Patent Description:
A conventional multi-core cable is known in the art that has a plurality of electric wires and a sheath covering those wires. For a multi-core cable, the process of making a cut in the tip portion of the sheath, and the process of pulling out the tip portion of the sheath to expose the tip portion of the electric wires are performed. Then, for example, the process of crimping a terminal onto the tip portion of the electric wire, etc., is performed. However, if kinks remain in the electric wires when the tip portion of the sheath is pulled out, the subsequent processes for the electric wires cannot be done desirably. In view of this, devices for correcting kinks in electric wires have been proposed in the art.

Utility Model Application Publication No. <CIT>discloses an electric wire untwisting device for simultaneously untwisting electric wires while pulling out the sheath. This electric wire untwisting device has a retention member for retaining a sheath-unpeeled portion of a multi-core cable and a gripping means for gripping the sheath to be peeled off. The gripping means includes an upper member and a lower member for gripping the sheath by clamping. When pulling out the sheath, the gripping means moves away from the retention member, and at the same time, the upper member and the lower member move in opposite directions to each other in the left-right direction. Thus, the sheath is pulled out while being rotated. A multi-core cable untwisting device according to the preamble of claim <NUM> is disclosed in <CIT>.

PTL <NUM>: Utility Model Application Publication No. <CIT>.

The total amount of rotation of the sheath can be set in advance according to the twist pitch of the electric wires twisted in the sheath. Where the strip length of the sheath is L [mm] and the total amount of rotation of the sheath is α [degrees], the sheath to be pulled out will be rotated by α [degrees] while the sheath moves by the distance L [mm] in the axial direction of the multi-core cable. If the sheath is pulled out at a constant speed and rotated at a constant rotational speed, the amount of rotation per unit travel distance of the sheath is α/L [degrees/mm].

However, as a result of a test by the present inventors, when the sheath is pulled out at a constant speed and rotated at a constant rotational speed, the twist in the electric wire may not be corrected sufficiently, such as when the sheath to be pulled out is long, for example.

The present invention has been made in view of this problem, and an object of the present invention is to provide a multi-core cable untwisting device for simultaneously pulling out a sheath while correcting kinks in electric wires, wherein the kinks can be corrected more desirably than with conventional techniques.

A multi-core cable untwisting device according to the present invention is a multi-core cable untwisting device for pulling out a tip portion of a sheath of a multi-core cable, which includes a plurality of electric wires and the sheath that covers the electric wires, while correcting kinks in the electric wires. The untwisting device includes: a retention member configured to retain a non-tip portion of the sheath that has a cut between the tip portion and the non-tip portion; a gripping member configured to grip the tip portion of the sheath; a pull-out device configured to pull out the tip portion of the sheath by moving at least one of the gripping member and the retention member so that the gripping member moves away from the retention member; a rotating device configured to relatively rotate the tip portion of the sheath that is gripped by the gripping member and the non-tip portion of the sheath; and a control device configured to control the pull-out device and the rotating device. The control device is configured to perform a first control and a second control from start until end of the pulling-out of the tip portion of the sheath, wherein the first control is to control the pull-out device and the rotating device so that the amount of rotation per unit travel distance of the tip portion of the sheath is smaller than a predetermined amount of rotation, and the second control is to control the pull-out device and the rotating device so that the amount of rotation per unit travel distance of the tip portion of the sheath is equal to or greater than the predetermined amount of rotation. Note that the phrase ". is smaller than a predetermined amount of rotation" includes cases where the amount of rotation is zero (in other words, no rotation).

With a multi-core cable, when pulling out the sheath, the electric wires are pulled by receiving a frictional force from the sheath. However, because of the kinks in the electric wires in the sheath, the electric wires come into close contact with each other as the electric wires are pulled. Where the electric wires are in close contact with each other, the kinks are not corrected sufficiently even by rotating the sheath in the opposite direction to the direction in which the electric wires are twisted if the amount of rotation per unit travel distance is relatively small.

With the untwisting device described above, however, the first control and the second control are performed from the start until the end of the pulling-out of the tip portion of the sheath. In the second control, the amount of rotation per unit travel distance of the tip portion of the sheath is relatively large. For example, where the strip length of the sheath is L [mm] and the total amount of rotation of the sheath is α [degrees], the amount of rotation per unit travel distance of the sheath in the second control is larger than α/L [degrees/mm]. Therefore, with the untwisting device described above, it is possible to correct kinks better than with conventional techniques. On the other hand, in the first control the amount of rotation per unit travel distance of the tip portion of the sheath is relatively small or zero. Therefore, the total amount of rotation of the tip portion of the sheath will not be too large from the start until the end of the pulling-out. Thus, it is possible to avoid excessively rotating the tip portion of the sheath, and the process will not create new kinks in the reverse direction in the electric wires.

In one preferred embodiment, the control device is configured to pull out the tip portion of the sheath without rotating the tip portion of the sheath in the first control, and to pull out the tip portion of the sheath while rotating the tip portion of the sheath in the second control.

With the embodiment described above, the tip portion of the sheath is not rotated in the first control, and the amount of rotation per unit travel distance of the tip portion of the sheath can be increased accordingly in the second control. Therefore, it is possible to avoid excessively rotating the tip portion of the sheath, and it is possible to desirably correct the kinks.

In one preferred embodiment, the control device is configured to perform the second control after the first control.

With the embodiment described above, it is possible to desirably pull out the tip portion of the sheath, and it is possible to desirably correct the kinks in the electric wires.

In one preferred embodiment, the control device is configured to repeat the first control and the second control for two iterations or more from start until end of the pulling-out of the tip portion of the sheath.

With the untwisting device described above, it is possible to desirably correct the kinks in the electric wires when performing the second control, and in this process, kinks can be corrected more effectively for portions of the electric wires that are closer to a portion of the sheath that is gripped by the gripping device. With the embodiment described above, the first control and the second control are performed repeatedly for two iterations or more. Therefore, the process of effectively correcting the kinks can be performed frequently. Thus, it is possible to more desirably correct the kinks.

In one preferred embodiment, a pull-out length of the first control is equal between different iterations and/or a pull-out length of the second control is equal between different iterations.

With the embodiment described above, the first control and/or the second control are simplified.

In one preferred embodiment, a total pull-out length of the tip portion of the sheath in an nth iteration (where n is a predetermined natural number) of the first control and the second control is shorter than a total pull-out length of the tip portion of the sheath in an mth iteration (where m is a predetermined natural number other than n) of the first control and the second control. The amount of rotation of the tip portion of the sheath in the nth iteration of the second control is smaller than the amount of rotation of the tip portion of the sheath in the mth iteration of the second control.

With the embodiment described above, the amount of rotation per unit travel distance of the tip portion of the sheath can be made relatively even between the nth iteration of the first control and the second control and the mth iteration of the first control and the second control. Thus, the kinks in the electric wires can be corrected relatively evenly between the nth iteration and the mth iteration of the first control and the second control.

In one preferred embodiment, αn/La = αn+<NUM>/Ln+<NUM> holds, where Ln is a total pull-out length of the tip portion of the sheath in an nth iteration (where n is a predetermined natural number) of the first control and the second control, αn is the amount of rotation of the tip portion of the sheath in the nth iteration of the second control, Ln+<NUM> is a total pull-out length of the tip portion of the sheath in an n+<NUM>th iteration of the first control and the second control, and αn+<NUM> is the amount of rotation of the tip portion of the sheath in the n+<NUM>th iteration of the second control.

With the embodiment described above, the amount of rotation per unit travel distance of the tip portion of the sheath is equal between the nth iteration of the first control and the second control and the n+<NUM>th iteration of the first control and the second control. Thus, the kinks in the electric wires can be corrected evenly between the nth iteration and the n+<NUM>th iteration of the first control and the second control.

In one preferred embodiment, the rotating device includes an actuator configured to rotate the gripping member.

With the embodiment described above, it is possible to stably rotate the tip portion of the sheath, and it is possible to stably perform at least the second control. Regardless of the amount of rotation of the tip portion of the sheath, the gripping member can be made smaller.

In one preferred embodiment, the control device is configured to pull out the tip portion of the sheath by <NUM> or more from the start until the end of the pulling-out of the tip portion of the sheath.

Typically, the longer the pull-out length of tip portion of the sheath, the more difficult it is to correct the kinds in the electric wires. With the embodiment described above, the effect of the present invention of correcting the kinks more desirably than with conventional techniques is more pronounced.

According to the present invention, there is provided a multi-core cable untwisting device for simultaneously pulling out a sheath while correcting kinks in electric wires, wherein the kinks can be corrected more desirably than with conventional techniques.

A multi-core cable untwisting device (hereinafter referred to simply as an "untwisting device") according to one embodiment of the present invention will be described with reference to the drawings. <FIG> is a perspective view of an untwisting device <NUM>, and <FIG> is a side view of the untwisting device <NUM>. <FIG> is a plan view of a multi-core cable <NUM>, and <FIG> is a plan view showing the inside of a tip portion of the multi-core cable <NUM>.

As shown in <FIG>, the multi-core cable <NUM> includes a plurality of covered electric wires <NUM>, one uncovered electric wire <NUM>, and a sheath <NUM> covering these wires <NUM>, <NUM>. Although not shown in the figures, the electric wire <NUM> includes a plurality of strands made of a conductor such as a metal. The electric wires <NUM> each include a plurality of strands made of a conductive material such as a metal, and a cover covering those strands that is made of an insulating material such as a synthetic resin. Hereafter, the covered electric wires <NUM> and the uncovered electric wire <NUM> are referred to as core wires and a drain wire, respectively. Here, the multi-core cable <NUM> includes four core wires <NUM>. Note however that there is no particular limitation on the number of core wires <NUM>. Also, there is no particular limitation on the number of drain wires <NUM>. While there is no particular limitation on the material of the sheath <NUM>, it may be chloroprene rubber, polyvinyl chloride, polyethylene, etc., for example.

As shown in <FIG>, the sheath <NUM> of the multi-core cable <NUM> to be processed by the untwisting device <NUM> has a cut (also called a slit) 5C in advance. By the cut 5C, the sheath <NUM> is severed into a tip portion (hereinafter referred to as the sheath tip portion) 5A and a non-tip portion 5B. As shown in <FIG>, the core wires <NUM> and the drain wire <NUM> are twisted in the sheath <NUM>. That is, the core wires <NUM> and the drain wire <NUM> in the sheath <NUM> extend in spiral and are kinked. The untwisting device <NUM> pulls out the sheath tip portion 5A while correcting the kinks in the core wires <NUM> and the drain wire <NUM> to be exposed.

As shown in <FIG>, the untwisting device <NUM> includes a retention device <NUM> for retaining the non-tip portion 5B of the sheath <NUM> of the multi-core cable <NUM>, a gripping device <NUM> for gripping the sheath tip portion 5A, a pull-out device <NUM> for pulling out the sheath tip portion 5A, and a rotating device <NUM> for rotating the sheath tip portion 5A. As shown in <FIG>, the untwisting device <NUM> includes a control device <NUM> for controlling the retention device <NUM>, the gripping device <NUM>, the pull-out device <NUM> and the rotating device <NUM>. In the following description, for the purpose of discussion, the tip portion 5A side of the sheath <NUM> (the right side of <FIG>) will be referred to as the front side and the non-tip portion 5B side (the left side of <FIG>) as the rear side. The sheath tip portion 5A is pulled out forward.

As shown in <FIG>, the retention device <NUM> includes a retention clamp <NUM> having a pair of left and right clamp jaws <NUM>, 11R, and an actuator <NUM> that drives the clamp jaws <NUM>, 11R toward and away from each other. While there is no particular limitation on the actuator <NUM>, the actuator <NUM> is herein an air cylinder. When the clamp jaws <NUM>, 11R are moved toward each other, the retention clamp <NUM> is closed. Then, the non-tip portion 5B of the sheath <NUM> is held by being clamped between the clamp jaws <NUM>, 11R. When the clamp jaws <NUM>, 11R are moved away from each other, the retention clamp <NUM> is opened. Then, the retention of the non-tip portion 5B of the sheath <NUM> is released.

The gripping device <NUM> includes a gripping clamp <NUM> and an actuator <NUM> that opens and closes the gripping clamp <NUM>.

<FIG> is a side view of the gripping clamp <NUM>, and <FIG> is a cross-sectional view of the gripping clamp <NUM>. <FIG> is a front view of the gripping clamp <NUM>. The gripping clamp <NUM> includes a first clamp jaw <NUM> and a second clamp jaw <NUM>. The first clamp jaw <NUM> and the second clamp jaw <NUM> oppose each other so that the sheath tip portion 5A can be gripped. Here, the first clamp jaw <NUM> includes a plurality of triangular plate members 21a arranged in the front-rear direction (see <FIG> and <FIG>). The second clamp jaw <NUM> includes a plurality of triangular plate members 22a arranged in the front-rear direction. The plate member 21a and the plate member 22a are arranged alternating with each other in the front-rear direction. Note that the configuration of the first clamp jaw <NUM> and the second clamp jaw <NUM> described herein is merely an example. There is no particular limitation on the configuration of the first clamp jaw <NUM> and the second clamp jaw <NUM> as long as the sheath tip portion 5A can be gripped.

When the first clamp jaw <NUM> and the second clamp jaw <NUM> are moved toward each other, the sheath tip portion 5A is clamped by the first clamp jaw <NUM> and the second clamp jaw <NUM>. As a result, the sheath tip portion 5A is gripped by the first clamp jaw <NUM> and the second clamp jaw <NUM>. When the first clamp jaw <NUM> and the second clamp jaw <NUM> are moved away from each other, the grip of the sheath tip portion 5A is released.

As shown in <FIG>, the gripping clamp <NUM> includes a link mechanism <NUM> that is linked to the first clamp jaw <NUM> and the second clamp jaw <NUM>, and a piston rod <NUM> linked to the link mechanism <NUM>. As shown in <FIG>, the piston rod <NUM> is linked to the actuator <NUM>. While there is no particular limitation on the actuator <NUM>, it is herein an air cylinder. The piston rod <NUM> is rotatably linked to the actuator <NUM>. As shown in <FIG>, when the actuator <NUM> moves the piston rod <NUM> forward (rightward in <FIG>), the first clamp jaw <NUM> and the second clamp jaw <NUM> move away from each other. That is, when the piston rod <NUM> is extended forward, the gripping clamp <NUM> is opened, thereby releasing the grip of the gripping clamp <NUM>. On the other hand, as shown in <FIG> and <FIG>, when the actuator <NUM> moves the piston rod <NUM> rearward, the first clamp jaw <NUM> and the second clamp jaw <NUM> move toward each other. That is, when the piston rod <NUM> contracts, the gripping clamp <NUM> is closed, and the gripping clamp <NUM> grips the sheath tip portion 5A. Note that the solid line in <FIG> represents the state in which the gripping clamp <NUM> is closed, and the two-dot-chain line represents the state in which the gripping clamp <NUM> is open. Thus, the gripping clamp <NUM> is opened and closed by the actuator <NUM>. Note that the piston rod <NUM> is not shown in <FIG>.

As shown in <FIG>, the rotating device <NUM> includes a support plate <NUM> that rotatably supports the gripping clamp <NUM> and a motor <NUM> that gives a torque to the gripping clamp <NUM>. The motor <NUM> is supported by the support plate <NUM>. A rotary shaft 41a of the motor <NUM> and the gripping clamp <NUM> are linked together by a belt <NUM>. The belt <NUM> is a transmission member that transmits the power of the motor <NUM> to the gripping clamp <NUM>. Note however that the transmission member is not limited to the belt <NUM>, but may be a transmission member of any other form such as a gear, a chain, or the like. While the motor <NUM> is an example of an actuator that gives a torque to the gripping clamp <NUM>, the actuator that provides a torque to the gripping clamp <NUM> is not limited to the motor <NUM>. In the present embodiment, the rotating device <NUM> is configured to rotate the sheath tip portion 5A by rotating the gripping clamp <NUM>.

The pull-out device <NUM> is configured to pull out the sheath tip portion 5A by moving the gripping clamp <NUM> away from the retention clamp <NUM> along the longitudinal direction of the multi-core cable <NUM>. The pull-out device <NUM> includes a movable base <NUM> that supports the gripping device <NUM> and the rotating device <NUM>, a motor <NUM> that moves the movable base <NUM> forward and rearward, and a fixed base <NUM> that supports the movable base <NUM> and the motor <NUM>. A rail <NUM> that extends in the front-back direction is provided on the fixed base <NUM>. A slider <NUM> that slidably engages with the rail <NUM> is fixed to the lower right portion of the movable base <NUM>. A ball screw <NUM> is connected to the motor <NUM>. As shown in <FIG>, a slider <NUM> that engages with the ball screw <NUM> is fixed to the lower left portion of the movable base <NUM>. The slider <NUM> has a hole (not shown) into which the ball screw <NUM> is inserted. The inner circumference of this hole has a spiral groove formed thereon that engages with the ball screw <NUM>. When the motor <NUM> rotates in one direction, the ball screw <NUM> rotates in the same direction and the slider <NUM> moves forward. As a result, the gripping clamp <NUM> moves forward. When the motor <NUM> rotates in the opposite direction, the ball screw <NUM> also rotates in the opposite direction and the slider <NUM> moves rearward. As a result, the gripping clamp <NUM> moves rearward. Thus, as the motor <NUM> rotates in one direction or in the opposite direction, the gripping clamp <NUM> moves forward or rearward.

The control device <NUM> controls the retention device <NUM>, the gripping device <NUM>, the pull-out device <NUM> and the rotating device <NUM>. As shown in <FIG>, the control device <NUM> is a computer including a CPU 50A, a ROM 50B, a RAM 50C, etc. The control device <NUM> is communicatively connected to the actuator <NUM> of the retention device <NUM>, the actuator <NUM> of the gripping device <NUM>, the motor <NUM> of the pull-out device <NUM>, and the motor <NUM> of the rotating device <NUM>. The control device <NUM> may be a dedicated computer for the untwisting device <NUM> or a general-purpose computer such as a personal computer.

<FIG> is a functional block diagram of the control device <NUM>. The control device <NUM> functions as a pull-out control section <NUM> and a rotary pull-out control section <NUM> as follows by executing a computer program stored in the ROM 50B or an external storage device, etc..

The pull-out control section <NUM> performs a control (hereinafter referred to as "first control") of pulling out the sheath tip portion 5A without rotating the sheath tip portion 5A. Specifically, the pull-out control section <NUM> drives the motor <NUM> of the pull-out device <NUM> while stopping the motor <NUM> of the rotation device <NUM>. As a result, the gripping clamp <NUM>, which grips the sheath tip portion 5A, moves forward without rotating.

The rotary pull-out control section <NUM> performs a control of pulling out the sheath tip portion 5A while rotating it (hereinafter referred to as "second control"). Specifically, the rotary pull-out control section <NUM> drives the motor <NUM> of the pull-out device <NUM> while driving the motor <NUM> of the rotating device <NUM>. Then, the gripping clamp <NUM>, which grips the sheath tip portion 5A, moves forward while rotating. The second control is performed following the first control. In the present embodiment, the first control and the second control are repeated a plurality of times from the start until the end of the pulling-out of the sheath tip portion 5A. Note that the direction in which the core wires <NUM> and the drain wire <NUM> in the sheath <NUM> are twisted (hereinafter referred to as the twist direction) is known in advance. In the second control, the sheath tip portion 5A is rotated in the opposite direction to the twist direction of the core wires <NUM> and the drain wire <NUM>.

The untwisting device <NUM> is configured as described above. Next, the method for pulling out the sheath tip portion 5A using the untwisting device <NUM> will be described. In the following description, the method of pulling out the sheath tip portion 5A at a constant speed while rotating the sheath tip portion 5A at a constant rotation angle from the start until the end of the pulling-out of the sheath tip portion 5A will be called the "conventional method". The pull-out method of the present embodiment will be explained in contrast to the conventional method.

Let L [mm] be the length of the sheath tip portion 5A to be pulled out (i.e., the strip length), and α [degrees] be the total amount of rotation of the sheath tip portion 5A from the start until the end of the pulling-out. In the conventional method, the sheath tip portion 5A moves forward at a constant speed while rotating at a constant rotation angle from the start until the end of the pulling-out, so the amount of rotation per unit travel distance of the sheath tip portion 5A is α/L [degrees/mm]. For example, where L = <NUM> [mm] and α = <NUM> [degrees], the sheath tip portion 5A is pulled out while rotating under α/L = <NUM> [degrees/mm].

On the other hand, in the present embodiment, as shown in <FIG>, the period from the start until the end of the pulling-out of the sheath tip portion 5A is divided into eight sections, and the first control and the second control are repeated four times. The symbols C1 and C2 in the figures represent sections where the first control and the second control are performed, respectively. In the first control, the sheath tip portion 5A is pulled out <NUM> at a constant speed without rotation. In the second control, the sheath tip portion 5A is pulled out at a constant speed while rotating the sheath tip portion 5A at a constant speed as with the conventional method. However, in the present embodiment, the total amount of rotation α = <NUM> [degrees] is made by performing the second control a total of four times, so the amount of rotation per iteration of the second control is <NUM>/<NUM> = <NUM> [degrees]. The amount of rotation α/L per unit travel distance in the second control is <NUM>/<NUM> = <NUM> [degrees/mm], which is twice that of the conventional method.

<FIG> represents three sample multi-core cables where the sheath tip portion 5A is pulled out by the method according to the present embodiment. <FIG> represents three sample multi-core cables where the sheath tip portion 5A is pulled out by the conventional method. As can be seen from the comparison between <FIG>, according to the present embodiment, the kinks in the core wires <NUM> and the drain wire <NUM> are corrected more desirably than with conventional techniques.

With the multi-core cable <NUM>, a frictional force is generated between the sheath tip portion 5A and the core wires <NUM> and between the sheath tip portion 5A and the drain wire <NUM>. As the sheath tip portion 5A is rotated, this frictional force transmits a torque on the core wires <NUM> and the drain wire <NUM>, thereby correcting kinks. However, since the sheath tip portion 5A is pulled forward, the core wires <NUM> and the drain wire <NUM> are also pulled forward by the frictional force. Here, since the core wires <NUM> and the drain wire <NUM> are twisted, they come into close contact with each other when pulled. If the core wires <NUM> and the drain wire <NUM> are in close contact with each other, it is assumed that the kinks in the core wires <NUM> and the drain wire <NUM> cannot be corrected sufficiently unless the sheath tip portion 5A is rotated relatively significantly. In the conventional method, it is assumed that the kinks in the core wires <NUM> and the drain wire <NUM> cannot be corrected sufficiently because the amount of rotation per unit travel distance of the sheath tip portion 5A is relatively small.

In contrast, in the present embodiment, the first control and the second control are performed, and the amount of rotation per unit travel distance of the sheath tip portion 5A is relatively large in the second control. The torque per unit travel distance in the second control is twice that of the conventional method. Therefore, it is assumed that the kinks in the core wires <NUM> and the drain wire <NUM> were corrected sufficiently. Note that while it is possible to rotate the sheath tip portion 5A without pulling out the sheath tip portion 5A, the core wires <NUM> and the drain wire <NUM> may bulge outward in the radial direction from the center of rotation, resulting in buckling, depending on the operating conditions of the device. However, in the second control, the sheath tip portion 5A is rotated while being pulled out. Therefore, it is possible to prevent the buckling of the core wires <NUM> and the drain wire <NUM>.

Now, one may consider increasing the amount of rotation per unit travel distance in the conventional method. For example, one may consider setting it to α/L = <NUM> [degrees/mm] in the conventional method. In that case, however, the total amount of rotation of the sheath tip portion 5A is <NUM> [degrees/mm] × <NUM> [mm] = <NUM> degrees. The total amount of rotation is twice as large. However, if the total amount of rotation is too large, the core wires <NUM> and the drain wire <NUM> may be untwisted excessively in the opposite direction to the twist direction, thereby lowering the quality of the core wires <NUM> and the drain wire <NUM>. There is a risk of creating new kinks in the core wires <NUM> and the drain wire <NUM> in the opposite direction. On the other hand, according to the present embodiment, the sheath tip portion 5A is not rotated in the first control. Therefore, even if the amount of rotation per unit travel distance in the second control is relatively large, the total amount of rotation of the sheath tip portion 5A is not too large.

According to the present embodiment, the sheath tip portion 5A can be pulled out desirably and the kinks in the core wires <NUM> and the drain wire <NUM> can be corrected desirably without detracting from the quality of the core wires <NUM> and the drain wire <NUM>. According to the present embodiment, as with the conventional method, it is possible to simultaneously pull out the sheath tip portion 5A while correcting the core wires <NUM> and the drain wire <NUM>, and it is therefore possible to shorten the cycle time for processing the multi-core cable <NUM>. In addition, according to the present embodiment, the kinks in the core wires <NUM> and the drain wire <NUM> can be corrected more desirably than with conventional techniques, and it is therefore possible to desirably perform subsequent processes on the core wires <NUM> and the drain wire <NUM>. It becomes easier to automate subsequent processes for the core wires <NUM> and the drain wire <NUM>.

Now, if the sheath tip portion 5A is rotated when the sheath tip portion 5A is in the vicinity of the tip of the core wires <NUM> and the drain wire <NUM>, the near-tip portions of the core wires <NUM> and the drain wire <NUM> can be untwisted but the base portions cannot be untwisted. Such a tendency is pronounced particularly when the strip length is long. In the present embodiment, however, the first control and the second control are repeated a plurality of times. Therefore, the core wires <NUM> and the drain wire <NUM> can be untwisted frequently from the start until the end of the pulling-out of the sheath tip portion 5A. In the second control, the kinks can be corrected intensively for the portion where the sheath tip portion 5A has been pulled out in the first control. For example, during the first iteration of the second control, the base portions of the core wires <NUM> and the drain wire <NUM> can be untwisted sufficiently. During the fourth iteration of the second control, the tip portions of the core wires <NUM> and the drain wire <NUM> can be untwisted sufficiently. Therefore, even when the strip length is long, the kinks in the core wires <NUM> and the drain wire <NUM> can be corrected desirably.

In the present embodiment, the sheath tip portion 5A is pulled at the same speed in the first control and the second control. The pull-out speed of the sheath tip portion 5A in the first control is equal to the pull-out speed of the sheath tip portion 5A in the second control. That is, the moving speed of the gripping clamp <NUM> in the first control is equal to the moving speed of the gripping clamp <NUM> in the second control. Therefore, there is no change in the moving speed of the sheath tip portion 5A when transitioning from the first control to the second control and when transitioning from the second control to the first control. Thus, the sheath tip portion 5A can be pulled out stably.

In the present embodiment, the pull-out length is <NUM> both in the first control and in the second control. The pull-out length in the first control is equal to the pull-out length in the second control. Thus, it is possible to desirably pull out the sheath tip portion 5A, and it is possible to more desirably correct the kinks in the core wires <NUM> and the drain wire <NUM>.

In the present embodiment, the pull-out length is <NUM> in any of the first to fourth iterations of the first control. The pull-out length is <NUM> in any of the first to fourth iterations of the second control. The pull-out length of the first control is equal between different iterations. The pull-out length of the second control is equal between different iterations. This simplifies the first control and the second control. It is also possible to evenly untwist the core wires <NUM> and the drain wire <NUM>.

With the untwisting device <NUM> according to the present embodiment, the rotating device <NUM> is configured to rotate the gripping clamp <NUM>. The sheath tip portion 5A is rotated by rotating the gripping clamp <NUM>, which grips the sheath tip portion 5A. Therefore, it is possible to stably rotate the sheath tip portion 5A. Therefore, it is possible to stably perform the first control and the second control. With the configuration in which the sheath tip portion is rotated by moving the upper member and the lower member, which clamp the sheath, in opposite directions (see Utility Model Application Publication No. <CIT>), there is a need to ensure a sufficient dimension (i.e., the length in the moving direction) of the upper member and the lower member taking into account the amount of rotation of sheath tip portion. Therefore, if the amount of rotation of the sheath tip portion is large, the upper member and the lower member become larger. On the other hand, with the rotating device <NUM> according to the present embodiment, the gripping clamp <NUM> does not become larger even if the amount of rotation of the sheath tip portion 5A is large. Thus, regardless of the amount of rotation of the sheath tip portion 5A, the gripping clamp <NUM> can be made smaller.

Note that, in the untwisting device <NUM>, there is no particular limitation on the travel distance of the gripping clamp <NUM> when pulling out the sheath tip portion 5A. In other words, there is no particular limitation on the length of the sheath tip portion 5A to be pulled out (the strip length). Note however that, typically, the longer the strip length, the more difficult it is to correct the kinks in the core wires <NUM> and the drain wire <NUM>. Therefore, the longer the strip length of the multi-core cable <NUM>, the more pronounced the effect of the untwisting device <NUM> according to the present embodiment, i.e., the effect of desirably correcting the kinks in the core wires <NUM> and the drain wire <NUM>. For example, when the strip length is <NUM> mm or more, the untwisting device <NUM> according to the present embodiment is particularly effective. The control device <NUM> may be configured to pull out the sheath tip portion 5A by <NUM> or more from the start until the end of the pulling-out of the sheath tip portion 5A.

While one embodiment of the present invention has been described above, the embodiment is merely an example and various other embodiments are possible. Next, examples of other embodiments will be described.

In the embodiment described above, the pull-out length in the first control and the pull-out length in the second control are equal, both being <NUM>. However, the pull-out length in the first control and the pull-out length in the second control may be different. For example, as shown in <FIG>, when the strip length is <NUM>, the pull-out length in the first control may be <NUM> and the pull-out length in the second control may be <NUM>. In this case, the pull-out length in the second control (= <NUM>) is <NUM>/<NUM> of the total pull-out length in the first control and the second control (= <NUM>). The amount of rotation in the second control can be set as desired. For example, the amount of rotation per unit travel distance α/L in the second control may be three times the amount of rotation per unit travel distance α/L according to the conventional method. Note that the pull-out length in the first control may be longer or shorter than the pull-out length in the second control.

In the embodiment described above (see <FIG>), the pull-out length is equal in each iteration of the first control and the pull-out length is equal in each iteration of the second control. For example, the pull-out length of the first iteration of the first control is <NUM>, and the pull-out length of the second iteration of the first control is <NUM>. However, the pull-out length may differ between a plurality of iterations of the first control. The pull-out length may also differ between a plurality of iterations of the second control. For example, as shown in <FIG>, the pull-out length of the first iteration of the first control may be <NUM>, and the pull-out length of the second iteration of the first control may be <NUM>.

Where the first control and the second control are performed for a plurality of iterations, the amount of rotation per unit travel distance α/L may be constant for different iterations. Thus, it is possible to evenly correct the kinks in the core wires <NUM> and the drain wire <NUM>. αn/La = αn+<NUM>/Ln+<NUM> may hold, where n is a predetermined natural number, Ln is the total pull-out length for the nth iteration of the first control and the second control, αn is the amount of rotation of the nth iteration of the second control, Ln+<NUM> is the total pull-out length for the n+<NUM>th iteration of the first control and the second control, and αn+<NUM> is the amount of rotation of the n+<NUM>th iteration of the second control. For example, in the example shown in <FIG>, since L1 = <NUM> and L2 = <NUM>, α1/<NUM> = α2/<NUM> may be set. Then, α2 = <NUM>×α1.

In the example described above, L2 is shorter than L1, and α2 is smaller than α1. Thus, where the first control and the second control are performed for a plurality of iterations, the amount of rotation may be set to be smaller as the total pull-out length for each iteration is shorter. Where the total pull-out length of the nth iteration of the first control and the second control is shorter than the total pull-out length of the mth iteration (where m is a predetermined natural number other than n) of the first control and the second control, the amount of rotation of the nth iteration of the second control may be smaller than the amount of rotation of the mth iteration of the second control. Thus, the kinks in the core wires <NUM> and the drain wire <NUM> can be corrected relatively evenly.

The pull-out speed may be equal or may differ between the first control and the second control. The pull-out speed may differ between iterations of the first control. The pull-out speed may difference between iterations of the second control. For example, the pull-out speed may become higher or lower for later iterations.

The first control and the second control may be performed only for one iteration. For example, for the multi-core cable <NUM> with a short strip length, the kinks in the core wires <NUM> and the drain wire <NUM> can be corrected desirably even if the first control and the second control are performed only for one iteration.

While the first control is performed immediately after the start of the pulling-out of the sheath tip portion 5A in the embodiment described above, the second control may be performed immediately after the start of the pulling-out.

While the sheath tip portion 5A is not rotated in the first control in the embodiment described above, the sheath tip portion 5A may be pulled out while being rotated in the first control. Where the total amount of rotation of the sheath tip portion 5A is constant, the amount of rotation per unit travel distance α/L in the second control can be made larger than with conventional techniques by making the amount of rotation per unit travel distance α/L in the first control smaller than with conventional techniques. For example, in the first control, the sheath tip portion 5A is pulled out while being rotated at the first rotation speed, and in the second control, the sheath tip portion 5A is pulled out while being rotated at the second rotation speed greater than the first rotation speed. Even with such a control, α/L in the second control can be made larger than with the conventional method. Therefore, the kinks in the core wires <NUM> and the drain wire <NUM> can be corrected more desirably than with the conventional method.

Only the first control and the second control may be performed from the start until the end of the pulling-out of the sheath tip portion 5A, or other controls may be performed in addition to the first control and the second control. For example, immediately after the start of the pulling-out of the sheath tip portion 5A, a control may be performed to pull out the sheath tip portion 5A while rotating the sheath tip portion 5A in the same direction as the twist direction of the core wires <NUM> and the drain wire <NUM>, and the first control and the second control may be performed thereafter. Note that while the sheath tip portion 5A is pulled out while being rotated in the second control, the rotation direction in this operation is the opposite direction to the twist direction of the core wires <NUM> and the drain wire <NUM>.

There is no particular limitation on the method for rotating the sheath tip portion 5A. There is no particular limitation on the configuration for rotating the sheath tip portion 5A. For example, the gripping clamp <NUM> may include a pair of upper and lower clamp members, and these clamp members may be configured to move in opposite directions to each other in the left-right direction while clamping the sheath tip portion 5A. In this case, the sheath tip portion 5A is rotated by being rolled by the pair of upper and lower clamp members.

In the embodiment described above, the sheath tip portion 5A is rotated while the non-tip portion 5B of the sheath <NUM> is held stationary. However, it is sufficient to be able to rotate the sheath tip portion 5A relative to the non-tip portion 5B, and there is no particular limitation on the configuration and operation of the rotating device. The non-tip portion 5B of the sheath <NUM> may be rotated while not rotating the sheath tip portion 5A. Both the sheath tip portion 5A and the non-tip portion 5B may be rotated in opposite directions of each other.

There is no particular limitation on the configuration of the gripping clamp <NUM>. The gripping clamp <NUM> may include any configuration capable of gripping the sheath tip portion 5A. For example, the gripping clamp <NUM> may be provided with a pair of plate-like members that grip the sheath tip portion 5A instead of the first clamp jaw <NUM> and the second clamp jaw <NUM>.

In the present embodiment, the multi-core cable <NUM> includes four core wires <NUM> and one drain wire <NUM>. However, there is no particular limitation on the number of core wires <NUM> and the number of drain wires <NUM>. The drain wire <NUM> may not be necessary. The multi-core cable <NUM> may include a plurality of covered electric wires and include no uncovered electric wire. The multi-core cable <NUM> may include a plurality of uncovered electric wires and include no covered electric wire.

Claim 1:
A multi-core cable untwisting device (<NUM>) for pulling out a tip portion (5A) of a sheath (<NUM>) of a multi-core cable (<NUM>), which includes a plurality of electric wires (<NUM>) and the sheath (<NUM>) that covers the electric wires (<NUM>), while correcting kinks in the electric wires (<NUM>), the multi-core cable untwisting device (<NUM>) comprising:
a retention member (<NUM>) configured to retain a non-tip portion (5B) of the sheath (<NUM>) that has a cut between the tip portion (5A) and the non-tip portion (5B);
a gripping member (<NUM>) configured to grip the tip portion (5A) of the sheath (<NUM>);
a pull-out device (<NUM>) configured to pull out the tip portion (5A) of the sheath (<NUM>) by moving at least one of the gripping member (<NUM>) and the retention member (<NUM>) so that the gripping member (<NUM>) moves away from the retention member (<NUM>);
a rotating device (<NUM>) configured to relatively rotate the tip portion (5A) of the sheath (<NUM>) that is gripped by the gripping member (<NUM>) and the non-tip portion (5B) of the sheath (<NUM>); and
a control device (<NUM>) configured to control the pull-out device (<NUM>) and the rotating device (<NUM>),
characterized in that
the control device (<NUM>) is configured to perform a first control and a second control from start until end of the pulling-out of the tip portion (5A) of the sheath (<NUM>), wherein the first control is to control the pull-out device (<NUM>) and the rotating device (<NUM>) so that the amount of rotation per unit travel distance of the tip portion (5A) of the sheath (<NUM>) is smaller than a predetermined amount of rotation, and the second control is to control the pull-out device (<NUM>) and the rotating device (<NUM>) so that the amount of rotation per unit travel distance of the tip portion (5A) of the sheath (<NUM>) is equal to or greater than the predetermined amount of rotation.