JP2853316B2 - sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a sewing machine having a function of driving a needle bar and a shuttle by different motors and setting the shuttle to an initial position. .

(Prior Art) In recent years, sewing machines that drive the needle bar and the shuttle by different motors have been considered in consideration of diversification of the design of the sewing machine and multifunctionality. In such a sewing machine, there is no mechanical interlock between the needle bar and the shuttle, and they can move independently of each other. When the power is turned off, the needle bar can be moved by hand independently of the shuttle. Therefore, there is a possibility that the synchronous relationship between the needle bar and the shuttle is deviated. Therefore, to restore the synchronous relationship between the needle bar and the shuttle after turning on the power,
You need to set them to the initial position.

(Problems to be Solved by the Invention) By the way, at the time of sewing, the shuttle rotates in synchronization with the vertical movement of the needle bar, so that the loop formed on the upper thread by the lowering of the sewing needle is hooked by the point of the shuttle. The sewing is performed by repeating the operation of passing the lower thread through the loop of the upper thread. Therefore, when the shuttle is set to the initial position after the power is turned on, the needle thread may already be hooked on the blade point of the shuttle. In this state, when setting the shuttle to the initial position, there is no problem if the upper thread is smoothly pulled out to the shuttle as the shuttle rotates.However, before turning on the power, the needle bar can be moved manually. Depending on the position of the needle bar, the needle thread may be constrained by the thread tension, etc., and the upper thread may not be smoothly drawn out to the shuttle when the initial position of the shuttle is set. A condition can occur. In this state, when the initial position is set, the rotation of the shuttle is locked by the upper thread hooked on the sword tip of the shuttle, causing a problem that the shuttle cannot be set to the initial position.

The present invention has been made in view of such circumstances, and accordingly, it is an object of the present invention to provide a sewing machine that can reliably set the shuttle to an initial position even when the needle thread is caught on the blade point of the shuttle. It is in.

[Structure of the Invention] (Means for Solving the Problems) A sewing machine according to the present invention, in which a needle bar and a shuttle are driven by different motors respectively, wherein a shuttle position detecting means for detecting a rotation position of the shuttle, sewing is performed. Initial position setting means for energizing the hook driving motor based on the output signal of the hook position detecting means before starting to rotate the hook to the initial position,
When the initial position setting means is energized so as to rotate the hook driving motor forward during the initial position setting and normally rotates the hook to the initial position, the initial position setting operation is terminated at that position. If the shuttle does not normally rotate forward and does not reach the initial position, the shuttle driving motor is controlled to rotate in the reverse direction to reverse rotate the shuttle to the initial position.

(Operation) At the time of setting the initial position of the shuttle, the initial position setting means first energizes the shuttle drive motor to rotate forward, thereby rotating the shuttle forward. At this time, if the rotation of the shuttle is not locked by the upper thread, the shuttle normally rotates forward to the initial position, and the initial position setting operation ends at that position. On the other hand, when the hook is hooked on the upper thread and does not normally rotate normally, the shuttle driving motor is rotated in reverse to rotate the shuttle in reverse. This reverse rotation causes the hook point of the shuttle to be released from the upper thread, so that the shuttle is reversely rotated to the initial position without being disturbed by the upper thread, and the initial position setting operation ends at that position.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

The shuttle 1 is arranged horizontally in a sewing machine bed (not shown). A bobbin (not shown) around which a bobbin thread is wound is mounted in the shuttle 1, and during sewing, the shuttle 1 is rotated in synchronization with the vertical movement of a needle bar (not shown) to rotate the needle. The loop formed on the upper thread by the lowering of the bar (not shown) is hooked by the blade point 1a of the shuttle 1, and the operation of passing the lower thread through the loop of the upper thread is repeated to perform sewing. The rotary shaft 2 supporting the shuttle 1 is rotatably supported via a bearing 4 on a mounting plate 3 fixed in the sewing machine bed. Further, a gear 5 is fitted on the rotating shaft 2. On the other hand, on the lower surface side of the mounting plate 3, a shuttle driving motor 6 is fixed with the rotating shaft 7 facing upward, and a gear 8 fitted on the upper end of the rotating shaft 7 is connected to the gear 5 on the shuttle 1 side. The rotation of the shuttle drive motor 6 is transmitted to the shuttle 1 via both the gears 8 and 5. In this case, a pulse motor capable of normal rotation and reversal is employed as the hook driving motor 6, and when the excitation coil is energized with X pulses (for example, 40 pulses), the hook 1 rotates once. I have.

On the side of the shuttle 1, an optical sensor 9 serving as a shuttle position detecting means is mounted on a sensor base 10 fixed to the mounting plate 3. The optical sensor 9 is constituted by a transmission type photoelectric switch in which a light projecting element 9a and a light receiving element 9b are vertically opposed to each other. Correspondingly, the rotation trajectory of the fan-shaped shutter 11 fixed to the shuttle 1 is set so as to cross the optical path between the light projecting element 9a and the light receiving element 9b of the optical sensor 9. In this case, the position where the end 11b of the shutter 11 of the shuttle 1 interrupts the optical path between the light emitting element 9a and the light receiving element 9b of the optical sensor 9 is the position of the shuttle 1
In this initial position, the optical sensor 9 outputs an initial position detection signal (high-level signal) to the control circuit 13.

On the other hand, the needle bar and the balance (both not shown) are driven by a needle bar drive motor 12 (see FIG. 2). The control circuit 13 for controlling the motor 12 for driving the needle bar and the motor 6 for driving the shuttle includes a microcomputer (not shown) for executing an initial position setting program shown in FIG. It also functions as initial position setting means for rotating. The control circuit 13 includes a power switch 14, a sewing start
A stop switch 15, an optical sensor 9 for detecting the hook position, and a needle position detector 16 are connected.

In this case, in order to set the shuttle 1 to the initial position after the power is turned on, the microcomputer of the control circuit 13 controls the initial position setting operation as follows according to the initial position setting program shown in FIG. When the user turns on the power switch 14, first, the balance is lowered to the lowest point, and the upper thread is fed out to the shuttle 1 (step P1). The reason for this is to prevent the tension of the upper thread from being applied to the shuttle 1 as much as possible. At this time, the needle bar is stopped at a position where the needle bar slightly passes through the lowermost point (a position where the blade point 1a of the shuttle 1 scoops the upper thread). Thereafter, the hook driving motor 6 is rotated forward (rotated in the direction of arrow A) one step at a time (steps P2, P
3) Rotate shuttle 1 forward (rotate in the direction of arrow B). At this time, while the shuttle 1 does not reach the initial position,
11 does not enter the optical sensor 9, the output voltage of the optical sensor 9 maintains the low level, and the initial position detection signal (high level signal) is not output. In this case, the operation of rotating the hook driving motor 6 forward one step at a time is repeated (step P4).

Regardless of the position of the shuttle 1 before the initial position is set, the shuttle 1 always reaches the initial position before the shuttle 1 makes one revolution. If the exciting coil of the hook driving motor 6 receives a pulse of a number X corresponding to one rotation of the hook 1 (40 pulses in this embodiment).
If the shuttle 1 does not reach the initial position even when the pulse is energized, the shuttle 1 is locked by being hooked on the upper thread and cannot rotate normally.

Therefore, in this embodiment, the motor 6 is rotated forward by one step until the number of pulses to be supplied to the excitation coil of the motor 6 for driving the shuttle becomes a number X (40) corresponding to one rotation of the shuttle 1. (Steps P2 and P3). During that time, if the shuttle 1 reaches the initial position, "YES" is determined in Step P4, and the initial position setting operation ends at that position. In this case, when the shuttle 1 reaches the initial position, the shutter 11 enters the optical sensor 9 and blocks the optical path between the light emitting element 9a and the light receiving element 9b. A signal (high-level signal) is output to the control circuit 13.

On the other hand, if the excitation coil of the hook driving motor 6 is energized with a number X of pulses corresponding to one rotation of the hook 1 (40 pulses in this embodiment), and the hook 1 does not reach the initial position, 1 is locked by being hooked on the upper thread. In this case, "YES" is determined in the step P2, and the process shifts to a step P5, in which the hook driving motor 6 is rotated in reverse by one step (rotation in the direction of arrow C), and the hook 1 is rotated in reverse (arrow D Direction). By this reverse rotation,
Since the hook point 1a of the shuttle 1 comes off the upper thread and the locked state of the shuttle 1 is released, the shuttle 1 is rotated in the reverse direction without being disturbed by the upper thread. The reverse rotation of the shuttle 1 is performed until an initial position detection signal (high level signal) is output from the optical sensor 9, that is, one end 11a of the shutter 11 enters the optical sensor 9, and the light emitting element 9a and the light receiving element 9a receive light. This process is repeated until the optical path between the element 9b and the element 9b is interrupted (steps P5 and P6). In this manner, even after the one end 11a of the shutter 11 enters the optical sensor 9, the hook driving motor 6 is further rotated in the reverse direction by one step (Step P7), and the initial position detection signal is output from the optical sensor 9. It is determined whether or not the shutter 11 is in a state of blocking the optical path of the optical sensor 9 (step P8). If the shutter 11 is still blocking the optical path of the optical sensor 9, the shuttle driving motor 6
Is repeatedly rotated by one step (steps P7 and P8), thereby temporarily rotating the shuttle 1 to a position where the shutter 11 is slightly extracted from the optical sensor 9 (a position immediately before the initial position). Thereafter, conversely, the hook driving motor 6 is rotated forward by one step (step P
9) It is determined whether or not the initial position detection signal is output from the optical sensor 9, that is, whether or not the other end 11b of the shutter 11 has entered the optical sensor 9 (step P10). . If the other end 11b of the shutter 11 has not yet entered the optical sensor 9, the operation of rotating the shuttle driving motor 6 forward by one step is further repeated (steps P9 and P10). ,Shutter
The shuttle 1 is rotated forward to a position (initial position) where the other end 11b of the eleventh 11 enters the optical sensor 9. Thereby, the pot 1
Is accurately set to the initial position, and the initial position setting operation ends. After this, raise the balance to the highest point (step
P11), Set the needle bar to the initial position.

According to the above embodiment, if the rotation of the shuttle 1 is not locked by the upper thread when the initial position is set, the shuttle 1 normally rotates forward to the initial position, and the initial position setting operation ends at that position. On the other hand, when the hook 1 is caught on the upper thread and does not rotate normally, the hook driving motor 6 is rotated in the reverse direction to rotate the shuttle 1 in the reverse direction.
The hook 1a of the shuttle 1 is disengaged from the upper thread to release the locked state of the shuttle 1, and the shuttle 1 is reversely rotated to the initial position without being disturbed by the upper thread. For this reason, at the start of the initial position setting operation, even if the needle thread is hooked on the blade point 1a of the shuttle 1, the shuttle 1 can be reliably set to the initial position.

In the above embodiment, the circumferential pitch of the shutter 11 is set so that the lock and the step-out of the hook driving motor 6 can be easily detected.
Since the angle of rotation of the hook 1 in one step of the hook driving motor 6 (hereinafter referred to as "one step angle") is set to be larger, when the initial position is set by rotating the hook 1 in the reverse direction, Then, the shutter 11 is reversely rotated to a position past the optical sensor 9 (steps P7 and P8), and then is rotated forward to set the end 11b of the shutter 11 to a position (initial position) where it enters the optical sensor 9. I am trying to do it. However, the present invention is not limited to such an embodiment, and the shutter 11 may be formed to be narrow (for example, about one step angle). In this case, it is possible to omit the steps P7 to P10. it can.

Further, in the above embodiment, the shuttle position detecting means (optical sensor 9) is constituted by a transmission type photoelectric switch, but may be constituted by another optical sensor such as a reflection type photoelectric switch. The magnet 1 is attached to the kettle 1 by detecting the magnetism of the magnet with magnetic detecting means such as a Hall sensor.
May be configured to detect the initial position.

In addition, the present invention can be variously modified, for example, the rotation transmission structure between the shuttle driving motor 6 and the shuttle 1 may be appropriately changed.

[Effects of the Invention] As is apparent from the above description, the present invention, when the hook is hooked on the upper thread and does not rotate normally at the initial position setting, causes the hook driving motor to rotate in the reverse direction to rotate the shuttle in the reverse direction. As a result, the hook of the hook is released from the upper thread to release the locked state of the hook by the reverse rotation of the shuttle, and the shuttle is reliably rotated to the initial position without disturbing the upper thread. . For this reason, at the start of the initial position setting operation, even if the upper thread is caught on the hook point of the shuttle, the shuttle can be reliably set to the initial position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of the present invention. FIG. 1 is a perspective view of a peripheral structure of a shuttle, FIG. 2 is a block diagram showing an electric schematic configuration, and FIG. It is a flowchart which shows the control content at the time of initial position setting of a shuttle. In the drawings, reference numeral 1 denotes a shuttle, 6 denotes a shuttle drive motor, 9 denotes an optical sensor (hook position detection means), 11 denotes a shutter, 12 denotes a needle bar drive motor, and 13 denotes a control circuit (initial position setting means).

Claims (1)

(57) [Claims] 1. A sewing machine for driving a needle bar and a shuttle by different motors, respectively. A shuttle position detecting means for detecting a rotational position of the shuttle, and a sewing machine based on an output signal of the shuttle position detecting means before sewing starts. Initial position setting means for energizing a driving motor to rotate the shuttle to an initial position, wherein the initial position setting means energizes the hook driving motor to rotate forward at the time of initial position setting. When the hook is normally rotated forward to the initial position, the initial position setting operation is terminated at that position, and when the hook does not reach the initial position without normal rotation, the hook driving motor is rotated reversely. A sewing machine wherein the shuttle is controlled to rotate in the reverse direction to an initial position.