JP2000263461A - Binding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a binding machine to always tightly fasten a wire against a target binding spot and besides reliably twist a wire loop even by one round. SOLUTION: A binding machine comprises a twist shaft mechanism 31 having two limit gates 65 held in a manner to be brought into pressure contact with each other in the wire-through groove 63c of a twist head 63 rotated by a twist motor 37; and loop forming guides 51 and 53 to run a wire (w) in a loop- form. The binding machine is further provided with a wire press rod 69 slidably supported on a main shaft 61 and at a twist head 63 in a direction in which a front end face 69a is positioned facing a contact point between the two limit gates; and a cam 71 to protrude frontward a wire press rod simultaneously with the starting of rotation of the twist shaft mechanism. A part of a loop wire is securely positioned by a wire press rod 69 and a limit gate 65 and a wire loop is twisted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binding machine, and more particularly, to a binding machine that automatically binds a wire by winding a wire around a desired binding location and twisting the wire. .

[0002]

2. Description of the Related Art For example, there is a rebar tying machine as a device for automatically tying rebars in rebar assembly in reinforced concrete work. There are various types of binding machines of this type, but hand-held binding machines are generally
A loop forming guide that runs the wire as a binding wire so as to surround the intended binding portion in a loop shape, and a part of the loop wire passed through the loop forming guide is twisted to twist the loop wire. With a twist head. The twist head is provided with a gate having a torque limiter function that opens when the twist of the wire reaches a limit and releases the twisted wire.

FIG. 8 shows an example 1 of a conventional reinforcing bar binding machine provided with such a twist head (only the main part is shown in the drawing). In the figure, reference numeral 3 denotes a twist head. The twist head 3 is rotated by a motor, and is positioned so as to protrude from a front end of a hand-held casing (not shown), and has a truncated conical front half with a radially cut middle portion. A through groove 5 is formed. A circular gate arrangement hole (not shown) is formed at a position near the end of the wall 7 on both sides opposed to each other with the wire passage groove 5 therebetween. Two limit balls 9 made of steel balls are separately provided in the gate arrangement hole. Are located. Behind the twist head 3, a gate presser 11 pressed forward by a spring (not shown) is provided.
The tip slopes of the two arms 11a of the gate presser 11 are 2
The two limit gates 9 are pressed to press the limit gates 9 together.

A pair of upper and lower loop forming guides 13 and 15 are mounted on the front end of the casing. The loop forming guides 13 and 15 are traveling route guiding means for forming a wire w sent by a wire supply means (not shown) into a loop shape.
Has a groove extending in an arc shape with an open lower surface, and the lower loop forming guide 15 has a groove extending in an arc shape with an open upper surface. Then, a passage 5a between the back surface of the wire passage groove 5 in the twist head 3 and the limit gate 9
The wire w supplied from below travels along a closed path of the passage 5a, the upper loop forming guide 13, the lower loop forming guide 15, and the passage 5a to form a loop.

[0005] Thus, the reinforcing bar binding machine 1 is placed so that the desired binding location p (the location where the reinforcing bars 17 and 19 intersect each other) is located inside the upper and lower loop forming guides 13 and 15, and is not shown. When the trigger lever is pulled, the wire w sent out for a certain period of time travels two or more rounds of the closed path to form a coil-shaped wire loop w ′, and then the twist head 3 rotates to turn the wire loop w ′.
′ Is cut from the other parts, and the wire loop w ′ is twisted. In other words, the wire loop w 'is twisted by the wall 7 of the twist head 3 rotating while pressing both sides of the rear top portion of the wire loop w'. Then, the binding points p are tightened by the twisted wire loop w 'and bound together, and when the twist of the wire loop w' reaches the limit, the passage 5a of the wire loop w '
Is pushed out of the limit gate 9 and goes out of the passage 5a.

[0006]

In the rebar tying machine 1, the twisting of the wire loop w 'may often be completed while the wires are not tightly tightened to the rebars 17 and 19. That is, when the wire loop w ′ is being twisted, the twisting starts from the binding point p, or even after starting from the limit gate 9 side, the wire loop w ′ is formed after the twist reaches the binding point p firmly. If the wire deviates from the limit gate 9, the wire w is tightly tightened to the rebars 17 and 19, but in reality, the wire loop w ′ may come out of the limit gate 9 in a state other than these. .

It is thought that there are several causes. One of the causes is that the portion of the wire loop w 'to which the twisting torque is directly applied by the twist head 3 is not fixed to the twist head 3. Therefore, it is considered that this torque escapes from the limit gate 9 to the near side, and the twisting is advanced on the limit gate 9 side before it is sufficiently transmitted to the binding portion p side.
Further, in a portion where the wire loop w 'is caught in a long span for its diameter, such as a crossing point of the reinforcing bars 17 and 19, the shape retaining force and the rigidity are stronger than those of the other portions. It is also considered that the force that resists the twisting of the wool greatly acts, and the progress of the twisting is delayed by that much.

Therefore, the pressing force of the gate presser 11 against the limit gate 9 is increased (the force of the spring is increased), and the pressing force between the limit gates 9 is set high, so that the wire loop w 'is twisted. Although it is conceivable that the limit gate 9 is not easily opened, another problem arises in that the wire is easily cut or a large force is required to support the binding machine 1.

At the same time as the twist head 3 starts rotating, the binding machine 1 is pulled toward the user and the wire loop w 'is brought into close contact with the binding point p and the limit gate 9, respectively. Although the probability that the tightening is performed firmly seems to be somewhat increased, considerable skill is required to be able to perform such a delicate operation, and there is no guarantee that even if the skill is achieved, the sweetness of the tightening will not be ensured. In addition, if the pulling force of the binding machine 1 is mistaken, the wire loop w 'is ultimately insufficiently tightened.
Will fall off the limit gate 9,
It is not a fundamental solution.

[0010] Further, in the conventional reinforcing bar binding machine 1, there is also a problem that the wire loop w 'cannot be twisted by only one round. That is, since the wire loop w 'whose both ends are not clamped is a pseudo loop, that is, a coil, and is not an endless loop, if it is a loop of one round, both ends or One end is passage 5a
This is because the loop breaks out of the loop and twisting torque is not applied. For this reason, in order to be able to twist the wire loop w ′ reliably, it is necessary to form at least two loops, and only one loop of the wire loop is required as the binding strength. Even in such a case, it was necessary to form and twist a loop of two or more turns, which resulted in wasted material.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and it is possible to always tightly tighten a wire at a target tying portion, and moreover, even if the wire loop makes one round, the wire can be securely tightened. An object is to provide a binding machine that can be twisted.

[0012]

In order to achieve this object, a binding machine according to the present invention comprises a twist head having a wire passage groove which is rotated by a driving means and extends in a direction substantially perpendicular to a rotation center axis thereof; Two limit gates held by a twist head so as to be in contact with each other in a wire passage groove, gate pressing means for pressing the two limit gates against each other by a resilient force, and a target binding portion is surrounded by a loop. And a wire supply means for supplying a wire to the loop forming guide through a space after the limit gate of the wire passage groove, and the wire formed a loop on the loop forming guide. By rotating the twist head from the state, the loop-shaped wire is twisted and the desired binding point is A binding machine for bundling and, when the twist reaches a limit, the twisted wire pushes the limit gate open and comes off from the limit gate, the front end face facing the contact point between the two limit gates. A wire holding member slidably supported by the twist head in a direction, and a wire holding member moving means for projecting the wire holding member forward almost simultaneously with the start of rotation of the twist head.

According to the present invention, the portion of the loop-shaped wire corresponding to the contact point between the two limit gates is connected to the limit gate by the wire pressing member almost simultaneously with the start of rotation of the twist head. The wire is crimped and held, and in this state, the wire is twisted. Therefore, the torque of the twist head twisting the wire does not escape from the limit gate to the rear, and the shape holding force and rigidity are increased at a certain span portion including the position fixed to the limit gate, and the twist is performed. Therefore, the twisting torque can be sufficiently transmitted toward the target binding portion.
In addition, according to the present invention, since the mutually aligned portions in the wire loop are fixed in position by the wire pressing member and the limit gate, this loop is a pseudo but mechanically endless loop, Therefore, even if the loop is one round, the twist can be surely performed.

According to a second aspect of the present invention, in the binding machine according to the first aspect, between the wire pressing member and the wire pressing member moving means, a resilient member which constantly urges these to the front and rear opposite sides is inserted. It is a thing. Therefore, according to the present invention, the projecting distance of the wire pressing member, that is, the moving distance until the wire pressing member collides with the loop-shaped wire is self-adjusted according to the thickness of the wire to be used or the like, so that the thickness differs. There is no hindrance when using wires.

According to a third aspect of the present invention, in the binding machine according to the first or second aspect, the wire pressing member moving means is a cam, and the cam rotates integrally with the twist head and moves in the front-rear direction. The rotating cam element is configured by a rotating cam element that moves integrally with the member, and a fixed cam element whose position in the front-rear direction is fixed. When the twist head rotates, the rotating cam element is pressed forward by the fixed cam element. It is made to be done. If you do this,
Since the rotating cam element inevitably protrudes the wire pressing member forward with the rotation of the twist head, a special driving means for protruding the wire pressing member is not required, and accordingly, the configuration is reduced in size and cost. Can be
Moreover, there is no room for deviation in the timing at which the wire pressing member protrudes, so that the reliability of operation can be improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rebar tying machine 21 according to an embodiment of the present invention will be described below with reference to the drawings. Reference numeral 23 denotes a casing (a lower end portion is omitted in the drawing) of the reinforcing bar binding machine 21, and the casing 23 has a substantially pistol-like outer shape as shown in FIG. Casing 23
Is a casing main part 25 which is long in the front-rear direction and constitutes an upper part thereof; a grip 27 extending downward from an intermediate part in the front-rear direction of the casing main part 25; a lower front end of the casing main part 25; And a wire supply path 29 extending to the front end. Casing 2
3 is formed in two in the left-right direction.

The internal space of the casing main part 25 is divided into upper and lower parts, and a twist shaft mechanism 31 which is long in the front-rear direction is housed in an upper half area thereof, and a wire near the front end thereof is provided in a lower half area. A supply motor 33 has a control panel 35 (shown as a black box in the drawing) at the rear end,
A twist motor 37 as a driving means is disposed between the control panel 35 and the wire supply motor 33. A front opening 39 for exposing a front end of the twist shaft mechanism 31 is formed on a front wall of the upper half area, and a rear end of the upper half area has a circular cross-section cam. It is an arrangement hole 41,
A guide ball storage hole 43 is formed in a wall portion above the cam arrangement hole 41 so as to penetrate the wall vertically in the wall portion.

Reference numeral 45 denotes a feed roller (FIG. 1, FIG. 2,
This feed roller 45 is for feeding the wire w to a loop forming guide described later. The feed rollers 45 are meshed with each other and have two right and left sides, one of which is fixed to the output shaft of the wire supply motor 33. A small-diameter wire passage hole 4 penetrating vertically through a portion of the wall of the casing main portion 25 facing the position where the two feed rollers 45 contact each other from above.
7 are formed.

In a wire supply path 29 of the casing 23, a supply guide 49 (FIGS.
Reference). One end of the supply guide 49 protrudes out of a lower end (not shown) of the grip 27, and the other end is open at a position where the two feed rollers 45 contact each other from below. A wire w drawn from a wire roll (not shown) is introduced into the supply guide 49, and the leading end of the wire w is connected to two feed rollers 4.
Passed between five. Therefore, the wire supply motor 33
Is driven, the wire w is sent upward and is passed through the wire passing hole 47.

A pair of upper and lower loop forming guides 51 and 53 are mounted on the front end surface of the casing main portion 25. The loop forming guides 51 and 53 are opposed to each other with a vertical interval therebetween. The upper loop forming guide 51 is the front opening 3
9 has a groove 51a extending in an arc shape with its lower surface opened and projecting forward from above, and the lower loop forming guide 53 is located so as to project forward from under the front opening 39. An arc-shaped groove 5 having an open top surface
3a. The wire passage hole 47 is located immediately after the lower loop forming guide 53.

The wire w coming out of the wire passing hole 47 is guided by the groove 51a of the upper loop forming guide 51 to have an arc-shaped bending habit, and is formed by the groove of the lower loop forming guide 53. 53a, and again enters the groove 51a of the upper loop forming guide 51 to form a loop. In the rebar tying machine 21, the driving amount of the wire supply motor 33 is set so that a loop is formed around one turn.

The twist shaft mechanism 31 includes a main shaft 61, a twist head 63, two limit gates 65, a gate presser 67 for pressing the two limit gates 65 in a direction to close each other, and a shaft center of the main shaft 61. And a cam 71 for moving the wire pressing rod 69 forward.

The main shaft 61 has a long cylindrical shape in the front-rear direction, and a flat gear-like driven gear 73 is integrally formed at the rear end thereof. 73a are formed. This spring arrangement hole 73a
Is continuous with the shaft hole 61a of the main shaft 61. The part of the main shaft 61 deviated to the front end side and the part near the driven gear 73 are connected to the ball bearing 7 fixed to the casing 23.
5 rotatably supported. The spring arrangement hole 73a of the driven gear 73 is located so as to face the cam arrangement hole 41 of the casing main part 25 from the front side. A drive gear 77 is attached to the output shaft of the twist motor 37.
7 meshes with the driven gear 73. Therefore, the main shaft 61 is rotated as the twist motor 37 is driven.

The twist head 63 has a substantially shell shape. That is, as can be seen from FIG.
The third half 63a has a cylindrical shape with a short axial length, the first half basically has a truncated cone shape, and a middle portion in the radial direction is cut off to form a wide wire passage groove 63c.
And walls 63b on both sides thereof. A circular gate arrangement hole 6 is formed at a position near the tip of the wall 63b on both sides.
3d is formed, and of the outer peripheral surface of the rear half 63a,
An engagement groove 63e extending in the axial direction is formed in a portion corresponding to each of the gate arrangement holes 63d, and a front end of the engagement groove 63e reaches the gate arrangement hole 63d. A rod through hole 63f having a circular cross section is formed in the axis of the rear half 63a.
The front end of the rod passage hole 63f is formed by a wire passage groove 63c.
It is open to the back.

The limit gate 65 is made of a steel ball. As shown in FIG. 4, almost half of the limit gate 65 is accommodated in each of the two gate arrangement holes 63d of the twist head 63 with a required clearance. Wire passage groove 63c
And are provided so as to contact each other. The state in which the limit gate 65 is provided in this manner is elastically held by the gate presser 67.

The gate presser 67 includes a twist head 63
A ring-shaped base portion 67a having an outer diameter substantially equal to the outer diameter of the rear half portion 63a of the rear portion 63a, and two pressing arms 67 protruding forward from portions opposite to each other on the front surface of the base portion 67a.
b. The distal ends of the pressing arms 67b are formed so as to form wedges, and the opposing slopes of the wedge-shaped portions of the pressing arms 67b serve as pressing slopes 67c (see FIGS. 3 and 4) for pressing the limit gate 65. .

The spring receiving seat 79, the coil spring 81, and the base 67a of the gate presser 67 are externally fitted to the front portion of the main shaft 61 from the front ball bearing 75 in this order. And the twist head 6
3 is a state in which the two pressing arms 67b of the gate pressing element 67 are slidably fitted in the engaging grooves 63e, and the distal end of the main shaft 61 is inserted into the large diameter rear portion of the rod through hole 63f. The front half (the wall 63b and the wire passage groove 63c) is fixed to the main shaft 61 by fixing means (not shown), and protrudes from the front opening 39 of the casing 23. When the twist head 63 is attached to the main shaft 61, the coil spring 81 is compressed between the base 67 a of the gate presser 67 and the spring receiving seat 79.

The twist head 63 and the gate presser 67 are attached to the main shaft 61 so as to rotate integrally with the main shaft 61, and the gate presser 67 is always directed forward by the elastic force of the coil spring 81. Pressed. Thus, the pressing slope 67 of the gate pressing element 67
c presses the limit gates 65 so as to press against each other.

The wire holding rod 69 is formed in a thin cylindrical shape, and its front end surface 69a is machined into a spherical shape. A small pin driving hole 69b (see FIG. 3) penetrating in a direction perpendicular to the axial direction is formed at the rear end of the wire holding rod 69, and a key 83 is attached at a position relatively close to the pin driving hole 69b.

The cam 71 includes a rotating body 87 and a guide ball 89
And a guide ball pressing spring 91 composed of a coil spring. The rotating body 87 has a cylindrical shape having a shorter axial length than its diameter, and its rear half is thicker than its front half, and a cam groove 93 is formed in the middle part of the outer peripheral surface of this rear half. The cam groove 93 extends in the direction around the axis of the rotating body 87, and has a semicircular cross section, and a part of the standby part 9 which is wider toward the front side than the other part is widened.
3a. In the front half of the rotating body 87, a coupling hole 87a having a circular cross section is formed at the axis thereof.
A long hole 87b extending in the front-rear direction is formed through the coupling hole 87a in a direction perpendicular to the axial direction.

The rear end of the wire holding rod 69 is inserted into the coupling hole 87a of the rotating body 87 and the rotating body 87
The pin 95 passed through the long hole 87b is inserted into the pin driving hole 69b.
Is driven into. A small coil spring 97 is provided in a compressed state between the inner surface of the coupling hole 87a and the rear end surface of the wire holding rod 69. Thereby, the wire holding rod 69
And the rotating body 87 are coupled so as to rotate integrally with each other and move integrally in the axial direction.
7 are pressed in opposite directions. Therefore, when the wire pressing rod 69 is pressed relatively rearward, the pin 95 is retracted with respect to the rotating body 87 against the elastic force of the coil spring 97 within a range in which the pin 95 can move within the elongated hole 87b. I do.

The wire holding rod 69 and the rotating body 87 thus combined are provided so as to rotate integrally with the main shaft 61. That is, the wire holding rod 69 is
The main shaft 61 is slidably inserted into the shaft hole 61 a and the rod through hole 63 f of the twist head 63, and the key 83 is engaged with a key groove 61 b formed in the shaft hole 61 a of the main shaft 61. The rotating body 87 is rotatably housed in the cam arrangement hole 41 of the casing 23. Wire holding rod 69
Is held on the main shaft 61 in this manner, so that its front end face 6
9a opposes the contact point between the two limit gates 65 from behind.

A return spring 99 composed of a coil spring is provided in a compressed state between the back surface of the driven gear 73 and the front end surface of the rotating body 87.
The rotating body 87 and the wire holding rod 69 are constantly pressed backward. Then, the guide ball 8 constituting the cam 71
9 is housed in the guide ball housing hole 43, and a half portion thereof fits in the cam groove 93 of the rotating body 87, and the guide ball 89 is pressed against the cam groove 93 by the guide ball pressing spring 91.

Therefore, since the position of the guide ball 89 in the front-back direction is fixed, the position of the rotating body 87 and the wire pressing rod 69 in the front-back direction is defined by the engagement position of the guide ball 89 with the cam groove 93. You. That is, the rotating body 87 and the wire pressing rod 69 are held at the most retracted standby position when the guide ball 89 is accommodated in the standby portion 93a of the cam groove 93 as shown in FIG. 1, and as shown in FIG. In the state where the guide ball 89 is settled in a portion other than the standby portion 93a of the cam groove 93, the guide ball 89 is held at the forward position displaced forward from the standby position.

When the wire holding rod 69 is in the retracted position, its front end surface 69a is
Is located substantially in the same plane as the inner surface of the wire passage groove 63c, and has a certain space between the limit gate 65 and at least a space large enough to allow the wire w to pass through without difficulty.

The twist motor 37 and the wire supply motor 33 are connected to the circuit of the control panel 35. Also,
The switch lever 10 is attached to the grip 27 of the casing 23.
1, a battery (not shown) is connected to the circuit of the control panel 35 by pulling the switch lever 101, whereby the wire supply motor 33 rotates for a predetermined time to send out the wire w, and then the twist motor 37 is rotated by a predetermined amount. Twist motor 37
The rotation amount of the motor 37 is counted and controlled by, for example, a rotary encoder.
The control is performed such that the standby portion 93 a of the cam groove 93 is performed at a position corresponding to the guide ball 89. Therefore, when the twist motor 37 is stopped, the wire holding rod 69 is always at the retracted position. The reinforcing bar binding machine 21 is configured as described above.

Next, the method of use and operation of the reinforcing bar binding machine 21 will be described. For example, when it is desired to bind an intersection point p ′ (a target binding point) between the rebars 17 and 19 intersecting with each other, the upper and lower loop forming guides 13 and 15 are turned on with the power switch (not shown) turned on. As shown in the figure, the intersection point p 'is placed inside these,
Pull the switch lever 101. Then, the wire supply motor 33 is driven and the wire w is fed out by a predetermined length. As shown in the drawing, the fed wire w is connected to the back surface of the wire passage groove 63 c of the twist head 63 and the limit gate 65. Through the upper and lower loop forming guides 51 and 53 to form a wire loop w 'of about one turn. Therefore, this wire loop w
A part of 'is located in a row adjacent to the contact point between the two limit gates 65 from behind.

When the wire supply motor 33 is stopped and the feeding of the wire w is completed, the twist motor 37 is driven to rotate the twist shaft mechanism 31, and the wire pressing rod 69 moves forward simultaneously with the start of the rotation. That is, when the twist shaft mechanism 31 starts rotating, the rotating body 87 naturally starts rotating integrally with the twist shaft mechanism 31. At this time, the standby portion 93a of the cam groove 93 is relatively directed forward by the guide ball 89. This is because the rotating body 87 moves forward against the elastic force of the return spring 99. Accordingly, the front end of the wire holding rod 69 protrudes from the twist head 63.

When the wire holding rod 69 protrudes from the twist head 63, its front end surface 69a collides with a portion of the wire loop w 'which is arranged in two lines and is close to the limit gate 65, as shown in FIG. Then, this is pressed against the limit gate 65 to fix the position. Immediately after this, the wire w is cut by the edge of the wall 63b of the twist head 63 and the edge of the lower loop forming guide 53, and the wire loop w 'is cut off from other portions.
Thus, the rotation of the twist shaft mechanism 31 is started,
This rotation causes the wire loop w 'to be twisted,
Finally, as shown in FIG. 7, the intersections p 'of the reinforcing bars 17, 19 are tightened to bind the reinforcing bars 17, 19 to each other.

While this twisting is being performed, the two portions of the wire loop w 'are fixed to the twist head 63 by the limit gate 65 and the wire holding rod 69. Therefore, the torque at which the wall 63b of the twist head 63 twists the wire loop w 'is limited by the limit gate 65.
The shape does not escape backward, and the shape holding force and rigidity are increased in the part of a certain span including the position fixed to the limit gate 65, and the force against twisting works greatly. Set the torque to the desired binding point p
I can tell you enough. Thereby, the target binding part p 'is firmly tightened.

Since the portions of the wire loop w 'that are arranged in two lines are fixed to the limit gate 65, the wire loop w' is a pseudo-mechanically endless loop. Therefore, even if the wire loop w 'is one turn, this can be surely twisted.

As the twisting of the wire loop w 'proceeds, a ring surrounding the contact point between the limit gates 65 is formed. This wheel gradually gets smaller, and when it reaches its limit, two limit gates 65
To open the gate (the gate presser 67 moves the coil spring 8
(Retreats against 1 rebound). And
When the twist motor 37 rotates a predetermined number of times, it stops at a fixed position, and at the same time, the standby portion 93a of the cam groove 93 of the rotating body 87 faces the guide ball 89, so that the rotating body 87 and the wire pressing rod 69 return. The spring 99 returns to the standby position.

When the wire pressing rod 69 collides with the wire loop w ', it slightly retracts with respect to the rotating body 87 while compressing the coil spring 97 according to the thickness of the wire w (see FIG. 6). . The operation of the reinforcing bar binding machine 21 is performed as described above.

Although the embodiment of the present invention has been described in detail above, the specific configuration is not limited to this embodiment, and there is a change in design without departing from the gist of the present invention. Are also included in the present invention. For example, in the embodiment, as the moving means for advancing the wire pressing member, a cam using the rotating force of the twist head is used, but this means is not limited to the cam, and is driven by a solenoid, for example. Alternatively, an actuator or the like may be used. Further, the limit gate in the present invention is not limited to a spherical one, and may be a pin-like one that abuts each other in the axial direction. In the embodiment, the present invention is applied to the reinforcing bar binding machine, but the present invention is not limited to such a type of binding machine,
The present invention can be widely applied to various binding machines that bind by winding a wire loop on a target binding portion and twisting the wire loop.

[0045]

As described above, in the binding machine according to the present invention, the twisting head does not allow the twisting torque of the wire to escape from the limit gate to the rear, and furthermore, the position fixed to the limit gate is fixed. In a part of the span including a certain extent, the shape holding force and the rigidity are increased, and the force against twisting works great, so that the twisting torque can be sufficiently transmitted to the target binding portion. In addition, according to the present invention, since the mutually aligned portions in the wire loop are fixed in position by the wire pressing member and the limit gate, this loop is a pseudo but mechanically endless loop, Therefore, even if the loop is one round, the twist can be surely performed.

According to the second aspect of the present invention, the projecting distance of the wire pressing member, that is, the moving distance until the wire pressing member collides with the loop-shaped wire is self-adjusted according to the thickness of the wire to be used. There is no problem when wires having different thicknesses are used.

According to the third aspect of the present invention, the rotation side cam element inevitably protrudes the wire pressing member forward with the rotation of the twist head, so that a special driving means for protruding the wire pressing member is unnecessary. As a result, the size and the cost can be reduced accordingly, and there is no room for deviation in the timing at which the wire pressing member protrudes, so that the operation reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a side view showing a main part of a reinforcing bar binding machine according to an embodiment of the present invention, with a casing partially cut away.

FIG. 2 is an enlarged perspective view of a main part of the rebar tying machine of FIG. 1;

FIG. 3 is an exploded perspective view of a main part of the rebar tying machine of FIG. 1;

FIG. 4 is an enlarged horizontal sectional view of a front end of the reinforcing bar binding machine of FIG. 1;

FIG. 5 is a longitudinal sectional side view showing a state where a wire loop is formed with the rebar inside, in the rebar tying machine of FIG. 1;

FIG. 6 is a vertical sectional side view of a main part showing a state in which a wire holding rod has advanced in the rebar tying machine of FIG. 1;

FIG. 7 is a longitudinal sectional side view of a main part showing a state in which binding of reinforcing bars has been completed in the reinforcing bar binding machine of FIG. 1;

FIG. 8 is a schematic perspective view for explaining a binding operation by a conventional reinforcing bar binding machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Bundling machine 33, 45 Wire supply means 37 Twist motor 51 Loop formation guide 53 Loop formation guide 63 Twist head 63c Wire passage groove 65 Limit gate 67, 81 Gate pressing means 69 Wire pressing member 69a Front end face 71 (of wire pressing member) 71 Wire holding member moving means (cam) 87 Rotation side cam element 89 Fixed side cam element 97 Resilient member w Wire w 'Loop wire

Claims (3)

[Claims] 1. A twist head having a wire passage groove which is rotated by a driving means and extends in a direction perpendicular to a rotation center axis thereof, and two twist heads held by the twist head so as to contact each other in the wire passage groove. A limit gate, a gate pressing means for pressing the two limit gates against each other by a resilient force, a loop forming guide for running a wire so as to surround a target binding portion in a loop, and a limit gate of the wire passage groove. Wire supplying means for supplying a wire to the loop forming guide through the space after, the loop-shaped wire is twisted by rotating the twist head from a state where the wire has formed a loop on the loop forming guide When the desired bundling point is bound and the twist reaches the limit, the twisted wire is A wire holding member slidably supported by a twist head in a direction in which a front end face faces a contact between two limit gates, and A bundling member moving means for protruding the wire pressing member forward substantially simultaneously with the start of rotation of the head. 2. A binding machine according to claim 1, wherein a resilient member for constantly urging the wire holding member and the wire holding member to the front and rear sides is interposed between the wire holding member and the wire holding member moving means. Tying machine. 3. The binding machine according to claim 1, wherein the wire pressing member moving means is a cam, and the cam rotates integrally with the twist head and integrally with the wire pressing member in the front-rear direction. The rotating cam element is constituted by a moving rotating cam element and a fixed cam element whose position in the front-rear direction is fixed, and the rotating cam element is pressed forward by the fixed cam element when the twist head rotates. A binding machine characterized by the following.