JP2570696Y2 - Actuation mechanism of torsion hook of binding machine - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a method of grasping a part of a wire loop formed by being wound around a material to be bound (for example, a plurality of reinforcing bars) with a torsion hook and twisting a plurality of times. The present invention relates to a torsion hook operating mechanism of a binding machine that binds a material to be bound.

[0002]

2. Description of the Related Art A torsion hook operating mechanism of a binding machine of the type described above is known from Japanese Patent Publication No. 3-60989. According to this torsion hook operating mechanism, a chuck that slides in the axial direction is arranged on the outer periphery of the torsion hook support shaft that pivotally supports the torsion hook, and the torsion hook is moved by the cam in the axial direction with respect to the torsion hook support shaft. Open and close.

[0003] According to the binding machine described in Japanese Patent Publication No. 3-60989, after the binding operation consisting of a series of steps is completed,
The torsion hook needs to be stopped at a predetermined angular position.
For this reason, the torsion hook support shaft is rotated in the reverse direction after the completion of the binding operation to open the torsion hook, and at the same time, to contact the torsion hook contact member. The rotation of the torsion hook contact shaft causes the reverse rotation of the torsion hook support shaft. To block. Thereby, the torsion hook is stopped at the predetermined angle position. The torsion hook contact member is
Since the torsion hook contact member is arranged at a position close to the member to be bound in the binding machine, the torsion hook contact member may hit the material to be bound during the binding operation and may be damaged.

[0004]

[Problem to be solved by the present invention]
In order to eliminate the drawbacks of the binding machine described in Japanese Patent Application Laid-Open Publication No. HEI 10-406, the present applicant has filed an application for a torsion hook operating mechanism of the binding machine according to Japanese Patent Application No. 4-40687. This torsion hook operating mechanism continuously supplies a bundling wire to an arcuate guide arranged in front of a wire supply mechanism, and winds a wire fed from the tip of the arcuate guide a plurality of times around a material to be tied. A wire ring is formed, and a part of the wire ring is grasped and twisted by a torsion hook which is rotated forward and backward by a hook drive motor. A hook drive shaft connected to the hook drive shaft via a speed reducer and a torsional hook support shaft disposed in front of the hook drive shaft are coaxially and relatively rotatably connected to form a spiral groove on the outer peripheral surface of the hook drive shaft. , A torsion hook having a long hole is pivotally supported on the hook support shaft so as to be openable and closable, and a sleeve is arranged on the outer peripheral surface of the hook drive shaft and the torsion hook support shaft,
The sleeve is rotatable within a certain range with respect to the hook drive shaft and is also movable in the axial direction, and is fixed in the rotation direction with respect to the torsion hook support shaft and is movable in the axial direction within a certain range. And inside the sleeve,
A housing portion of a spherical ball partially engaged with the spiral groove is formed, and a pin that loosely fits with the long hole of the torsion hook is fixed near the tip of the sleeve. Are formed, and a forward rotation stopper and a reverse rotation stopper that engage with these projections to prevent forward rotation and reverse rotation of the sleeve are arranged on the body of the binding machine near the outer peripheral surface of the sleeve.

When the hook drive shaft rotates forward, the projection engages with the forward rotation stopper to prevent forward rotation of the sleeve, thereby moving the sleeve axially forward together with the ball.
Rotate the torsion hook in the closing direction, remove the protrusion from the forward rotation stopper at the front end of the axial movement range of the sleeve,
The sleeve and the hook drive shaft are integrally rotated forward. When the hook drive shaft rotates in the reverse direction, the projection and the reverse rotation stopper engage to move the sleeve axially to the standby position.

Normally, the torsion hook is positioned at right angles to a part of the wire loop around the material to be tied and in an open state immediately before the torsion operation. The torsion hook is closed so as to grasp a part of the wire loop by advancing the sleeve by the forward rotation of the hook drive motor at the start of the torsional operation, and then twisting the wire loop a plurality of times by rotating forward, and the diameter thereof. And wrap it around the outer periphery of the material to be tied. After the twisting operation is completed, the torsion hook is opened by the reverse rotation of the hook driving motor to release the wire ring. Thereafter, the torsion hook is reversed to the initial angular position and then retracts to the standby position. This allows
The binding machine ends one cycle of the binding operation.

According to the binding machine disclosed in Japanese Utility Model Application No. 4-40687, the sleeve for controlling the opening and closing and rotation of the torsion hook is connected to the hook drive shaft via the ball which is loosely fitted in the spiral groove. When the rotation of the hook drive shaft is stopped, the hook drives forward by the forward rotation of the hook drive shaft, and moves backward by the reverse rotation of the hook drive shaft. Therefore, the torsion hook is
After the torsion is completed, if the wire is hooked on the wire ring wound around the outer peripheral portion of the material to be bound and the reverse rotation is prevented, the sleeve retreats to the standby position in an open state without returning to the initial angular position. When the sleeve retracts to the standby position,
The hook drive motor stops, and one cycle of the binding operation ends. Therefore, the torsion hook starts the next cycle of the binding operation at a position deviating from the initial angular position.

When the hook drive motor is started at the start of the next cycle of the binding operation, the hook drive shaft also rotates forward.
Be started. At this time, the sleeve does not follow the rotation of the hook drive shaft due to its inertia at the time of rest, but is pushed forward in the axial direction through the ball in the spiral groove. As a result, the torsion hook that is out of the initial angular position does not face a part of the wire loop at right angles, and sometimes a part of the wire loop cannot be grasped. In this case, the twist hook cannot perform the twisting operation, and the binding machine causes a binding error.

Therefore, an object of the present invention is to ensure that even when the torsion hook is out of the initial angular position and is in the standby position, the torsion hook securely secures a part of the wire loop formed around the material to be bound. An object of the present invention is to provide a torsion hook operating mechanism of a binding machine that can be grasped.

[0010]

According to the present invention, a wire is continuously supplied to an arc-shaped guide arranged at a front end of a binding machine main body.
The wire fed from the tip of the arc-shaped guide is wound around the material to be bound to form a wire ring, and a part of the wire ring is grasped and twisted by a torsion hook driven by a hook drive motor, In a binding machine for binding materials to be bound, a hook support shaft is coaxially and relatively rotatably connected to a front end of a hook drive shaft rotated by a hook drive motor, and a spiral groove is formed on an outer peripheral surface of the hook drive shaft. The sleeve is externally inserted into the hook drive shaft and the torsion hook support shaft, and the sleeve is rotatable and axially movable within the range of the spiral groove with respect to the hook drive shaft. The sleeve is rotatable and axially movable within the range of the spiral groove, and a housing for a spherical ball engaging with the spiral groove is formed inside the sleeve. The torsion hook which is opened and closed by the axial movement of the sleeve is pivotally supported by the hook support shaft, and a plurality of protrusions are formed on the outer peripheral surface of the sleeve in the circumferential direction. A control device that is disposed on the binding machine body, engages with the projections, prevents forward rotation and reverse rotation of the sleeve, and controls starting and stopping of the hook drive motor, with a torque smaller than the static friction of the sleeve. The hook drive motor is controlled to start so that the hook drive shaft rotates forward. When the hook drive motor starts rotating forward, the sleeve rotates forward together with the hook drive shaft, and the projection engages with the forward rotation stopper to rotate the hook drive shaft. Is positioned at the initial angular position, and then, in the process of further normal rotation of the hook drive shaft, the sleeve is advanced by engagement of the protrusion with the normal rotation stopper, and the wire is moved at the initial angular position. Close the torsion hook in the direction that grasps, remove the projection from the forward rotation stopper at the front end of the axial movement range of the sleeve, rotate the sleeve and the hook drive shaft integrally forward, and when the hook drive shaft is It is characterized in that the protrusion and the reverse rotation stopper engage to retract the sleeve to the standby position.

[0011]

According to the present invention, the rotation of the hook drive motor at the time of startup is a speed at which the hook drive shaft rotates forward with a torque smaller than the static friction of the sleeve. No relative rotation occurs. The sleeve rotates forward by the forward rotation of the hook drive shaft,
After the torsion hook is moved to the initial angular position, the torsion hook is stopped by the engagement of the projection and the forward rotation stopper, moves forward, and closes the torsion hook. At this time, the torsion hook faces the wire loop at right angles, and the grip of the wire loop is ensured. As a result, a binding error does not occur.

[0012]

FIG. 1 shows the internal structure of a binding machine. A binding wire 3 wound around a bobbin 2 disposed at a rear end (left end in FIG. 1) of the main body 1 is attached to the substantially T-shaped main body 1.
A wire supply mechanism a which is arranged at the upper end of the main body 1, a wire supply mechanism a which is arranged at the front end (right end in FIG. 1) of the main body 1 and continuously supplies an arc-shaped curved guide 5, and is fed out from the tip of the curved guide 5. A torsion hook 8 grasps and twists a part of a wire ring 3a formed by winding a plurality of times around a material 6 to be tied (for example, a plurality of rebars); Wire feeding mechanism a and wire twisting mechanism b
A control device (for example, a microcomputer chip) that controls the rotation of the wire feed motor 10 and the hook drive motor 7 of the wire supply mechanism a and the wire twisting mechanism b based on the signals from the sensor provided in the controller and the trigger switch 9. Is provided.

The wire supply mechanism a has a wire feed motor 10 which is a normal DC motor provided inside the rear end of the main body 1. The drive shaft of the wire feed motor 10 is
It is connected to a wire feed drive roller 13 via a reduction gear 11. The wire feed drive roller 13 feeds the wire 3 from the bobbin 2 to the linear guide 4 in cooperation with a wire feed driven roller (not shown).

The curved guide 5 has an arc-shaped fixed frame 14. As shown in FIGS. 1 and 2, the fixed frame 14 includes a frame body 14 a having a U-shaped cross section and a frame body 14.
The frame a includes a spring receiver 14b facing the inner surface of the frame body 14a at a rear portion in the wire running direction and a front portion in the wire running direction. A movable plate 16 having substantially the same overall shape as the frame body 14a is disposed between the frame body 14a and the spring receiver 14b. The movable plate 16 includes a spring receiver 14 b and the movable plate 16.
Are biased so as to be pressed against the frame main body 14a by a compression coil spring 15 disposed between them. In the vicinity of the inner surface of the movable plate 16, an arc-shaped guide groove 17 that is open to the side (toward the frame body 14a) is formed. The guide groove 17 is
When guiding the wire 3, a wire guide passage whose side is closed by the frame body 14a is formed.

When the wire 3 passes through the guide groove 17,
It is plastically deformed into an arc shape, is fed out from the front end of the curved guide 5, forms a one-turn ring around the material 6 to be bound, and again enters the guide groove 17 from the rear end of the curved guide 5, A plurality of (for example, three) wire rings 3a are formed around the material 6 to be tied. At this point, the wire 3 is cut by a wire cutting mechanism c described later. After cutting the wire 3, the wire ring 3a tilts the movable plate 16 to the position shown by the broken line against the spring force of the compression coil spring 15 by the force of the worker separating the binding machine from the material 6 to be bound. The side of the groove 17 is opened and separated from the curved guide 5.

As shown in FIG. 1, a wire cutting mechanism c is arranged above the front end of the main body 1. The connecting portion between the straight guide 4 and the curved guide 5 includes a shear cutter 18.
Is arranged. The shear cutter 18 is used for the linear guide 4.
The guide 19 is rotated by a rod 19 extending along the axis and a link plate 20 connected to the rear end of the rod 19.
The wire 3 is sheared in cooperation with a wire guide 40 disposed between the rear end of the linear guide 4 and the front end of the linear guide 4. The link plate 20 is formed with an operating piece 21 extending downward and operatively linked to the wire twisting mechanism b.

The reduction gear 11 of the wire feed motor 10
The number of rotations of the reduction gear 11 is detected by a wire feed amount sensor 22 including a magnet 22a fixed to the outer peripheral portion and a Hall element 22b fixed to the main body 1. When the wire feed amount sensor 22 reaches a predetermined amount (ie, a predetermined number of rotations of the reduction gear 11), the wire feed amount sensor 22
A predetermined wire feed amount detection signal is output. When receiving the predetermined wire feed amount detection signal, the control device stops the wire feed motor 10 and starts the hook drive motor 7 of the wire twisting mechanism b by start control.

The wire torsion mechanism b moves the torsion hook 8 in the axial direction between the standby position and the operating position by the hook drive motor 7. The twisting hook 8 of the wire twisting mechanism b advances from the standby position to the operating position while the hook driving motor 7 is rotating forward, grasps a part of the wire ring 3a and twists, while the hook driving motor 7 rotates in the reverse direction. During this operation, the wire retracts from the operating position to the standby position and releases the twisted wire ring 3a.

The wire torsion mechanism b has a hook drive shaft 24 connected via a speed reduction mechanism 23 to a drive shaft of a DC motor type hook drive motor 7 disposed substantially at the center of the main body 1.
(See FIG. 3), and a hook support connected at the front end of the hook drive shaft 24 to the hook drive shaft 24 via a ball coupling mechanism 24a comprising a spherical ball and an annular groove, coaxially moving forward and backward, and relatively rotatable. And an axis 25. The tip of the hook support shaft 25 is formed as a yoke, and pivotally supports the substantially L-shaped torsion hook 8 in a freely openable / closable manner by a pivot 8a. A sleeve assembly 26 is fitted around the outer periphery of the connection between the hook drive shaft 24 and the hook support shaft 25. As shown in FIG.
, The main body 1 has a forward rotation stopper 27 and a reverse rotation stopper 28 which engage with the projection 34 of the sleeve assembly 26.
And are arranged. As shown in FIG. 3, a spiral groove 29 is formed on the outer peripheral surface of the distal end portion of the hook drive shaft 24 within a certain range in the axial direction of the hook drive shaft 24.
An elongated hole 30 is formed in the center of the torsion hook 8.

The sleeve assembly 26 has a structure in which an outer sleeve 26a and an inner sleeve 26b fitted inside the outer sleeve 26a are integrally pin-connected (not shown). The sleeve assembly 26 is rotatable with respect to the hook drive shaft 24 and is capable of moving forward and backward, while being rotatable integrally with the hook support shaft 25 and is capable of moving forward and backward.

In the vicinity of the rear end of the inner sleeve 26b, there is formed a ball accommodating portion 39 for accommodating two balls 31 loosely fitted into the spiral groove 29 at positions opposed to each other in the circumferential direction of the inner sleeve 26b. . The ball housing 39 has a structure in which a retaining ring is fitted into a circular hole formed at a position facing the inner sleeve 26b in the circumferential direction. At the tip of the outer sleeve 26a, a pair of cutouts 33 that allow the torsion hook 8 to open and close are formed at positions facing the outer sleeve 26a in the circumferential direction. Further, a claw 26c for grasping the wire ring 3a in cooperation with the tip of the torsion hook 8 is formed at the tip of the outer sleeve 26a.

As best shown in FIG. 3B, a plurality (for example, four) of projections 34 are provided on the outer peripheral surface of the rear end of the outer sleeve 26a at equal intervals in the circumferential direction. I have. In the axial direction of the sleeve assembly 26, only one projection 34 a is replaced by the other three projections 3.
Longer than 4b. The forward rotation stopper 27 and the reverse rotation stopper 28 are attached to the main body 1 via a bracket 35. As shown in FIG. 4B, the forward / reverse rotation stoppers 27 and 28 are pivotable in a direction to close each other, and are urged in a direction to open each other by a torsion coil spring. The reverse rotation stopper 28 is located axially forward of the sleeve assembly 26 with respect to the normal rotation stopper 27.

When the sleeve assembly 26 rotates in the reverse direction, the projection 34 moves over the normal rotation stopper 27, and when the sleeve assembly 26 rotates in the normal direction, the projection 34 engages with the normal rotation stopper 27 to prevent the sleeve assembly 26 from rotating in the normal direction. I do. On the other hand, the protrusion 34
When the sleeve assembly 26 rotates in the reverse direction, the reverse rotation stopper 2
8 to prevent the sleeve assembly 26 from rotating in the reverse direction.
Get over 7.

When the hook drive shaft 24 rotates forward when the wire twisting mechanism b is at the standby position, the projection 34
a engages with the forward rotation stopper 27 to prevent the sleeve assembly 26 from rotating forward. For this reason, the sleeve assembly 26
It advances from the standby position to the operating position together with the pair of balls 31, and during that time, the torsion hook 8 is turned in a direction to close with respect to the leg 26c to grasp a part of the wire ring 3a. At this time,
The pair of balls 31 is at the front end of the spiral groove 29, and the engagement between the forward rotation stopper 27 and the projection 34a is released. From now on,
The hook drive shaft 24 rotates forward integrally with the sleeve assembly 26, and the torsion hook 8 twists the wire ring 3a. When the hook drive motor 7 rotates in the reverse position in the operating position, first, any one of the protrusions 34 engages with the reverse rotation stopper 28 to prevent the sleeve assembly 26 from rotating.

As shown in FIG. 1, an overhanging plate 37 that extends in the radial direction is fixed to the rear end of the sleeve assembly 26. A magnet 38a is fixed to the rear surface of the overhang plate 37. On the other hand, a Hall element 38b is disposed on the front surface of the cover of the speed reduction mechanism 23. The standby position sensor 38 is constituted by the magnet 38a and the Hall element 38b. The standby position sensor 38 detects that the sleeve assembly 26 (that is, the torsion hook 8) is at the standby position. The overhang plate 37 is freely engageable with the operation piece 21 of the link plate 20.

The operation of the torsion hook operating mechanism will be described below. When the operator arranges the curved guide 5 around the material 6 to be bound and presses the trigger switch 9, the wire feed motor 10 is started, and the wire supply mechanism a places a predetermined amount of the wire 3 around the material 6 to be bound. The wire ring 3a supplied and wound a plurality of times is formed. Next, according to the sequence set by the control device, the hook drive motor 7 starts and rotates forward.

The control device activates the hook drive motor 7 in the following manner. That is, the hook drive motor 7
Are started and stopped by turning on / off a switching element that performs a switching operation in response to a drive signal from a control device. When the hook drive motor 7 is started, a drive signal having a pulse waveform is output from the control device to the switching element, and the switching element is turned on and off with a very short width, thereby supplying a small effective power to the hook drive motor 7. As shown by the solid line in FIG. 11C, the rotation speed of the hook drive motor 7 is reduced as compared with the case where there is no activation control indicated by the dashed line. For example, after the start signal of the hook drive motor 7 is output, for about 0.1 second,
The switching element is driven so as to output a pulse waveform drive signal having an ON time width of 5 μs and an OFF time width of 200 μs. As a result, the hook drive shaft 24 rotates with a torque smaller than the static friction of the sleeve assembly 26,
The sleeve assembly 26 also rotates integrally with the hook drive shaft 24,
The torsion hook 8 is rotated up to about 180 °. During the rotation of the torsion hook 8, the projection 34 a and the normal rotation stopper 2
7 and is positioned at the initial angular position. After a lapse of 0.1 seconds from the activation of the hook drive motor 7, a continuous ON signal is output from the control device to the switching element, and the hook drive motor 7 rotates normally. Thereafter, the wire twisting mechanism a performs a normal operation.

The sleeve assembly 26 is prevented from rotating by the engagement between the projection 34a and the normal rotation stopper 27, and moves forward. The advance of the sleeve assembly 26 causes the torsion hook 8
Closes the leg 26c and grasps a part of the wire ring 3c. During this time, the extension plate 37 also advances, and the link plate 20 is rotated via the operation piece 21. As a result, the shear cutter 18 is rotationally driven with respect to the wire guide 40, the wire guide 40 and the wire passage in the shear cutter 18 are displaced, and the wire 3 is sheared immediately before the rear end of the curved guide 5. You.

When the ball 31 reaches the front end of the spiral groove 29, the projection 34a of the sleeve assembly 26 comes off the normal rotation stopper 27. Thereafter, the sleeve assembly 26
The torsional hook 8 twists the wire ring 3a a plurality of times by rotating integrally with the hook drive shaft 24. During this time, the protrusion 34 of the sleeve assembly 26 allows the torsion hook 8 to rotate forward while getting over the reverse rotation stopper 28.

When the wire is twisted a predetermined number of times, the load torque of the torsional hook drive motor 7 sharply increases. The load torque that has risen sharply is applied to a load torque sensor (not shown).
Is detected by Upon receiving the load torque detection signal, the control device rotates the torsional hook drive motor 7 in the reverse direction.
As a result, the sleeve assembly 26 also moves the hook drive shaft 24
It is reversed together with. However, any one of the protrusions 34 of the sleeve assembly 26 abuts on the reverse rotation stopper 28 within the range of 1/4 rotation of the sleeve assembly 26, thereby preventing the sleeve assembly 26 from rotating in the reverse direction. In the case of the present embodiment, the projection 34 is
Since the four sleeve assemblies 26 are provided at equal intervals in the circumferential direction, the maximum reverse rotation amount of the sleeve assembly 26 is 90 °. Therefore, the twisted portion of the wire ring 3a is not excessively twisted back by the reverse rotation of the torsion hook 8.

By preventing the sleeve assembly 26 from reversing, the sleeve assembly 26 begins to retreat, and first,
Open the torsion hook 8 (see FIG. 7). Further, when the sleeve assembly 26 is retracted, the protrusion 34b is moved to the reverse rotation stopper 28.
And the sleeve assembly 26 reverses until the projection 34a engages the reverse stop 28. When the protrusion 34a engages with the reverse rotation stopper 28 (see FIG. 8), the torsion hook 8
Returns to the initial angular position, and thereafter, the sleeve assembly 26 retreats to the standby position (see FIG. 9).
This is detected by the standby position sensor 38. The control device stops the torsional hook drive motor 7 according to the detection signal from the standby position sensor 38. Even when the torsion hook 8 does not return to the initial angle position, as described above, the torsion hook 8 returns to the initial angle position by controlling the activation of the hook drive motor 7 in the next cycle of the binding operation.

In the above embodiment, the torsion hook 8 is
Although it was almost L-shaped, as shown in FIG.
A pair of torsion hooks 8a that are symmetrical and open and close with each other may be used.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional side view of an internal structure of a binding machine having a torsion hook operating mechanism according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIGS. 3A and 3B are a longitudinal sectional view and a transverse sectional view, respectively, of a main part of a wire twisting mechanism of the binding machine of FIG.

FIGS. 4 (a) and (b) are a side view and a front view, respectively, of the wire twisting mechanism immediately after activation at a standby position.

FIGS. 5 (a) and (b) are a side view and a front view, respectively, of a wire twisting mechanism which reaches an operating position and grasps a wire loop.

FIGS. 6A and 6B are a side view and a front view of the wire twisting mechanism immediately after the hook drive motor starts reverse rotation after the wire twisting operation is completed.

FIGS. 7A and 7B are a side view and a front view, respectively, of the wire twisting mechanism with the twisting hook opened.

FIGS. 8A and 8B are a side view and a front view, respectively, of the wire twisting mechanism in a state where the twist hook returns to an initial angular position.

FIGS. 9A and 9B are a side view and a front view, respectively, of the wire twisting mechanism in a state returned to a standby position.

FIG. 10 is a plan view of a torsion hook according to another embodiment.

FIG. 11 shows (a), (b) and (c)
FIG. 4 is a waveform diagram of a start signal of a hook drive motor, a drive signal of a hook drive motor, and a rotation speed of the hook drive motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bundling machine main body 3 Wire 3a Wire ring 5 Arc guide 6 Material to be tied 7 Hook drive motor 8 Torsion hook 24 Hook drive shaft 25 Hook support shaft 26 Sleeve assembly 27 Forward rotation stopper 28 Reverse rotation stopper 29 Spiral groove 31 Spherical ball 34 Projection 39 Ball housing

Claims (1)

(57) [Scope of request for utility model registration] 1. A wire ring is formed by continuously supplying a wire to an arc-shaped guide disposed at a front end of a binding machine main body, and winding a wire fed from a tip of the arc-shaped guide around a material to be bound. In a binding machine for binding a material to be bound by grasping and twisting a part of this wire loop with a torsion hook driven by a hook drive motor, a hook support shaft is attached to a front end of the hook drive shaft rotated by the hook drive motor. Are connected coaxially and rotatably relative to each other, a spiral groove is formed on the outer peripheral surface of the hook drive shaft, a sleeve is externally inserted into the hook drive shaft and the torsion hook support shaft, and the sleeve is connected to the hook drive shaft. On the other hand, it is rotatable and movable in the axial direction within the range of the spiral groove, is rotatable and integral with the hook support shaft, and is movable in the axial direction within the range of the spiral groove. A housing portion for a spherical ball engaging with the spiral groove is formed, and a torsion hook which is opened and closed by axial movement of the sleeve with respect to the hook drive shaft is pivotally supported by the hook support shaft. A plurality of projections are formed on the binding machine body near the outer peripheral surface of the sleeve, and the forward rotation stopper and the reverse rotation stopper are engaged with the projections to prevent forward rotation and reverse rotation of the sleeve. A control device that controls the start and stop of the hook drive motor so as to rotate the hook drive shaft forward with a torque smaller than the static friction of the sleeve. It rotates forward with the hook drive shaft, and the projection engages with the forward rotation stopper to position the torsion hook at the initial angular position.
In the process of further forward rotation of the hook drive shaft, the sleeve is advanced by engagement of the projection and the forward rotation stopper, the torsion hook is closed in a direction to grasp the wire ring at the initial angular position, and the axial movement range of the sleeve is reduced. At the front end, the protrusion is removed from the forward rotation stopper, the sleeve and the hook drive shaft are integrally rotated forward, and when the hook drive shaft is reversed, the protrusion engages with the reverse rotation stopper to retract the sleeve to the standby position. A torsion hook operating mechanism, characterized in that: