JPS6022921Y2 - Stitch width expansion device on sewing machine - Google Patents

Description

[Detailed description of the invention] The present invention relates to a casting width expanding device for a sewing machine, and in particular, the upper shaft rotates at a speed of 172 times that of the lower shaft, and the relative rotational phase between the upper shaft and the lower shaft is variable. A hook-type decorative stitch sewing machine is configured so that the rotational phase of the upper shaft relative to the hook can be automatically adjusted by controlling the upper shaft, and the direction of the needle hole of the needle attached to the needle bar is always aligned. This relates to a cast width expanding device for a sewing machine that is configured to be orthogonal to the motion trajectory of the casting machine, and its purpose is to
In principle, by providing a sewing machine that can expand the casting width by a dimension roughly equivalent to the diameter of the trajectory of the streak light, we can increase the commercial value of the sewing machine by making it possible to perform wide-width sewing with a wide range of variations. This is a significant increase.

Traditionally, zigzag sewing machines have often used so-called fixed hooks in which the hook rotates in a fixed position due to various advantages, but in this type of sewing machine, when vibration is applied to the needle, the needle drop point of the needle relative to the hook moves. However, even if the needle hook crossing condition is appropriately set near a certain needle drop point, when the amplitude of the needle exceeds a certain limit, it becomes impossible for the hook point to capture the thread loop.

Therefore, conventionally there was a limit to the casting width that could be sewn.

In other words, in the conventional fixed hook type zigzag sewing machine,
There is a certain relationship between the amount of vertical displacement of the needle bar and the rotational phase of the hook, so when an amplitude is applied to the needle bar, the intersection conditions between the needle and the hook change depending on the needle drop point. As shown in Figure 2, especially in the fixed hook type and vertical hook type, at the center needle drop point M of the needle amplitude, the amount of rise of the needle from the bottom dead center δM as the needle hook intersection condition is set to the optimum value for the hook tip to capture the thread ring. When set, the needle rise amount δR becomes larger than the optimum value at the right needle drop point, and the needle rise amount δL becomes smaller than the optimum value at the left needle drop point.

Therefore, when attempting to increase the needle amplitude even further, the crossing conditions at the left and right needle drop points will deteriorate, and the uncertainty in catching the thread loop due to such poor crossing conditions will cause skipped stitches, thread breaks, etc. As a result, it became impossible to sew, and there was a limit to the casting width that could be sewn.

Conventionally, various types of sewing machines have been proposed in which the relative phase between the needle bar and the hook is changed to achieve good crossing conditions at each needle drop point in order to expand the casting width of the above-mentioned vertical hook type sewing machine. However, the trajectory of the movement of the striped light forms an arc in a plane parallel to the swinging plane of the needle bar, whereas the trajectory of movement at each needle drop point at the bottom dead center of the needle bar is approximately horizontal. The amount of rise of the needle from the bottom dead center when crossing the hook becomes smaller at the left and right needle drop points as the amplitude of the needle bar increases. Since the stripe intersects the upper thread loop diagonally with respect to the plane formed by the upper thread loop and the needle, there is a structural limit to the casting width that can be expanded depending on the type of hook. Ta.

As a result of studies in view of the above-mentioned problems, the present invention is designed to automatically adjust the rotational phase of the upper shaft relative to the hook in a sewing machine using a horizontal hook by controlling the upper shaft. The needle hole of the needle attached to the needle bar is configured so that the direction is always perpendicular to the trajectory of movement of the light stripe.In principle, the casting width is expanded to a dimension roughly equivalent to the diameter of the trajectory of the light stripe. This is what I did to get it.

The present invention will be explained below with reference to an embodiment. In Fig. 2, 1 is an upper shaft of a sewing machine, 2 is a flywheel, and 3 is a gear device. A pair of intermediate gears 7 and 8 are pivotally connected to an arm shaft 6 fixed to the upper shaft 1, and mesh with the drive gear 4; an adjusting gear 9 is pivotally connected to the upper shaft 1; Gear 9a
and a control gear 11 which meshes with the gear and is fixed to a rotating shaft 10a of a step motor 10 which is a needle bar amplitude imparting device.

Thrust stop links 12 and 13 are fixed to the upper shaft 1 by screws 14 and 15, respectively.

16 and 17 are thrust stop links for intermediate gears 7 and 8, respectively.

Next, referring to Fig. 3, 18 is an amplitude rod, and the rotation axis 1
One end is pivotally connected via a pin 20 to an amplitude rod drive link 19 fixed to 0a, and the other end is a swingable needle bar support 2.
1 via a pin 22.

23 is a needle bar crank fixed to the upper shaft 1; 24 is a needle bar crank pin fixed to the needle bar crank; 25 is a needle bar crank rod, the upper end of which is pivotally connected to the needle bar crank pin; A pin portion 26a of the needle bar holder 26 is rotatable and is held slidably in the longitudinal direction of the pin portion.

A needle bar 27 is inserted into the tip portion 26b of the needle bar holder 26, and the needle bar holder is fixed in the vertical direction by a guide piece 30 and a link 31 fixed to the needle bar 27 with screws 28 and 29, respectively. The needle bar 27 is pivotally held in a regulated position.

The guide piece 30 has two forked ends and is configured to sandwich the guide portion 21a of the needle bar support 21 so that the relationship of the needle bar 27 projected onto the horizontal plane with respect to the needle bar support 21 is always maintained constant. ing.

Furthermore, since the swing shaft 32 of the needle bar support 21 is arranged in line with the hook shaft 34, which is the rotation axis of the hook 33, the needle hole of the needle 35 attached to the needle bar 27 is oriented in the same direction. As shown by the arrow in Fig. 4, the movement locus B of the striped light 33a of the pot 33 is
It is configured to be orthogonal to

36 is a needle stopper.

When the step motor 10 is in a state where no amplitude is applied to the needle bar 27 (center needle drop point M of the needle 35 in FIG. 4), the step motor 10 changes the needle position via the amplitude rod drive link 19 and the amplitude rod 18. The adjustment gear 9 is held in a certain fixed position via the control gear 11 while detecting the signal from the position detector 49, that is, in such a manner that the needle 35 and the striped light 33a intersect with each other in a proper phase relationship. There is.

When applying an amplitude to the needle 35 from this state, in this embodiment, the microcomputer is operated based on the data in the electronic storage device, and the step motor 10 is activated by the amplitude rod drive link 1.
9 is rotationally controlled to obtain a desired needle bar amplitude, and the rotation amount related to the needle bar amplitude is applied to the adjustment gear 9 that meshes with the control gear 11, so that the rotational phase of the upper shaft 1 of the sewing machine with respect to the hook 33 is automatically adjusted. The adjusting waist needle 35 and the striped light 33a are configured to always meet an appropriate crossing condition.

37 is a sewing machine motor, and a drive shaft 37a of the motor includes a motor pulley 38, a timing belt 39, and a lower shaft pulley 40.
The lower shaft 41 is driven through the rotor, and the hook 33 is rotated via a gear 42 and a gear 43 fixed to the hook shaft 34.
Sprocket 44, timing belt 45, drive gear 4
sprocket part 4a, drive gear 4, intermediate gears 7 and 8
The upper shaft 1 is also driven at half the speed of the lower shaft 41 via the arm 6.

46 and 47 are lower shaft bushings, respectively, and 48 is a hook shaft bushing.

In the embodiment of the present invention, the rotational phase of the upper shaft 1 with respect to the lower shaft 41 is controlled by particularly controlling the upper shaft 1. The reason for this is that the method of controlling the upper shaft 1 as in this embodiment Compared to a system in which the lower shaft 41 is controlled, in a sewing machine of the type in which the upper shaft 1 rotates at 1/2 the speed relative to the lower shaft 41, such as the sewing machine according to this embodiment, This is because it is superior in ease of control and reliability due to differences.

Next, the operation of the embodiment of the present invention will be explained.

When no amplitude is applied to the needle bar 27, the pulse motor 10 causes the amplitude rod drive link 19 to position the needle 35 at the M position in FIG. control gear 11
Due to the action of (Fig. 2), the relationship between the rotational phase of the hook and the amount of rise of the needle becomes the relationship shown by NM in Fig. 5, and the needle 35 and the stripe 33a intersect at the amount of rise δ of the needle, resulting in good sewing. It is done.

When an amplitude is applied to the needle bar 27 and the needle 35 is positioned at the R or L position, the relationship between the rotational phase of the hook and the amount of rise of the needle becomes the relationship shown by NR or NL in FIG. 5, respectively. The light 33a intersects with the needle by an amount of rise δ, so that good sewing is performed.

Furthermore, even if the amplitude is applied to the needle bar 27, a good crossing condition can be obtained in the same way as above, and the direction of the needle hole is always perpendicular to the movement locus B of the striped light 33a, so in principle, the amplitude of the needle that can be used for sewing is The amount can be expanded to a size approximately corresponding to the diameter of the motion locus B of the striped light 33a.

As described above, the present invention provides a sewing machine that can increase the stitching width by a dimension approximately corresponding to the diameter of the trajectory of the movement of the striped light, making it possible to perform a variety of wide-width stitches, etc. , which can significantly increase the commercial value of sewing machines, is a device with remarkable effects.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the needle and hook intersection conditions in a conventional sewing machine with a fixed hook type and vertical hook type, Figs. FIG. 3 is a cross-sectional view showing the main part of the A-A cross section in FIG. 2, FIG. 4 is a diagram showing the direction of the needle hole at each needle drop point, and FIG. It is a figure which shows the needle hook intersection condition in . 1 is an upper shaft, 3 is a gear device, 10 is a needle bar amplitude imparting device, 1
0a is the rotation axis, 11 is the control gear, 18 is the amplitude rod, 1
9 is an amplitude rod drive link; 21 is a swinging needle bar support;
22 is a needle bar, 33a is a stripe, 35 is a needle, and 41 is a lower shaft.

Claims (1)

[Scope of utility model registration request] The rotation of the upper shaft causes the needle bar to move up and down, the rotation of the lower shaft causes the hook to rotate, the upper shaft is always rotated at 1/2 the rotation of the lower shaft, and the end of the needle bar A stitch is formed by intersecting each other due to the relative movement of the needle attached to the hook and the striped part of the shuttle, and the rotational phase of the upper shaft is adjustable with respect to the lower shaft. In a sewing machine in which a cross phase with a light section is adjusted, the sewing machine meshes with a drive gear rotatably supported by the upper shaft and rotated via a timing belt by a drive sprocket fixed to the lower shaft. an arm shaft that rotatably supports an intermediate gear and is fixed to the upper shaft; and an arm shaft that is fixed to the shaft of a step motor connected to the needle bar support via an amplitude iron for controlling the amplitude of the needle bar. It is characterized by comprising a control gear, and an adjustment gear that meshes with the control gear and is integrally formed with a gear rotatably supported on the upper shaft and meshes with an intermediate gear supported on the arm shaft. Stitch width expansion device for sewing machines.