JPS608849Y2 - Pattern selection device for pattern sewing machine - Google Patents

Description

[Detailed description of the invention] This invention is a pattern sewing machine with a 2-step buttonhole sewing function that counts a predetermined number of bar tack stitches using a ratchet operation and automatically shifts to overlock stitching. This invention relates to an improvement in a selection device.

In a pattern sewing machine that is equipped with a pattern cam group consisting of a plurality of width adjustment cams and feed cams, and from which a sewing pattern can be selected,
A technique for performing two-step buttonhole sewing by operating two selection dials is already known.

Among these methods, a predetermined number of bar tack stitches are counted by a ratchet operation synchronously driven from the upper shaft of the sewing machine in response to buttonhole sewing selection operation using a dial, and the bar tack is counted in response to the end of the bar tack. In models that automatically move to overlock stitching and stop ratchet counting, the ratchet wheel is also rotated when selecting with the dial, so - number of buttonholes can be completed. Even if you want to return to the starting point of buttonhole sewing and repeat it, the dial will pass through other pattern selection positions, and after rotating the entire circumference, the desired buttonhole sewing will begin. I had to set it up.

This is due to the one-way operation of the ratchet mechanism, and when there are many other types of pattern stitching, it is a slightly troublesome operability problem.

The present invention has solved this problem, and to describe it specifically, for example, the
28956, by means of a two-step buttonhole via a ratchet mechanism, i.e. a ratchet wheel that rotates in increments for a predetermined number of bartack stitches, and upon completion of the rotation corresponding to the predetermined number of bartack stitches. A buttonhole control cam that rotates together with the ratchet wheel and stops the ratchet from advancing during oversewing is installed coaxially with the buttonhole control cam, and a latch that is driven synchronously from the upper shaft of the sewing machine is slid onto the circumference of both. In an automatic buttonhole switching device that has a so-called double ratchet stepping mechanism, a latch release means is provided coaxially with the ratchet wheel and buttonhole control cam, and dial operation is performed. When the shaft is rotated in a direction opposite to the direction of ratchet operation, the action of the latch release means causes the latch to slide around its circumference while the ratchet is suspended in stepwise motion, thereby for repeating the buttonhole. It is characterized by easy dial operation.

Referring to the figures below, this embodiment is an example in which the pattern selection cam shaft and the buttonhole ratchet wheel shaft are separate shafts, and this is a deceleration shaft to reduce the operating force of the selection dial. A check configuration using a buttonhole is arranged on the relay shaft, and even if both are coaxial, the same effect can be obtained.

In FIG. 1, a frame 1 is attached to a sewing machine frame (not shown) by four fasteners 3 so as to cover an upper shaft 2 of the sewing machine.

The frame 1 has four parallel shafts arranged perpendicular to the upper shaft 2.

First, the pattern cam shaft 4 is fixed to the frame 1, and a worm gear 5, a width pattern cam group 6 and a feed cam group 7 are integrally connected and fixed on the shaft, and are fixed to the shaft. A worm gear 5 is engaged with and pivotally supported by a worm 8 supported on a shaft 2.

The small pattern cam group 6 has three width extension cams 5a, 6b, and 6c for buttonholes, and the feed cam group 7 includes cams 7a and 7b for zero feed and reverse feed during buttonholes. It is something that exists.

Corresponding to each of the width pattern cam group 6 and the feed cam group 7, a width contact group 9 and a feed contact group 10 are supported on contact shafts 11 fixed to the frame 1, respectively.

As shown in FIGS. 2 and 3, these two contact groups 9 and 10 are each supported by a contact shaft 11 passing through long holes 9a and 10a that are long in the left and right direction. Child 9
, 10 has its lower end connected to the corresponding rain pattern cam feed cam 6,
Even if the contact shaft 11 slides into contact with the guide pin 7 and its upper end is supported by contact with the guide pin, the contact shaft 11 does not function as a pivot shaft by itself, and thus does not play the role of a cam follower.

The contact shaft 11 also swingably supports an extension guide 12 and a feed guide 13, which are formed by bending a plate material into a U-shape. The extension drive arm 14 is pivotally supported.

An extension guide pin 15 is provided at the upper end of the extension guide 12 so as to come into contact with each upper end of the extension contact group 9.

As shown in FIGS. 1 and 2, the extension guide 12 is provided with a push screw 18 whose protrusion length to one side is adjusted by an adjustment nut 17, and the protruding end of the push screw 18 is driven to extend the width. It is in contact with the upper end of the arm 14, and when any of the extension contacts 9 swings counterclockwise, the entire extension guide 12 swings in the same direction via the extension guide pin 15. In this way, the extension drive arm 14 is similarly given a counterclockwise swing.

The lower end of the width drive arm 14 is connected to the width adjustment 1 as usual.
It is connected to a link 20 via a link 9, and the tip thereof is connected to a needle bar arm (not shown).

Further, the width adjuster 19 is swingably supported by a shaft 21 on a rib on the side of the sewing machine frame (not shown).

As seen in FIGS. 1 and 3, one side of the feed guide 13 projects an arm portion 13a, to which a feed link 23 is connected via a pivot pin 22.

The lower end of the feed link 23 is linked to the feed arm 25 via another pivot pin 24, and the swing end of the feed arm 25, which is swingably supported on the frame 1 by a pivot 26, is connected to the feed arm 25 via an automatic feed rerod 27. The extension contact 9 and the feed contact 10 are connected to a feed mechanism (not shown), and a selected one of them acts as a cam follower. A group of width selection cams 28 and a group of feed selection cams 29,
Both are fixedly provided on the selection dial shaft 30.

The selection dial shaft 30 projects from the front of the frame 1, and has a dial indicator 31 integrally supported at its front end.
Further, a knob 32 is loosely fitted and supported at its base.

A ratchet drive arm 33 is pivotally supported in the middle of the selection dial shaft 30, and a drive arm removal cam 34 is mounted on one side of the width selection cam 28, integrated with this group of cams. They are coaxially supported, and an indexing ring 35 is fixed to the end of the shaft.

On one side of the feed selection cam 29, a gear 37 is also coaxially attached.
is formed.

The indexing ring 35 has a stopper ball 36 supported on the frame l side via a conventional pressure means pressed onto its circumference, and the engagement of the stopper ball 36 with the unevenness on the circumference causes a so-called click. This provides a motion positioning action to the selection dial shaft 30.

As shown in FIGS. 2 and 3, the ratchet drive arm 33 is pivotally supported on the selection dial shaft 30 at the middle of the inverted-shaped monopod, and is biased counterclockwise by a spring 38, so that the ratchet drive arm 33 is always The leg end is brought into sliding contact with the slope side of a ratchet drive cam 39 fixed to the upper shaft 2.

When the sliding contact is maintained as shown in FIG. 3, the rotation of the upper shaft 2 causes the ratchet drive arm 33 to swing in accordance with the advance and retreat of the sliding contact portion with the ratchet drive cam 39.

The other end of the ratchet drive arm 33 crosses over the right-adjacent ratchet shaft 40 and rotatably supports - latches 41 at its tip with a pin 42.

The latch 41 is biased clockwise by a spring 43 wound around a pin 42.

A reduction gear 44 is supported on one end of the ratchet shaft 40 and meshes with teeth provided on the circumference of the handle 32a of the knob 32.

Therefore, when the knob 32 is rotated, the ratchet shaft 40 is rotated in the opposite direction to the operating direction of the knob 32 at a reduction ratio of -2 in this embodiment.

This rotation is caused by a latch release cam 45 fixed on the same axis.
A gear 4 loosely fitted coaxially through a coupling means to be described later.
6, and rotates the gear 37 on the selection dial shaft 30 side, which is meshed with the gear 46 in a one-to-one ratio.

That is, when the knob 32 is rotated, the selection dial shaft 30 is also rotated in the same direction to form a rotation angle of -1/2.

The rotation of the selection dial shaft 30 is controlled by the dial indicator 31.
The display surface as shown in FIG.

A buttonhole control cam 47 is mounted on the ratchet shaft 40, sandwiched between the latch release cam 45 and the gear 46, and integrated with the gear 46, and further sandwiched between the buttonhole control cam 47 and the gear 46. A ring-shaped ratchet wheel 48 is coaxially supported so as to be freely rotatable.

The tips of the teeth of the latch 41 face the periphery of the latch release cam 45, the buttonhole control cam 47, and the ratchet wheel 48, and slide into contact with the outer periphery of the maximum diameter at each moment among the three. It is something that contributes to the operation of relationships.

The relationship between the teeth of the ratchet wheel 48 and the launch 41 is such that the clockwise direction on the ratchet shaft 40 in FIGS. 2 and 3 is the forward direction of the ratchet.

A check spring 49 is engaged on the circumference of the ratchet wheel 48.

However, since the ratchet wheel 48 is supported in free rotation as described above, the ratchet wheel 48 alone only rotates idly and does not rotate the ratchet shaft 40 step by step.

The rotation of the ratchet shaft 40 due to the rocking of the latch 41 occurs when the latch 41 acts on the buttonhole control cam 47.

That is, the teeth of the ratchet wheel 48 are provided with teeth with deep valleys every predetermined number of teeth, and when the tip of the tooth of the latch 41 engages with the teeth of the deep valleys, it engages with the circumferential locking shaped portion of the buttonhole control cam 47. At this time, the ratchet shaft 40 is rotated by one pitch, and after the rotation of the -pitch is completed, the latch 41 is simply rotated along the cam peripheral shape of the buttonhole control cam 47. The latch 41 remains idle until it simply slides and the ratchet wheel 48 is no longer advanced, and the buttonhole control cam 47 is then rotated by an external operation to bring the latch 41 into contact with the ratchet wheel 48. becomes.

Similar ratchet wheel 48 and buttonhole control cam 4
7, the mechanism that counts the movement of the latch 41 a predetermined number of times and then advances by one pitch is based on the above-mentioned Japanese Patent Publication No. 39
This is based on the technology disclosed in No.-28956 and the like.

To explain using the example illustrated in FIG.
a, and the latch 41 is now at the A position because the height of the top tooth 47a of the buttonhole control area shape carved on the circumference of the buttonhole control cam 47 is small. The stepwise drive to be applied in position rotates only the ratchet wheel 48.

And in the operation of the 6th step, one of the teeth of the deep valley 4
8a-1 reaches position A, and latch 41 falls into its valley, thereby engaging tooth 47b and rotating both one step.

As a result, the switching feed dog 47 of the buttonhole control cam 47
The latch 41 moved to b has a larger angle set on the cam slope than that of the ratchet wheel 48, which prevents the tips of the teeth of the latch 41 from engaging with the teeth of the ratchet wheel 48. It simply slides along the peak 47c of the slope.

That is, during this one-step ratchet operation of the buttonhole control cam 47, after bar tacking and oversewing, the buttonhole control cam 47 is rotated to engage the teeth at position B with the latch 41. By applying this to the sewing machine, similar sewing on the return trip can be controlled.

Next, the coupling relationship between the latch release cam 45 and the gear 46 described above will be explained.

As shown in FIGS. 5 to 7, the latch release cam 45 is provided with a window 45a on its plate surface, and the buttonhole control cam 47 is provided with a pin 50 that fits into the window 45a.

There is some play in this fitting, and the spring 52 is inserted between the spring post pin 51 and the pin 50 provided on the side of the latch release cam 45.
is stretched to maintain the shape shown in Figure 6 at all times.

As a result, when the ratchet shaft 40 is rotated in the α forward direction, the buttonhole control cam 47 is also immediately rotated by the latch release cam 45 fixed to the shaft via the pin 50, and the buttonhole control cam 47 is also rotated by the gear 46 integrated therewith. The rotation is transmitted to the selection dial shaft 30, and the width selection cam 28, the feed selection cam 29, etc. are rotated in a negative direction.

When buttonhole stitching is selected by this rotation of the ratchet shaft 40 by operating the knob 32 guided by the display on the dial indicator 31, the dial indicator 31a
When the buttonhole control cam 47 is aligned with the indicator 31b, the A position of the buttonhole control cam 47 is brought to the position relative to the latch 41, and when the buttonhole control cam 47 is aligned with the indicator 31b, the B position is brought under the tooth tip of the latch 41. Cam 28 and feed selection cam 29
and engages the corresponding width contact 9 and feed contact 10 with the cam 6a corresponding to bar tacking in the rain pattern cam group 6 and the cam 7a corresponding to zero feed in the feed cam group 7, respectively. It works as expected.

As for the selection operation using this knob 32, as mentioned above, the counterclockwise direction is the α forward direction of the ratchet shaft 40, but since the latch release cam 45 is provided, it can also be rotated in the opposite direction. Can be done.

As shown in FIG. 5, the latch release cam 45 has a cam area as shown corresponding to the buttonhole control area of the buttonhole control cam 47, that is, a pin 50
is in the rest position within the window 45a under the action of the spring 52 (Fig. 6).
At such a relative phase, slopes 45b are formed that ascend from the valleys of the control cam side switching feed tooth 47b and the backward switching feed tooth 47d toward the α forward direction side.

Furthermore, a slope 45C that similarly rises further from position A and position B on the control cam side is provided.

Therefore, when the ratchet shaft 40 is rotated in the direction opposite to α,
Initially, the latch 41 is engaged with the valley of the switching feed tooth 47b or 47d of the buttonhole control cam 47, and the buttonhole control cam 47 does not rotate, but the latch release cam 4
While only the latch release cam 5 rotates by the amount of play of the pin 50 in the window 45a against the spring 52, the latch release cam 4 rotates as shown in FIG.
The slope 45b of No. 5 pushes the tooth tip of the latch 41 to the outside of the periphery,
When the tooth tip of the latch 41 deviates from the valley, the buttonhole control cam 47 rotates one step in the opposite direction.

Then, by the subsequent rotation of the latch release cam 45 in the opposite direction, the cam slope 45c similarly pushes out the tip of the latch 41 tooth from the valley at the A or B position of the control cam, and in the opposite direction to α in two ways. The ratchet shaft 40 is moved in the opposite direction by the action of the latch release cam 45 that acts during the idle stroke of both cams.
In other words, the knob 32 can be rotated in both directions.

Next, the ratchet drive arm 33 and the drive arm outer cam 3 are explained below.
I will explain the relationship with 4.

Dial indicator 31 without buttonhole sewing selected
When aligned with other indicators such as the sewing pattern 31c above, this is to stop unnecessary swinging of the latch 41, and the shape of the drive arm release cam 34 can be better understood from FIGS. 8 and 9. As shown in FIG. 3, the buttonhole control cam 47 has a small diameter portion 34a on the outer periphery at an angle corresponding to the buttonhole control area protruded in front of the buttonhole control cam 47. Cam facing end 33a of arm 33
A relay lever 53 for controlling engagement and disengagement of the ratchet drive cam 39 is rotatably supported on the ratchet shaft 40.

The relay lever 53 has a crank-like shape, and is biased clockwise by a spring 54 mounted between its supporting leg and the frame 1, and the other supporting leg is further divided into two, and its long wave end 53a is biased clockwise. The implanted pin 55 is always attached to the drive arm removal cam 34.
It is slid onto the circumference of the

Further, the pin 56 implanted in the short branch end 53b is inserted into the recess 33c formed in the crotch of the ratchet drive arm 33 when the long wave side pin 55 is in sliding contact with the cam small diameter portion 34a (FIG. 8).
When the selection dial shaft 30 is rotated due to selecting a method other than buttonhole sewing, the long wave side pin 55 is out of the range of the cam small diameter portion 34a as shown in FIG. As a result, the relay lever 53 is rotated counterclockwise against the spring 54, and the short-wave side pin 56 moves inside the recess 33c and touches the little finger section 3
3b and press it to rotate the ratchet drive arm 33 clockwise against the spring 38, ie, to pull its cam-facing end 33a out of engagement with the ratchet drive cam 39, as shown.

As a result, in the selected state other than buttonhole sewing, the ratchet drive arm 33 stops swinging in the state shown in FIG. We only interact quietly on top.

With the above configuration, the operation of the main selection device will be described once again. In selecting a sewing pattern by rotating the knob 32,
When rotating the knob 32 at an index point other than buttonhole sewing using the dial indicator 31, the selection dial axis 3
0 rotation, due to the action of the drive arm removal cam 34,
As described above, the ratchet drive arm 33 is placed in the rest state as shown in FIG. 9 via the relay lever 53.

Then, depending on the rotational position of the selection dial shaft 30 at this time, the width adjustment contact 9 and the feed contact 10 corresponding to each selected width selection cam 28 and feed selection cam 29 are set in the usual manner. The sewing machine is given the role of acting as a cam follower, and controls the width setting and feeding according to each corresponding cam in the width pattern cam group 6 and the feed cam group 7, respectively.

When buttonhole sewing is selected, use the ratchet drive arm 3.
3 is in a swinging state according to the ratchet drive cam 39 as shown in FIG. 8, and is driven in synchronization with the rotation of the upper shaft 2.

Only the ratchet wheel 48 makes a stepwise motion for five stitches from the start of buttonhole sewing, during which the ratchet shaft 40 does not rotate, and the sewing machine moves according to the zero feed cam 7a in the feed cam group 7. In the state of zero feed, zigzag starting line sewing is performed according to the bar tacking control cam 6a in the starting cam group 6.

When the latch 41 is activated at the sixth stitch from the start of bar tacking, the buttonhole control cam 47 rotates one step as described above, and the stepwise movement of the ratchet wheel 48 is stopped, and the gear 46 and the gear 36 are rotated. Through the engagement, the selection dial shaft 30 is rotated by one step, thereby switching the selection status of the width selection cam 28 and the feed selection cam 29 from one equivalent to bar tacking to one equivalent to overlocking. , the zigzag start and feed of the sewing machine will also follow this.

Then, when the desired length of overlock stitching is completed, by operating the knob 32 and setting the starting position for the return trip or repetition, it is possible to perform a similar automatic switching operation from bar tacking to overlock stitching. .

During this operation of pattern selection using the knob 32, including buttonhole sewing, the tooth tip of the latch 41 is connected to the buttonhole control cam 4.
When the cam part of the buttonhole control area 7 passes through, the latch 41 is not locked by the buttonhole control cam 47 when rotating in the forward direction shown as α in FIGS. The latch 41 for the tooth of the buttonhole control cam 47 allows the rotation freely, and for rotation in the opposite direction to α.
The reverse rotation is obtained by unlatching the lock and pushing it out by the action of the cam 45.

At this time, at each starting point of the action of the latch release cam 45, the latch 41 is pushed out through a so-called butt crushing process during which the control cam side pin 50 moves within the release cam side window 45a by the amount of play. This is as mentioned above.

At the end of each step rotated in any direction in this way, the selection dial shaft 30 tends to be held at each step position by the cooperation of the indexing wheel 35 and the stopper ball 36, i.e., The rotation operation by the knob 32 is switched one after another by a smooth and stable operation of a so-called click motion for each step.

As explained above, the present invention is to count the predetermined number of bar tacking stitches by advancing the ratchet wheel and automatically proceed to overlock stitches.
- Conventionally, in the step buttonhole control mechanism, the knob operation direction of the selection dial was limited to one rotation only due to the original one-way function of the ratchet mechanism, but according to the present invention, the ratchet wheel and In addition to the conventional configuration with the buttonhole control cam, a latch release cam is attached, and the ratchet shaft can be rotated in the opposite direction by a simple method of releasing the latch that acts during the reverse direction of the buckling process. Therefore, since the selection dial can be rotated in any direction, operations such as repeated buttonhole sewing become easier.

[Brief explanation of drawings]

The figures show one embodiment, and FIG. 1 is a plan view thereof, and FIGS. 2 and 3 are explanatory diagrams of each partial mechanism in the pattern selection device.
The figure is a front view showing the pattern cam and the width adjustment mechanism, and FIG. 3 is a front view showing the feeding mechanism. FIG. 4 is a front view of the selection dial section, FIG.
7 and 7 are explanatory diagrams of each operating state, and FIGS. 8 and 9 are diagrams explanatory of each operating state of other essential parts. 2: Sewing machine upper shaft, 28 double thread selection cam, 29: Feed selection cam, 40: Ratchet shaft, 41: Latch, 45: Latch release cam, 47: Buttonhole control cam, 48: Ratchet wheel, 45a, 50: Window and pin of locking means with play in the opposite direction of the ratchet between the latch release cam and the buttonhole control cam, 45bt 45c: Latch release slope on the circumference of the latch release cam.

Claims (1)

[Scope of utility model registration request] A predetermined number of bar tacking stitches is counted by the stepwise movement of a ratchet wheel that is driven by a latch that is swing-driven from the upper shaft of the sewing machine, and upon completion of the step of the predetermined number of stitches, a button attached to the ratchet wheel is pressed. The hall control cams are rotated together,
A pattern stitch sewing machine having a 2-step buttonhole mechanism in which a latch release cam is fixed on the same axis, the width adjustment and feed selection cams are switched to those for overlocking, and the advancing operation of the ratchet wheel is stopped. In the pattern selection device, the ratchet wheel and the buttonhole control cam are supported by a ratchet shaft with a loose fit in the combination of the ratchet wheel, the buttonhole control cam, and the latch release cam, and the buttonhole control cam has the following features: The ratchet wheel is locked with play in the direction of rotation in the opposite direction of the ratchet wheel, and by rotation of the ratchet wheel in the direction of rotation in the direction of rotation with play in the direction of rotation in the opposite direction, the tip of the tooth of the latch is placed on the cam circumference of the buttonhole control cam. The latch release cam, which has an outwardly pushing slope, is supported on the ratchet shaft, and has a selection dial that is supported coaxially with the ratchet shaft, or is engaged with a spur gear in parallel to the ratchet shaft and the selection dial. A pattern selection device characterized in that the can be rotated in any direction.