EP0421803A1

EP0421803A1 - Weft unthreaded textile coating method and apparatus

Info

Publication number: EP0421803A1
Application number: EP90310921A
Authority: EP
Inventors: Norio Miyake; Mitsushige Kuroiwa; Kazuhiko Yoshitake; Kazunari Ikeda
Original assignee: Bridgestone Corp
Current assignee: Bridgestone Corp
Priority date: 1989-10-04
Filing date: 1990-10-04
Publication date: 1991-04-10
Also published as: JPH03124868A

Abstract

A coating apparatus for weft unthreaded textiles includes a deep grooved roll (20) to receive warps (C) of a weft unthreaded textile (S), and a shallow grooved roll (33) arranged downstream of said deep grooved roll to receive the warps arranged by the deep grooved roll. The apparatus further includes press-fitting means (46) for pressing the grooved roll (33) against a rubber sheet (6) on a calender roll (2) to force the warps in the shallow grooves into the rubber sheet, a restraining roll (52) rotatably arranged between the deep grooved roll and the shallow grooved roll and able to be in contact with a surface of the weft unthreaded textile, and urging means (54) for urging the restraining roll in a direction perpendicular to a surface of the weft unthreaded textile to change the moving direction of the weft unthreaded textile, thereby increasing a winding angle of the warps around the grooved roll (33) and preventing untwisting of the warps.

Description

This invention relates to a coating method and a coating apparatus for weft unthreaded textiles.
The term "weft unthreaded textile" used herein is intended to designate a textile whose wefts have been cut and removed to have only warps.
In tire industries, in general, plies for constituting a tire are reinforced by cords. Hitherto, textiles having a number of thick warps and thin wefts entangling and connecting the warps have been used as such reinforcing cords in order to improve the tire production efficiency.
However, if such textiles as the reinforcing cords are used as they are, the wefts remain in tires. Therefore, the wefts and warps are rubbed each other to be worn off in running of tires to lower the performance of the tires. In coating the textile with rubber, the warps are affected by the wefts to be irregularly moved or staggered. In order to assure required dimensions between plies, therefore, coating rubbers must be unavoidably made thicker. For the purpose of solving these problems in the tire industries, after wefts of textiles have been cut and removed, the textiles without wefts are coated with rubbers.
Hitherto, in applying rubber coating to such a textile having no wefts according to a conventional method, warps of the textile are first inserted into a number of deep grooves formed in an outer circumference of a deep grooved roll, respectively, so as to individually guide and exactly arrange the warps. Thereafter, the arranged warps of the textile are fed through a predetermined distance, for example, of the order of 300 mm in a longitudinal direction of the textile. The warps of the textile are then supplied between a rubber sheet on a press roll and another rubber sheet on a calender roll so that the textile is coated with the rubber sheets.
In such a rubber coating method, the deep grooved roll is arranged fairly remote from the calender roll. With this arrangement, even if some warps jump out of the deep grooves of the deep grooved roll due to knots or knuckles of the warps or residues of a dipping solution adhered thereto, the warps can be readily returned into the predetermined deep grooves. However, the fact that the deep grooved roll is arranged remote from the calender roll encounters a difficulty in that flowing of rubber in coating causes the warps to be displaced in width directions of the textile to disturb pitches of the warps.
In such a rubber coating method, moreover, a clearance between the press roll and the calender roll is maintained constant, and the warps of the textile are supplied between the rubber sheets on the press roll and the calender roll to press the warps to the rubber sheets. Therefore, depths of the warps forced into the rubber sheets are insufficient. As a result, clearances are likely to occur between the first coated rubber sheet and a second rubber sheet coated on the opposite surfaces of the textile, respectively. There is, therefore, a risk of the rubber sheets separating from each other at least locally in latter processes.
Moreover, the textile having no wefts is directly supplied from the deep grooved roll to the press roll. Therefore, a winding angle of the textile around the press roll is relatively small, and the warps of the textile are apt to untwist on the press roll. As a result, warps are readily displaced in an axial directions of the deep grooved roll or the press roll to cause disturbances in pitch of the warps of the textile.
It is an object of the invention to provide a coating method and a coating apparatus for weft unthreaded textiles, which are able to effectively prevent any disturbance in pitch of warps of textiles and able to firmly applying rubber coating to the warps in a reliable manner.
In order to accomplish this object, a coating method for weft unthreaded textiles according to the invention comprises steps of arranging warps of a weft unthreaded textile being fed in its longitudinal direction by individually guiding the warps without disturbing their pitches by a deep grooved roll, press-fitting the arranged warps of the weft unthreaded textile into a rubber sheet on a calender roll by forcing the warps into the rubber sheet by a grooved roll which guides to arrange the warps again without disturbing their pitches, and between the first arranging step and the press-fitting step, urging the weft unthreaded textile in a direction perpendicular to a surface of the weft unthreaded textile by a restraining roll to change a moving direction of the weft unthreaded textile, thereby increasing a winding angle of the warps around the grooved roll and preventing untwisting of the warps.
In another aspect of the invention, a coating apparatus for weft unthreaded textiles comprises a deep roll formed in an outer circumference with a number of deep grooves spaced in its axial direction predetermined distances and rotatable about its axis to insert warps of a weft unthreaded textile being fed in its longitudinal direction into said deep grooves to individually guide and arrange the warps without disturbing their pitches, a grooved roll arranged downstream of said deep grooved roll with respect to a flow of the weft unthreaded textile, said grooved roll being formed in an outer circumference with a number of shallow grooves spaced in its axial direction predetermined distances and rotatable about its axis to insert the warps arranged by the deep grooved roll into said shallow grooves to individually guide and arrange the warps again without disturbing their pitches, press-fitting means for pressing the grooved roll against a rubber sheet on a calender roll to force the warps in the shallow grooves into the rubber sheet, a restraining roll rotatably arranged between said deep grooved roll and said grooved roll and able to be in contact with a surface of the weft unthreaded textile, and urging means for urging the restraining roll in a direction perpendicular to a surface of the weft unthreaded textile to change a moving direction of the weft unthreaded textile, thereby increasing a winding angle of the warps around the grooved roll and preventing untwisting of the warps.
It is now assumed that a weft unthreaded textile is being fed in its longitudinal direction toward the calender roll. On its way thereto, the weft unthreaded textile passes over the deep grooved roll, when warps of the textile are inserted into the number of deep grooves formed in the outer circumference of the deep grooved roll spaced predetermined distances in its longitudinal direction, whereby the warps are individually guided and exactly arranged without disturbing their pitches. As the warps of the weft unthreaded textile are securely arranged with exact intervals or pitches with the aid of the deep grooves in this manner, the warps are stably fed to the grooved roll under the exactly arranged condition.
The warps are then fed to the grooved roll where the warps are inserted into the number of grooves formed in the outer circumference of the shallow grooved roll spaced predetermined distances in its longitudinal direction, whereby the warps are individually guided and exactly arranged again without disturbing their pitches. The warps in the shallow grooves are forced into the rubber sheet on the calender roll by pressing the grooved roll against the rubber sheet by means of press-fitting means. In such a process, as the warps of the weft unthreaded textile are settled in the shallow grooves of the grooved roll pressed against the rubber sheet in this manner, there is no longer any risk of the warps jumping out of the shallow grooves and moving in axial directions of the grooved roll, even if there are knots or knuckles of the warps or residues of a dipping solution or if the warps are affected by flows of the rubber in the rubber sheet on being coated with the rubber. Therefore, pitches or distances between the warps are effectively maintained without being disturbed.
Moreover, the grooved roll is urged against the rubber sheet, so that the warps of the weft unthreaded textile are forced into the rubber sheet. As a result, the warps penetrate into the rubber sheet to sufficient depths thereof. Therefore, there is no risk of any clearances occurring between the rubber sheets coated on both surfaces of the weft unthreaded textile and there is no risk of these rubber sheets separating from each other in latter processes.
In this case, the weft unthreaded textile between the deep grooved roll and the grooved roll is depressed downwardly in the direction perpendicular to the surface of the weft unthreaded textile by means of the restraining roll. As a result, the feeding direction of the weft unthreaded textile is changed to increase the winding angle of the warps around the grooved roll so as to increase contact lengths of the warps with the grooved roll. Therefore, pitches or distances between the warps are maintained without being disturbed. Moreover, as the warps of the weft unthreaded textile are urged by the restraining roll, the warps are effectively prevented from untwisting on the grooved roll. Therefore, the disturbance in pitch of the warps is prevented more effectively.
The invention will be more fully understood by referring to the following detailed specification and claims taken in connection with the appended drawings.

Fig. 1 is a partially removed front elevation illustrating one embodiment of the apparatus according to the invention;
Fig. 2 is a partially removed fragmentary elevation viewed in directions shown by arrows II in Fig. 1;
Fig. 3 is a partially removed front elevation illustrating the proximity of the grooved roll used in the apparatus according to the invention;
Fig. 4 is a sectional view taken along the lines IV-IV in Fig. 1;
Fig. 5 is a partial elevation viewed in directions shown by arrows V in Fig. 1;
Fig. 6 is a graph illustrating disturbances in pitch of warps of a weft unthreaded textile coated by a method of the prior art; and
Fig. 7 is a graph illustrating slight disturbances in pitch of warps of a weft unthreaded textile coated according to the invention.

Referring to Fig. 1, a calender unit 1 includes two pairs of calender rolls 2, 3, 4 and 5 driven by a driving mechanism (not shown). One pair of the calender rolls 2 and 3 are rotated in directions shown by arrows to form a rubber sheet 6 having a predetermined thickness, while the other pair of the calender rolls 4 and 5 are rotated in directions shown by other arrows to form a rubber sheet 7 having a predetermined thickness. These rubber sheets 6 and 7 attached to circumferences of the calender rolls 2 and 4, respectively, are transferred by rotations of these rolls 2 and 4. While doing so, these rubber sheets 6 and 7 pass between the calender rolls 2 and 4 to be joined with each other.
A frame 11 is arranged rearward of the calender unit 1 for rotatably supporting a plurality of guide rollers 12, 13 and 14. A weft unthreaded textile S whose wefts have been cut and removed is supplied to these guide rollers 12, 13 and 14 from the rearward or the right hand of the drawing, Fig. 1 to the forward. The weft unthreaded textile S is fed in its longitudinal direction being guided by the guide rollers 12, 13 and 14 so that the textile S approaches the calender unit 1.
The frame 11 supports a lifter member 17 adapted to be raised and lowered by actuating a motor 18. As shown in Figs. 1 and 2, a deep grooved roll 20 extending in a width direction of the weft unthreaded textile S is rotatably supported by an upper end of the lifter member 17 through a bracket 19. The deep grooved roll 20 is formed in its outer circumference with a number (equal to the number of warps C of the textile S in this embodiment) of deep grooves 21 spaced in longitudinal directions of the roll 20 from each other equal distances equal to intervals (pitches) between the warps of the weft unthreaded textile S in this embodiment. The deep grooves 21 extend in a circumferential direction of the roll 20 and are deeper than diameters of the warps C of the textile S. The warps C of the weft unthreaded textile S are inserted into the deep grooves 21 so as to be individually guided by the deep grooves 21 so that the warps C are exactly arranged without any disturbance in pitch.
Referring to Figs. 1 and 3, to the frame 11 is fixed an inclined beam 26 extending from the forward to the rearward. The inclined beam 26 is inclined progressively raising as forwardly advancing or approaching the calender unit 1. A screw shaft 27 is rotatably supported with its forward and rearward ends by the inclined beam 26 so that the screw shaft 27 extends along the inclined beam 26. The screw shaft 27 is rotated about its axis by a motor 28 fixed to an upper surface of a rear end of the inclined beam 26. Guide rails 29 are provided on the inclined beam 26 immediately below the the screw shaft 27. Slide bearings 31 are adapted to slidably engage the guide rails 29 and fixed to a carriage 30 into which the screw shaft 27 is threadedly engaged.
The carriage 30 is provided with a support portion 32 for supporting both ends of a grooved roll 33 extending in the width direction of the weft unthreaded textile S and located thereabove. When the carriage 30 is moved in longitudinal directions of the inclined beam 26 by rotation of the screw shaft 27, the grooved roll 33 is moved between a press-fitting position A shown in solid lines in Fig. 1 nearest to the calender unit 1 and an exchange position B shown in phantom lines remotest from the calender unit 1. The grooved roll 33 at the position A forms a slight clearance with the guide roll 2 therebetween.
The grooved roll 33 is formed in an outer circumference of an axially center portion with a number of shallow grooves 35 axially equally spaced in a similar manner to those of the deep grooved roll 20. Depths of these shallow grooves 35 are less than the diameters of the warps C which are individually inserted into the shallow grooves 35 with parts of the warps C extending somewhat out of the shallow grooves 35. Upon inserting the warps C into the shallow grooves 35, the warps C are individually guided by the shallow grooves so as to be exactly located again.
Referring to Figs. 1, 4 and 5, a pair of cylinders 38 having piston rods 39 are mounted on the frame 11, respectively, and to rod ends of the piston rods 39 is secured a connecting plate 40 extending in the width directions of the weft unthreaded textile S. Guide blocks 41 are fixed to the frame 11 on lateral sides of the cylinders 38, respectively. Guide rods 42 are slidably inserted into the guide blocks 41, respectively, and forward ends of the guide rods 42 are fixed to the connecting plate 40, respectively. To a forward surface of the connecting plate 40 are fixed urging pawls 43, respectively, which are formed with engaging recesses 45 adapted to engage engaging portions 44 provided at both ends of the grooved roll 33.
When the grooved roll 33 is at the press-fitting position A and the cylinders 38 are actuated to extend the piston rods 39, the urging pawls 43 are moved toward the calender roll 2 to cause the grooved rolls 33 to press against the rubber sheet 6 on the calender roll 2. Therefore, the wraps C in the respective shallow grooves 35 of the grooved roll 33 are forced into the rubber sheet 6 to predetermined depths. The cylinders 38, the connecting plate 40, the guide rods 42 and urging pawls 43 form as a whole press-fitting means 46 for forcing the warps C of the weft unthreaded textile S in the shallow grooves 35 into the rubber sheet 6 by pressing the grooved roll 33 against the rubber sheet 6 on the calender roll 2.
As shown in Fig. 1, between the deep grooved roll 20 and the grooved roll 33 is provided the lifter 50 whose lower end rotatably supports through a bracket 51 a restraining roll 52 extending in the width direction of the weft unthreaded textile S and adapted to be in rolling contact with the textile S. A screw shaft 53 extends in a vertical direction and has a lower end threadedly engaged in the lifter 50. The screw shaft 53 is rotated about its axis by a motor (not shown) to raise or lower the lifter 50.
The lifter 50, the screw shaft 53 and the motor (not shown) form as a whole urging means 54 for urging the restraining roll 52 in a direction perpendicular to a surface of the weft unthreaded textile S. When the weft unthreaded textile S between the deep grooved roll 20 and the grooved roll 33 is urged downwardly by means of the restraining roll 52, the weft unthreaded textile S is fed in an L-shaped passage having a large obtuse angle as shown in Fig. 1. Therefore, a winding angle of the warps C around the grooved roll 33 is increased and the warps C are prevented from untwisting.
A cylinder 58 is fixed to the frame 11 at a position immediately below the grooved roll 33 positioned at the exchange position B. To a rod end of a piston rod 59 of the cylinder 58 is fixed through a bracket 61 a receiving member 60 of a V-shaped section and extending along the grooved roll 33. When the cylinder 58 is actuated to extend the piston rod 59, the receiving member 60 rises to support a center portion of the grooved roll 33 and raise the grooved roll 33, with the result that the grooved roll 33 is transferred from the support portion 32 to the receiving member 60. The cylinder 58 and the receiving member 60 form as a whole exchange means 62 for exchanging grooved rolls 33.
The operation of the embodiment of the apparatus according to the invention will be explained hereinafter.
In case that both surfaces of a weft unthreaded textile S are coated with rubbers by means of the coating apparatus as above described, first the restraining roll 52 is retracted upwardly shown in phantom lines in Fig. 1 and then the weft unthreaded textile S extends around the guide rollers 12, 13 and 14. Thereafter, leading ends of warps C of the textile S are inserted into the respective shallow grooves 35 of the grooved roll 33. The cylinders 38 of the press-fitting means are then actuated so as to extend the piston rods 39 to urge the grooved roll 33 against a rubber sheet 6 on the calender roll 2, thereby embracing the leading ends of the warps C between the grooved roll 33 and the rubber sheet 6.
Under this condition, the screw shaft 53 is rotated to lower the restraining roll 52 from the position shown in phantom lines in Fig. 1 to the position shown in solid lines, so that the weft unthreaded textile S between the guide roller 14 and the grooved roll 33 is urged downwardly to form an L-shaped passage of the weft unthreaded textile S. At this time, the warps C of the weft unthreaded textile S are inserted into the deep grooves 21 of the deep grooved roll 20, respectively.
The calender unit 1 is then actuated to rotate the calender rolls 2, 3, 4 and 5 in the directions shown by the respective arrows to form rubber sheets 6 and 7. At this moment, the weft unthreaded textile S has been embraced on both side by the calender roll 2 and the grooved roll 33. Therefore, the weft unthreaded textile is driven from the rearward to the forward by the rotations of the calender roll 2 and the grooved roll 33.
As above described, first the weft unthreaded textile S passes over the deep grooved roll 20 so that warps C of the weft unthreaded textile S are inserted into the deep grooves 21 of the deep grooved roll 20, respectively. Therefore, the warps C are individually guided and exactly located by the deep grooves 21.
As the warps C of the weft unthreaded textile S are thus exactly located without disturbing their pitches in a reliable manner by means of the deep grooves 21, the warps C are stably fed to the grooved roll 33 under the exactly located condition.
After the warps C have contacted the restraining roll 52, they arrive at the grooved roll 33 where the warps C are inserted into the shallow grooves 35 of the grooved roll 33, respectively. Therefore, the warps C are again individually guided and exactly located without disturbing their pitches by the shallow grooves. In this case, as the grooved roll 33 is pressed against the rubber sheet 6 on the calender roll 2 by means of the press-fitting means 46, the warps C are forced into the rubber sheet 6.
The warps C of the weft unthreaded textile S are settled in the shallow grooves 35 of the grooved roll 33 being pressed against the rubber sheet 6 in this manner. Therefore, there is no longer any risk of the warps C jumping out of the shallow grooves 35 and moving in axial directions of the grooved roll 33, even if there are knots or knuckles of the warps C or residues of a dipping solution or if the warps C are affected by flows of the rubber in the rubber sheet 6 on being coated with the rubber. As a result, pitches or distances between the warps C are effectively maintained without being disturbed. Moreover, the grooved roll 33 is urged against the rubber sheet 6, so that the warps C of the weft unthreaded textile S are forced into the rubber sheet 6. Therefore, the warps C penetrate into the rubber sheet 6 to sufficient depths thereof.
It should be noticed that when the weft unthreaded textile S is being fed from the deep grooved roll 20 to the grooved roll 33, it becomes in contact with the tension roll 52 to be depressed downwardly into the L-shaped passage as above described. As a result, the winding angle of the warps C around the grooved roll 33 becomes large to increase contact lengths of the warps C with the grooved roll 33. Therefore, the warps C are prevented from moving on the grooved roll 33 in its axial directions so that pitches or distances between the warps C are properly maintained. Moreover, as the warps C of the weft unthreaded textile S are urged by the tension roll 52, the warps C are effectively prevented from untwisting on the grooved roll 33. Therefore, any disturbance in pitch of the warps C is prevented more effectively.
The rubber sheet 6 including the weft unthreaded textile S therein is transferred to somewhere between the calender rolls 2 and 4 by the rotation of the calender roll 2. On the other hand, the rubber sheet 7 is also transferred to somewhere between the calender rolls 2 and 4 by the rotation of the calender roll 4. When the rubber sheet 7 is passing between the calender rolls 2 and 4, the rubber sheet 7 is pressed against an uncoated surface of the weft unthread textile S to perform a coating the textile S by the rubber sheet 7, while the rubber sheet 7 unites with the rubber sheet 6 to be joined with each other.
In this case, as the warps C of the weft unthreaded textile S have been positioned at sufficient depths in the rubber sheet 6, there is no risk of any clearances occurring between the rubber sheets 6 and 7 coated on both surfaces of the weft unthreaded textile S and there is no risk of these rubber sheets 6 and 7 separating from each other in any later process.
Figs. 6 and 7 illustrate results of measuring irregularities in pitch of warps C of weft unthreaded textiles S coated with rubber by methods of the prior art and the present invention, respectively. As shown in Fig. 6, pitches of the warps C according to the prior art are disturbed on both sides of a set pitch of 0.85 mm to a great extent. On the other hand, pitches of the warps C according to the invention exist within a narrow range with the same set pitch value as shown in Fig. 7. Therefore, it is clear that a great improvement of accuracy is accomplished according to the invention.
If it is required to change kinds of weft unthreaded textiles S, the grooved roll 33 has to be exchanged with a grooved roll corresponding to a new kind of textile. For this purpose, the cylinders 38 are actuated so as to retract the piston rods 39 to move the urging pawls 43 away from the grooved roll 33, while the restraining roll 52 is retracted by the rotation of the screw shaft 53 to the position shown in phantom lines in Fig. 1. Thereafter, the motor 28 is energized so as to rotate the screw shaft 27 to move the carriage 30 in the rearward direction along the guide rails 29. When the grooved roll 33 supported by the support portion 32 arrives at the exchange position B, the carriage is stopped.
The cylinder 58 is then actuated so as to extend the piston rod 59 so that the grooved roll 33 is supported at its center and raised by the receiving member 60, thereby transferring the grooved roll 33 from the support portion 32 to the receiving member 60. After the grooved roll 33 is then removed from the receiving member 60, a grooved roll 33 corresponding to a weft unthreaded textile S next to be coated with rubber is arranged on the receiving member 60. Thereafter, the cylinder 58 is actuated so as to retract the piston rod 59 to transfer the new grooved roll 33 onto the support portion 32. The motor 28 is then energized to move the grooved roll 33 to the press-fitting position A.
As can be seen from the above explanation, any disturbances in pitch of warps of weft unthreaded textiles can be effectively prevented and rubber coating can be firmly applied to warps of weft unthreaded textiles according to the invention.
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details can be made therein without departing from the spirit and scope of the invention.

Claims

1. A coating method for weft unthreaded textiles comprising the steps of arranging warps (C) of a weft unthreaded textile (S) being fed in its longitudinal direction by individually guiding the warps without disturbing their pitches by a deep grooved roll (20), press-fitting the arranged warps of the weft unthreaded textile into a rubber sheet (6) on a calender roll (2) by forcing the warps into the rubber sheet by a grooved roll (33) which guides to arrange the warps again without disturbing their pitches; and, between the first arranging step and the press-fitting step, urging the weft unthreaded textile in a direction perpendicular to a surface of the weft unthreaded textile by a restraining roll (52) to change a moving direction of the weft unthreaded textile, thereby increasing a winding angle of the warps around the grooved roll (33) and preventing untwisting of the warps.

2. A method as claimed in claim 1, characterized in that when the weft unthreaded textile coated with the rubber sheet (6) is passing between the calender roll (2) and another calender roll (4) rolling each other, a rubber sheet (7) on the second mentioned calender roll (4) is pressed against an uncoated surface of the weft unthreaded textile to coat the surface of the weft unthreaded textile with the rubber sheet on the second mentioned calender roll.

3. A method as claimed in claim 1 or 2, characterized in that the grooved roll (33) is moved from a press-fitting position (A) nearest to the calender unit (1) to a roll exchange position (B) and exchanged for another grooved roll at the roll exchange position.

4. A coating apparatus for weft unthreaded textiles (S) comprising a deep grooved roll (20) formed in its outer circumference with a number of deep grooves (21) spaced in its axial direotion predetermined distances and rotatable about its axis to insert warps (C) of a weft unthreaded textile being fed in its longitudinal direction into said deep grooves to individually guide and arrange the warps without disturbing their pitches, a grooved roll (33) arranged downstream of said deep grooved roll with respect to the path of the weft unthreaded textile, said grooved roll being formed in its outer circumference with a number of shallow grooves (35) spaced in its axial direction predetermined distances and rotatable about its axis to insert the warps arranged by the deep grooved roll into said shallow grooves to individually guide and arrange the warps again without disturbing their pitches, press-fitting means (46) for pressing the grooved roll against a rubber sheet (6) on a calender roll (2) to force the warps in the shallow grooves into the rubber sheet, a restraining roll (52) rotatably arranged between said deep grooved roll (20) and said grooved roll (33) and able to be in contact with a surface of the weft unthreaded textile, and urging means (54) for urging the restraining roll in a direction perpendicular to a surface of the weft unthreaded textile to change a moving direotion of the weft unthreaded textile, thereby increasing a winding angle of the warps around the grooved roll (33) and preventing untwisting of the warps.

5. Apparatus as claimed in claim 4, characterized in that said press-fitting means (46) comprises a pair of cylinders (38) mounted on a frame (11) of the apparatus, a connecting plate (40) mounted on the cylinders movably toward and away from the calender roll when the cylinders are actuated, guiding means (42) for guiding the moving connecting plate, and urging pawls (43) fixed to the connecting plate for supporting said grooved roll (33).

6. Apparatus as claimed in claim 4 or 5, characterized in that said urging means (54) comprises a lifter (50) rotatably supporting at a lower end said restraining roll (52), a plurality of screw shafts (53) whose lower ends threadedly engage the lifter to cause the lifter to raise and lower when the screw shafts are rotated, and a motor for rotatively driving the screw shafts.

7. Apparatus as claimed in any of claims 4 to 6, characterized by further comprising grooved roll exchange means (62) including a cylinder (58) fixed to a frame (11) of the apparatus at a grooved roll exchange position (B) and a receiving member (60) mounted on the cylinder and movable when a piston rod (59) is extended and retracted and having a shape capable of supporting and raising said grooved roll (33) positioned at the exchange position (B) when the piston rod of the cylinder is extended.

8. Apparatus as claimed in claim 7, characterized by further comprising means for moving the grooved roll between a press-fitting position (A) nearest to the calender unit (1) and a grooved roll exchange position (B) remote from the calender unit.