This application is based on Japanese patent application 2020-170181 (filed on Oct. 7, 2020) and enjoys preferential benefits from this application. This application shall include all of the contents of Japanese Patent Application 2020-170181 by reference to Japanese Patent Application 2020-170181.
The present invention relates to a bale rubber holding device and a method for cutting a bale rubber.
A rubber mixture used as a material of a tire is prepared by mixing raw material rubber, a reinforcing material, a functional material, and the like in a predetermined ratio. As the raw material rubber used here, a bale rubber piece cut out from a bale rubber, which is a relatively large mass of rubber, is used.
A bale rubber is delivered to a factory in a form of being wrapped in a resin sheet which does not affect properties of the rubber mixture. The delivered bale rubber is cut by a cutter coming down from above and divided into a plurality of bale rubber pieces as described in PTL 1, and here, the bale rubber is cut together with the resin sheet while being wrapped in the resin sheet.
Normally, a bale rubber is intermittently fed toward a cutting position, and each time it is fed, it is cut by a cutter to cut out a bale rubber piece. In the related art, the bale rubber is fed to the cutting position by pushing a rear portion (a portion opposite to a feeding direction) of the bale rubber.
PTL 1: JP-A-2002-18785
However, since a bale rubber is sticky to a cutter, in a method of the related art, a cut surface of a bale rubber and a rear potion of a bale rubber are lifted when cutting the bale rubber. As a result, a position of the bale rubber may shift. When a resin sheet covering the bale rubber is not cut even when the bale rubber is cut, the position of the bale rubber might shift due to being pulled by the resin sheet. Then, there is a problem that the bale rubber piece cannot be cut out with accurate dimensions at next cutting due to the misalignment of the bale rubber.
Therefore, an object of the invention is to provide a device and a method for facilitating cutting out a bale rubber piece with accurate dimensions.
According to a bale rubber holding device of an embodiment, there is provided a bale rubber holding device which is provided in a feeding device which feeds a bale rubber, which is a lump of rubber, forward toward a cutting position, where the bale rubber holding device grips a rear portion of the bale rubber.
According to a method for cutting a bale rubber of an embodiment, there is provided a method for cutting a bale rubber which includes feeding the bale rubber forward toward a cutting position and cutting the bale rubber at the cutting position, where at least while the bale rubber is cut, a bale rubber holding device provided in a feeding device which feeds the bale rubber grips a rear portion of the bale rubber.
According to the embodiment, it becomes easy to cut out a bale rubber piece with accurate dimensions.
An embodiment will be described with reference to the drawings. The embodiment described below is merely an example and those which are appropriately modified without departing from a spirit of the present invention shall be included in a scope of the present invention.
1. Overall Configuration of Cutting Device
As illustrated in
The preparation conveyor 11 is a belt conveyor. A bale rubber 20 is arranged on the preparation conveyor 11. The bale rubber 20 is a mass of rubber as a raw material for a tire, is substantially rectangular parallelepiped shape, and is packaged with a resin sheet (not illustrated). The preparation conveyor 11 rotates in a direction of moving the bale rubber 20 on the preparation conveyor 11 toward the first measurement conveyor 12. The preparation conveyor 11 is rotated by being driven by a motor 35 (see
The first measurement conveyor 12 is a roller conveyor composed of a plurality of rollers 30. The roller 30 can rotate in a direction of moving the bale rubber 20 which has moved from the preparation conveyor 11 to the constant-rate feed conveyor 13. The roller 30 is rotated by being driven by a motor 36 (see
The constant-rate feed conveyor 13 is a roller conveyor including a plurality of rollers 31. The roller 31 is a rotatable free roller and can rotate in a direction orthogonal to the rotation direction of the roller 30 of the first measurement conveyor 12.
A snap cover chain 23 which moves up and down with respect to the constant-rate feed conveyor 13 is provided. The snap cover chain 23 is an endless chain which rotates in the same direction as a transport direction of the first measurement conveyor 12 when driven by a motor 24 (see
A feeding device 50 is provided on the constant-rate feed conveyor 13. The feeding device 50 includes a cylinder 51 which operates with liquid or gas and a plate-shaped push plate 52 attached to a tip of a rod of the cylinder 51. The push plate 52 is provided with a bale rubber holding device 54 (see
A servomotor may be used instead of the cylinder 51 as a device for moving the push plate 52.
A length measuring sensor 53 is provided on the push plate 52. When a first cutter 40, which will be described below, of the cutting portion 18 is lowered, the length measuring sensor 53 can measure a distance from the push plate 52 to the first cutter 40.
The cutting portion 18 is a portion which cuts the bale rubber 20 sent from the constant-rate feed conveyor 13 into a bale rubber piece 22. As will be described below, the cutting portion 18 is provided with the first cutter 40 which descends toward the bale rubber 20 and a second cutter 41 which rises toward the bale rubber 20.
The discharge conveyor 19 is a belt conveyor. The discharge conveyor 19 can rotate in the same direction as the rollers 31 of the constant-rate feed conveyor 13. The discharge conveyor 19 is rotated by being driven by a motor 33 (see
The discharge conveyor 19 may be composed of a plurality of free rollers. Instead of the discharge conveyor 19, a sliding plate inclined with respect to a horizontal plane may be used.
The second measurement conveyor 16 is a belt conveyor. The second measurement conveyor 16 can rotate in a direction parallel to the preparation conveyor 11 and the first measurement conveyor 12. The second measurement conveyor 16 is rotated by being driven by a motor 37 (see
The defective product box 17 is arranged on one side of a rotation direction of the second measurement conveyor 16 and the non-defective product transport conveyor 15 and the non-defective product box 14 are arranged on the other side. The second measurement conveyor 16 is provided on a second weight sensor 39 (see
The non-defective product transport conveyor 15 is a belt conveyor. The non-defective product transport conveyor 15 transports the bale rubber piece 22 sent from the second measurement conveyor 16 to the non-defective product box 14. The non-defective product transport conveyor 15 is rotated by being driven by a motor 32 (see
As illustrated in
The first weight sensor 38, the second weight sensor 39, the length measuring sensor 53, motors 24, 32, 35, 36, and 37, cylinders 42, 46, 47, 48, and 51, and the like are connected to the control unit 25. An input device 28 for inputting manufacturing conditions and the like to the control unit 25 is also connected to the control unit 25. The control unit 25 controls the motors 24, 32, 35, 36, and 37, the cylinders 42, 46, 47, 48, 51, and 60, and the like based on measured values of the connected sensors and input values from the input device 28.
2. Configuration of Bale Rubber Holding Device
As illustrated in
A horizontal plate-shaped extension portion 57 is provided to extend from the movable portion 55 toward a back side (the side opposite to the front side in a feeding direction) of the push plate 52. The extension portion 57 is extended to a position beyond a center in the width direction of the push plate 52 on the back side of the push plate 52. An elongated hole 58 is formed in a vicinity of the center of the push plate 52 in the width direction to penetrate the extension portion 57 in the up-down direction. The elongated hole 58 extends in an extension direction of the extension portion 57.
The bale rubber holding device 54 further includes a cylinder 60 fixed by a fixing member 59 to the back surface of the push plate 52 and a rod member 62 provided at a tip of a rod 61 of the cylinder 60. The rod member 62 is a single rod-shaped member extending in the up-down direction. The rod member 62 vertically penetrates the elongated holes 58 of the left and right extension portions 57.
On the left and right sides of the back surface of the push plate 52, shaft member holding portions 63 projecting rearward are provided. On both the left and right sides, the shaft member holding portions 63 respectively hold shaft members 64 extending in the up-down direction.
The shaft members 64 on both the left and right sides respectively penetrate holes 66 (see
In such a bale rubber holding device 54, when the cylinder 60 advances the rod 61 forward (lower side in
When the cylinder 60 moves the rod 61 backward (upper side in
When the bale rubber 20 contacts the front surface of the push plate 52, if the claw 56 advances toward the center of the push plate 52 in the width direction, as illustrated in
On the back surface of the push plate 52, a mounting portion 65 to which the rod of the above-described cylinder 51 is mounted is provided. The push plate 52 and the bale rubber holding device 54 are integrally sent out by the cylinder 51.
3. Configuration of Cutting Portion
As illustrated in
The first cutter 40 can be moved up and down by the cylinder 42 (see
As a part of the cutting portion 18, a first arrangement member 43 is provided between the constant-rate feed conveyor 13 and the first cutter 40 and a second arrangement member 44 is provided between the second cutter 41 and the discharge conveyor 19. An upper surface of the first arrangement member 43 and an upper surface of the second arrangement member 44 are on the same surface as an upper surface of the constant-rate feed conveyor 13. A portion from the upper surface of the first arrangement member 43 to the upper surface of the second arrangement member 44 is a cutting position arranged when the bale rubber 20 is cut.
The first arrangement member 43 is provided with a cutter receiving portion 45 to which a cutting edge of the first cutter 40 descending from above contacts. The cutter receiving portion 45 is formed as an inclined surface along the cutting edge of the first cutter 40. The cutter receiving portion 45 can be displaced in a width direction of the first cutter 40 by the cylinder 47 (see
The first cutter 40 descends until it contacts the cutter receiving portion 45. Therefore, the first cutter 40 cuts the bale rubber 20 from an upper end to a lower end. On the other hand, the second cutter 41 rises to a position slightly above the upper surface of the second arrangement member 44. Then, the lowering of the first cutter 40 and the ascending of the second cutter 41 are performed in synchronization, but the second cutter 41 supports the bale rubber 20 from below while the first cutter 40 cuts the bale rubber 20.
4. Manufacturing Method of Bale Rubber Piece by Cutting Device
First, manufacturing conditions are input from the input device 28 to the control unit 25. The manufacturing conditions are the number of times one bale rubber 20 is cut, a target weight wt of the bale rubber piece 22, and the like. The input may be performed manually by an operator, or may be performed by an imaging unit (not illustrated) reading a work instruction sheet or the like.
Next, the bale rubber 20 wrapped in a resin sheet (not illustrated) is placed on the preparation conveyor 11. The control unit 25, which detects that the bale rubber 20 is placed, drives the motor 35 to rotate the preparation conveyor 11 and drives the motor 36 to rotate the first: measurement conveyor 12, in such a manner that the bale rubber 20 is transported to the center of the first measurement conveyor 12.
When the control unit 25 detects that the bale rubber 20 reached the center of the first measurement conveyor 12, the first weight sensor 38 measures a weight W of the bale rubber 20. The measured weight W is stored in the storage unit in the control unit 25.
The control unit 25 then controls the cylinder 48 to raise the snap cover chain 23 above the roller 31 of the constant-rate feed conveyor 13. Next, the control unit 25 drives the motors 36 and 24 to rotate the first measurement conveyor 12 and the snap cover chain 23. As a result, as illustrated in
Next, the control unit 25 controls the cylinder 51 to move the push plate 52 of the feeding device 50 toward the bale rubber 20 at the predetermined position and stop the push plate 52 at a position where the push plate 52 comes into contact with the bale rubber 20. Here, the movable portion 55 (not illustrated in
Next, the control unit 25 controls the cylinder 60 and closes the movable portion 55. Then, as illustrated in
Next, the control unit 25 controls the cylinder 42 to lower the first cutter 40 until the first cutter 40 contacts the cutter receiving portion 45 (see
As illustrated in
Next, the control unit 25 measures a distance L from the push plate 52 of the feeding device 50 to the first cutter 40 with the length measuring sensor 53. The distance L measured here coincides with the length of the bale rubber 20 in the feeding direction to the cutting portion 18. The measured distance (length of bale rubber 20) L is stored in the storage unit 26 of the control unit 25.
Next, as illustrated in
Next, as illustrated in
At the same time that the lowered first cutter 40 contacts the cutter receiving portion 45, or after the lowered first cutter 40 contacts the cutter receiving portion 45, the control unit 25 controls the cylinder 47 to displace the cutter receiving portion 45 in the width direction (left-right direction) of the first cutter 40. As a result, even when the lower end of the bale rubber 20 and the resin sheet wrapping the bale rubber 20 remain uncut, the remaining portion is torn off between the first cutter 40 and the cutter receiving portion 45.
The second cutter 41 may be displaced in the width direction (left-right direction) of the second cutter 41 while rising or after being raised due to cutting of the bale rubber 20.
The bale rubber piece 22 made by such cutting is transported to the second measurement conveyor 16 by the discharge conveyor 19. When the control unit 25 detects that the bale rubber piece 22 has reached the second measurement conveyor 16, the control unit 25 measures the weight wn (wn is the weight of the n-th bale rubber piece 22, and in the case of the first one as here, n=1) of the bale rubber piece 22 with the second weight sensor 39. The measured weight wn of the bale rubber piece 22 is stored in the storage unit 26 of the control unit 25.
When the weight of the bale rubber piece 22 meets acceptance criteria, the control unit 25 controls the motor 37 to rotate the second measurement conveyor 16 and transports the bale rubber piece 22 to the non-defective product box 14. On the other hand, when the weight of bale rubber piece 22 does not meet the acceptance criteria, the control unit 25 controls the motor 37 to rotate the second measurement conveyor 16 and transports the bale rubber piece 22 to the defective product box 17.
The control unit 25 sends out the bale rubber 20 again by the feeding device 50 after the first cutting of the bale rubber 20 and performs the second cutting. The control unit 25 repeats feeding by the feeding device 50 and cutting by the first cutter 40 until the entire bale rubber 20 is divided into a plurality of bale rubber pieces 22. The second and subsequent feed distance Sn by the feeding device 50 will be described below.
The bale rubber holding device 54 continues to grip the rear end portion of the bale rubber 20 until the final cutting of the bale rubber 20 is completed. After the final cutting of the bale rubber 20, the control unit 25 opens the movable portion 55 of the bale rubber holding device 54 to release the remaining bale rubber 20 (that is, the last bale rubber piece 22) from the bale rubber holding device 54. Then, the control unit 25 pushes the last bale rubber piece 22 to the discharge conveyor 19 with the push plate 52.
5. Method for Determining Feed Amount of Bale Rubber
Here, a method for determining the feed distance Sn of the bale rubber 20 by the feeding device 50 will be described based on a flowchart of
First, as described above, the first weight sensor 38 measures the weight W of the bale rubber 20 before cutting on the first measurement conveyor 12 (ST1). The measured weight W is stored in the storage unit 26 of the control unit 25.
Next, as described above, the length measuring sensor 53 measures the length L of the bale rubber 20 before cutting pressed against the first cutter 40 by the feeding device 50 (ST2). The measured length L is stored in the storage unit 26 of the control unit 25.
The calculation unit 27 of the control unit 25 calculates a first feed amount (feed distance) S1 of the bale rubber 20 by the feeding device 50 after measuring the length L of the bale rubber 20 (ST3). The feed distance S1 is calculated by the following equation so that when the length of the bale rubber piece 22 becomes S1, the weight of the bale rubber piece 22 becomes a target weight wt. The target weight wt of the bale rubber piece 22 is stored in the storage unit 26 in advance by an operator.
S
1
=w
t
×L/W [Equation 1]
Next, the control unit 25 controls the feeding device 50 and sends the bale rubber 20 forward (in a direction of the first cutter 40) by the obtained distance S1 (ST4). Next, the control unit 25 controls the first cutter 40 and the second cutter 41 to cut the bale rubber 20 and cut out the bale rubber piece 22 having a length S1 (ST5).
Next, as described above, the second weight sensor 39 provided on the second measurement conveyor 16 measures a weight w1 of the cut-out bale rubber piece 22 (ST6). The measured weight w1 is stored in the storage unit 26 of the control unit 25.
Next, the control unit 25 determines whether the entire bale rubber 20 is divided into the bale rubber pieces 22 (ST7).
For example, a sensor detects the amount of the bale rubber 20 remaining further on the feeding device 50 side than the first cutter 40. When the detected amount is equal to or more than a predetermined amount, it is determined that the division is not completed, and when the detected amount is less than the predetermined amount, it is determined that the division is completed.
Alternatively, the number of cuts required to divide the entire bale rubber 20 into the bale rubber piece 22 is set in advance in the control unit 25. The control unit 25 determines that the division of the bale rubber 20 is not completed when the cutting of the set number of cuts is not completed. When the cutting of the set number of cuts is completed, it is determined that the division of the bale rubber 20 is completed.
Anyway, when the control unit 25 determines that the division of the bale rubber 20 is not completed (No in ST7), the control unit 25 proceeds to a next step (ST8, ST9). On the other hand, when the control unit 25 determines that the division of the bale rubber 20 is completed (Yes in ST7), the control unit 25 ends the above flow.
In the present embodiment, it is assumed that the bale rubber 20 is cut 10 to 15 times. Therefore, when the above-described first cutting is completed, the control unit 25 determines that the division of the bale rubber 20 is not completed (No in ST7). Therefore, the flow proceeds to the next step (ST8, ST9).
In the next step (ST8, ST9), the calculation unit 27 calculates a distance S2 of second feeding of the bale rubber 20 so that a weight w2 of the bale rubber piece 22 cut out the second time can be brought closer to the target weight wt. Specifically, the calculation unit 27 calculates the distance S2 of the second feeding by the following equation using the weight w1 of the bale rubber piece 22 cut out immediately before.
That is, although a cross-sectional area (area in a plane orthogonal to the feeding direction) of the bale rubber 20 changes depending on the location, it is assumed that the cross-sectional area is approximately the same at the location of the bale rubber piece 22 cut out the first time and the location of the bale rubber piece 22 cut out the second time. Based on the assumption, it can be said that the weight per unit length of the bale rubber piece 22 cut out the second time matches the weight w1/S1 per unit length of the bale rubber piece 22 cut out the first time. Therefore, the target weight wt of the bale rubber piece 22 is divided by the weight w1/S1 per unit length of the bale rubber piece 22 to determine the distance S2 for the second feeding.
When the distance S2 for the second feeding is determined, the process returns to a step (ST4) of feeding the bale rubber 20 and the feeding device 50 feeds the bale rubber 20 by the distance S2. The first cutter 40 cuts out the second bale rubber piece 22 and the weight w2 of the bale rubber piece 22 is measured by the second weight sensor 39.
After that, the control unit 25 repeats the routine after ST4 until it is determined that the division of the bale rubber 20 is completed (Yes in ST7). In the routine, the (n+1)-th feed distance Sn+1 of the bale rubber 20 is calculated by the following generalized equation using the n-th feed distance Sn and the weight wn of the bale rubber piece 22 cut out at the n-th time.
6. Effect of Embodiment
As described above, the bale rubber holding device 54 of the present embodiment can grip the rear portion of the bale rubber 20. Therefore, it is possible to prevent the bale rubber 20 from being displaced when the bale rubber 20 is cut, and thus it becomes easy to cut out the bale rubber piece 22 with accurate dimensions.
Here, since the bale rubber holding device 54 grips the rear portion of the bale rubber 20 by interposing it from two directions, the bale rubber 20 can be firmly gripped. Since the bale rubber holding device 54 includes the claw 56 which bites into the bale rubber 20, the bale rubber 20 can be firmly gripped.
In the embodiment, the bale rubber holding device 54 continues to grip the rear portion of the bale rubber 20 while the bale rubber 20 is cut by the first cutter 40 (that is, during one cutting operation by the first cutter 40). Therefore, it is possible to prevent the bale rubber 20 from being displaced during cutting.
In the embodiment, the bale rubber holding device 54 continues to grip the rear portion of the bale rubber 20 while the bale rubber 20 is cut by the first cutter 40 a plurality of times. Therefore, it is possible to prevent the bale rubber 20 from being displaced between the first cutting and the second cutting.
7. Modification Example
Various modifications can be made to the embodiment described above.
For example, as a bale rubber holding device, various devices capable of gripping the rear portion of the bale rubber 20 can be applied.
A bale rubber holding device 154 shown in
The bale rubber holding device 154 is provided for a push plate 152 corresponding to the push plate 52 in the embodiment described above. A rib 166 extending in the up-down direction is fixed to one (left side in the case of
On the other side (on the right side in the case of
Three large claws 156 arranged in the up-down direction are provided on a front surface of the movable portion 155. The large claws 156 project forward from the notch 168 of the push plate 152. The large claws 156 are curved toward the center in the left-right direction (width direction) of the push plate 152 and the tips thereof are sharpened.
In such a bale rubber holding device 154, when the cylinder 160 moves the movable portion 155 away from the small claw 167, a distance from a tip of the large claw 156 provided in the movable portion 155 to a tip of the small claw 167 is wider than a width of the bale rubber 20.
Here, the bale rubber 20 is arranged between the tip of the large claw 156 and the tip of the small claw 167. Next, the cylinder 160 moves the movable portion 155 closer to the small claw 167. As a result, the distance from the tip of the large claw 156 to the tip of the small claw 167 becomes narrower than the width of the bale rubber 20 and the large claw 156 and the small claw 167 bite into the bale rubber 20. The large claw 156 and the small claw 167 can grip the rear portion of the bale rubber 20 from two directions.
Number | Date | Country | Kind |
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2020-170181 | Oct 2020 | JP | national |