JP3521211B2 - Web unwinding device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biaxial unwinding device capable of continuously unwinding a web of film, paper or the like.

[0002]

2. Description of the Related Art As a device for continuously unwinding a web of film, paper or the like, there is a biaxial unwinding device capable of exchanging an unwinding base material (web) without stopping a conveying line. This unwinding device has a shaft with less unwound web remaining (hereinafter referred to as the old shaft) and a new shaft with the web fully wound (hereinafter referred to as the new shaft),
The web unwound from the old shaft is bonded to the web unwound from the new shaft, and the web is automatically replaced (spliced).

A biaxial web unwinding device is shown in FIG.
~ It demonstrates based on FIG.

FIGS. 5 to 9 are side views of the unwinding device 1 for the web W, and FIG. 10 is a plan view of the unwinding device 1.

A supporting body 2 is rotatably supported by supporting legs 43, 43 provided upright from a base 42 of the unwinding device 1, and two pairs of arms 4 and 5 project from the supporting body 2 in pairs. An old shaft 6 is rotatably supported by the pair of arms 4 and 4, and a new shaft 7 is rotatably supported by the pair of arms 5 and 5. Then, the old shaft 6 and the new shaft 7 rotate in synchronization with each other by a motor.

Below the support body 2, a rotatable splice arm 8 is provided. The splice arm 8 is
A guide roll 10 is provided in a direction opposite to the rotating shaft 9 of the above, and a cutter 12 and a nip roll 14 are provided inside thereof. The cutter 12 can be moved by an air cylinder as will be described later, and the nip roll 14 can also be moved by an air cylinder.

The splicing process of the unwinding device 1 will be described below with reference to FIGS.

1. Splicing start step (see FIG. 5) When the web W from the old shaft 6 is running low, a new web W is set on the new shaft 7 to prepare for splicing.

As a preparatory operation, the support 2 rotates in the forward rotation direction (the rotation direction opposite to the clockwise hand).

2. Pre-stop step (see FIG. 6) When the support body 2 turns on the limit switch (not shown), the rotation thereof is stopped once, and the splice arm 8 is changed from the solid line position (standby position) in FIG. 6 to the dotted line state. It rotates about the rotary shaft 9. When the movement of the splice arm 8 is completed, the support 2 rotates again.

3. Step of reading the radius of the new shaft (see FIG. 7) At the position where the radius of the new shaft 7 is read, the rotation of the support 2 is stopped and the radius of the new shaft 7 is read. The operator inputs the read value in advance. When the radius of the new shaft 7 is read, the new shaft 7 is rotated by the motor at the same speed as the speed (line speed) at which the web W is unwound from the new shaft 7, judging from the read radius.

4. Cutting start step (see FIG. 8) The double-sided tape 16 provided on the outer peripheral surface of the new shaft 7 passes as a pre-operation for cutting the web W unwound from the old shaft 6 (hereinafter referred to as the old web W). Before this, the nip roll 14 is operated by an air cylinder. The actuated nip roll 14 has the old web W on the outer peripheral surface of the new shaft 7.
To prepare for bonding when the double-sided tape 16 passes.

5. Laminating step (see FIG. 9) When the double-sided tape 16 provided on the outer peripheral surface of the new shaft 7 passes the position of the old web W pressed by the nip roll 14, it is unwound from the old web W and the new shaft 7. The bonding of the web W (hereinafter referred to as the new web W) is completed.

6. Cutting Step (See FIG. 9) After that, the old web W is cut by the cutter 12 leaving only the tail length. After the cutting is completed, the splice arm 8 returns to the standby position, and the splicing ends.

[0015]

By the way, in order to determine the timing of the above-mentioned bonding step and cutting step, it is necessary to detect the position of the double-sided tape 16 which moves with the rotation of the new shaft 7.

Therefore, as shown in FIG. 11, the new shaft 7
A semicircular detection plate 18 is provided coaxially with the new shaft 7 on the end face of the, and when the detection plate 18 rotates to a predetermined position, the detection sensor 20 including a proximity switch is turned on. The double-sided tape 16 is set to move to a position where the nip roll 14 will move when the ON state is set. That is, the double-sided tape 16 moves to the position indicated by the double-sided tape position mark 44.

The detection sensor 20 and the double-sided tape 16
As shown in FIG. 11, the position of the detection sensor 20 and the double-sided tape 16 are attached so that the positions of the detection sensor 20 and the double-sided tape 16 are at a predetermined angle (for example, 90 °). . On the other hand, the detection sensor 20 is attached to the arm 5 that fixes the new shaft 7. Therefore, the following problems occur.

As shown in FIG. 11, the rotation axis O of the support 2 is
The position between the rotation axis P of the new shaft 7 and the sticking position Q of the nip roll 14 is a predetermined angle (for example, 90 °) as described above.
It is fixed at. Therefore, if the radius of the new shaft 7 is always the same, the bonding position is always the same.

However, the web W wound around the new shaft 7
When the radius r2 wound around the radius r0 of the new shaft 7 (hereinafter, referred to as a reference diameter) such that the predetermined angle is obtained is smaller than the radius r2, as shown in FIG. The bonding position comes before the bonding position of the reference diameter r0. Then, when the old web W is cut by the cutter 12, the tail length from the bonding position to the cutting position becomes shorter than the tail length at the reference diameter r0.

On the contrary, a diameter r larger than the reference diameter r0
When the new shaft 1 of No. 1 is attached, since the bonding position is behind the position of the reference diameter r0, the tail length becomes longer than the tail length of the reference diameter r0. .

As described above, when the tail length of the old web W is different depending on the diameter of the new shaft, the tail of the old web W becomes a nozzle or the like of the heat treatment device in a treatment process such as heat treatment after unwinding the web W. There was a problem that the web W was scratched by touching.

In view of the above problems, the present invention ensures that the old web has the same tail length even if a new shaft having a small diameter other than the reference diameter or a new shaft having a large diameter is attached to the new shaft. An unwinding device for the web W is provided.

[0023]

The web unwinding device according to the first aspect of the present invention is provided with two sets of rotatably mounted shafts around which the web is wound between a pair of arms.
In the web unwinding device in which the web is unwound, the new shaft is rotated from the old shaft near the end of unwinding the web to the new shaft with the web fully wound. Synchronous rotation means for rotating in synchronization with the old shaft, reference position detecting means for detecting a reference position indicating the position of an adhesive member provided on the outer peripheral surface of the new shaft from the posture of the arm, and Connecting means for connecting, via the adhesive member, an old web near the end of unwinding and a new web wound on a new shaft rotated by the synchronous rotation means, and the both webs by the connection means. When the cutting means for cutting the old web after the connection and the new shaft having the reference diameter r0 are attached, the connection is made after the first reference timing N1 from the time when the reference position detection means detects the reference position. Along with performing connection by stage,
The second from the time when the reference position detecting means detects the reference position.
The cutting is performed by the cutting means after the reference timing N2, and the diameter r1 (r0 <r is larger than the reference diameter r0.
When the new shaft of 1) is attached, the first reference timing N starts from the time when the reference position detecting means detects the reference position.
The connection timing is after the connection timing N3 which is earlier than 1, and the disconnection timing N4 which is earlier than the second reference timing N2 from the time when the reference position detection means detects the reference position.
And a control unit that controls the cutting unit to perform the cutting later.

According to a second aspect of the present invention, there is provided a web unwinding device according to the first aspect, further comprising a pulse generator that transmits a pulse based on a rotation angle of the new shaft, and the control means has the first reference timing. N1, the second reference timing N2, the contact timing N3, and the disconnection timing N4 are calculated based on the number of pulses transmitted by the pulse generator.

According to a third aspect of the present invention, there is provided the web unwinding device according to the second aspect, wherein the control means calculates the first reference timing N1 based on the equation (1) and determines the second reference timing N2. It is calculated based on the equation (2).

N1 = A × n−B (1) N2 = A × n + C (2) where A is the number of pulses per revolution of the new shaft, n
Is the number of revolutions of the new shaft from the detection of the reference position until the webs are connected, and B is based on the time for connecting the webs by the connecting means and the operation delay time of the connecting means. The calculated rotation angle of the new axis, C, is
It is a rotation angle of the new shaft calculated based on a time obtained by subtracting an operation delay time of the cutting means from a time when a predetermined tail length of the old web is unwound.

A web unwinding device according to a fourth aspect of the present invention calculates the connection timing N3 based on the equation (3) and the cutting timing N4 based on the equation (4).

N3 = A × n−B−D (3) N4 = A × n + C−D (4) where D is A × θ1 / 360 and θ1 is (5)
It is calculated based on the formula.

Cos (90−θ1) = (r1 ² −r0 ² ) / (2 × r1 × L) ··· (5) where L is the length of the arm.

According to a fifth aspect of the present invention, there is provided a web unwinding device according to the fourth aspect, in which two sets are provided, in which a shaft around which the web is wound is rotatably attached between a pair of arms.
In the web unwinding device in which the web is unwound, the new shaft is rotated from the old shaft near the end of unwinding the web to the new shaft with the web fully wound. Synchronous rotation means for rotating in synchronization with the old shaft, reference position detecting means for detecting a reference position indicating the position of an adhesive member provided on the outer peripheral surface of the new shaft from the posture of the arm, and Connecting means for connecting, via the adhesive member, an old web near the end of unwinding and a new web wound on a new shaft rotated by the synchronous rotation means, and the both webs by the connection means. When the cutting means for cutting the old web after the connection and the new shaft having the reference diameter r0 are attached, the connection is made after the first reference timing N6 from the time when the reference position detection means detects the reference position. Along with performing connection by stage,
The second from the time when the reference position detecting means detects the reference position.
The cutting is performed by the cutting means after the reference timing N7, and the diameter r2 (r0> r) smaller than the reference diameter r0.
When the new shaft of 2) is attached, the first reference timing N from the time when the reference position detecting means detects the reference position.
The connection timing is after the connection timing N8, which is later than 1, and the disconnection timing N9, which is later than the second reference timing N7, from the time when the reference position detection means detects the reference position.
And a control unit that controls the cutting unit to perform the cutting later.

According to a sixth aspect of the present invention, there is provided a web unwinding device according to the fifth aspect, further comprising a pulse generator that emits a pulse based on a rotation angle of the new shaft, and the control means has the first reference timing. N6, the second reference timing N7, the contact timing N8, and the disconnection timing N9 are calculated based on the number of pulses transmitted by the pulse generator.

According to a seventh aspect of the present invention, in the web unwinding apparatus according to the sixth aspect, the control means calculates the first reference timing N6 based on the equation (6) and determines the second reference timing N7. It is calculated based on the equation (7).

N6 = A × n−B (6) N7 = A × n + C (7) where A is the number of pulses per revolution of the new shaft, n
Is the number of revolutions of the new shaft from the detection of the reference position until the webs are connected, and B is based on the time for connecting the webs by the connecting means and the operation delay time of the connecting means. The calculated rotation angle of the new axis, C, is
It is a rotation angle of the new shaft calculated based on a time obtained by subtracting an operation delay time of the cutting means from a time when a predetermined tail length of the old web is unwound.

A web unwinding device according to an eighth aspect is the same as that according to the seventh aspect, wherein the connection timing N5 is (8).
The disconnection timing N6 is calculated according to the equation (9).
It is calculated based on an expression.

N8 = A × n−B + E (8) N9 = A × n + C + E (9) where E is A × θ2 / 360 and θ2 is (1
It is calculated based on the equation (0).

[0036] ^{cos (90 + θ2) = (} r2 2 -r0 2) / (2 × r2 × L) ·· (10) In addition, L is the length of the arm.

[0037]

[Operation] The tail length of the old web in the web unwinding device according to claim 1 will be described.

When a new shaft having a diameter larger than the reference diameter is attached, it becomes as follows.

After the connection timing N3, which is earlier than the first reference timing N1 since the reference position detecting means detects the reference position, the connecting means connects the old web and the new web. Further, from the time the reference position detecting means detects the reference position, the second reference timing N2
After the cutting timing N4, which is an earlier timing, the cutting means cuts the old web.

Therefore, even when a new shaft having a diameter larger than the reference diameter is attached, the tail length of the old web becomes the same as the tail length of the reference diameter.

In the web unwinding device of the second aspect, the first reference timing N1 and the second reference timing N are provided.
2. Since the contact timing N3 and the cutting timing N4 are calculated based on the number of pulses transmitted by the pulse generator, the cutting can be performed with exactly the same tail length.

In the web unwinding device of the third aspect, the first reference timing N1 is calculated based on the equation (1), and the second reference timing N2 is calculated based on the equation (2). The cutting can be done with the same tail length.

In the web unwinding device of claim 4, the connection timing N3 is calculated based on the equation (3),
Since the cutting timing N4 is calculated based on the equation (4), the cutting can be surely performed with the same tail length.

The tail length of the old web in the web unwinding device of claim 5 will be described.

When a new shaft having a diameter smaller than the reference diameter is attached, it becomes as follows.

The old web and the new web are connected by the connecting means after the connection timing N8 which is earlier than the first reference timing N6 after the reference position detecting means detects the reference position. The second reference timing N7 starts when the reference position detecting means detects the reference position.
After the cutting timing N9 which is earlier, the cutting means cuts the old web.

Therefore, even if a new shaft having a diameter smaller than the reference diameter is attached, the tail length of the old web becomes the same as the tail length of the reference diameter.

In the web unwinding device of the sixth aspect, the first reference timing N6 and the second reference timing N are provided.
7. Since the contact timing N8 and the cutting timing N9 are calculated based on the number of pulses transmitted by the pulse generator, the cutting can be performed accurately with the same tail length.

According to the web unwinding device of claim 7, the first reference timing N6 is calculated based on the equation (6), and the second reference timing N7 is calculated based on the equation (7). The cutting can be done with the same tail length.

In the web unwinding device of claim 8, the connection timing N8 is calculated based on the equation (8),
Since the cutting timing N9 is calculated based on the equation (9), it is possible to surely cut with the same tail length.

[0051]

BEST MODE FOR CARRYING OUT THE INVENTION An unwinding device according to an embodiment of the present invention will be described below with reference to FIGS.

The structure of the unwinding device 1 for the web W is the same as the structure shown in the "Prior Art" section, and the splicing process includes splicing start process, pre-stop process and new shaft diameter. It is the same until the reading process. And
Since this step is different from the next cutting start step, this step will be described in detail in this embodiment.

First, a block diagram of the unwinding device 1 of this embodiment will be described with reference to FIG.

The control unit 22 composed of a personal computer or the like includes an old shaft rotary motor 24 which is a motor for rotating the old shaft 6 and a new shaft rotary motor 26 which is for rotating the new shaft 7.
The control unit is connected to a support rotation motor 28 that rotates the support 2, an air cylinder 30 that moves the splice arm 8, an air cylinder 32 that moves the nip roll 14, and an air cylinder 34 that moves the cutter 12. An operation unit 36 for operating 22 is connected.
Pulse generators 38 and 40 for detecting the number of rotations of the old shaft rotary motor 24 and the new shaft rotary motor 26 are connected to each other, whereby a pulse is transmitted based on the rotation angle of the old shaft 6 and the new shaft 7 is rotated. A pulse is emitted based on the rotation angle. In addition, the detection plate 18 for detecting the position of the double-sided tape 16 shown in the section "Problems to be solved by the invention"
The detection sensor 20 which is turned on in is connected.

The nip process and the cutting process will be described below.

(1. When the new shaft 7 having the reference diameter r0 is attached) When the new shaft 7 having the reference diameter r0 is attached FIG.
It will be described based on.

As shown in FIG. 1, the reference diameter r0 means the rotation axis O of the support 2, the rotation axis P of the new shaft 7 and the nip roll 14.
Is the diameter of the new shaft 7 having a radius such that the line connecting the bonding positions Q is at a right angle.

(1) Nip Process The timing N1 of pressing the nip roll 14 against the outer peripheral surface of the new shaft 7 is set before the double-sided tape 16 provided on the outer peripheral surface of the new shaft 7 passes. Equation (11) is used as an arithmetic expression therefor. N1 is the number of pulses.

N1 = a × n−b (11) However, a, n, and b are as follows.

A is the number of pulses per revolution of the new shaft 7.

At n, the detection plate 18 turns on the detection sensor 20.
It is the number of rotations of the new shaft 7 from the state of the state until the nip process is performed.

Reference numeral b denotes a nip roll 14 and a double-sided tape 16
The new shaft 7 calculated based on the total time of the time until the nip roll 14 reaches the outer peripheral surface of the new shaft 7 by pressing the Is the rotation angle of. That is,
b is a rotation angle obtained by comparing the connection time of the nip roll 14 and the operation delay time with the rotation speed of the new shaft 7.

(2) Cutting Step The cutting timing N2 by the cutter 12 is performed after the double-sided tape 16 has passed and the specified tail length has moved.

Specifically, the calculation is performed by the equation (12). N2 is the number of pulses.

N2 = a × n + c (12) However, c is calculated based on the time obtained by subtracting the operation delay time of the cutter 12 from the time when the specified tail length of the old web W is unwound. Is the rotation angle of the new shaft 7.

As described above, the tail length M of the old web W is determined on the new shaft 7 having the reference diameter r0.

(2. When a new shaft 7 having a diameter r1 larger than the reference diameter r0 is attached) When a new shaft 7 having a diameter r1 larger than the reference diameter r0 is attached, as shown in FIG. After the detection sensor 20 is turned on, the double-sided tape 16 passes after the rotation angle θ1.
It is necessary to correct 1.

(1) Nip process In the nip process, taking n1 into consideration, the nip roll 1
The timing N3 of the nip of No. 4 is measured.

Specifically, this is performed by the equation (13). N3 is the number of pulses.

N3 = a × n−b−d (13) However, d is a × θ1 / 360 °, and θ1 is shown in FIG.
As shown in, calculated from the cosine theorem based on equation (14). Note that L is the length of the arm, that is, the rotation axis O
And the axis of rotation P.

Cos (90−θ1) = (r1 ² −r0 ² ) / (2 × r1 × L) ··· (14) As a result, the double-sided tape 16 passes after the detection plate 18 turns on the detection sensor 20. Reference time r
Even if it is different from 0, the nip can be started at the same position as the reference diameter r0.

(2) Cutting Step The cutting timing N4 is also corrected by the angle of θ1 as in the nip timing. In particular,
The calculation is performed using the equation (14). N4 is the number of pulses.

N4 = a × n + c−d (15) As a result, the nip timing N3 and the cut timing N4 become the same as the reference diameter r0, that is, the normal line (right angle to the extending direction of the arm 5). Since the nipping is performed at the position in the () direction and the cutting is performed in accordance with the nipping, the tail length M of the old web W becomes the same as the tail length of the reference diameter r0.

(3. When a new shaft 7 having a diameter r2 smaller than the reference diameter r0 is attached) When a new shaft 7 having a diameter r2 smaller than the reference diameter r0 is attached, the detection plate 18 is the detection sensor 2
Since the double-faced tape 16 passes by θ2 earlier than the bonding surface after turning 0 on, the angle θ2 is corrected.

(1) Nip process In the nip process, the nip roll 1 is considered in consideration of θ2.
The timing N8 of the nip of No. 4 is measured.

Specifically, this is performed by the equation (16). N8 is the number of pulses.

N8 = a × n−b + e (16) However, θ2 is (17) from the cosine theorem as shown in FIG.
It is calculated based on the formula.

Cos (90 + θ2) = (r2 ² −r0 ² ) / (2 × r2 × L) ··· (17) (2) Cutting process The cutting timing N9 is also corrected by θ2 in the same manner as the nip timing. Since it is necessary, the calculation is performed using the equation (18).

N9 = a × n + c + e (18) As a result, the nip timing N8 and the cut timing N9 are the same as those of the reference diameter r0, that is,
Since the nipping is performed at the position of the normal (right angle) direction to the extending direction of the arm 5 and the cutting is performed accordingly, the tail length M of the old web W becomes the same as the tail length of the reference diameter r0.

(4. Effect of the Embodiment) As described above, if the tail length when the new shaft 7 having the reference diameter r0 is attached is determined, the new shaft 7 having the diameter r2 smaller than the reference diameter r0 and the large diameter. Even when the new shaft 7 of r1 is attached, the old web W can be cut with the same tail length. Therefore, after the splicing process, the problem due to the difference in tail length does not occur.

[0081]

As described above, in the web unwinding device of the present invention, the diameter r2 smaller than the reference diameter r0 and the large diameter r are smaller.
Even when the new shaft 1 is attached, the tail length of the old web can be cut constantly.

[Brief description of drawings]

FIG. 1 shows an unwinding device 1 according to an embodiment of the present invention, in which a new shaft having a reference diameter r0 is attached.

FIG. 2 is a diagram when a new shaft having a diameter r1 larger than the reference diameter r0 is also attached.

FIG. 3 is a diagram when a new shaft having a diameter r2 smaller than the reference diameter r0 is also attached.

FIG. 4 is a block diagram of an unwinding device.

FIG. 5 is an explanatory diagram of a splice starting step in the unwinding device.

FIG. 6 is an explanatory diagram of a pre-stop step.

FIG. 7 is an explanatory diagram of a new shaft diameter reading process.

FIG. 8 is an explanatory diagram of a cutting start process.

FIG. 9 is an explanatory diagram of a bonding process and a cutting process.

FIG. 10 is a plan view of the unwinding device.

FIG. 11 is an explanatory diagram when a new shaft having a reference diameter r0 is attached to a conventional unwinding device.

FIG. 12 is an explanatory diagram when a new shaft having a diameter r2 smaller than the reference diameter r0 is also attached.

FIG. 13 is an explanatory diagram when a new shaft having a diameter r1 larger than the reference diameter r0 is also attached.

[Explanation of symbols]

1 Unwinding device 2 support 6 Old axis 7 New axis 8 splice arms 9 rotation axis 10 Guide roll 12 cutters 14 Nip roll 16 double-sided tape 18 Detection plate 20 detection sensor

Continuation of the front page (56) Reference JP-A-11-59993 (JP, A) JP-A-10-72151 (JP, A) JP-A-9-58911 (JP, A) JP-A-5-278908 (JP , A) JP-A-60-232360 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B65H 19/18

Claims (8)

(57) [Claims] 1. A set of two rotatably mounted shafts around which a web is wound is provided between a pair of arms. Of these two sets, the old shaft near the end of the unwinding of the web is filled with the web. A web unwinding device capable of exchanging a web around a new shaft wound around a winding, in which the new shaft is rotated in synchronization with the rotating old shaft; and the new shaft. Reference position detecting means for detecting a reference position indicating the position of the adhesive member provided on the outer peripheral surface of the arm from the attitude of the arm, an old web near the end of unwinding, and a new shaft rotated by the synchronous rotating means. Connecting means for connecting a new web wound around the web via the adhesive member, cutting means for cutting the old web after connecting both webs by the connecting means, and a new shaft having a reference diameter r0. Take When attached, the connection is made by the connecting means after the first reference timing N1 from the time when the reference position detecting means detects the reference position, and the second reference timing is when the reference position detecting means detects the reference position. Cutting is performed by the cutting means after N2, and a diameter r1 larger than the reference diameter r0 (r0 <r1)
When the new shaft is attached, the connection is performed by the connection means after the connection timing N3, which is earlier than the first reference timing N1 from the time when the reference position detection means detects the reference position, and the reference position detection is performed. Unwinding the web, comprising: control means for controlling the cutting to be performed by the cutting means after the cutting timing N4, which is earlier than the second reference timing N2 when the means detects the reference position. apparatus. 2. A pulse generator that emits a pulse based on a rotation angle of the new shaft, wherein the control means includes the first reference timing N1, the second reference timing N2, the contact timing N3, and the disconnection. 2. The web unwinding device according to claim 1, wherein the timing N4 is calculated based on the number of pulses transmitted by the pulse generator. 3. The control means calculates the first reference timing N1 based on the equation (1) and calculates the second reference timing N2 based on the equation (2). 2. The web unwinding device described in 2. N1 = A × n−B (1) N2 = A × n + C (2) where A is the number of pulses per revolution of the new shaft, and n is after detecting the reference position. The number of revolutions of the new shaft until the webs are connected, B is a rotation angle of the new shaft calculated based on a time for connecting the webs by the connecting means and an operation delay time of the connecting means. , C is a rotation angle of the new shaft calculated based on a time obtained by subtracting an operation delay time of the cutting means from a time when a predetermined tail length of the old web is unwound. 4. The web unwinding device according to claim 3, wherein the connection timing N3 is calculated based on the equation (3), and the cutting timing N4 is calculated based on the equation (4). N3 = A * n-B-D ... (3) N4 = A * n + C-D ... (4) However, D is A * (theta) 1/360 and (theta) 1 is based on (5) Formula. Is calculated. cos (90−θ1) = (r1 ² −r0 ² ) / (2 × r1 × L) (5) where L is the length of the arm. 5. A pair of rotatably attached shafts around which a web is wound is provided between a pair of arms. Of these two sets, the web is fully loaded from the old shaft near the end of the unwinding of the web. A web unwinding device capable of exchanging a web around a new shaft wound around a winding, in which the new shaft is rotated in synchronization with the rotating old shaft; and the new shaft. Reference position detecting means for detecting a reference position indicating the position of the adhesive member provided on the outer peripheral surface of the arm from the attitude of the arm, an old web near the end of unwinding, and a new shaft rotated by the synchronous rotating means. Connecting means for connecting a new web wound around the web via the adhesive member, cutting means for cutting the old web after connecting both webs by the connecting means, and a new shaft having a reference diameter r0. Take When attached, the connection is made by the connecting means after the first reference timing N6 from the time when the reference position detecting means detects the reference position, and the second reference timing is when the reference position detecting means detects the reference position. Cutting is performed by the cutting means after N7, and a diameter r2 smaller than the reference diameter r0 (r0> r2)
When the new shaft is attached, the connection is performed by the connection means after the connection timing N8, which is a timing later than the first reference timing N6 from the time when the reference position detection means detects the reference position, and the reference position detection is performed. The unwinding of the web, the control means controlling the cutting to be performed by the cutting means after a cutting timing N9 which is a timing later than the second reference timing N7 from the time when the means detects the reference position. apparatus. 6. A pulse generator that emits a pulse based on a rotation angle of the new shaft, wherein the control means includes the first reference timing N6, the second reference timing N7, the contact timing N8, and the disconnection. The web unwinding device according to claim 5, wherein the timing N9 is calculated based on the number of pulses transmitted by the pulse generator. 7. The control means calculates the first reference timing N6 based on equation (6), and calculates the second reference timing N7 based on equation (7). A web unwinding device according to item 6. N6 = A × n−B (6) N7 = A × n + C (7) where A is the number of pulses per revolution of the new shaft, and n is after detecting the reference position. The number of revolutions of the new shaft until the two webs are connected, B is a rotation angle of the new shaft calculated based on a time for connecting the two webs by the connecting means and an operation delay time of the connecting means. , C is a rotation angle of the new shaft calculated based on a time obtained by subtracting an operation delay time of the cutting means from a time when a predetermined tail length of the old web is unwound. 8. The web unwinding device according to claim 7, wherein the connection timing N8 is calculated based on the equation (8), and the cutting timing N9 is calculated based on the equation (9). N8 = A × n−B + E (8) N9 = A × n + C + E (9) where E is A × θ2 / 360, and θ2 is calculated based on the equation (10). . cos (90 + θ2) = (r2 ² −r0 ² ) / (2 × r2 × L) ··· (10) Note that L is the length of the arm.