JP2922321B2 - Needle bar top dead center control device in sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for regulating a top dead center of a needle bar in a sewing machine.

2. Description of the Related Art The needle bar during sewing of a sewing machine repeatedly moves up and down with a predetermined stroke. When the sewing stops, the engagement between the needle bar and its driving member is released, and the needle bar is sewn by a spring force. The stalks are evacuated to the top dead center. This secures a space between the tip of the sewing needle (or the tip of the presser foot) attached to the lower end of the needle bar and the upper surface of the sewing machine table when sewing is stopped, which hinders work such as re-closing the cloth. It is considered not to cause.
However, with the diversification of sewing work, there is a demand for securing the above space larger. In order to meet this demand, the following means (a) and (b) are generally considered. (A) The stroke of the needle bar at the time of sewing is set to be large, and its top dead center, that is, the retracted position is made higher. (B) The needle bar at the time of retreat is held at a position higher than the top dead center at the time of sewing without changing the stroke at the time of sewing.

[0002]

In the case of the above means (a), the needle bar at the time of sewing is caused to perform useless operation,
In addition, vibration and noise increase with the vertical movement with a large stroke. According to the means (b), although the problem of the means (a) is solved, when the needle bar is retracted at the time of sewing stop, the engaging portion of the needle bar to the driving member is
The drive member is located above the top dead center. Therefore, in order to restart the sewing operation, it is necessary to hold down the needle bar so that it can be engaged with the driving member by pushing down to the top dead center position at the time of sewing. It is practically impossible for an operator to perform such a procedure every time sewing is restarted, and even more so in a multi-head industrial sewing machine having a large number of sewing heads.

[0003] The technical problem of the present invention is that the stroke of the needle bar at the time of sewing can be minimized, and when the sewing is stopped, the needle bar can be largely retracted above the top dead center at the time of sewing as required. In addition, a process of switching the needle bar from the retracted state to the sewing restart state can be easily performed.

[0004]

Means for Solving the Problems To solve the above-mentioned problems, a needle bar upper dead center regulating device in a sewing machine according to the present invention is configured as follows. That is, the sewing machine includes a needle bar that can be operated in the vertical direction and is constantly urged upward by a spring force, and a needle bar driving member that is driven up and down in conjunction with the rotation of the main shaft of the sewing machine. The needle bar and the needle bar drive member are kept engaged with each other to move the needle bar up and down by the vertical drive of the needle bar drive member, and when sewing is stopped, the engagement between the needle bar and the needle bar drive member is released to release the spring force. In a sewing machine that can retreat the needle bar upward with the
And stopper available-needle bar stopper receives the head against the a first position in which the needle bar can be regulated in a position substantially corresponding to a top dead center at the time of the sewing, the needle bar than the first position above the Regulate position
It is displaceably provided to each of the second position possible.

[0005]

In this configuration, when sewing is stopped, the sewing machine moves to the second position.
Displaced needle bar stopper receives needle bar head
By this, the needle bar at this time can be restricted to a position largely retracted above the top dead center at the time of sewing . In addition, sewing
When it resumed by displacing the needle bar stopper to the first position, to regulate the position approximately corresponding to the top dead center of the stroke at the time of sewing needle bar and thereby interlocked with the vertical drive of the needle bar drive member The vertical movement of the needle bar is started smoothly .
Thus even Oite set vertically stroke minimum needle bar during sewing, the lower end of the needle bar during sewing stop
Between the sewing needle, etc. attached to the
A sufficient space can be secured in between, and work such as re-closing of cloth can be performed without any trouble.

[0006]

Next, an embodiment of the present invention will be described with reference to the drawings. In the following embodiment, the apparatus of the present invention is applied to a multi-head, multi-needle sewing machine having a large number of sewing heads and each sewing head having a large number of needle bars. FIG.
The entire sewing machine is shown in an external perspective view. In this drawing, the table 2
A large number of sewing heads H are provided along the longitudinal direction of the sewing machine frame 10 which is long in the width direction. The embroidery frame 4 mounted on the upper surface of the sewing machine table 2 is driven in the X and Y directions by control based on embroidery data, as is well known. By the frame driving and the sewing operation of the sewing head H, a predetermined embroidery sewing is performed on the cloth (not shown) stretched on the embroidery frame 4.

FIGS. 1 and 2 each show one of the sewing machine heads H in a sectional view, and FIG. 3 also shows one of the sewing machine heads H in a front view. In these drawings, a sewing machine head H includes a sewing machine arm 12 fixed to a sewing machine frame 10 and a needle bar case 14 attached to a front portion of the arm 12. The needle bar case 14 has a plurality of needle bars 1 as shown in FIG.
8 are mounted so as to be able to move up and down. The needle bar case 14 can be slid along the front surface of the sewing machine arm 12. Only one needle bar 18 selected by this sliding operation is driven up and down by receiving a driving force from a needle bar driving member 42 described later.

At the lower end of each needle bar 18, a sewing needle 3 is provided.
2 is attached by the needle stopper 30. These needle bars 1
A needle bar holder 20 having a protruding portion 22 is fixed to a substantially middle position of the needle bar case 8 on the rear side (left side in FIGS. 1 and 2) of the needle bar case 14. A needle bar spring 24 is attached to the outer periphery of each needle bar 18 between the spring seat 34 fixed to the upper end of each needle bar 18 and the upper surface of the horizontal frame 14a of the needle bar case 14. ing. Each needle bar 18 is urged upward by the needle bar spring 24. With this urging force, when the needle bar 18 described later is retracted (see the solid line state in FIG. 1), the upper surface of the needle bar holder 20 is held in a state received by the cushion 28 on the lower surface of the horizontal frame 14a. In addition, a head 36 having a spherical upper surface is attached to the upper end of each needle bar 18. As shown in FIG. 2, the head 36 is attached to a connecting pin 38 integrally protruding from the upper surface of the spring seat 34 so as to be vertically adjustable. The head 36 is fixed at an arbitrary vertical adjustment position by tightening a screw (not shown) from the outer peripheral side of the head 36 toward the coupling pin 38. The needle bar 18 is provided with a cloth presser body 60 which can be moved up and down relative to the needle bar 18, and a needle bar through a cloth presser spring 66 provided between the upper surface of the cloth presser body 60 and the needle bar holder 20. It is assembled so as to follow the up-down movement of the motor.

A single base needle bar 40 is arranged on the sewing machine arm 12 in parallel with each needle bar 18. A drive base 41 and a needle bar driving member 42 are provided on the axis of the base needle bar 40.
Are mounted so as to be able to move up and down along the base needle bar 40 while maintaining an integral relationship with each other. This needle bar driving member 42
On the side facing the needle bar 18, a pair of upper and lower engaging projections 44 are integrally formed. These engaging projections 4
The protrusion 22 of the needle bar holder 20 of the one needle bar 18 selected as described above is engaged between the four. On the other hand, the main shaft 50 of the sewing machine disposed to penetrate the sewing machine arm 12 of each sewing machine head H is driven to rotate by a drive motor (not shown). A needle bar drive cam 52 is fixed on the shaft of the sewing machine main shaft 50 together with other drive cams. The rotation of the needle bar drive cam 52 causes the drive base 41 to move up and down along the base needle bar 40 together with the needle bar drive member 42 through the needle bar drive link mechanism 54.

The needle bar drive member 42 is rotatable about the axis of the base needle bar 40 with respect to the drive base 41. In addition, a cam surface 46 is formed on the outer surface of the needle bar driving member 42 as shown in FIGS. When a jump signal based on embroidery data or the like is input to the cam surface 46, an end of a solenoid armature (both not shown) or the like is positioned so as to be in contact therewith. In this case, the needle bar driving member 42 rotates around the axis of the base needle bar 40 as it rises, and its top dead center position (solid line position in FIG. 2).
In the vicinity, the engagement of the engagement projection 44 with the projection 22 of the needle bar 18 is released.

FIG. 4 is a plan view of the sewing head H. As is apparent from FIG. 4, a single needle bar stopper 70 is disposed on the upper surface of the sewing machine arm 12. The needle bar stopper 70 is for receiving the raising operation of the needle bar 18 selected by the slide of the needle bar case 14 as described above, and includes a base arm 74 and a tip arm 76. A base end of the base arm 74 is rotatably supported by a support shaft 72 with respect to a shaft support bracket 12 a of the sewing machine arm 12. A receiving member 80 protruding downward is fixed to an end of the tip arm 76. This receiving member 80
Is located opposite the head 36 of the selected needle bar 18. The base arm 74 and the distal arm 76
Are connected to each other by two screws 78.
By loosening these screws 78, the vertical movement of the distal end arm 76 with respect to the base arm 74, that is, the receiving member 80
Can be adjusted up and down.

A cam shaft 86 is rotatably inserted into the sewing machine arm 12 of each sewing head H above the base arm 74 of the needle bar stopper 70.
A cam 88 is fixed on a portion of the cam shaft 86 facing the base arm 74. The cam 88 has a first cam surface 88a and a second cam surface 88b on its outer peripheral surface. The needle bar stopper 70 receives an urging force in the direction of pressing the base arm 74 against the cam 88 by the torsion spring 82. Therefore, when the cam 88 is in the rotation position of FIG. 1, the base arm 74 is pressed against the second cam surface 88b of the cam 88, and the needle bar stopper 70 is at the position indicated by the solid line in FIG. When the cam 88 is in the rotation position in FIG. 2, the base arm 74 is pressed against the first cam surface 88a of the cam 88, and the needle bar stopper 70 is in the position in FIG.

The receiving member 8 of the needle bar stopper 70 held in the state shown in FIG. 2 by the first cam surface 88a of the cam 88.
Numeral 0 is a position substantially corresponding to the top dead center position (solid line position in FIG. 2) of the vertical stroke of the needle bar 18 at the time of sewing, and the head 36 of the needle bar 18 can be received and regulated to that position. This is referred to as a first position of the needle bar stopper 70. The needle bar stopper 70 held by the second cam surface 88b of the cam 88 in the state of the solid line in FIG. 1 can allow the needle bar 18 to rise to the position of the solid line in FIG. This is referred to as a second position of the needle bar stopper 70. The base arm 74 when the needle bar stopper 70 is at the first position in FIG.
Is pressed against the receiving plate 84 fixed to the sewing machine arm 12 by the first cam surface 88a of the cam 88,
Positioning is performed so that no rattling occurs. In this state, even if a pushing load is applied to the receiving member 80 of the needle bar stopper 70 from the needle bar 18 side, the load does not act as a force for rotating the cam 88.
Positional relationship between receiving member 80 and cam 88 and first cam surface 8
The shape of 8a is considered.

One end of a rotating arm 90 is fixed to the cam shaft 86 as shown in FIGS.
The other end of the rotating arm 90 is connected to a connecting lever 92 by a pin 94. Rotation of a main shaft (both not shown) of a geared motor or the like fixed to the inner wall surface of the sewing machine frame 10 is performed on the connection lever 92 via a rotation arm (not shown) fixed to the main shaft. It is transmitted as a reciprocating motion. Due to this reciprocating operation, the cam shaft 86 is rotated through the rotating arm 90, whereby the cam 88 is rotated to the state shown in FIG. 1 or FIG.

In the above construction, when the needle bar driving cam 52 rotates together with the sewing machine main shaft 50 during sewing of the sewing machine, the drive base 41 and the needle bar driving member 42 move along the base needle bar 40 through the needle bar driving link mechanism 54. To repeat the vertical movement. As a result, one needle bar 18 selected as described above moves up and down between the top dead center shown by the solid line in FIG. 2 and the bottom dead center shown by the virtual line in FIG. Following this, the cloth presser body 60 also moves up and down. At the time of this sewing, the needle bar stopper 70 is at the first position shown in FIG. Here, when the above-described jump signal is input, the needle bar driving member 42 rotates around the axis of the base needle bar 40 based on the input, and the engagement projection 44
Is disengaged from the projection 22 of the needle bar 18. The needle bar 18 thus released from the restriction by the needle bar driving member 42
The head 36 is received by the receiving member 80 of the needle bar stopper 70 at the first position, while receiving the upward biasing force due to the elasticity of the needle bar spring 24. Is held at a position substantially corresponding to the top dead center during sewing. Therefore, when the jump is released, when the needle bar driving member 42 has risen toward the top dead center shown by the solid line in FIG. 2, the engaging projection 44 and the projection 22 of the needle bar 18 are engaged again. The needle bar driving member 42 once rotates around the axis of the base needle bar 40 and returns so as to be aligned.
Therefore, thereafter, the vertical movement of the needle bar 18 is restarted.

When the sewing machine stops, the jump signal is transmitted and the engaging projection 4 of the needle bar driving member 42 is moved.
After the engagement between the needle bar drive member 4 and the protrusion 22 of the needle bar 18 is released, the rotation of the sewing machine spindle 50 is stopped in a state where the needle bar drive member 42 is lowered to the position shown by the solid line in FIG. It is set as follows. Accordingly, the needle bar 18 when the sewing machine stops is received by the receiving member 80 of the needle bar stopper 70 at the first position in FIG. 2 and the head 36 is held at a position substantially corresponding to the top dead center at the time of sewing. I have.

When the sewing is stopped based on the end or stop code, the cam 88 is moved from the state shown in FIG. 2 to the state shown in FIG. 1 by a signal accompanying the sewing operation or by a switch operation for changing the cloth or manually moving the embroidery frame 4. To rotate. As a result, the needle bar stopper 70 is displaced to the second position shown by the solid line in FIG. At this time, the needle bar 18 is moved by the urging force of the needle bar spring 24 to the head 36.
Is kept in contact with the lower surface of the receiving member 80 of the needle bar stopper 70 and rises following the displacement of the needle bar stopper 70.
The upper surface of the needle bar holder 20 has a cushion 28 on the lower surface of the horizontal frame 14 a in the needle bar case 14.
1 to the retracted position. At this time, the operation for selecting the needle bar 18 by sliding the needle bar case 14 described above is possible, and a large space is provided between the upper surface of the sewing machine table 2 and the tip of the cloth presser body 60 in this state. Is secured. This makes it easy to change the cloth.

After the preparation for the next sewing is completed, the operator normally slides the bar 98 shown in FIG. 5 along the axis thereof to switch the switch box 96 to restart the sewing machine. Change the switch inside. At this time, prior to the start of rotation of the sewing machine spindle 50, the cam 8
The needle bar stopper 70 is displaced to the first position while pushing down the head 36 of the needle bar 18 with the receiving member 80 thereof. As a result, the needle bar 18 is pushed down from the retracted position shown by the solid line in FIG. 1 to a position shown by the virtual line, that is, a position substantially corresponding to the top dead center at the time of sewing, and is held at that position. . Thereafter, when the rotation of the sewing machine main shaft 50 is started, the needle bar driving member 42 once lowers from the solid line position in FIG. 1 to the bottom dead center position indicated by the virtual line in FIG. From the upper dead center, the engaging projection 44 and the projection 22 of the needle bar 18 are engaged again. Thus, the needle bar 18 starts moving up and down, and sewing is started. If the sewing is stopped by operating the bar 98, the needle bar 18
It is only necessary to evacuate.

As described above, an embodiment of the present invention has been described with reference to the drawings. However, the present invention is not limited to this embodiment, and includes various embodiments. For example, the cam shaft 86 is divided for each sewing machine head H, and the rotation of these cam shafts 86 is controlled by an individual geared motor or the like, or the needle bar of each sewing machine head H by eliminating the cam shaft 86 and the cam 88. If the stopper 70 is configured to be directly displaced to the first position and the second position by the operation of a solenoid or the like, the needle bar 18 can be retracted and released for each sewing machine head H. In this case, as long as the needle bar 18 is retracted, even if the needle bar driving member 42 reaches the top dead center of the driving stroke, the engaging protrusion 44 is not attached to the sewing head H that has received the above-described jump signal. The projection 22 of the needle bar 18 does not engage with the needle bar 18, thereby eliminating the need for jump control.

In the above embodiment, a multi-needle sewing machine in which each sewing head H has a large number of needle bars 18 has been described as an example, but the sewing head H has only one needle bar. Needless to say, the above-described function can be obtained also when the needle bar stopper 70 is employed in the single-needle sewing machine described above. In a multi-needle sewing machine, as described above, the needle bar 1 is used for thread change (for example, color change of embroidery thread).
The needle bar case 14 is slid while the needle bar 8 is retracted to select the needle bar 18. For this purpose, it is necessary to hold the needle bar 18 at the time of retreat at the top dead center position where the upper surface of the needle bar holder 20 is received by the cushion 28 on the lower surface of the horizontal frame 14a, like the other needle bars 18 remaining. . On the other hand, in the single-needle sewing machine, even at the top dead center of the needle bar 18 when the needle bar 18 is retracted, the position of the needle bar 18 can be regulated by receiving the head 36 with the receiving member 80 of the needle bar stopper 70. That is, the needle bar stopper 70 in this case also functions as a substantial stopper for the needle bar 18 at the second position. In other words, with a one-needle sewing machine,
No stopper is required by the zero and the cushion 28 on the lower surface of the horizontal frame 14a.

[0021]

As described above, according to the present invention, when the sewing machine stops sewing, the needle bar can be largely retracted above the top dead center of the stroke at the time of sewing as required. It is easy to switch to the sewing resumption state, so the stroke of the needle bar at the time of sewing is minimized, and at the time of sewing stop, a sufficient space is secured between the tip of the sewing needle and the upper surface of the sewing machine table. Work such as cloth replacement can be performed without any trouble.

[Brief description of the drawings]

FIG. 1 is a sectional view of a sewing head in a state where a needle bar is retracted when sewing is stopped.

FIG. 2 is a sectional view of the sewing head during sewing.

FIG. 3 is a front view of the sewing head during sewing.

FIG. 4 is a plan view of the sewing head during sewing.

FIG. 5 is an external perspective view of a multi-head, multi-needle sewing machine.

[Explanation of symbols]

 18 Needle bar 24 Needle bar spring 42 Needle bar drive member 50 Sewing machine spindle 70 Needle bar stopper

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) D05B 1/00-83/00

Claims (1)

(57) [Claims] 1. A needle bar which can be moved in the vertical direction and is constantly urged upward by a spring force, and a needle bar driving member which is driven up and down in conjunction with rotation of a main shaft of the sewing machine. During sewing, the needle bar and the needle bar driving member are held in the engaged state, and the needle bar is vertically moved by the vertical driving of the needle bar driving member,
In capable during sewing stop be retracted needle bar upward by the spring force to release the engagement between the needle bar and the needle bar drive member sewing machine receives its head against upward movement of the needle bar and stopper available-needle bar stopper, a first position in which the needle bar can be regulated in a position substantially corresponding to a top dead center at the time of the sewing, the second position can be regulated to a position above the first position the needle bar A needle bar control device for a needle bar in a sewing machine, wherein the device is provided so as to be displaceable to each of the following.