JPH04292193A - Top dead center controller for needlebar in sewing machine - Google Patents

Abstract

PURPOSE:To minimize the stroke of a needlebar, and to secure the sufficient space between the tip of a sewing needle, etc., and the upper face of a sewing machine table at the time when sewing is stopped by constituting the device so that the needlebar can be displaced to each of a first position for controlling it to a position corresponding to the top dead center, and a second position which can allow the needlebar to ascend to a saving position. CONSTITUTION:At the time when sewing is stopped, a cam 88 is turned by a switch operation, etc. In this case, a needlebar 18 ascends by following the displacement of a needlebar stopper 70, in a state that the head part 36 is brought into contact with the lower face of a receiving member 80 of the needlebar stopper 70 by energizing force of a needlebar spring 24. Subsequently, the needlebar 18 reaches a saving position in which the upper face of its needlebar connecting stud 20 is received by a cushion 28 of the lower face of a horizontal frame 14a in a needlebar case 14. In this case, a selecting operation of the needlebar 18 by a slide of the needlebar case 14 is allowed.

Description

[Detailed description of the invention]

0001

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

[Prior Art] When a sewing machine is sewing, the needle bar repeatedly moves up and down with a predetermined stroke, but when sewing is stopped, the needle bar and its driving member are disengaged, and the needle bar is sewn by a spring force. It is evacuated to the top dead center of the stroke. As a result, when sewing is stopped, a space is secured between the tip of the sewing needle attached to the lower end of the needle bar (or the tip of the presser foot) and the top surface of the sewing machine table, which hinders work such as relining the fabric. Care has been taken to ensure that this does not occur. However, with the diversification of sewing operations, there is a desire to secure a larger space. Therefore, in order to meet this demand, the following means (a) and (b) are generally considered. (a) The stroke of the needle bar during sewing is set larger to make its top dead center, that is, the retracted position, higher. (b) The needle bar during retraction is held at a position higher than the top dead center during sewing without changing the stroke during sewing.

0002

[Problem to be Solved by the Invention] In the case of the above-mentioned means (a), the needle bar is forced to make unnecessary movements during sewing.
Furthermore, vibration and noise also increase due to the vertical movement with a large stroke. According to the means (b), the means (
Although the problem a) is solved, if the needle bar is retracted when sewing is stopped, the engagement portion of the needle bar with the drive member is located above the top dead center of the drive member. Therefore, in order to restart the sewing operation, it is necessary to push the needle bar down to the top dead center position during sewing and hold it so that it can engage with the drive member. In reality, it is impossible for an operator to carry out such a procedure every time sewing is restarted, especially in a multi-head industrial sewing machine equipped with a large number of sewing machine heads.

The technical problem of this invention is to minimize the stroke of the needle bar during sewing, and to make it possible to retract the needle bar far above the top dead center during sewing as necessary when sewing is stopped. Moreover, it is an object of the present invention to easily perform the process of switching the needle bar from the retracted state to the resuming state of sewing.

0004

[Means for Solving the Problems] In order to solve the above problems, the needle bar top dead center regulating device in the sewing machine of the present invention is constructed as follows. In other words, it has a needle bar that can move vertically and is always urged upward by a spring force, and a needle bar drive member that is driven vertically in conjunction with the rotation of the main shaft of the sewing machine. The rod and the needle bar drive member are kept engaged and the needle bar is moved 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 and the spring force is applied. In a sewing machine in which the needle bar can be retracted upward at the time of sewing, a needle bar stopper that can receive the rising movement of the needle bar and regulate its position moves the needle bar to a position that approximately corresponds to the top dead center during sewing. The needle bar is provided so as to be movable to a first position in which the needle bar can be restricted to the above-mentioned retracted position, and a second position in which the needle bar is allowed to rise to the retracted position above the first position.

[0005]

[Operation] In this configuration, if the needle bar stopper is moved to the second position when sewing is stopped and the engagement between the needle bar and the needle bar driving member is released, the needle bar will move from the top dead center during sewing. is also regulated to a position that is greatly retracted upward. Therefore, sufficient space is ensured between the tip of the sewing needle attached to the lower end of the needle bar and the upper surface of the sewing machine table, so that operations such as changing the fabric can be performed without any hindrance. When sewing is resumed, the needle bar stopper is moved to the first position, so that the needle bar is held at a position substantially corresponding to the top dead center position of the sewing stroke. Therefore, the needle bar starts to move up and down in conjunction with the up and down movement of the needle bar drive member. The vertical stroke of the needle bar during sewing may be set to the minimum necessary.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, the apparatus of the present invention is applied to a multi-head, multi-needle type sewing machine that is equipped with a large number of sewing machine heads and each sewing machine head is provided with a large number of needle bars. Figure 5
The entire sewing machine is shown in a perspective view. In this drawing, on the sewing machine table 2, this table 2
A large number of sewing machine heads H are provided along the longitudinal direction of the sewing machine frame 10, which is arranged long in the width direction. Further, the embroidery frame 4 assembled 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 this frame drive and the sewing operation of the sewing machine head H, a predetermined embroidery stitch is performed on the cloth (not shown) stretched on the embroidery frame 4.

FIGS. 1 and 2 each show a cross-sectional view of one of the sewing machine heads H, and FIG. 3 similarly shows a front view of one of the sewing machine heads H. In these drawings, the sewing machine head H includes a sewing machine arm 12 fixed to a sewing machine frame 10 and a needle bar case 14 assembled to the front surface of this arm 12. The needle bar case 14 has a plurality of needle bars 1 as shown in FIG.
8 are assembled to be able to move up and down, respectively. 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, which will be described later.

A sewing needle 3 is provided at the lower end of each needle bar 18.
2 is attached with a needle clamp 30. These needle bars 1
A needle bar holder 20 having a protruding portion 22 is fixed to the rear side of the needle bar case 14 (on the left side in FIGS. 1 and 2) at approximately the middle position between the upper and lower sides of the needle bar case 8 . Further, a needle bar spring 24 is assembled on the outer periphery of each needle bar 18 between a 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. Due to this biasing force, when the needle bar 18 is retracted (see the solid line state in FIG. 1), which will be described later, the upper surface of the needle bar holder 20 is held in a state where it is received by the cushion 28 on the lower surface of the horizontal frame 14a. Moreover, a head 36 having a spherical upper surface is attached to the upper end of each needle bar 18. As is clear from FIG. 2, the head 36 is attached to a coupling pin 38 that integrally projects from the upper surface of the spring seat 34 so as to be vertically adjustable. Then, by tightening a screw (not shown) from the outer circumferential side of the head 36 toward the coupling pin 38, the head 36 is fixed at an arbitrary vertical adjustment position. Each needle bar 18 is provided with a presser foot 60 that can be moved up and down relative to each other, and is connected to the needle bar via a presser spring 66 provided between the upper surface of the presser foot 60 and the needle bar holder 20. It is assembled to follow the vertical movement of 18.

On the sewing machine arm 12, one basic needle bar 40 is arranged parallel to each needle bar 18. On the axis of this base needle bar 40, a drive base 41 and a needle bar drive member 42 are provided.
are assembled so as to be movable up and down along the base needle bar 40 while maintaining an integral relationship with each other. This needle bar driving member 42
A pair of upper and lower engagement protrusions 44 are integrally formed on the side facing the needle bar 18. These engaging protrusions 4
4, the protruding portion 22 of the needle bar holder 20 of one needle bar 18 selected as described above engages with the space between the needle bars 4 and 4. On the other hand, the sewing machine main shaft 50, which is disposed to pass through the sewing machine arm 12 of each sewing machine head H, is rotationally driven by a drive motor (not shown). A needle bar drive cam 52 is fixed on the shaft of the sewing machine main shaft 50 along with other drive cams. This 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. Moreover, a cam surface 46 is formed on the outer surface of the needle bar driving member 42, as shown in FIGS. 1 and 2. An end of a solenoid armature (none of which is shown) is positioned so as to be able to come into contact with this cam surface 46 when a jump signal based on embroidery data or the like is input. In this case, the needle bar drive member 42 rotates around the axis of the base needle bar 40 as it rises, and is attached to the protruding portion 22 of the needle bar 18 near its top dead center position (solid line position in FIG. 2). The engaging protrusion 4
4 is disengaged.

FIG. 4 shows a plan view of the sewing machine head H. As is clear from FIG. 4, a single needle bar stopper 70 is arranged on the upper surface of the sewing machine arm 12. The needle bar stopper 70 is for receiving the upward movement of the needle bar 18 selected by sliding the needle bar case 14 as described above, and is composed of a base arm 74 and a tip arm 76. The base end portion of the base arm 74 is rotatably supported by a support shaft 72 with respect to the pivot bracket 12a of the sewing machine arm 12. Further, a receiving member 80 projecting downward is fixed to the end of the tip arm 76. This receiving member 80 is positioned opposite to the head 36 of the selected needle bar 18 . Note that the base arm 74 and the tip arm 76 are connected to each other by two screws 78. By loosening these screws 78, the tip arm 76 can be adjusted up and down with respect to the base arm 74, that is, the receiving member 80 can be adjusted vertically with respect to the base arm 74.
can be adjusted up and down.

A cam shaft 86 is rotatably inserted into the sewing machine arm 12 of each sewing machine head H above the base arm 74 of the needle bar stopper 70. A cam 88 is fixed on the camshaft 86 at a location 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 a biasing force from a torsion spring 82 in the direction of pressing its base arm 74 against a cam 88. Therefore, when the cam 88 is in the rotational position shown in 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 in the position shown by the solid line in FIG. When the cam 88 is in the rotating position shown 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 shown in FIG.

The receiving member 8 of the needle bar stopper 70 is held in the state shown in FIG. 2 by the first cam surface 88a of the cam 88.
0 is a position that approximately corresponds to the top dead center position (solid line position in FIG. 2) of the vertical stroke of the needle bar 18 during sewing, and the head 36 of the needle bar 18 can be received and regulated at that position. This is called the first position of the needle bar stopper 70. Further, the needle bar stopper 70, which is held in the solid line position in FIG. 1 by the second cam surface 88b of the cam 88, allows the needle bar 18 to rise to the solid line position in FIG. This is called the second position of the needle bar stopper 70. Note that when the needle bar stopper 70 is in the first position shown in FIG. It is positioned so that no sticking occurs. In this state, even if a push-up load is applied to the receiving member 80 of the needle bar stopper 70 from the needle bar 18 side, the receiving member 80 and the cam 88 are Positional relationship with and first cam surface 88
The shape of a is taken into consideration.

One end of a rotating arm 90 is fixed to the camshaft 86, as shown in FIGS. 3 to 5.
The other end of the rotating arm 90 is connected to a connecting lever 92 with a pin 94. The connection lever 92 is connected to the rotation arm (not shown) of a main shaft (not shown) of a geared motor or the like fixed to the inner wall surface of the sewing machine frame 10 through a rotation arm (not shown) fixed to the main shaft. It is transmitted as a reciprocating motion. This reciprocation causes the camshaft 86 to rotate through the rotating arm 90, thereby rotating the cam 88 to the state shown in FIG. 1 or 2.

In the above configuration, when the sewing machine is sewing, when the needle bar drive cam 52 rotates together with the sewing machine main shaft 50, the drive base 41 and the needle bar drive member 42 are moved along the base needle bar 40 through the needle bar drive link mechanism 54. Repeat the up and down movement. As a result, the needle bar 18 selected as described above moves up and down between the top dead center indicated by the solid line in FIG. 2 and the bottom dead center indicated by the imaginary line in FIG. Following this, the presser foot 60 also moves up and down. During this sewing, the needle bar stopper 70 is in the first position shown in FIG. 2. When the jump signal mentioned above is input here, the needle bar drive member 42 rotates around the axis of the base needle bar 40 based on this, and the engagement protrusion 44
The engagement between the needle bar 18 and the protrusion 22 is released. The needle bar 18 released from the restraint by the needle bar drive member 42 in this way is subjected to an upward biasing force by the elasticity of the needle bar spring 24, but the needle bar 18 is in the position where the head 36 is in the first position. The needle bar 18 is received by the receiving member 80 of the stopper 70, so that the needle bar 18 during jumping is held at a position substantially corresponding to the top dead center during sewing. Therefore, when the jump is released, when the needle bar drive member 42 rises toward the top dead center indicated by the solid line in FIG. This needle bar driving member 4
2 rotates once around the axis of the base needle bar 40 and returns. Therefore, the vertical movement of the needle bar 18 is resumed thereafter.

When the sewing machine stops, the jump signal is transmitted and the engaging protrusion 4 of the needle bar driving member 42 is activated.
4 is disengaged from the protrusion 22 of the needle bar 18, the sewing machine main shaft 50 stops rotating with the needle bar drive member 42 lowered to the position shown by the solid line in FIG. It is set as follows. Therefore, when the sewing machine is stopped, the head 36 of the needle bar 18 is received by the receiving member 80 of the needle bar stopper 70 in the first position in FIG. 2, and is held at a position approximately corresponding to the top dead center during sewing. There is.

Now, when sewing is stopped based on the end or stop code, the cam 88 is changed from the state shown in FIG. 2 to the state shown in FIG. Rotate it. 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 toward the head 36 by the biasing force of the needle bar spring 24.
is raised following the displacement of the needle bar stopper 70 while keeping it in contact with the lower surface of the receiving member 80 of the needle bar stopper 70. The upper surface of the needle bar holder 20 of the needle bar 18 is a cushion 28 on the lower surface of the horizontal frame 14a in the needle bar case 14.
It reaches the position indicated by the solid line in FIG. 1, that is, the retracted position. At this time, the needle bar 18 can be selected by sliding the needle bar case 14 as described above, and there is a large space between the top surface of the sewing machine table 2 and the tip of the presser foot 60 in this state. is ensured. This makes it easy to change the fabric.

After the preparation for the next sewing is completed, the operator usually slides the bar 98 shown in FIG. 5 along its axis and presses the switch box 96 to restart the sewing machine. Change the switch inside. At this time, before the sewing machine main shaft 50 starts rotating, the cam 88
is rotated again to the state shown in FIG. 2, and the needle bar stopper 70 is displaced to the first position while pressing down the head 36 of the needle bar 18 with its receiving member 80. As a result, the needle bar 18 moves from the retracted position shown by the solid line in FIG. 1 to the position shown by the imaginary line.
That is, it is pushed down to a position that approximately corresponds to the top dead center during sewing and is held at that position. After that, the sewing machine main shaft 50
When the rotation of the needle bar drive member 42 starts, the needle bar driving member 42 moves from the solid line position in FIG. 1 to the bottom dead center position shown by the imaginary line in FIG. When reaching near the dead center, the engaging protrusion 44 and the protrusion 2 of the needle bar 18
2 are engaged again. As a result, the needle bar 18 begins to move up and down, and sewing begins. Note that when sewing is stopped by operating the bar 98, the needle bar 18 may be retracted as necessary.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited to this embodiment and includes various embodiments. For example, the camshaft 86 may be divided for each sewing machine head H, and the rotation of these camshafts 86 may be controlled by individual geared motors, or the camshaft 86 and cam 88 may be abolished and the needle bar of each sewing machine head H may be controlled separately. If the stopper 70 is configured to be directly moved 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 of the sewing machine head H that has received the jump signal is retracted, even if the needle bar drive member 42 reaches the top dead center of its drive stroke, the engaging protrusion 44 will not move. The protrusion 22 of the needle bar 18 does not engage with the needle bar 18, thereby eliminating the need for jump control.

Further, the above embodiments have been explained using a multi-needle type sewing machine in which each sewing machine head H is equipped with a large number of needle bars 18, but it is assumed that each sewing machine head H is equipped with only one needle bar 18. It goes without saying that the above-described function can also be obtained when the needle bar stopper 70 is employed in a single-needle sewing machine. Note that in multi-needle sewing machines, the needle bar 1 is
The needle bar 18 is selected by sliding the needle bar case 14 with the needle bar 8 retracted. To do this, it is necessary to hold the needle bar 18 during retraction 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 remaining needle bars 18. . On the other hand, in a single-needle type sewing machine, even when the needle bar 18 is at the top dead center when it is retracted, the head 36 of the needle bar 18 is received by the receiving member 80 of the needle bar stopper 70, so that the position of the needle bar 18 can be regulated. That is, the needle bar stopper 70 in this case functions as a substantial stopper for the needle bar 18 even in its second position. In other words, on a single-needle sewing machine, the needle bar holder 2
0 and the cushion 28 on the lower surface of the horizontal frame 14a becomes unnecessary.

[0021]

As described above, according to the present invention, when the sewing machine stops sewing, the needle bar can be retracted far above the top dead center of the stroke during sewing, and moreover, the needle bar can be retracted from this retracted state. Since it is easy to switch to the state where sewing resumes, the stroke of the needle bar during sewing should be kept to the minimum necessary, and when sewing is stopped, sufficient space should be ensured between the tip of the sewing needle and the top surface of the sewing machine table. You can perform tasks such as reupholstering the fabric without any problems.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a sewing machine head with a needle bar retracted when sewing is stopped.

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

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

FIG. 4 is a plan view of the sewing machine 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 main shaft 70 Needle bar stopper

Claims (1)

[Claims] Claim 1: A needle bar capable of vertical movement and always urged upward by a spring force, and a needle bar driving member that is driven vertically in conjunction with rotation of a sewing machine main shaft. During sewing, the needle bar and the needle bar driving member are kept engaged and the needle bar is moved up and down by the up and down movement of the needle bar driving member, and when sewing is stopped, the engagement between the needle bar and the needle bar driving member is released. In a sewing machine in which the needle bar can be retracted upward by the spring force, a needle bar stopper that can receive the rising movement of the needle bar and regulate its position keeps the needle bar at the top dead center during sewing. The needle bar is provided so as to be movable to a first position where the needle bar can be regulated to a substantially corresponding position, and a second position where the needle bar is allowed to rise to the retracted position above the first position. A device for regulating the top dead center of the needle bar on a sewing machine.