JP2586732Y2 - Sewing machine threading device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a threading device for a sewing machine. In particular, the knob is depressed to position a hook at the tip at the same level as a thread hole of a needle. The present invention relates to a threading device for a sewing machine in which a needle thread is hooked at a hook portion to perform threading to a needle by operation.

[0002]

2. Description of the Related Art In a threading device of a sewing machine, a knob is turned down while lowering the hook portion by pushing down the knob, and when the knob is pushed down to the lowermost end, the hook portion is passed through the thread hole of the needle. Is released, the hook is moved back along the above-mentioned path by the action of a spring, and the above-mentioned type is operated in which the knob is pushed down to reciprocate horizontally. Of these, the latter type requires an operation of pushing down the knob and an operation of horizontally reciprocating rotation, but has an advantage that the thread can be reliably pulled out from the thread hole of the needle and threading can be reliably performed.

[0003] Japanese Utility Model Publication No. 55-34067 discloses the latter type, in which a holder is fixed to a needle bar, and is slidably and rotatably supported in parallel with the needle bar, and is always lifted upward by a spring. A pin is protruded sideways on the support shaft that is urged to be pushed, a knob is protruded, and a hook is provided at the lower end, and the knob is pushed down to move the pin to the engaging portion of the holder. A threading device has been proposed in which, when the knob is rotated after being engaged, the hook portion is passed through the thread hole of the needle.

[0004]

In the above-described threading device, the support shaft can rotate only when the hook is at the same level as the thread hole of the needle. If the level of the yarn hole does not become the same level,
The movement of the pin is hindered by a guide wall projecting upward from the holder, whereby the support shaft cannot rotate and the hook portion engages with a needle or the like to prevent damage. In order to prevent the rotation of the support shaft until the level of the hook portion becomes the same level as the level of the needle hole, the guide wall must be extended considerably long in the vertical direction until the level of the hook portion becomes the same as the level of the needle thread hole. It is not preferable from the viewpoint of inertia to attach such a long member to the needle bar which moves up and down at high speed.

In addition, the above-mentioned structure of the holding member is not preferable because it is too bulky in the narrow and limited space of the needle bar driving mechanism, and the support shaft can be moved up and down and positioned, and furthermore, can be rotated only at a predetermined level. It is desirable that the mechanism for this purpose be as compact as possible because it has a degree of freedom in design. The present invention has been made in view of the above points, and has a compact mechanism for allowing the support shaft to move up and down and to be positioned, and further, to be able to rotate only at a predetermined predetermined level. An object of the present invention is to provide a threading device for a sewing machine that has a degree of freedom and that has a compact member attached to a needle bar and reduces adverse effects on inertia.

[0006]

A threading device for a sewing machine according to the present invention is supported so as to be vertically movable and rotatable in parallel with a needle bar.
A support shaft provided with a pin protruding laterally at an upper portion, a first spring for urging the support shaft to always be pulled upward, and mounted on the support shaft and guided by guide means to the support shaft A guide block that moves up and down along with a horizontal part and a horizontal part that is formed on the guide block and guides the horizontal rotation of the pin about the support shaft,
A second guide that is mounted on a support shaft, and has a lower end engaged with the guide block and an upper end engaged with the pin, and pressing the guide against the pin; And a positioning member fixed to the needle bar for positioning the guide block, an operation lever provided on the support shaft, and a hook portion supported at the lower end of the support shaft and capable of being inserted into an eye hole of the needle. You.

[0007] In this device, the threading of the needle is performed as follows. When the operation lever is pushed down and the support shaft is lowered, the guide block pressed against the pin by the locking portion by the action of the second spring is lowered integrally with the support shaft. After the guide block is locked to the positioning member and its movement is stopped, if the operating lever is still pressed down, the pin compresses the second spring and descends together with the support shaft. At the time when the pin is disengaged by the locking portion of the guide portion where the pin is fitted, the hook portion is at the same level as the eye hole of the needle. In this state, when the operation lever is rotated in one direction, the pin is moved to the horizontal portion of the guide portion. The hook is rotated together with the support shaft, and the hook is inserted into the eye of the needle. When the operation lever is moved backward after the insertion, the hook portion catches the thread, exits from the eye of the needle, and causes the loop of the thread to protrude from the eye. Then, when the operating lever is released, the guide block is pressed down against the support shaft by the action of the second spring, and the pin is fitted and locked in the locking portion, and the support shaft is operated by the action of the first spring. Rises.

In a state where the pin is fitted and locked in the locking portion, the guide block is lowered and positioned by the positioning member, and then the pin is released from the locking portion, and the hook portion is at the same level as the eye hole of the needle. Since the hook cannot rotate, the hook does not engage with a needle or the like and is not damaged. Further, since the positioning member attached to the needle bar only needs to have a function of engaging with the guide block, the structure can be simplified and the structure can be made compact. It is only necessary to have a function of preventing rotation of the pin fitted to the locking portion of the guide portion, so that the locking portion can be shortened, and thus the guide block can be made compact.

In the above-described device, the positioning of the hook portion, that is, the level of the eye hole of the needle is matched with the engagement of the guide block with the positioning member, and the engagement of the pin with the horizontal portion by the action of the second spring. It is performed by engagement,
To facilitate positioning, it is desirable to extend the pin and project it to the opposite side so that the extended projecting end can be engaged with the positioning member. In this case, when the operating lever is pressed down, the guide block first engages with the positioning member, and then the protruding end of the pin engages with the positioning member, preventing the support shaft from being lowered and positioning the hook. As a result, the hook can be positioned by simply pushing the operating lever down to the limit. Further, by projecting the pins on both sides of the support shaft, the second spring is pressed at two symmetrical positions, so that the spring can be stably supported without being lifted up.

In order to allow the hook to rotate horizontally with the hook positioned, that is, to allow the protruding end of the pin to engage with the positioning member and rotate horizontally, the positioning is performed. The member must have a flat engagement surface. When positioning is performed by extending the pin and engaging the opposite protruding end with the positioning member, when the pin separates from the locking portion and rotates, It is more preferable to provide a protrusion that protrudes horizontally with a certain interval from the engagement surface on the side, and to form a groove so that the protrusion end extending between the engagement surface and the protrusion is fitted. . In a state in which the extending protruding end is fitted into the groove, the elevation of the support shaft due to the action of the first spring is regulated by the positioning member. Therefore, the operating lever must not be pressed against the action of the first spring. Even so, the hook portion can be maintained at the same level as the eye hole of the needle, so that the thread can be threaded through the needle simply by rotating horizontally after pressing the operating lever to the limit. .

It is desirable that the threading of the needle is performed at or near the top dead center of the needle located above the presser foot when the presser foot is raised. For this purpose, a stopper is provided on the support shaft, and when the stopper hits the bearing that supports the support shaft and is prevented from descending, the hook is positioned at the level of the eye hole of the needle located at or near the top dead center. It is advisable to set the mounting position of the stopper.

[0012]

FIG. 1 shows a threading device for a zigzag sewing machine. A needle bar 2 and a support shaft 3 are supported on a support frame 1 which is swung left and right with an upper end serving as a fulcrum.
It is connected to a main shaft (not shown) via a crank and a rod, and moves up and down by rotation of the main shaft.
A positioning block 5 as a positioning member is fixed directly above the needle bar holder 4, and the positioning block 5 has a receiving shelf 6 protruding laterally at a lower portion on a side opposite to the support shaft 3, and a receiving shelf 6 above the receiving shelf. At the center of the upper part, a projection 8 is formed which protrudes slightly to the side and forms a groove 7 into which a pin to be described later can be fitted.

On the other hand, the support shaft 3 is urged by a first spring 10 so as to be always pulled up, and the upper portion thereof is fitted in a vertical groove 9 as a guide means formed in the support frame 1 by fitting. A guide block 11 that is stopped from rotating and moves up and down while being guided by the vertical groove 9 is mounted. The guide block 11 has a pin 12 that penetrates above the support shaft at right angles to the support shaft 3 (the other side is in A horizontal groove 13a to which one side is fitted, and a pin 1 formed at the upper part of the horizontal groove.
There is provided a guide portion 13 including a recess 13b as a locking portion for fitting and locking 2 with. The support shaft 3 has the upper end engaged with the pin 12 and the lower end engaged with the guide block 11 .
A coil spring 14, which is a second spring, is mounted, and the guide block 11 is pressed down by the action of the spring 14, so that the guide portion 13 is pressed against the pin 12.

The support shaft 3 also has an eye hole 1 for a needle 15 at the lower end.
6 has a hook portion 17 that can be inserted therethrough, and further has a foldable operation lever 18 for pushing down and rotating the support shaft 3, and a threading for a needle is provided at an intermediate portion. In order to perform the operation at the top dead center of the needle, a stopper 19 for preventing the support shaft 3 from lowering by a certain amount or more is provided, and the stopper 19 is engaged with a support portion 1a projecting laterally at the lower end of the support frame 1 from above. When the lowering of the support shaft 3 is prevented, the level of the hook portion 17 matches the eye hole 16 of the needle 15 located at the top dead center.

This device is constructed as described above. When the normal threading operation is not performed, as shown in FIGS. 1 and 3, the support shaft 3 is pulled up by the action of the spring 10, and the stopper 19 is moved to the support frame. The positioning block 5 is held so as to be engaged with the support 1b at the intermediate portion from below, so that the positioning block 5 does not contact the guide block 11 even when the needle bar 2 moves up and down. Then, one side of the pin 12 is fitted and locked in the recess 13b, and the rotation of the support shaft 3 is stopped (FIG. 4).
7 is held in a state as shown in FIG. 5 and is rotated inadvertently, so that it is not damaged by hitting a needle or the like.

When performing threading, when the needle 15 is located at the top dead center, the operating lever 18 is pressed down against the action of the spring 10. Thereby, first, the guide block 11 hits the receiving shelf 6 of the positioning block 5 and its movement is stopped (FIG. 6). Then, the other side of the pin 12 hits the receiving shelf 6, and the stopper 19 hits the support part 1a to lower the support shaft 3. Is stopped, and one side of the pin 12 is separated from the recess 13b (FIG. 7).

When the operation lever 18 is pushed down to the limit and the operation lever 18 is turned clockwise in FIG.
Then, the other side fits into the groove of the positioning block 5 and turns horizontally (FIGS. 2, 8 and 9), and the hook 17 is inserted into the eye 16 of the needle 15 (FIG. 10). When the operation lever 18 is rotated counterclockwise in FIG. 10 after the insertion, the hook portion 17 hooks the thread and slips out of the eye 16 of the needle 15, and
When the operating lever 18 is released from the state shown in FIG. 1, one side of the pin 12 is located below the recess 13 b and the other side is separated from the groove 7.
1 is pushed down, one side of the pin 12 is fitted and locked in the recess 13b, and the support shaft 3 is raised by the action of the spring 10 together with the guide block 11 until the stopper 19 contacts the support portion 1b. It is returned to the position shown.

[0018]

[Effects of the Invention] The present invention is configured as described above, and has the following effects. According to the threading device of the first aspect, the thread hooked by the hook portion can be reliably passed through the eye hole of the needle by the rotation operation of the operation lever, and the threading can be reliably performed. Since the pin is fitted and locked in the locking portion, the rotation of the support shaft is prevented, and the hook cannot be rotated. Therefore, the hook is not damaged by being engaged with a needle or the like. since member may have a function of guide block prevents its descent engaged, Turkey can be configured to the structure is simple compact
And the guide block having the guide portion is fitted with the pin
It is sufficient that the locking portion has a function of only stopping the rotation of the pin
The locking part can be shortened, so that the needle bar
The attached guide block can be made compact.
Since the influence of inertia can be reduced because of this, the locking portion of the guide portion only needs to have a function of preventing rotation of the fitted pin, so the locking portion can be shortened, and therefore the guide portion can be shortened. The provided guide block can also be made compact, and has an effect such as being able to have a degree of freedom in design in combination with a positioning member that can be made compact.

In the threading device according to the second aspect of the present invention, the hook is held at the same level as the eye hole of the needle only by pressing down the operating lever until the protruding end of the pin comes into contact with the engaging surface of the positioning member. Positioning of the part can be easily performed. As in the threading device according to the third aspect, if the protruding end of the pin is fitted into the groove at the time of threading so that the vertical movement of the support shaft with respect to the needle bar can be prevented, the operation lever can be pressed down. The hook can be inserted into and removed from the eye hole of the needle by simply rotating horizontally, without having to do anything.

If the stopper is provided on the support shaft as in the threading device according to the fourth aspect, the threading is performed only at or near the top dead center of the needle, and the hook cannot be further lowered. Therefore, it will not be damaged by hitting the presser foot or the like.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a threading device according to the present invention provided in a needle bar mechanism of a zigzag sewing machine, showing a state where threading is not performed.

FIG. 2 is a perspective view of the same device when performing threading.

FIG. 3 is a front view of the device when threading is not performed.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a sectional view taken along line BB of FIG. 3;

FIG. 6 is a front view of the threading device showing a state where the guide block hits the positioning block and stops its movement during threading.

FIG. 7 is a front view of the device, showing a state where the pin is detached from the locking portion and the hook portion is positioned at the level of the eye hole of the needle.

FIG. 8 is a front view of the same device, showing a state where the hook portion is inserted into an eye hole of the needle.

FIG. 9 is a sectional view taken along the line CC of FIG. 8;

FIG. 10 is a sectional view taken along line DD of FIG. 8;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Support frame 2 ... Needle bar 3 ... Support shaft 5 ... Positioning block 6 ... Receiving shelf 7 ... Groove 9 ... Vertical groove 10 ... Spring 11 ... Guide block 12: Pin 13a: Horizontal groove 13b:
Depression 14 ... Coil spring 15 ... Needle 17 ... Hook 18 ... Operation lever 19 ... Stopper

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) D05B 87/02

Claims (4)

(57) [Scope of request for utility model registration] 1. A support shaft, which is vertically and rotatably pivotally supported in parallel with a needle bar, and has a pin provided on an upper portion thereof so as to protrude laterally, and biases the support shaft to always be pulled upward. A first spring, a guide block mounted on the support shaft and guided by the guide means to move up and down along the support shaft, and a horizontal rotation of the pin formed on the guide block and centering on the support shaft And a guide portion formed upward from the end of the horizontal portion and the horizontal portion, the locking portion engaging and locking the pin, and the guide portion mounted on the support shaft and formed on the guide block to the pin. A second spring to be pressed and fixed to the needle bar,
A positioning member for positioning the guide block, an operation lever provided on the support shaft, and supported by a lower end of the support shaft,
A threading device for a sewing machine comprising a hook portion that can be inserted into an eye of a needle. 2. The pin is extended and protrudes to the opposite side, and can be engaged with a positioning member at an extended protruding end, and the pin can be engaged with the positioning member and can be rotated horizontally. 2. The threading device for a sewing machine according to claim 1, wherein the flat engagement surface is formed. 3. A groove is formed on one side of the engaging surface so that a protruding portion is formed at a predetermined interval from the engaging surface and a protruding end of the pin can be fitted between the engaging surface and the engaging surface. The threading device for a sewing machine according to claim 2, wherein 4. The threading device for a sewing machine according to claim 1, wherein the support shaft is provided with a stopper for performing threading at or near the top dead center of the needle.