JP3370420B2 - Metal strand bending method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for bending a metal strand such as a stainless wire, and more particularly to a metal strand bending method and a method suitable for manufacturing a treatment tool used for an endoscope. Regarding the device.

[0002]

2. Description of the Related Art A treatment tool as shown in FIG. 9 is attached to the tip of an endoscope. In the figure, (a) is called an elliptical treatment tool and (b) is called a half-moon treatment tool.
Each of them is manufactured by bending the metal wire 1 into a loop shape, and is used for advancing and retreating from the distal end portion of the endoscope by a doctor's operation to excise a polyp or a lesion. .

Conventionally, such a treatment tool is manufactured by manually bending a stranded metal wire as shown in FIG.
That is, the tweezers P, which holds the twisted wire 1 at a desired bending point, is rotated by θ in the direction of arrow A to form the bent portion (a in the figure), and the twisted wire 1 is lengthened as shown by arrow B. The arcuate curved portion is formed by squeezing in the direction (b in the same figure), and this operation is repeated to manufacture the treatment tool.

However, in general, the treatment tool has to be finished into a two-dimensional shape, that is, a shape that can be accommodated within a plane, so that the molding operation is not easy. Because, Figure 10
This is because, in the case of a three-dimensional treatment tool in which “raising” has occurred in the vertical direction as shown in (c), the loop-shaped gripping portion moves up and down as it moves forward and backward, which prevents accurate operation. It is difficult to automate bending a twisted material such as a stranded metal wire into an accurate two-dimensional shape, it is difficult to automate, and it is inefficient and inefficient as well as individual differences. It was big and the improvement was desired.

By the way, as an apparatus for automatically bending a metal wire, there is known an apparatus disclosed in Japanese Patent Laid-Open No. 62-179840. As shown in FIG. 11, this device performs bending work by pressing the wire W guided by the receiving member G from the side with the pressing pin P, and alternates with this work, the wire W is pushed by the pushing means S. It is sent out and shaped into a predetermined arc shape. In other words, in this device, the bending process is performed by assuming that the arc is a continuation of short strings.

[0006]

However, when a treatment tool for an endoscope is manufactured by using the above-mentioned conventional apparatus, it looks macroscopically a smooth arc shape but is microscopically angular. Since the strings are formed continuously, there was a problem that they could not be put to practical use due to the squeaking and the catching that was felt during the operation. Moreover, in the above-mentioned conventional device, since the wire is only pressed from the side and bent, it is unavoidable that the above-mentioned "raising" occurs as the bending work progresses. At such a bent portion, "raising" occurs in the twisting direction of the twisted wire, and a final correction work by an expert is indispensable.

The present invention has been made in view of the above-mentioned problems, and enables smooth bending which has conventionally been forced to be done by hand, and has a high-quality two-dimensional shape without "raising". It is an object of the present invention to provide a metal twisted wire bending method capable of easily performing working, and to provide a metal twisted wire bending apparatus capable of automatically performing such bending work.

[0008]

The present inventors have found that the cross-sectional structure of a strand changes before and after bending as follows. That is, the stranded wire before bending is shown in FIG.
As shown in (a) and (b), the single-wire bundles 1a, 1a, ... Are arranged in a concentric circle and radially uniformly. On the other hand, when the stranded wire is bent, the same figure (c)
As shown in Fig. 4, since a path difference is generated between the inner circumference BC and the outer circumference DE, the inner circumference BC is displaced outward and the outer circumference DE is displaced inward so that the entire cross-sectional shape becomes an ellipse. It is deformed ((d) in the figure).

Considering this with respect to the cross-sectional shape of the stranded wire, it means that the spiral coil shape which is a perfect circle before bending is plastically deformed into an elliptical spiral coil after bending. . In this way, the bent strand changes from a circular structure to an elliptical structure.
Then, the twisted wire once rearranged in the elliptical cross-sectional structure has a bending tendency, so that it cannot be easily returned to the original straight line.

From the above, it is understood that when bending a stranded wire, it is preferable not only to simply bend it, but also to crush it so that its cross section becomes an ellipse while being held in the bent state. Then, at this time, applying a tensile force is convenient because it helps to form an ellipse and can prevent undulations from occurring in the twisted wire. Moreover, according to such a processing method, the "wake-up" which has been a problem in the past does not occur.

Therefore, in the method for bending a metal strand according to the present invention according to claim 1, a metal strand is wound around the outer periphery of the mold to apply a tensile force to the strand, while the outer peripheral surface of the mold is roughly formed. Pressing the stranded wire with a pressing member from the line direction, gradually moving the pressing portion in the length direction of the stranded wire, and bending the stranded wire into the same shape as the outer periphery of the mold. did.

According to a second aspect of the present invention, there is provided a twisted wire bending apparatus of the present invention, which has a mold having an outer peripheral shape that matches a desired bent shape of the metal twisted wire, and a stranded wire wound around the outer circumference of the mold. It is composed of a tension applying means for applying a force and a pressing member for pressing the twisted wire from the outer peripheral side of the mold.

In this case, a pressing position moving means for moving the die and the pressing member relative to each other is provided, and the pressing location moving means sets the pressing direction of the pressing member to the pressing direction of the die. It is preferable to control so as to match the normal direction of the outer peripheral surface.

[0014]

In the method and apparatus for bending a metal strand according to the present invention,
While twisting a metal strand around the outer periphery of the mold and holding it in a desired bending shape, by pressing this, each single wire forming the strand is plastically deformed into an elliptical spiral to perform bending work.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description.

[0016]

First Embodiment First, a first embodiment of the present invention will be described. Figure 1
[Fig. 3] is a plan view (a) and a front view (b) showing a metal strand bending device. As shown in the figure, in this device, a metal strand 1 is wound around the outer periphery of a mold 2, and both ends of the strand 1 are pulled by the tension applying means 3, while the strand 1 is pulled from a substantially normal direction of the outer peripheral surface of the mold 2. While pressing with the pressing member 4, the pressing portion is gradually moved in the length direction of the stranded wire 1 to bend the stranded wire 1 into the same shape as the outer periphery of the mold 2.

The mold 2 is formed in an outer peripheral shape that matches a treatment tool for an endoscope, and is fixed to the upper surface of a rotary table 51 via a pedestal 52 for height adjustment. Further, the tension applying means 3 is also attached to the turntable 51 via the pedestal 52a.

As shown in FIG. 2, the tension applying means 3 includes a chuck 31 for gripping both ends of the stranded wire 1, and a chuck 31 for holding the stranded wire 1.
The guide 32 is movably guided in the longitudinal direction, and the air cylinder 33 applies a rightward force in the drawing to the chuck 31, and the pulling force of the air cylinder 33 is controlled by a predetermined program. This tensile force is
In addition to being determined according to the conditions such as the thickness of the stranded wire 1, the type 2
It is also finely controlled according to which part of the bending process is being performed, that is, the current curvature of the bending part.

As a simpler tensioning means 3, as shown in FIG. 3 (a), a string 35 having a weight 34 hung is tied to the side surface of the chuck 31 via a pulley 36, or as shown in FIG. 3 (b). As shown, the pedestal 37 to which the chuck 31 is attached may be driven by a ball screw 38 and a motor 39 to apply a tensile force.

In the pressing member 4, the head 41 at the tip is formed into a concave surface having a curvature R or V shape as shown in FIG. 4, so that the line does not escape due to the pressing force, and the rod of the air cylinder 42. It is attached to the tip. The air cylinder 42 is attached to the base 6 via a moving stage 53 and is movable in the Y direction.

That is, in this embodiment, the pressure table moving means 5 is provided with the rotary table 51 and the moving stage 53, and the die 2 and the pressure member 4 are positioned relative to each other. Specifically, the direction of the pressing portion of the mold 2 is set by the rotary stage 51, and then the head 41 is moved by the moving stage 53.
By adjusting the position in the Y direction, the pressing direction can always be made to coincide with the normal line direction of the outer peripheral surface of the mold 2, and the control device (not shown) controls the pressing direction.

Next, the operation of the metal strand bending apparatus of the present embodiment having the above structure will be described with reference to FIG.

(1) The stranded wire 1 is horizontally wound around the outer peripheral side surface 2a of the mold 2 and held by the tension applying member 3 to apply a tensile force so as not to sag.

(2) First, the bent portion A is processed. As shown in FIGS. 2B and 2C, the rotary table 51 is rotated so that the flat surface eye of the mold 2 is parallel to the tip of the pressing member 4. Then, the moving stage 53 is moved to move the pressing member 4
Align the tip of the to the point a.

(3) The pressing member 4 is moved back and forth to press the stranded wire 1 once or several times to perform bending work. The same work is performed on the flat surface on the opposite side.

(4) Next, the curved portion B is processed. By combining the rotation of the rotary table 51 and the parallel movement of the moving stage 53, the pressing member 41 is pressed against the outer peripheral surface of the mold 2 in the direction of the normal line. Then, by combining the minute rotation of the rotary table 51 and the minute parallel movement of the moving stage 53, the pressing member 41 is arranged so as to always match with the normal line direction of the outer peripheral surface of the mold 2, and is moved from point D to point E. Pressing work is continued while moving the pressing point little by little.

(5) The other parts are also pressed in accordance with this.
Through the above work, it is possible to manufacture a treatment tool in which a bent portion and a curved portion are combined.

In the case of the treatment tool shown in FIG. 6, the overall work flow is the same. However, when the points A and A are pressed, the angle between the tip of the pressing member 41 and each point is θ.
The angle of the rotary table 51 is set so that = θ '.

According to this embodiment, as compared with the manual bending work relying on the intuition, the machine is processed under a certain condition (die, pressing member shape, pressing force, pressing interval, pressing speed, etc.). Therefore, there is no variation in accuracy and stable quality can be obtained.

[0030]

Second Embodiment Next, a second embodiment of the present invention will be described. Figure 7
[Fig. 3] is a plan view (a) showing a metal stranded wire device and a side view (b) from the left side of the device. In this embodiment, as shown in FIG. 7A, a movable stage 53 which is movable in the left-right direction is provided on the base 6, and a rotary table 51 is provided thereon. The rotary table 51 includes a pair of molds 2 with the center of the table 51 as an axis of symmetry.
2, 22 are erected, and the pressing members 4, 4 fixed to the support plate 43 are attached so as to face the respective molds 22, 22.

The pressing members 44 of the pair of molds 22, 22 are
The outer peripheral surface facing 44 corresponds to the curvature of the desired bending shape. In a direction perpendicular to the pair of molds 22 and 22 (vertical direction in the figure), as shown in FIG. 2B, the pair of molds is attached to the pair of bent support members 44 and 44, respectively.
There are a mold 21 and a mold 23 set at the same height as 2, 22. The base ends of the respective support members 44, 44 are fixed to the pedestal 6,
The tip thereof extends on the rotary table 51, and as shown in FIG. 7A, the mold 21 is bifurcated and has a curved surface that guides each end of the twisted wire at its inner peripheral surface. Is formed, and the outer peripheral surface of the mold 23 is formed in a bent shape of a twisted wire.

On the support member 44 of the mold 21, the tension applying means 3 similar to that of the first embodiment is arranged. Also, type 2
At the rear of 3, a pressing member 4 for pressing and pressing the twisted wire wound on the mold 23 and its supporting member are attached to the pedestal 6. The moving stage 53 and the rotary table 5
The drive device 1 is not shown.

Next, the operation of the metal strand bending apparatus of this embodiment having the above structure will be described. (1) One strand is made into a ring shape, and its tip end is locked to a bend-shaped die. Then, each wire end is placed along the die 22 and 22, and dropped into the two crotch portions of the die 21 to form a twisted wire. It is made horizontal and held by the tension applying means 3 to apply a tensile force.

(2) Due to the bending of the stranded wire,
The twisted wire is pressed against the die 23 by the pressing member 4 once or several times. After the pressing, the pressing member 4 and the mold 23 hold the stranded wire while sandwiching it.

(3) Next, the moving stage 51 is moved in one direction (for example, leftward). During this movement, the mold 2
Since 1 and 23 do not move, one end of the stranded wire is pulled by the mold 22 on the moved side, and the loop shape on the left side in FIG. 7A increases along the mold 22 on the left side until a desired curved shape is obtained. Be made bigger.

(4) Next, the twisting wire along the left mold 22 is pressed once or several times by the left pressing member 4. This pressing force causes the twisted wire circle to change into an elliptical structure. In addition, at the time of this pressure, the rotary table 51
The same portion of the stranded wire may be pressed several times without rotating, and the twisting wire is pressed while the rotary table 51 is finely rotated within a range facing the pressing member 4 on the molding surface of the mold 22. May be repeated.

(5) After the completion of molding with the left mold 22, the rotary table 51 is moved to the right by a predetermined amount, and the other end of the stranded wire is pulled by the right mold 22 to strike the right mold 22. The stranded wire of the portion is formed by the pressure member 4.

(6) After the above-mentioned molding, the rotary table 51 is returned to the initial position (the position shown in FIG. 7A), and the molded stranded wire is taken out.

According to this embodiment, by changing the mounting position (distance from the center of rotation) of the die 22 on the rotary table 51, it is possible to form curved portions having various curvatures.

The present invention is not limited to the above embodiment, but may be implemented as follows, for example. (1) A guide groove into which a twisted wire may be formed may be formed on the outer periphery of the mold. Strands can be set accurately and quickly.

(2) When a plurality of strands are wound in parallel with the vertical direction of the mold and processed at one time, the production efficiency can be improved.

(3) The tip of the pressing member may be formed according to the bending curvature and the bending angle of the outer periphery of the mold, and may be replaced according to the part to be molded. Since the male and female molds are suitable for pressing, it is possible to mold in a wide range with one pressing force.

(4) The pressing point moving means for moving the pressing point may be moved only by the pressing member, or may be moved only by the die, and various combinations of deformations are possible.

(5) That is, in the first embodiment, the rotation of the mold and the parallel movement of the pressure member are combined, but instead of this, an XY stage is mounted on the rotary table, and the mold and tension are applied thereto. The pressing member may be fixed toward the center of rotation while mounting the means. In this case, the XY stage can be adjusted so that the center of curvature of the mold coincides with the center of rotation, and the pressure table can be continuously pressed while slowly rotating the rotary table.

(6) When moving the pressing portion, the pressing member may be moved while being pressed to impart the ironing action. In this case, the tip of the pressing member may be a roller.

[0046]

As described above, according to the method and apparatus for bending a metal strand of the present invention, smooth bending can be performed, which has conventionally been forced to be done by hand.
Bending of a high-quality two-dimensional shape without "raising" can be performed easily and automatically.

[Brief description of drawings]

FIG. 1 is a plan view (a) and a front view (b) showing a metal strand bending apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a tension applying unit according to the first embodiment.

FIG. 3 is a diagram illustrating a modified example of a tension applying unit.

FIG. 4 is a diagram showing a shape of a tip end portion of a pressure member of Example 1.

FIG. 5 is a diagram for explaining the operation of the metal strand bending apparatus according to the first embodiment.

FIG. 6 is a view for explaining the operation of the metal strand bending apparatus of Example 1.

FIG. 7 is a plan view (a) and a side view (b) showing a metal strand bending apparatus according to a second embodiment of the present invention.

FIG. 8 is a view for explaining the operation of the metal twisted wire bending method of the present invention.

FIG. 9 is a plan view showing a treatment tool for an endoscope manufactured by applying the present invention.

FIG. 10 is a diagram illustrating a conventional method of bending a metal twisted wire by hand.

FIG. 11 is a plan view (a) and a main part enlarged view (b) illustrating a conventional metal wire bending apparatus.

[Explanation of symbols]

1 metal strand Type 2 3 Tension applying means 31 chuck 32 guidance 33 Air cylinder 4 Pressure member 41 heads 42 Air cylinder 5 Pressing point moving means 51 turntable 52 pedestal 53 Moving stage 6 bases

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-62-179840 (JP, A) JP-A-7-144242 (JP, A) JP-A-7-68335 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B21F 1/00 A61B 17/22 310

Claims (3)

(57) [Claims] 1. A metal strand is wound around the outer periphery of a mold to apply a tensile force to the strand, and the strand is pressed by a pressure member from a substantially normal direction of the outer peripheral surface of the mold. A method for bending a twisted wire according to claim 1, wherein the pressing portion is gradually moved in the length direction of the twisted wire to bend the twisted wire into the same shape as the outer circumference of the mold. 2. A mold having an outer peripheral shape matching a desired bent shape of a metal strand, a tension applying means for applying a tensile force to the twisted wire wound around the outer periphery of the mold, and an outer peripheral side of the mold. A twisted wire bending device comprising a pressing member for pressing the twisted wire. 3. The metal strand bending apparatus according to claim 2, further comprising a pressing portion moving means for relatively moving the die and the pressing member, and the pressing portion moving means for the pressing portion moving means. A metal twisted wire bending apparatus, wherein the pressing direction of the pressure member is controlled so as to match the normal direction of the outer peripheral surface of the mold.