotating the operational body and inserting the hook part to the needle hole of the sewing needle, and then, cutting the useless needle thread. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a threading device for a sewing machine that prevents a thread from coming out of a needle hole again after a threading operation is performed.

  Conventionally, a sewing machine equipped with a threading device that can be easily threaded through a needle hole of a sewing needle has been put to practical use in sewing work for forming stitches on a work cloth that is a sewing object using a sewing machine. (See Patent Document 1). For example, in Patent Document 1, when the operator lowers the threading lever, the threading shaft and the slider guide shaft descend, and the sliding pin on the upper end of the threading shaft contacts the locking portion on the needle bar side. At the stage of contact, the height positions of the threading shaft and the slider guide shaft are regulated. Thereafter, when the threading lever is further lowered, the threading shaft provided with the sliding pin is rotated by a predetermined angle by the cam mechanism including the sliding pin, and the hook attached to the lower end of the threading shaft is needled. After threading through the hole, threading is performed.

  FIG. 1 is a partial perspective view schematically showing a conventional threading operation of a sewing machine. First, the push-down lever is lowered, the cloth presser is pushed down to the lowest point, and the handwheel is turned to keep the sewing needle 15 near the highest point. In this state, as shown in FIG. 1 (a), the upper thread A is wound through the thread hooking portion 20. Next, as shown in FIG. 1B, the operating lever 18 is pushed down to the lowest point while the upper thread is held.

  Then, as shown in FIG. 1C, the operating lever 18 is rotated in the direction in which the hook-shaped flange portion 17 between the guide portions 21 is inserted into the needle hole 16, and the flange portion 17 is rotated. In this state, as shown in FIG. 1 (d), the upper thread A is wound around the hook portion 17 so that the upper thread A is hooked, and as shown in FIG. Hold in front.

As shown in FIG. 1 (f), by pushing the operating lever 18 from the rear, the threading hook rotates, the hook 17 passes through the needle hole 16, and the upper thread A loops behind the needle hole 16. Pass through. Then, as shown in FIG. 1 (g), the threading is completed by pulling the upper thread A in a loop to the other side.
Japanese Utility Model Publication No. 06-055585

  However, in the threading device shown in Patent Document 1, although the threading operation can be reliably performed up to FIG. 1 (f), the operator gently holds the upper thread A as shown in FIG. 1 (e). Then, since it is held in front of the front, there is a risk that the upper thread A will be pulled too strongly when it passes and the upper thread A that has passed through it will be pulled out again. Therefore, in order to perform the threading operation reliably, there is a problem that the operator is required to have skill in the operation.

  The present invention has been made in view of such circumstances, and provides a threading device for a sewing machine that does not require the operator to be particularly skilled in the work and has a low risk of the thread coming out again after the threading operation. For the purpose.

  In order to achieve the above object, the threading device for a sewing machine according to the first aspect of the present invention is capable of moving up and down close to a needle bar for moving a supported sewing needle up and down, and centering on an axis. A threading shaft that is supported so as to rotate; a collar portion that can be inserted into a needle hole of a sewing needle; and a guide portion that guides the collar portion to the needle hole. A threading hook that is rotatably mounted on the lower end of the threading shaft as a unit with an operating body that can be moved vertically and rotated about the threading shaft, and a lowering limit of the threading shaft A threading device for a sewing machine comprising: a regulating mechanism for regulating the position; and a turning mechanism for turning the guide part by a predetermined angle so that the hook part is inserted into a needle hole of a sewing needle in the vicinity of a lowering limit point of the threading shaft. The threading shaft is moved near the lowering limit point by the operating body. The upper thread hooked on the collar is applied with a predetermined tension at a position higher than the collar while the collar is pushed down and rotated by rotating the operating body. And an upper thread locking portion capable of cutting an unnecessary upper thread.

  In the first invention, the thread is supported so that it can be moved up and down at a position close to the needle bar for moving the supported sewing needle up and down and can rotate around the shaft. One through shaft is provided. The lower end portion of the threading shaft has a hook portion that can be inserted into the needle hole of the sewing needle, and a guide portion that guides the hook portion to the needle hole. A threading hook integrated with an operating body that can be rotated about the threading shaft is attached to the lower end of the threading shaft. The rotation mechanism rotates the threading hook by a predetermined angle so that the collar portion is inserted into the needle hole of the sewing needle near the lowering limit point of the threading shaft. The operator pushes the threading shaft down to the vicinity of the lowering limit point through an operating body such as a lever and rotates the operating body, thereby inserting the heel portion into the needle hole of the sewing needle. An upper thread locking part is provided at a position higher than the hook part, and the upper thread hooked on the hook part is pulled to the upper thread locking part in a state where a predetermined tension is applied, and locked to the upper thread locking part. Cut the unnecessary upper thread in the

  As a result, it is not necessary to continuously apply the necessary tension with the finger to the upper thread that is hooked on the collar, and the thread can be reliably threaded as the collar is pulled out of the needle hole. Never pull out the thread by mistake. Therefore, it is possible to reliably perform the threading operation without requiring the operator to be particularly skilled in the operation.

  Further, in the threading device for a sewing machine according to the second invention, in the first invention, the upper thread locking portion is provided on a side opposite to a direction of inserting the sewing product with respect to a position of the needle hole of the sewing needle. It is characterized by being.

  In the second invention, the upper thread locking portion is provided on the opposite side to the direction in which the workpiece is inserted with respect to the position of the needle hole of the sewing needle, so that the tension in the opposite side rather than the front side is applied to the upper thread. There is no risk of pulling out the upper thread by mistake after threading the upper thread.

  In the threading device for a sewing machine according to a third aspect of the present invention, in the first or second aspect of the invention, the upper thread locking portion is provided on a pressing lever that presses down a cloth presser that presses a sewing product. And

  In the third aspect of the invention, the upper thread locking portion is provided in the push-down lever that pushes down the cloth presser that presses the workpiece. By providing the upper thread locking part on the push-down lever, there is no need to make a layout design to provide a separate upper thread locking part, and it is surely located at a higher position than the collar and on the opposite side, not the front side. Since the tension in the direction can be applied to the upper thread, the threading operation can be reliably performed without requiring the operator to be particularly skilled in the operation.

  According to a fourth aspect of the threading device for a sewing machine of the present invention, in the third aspect, the upper thread locking portion includes a guide groove for guiding the upper thread, and the upper thread is locked to the bottom of the guide groove. It has a locking member and a cutting member for cutting the upper thread.

  In the fourth invention, the upper thread locking portion includes a guide groove for guiding the upper thread, and has a locking member for locking the upper thread and a cutting member for cutting the upper thread at the bottom of the guide groove. . The upper member hooked on the collar portion can be held by the locking member until a predetermined tension is applied, and the unnecessary upper yarn can be cut by the cutting member.

  According to the first invention, it is not necessary to continuously apply the necessary tension with the finger to the upper thread hooked on the collar, and the thread can be reliably threaded as the collar comes out of the needle hole. The upper thread that has been threaded is not pulled out accidentally. Therefore, it is possible to reliably perform the threading operation without requiring the operator to be particularly skilled in the operation.

  According to the second aspect of the invention, the upper thread locking portion is provided on the side opposite to the direction in which the workpiece is inserted with respect to the position of the needle hole of the sewing needle, thereby increasing the tension in the opposite direction rather than the front direction. It can be applied to the thread, and there is no risk of pulling out the upper thread by mistake after threading the upper thread.

  According to the third invention, by providing the upper thread locking portion on the push-down lever, there is no need to perform an arrangement design for separately providing the upper thread locking portion, and the position is surely higher than the collar portion. Since the tension in the opposite direction, not the front direction, can be applied to the upper thread, the threading operation can be reliably performed without requiring the operator to be particularly skilled in the operation.

  According to the fourth invention, the upper thread hooked on the collar portion can be held by the locking member until a predetermined tension is applied, and the unnecessary upper thread can be cut by the cutting member.

  Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments thereof. In the following description, the front, rear, left and right viewed from the operator operating the sewing machine will be described as front, back, left and right. FIG. 2 is a cross-sectional view in the lateral direction including the needle bar showing the configuration of the arm portion of the sewing machine according to the embodiment of the present invention, and FIG. 3 is the thread of the sewing machine according to the embodiment of the present invention. It is sectional drawing in the surface of the left-right direction containing the needle bar which shows the mounting state of a threading device. As shown in FIG. 2, the arm portion of the sewing machine according to the present embodiment is disposed close to the needle bar 2 and the sewing needle 15 on the shaft support portion 1 (see FIG. 3) that is swung left and right with the upper end as a fulcrum. The threading shaft 3 is attached.

  As shown in FIG. 3, the needle bar 2 is connected to a main shaft (not shown) by a needle bar holder 4 via a crank and a rod, and is moved up and down by the rotation of the main shaft. A positioning block 5 as a positioning member is fixed immediately above the needle bar holder 4. 4 is a cross-sectional view of the sewing machine according to the embodiment of the present invention, taken along the line IV-IV in FIG. As shown in FIG. 4, the positioning block 5 has a receiving shelf 6 protruding to the side at the lower part on the side facing the threading shaft 3, and slightly bent toward the side at the upper center above the receiving shelf 6. It has a protruding portion 8 that protrudes into a shape and forms a groove 7 between which a pin, which will be described later, can be fitted. Further, the guide block 11 is provided with a protruding portion 23 that can come into contact with the receiving shelf 6 when the threading shaft 3 is lowered.

  Returning to FIG. 3, the threading shaft 3 is urged so as to be always pulled up by the spring 10, and is rotated by being fitted into a vertical groove (not shown) formed in the shaft support portion 1 at the upper portion. A guide block 11 that is stopped and guided by the vertical groove and moves up and down is mounted. The guide block 11 includes a horizontal groove 24 into which one end side of the pin 12 that passes through the threading shaft 3 perpendicularly to the upper part of the threading shaft 3 is fitted, and a protrusion 25 that prevents the pin 12 from rotating. A configured guide 13 is provided.

  The threading shaft 3 is fitted with a coil spring 14 that engages the upper end with the pin 12 and the lower end with the guide block 11, and the guide block 11 is pushed down by the action of the coil spring 14 to guide the guide portion 13. The protruding portion 25 is in contact with the pin 12, that is, the threading shaft 3 is not rotated.

  At the lower end of the threading shaft 3, there is provided a threading portion 17 having a collar portion 17 that can be inserted into the needle hole 16 of the sewing needle 15 and an operation lever 18 that is an operating body for pushing down and rotating the threading shaft 3. A hook 30 is attached. 5 is a cross-sectional view of the sewing machine according to the embodiment of the present invention, taken along line VV in FIG. As shown in FIG. 5, the threading hook 30 rotates the guide lever 21 by rotating the operation lever 18, and the hook portion 17 attached to the tip of the guide portion 21 is moved in the direction of the needle hole 16 of the sewing needle 15. Move to rotate.

  Returning to FIG. 3, in order to ensure that the threading to the sewing needle 15 is performed in the vicinity of the top dead center of the sewing needle 15 at the intermediate portion of the threading shaft 3, the threading shaft 3 is lowered by a certain amount or more. A stopper 19 is provided as a restricting mechanism for blocking. The stopper 19 is engaged from above with a support portion 26 that protrudes to the side of the lower end of the shaft support portion 1. In the vicinity of the top dead center, the stopper 19 is positioned several millimeters above the support portion 26. It is supposed to be. Until the stopper 19 comes into contact with the support portion 26 from this position, the height of the collar portion 17 is such that it can be inserted into the needle hole 16 of the sewing needle 15.

  In the present embodiment, as shown in FIG. 2, the upper lever locking portion 33 that can lock the upper thread and cut the excess upper thread is provided on the pressing lever 32 that pushes down the cloth presser. is there. FIG. 6 is a front view showing the configuration of the pressing lever 32 according to the embodiment of the present invention. As shown in FIG. 6, the upper thread locking portion 33 provided on the push-down lever 32 has a guide groove 331 extending obliquely downward so as to guide the upper thread downward when the upper thread is hooked. Yes. At the bottom of the guide groove 331, a coiled spring member 332 is provided as a locking member for locking the upper thread, and a cutter blade 333 is provided as a cutting member for cutting the upper thread.

  Prior to the execution of the threading operation, the threading shaft 3 is pulled up by the action of the spring 10 as shown in FIG. 3, and the stopper 19 is not in contact with the support portion 26 below the shaft support portion 1. And the height of the pin 12 is a height which contacts the protrusion part 25 of the guide part 13, and the threading shaft 3 does not rotate. Thereby, it can prevent beforehand that the collar part 17 rotates carelessly and breaks by contact | abutting with the sewing needle 15 grade | etc.,.

  When performing the threading operation, the sewing needle 15 is positioned near the top dead center, and the operation lever 18 is pushed down against the action of the spring 10. Thereby, first, the projection 23 of the guide block 11 comes into contact with the receiving shelf 6 of the positioning block 5 and stops, and further pushed down against the coil spring 14, the one end side of the pin 12 comes into contact with the receiving shelf 6. In this state, since the pin 12 can be fitted into the horizontal groove 24, the threading shaft 3 can be rotated, and the lever 17 of the threading hook 30 is moved to the sewing needle 15 by rotating the operation lever 18. Can be rotated in the direction of the needle hole 16.

  The threading shaft 3 is lowered until the stopper 19 comes into contact with the support portion 26 below the shaft support portion 1, but cannot be lowered below the contact position. When the stopper 19 is in contact with the support portion 26, the pin 12 of the threading shaft 3 is in contact with the protrusion 25 of the guide portion 13, that is, the threading shaft 3 does not rotate. Therefore, the threading hook 30 does not rotate, and it is possible to prevent the hook portion 17 from being damaged due to contact with the presser foot or the like.

  Since the work from here is the same as FIG. 1 (a) to FIG. 1 (d) for explaining the threading work, the detailed explanation is omitted. That is, the pressing lever 32 is lowered, the cloth presser is pressed down to the lowest point, the handwheel is turned, and the sewing needle 15 is set near the top dead center. In this state, the operations shown in FIGS. 1 (a) to 1 (d) are executed.

  FIG. 7 is a partial perspective view schematically showing a threading operation using the threading device for the sewing machine according to the embodiment of the present invention. FIG. 7 (a) corresponds to FIG. 1 (e), and as shown in FIG. 7 (a), with the upper thread A lightly gripped, the state where the upper thread A is hooked on the collar portion 17 from above is maintained. Then, it is rotated and hooked on the upper thread locking portion 33 provided on the push-down lever 32 as shown in FIG. The upper thread A is guided along the guide groove 331 of the upper thread locking portion 33 to the bottom of the guide groove 331 and is fixed by being sandwiched between the spring members 332. Further, the remaining upper thread B is further cut by the cutter blade 333 provided at the bottom by pushing the upper thread A down to the bottom of the guide groove 331.

  When the excess upper thread B is cut from the state shown in FIG. 7B, the upper thread A is fixed in a state in which a tension similar to the tension applied to the upper thread by the operator's finger support is applied. can do. In this state, when the operation lever 18 is turned counterclockwise when viewed from above, the collar portion 17 of the threading hook 30 passes through the needle hole 16 of the sewing needle 15 while the thread is hooked, and the threading is performed. Executed. When the thread is pulled by the collar portion 17, the upper thread is released from the spring member 332, and the upper thread passes through the needle hole 16 of the sewing needle 15 without fail. Thereafter, when the operation lever 18 is released, the threading shaft 3 is lifted together with the guide block 11 by the action of the spring 10 and returned to the initial position.

  By performing the threading operation in this way, the operator does not need to hold the upper thread during the threading operation, and the threading operation is performed while maintaining an appropriate tension applied to the upper thread. Work can be performed. Therefore, it is possible to provide a threading device that can perform a reliable threading operation without requiring any skill in the operator.

  In the above-described embodiment, the upper thread locking portion 33 is provided on the pressing lever 32. However, the upper thread locking portion 33 is not particularly limited to being provided on the pressing lever 32, and is higher than the collar portion 17. Any position can be used as long as a predetermined tension can be applied to the upper thread. FIG. 8 is a schematic diagram showing the positional relationship between the collar portion 17 and the upper thread locking portion 33.

  As shown in FIG. 8, the upper thread A hooked on the collar part 17 is supported by an upper thread locking part 33 provided at a position that forms a predetermined angle α upward with respect to the horizontal direction. In the example of FIG. 8, the upper thread locking portion 33 is shown on the opposite side of the sewing hole 15 insertion direction from the position of the needle hole 16 of the sewing needle 15.

  As long as the upper thread locking portion 33 can be provided, it is not limited to being provided on the opposite side to the direction in which the sewing product is inserted, and the direction in which the sewing product is inserted, i. Needless to say, the upper thread locking portion 33 may be provided on the side.

  As described above, according to the present embodiment, there is no need to continuously apply the necessary tension with the finger to the upper thread hooked on the collar, and the thread is securely threaded as the collar comes out of the needle hole. In addition, the threaded upper thread is not accidentally pulled out. Therefore, it is possible to reliably perform the threading operation without requiring the operator to be particularly skilled in the operation.

  In addition, various modifications can be added to the above-described embodiment without departing from the spirit of the present invention.

It is a fragmentary perspective view which shows typically the threading operation | work of the conventional sewing machine. It is sectional drawing in the surface of the left-right direction containing the needle bar which shows the structure of the arm part of the sewing machine concerning embodiment of this invention. It is sectional drawing in the surface of the left-right direction containing the needle bar which shows the mounting state of the threading device of the sewing machine which concerns on embodiment of this invention. FIG. 4 is a cross-sectional view of the sewing machine according to the embodiment of the present invention, taken along the line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view of the sewing machine according to the embodiment of the present invention, taken along line VV in FIG. 3. It is a front view which shows the structure of the pressing lever which concerns on embodiment of this invention. It is a fragmentary perspective view which shows typically the threading operation | work using the threading device of the sewing machine which concerns on embodiment of this invention. It is a schematic diagram which shows the positional relationship of a collar part and an upper thread latching | locking part.

Explanation of symbols

1 Shaft support 2 Needle bar 3 Threading shaft (rotating mechanism)
15 Sewing needle 16 Needle hole 17 collar 18 Operation lever (operating body)
19 Stopper (regulation mechanism)
21 Guide part 30 Threading hook 32 Push-down lever 33 Upper thread locking part 331 Guide groove 332 Spring member (locking member)
333 Cutter blade (cutting member)

Claims (4)

A threading shaft that is close to a needle bar that moves the supported sewing needle up and down, can be moved up and down, and is supported so as to be able to rotate around the shaft;
A hook part that can be inserted into the needle hole of the sewing needle, and a guide part that guides the hook part to the needle hole, and the threading shaft is moved in the vertical direction and rotated about the threading axis. A threading hook that is rotatably attached to the lower end portion of the threading shaft as an integral part of the operation body capable of
A regulation mechanism for regulating the lower limit position of the threading shaft;
A threading device for a sewing machine comprising: a turning mechanism for turning the guide portion by a predetermined angle so that the collar portion is inserted into a needle hole of a sewing needle near a lowering limit point of the threading shaft;
With the operating body pushed down the threading shaft to the vicinity of the lowering limit point, and rotating the operating body, the upper thread hooked on the collar is inserted into the needle hole of the sewing needle. A threading device for a sewing machine, comprising: an upper thread locking portion that is held at a position higher than the collar portion until a predetermined tension is applied and that can cut unnecessary upper thread.   2. The threading device for a sewing machine according to claim 1, wherein the upper thread locking portion is provided on a side opposite to a direction in which the workpiece is inserted with respect to a position of the needle hole of the sewing needle.   3. The threading device for a sewing machine according to claim 1, wherein the upper thread locking portion is provided in a pressing lever that presses down a cloth presser that presses the workpiece.   The upper thread locking portion includes a guide groove for guiding the upper thread, and has a locking member for locking the upper thread and a cutting member for cutting the upper thread at the bottom of the guide groove. The threading device for a sewing machine according to claim 3.

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