JP2706698B2 - Pressing body and reduction 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 moving plate-shaped or strip-shaped strip of metal, paper, film, or the like, which comes into contact with both or one side or the surface of a rotating roll. TECHNICAL FIELD The present invention relates to a pressing body for rolling down a range of a certain length in a direction, and a pressing device using the pressing body. Further, the present invention relates to an apparatus capable of heating or cooling a moving body while pressing the moving body in a predetermined length range. That is, the term "pressing device" as used in the present invention refers to a device that directly uses a pressing force, for example, a laminator for bonding two or more strips, an embosser for embossing a surface of a strip, and a wide pressing area. This is a broad concept including a device such as a roll coater that coats paint or the like, or a device that heats or cools a strip or the like using a pressing force and a large area. Further, as described above, the moving body includes a rotating object such as a roll in addition to a strip entrained in a certain direction. Hereinafter, the strip will be described as a representative for simplicity.

[0002]

2. Description of the Related Art Conventionally, when a pressing force is applied to the surface of a moving body such as a strip, a roll that rolls on the moving body is used to reduce the friction of the surface. For example, there is a case where a pair of cooperating rolls is used for supplying and bonding the sheet material, or a roll is pressed against one surface of a traveling strip. In such a device, it is necessary that the contact portion of the roll is deformed so as to be flat by a rolling force or a pressing force, and is brought into contact with an appropriate contact length (hereinafter, referred to as a nip length). 2. Description of the Related Art Conventionally, in a device that sandwiches a strip with two rolls facing each other and presses the roll against the strip, or a device that presses the roll against the strip, a nip length is required due to the flatness of the roll due to a pressing force or a pressing force. The reason for this is that if the nip length is absent or short, the strip and the roll are in line contact with each other and the rolling force per unit area is excessive. Further, when it is necessary to transfer heat between the slip and the roll, there is a problem that the strip and the roll do not have a contact area in a line contact, so that heat cannot be transferred at a contact portion. Therefore, metal rolls that do not deform significantly with rigidity cannot be used for these devices because the nip length cannot be obtained,
At present, a rubber roll is used for at least one of the rolls. However, rubber rolls cannot be used at high temperatures because of (1) heat resistance, (2) high pressure cannot be applied at high speed due to rubber strength, and (3) rubber life is short and roll replacement frequency is low. There were many problems.

Further, in a laminator or an embosser backup roll which needs to transfer heat from the strip, water may be supplied to the roll to cool or heat the inside of the roll, but in order to obtain a nip length, If a rubber roll, particularly a rubber roll having a large rubber thickness, is used, heat transfer cannot be sufficiently performed. There is also a method in which the metal is cooled and the heating roll is contacted and rotated from the outer surface of the rubber roll. However, there is a problem in that the heat transfer of rubber is low and heat transfer cannot be sufficiently performed due to indirect heat transfer. In the case of a device that heats or cools the strip by blowing hot or cold air on the strip, it is conceivable to use a rubber roll instead of a metal roll to reduce the opposing pressure. However, it is not possible to sufficiently heat or cool the strip for the reasons described above. Absent. Therefore, conventionally, a metal roll having a short nip length is unavoidably used. Furthermore, rapid cooling was performed by directly inserting the strip into the liquid, which was not possible in a dry state.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pressing member and a pressing device which are excellent in heat resistance, have a long life even at high speed and high pressure, and can obtain a required nip length. . Another object of the present invention is to provide a method for producing a large heat flow at high speed or high temperature of a strip.
An object of the present invention is to provide a rolling reduction device capable of effectively controlling a strip temperature to a target temperature.

[0005]

A pressing body according to the present invention is a pressing body for contacting and pressing at least one surface of a moving body, and (a) a flat portion whose outer peripheral surface faces the moving body. And a shaft-shaped sleeve support having a flat curved surface composed of a flat portion and a continuous curved surface portion; and (b) an outer circumferential surface of the sleeve support capable of being fitted around the outer periphery of the sleeve support so as to be freely rotatable. It is characterized by comprising a flexible endless sleeve, and (c) a fluid filled and held in a gap between the sleeve support and the sleeve. In such a pressing body, it is preferable that a fluid ejection port is provided in a flat portion of the sleeve support, and it is more preferable that the fluid is a liquid. Further, the fluid is preferably oil, and a fluid in which a fluid outlet is also provided on the curved surface of the sleeve support is also preferred. A pressing body provided with a guide for receiving an axial force applied to the sleeve is preferably provided between the sleeve support and the sleeve, and the guide is rotatably housed at one end of the sleeve support. A pressing body composed of a group of rolling elements and a retainer fixed to the inner surface of the sleeve while holding the groups of rolling elements at an interval is more preferable.
The sleeve is preferably formed of a thin plate mainly composed of metal, and the sleeve is preferably formed by lining a thin metal plate on the surface of a polymer material. Further, in the pressing body providing the fluid ejection port in the flat portion of the sleeve support, a recess forming the accumulator,
It is preferable that the fluid ejection port is constituted by the porous fluid resistance member covering the recess. Preferably, the fluid resistance member is made of an annealed metal having continuous ventilation holes. Further, it is preferable that the fluid resistance member is constituted by an independent small tube group, and on the downstream side with respect to the rotation of the sleeve at the fluid ejection port of the sleeve support,
It is preferable that a fluid outlet is provided. The pressing-down device of the present invention includes the pressing member, a supporting member that supports a sleeve support of the pressing member such that a flat surface faces the moving member, and elastically urges the supporting member toward the moving member. Means. In such a reduction device, a device for heating and / or cooling the fluid includes a heat exchanger provided in a fluid supply pipe, and a heat medium or a fluid supply pipe passed through the heat exchanger. It is preferable to include a flow control valve provided in the passage. Further, the apparatus for heating and / or cooling the fluid includes a heat exchanger provided in a supply pipe for the fluid, and a heat medium passed through the heat exchanger or a flow control provided in the supply pipe for the fluid. It is preferable that the fluid is an oil,
Preferably, the heat medium is water. Further, it is also preferable to include a temperature sensor that detects the temperature of the sleeve and a temperature display controller that controls the temperature of the flow rate control valve so as to eliminate a deviation between the detected value of the temperature sensor and a target value. Those having a device for heating and / or cooling are more preferred. Further, it is also preferable that the pair of pressing members are arranged so as to be displaced from each other in the axial direction, and the guide according to claim 6 is provided at the end of the shaft on the side where each pressing member projects. Further, it is preferable that the pressing members are arranged in a pair so as to sandwich the moving member, and that a means for biasing at least one pressing member toward the moving member is provided.

[0006]

The pressing body of the present invention holds the sleeve support so as to be perpendicular to the moving direction of the moving or rotating moving body and the flat portion side is directed to the moving side, and the pressing body is mounted on the surface of the moving body. Use by pressing the sleeve. At that time, the sleeve is pressed against the moving body with a nip length equal to the length of the flat portion. In addition, since the outer peripheral surface of the sleeve support is a flat curved surface including the flat portion and the curved surface portion, the flexible sleeve is smoothly deformed on the outer peripheral surface of the sleeve support at the same speed as the moving body. Orbit. At this time, the fluid in the gap of the sleeve support has a lubricating action and a pressure holding action. Further, the fluid serves as a heat medium, so that cooling and heating of the sleeve can be performed efficiently. When a fluid ejection port is provided in a flat portion of the sleeve support, fluid is ejected to a portion of the nip where the sleeve comes into contact with the moving body, so that the sleeve is supported at a pressure that overcomes the pressing force. Orbiting in a state of ascending. Therefore, the lap is smooth. In addition, by forming the fluid ejection port of the sleeve support with the recess forming the pressure storage chamber and the fluid resistance member, local fluid film rigidity can be obtained, and a stable fluid film thickness can be obtained with the sleeve support of the nip portion and the sleeve. Can be formed and maintained between. At the same time, the fluid can intensively cool or heat the inner surface of the sleeve at the nip. The material of the sleeve is preferably a metal at least in terms of strength, but if there is a problem in contact with the strip and the metal, a thin resin material such as synthetic resin or rubber may be used for the metal sleeve. In addition, by ejecting the fluid from the portion other than the nip portion, that is, the curved surface portion, to the inner surface of the sleeve, the entire circumference of the sleeve can be used as a heat transfer surface, and heat transfer can be performed more effectively. In addition, positively interposing a fluid between the sleeve support and the sleeve other than the nip portion further improves the lubricating action during this time.
Further, it is preferable to make the fluid a liquid in order to make the present invention effective. Since the liquid has a higher viscosity than the gas and is incompressible, the pressure of the liquid film in the nip portion can be increased with a small flow rate, and the pressure can be reduced by a high pressure. At the same time, liquid has a larger heat equivalent per unit volume than gas,
A large amount of heat can be moved with a small flow rate, and the heating capacity or cooling capacity of the pressing body can be increased. By adjusting the temperature or the flow rate of the fluid ejected to the nip portion and the inner surface of the sleeve other than the nip portion, the temperature of the steel belt roll or the nip exit temperature of the strip can be controlled for the purpose. In order to more reliably operate the pressing body of the present invention, it is preferable to support an axial force generated when the sleeve is rotated while being pressed down. For this purpose, for example, a guide such as a thrust bearing is provided between the sleeve and the sleeve support. In the case of a guide, a plurality of small-diameter rollers are placed and fixed on the inner circumference of the end of the sleeve using a bearing retainer, etc., a groove is provided on the outer circumference of the sleeve support, and the rollers etc. run along the groove. It can be adapted to any cross-sectional shape of the sleeve support. When the cross-sectional shape of the sleeve support is close to a circle, a commercially available bearing can be used. Since a commercially available bearing is not easily deformed flat, it is preferably provided at a position apart in the axial direction which does not affect the deformation of the sleeve. When the pair of pressing members are opposed to each other, it is preferable that only one of the pressing members is disposed on the opposite side of the shaft end, and is shifted from the other sleeve in the axial direction. Thereby, a bearing with little deformation can be used.

[0007]

Next, embodiments of the present invention will be described in detail with reference to the drawings. <Principle and Flow of Fluid> FIG. 1 is a cross-sectional view showing an embodiment of a pressing-down device according to the present invention.
A shows a state in which the slip is being reduced. FIG. 2 is an axial cross-sectional view passing through a nip portion of one pressing body A. 1 and 2, 1 is a sleeve support, 2 is a sleeve, and 3 is a strip. 4 is a nip portion, 5 is a fluid conduit in the sleeve support 1, 6 is a fluid accumulator,
7 is a fluid resistance member, 8 is a pocket on the outlet side of the fluid and an axial pocket which serves as an axial conduit for the fluid, and 9 is an inlet for the fluid into the sleeve support 1. Arrows indicate the direction of travel of the strip and sleeve and the direction of fluid flow. In this embodiment, the cross section of the sleeve support 1 is circular, and the fluid resistance member 7 at the corresponding portion forms an approximately flat surface. It does not necessarily have to be a flat surface. The fluid entering the sleeve support through the inlet 9 enters the pressure accumulating chamber 6 through the conduit 5, where the fluid has a static pressure, and flows out through the fluid resistance member 7 to the inner surface of the sleeve at the nip portion. At this time, since the fluid resistance member 7 is intended for local fluid film rigidity, it is constituted by independent small pipe groups, and the pressure loss due to the pipe resistance is preferably several times the pressure acting on the inner surface of the sleeve. The fluid resistance member 7 may be replaced with a sintered alloy having open cells. Thus, the fluid that has passed through the fluid resistance 7 forms a fluid film having sufficient local rigidity between the sleeve 2 at the nip portion and the sleeve support 1, and the sleeve 2 floats from the sleeve support 1 and has extremely low frictional force. Make a small smooth slide, sleeve 2
Can go around the outer periphery of the sleeve support 1. The fluid forming the fluid film moves in the circumferential direction and enters the axial pocket 8. The axial pocket 8 is axially continuous and fluid is discharged out of the end of the sleeve support.

<Cross Section Shape of Sleeve Support> The sleeve is preferably formed of a thin metal plate, particularly a steel belt. Hereinafter, such a pressing body is referred to as a steel belt roll. Since the sleeve 2 is repeatedly bent along the shape of the sleeve support, the thinner the better, in order to reduce the bending stress. However, it must withstand the rolling force on the strip and the shearing force acting on the portions in contact with both ends of the strip. As a countermeasure, it is desirable to select a high-tensile steel material having a tensile strength of about 200 kgf / mm ² for the sleeve and to increase the minimum bending radius of the sleeve. However, stainless steel can be used as long as it is a metal having a large fatigue strength value. The cross-sectional shape of the sleeve support is not limited to a circular shape, and any shape may be good in principle, but a shape having a large minimum bending radius is preferable. It is desirable that the entrance side and the exit side of the nip portion have smooth curves.
For example, as shown in FIG. 3, the shape of the sleeve is the length of the flat portion 4a, that is, the nip length is L, the radius between 90 degrees from the nip is r, 180 degrees is R, and R = r + L / 2. Alternatively, a flat portion 4b may be provided on the opposite side of the flat portion 4a of the nip portion as shown in FIG.

<Ejection on Heat around Sleeve Support and Heat Transfer Efficiency>
No pressure is applied to the sleeve support other than the nip portion and the inner surface of the sleeve unless an external force is applied. However, as shown in FIG. 5, if the fluid ejection port 5a is arranged a plurality of times on the circumference, the rotation of the sleeve 2 is more stable. I do. Of course, these additional jets 5 a may have a lower liquid film pressure and flow rate than the nip 4. Therefore, if branching from the same conduit as the nip portion, the circumferential length of the ejection surface may be short, and the pressure loss of the fluid resistance 7 may be large. In addition, the supply of fluid and the pipeline in this portion can be made independent to reduce the pressure. By providing a large number of jets in this way, when a large amount of heat is exchanged between the strip 3 and the steel belt roll, the fluid and the inner surface of the sleeve can be exchanged over the entire circumference, thereby further improving the heat transfer efficiency. When a portion other than the nip portion is rolled down from outside by another roll or the like, a fluid ejection port corresponding to the rolling down force may be provided, and the strip 3 may be formed by a steel belt roll A.
In the case of winding, the ejection port and ejection pressure may be set according to the position, length, and winding tension.

<When the fluid is a liquid> If the fluid is a liquid, a large rolling force can be applied to the nip portion at a small flow rate as compared with a gas, and the heat transfer efficiency is greatly improved.
Further, if water is used as the liquid, the handling is easy. However, if an appropriate oil is used, the viscosity can be increased and a high pressure can be obtained, and operation can be performed at a high temperature by using an oil having a high boiling point.

<Temperature Control of Steel Belt Roll> When the steel belt roll is used as a laminating roll for laminating a film by heat welding a metal strip, the temperature greatly affects the quality. In such a case, it is preferable to control the temperature of the fluid ejected from the sleeve support 1 to the inner surface of the sleeve by measuring the temperature of the sleeve 2. The method is shown in FIG. In FIG. 6, the difference between the target temperature of the sleeve and the actual measured value of the sleeve temperature detected by the temperature sensor 10 is fed back to the opening of the cooling water valve 11 by the TIC (temperature display controller) 14, and the fluid and heat circulated by the pump 12 The temperature of the fluid is controlled via the exchanger 13. In FIG. 7, the deviation is fed back to the valve 15 for controlling the flow rate of the jet, and the temperature of the sleeve is controlled by controlling the flow rate. However, in this case, it is necessary to maintain the flow rate within the allowable range of the thickness of the fluid film in the nip portion, so that the controllable range of the temperature is limited thereto.

Next, an embodiment in which the apparatus of the present invention is applied to a laminating apparatus for thermally welding a film to both sides of a steel plate will be described. FIG. 8 is a system diagram of the apparatus. Hot steel plate 3
Traveling from top to bottom, the film 21 conveyed from both sides is wound around the steel belt rolls 20a and 20b facing each other, and the steel plate and the film are simultaneously pressed down at the nip portion, and at the same time, the steel plate is required for film characteristics. Laminate by cooling to temperature. One steel belt roll 20 a is fixed by the support member 22, and the other steel belt roll 20 b is lowered by the air cylinder 23. Oil is used as the fluid, and the steel belt rolls 20a and 20b are provided with independent circulation systems. The circulating system supplies the steel belt rolls 20a and 20b with the high-pressure pump 12 and the high-pressure pipe 25 for jetting the nip portion from the circulating tank 24, and the low-pressure pump 26 and the low-pressure pump 26 for jetting at a low pressure other than the nip portion. It is supplied through a pipe 27. The heat exchanger 13 is interposed in the middle of the low-pressure pipe 27, and the oil is cooled by the cooling water 29. The cooling heat quantity is controlled by measuring the temperature of the surface of the steel belt roll 20, that is, the sleeve, by the temperature sensor 10, and controlling and adjusting the control valve 11 by the TIC 14 according to the deviation from the target temperature of the steel belt roll 20. It is done by doing. The reason why the heat exchanger 13 is incorporated in the low-pressure pipe 27 is that the pressure resistance of the heat exchanger 13 can be reduced. Since the return oil from the steel belt roll 20 is a mixture of high pressure and low pressure, it is returned by the return pipe 33 so as not to increase the back pressure.

Next, the steel belt rolls 20a and 20b used in the rolling-down device will be described. FIG. 9 is a sectional view of the center of the pair of steel belt rolls 20a and 20b, and FIG.
FIG. 10 is a sectional view in the axial direction of BB in FIG. 9. 9 and 10
8 will be described. The oil supplied from the high-pressure pipe 25 shown in FIG. 8 enters the high-pressure oil inlet 9 provided at one end of the sleeve support 1 and enters the accumulator 6 through the pipe 5. Here, a static pressure is applied and the fluid passes through the fluid resistance member 7 made of open-cell sintered alloy and is ejected toward the inner surface of the sleeve at the nip portion. The jetted oil causes the sleeve 2 to float from the sleeve support 1, cools the sleeve 2, flows to both sides through an axial pocket 8 a provided in a groove shape in the axial direction of the sleeve support 1, and It flows into annular pockets 40 provided in a groove shape on the outer periphery of both sides of the body 1. The oil supplied from the low-pressure pipe 27 in FIG. 8 enters through a low-pressure oil inlet 41 provided at multiple ends of the sleeve support 1, and enters a pressure accumulation chamber 46 through a pipe 45. Here, a static pressure is applied, and the fluid is ejected to the inner surface of the sleeve through the fluid resistance 47 of the open-cell sintered alloy. The jetted oil lifts or lubricates the sleeve 2 from the sleeve support 1 and cools the sleeve 2, and passes through the respective axial pockets 8 b provided in a groove shape in the axial direction of the sleeve support 1, so that the oil is ejected from both sides. And flows into the annular pockets 40 on both sides of the sleeve support 1 and collects with the flow from the high pressure pipe. An oil seal 42 conforms to the shape of the sleeve. The oil seal 42 prevents oil leaking from the annular pocket 40 to both sides. Naturally, the cross-sectional area of the pipe after the annular pot 40 is sufficiently large to reduce the back pressure. The oil collected in the annular pocket 40 is discharged to the outside of the steel belt roll 20 through the outlet pipe 43, and returns to the circulation tank 24 via the return pipe 33 in FIG. 50 is a guide groove provided on the outer periphery of the sleeve support 1. Reference numeral 51 denotes a guide roll attached to the inner surface of the sleeve so as to fit into the guide groove 50. This guide roll 51 functions as a thrust bearing,
It circulates along the guide groove 50 and can support the axial force generated in the sleeve 2. 8 to 10 show a double-sided laminating apparatus, a single-sided laminating apparatus may be used. If the film 21 is not inserted in this device, the device becomes a cooling device for the strip 3. If the oil is heated by the heat exchanger 13 without inserting the film 21, a strip heating device can be obtained.

[0014]

According to the present invention, a metal surface roll can be provided in an apparatus or the like for rolling down a strip against a roll which could only be used as a conventional rubber roll. As a result, the life of the roll is prolonged, and heat is directly transmitted from the inner surface of the roll through the thin-walled sleeve, so that it is possible to control the transfer of a large amount of heat. In particular, in the production of a laminated plate, such as when a film is heat-welded to a metal strip, high-speed production becomes possible by using the pressing device of the present invention as a laminator. Further, if the rolling-down device of the present invention is applied to a conventional device for heating or cooling a strip by blowing hot or cold air, heating or cooling can be performed in a short time, that is, in a very short length. further,
The conventional method of quenching is a method of directly immersing in a liquid, but cooling by the apparatus of the present invention enables quench in a dry state without directly contacting the strip with the liquid.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a pressing body of the present invention.

FIG. 2 is a sectional view of the pressing body of FIG. 2;

FIG. 3 is a contour view showing one embodiment of a sleeve according to the present invention.

FIG. 4 is a contour view showing another embodiment of the sleeve according to the present invention.

FIG. 5 is a contour view showing another embodiment of the pressing body of the present invention.

FIG. 6 is a fluid circuit diagram showing an embodiment of the rolling-down device of the present invention.

FIG. 7 is a fluid circuit diagram showing another embodiment of the drafting device of the present invention.

FIG. 8 is a fluid circuit diagram showing still another embodiment of the drafting device of the present invention.

9 is a cross-sectional view of a pressing body in the pressing-down device of FIG.

FIG. 10 is a sectional view taken along line BB of FIG. 9;

[Explanation of symbols]

 A Steel belt roll 1 Sleeve support 2 Sleeve 3 Strip 4 Nip section 5 Pipe line 6 Accumulation chamber 7 Fluid resistance member

Claims (20)

(57) [Claims] 1. A pressing body for contacting and pressing at least one surface of a moving body, wherein (a) an outer peripheral surface has a flat portion facing the moving body, and a smooth curved surface continuous with the flat portion. (B) a flexible endless sleeve that is fitted around the outer peripheral surface of the sleeve support so as to be freely rotatable; A) a pressing body comprising a fluid filled and held in a gap between the sleeve support and the sleeve. 2. The pressing body according to claim 1, wherein a fluid ejection port is provided on a flat portion of the sleeve support. 3. The pressing body according to claim 1, wherein the fluid is a liquid. 4. The pressing body according to claim 1, wherein the fluid is oil. 5. The pressing body according to claim 1, wherein a fluid outlet is also provided on the curved surface of the sleeve support. 6. The pressing body according to claim 1, wherein a guide for receiving an axial force applied to the sleeve is provided between the sleeve support and the sleeve. 7. A group of rolling elements housed rotatably at one end of a sleeve support, said guides holding said group of rolling elements at an interval, and are fixed to the inner surface of the sleeve. 6. The pressing body according to claim 5, comprising a retainer. 8. The pressing body according to claim 1, wherein the sleeve is formed of a thin plate whose main component is metal. 9. The pressing body according to claim 1, wherein the sleeve is formed by lining the surface of a thin metal plate with a polymer material. 10. The pressing device according to claim 2, wherein the fluid ejection port formed in the flat portion of the sleeve support comprises a recess forming the accumulator, and a porous fluid resistance member covering the recess. body. 11. The pressing body according to claim 10, wherein the fluid resistance member is made of an annealed metal having continuous ventilation holes. 12. The pressing body according to claim 10, wherein said fluid resistance member is constituted by a group of independent small tubes. 13. The pressing body according to claim 2, wherein a fluid discharge port is provided on a downstream side of the sleeve support at a fluid ejection port with respect to rotation of the sleeve. 14. The method of claim 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11 or 12, a supporting member for supporting a sleeve support of the pressing member such that a flat surface faces the moving body, and the supporting member is elastically moved toward the moving body. A pressing device comprising a biasing means. 15. An apparatus for heating and / or cooling the fluid, comprising: a heat exchanger provided in a supply line of the fluid; and a heat medium passed through the heat exchanger or provided in a supply line of the fluid. The pressure reduction device according to claim 14, comprising a flow control valve. 16. The reduction device according to claim 15, wherein the fluid is oil and the heat medium is water. 17. A temperature sensor for detecting a temperature of a sleeve, and a temperature display controller for controlling a temperature of the flow control valve so as to eliminate a deviation between a detected value of the temperature sensor and a target value. Screw down device. 18. The reduction device according to claim 14, further comprising a device for heating and / or cooling the fluid. 19. The method according to claim 14, wherein the pair of pressing members are disposed so as to be shifted in the axial direction, and the guide according to claim 6 is provided at the end of the shaft on the side from which each pressing member protrudes. Screw down device. 20. The method of claim 1, 2, 3, 4, 5, 6, 7,
A press-down device comprising: a pair of pressing bodies according to 8, 9, 10, 11 or 12 arranged so as to sandwich a moving body, and means for urging at least one of the pressing bodies toward the moving body.