JPS5922550B2 - Tie-stitch device in electric sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the rotational speed of the motor is selected and set in advance by a speed setting means connected to a motor drive circuit and operable from outside the sewing machine frame, and the rotation speed of the motor is selected and set in advance by operating a manual operation unit. A so-called electric sewing machine with a built-in controller is configured such that the sewing machine is operated at a preset motor rotational speed after the motor is started, and the operation is stopped by operating the manual operation unit. In particular, the manual operating body has a first position for stopping operation of the sewing machine, a second position for operating the sewing machine, and a third position for performing another tacking stitch. When the manual operation member is moved to the third position, the motor is driven at a low speed, regardless of the rotational speed set by the speed setting means. The present invention relates to a tacking device that is capable of performing tacking at low speed.

A conventional electric sewing machine equipped with a tacking device is, for example,
No. 9-96848, etc., but in this sewing machine, the rotational speed of the motor is controlled by a controller that can be operated by pressing. Since the sewing machine is then operated at high speed, undesirable phenomena may occur, such as not being able to perform tacking at a required location, or tacking for an unnecessary length.

Further, among the so-called controller-built-in sewing machines according to the present invention, no one equipped with a tacking device has yet been provided.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electric sewing machine in which operation of the sewing machine at a preset speed and stopping of the operation can be controlled by operating a manual operation member. The object of the present invention is to provide a device that can perform locking stitches safely, accurately, and extremely easily at low speeds by operating the manual operation body, and furthermore, to provide a device that can be applied to different types of locking stitches in such electric sewing machines. The object of the present invention is to provide a low-speed tacking device.

The details of the present invention will be explained below with reference to the drawings showing one embodiment.

In the figure, 1 is a main shaft of the sewing machine supported on a sewing machine frame 2, 3 is a handwheel fixed to the end of the main shaft, 4 is an electric motor for driving the main shaft 1, and a motor pulley 5
The main shaft 1 is driven via a belt 7 that is hung between the main shaft 1 and a drive pulley 6 fixed to the main shaft 1.

Reference numerals 8, 9, and 10 are speed setting push buttons for pre-selecting and setting the rotational speed of the motor 4, and a release push button 1
1 and are arranged in front of the column of the sewing machine.

12 is a decorative plate fixed to the front surface of the pillar portion; 13 is a first manual operation knob for amplitude adjustment fixed to a shaft 14 rotatably supported by the decorative plate 12; 15 is the knob 13;
An adjustment plate 16 is fixedly attached to the shaft 14 so as to rotate together with the shaft 14, and 16 is an operating arm loosely fitted to the shaft 14, and is operatively connected to a known needle bar connecting rod (not shown) by a connecting ring 17. The needle bar connecting rod is moved by the rotation of the operating arm 16 about the shaft 14, and the rollers supported by the needle bar connecting rod and the swinging of a known swing link (not shown) are connected to each other. By changing the distance from the dynamic fulcrum, the amount of swinging momentum imparted to the needle bar can be changed.

Further, an engaging pin 18 is implanted in the operating arm 16, and a forked portion 16a is formed, and the retaining pin 18 is formed with a forked portion 16a.
is opposed to the protrusion 15a formed on the adjustment plate 15.

Reference numeral 19 denotes a link lever rotatably supported by a shaft 20 fixed to the decorative plate 12, and a pin 21 implanted at one end of the link lever 19.
is fitted into the forked portion 16a of the operating arm 16, and the linking lever 19 is biased counterclockwise in FIG. 2 by the action of a tension spring 22 stretched between it and the decorative plate. , thereby imparting a rotational force to the operating arm 16 in the clockwise direction in the figure.

Therefore, the engagement pin 18 comes into contact with the protrusion 15a of the adjustment plate 15, and urges the adjustment plate 15 together with the shaft 14 and the first manual operation knob 13 in the clockwise direction in the figure. Since the manual operation knob 13 is configured to be held at any rotational position against the biasing force by a locking means similar to a second manual operation knob described later, the operating arm 16 also The engaging pin 18 contacts the protrusion 15a of the adjustment plate 15, and subsequent rotation is restricted.

Therefore, when the manual operation knob 13 is now rotated, the adjustment plate 15 and the operating arm 16 are rotated together, and as described above, the position of the roller relative to the pivot point of the pivot link is changed. , which can change the swing amplitude applied to the needle bar, and the swing link, rollers, chain link 17, operating arm 16, etc. constitute an amplitude adjuster.

Further, 23 is a shaft 24 rotatably supported by the decorative plate 12.
a second manually operated knob for adjusting the feed rate, fixed to 2;
5 is attached to the shaft 24 so as to rotate together with the knob 23.
A feed adjusting cam body 25 is fixed to the feed adjustment cam body 25, and a normal feed amount setting cam surface 25a is formed at the end of the cam body 25.

Reference numeral 26 denotes a leaf spring fixed to the back surface of the decorative plate 12 by a screw 27, and a locking pin 28 is fixed to the tip of the leaf spring, and the locking pin 28 passes through the decorative plate 12 and connects the second plate. It engages with a knurl carved on the back side of the manual operation knob 23 to hold the knob 23 in any rotational position.

Furthermore, 29 is a bracket fixed to the frame of the sewing machine;
0 is a feed control lever rotatably supported on the bracket by a step screw 31; 32 is a feed control arm rotatably supported by the step screw 31; the arm is fixed to the lever 30 by a screw 33; Rotates together with the lever.

At the tip of the feed control arm 32 is a retaining pin 34 that can be relatively engaged with the cam surface 25a of the feed adjustment cam body 25.
has been planted.

35 is a feed adjustment shaft that is rotatably supported by the sewing machine frame and the bracket 29, 36 is a known feed adjustment member fixed to one end of the shaft, and 37 is fixed to the other end of the shaft 35. 38 is a rod that connects the connecting arm with the feed control lever 30; 39 is the feed adjustment shaft 3;
A coiled spring wound around the shaft 35 applies a rotational force to the shaft 35 in the clockwise direction in FIG. It comes into contact with the cam surface 25a.

Therefore, when the second manual operation knob 23 is rotated, the feed adjustment shaft 35 is rotated by the feed adjustment cam body 25, the feed control arm 32, the feed control lever 30, the rod 38, and the connecting arm 37. The feed amount applied to the feed dog can be adjusted by changing the setting position of the feed adjustment body 36, and the feed adjustment body 36, the feed control lever 30, the feed control arm 32, and the feed adjustment cam The member 25 and the like constitute a feed adjuster.

Note that the operational connection between the feed adjustment body 36 and the feed dog is well known and will therefore be omitted.

A manual operation lever 40 is located above the jaw of the sewing machine and can be operated from the front side of the sewing machine, and is fixed to the front end of a shaft 410 rotatably supported on the sewing machine frame. A connecting arm 42 is fixed to the rear end side.

43 is a step screw 45 attached to a support plate 44 fixed to the sewing machine frame.
The operating arm is rotatably attached to the operating arm, and one of the arms is connected to the connecting arm 42 by a link 46, and the thin arm is formed with an operating projection 43a and a fitting hole 43b.

Reference numeral 47 denotes a switching arm rotatably attached to the support plate 44 by the step screw 45, and a shaft pin 48 having first to third shaft cylinder portions 48a to 48C is fixed to one arm. Due to the action of a tension spring 49 stretched between the narrow arm and the operating arm 43, the second cylindrical portion 48b contacts the upper edge of the fitting hole 43b of the operating arm 43, and is always in this state. The operating arm 43 and the switching arm 47 rotate integrally.

Reference numeral 50 denotes a switching lever rotatably attached to the sewing machine frame 2 by a step screw 51 at the intermediate portion, and a forked portion 50a formed at one end thereof is connected to the third shaft cylinder portion 48e of the shaft pin 48.
are fitted, and the switching lever 50 is biased clockwise in FIG. 2 by the action of a tension spring 52 stretched between the sewing machine frame and the sewing machine frame.

Therefore, the switching arm 47 and the operating arm 43 are given a rotational force in the counterclockwise direction in the figure, and the operating arm 43
However, one edge is a bent portion 44a formed on the support plate 44.
2 and 4, it cannot be rotated counterclockwise from the position shown in FIGS. 2 and 4.

53 is a locking arm attached to the support plate 44 by a mounting shaft 54 so as to be rotatable and tiltable about the axis; 55 is a locking arm attached to the support plate 44 between the locking arm 53 and the support plate 44; 54, as shown in FIG.
One end thereof is locked to the support plate 44, and the other end extends along the locking arm 53 and is locked to an inclined portion to be described later. While applying power, the locking arm 53 is urged in the direction of the arrow in FIG.

Therefore, as shown in FIG. 4, the lower end protrusion of the locking arm 53 contacts one side edge of the support plate 44 to restrict its subsequent rotation in the clockwise direction. As shown in the figure, the mounting shaft 540 is in contact with the head and is always held in a state parallel to the operating arm 43 and the switching arm 47, and in this state, one side edge of the locking arm 53 is attached to the shaft. It is arranged so that it can be relatively engaged with the first shaft cylinder portion 48a of the pin 48.

One side edge of the locking arm 53 is provided with the shaft pin 4 when the switching arm 47 is rotated clockwise from the state shown in FIG.
The 10th axis cylinder portion 48a of No. 8 is engaged with the slanted edge 56 for rotating the locking arm 53 counterclockwise against the action of the coil spring 55, and has climbed over the slanted edge. The shaft pin 4
8 is a guide edge 57 that is secured when the switching arm 47 is rotated clockwise, and the guide edge 57 is engaged with the first cylindrical portion 48a (see FIG. 9). A locking edge 58 is formed to restrict further rotation of the switching arm 47.

59 is an engagement groove whose tip is located between the inclined edge 57 and the guide edge 58, and when the switching arm 47 is rotated counterclockwise from the state shown in FIG. The first shaft cylindrical portion 48a abuts to prevent the switching arm 47 from returning to the position shown in FIG.
is the coiled spring 5 from the position shown in FIG. 9 to the position shown in FIG.
It is allowed to rotate due to the action of 5.

The first shaft cylinder portion 48 is attached to the inner edge of the engagement groove 59.
When a is engaged, further rotation of the locking arm 53 is prevented and the locking arm 53 is held in the state shown in FIG. 8.

60 is a guide groove following the engagement groove 59 and allows the switching arm 47 to be rotated from the position shown in FIG. 8 to the position shown in FIG. The engagement of the first 0-axis cylinder portion 48a prevents the switching arm 470 from rotating clockwise thereafter.

Reference numeral 61 denotes an inclined portion that continues to and is located above the right side edge of the guide groove 60, and as shown in FIG. 6, its tip is inclined in a direction away from the switching arm 47 and the operating arm 43.

Therefore, from the state in which the locking arm 53 engages with the shaft pin 48 at the two-dot chain line position shown in FIG.
7 is returned to the counterclockwise direction, the tip of the shaft pin 48 presses the inclined portion, and the locking arm 53 is rotated by the winding spring 55.
The switching arm 47 is tilted in a direction opposite to the direction of the arrow shown in FIG. 6 against the action of the switch arm 47, thereby allowing the switching arm 47 to return to the position shown in FIG.

Note that 62 is a bent portion formed on the other side edge of the locking arm 53, and as is clear from FIG. 6, the operating arm 43
It stands upright in the direction toward , and has an inclined surface formed at its tip, and is arranged so as to be able to operatively engage with the operating protrusion 43a of the operating arm 43, as will be described later.

With such a configuration, the manual operation lever 4
0 are the three positions P1.0 shown in FIG. P2. It can be selectively moved to P3.

Further, referring to FIGS. 2 and 3, reference numeral 63 denotes an actuating lever rotatably attached to the bracket 29 by a pivot 64, and the tip 63a of one arm thereof is attached to the linking lever 19.
It faces the other end 19a from above, and the tip of the thin arm is connected to the other end of the switching lever 50 by a rod 65.

Further, an eccentric roller 66 is fixed to the operating lever 63 so as to be adjustable with a screw 67, and the operating lever 63 is fixed to the third
When rotated counterclockwise in the figure, the eccentric roller 6
The peripheral edge of 6 engages with the lower edge of the feed control lever 30,
The feed control lever 30 is rotated in the same direction.

Reference numeral 68 denotes a rotating lever that is rotatably fitted loosely on the feed adjustment shaft 35 and is connected to the operating lever 63 by a rod 69.

70 is a mounting plate fixed to the sewing machine frame, 71 is a pivot 72
The switch actuating cam body is rotatably mounted on the mounting plate 70 by the rod 73, and the rotary lever 6 is rotated by the rod 73.
It is connected to 8.

Reference numerals 74 to 76 denote three switches, which will be described later, which are fixed in parallel to the mounting plate 70, each actuator of which is provided so as to be able to engage with the lower side of the switch actuating cam body 71. It is configured so that it can be operated sequentially by a cam portion 71a formed in the portion.

Next, an embodiment of the electric circuit will be described with reference to FIG.

P and N are AC busbars derived from power supply terminals 77 and 78 connected to an AC power supply, and between these busbars P and N, the electric motor 4 such as a commutator motor for driving the main shaft of the sewing machine is connected.
and a thyristor 79 for controlling power supply to the motor are connected in series.

A protective varistor 80 is connected in parallel to this thyristor, and a parallel circuit consisting of a resistor 81 and a capacitor 82 is connected between the gate and cathode of the thyristor 79 as means for preventing erroneous ignition.

Furthermore, a signal level setting circuit for setting the signal level of the trigger signal to the thyristor 79 is connected between the buses P and N via a second thyristor 83, and this setting circuit is connected to a plurality of resistors 84. A series circuit consisting of the resistors 85 to 88 and the diode 89, and one of the resistors 85 to 88 connected to the switch 76, 75 and the diode 9
speed setting selection switches 90 to 92 for selectively connecting to the gate of the thyristor 79 via the resistor 9 connected in parallel to the series circuit of the resistors 86 to 88;
4 and a series circuit consisting of a capacitor 95.

A parallel circuit consisting of a resistor 96 and a capacitor 97 is connected between the gate and cathode of the second thyristor 83.

The selection switches 90 to 92 are respectively closed in conjunction with the suppression operation of the speed setting pushbuttons 8 to 10 (see FIG. 1).

Further, the switch 76 is open when the manual operation lever 40 is located at the position P1 shown in FIG.
．． It is closed when it is located at or between P3.

Further, the switch 75 is switched to the contact side when the lever 40 is moved to position P3, and is normally switched to the contact a side.
It is connected to the.

Further, a resistor 98 and a diode 99 are connected between the bus lines P and N.
, a switch 74 connected to the contact point, and a capacitor 100
are connected in series through the diode 89, and the other contact a is connected through a resistor 101 and a diode 102 to the gate of the second iris resistor 83.

Each terminal of one of three adjustable resistors 104 to 106 arranged in parallel is connected to the base of a transistor 1030 which is connected in parallel to the series circuit of the resistors 86 to 88 to form a bypass circuit. ,
The other terminals are respectively connected to interlocking switches 107 to 109 that open and close in conjunction with the selection switches 90 to 92, respectively, and these interlocking switches are connected to contact a of the switch 74 via a resistor 110. ing.

Further, a series circuit consisting of a resistor 111 and a capacitor 112 is connected in parallel to the series circuit of the switch 74 and the capacitor 100 when the switch is switched to the contact a side.

Note that 113 is a protective resistor connected between the base and emitter of the transistor 1030, and 114 is a resistor connected to the series circuit of the diode 99, switch 74, and capacitor 100.

Further, a series circuit of a capacitor 115, a resistor 116, and a diode 117 is connected between the connection point between the resistors 85 and 86 and the gate of the second Zyrister 83, and the connection point between the resistors 84 and 85 is connected. and the capacitor 115
A diode 118 of the illustrated polarity is connected between the connection point of the resistor 116 and the resistor 116 .

Note that 119 is a noise prevention capacitor connected between the bus lines P and N, and 120 is a lamp that is also connected between the bus lines P and N.

The operating mode of the embodiment device configured as described above will be explained.

2 to 7 show the state when the manual operation lever 40 is located at the sewing machine stop position P1 and the operation of the sewing machine is stopped, and the release push button 11 shown in FIG.
is suppressed and the selection switches 90 to 9 shown in FIG.
2 and the interlocking switches 104 to 106 are all open.

Further, the positions of the adjustment plate 15, actuating arm 16, connecting rod 17, etc. shown by solid lines in FIG. The position of the feed adjustment cam body 25, the feed control arm 32, the feed control lever 30, etc. shown in FIG. However, as described above, these can be arbitrarily changed and set by operating the first and second manual operation knobs 13 and 23.

When the power switch 121 is closed in FIG. 7, the lamp 120 disposed inside the sewing machine head lights up.
The user of the sewing machine senses that the power has been turned on.

Then, in order to set the operating speed of the sewing machine to high speed, medium speed, or low speed, push button 8 for speed setting shown in FIG.
When one of the buttons 9 and 100, for example, the push button 8 for high speed setting, is pressed, the push button 8 is held in the pressed state by appropriate means, and the selection switch 90 for speed setting is closed. , the interlock switch 107 is closed.

Therefore, in order to operate the sewing machine, the manual operation lever 40 is moved to the second position.
When the operating arm 43 is rotated in the clockwise direction from position P1 in the figure, the upper edge of the fitting hole 43b presses the 20th shaft cylinder portion 48b of the shaft pin 48, and the switching is performed. Arm 47 is also rotated in the same direction.

As a result, the switching lever 50 is rotated counterclockwise in FIG. 2 against the action of the tension spring 52, and the actuating lever 63 is rotated via the rod 65. Switch actuating cam body 71 via rod 73
rotates.

When the manual operating lever 40 reaches the rotational position P2, the switch actuating cam body 71 causes the switch 7 to
The actuators 4 and 76 are suppressed, and the switch 74 is switched to the contact a side in FIG.
6 is closed.

The fact that the manual operation lever 40 has reached the rotational position P2 occurs when the first shaft cylindrical portion 48a of the shaft pin 48 crosses over the inclined edge 56 of the locking arm 53 and comes into contact with the guide edge 57. If the operator senses the sudden change in rotational resistance of the manual operation lever 400 and the contact sound, and releases the lever 40 at that point, the first shaft cylinder portion 48a will open as shown in FIG. The manual operation lever 40 is held in a state engaged with the upper edge of the engagement groove 59, that is, in a downward rotation position P2 in FIG. 2 against the action of the tension spring 52.

In this state, the eccentric roller 66 of the operating lever 63 has no relation to the feed control lever 30, and the tip 63a of the operating lever 63 does not engage with the end 19a of the link lever 19.

By switching the switch 74 to the contact a side, the electric charge of the capacitor 100 that has been charged up to that point is input to the gate of the second thyristor 83 via the resistor 101 and the diode 102, and this thyristor conduction,
Capacitor 115 is charged via resistor 84 and diode 118.

On the other hand, the charge of the capacitor 100 is input to the base of the transistor 103 via the resistor 110, the interlocking switch 107, and the resistor 104, and this transistor is turned on.

Therefore, due to the conduction of the second thyristor 83, the bus line P
At first, the current flowing into the signal level setting circuit hardly passes through the series circuit of resistors 86 to 88, detours to a bypass circuit made up mostly of transistor 103, passes through diode 89, and flows to bus line N.

As the discharge of the capacitor 100 progresses, the input to the base of the transistor 1030 decreases, the current flowing through the bypass circuit gradually decreases, and the current flowing through the series circuit of the resistors 86 to 88 gradually increases. When the discharge of the capacitor 100 is almost completed, the transistor 103 is turned off and the bypass circuit is cut off.

Therefore, the trigger signal to the first thyristor 79 from the signal level setting circuit is extremely small at ℃ immediately after the switch 74 is switched to the contact a side and the switch 76 is closed. Although it does not become conductive, the signal level gradually rises to make the thyristor 79 conductive, and power is supplied to the electric motor 4 to start the motor.

As the conduction angle of the thyristor 79 widens, the rotation speed of the motor 4 increases, and when the transistor 103 turns off, a trigger signal of a level set by the selection switch 90, which is selectively closed in advance, is applied to the thyristor 79. input, and the motor 4 reaches a predetermined rotational speed.

By the way, since the capacitor 115 is charged when the second thyristor 83 conducts, the capacitor 10 described above is charged.
When the discharge of 0 is almost completed, the charge of the capacitor 115 is input to the gate of the second thyristor 83 via the resistor 116 and the diode 117 instead of the capacitor, and this thyristor is maintained in a conductive state.

Once the thyristor 83 is conductive, the operation of the sewing machine is stopped, that is, the switch 76 is opened and closed, or the switch 74 is turned off.
．． The capacitor 115 is maintained in a conductive state regardless of the switching operation of the capacitor 115, and during this period the capacitor 115 is repeatedly charged and discharged.

Therefore, after the transistor 103 is turned off, the motor is driven to constant rotation at a rotation speed preset by the speed setting push button 8.

When the sewing machine is operated in this manner, the desired sewing work is performed with the amplitude and cloth feed amount set by the first and second manual operation knobs 13 and 23. When the push button 9 or 10 is pressed, the selection switch 90 and the interlocking switch 107 are opened, and the selection switch 91 or 92 is closed together with the interlocking switch 108 or 109, and the thyristor 79 has the above-mentioned effect. A signal level lower than that is input, and the motor 4 is driven at a corresponding rotational speed (medium speed or low speed).

At this time, since the capacitor 100 has been discharged, the transistor 103 remains off.

When the manual operation lever 40 is rotated back from the rotational position P2 to the original position P□, the switch 76 is opened and the trigger signal to the first thyristor 79 is cut off. The power supply is cut off and the sewing machine stops at the final position.

Further, the changeover switch 74 returns to the contact side, and the capacitor 100 is charged.

It is clear from the above description that the second thyristor 83 continues to be kept conductive.

The manual operation lever 40 is rotated back to the original position P1 in the following manner.

That is, when the manual operating lever 40 is rotated from the state shown in FIG. 8, the operating arm 43 is rotated counterclockwise in the figure independently of the switching arm 47, and the operating protrusion 43a is rotated into the locking arm. 5
(see FIG. 10), and moves the locking arm 53 backward (to the right in FIG. 6) against the action of the coil spring 55.

Therefore, the 10th shaft cylindrical portion 48a of the shaft pin 48, which had been locked in the engagement groove 59 of the locking arm 53, disengages from the engagement groove 59, and the tension spring 49 Due to this action, it passes over the front surface of the locking arm 53.

Therefore, when the manual operating lever 40 is rotated back to the original position P1, the operating arm 43 and the switching arm 47 return to the positions shown in FIGS. 2 and 4, and the switching lever 50, operating lever 63, The switch operating cam body 71 and the like also return to the positions shown in FIGS. 2 and 3, and the switch 76 is opened as described above.
It is intended to open up the

When sewing a new sewing location, the pushbuttons 8 to 1 are used to set the motor speed to a desired rotational speed.
0, close one of the selection switches 90 to 92, and rotate the manual operation lever 40 again to the P2 position, the switches 74 and 76 will operate in the same manner as described above, and the The level of the trigger signal to the first thyristor 79 gradually increases in accordance with the discharge of the capacitor 100, and
The rotation speed is gradually increased in the same manner as when a conventional controller is gradually depressed, and after reaching a preset speed, the rotation speed is constant at that speed.

Incidentally, in the present embodiment, the manual operation lever 40 is configured so that it can also be moved to the rotational position P3 shown in FIG. It operates.

That is, when starting sewing, the manual operation lever 40 is moved from the sewing machine stop position P1 to the sewing machine operating position P2 to the position P2.
3, the operating arm 43 and switching arm 47 move to the 9th position.
The first shaft cylinder portion 4 of the shaft pin 48 is moved to the state shown in the figure.
8a engages with the locking edge 58 of the locking arm 53, and the lever 4
It is held in that position while 0 is pressed from above.

By rotating the switch lever 50 to the position P3, the switching lever 50 moves to the second position.
The actuating lever 63 is rotated to the maximum in the counterclockwise direction in FIG. 3 via the aforementioned rod 65.

As a result, the eccentric roller 66 comes into contact with the lower edge of the feed control lever 30 and rotates the lever 30 in the same direction, and the feed adjustment shaft 35 is connected to the helical spring 39 via the rod 38 and the connecting arm 37.
It is rotated together with the feed adjustment member 36 against the action of the feed adjustment member 36.

As a result, the feed adjustment member 36 is changed to a state suitable for locking stitches, such as a state in which a minute forward feed amount or a minute backward feed amount can be applied to the feed dog.

At this time, since the engagement pin 34 of the feed control arm 32 moves in a direction away from the normal feed cam surface of the feed adjustment cam body 25, the setting operation of the second manual operation knob 23 is disabled.

Further, the rotational position of the feed adjustment member 360 is determined by the rotation position of the eccentric roller 6.
It can be adjusted by rotating 6.

On the other hand, as the operating lever 630 is rotated, its tip 63a presses the end 19a of the linking lever 19 from above, and the lever 19 is rotated to the position indicated by the two-dot chain line in FIG.

Therefore, the actuating arm 16 is rotated from the solid line position B to the two-dot chain line position A regardless of the adjustment plate 15, and the needle bar connecting rod is rotated through the connecting rod 17 regardless of the setting operation of the first manual operation knob 13. Align the roller with the swinging fulcrum of the swinging link, and change the swinging amplitude of the needle bar to zero.

Furthermore, as the operating lever 630 rotates, the switch operating cam body 71 is rotated as described above, and each switch 74,
75 and 76 operate as follows.

That is, the manual lever 40 is at the second rotational position P described above.
2, the switch 76 is closed and the switch 74 is temporarily switched to the contact a side, and the capacitor 100
is input to the gate of the second thyristor 83.

Therefore, when the thyristor 83 is not in a conductive state, the thyristor becomes conductive and the motor 4 attempts to start slowly.

However, when the manual operating lever 40 is moved to the 30th rotation position, the switch 74 returns to the contacting side and the switch 75 switches to the contacting side.

Therefore, even if the selection switch 90 for high-speed setting is closed, the motor 4 is driven at low speed in the same way as when the selection switch 92 for low-speed setting is closed.

At this time, when the switch 74 is switched to the contact a side, the electric charge of the capacitor 112, which is instantly charged by the discharge of the capacitor 100, is transferred to the transistor 1030 through the resistor 111 and the closed interlocking switch.
Since the input signal is input to the base, the transistor is turned on and the bypass circuit is activated, causing the so-called slow start phenomenon in which the rotation speed of the motor 4 gradually increases, as described above, and the rear leg motor is driven at a predetermined constant low speed. Rotationally driven.

Note that the capacitor 112 is connected to the second thyristor 8.
3 also has the effect of making the thyristor 83 conductive when the aforementioned switch 74 does not reach the conductive state when it is switched to the a side, but as described above, once the thyristor 83 is conductive, the power switch 121 Since it is maintained in a conductive state until it is opened, the above-mentioned effect occurs only at the beginning of use of the sewing machine.

As described above, the manual operation lever 40 is in the third position P.
3, the first manual operation knob 13
The oscillation amplitude of the needle bar is changed to zero regardless of the setting state of the second manual operation knob 23, and the fabric feed amount is changed to a feed amount suitable for tacking stitches (minor feed) regardless of the setting state of the second manual operation knob 23. In addition, the motor is changed so that it is driven at a low speed regardless of the speed selection setting state by the speed setting push buttons 8, 9, and 10, so that the fastening stitch can be easily performed at a low speed. obtain.

After performing the desired tacking stitches as described above, when the pressure on the manual operation lever 40 is released, the switching lever 50 is rotated by the action of the tension spring 52, and the switching arm 47 and the operating arm 4 are rotated.
The third and other parts move to the state shown in FIG. 8, and the first shaft portion 48a of the shaft pin 48 engages with the engagement groove 59 of the locking arm 53 and is held in that state.

At this time, the manual operating lever 40 is moved and held at the second position P2, and the operating lever 63 and the switch operating cam body 71 are also moved to the corresponding positions.

Therefore, the switch 75 returns to the contact a side, the switch 74 switches again to the contact a side, and the switch 7
6 continues to be held in the closed state, and in the same operating manner as described above, the motor 4 slowly starts up, gradually increases its rotational speed until it reaches a preselected speed, and is driven at a constant rotation.

Further, the actuating arm 16 returns to the preset position by the first manual operation knob 13, the feed adjustment body 36 also rotates back together with the feed control lever 30, the feed control arm 32, etc., and the retaining pin 34 It is held in contact with the cam surface 25a of the feed adjustment body 25.

Therefore, desired sewing can be performed at the swing amplitude and cloth feed amount preset by the first and second manual operation knobs 13.23 and at the speed preset by the push buttons 8 to 9. .

When the sewing is completed, if the manual operation lever 40 is moved to the first position P1 as described above, the switch 7
6 is opened, the power supply to the motor 4 is cut off, and the sewing machine stops at the final position. However, if you want to perform tacking at the end of sewing, move the manual operation lever 40 to position P.
2 to position P3 again.

As a result, the operating arm 43 and the switching arm 47 are moved again to the position shown in FIG. 9, and the operating lever 63, switch operating cam body 71, etc. are rotated to the position for tacking as described above.
Tack stitching can be performed at low speed.

At this time, the first shaft cylindrical portion 4 of the shaft hinge 48 of the switching arm 47
8a comes into contact with the lower edge of the guide groove 60 of the locking arm 53, as shown by the two-dot chain line in FIG. When the first shaft cylindrical portion 48a abuts against the locking edge 58 of the locking arm 53 (the state shown by the solid line in FIG. 9), it assumes the same position.

After performing the required tacking stitches, the manual operation lever 40
When the pressure of
contacts the inclined portion 61 of the locking arm 53, causing the locking arm 53 to tilt against the action of the coil spring 55.

Therefore, the shaft pin 48 moves without being locked by the locking arm 53 and returns to the position shown in FIG. 4.

Therefore, the manual operating lever 40 passes through the second position P2 and returns to the first position P1, and the switch 76 is opened to stop the sewing machine at the normal position.

At this time, since the lever 40 passes through the second position P2, the changeover switch 75 switches to the contact a side with the switch 76 closed, and assuming that the selection switch 90 is closed, the moment The motor 4 tries to rotate at high speed, but the switch 74, which had been switched to the contact side during the above-mentioned tacking, is switched to the a side, so the capacitor 10
The transistor 103 is turned on by the 00 action, activating the bypass circuit, and the motor 4 remains in a low-speed driving state, and then, as described above, the switch 76 is opened and the power supply is cut off. be.

As is clear from the above explanation, the manual operation lever 4
When the lever 40 is pressed from the first position P1 to the second position P2 for stopping the sewing machine to the third position P3, the lever 40 can perform the holding stitch at the start of sewing at low speed.
When the pressure is released, it returns to the second position P2 and is held at that position, allowing normal sewing work to be carried out.If the operation lever 40 is then pressed again to move to the third position P3, sewing can be performed. The tacking stitch at the end can be performed at a low speed, and if the pressure on the operating lever 40 is released, the second position P is reached.
2 and returns to the first position P1 to stop the sewing machine.The manual operating lever 40 can be operated according to a series of programs, and the operating arm 43, switching arm 47, and The stop arm 53 and the like constitute a programming means for the manual operation lever 40.

If you wish to omit the above-mentioned tacking stitch at the start of sewing, move the manual operation lever 40 from the first position P1 to a position beyond the second position P2, and then move it to the third position P3. All you have to do is release the lever 40 before reaching
The lever 40 is thereby held in the second position P2.

Furthermore, if it is desired to omit the tacking stitch at the end of sewing, the manual operation lever 40 may be forcibly moved from the second position P2 toward the first position P1. is rotated independently of the switching arm 47 due to the presence of the fitting hole 43a, and the locking arm 53 of the switching arm 47 is rotated by the cooperative action of the operating protrusion 43a and the bent portion 62 of the locking arm 53.
When the locking action is released, the lever 40 returns to the first position P1, and the operating protrusion 43a, the bent portion 62, etc. constitute a releasing means for the programming means.

In addition, in the above-mentioned embodiment apparatus, the swinging movement of the needle bar is changed to zero for tacking, and the cloth feed amount is changed, but only one of these may be changed if necessary. Although it has practical effects, for example,
As described in Japanese Patent No. 8355, simply changing the swing amplitude of the needle bar to zero has a great practical effect, and in straight stitch sewing machines, only the material feed can be adjusted to an amount or direction suitable for lock stitching. Just change it.

As described in detail above, the present invention allows the rotational speed of the motor to be selected and set in advance by a speed setting means such as a push button and a selection switch that can be operated from outside the sewing machine frame. In a so-called electric sewing machine with a built-in controller, in which the drive of the motor is controlled by an operation, and the sewing machine is operated at a preset motor rotational speed after the motor is started, the manual operation unit controls the sewing machine. The sewing machine is configured to be able to selectively move to a first position for stopping operation, a second position for operating the sewing machine, and a further third position, and to the third position. When the manual operating body is operated to move, the motor is driven at a low speed regardless of the rotational speed set by the speed setting means, and the sewing machine can be operated simply by operating the manual operating body. It is possible to selectively control operation, stop, and tacking at the start or end of sewing, making it extremely easy to control the operation of the sewing machine.In particular, the tacking can be performed easily and reliably at low speeds, making the work easier. This will not make the person feel complicated, and the occurrence of excess or deficiency in the tacking can be reduced.

Further, it is possible to perform fastening at low speed by changing only the swing amplitude of the needle bar or the cloth feed amount as necessary, and to provide a practical low-speed fastening sewing device with a simple structure and low cost. Furthermore, it has many excellent practical effects, such as being applicable to linear sewing machines.

[Brief explanation of drawings]

The drawings show one embodiment embodying the present invention.
The figure is a perspective view showing the external appearance of the sewing machine, Figure 2 is a front view of the main parts with the machine frame removed, Figure 3 is a side view taken from the line ■-■ in Figure 2, and Figure 4 is manual operation. A partially enlarged front view for explaining the positioning mechanism of the part, FIG. 5 is a top view thereof,
Figure 6 is a side view of the same, Figure 7 is an electric circuit diagram, and Figure 8 is a side view.
Figures 10 to 10 are the fourth diagram for explaining different operating modes.
It is a front view corresponding to the figure. In the figure, 1 is the main shaft of the sewing machine, 4 is the electric motor, 8 to 10 are speed setting push buttons, 13 is the first manual operation knob,
15 is an adjustment plate, 16 is an operating arm, 17 is a linkage, 19 is a linkage lever, 23 is a second manual operation knob, 25 is a feed adjustment cam body, 30 is a feed control lever, 32 is a feed control arm,
35 is a feed adjustment shaft, 36 is a feed adjustment body, 40 is a manual operation lever, 43 is an operation arm, 47 is a switching arm, 50 is a switching lever, 53 is a locking arm, 63 is an operating lever, 68 is a rotating lever , 71 is a switch operating cam body, 74 to 76 are switches, and 90 to 92 are speed setting selection switches.

Claims (1)

[Claims] 1. An electric motor for driving the main shaft of a sewing machine, a motor drive circuit for supplying electric power to the motor, and a motor connected to the motor drive circuit for presetting the rotational speed of the motor. a speed setting means that can be manually operated from outside the sewing machine frame; and a sewing machine frame for operating the motor drive circuit to operate the sewing machine at the motor rotational speed set by the speed setting means and for stopping the operation. A manual operation unit body that can be manually operated from the outside, an amplitude adjuster that can be operated from outside the sewing machine frame to control the lateral swing movement of the needle bar, and an amplitude adjuster that can be operated from the outside of the sewing machine frame to control the feed movement of the feed dog. In an electric sewing machine equipped with a feed adjuster that can be operated from outside the frame, the manual operation member has a first position for stopping operation of the sewing machine, a second position for operating the sewing machine, and a further different position. positioning means acting on the manual operating body for selective movement to a third position; When the manual operating body is moved to the third position, at least one of the regulators is temporarily moved from the operating position set by operation from outside the sewing machine frame to an operating position suitable for tacking. a linking means disposed in the motor drive circuit for temporarily operating the motor at a low speed regardless of the setting state of the speed setting means when the manual operation member is operated to move to the third position; a low-speed drive means that is activated to drive the electric motor, and even if the motor drive circuit is preset to a state in which the electric motor is driven at high speed by the speed setting means, the A tacking device characterized in that tacking can be performed at low speed by moving the device to the third position.