JP2936203B2 - sewing machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a sewing machine provided with a looper and a crochet that can move up and down so as to sew a cloth by moving the crochet up and down.

[Conventional technology]

In this type of sewing machine, by changing the direction of the crochet with respect to the moving direction of the cloth and the rotation angle of the looper, loop sewing and loop sewing are performed on the cloth with a single sewing machine. (See, for example, JP-A-59-150156).

[Problems to be solved by the invention]

In this type of sewing machine, if the resistance to pulling out the thread is weakened in order to sufficiently increase the height of the loop on the cloth surface, the loop will be high but the chain stitch will be loosened. On the other hand, if the drag is increased to perform the chain stitching in a state where the thread is tight, the height of the loop becomes shorter. Therefore, in the case of forming an embroidery pattern by combining the loop stitching and the chain stitching, there is a problem that the difference between the heights of the two is only small, and thus the pattern feels blurred.

The present invention has been made in order to solve the above-mentioned problems (technical problems) of the prior art, and interlocks a drag force applied to a thread drawn by a crochet with a tension applied to the drawn thread in an interlocking manner. To provide a sewing machine capable of changing the strength, performing tall loop stitching and sufficiently tightened chain stitching, and forming an embroidery pattern with a distinctive difference between the two. It is intended for.

[Means for solving the problem]

In order to achieve the above object, the present invention employs the means described in the claims, and the operation is as follows.

[Action]

In the case of loop stitching, the drag given by the thread tensioner to the pulled-out thread is reduced, and the tension given to the pulled-out thread by the tension member is reduced in an interlocking manner. By performing sewing in this state, when the crochet is raised, the thread is pulled up with little resistance, and when the crochet is lowered, the pulled up thread is prevented from being pulled back from the cloth,
As a result, a tall loop can be formed. On the other hand, in the case of chain stitching, the above-described drag and tension are increased in an interlocking manner. By performing sewing in this state, when the crochet is raised, the thread can be sufficiently tightened, and when the crochet is lowered, the tightened state can be maintained.

〔Example〕

Hereinafter, drawings showing an embodiment of the present application will be described. First
In the figure, reference numeral 1 denotes a bed in a sewing machine, which is provided with a needle plate 2. Reference numeral 3 denotes a well-known looper provided rotatably in a horizontal plane below the needle plate 2, and reference numeral 4 denotes a crochet provided vertically movable above the needle plate 2. Reference numeral 5 denotes a thread tension device provided below the bed 1. Hereinafter, the thread tension device 5 will be described in detail with reference to FIG. 2 and FIG. Reference numeral 10 denotes a base frame which is mounted on a frame of the sewing machine. Reference numeral 11 denotes a thread tension base attached to the base frame 10 for giving a resistance to the thread pulled by the crochet 4. Reference numeral 12 denotes a tension member similarly attached to the base frame 10 for applying tension to the yarn pulled out through the yarn tensioner 11. 13
Denotes an operating mechanism for operating the thread tensioner 11 and the tension member 12 in an interlocked manner.

The thread tensioner 11 has a structure equivalent to that of a known thread tensioner (for example, Japanese Utility Model Publication No. Sho 53-6611) capable of changing the strength of the drag applied to the thread pulled by the crochet 4.
5, 16 are thread tension dishes, 17 is a pressing spring for pressing the thread tension dish 16 against the thread tension dish 15, 18 is an adjustment for adjusting the pressing force, that is, 19 is a thread tension dish 16 The loosening rods to separate from 15 are shown.

Next, the tension member 12 will be described. Reference numeral 21 denotes a spring arm, also referred to as a thread take-up spring, the base of which is pivotally attached to the base frame 10 by a pivot piece 22 such as a pin. twenty three
Denotes a threading ring provided at the free end of the spring arm 21. Reference numeral 24 denotes an operation arm integrally formed with the base of the spring arm 21. 25 is the base frame
The thread guide attached to 10 serves to orient the thread reaching the tension member 12 so that tension can be applied.

Next, the operation mechanism 13 will be described. Reference numeral 27 denotes a reciprocally rotatable operation shaft. Reference numeral 28 denotes a cam mounted on the operation shaft 27. The loosening bar 19 is opposed to the cam, and as shown in FIG. 3 and FIG. The loosening rod 19 is moved forward and backward. 29 cams the tension member 12
The linking mechanism for linking to 28 is shown. Reference numeral 30 denotes a cam lever of the mechanism, which is pivotally attached to a bracket 31 attached to the base frame 10 by a pivot piece 31a. Reference numeral 32 denotes a driven piece provided at one end of the cam lever 30, which is in contact with the cam.
Reference numeral 33 denotes an engaging portion provided at the other end of the cam lever 30. Reference numeral 34 denotes a transmission piece provided along the side surface of the base frame 10, and the guide pieces 35, 35 attached to the base frame 10 guide the movement in the vertical direction in FIGS. Reference numeral 36 denotes an engaging portion of the transmission piece, which is in contact with the engaging portion 33. Reference numeral 37 denotes an operation portion provided at the other end of the transmission piece 34, which is formed in the form of a through hole, and through which the operation arm 24 of the tension member 12 is inserted. Numeral 38 denotes an urging spring for applying an urging force to the transmitting piece 34 so that the engaging portion 36 always contacts the engaging portion 33. A driving device 40 shown in FIG. 1 is used for reciprocatingly rotating the operation shaft 27. For example, a geared motor is used. 41 to 43 are members provided for detecting the rotation position of the operation shaft 27 in order to automatically control the rotation thereof, 41 and 42 are sensors, 43 is an operation piece attached to the operation shaft 27, The sensor 41 or 42 is operated interchangeably. 44 is a control device for controlling the driving device 40. 45 is a thread tensioner additionally provided. 46 is a yarn sensor for detecting the presence or absence of a yarn, for example, a micro switch is used.

Next, the operation of the sewing machine having the above-described configuration when sewing (embroidery sewing) is performed on the cloth 51 on the needle plate 2 with the threads 52 and 53 will be described. Threads 52 and 53 are examples of using different colored threads or different types of threads to enhance the finish of embroidered products. If so, only one of them is used.

First, a case where loop sewing as shown in FIG. 4 is performed on the cloth 51 will be described. In this case, the driving device 40 rotates the cam 28 to a position as shown in FIG. As a result, the thread tensioner 11 is pushed by the loosening bar 19 to be in a state as shown in the figure. In addition, the transmission piece 34 is located at the lowered position via the cam lever 30, and the spring arm 21 is at the position indicated by reference numeral a1 in FIG. 2 when no force is applied to the threading ring 23. In this state, the loop 54 is formed as shown in FIG. 4 by the rotation of the looper 3, the vertical movement of the crochet 4, and the movement of the cloth 51 in the direction of the arrow shown in FIG. In the case of this sewing, the crochet 4
In the process of lifting the yarns 52 and 53 by hooking the yarns 52 and 53, no drag is applied to the yarns 52 and 53 pulled by the crochet 4 with respect to the pulling-out by the thread tensioner 11, and the weak drag is provided only by the thread tensioner 45. Is provided. Because of this,
The threads 52, 53 are then pulled lightly. In this process, the spring arm 21 applies a slight tension corresponding to the amount of bending to the yarn pulled out through the thread tensioner 11 due to a slight bending from the position of a1 to the position of a3. Meanwhile, crochet 4
During the downward movement of the thread 51, the threads 52, 53 between the cloth 51 and the thread tensioner 11 are kept taut by the tension given by the spring arm 21. In this case, since the tension is weak enough to match the slight bending of the spring arm 21 from the position of a1 to the position of a2 or a3 in FIG. Is prevented from being pulled back. Therefore the fourth
As shown in the drawing, the formation of the loop 54 having a sufficient height is smoothly performed. In FIG. 2, a3 indicates a state in which the spring arm 21 is deflected in the process of raising the crochet 4, and a2 indicates a state in which the spring arm 21 has returned slightly in the process of lowering the crochet 4.

Next, the case of performing the chain stitching as shown in FIG. 7 will be described with reference to FIGS. In this case, the driving device 40 rotates the cam 28 to the position shown in FIG. Therefore, as shown in the figure, the thread tension device 11 is
And the yarn is brought into a state of giving a drag force to the yarn. Further, the transmission piece 34 reaches the ascending position as shown in the drawing via the cam lever 30, and the spring arm 21 of the tension member is brought to a state where it is present at the position b1 when no force is applied to the threading ring 23. You. By performing sewing in this state, the yarns 52 and 53 pulled by the rise of the crochet 4 are provided with a large resistance by the two thread tensioners 11 and 45. Also, since the operation is performed in a state where the spring arm 21 is greatly bent from the state shown by the reference numeral b1 to the state shown by the reference numeral b2 or b3, even when the crochet 4 descends, the thread tension device 11 and the crochet 4 A large tension is applied to the intervening yarn. Since sewing is performed in such a thread tension state, ring sewing is performed in a state where the threads 52 and 53 are firmly tightened. In FIG. 5, reference characters b2 and b
Reference numeral 3 corresponds to reference numerals a2 and a3 in FIG. 2, respectively.

Next, FIG. 8 shows a different embodiment of the present invention, in which the strength of the drag against the pull-out given to the yarn can be changed in three stages, and this is linked with the change in the strength of the tension by the tension member. This is an example. In the figure, a thread tensioner 45e having the same configuration as the thread tensioner 11e is used. A sub-operation shaft 61 that rotates in conjunction with the operation shaft 27e is provided, and the loosening bar 19e of the thread tensioner 45e is operated by a cam 62 attached thereto.

In this configuration, as shown in the following Table 1, depending on the rotational positions of the cams 28e and 62, the roux stitching and chain stitching can be performed in the same state as in the previous embodiment,
When the embroidery frame on which the cloth is stretched is largely moved, for example, to change the pattern forming position, both of the thread tension devices 11e and 45e are released so that the thread can smoothly follow the movement. be able to.

In addition, functionally considered to be the same or equivalent to those in the previous figure, the same reference numerals as those in the previous figure denote the same parts as in the previous figure.
And duplicated description is omitted.

(Also, in the following figure, the letter f is added in the same way and duplicate explanation is omitted.) Next, FIG. 9 shows still another embodiment of the present invention.
The ratio of the rotation angles of the operation shaft 27f and the sub operation shaft 61f is 2: 1.
The following shows an example of interlocking such that cams 28f and 62f are used in each of loop stitching, chain stitching, and frame movement.
Are rotated to the positions shown in the drawing.

〔The invention's effect〕

As described above, in the present invention, a large number of loops
In the case where the crochet 54 is formed, the drag against the withdrawal of the thread 52 can be reduced and the tension on the withdrawn thread 52 can be reduced in conjunction with it. The thread 52 can be sufficiently pulled up from 51, and when the crochet 4 is lowered, the pulled-up thread 52 can be prevented from being pulled back by tension, so that a tall loop 54 can be formed.

In the case of chain stitching, the above-mentioned hole force can be increased and the above-mentioned tension can be increased in conjunction therewith.
When the crochet 4 is lowered, the tightened state of the thread 52 can be maintained, and the thread 52 can be tightened to perform chain stitching.

These things, for example, many loops on the cloth surface
In the case of the formation of an embroidery pattern in which the periphery of the surface on which 54 is formed is trimmed by chain stitching, the height difference between the "high" of the loop 54 and the "low" of the chain stitch is prominent, and a pattern with a lip is formed. There is an advantage that can be formed.

[Brief description of the drawings]

1 is a perspective view, FIG. 2 is a partially cutaway front view showing a state of a thread tension device when performing loop stitching, and FIG. 3 is a sectional view of FIG. FIG. 4 is an enlarged sectional view showing a state of loop stitching on a cloth; FIGS. 5 and 6 are views similar to FIGS. 2 and 3 showing a state of chain stitching; FIG. 7 is an enlarged sectional view showing a state of chain stitching on a cloth, FIG. 8 is a right side partial view showing a different embodiment, and FIG. 9 is a view showing a further different embodiment (operation explanatory diagram). 2 ... needle plate, 3 ... looper, 4 ... crochet, 11 ... thread tensioner, 12 ... tension member, 13 ... operating mechanism.

Continuation of front page (56) References JP-A-61-206482 (JP, A) JP-A-52-76155 (JP, A) JP-A-58-46987 (JP, A) JP-A-59-150156 (JP, A) , A) JP 40-27957 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB name) D05C 15/00-15/38 D05B 47/02

Claims (1)

(57) [Claims] 1. A looper is provided below the needle plate, while a crochet which is movable up and down is provided above the needle plate,
In a sewing machine in which sewing is performed on a cloth on the needle plate by a thread pulled out by the crochet due to the vertical movement of the crochet, a thread tensioner for giving a drag force to the thread drawn by the crochet against pulling out. And a tension member capable of changing the strength of the drag, the tension member being a tension member for applying tension to the yarn drawn through the thread tension device, and capable of changing the strength of the yarn. A sewing machine characterized in that the thread tensioner and the tension member are provided with an operation mechanism for switching between the strength and the resistance of the thread tensioner and the tension member.