JPH09109283A - Endless rubber belt and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endless rubber belt with a projecting strip reinforced with a core thread provided on the rear face in the peripheral direction and with such advantages that releasing a molding die after vulcanization is easy, reversing the rubber belt is unnecessary and the manhour of polishing is significantly reduced. SOLUTION: A rubber sleeve 16 of vulcanized rubber with plural pieces of recessed grooves 16a formed at a specified interval on the surface of a cylindrical body is fitted onto a mandrel 15 with a circular cross section. Then a rubber tube 17 for a rear layer consisting of unvulcanized rubber is fitted onto the surface of the rubber sleeve 16, then a core thread is wound around the rubber tube 17, and a rubber tube for a front layer of unvulcanized rubber is fitted onto the surface of the core thread layer. Further, the rubber tube for the front layer is vulcanized, then the mandrel 15 is drawn out after polishing the surface of the rubber tube for the front layer, and the rubber sleeve 16 is drawn out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless rubber belt having a ridge on its back surface for preventing meandering and a method for producing the same.

[0002]

2. Description of the Related Art Various conveyor rubber belts used for conveying bills and magnetic cards in currency exchange machines, cash dispensers and the like are known in which a ridge for preventing meandering is provided on the back surface in the longitudinal direction. ing. For example, Japanese Patent Publication Sho 60
JP-A-34450 discloses that an unvulcanized rubber layer is formed on a vulcanized cored bar, heated under pressure to be semi-vulcanized, and after demolding, the surface is ground to a required size, and a cotton thread or the like is formed thereon. The reinforcing core body is spirally wound, and unvulcanized rubber is further coated on the core body, heated under pressure to be vulcanized, and then the surface is polished to carve out a plurality of ridges. It is described to cut off between the ridges.

Further, in JP-A-62-27836, a cylinder made of semi-vulcanized rubber or vulcanized rubber is fitted into the core of a mold for transfer molding or injection molding,
A reinforcing thread is wound around it in a spiral shape, and then the core of the reinforcing thread is mounted in the mold, and the space between the reinforcing thread layer and the cylindrical outer mold having a plurality of circumferential grooves on the inner surface. Describes filling unvulcanized rubber, vulcanizing, demolding, and then cutting off between the ridges formed by the circumferential groove. Note that these are used by reversing since the ridges are formed on the outer surface of the belt.

However, in these methods, a rubber layer is fitted on a cylindrical cored bar or core having a smooth surface, a reinforcing thread is spirally wound on the rubber layer, and the rubber layer on the outer side is wound around the reinforcing layer. Since the ridge was formed by polishing or mold,
The reinforcing yarn formed a cylindrical reinforcing layer concentric with the cored bar or the core, and no reinforcing yarn was present on the ridge. Therefore, the rigidity of the ridges is smaller than that of the tubular part other than the ridges,
This was one of the causes of the deterioration of the meandering prevention function.

Further, in these methods, since the vulcanized product is used upside down, there is a problem that the inner diameter tends to vary. The method of grinding the ridges by polishing has a problem that the amount of polishing is increased, the amount of rubber is wasted, and the number of working steps is increased. It should be noted that forming the groove in the core in the circumferential direction to eliminate the need for reversal makes it difficult to remove the mold after vulcanization and has not been put into practical use.

[0006]

SUMMARY OF THE INVENTION The present invention is an endless rubber belt that can be used not only as a money changer or a cash dispenser but also as a paper feeding belt for a copying machine, a transfer belt for a copying machine or a printer, and the like. Provided with a ridge on the back side, the ridge is provided with an endless rubber belt reinforced with a core yarn, and at the time of its production, by using a special core, demolding is easy, and inversion is unnecessary, Moreover, the present invention provides a method for manufacturing a conveyor rubber belt that can significantly reduce the number of polishing steps.

[0007]

A method of manufacturing an endless rubber belt according to the present invention comprises a mandrel having a circular cross section, and a plurality of circumferential grooves formed at predetermined intervals on a surface of a cylinder made of vulcanized rubber. Is fitted, a back side rubber layer made of unvulcanized rubber is adhered onto the rubber sleeve, and a core thread is spirally wound at a dense pitch on the surface of the back side rubber layer,
A front side rubber layer made of unvulcanized rubber is adhered onto the core yarn layer, and a wrapping material is further wound on the core side rubber layer for vulcanization under tightening, and the surface of the front side rubber layer is ground into a cylindrical shape, Thereafter, the mandrel is pulled out, the rubber sleeve is pulled out, and the vulcanized tube including the vulcanized back side rubber layer, core yarn layer and front side rubber layer is cut into a predetermined width.

According to this method, the back side rubber layer is adhered on the rubber sleeve fitted to the mandrel, and the core thread is wound around the rubber sleeve.
Further, since the front side rubber layer is applied, and the wrapping material is wrapped and tightened, a part of the back side rubber layer facing the concave groove of the rubber sleeve is pushed into the concave groove, and accordingly, the core yarn layer is formed into the concave groove. Formed within. Therefore, by vulcanization, the endless rubber belt according to the first aspect of the invention, that is, the endless rubber belt in which the core yarn is arranged in the protrusion is obtained. Demolding after vulcanization and polishing is performed by removing the rubber sleeve from the mandrel together with the vulcanizing tube on the rubber sleeve, and then removing the rubber sleeve from the rubber layer on the back side of the vulcanizing tube. Moreover, it is not necessary to divide the mold as in the case of using a mold.

Further, in the obtained endless rubber belt, the ridges provided on the inner surface are reinforced by the core yarn, so that the rigidity is improved and the meandering is obtained when it is used as a feeding belt for paper feeding of a copying machine. Is reduced. Moreover, since the split mold is not used,
Unlike the case of using the split mold, no streak is formed at the joint, and the inner surface of the belt is formed smoothly, so that there is no need to scrape off the streak by polishing.

In the method for manufacturing the endless rubber belt, the rubber sleeve fitted to the mandrel serves as a mold for molding the inner surface of the endless rubber belt. The rubber forming the rubber sleeve is a molding mold. In order to enable repeated use as above, a rubber such as a silicone rubber and a fluororubber which has a good releasability from the backside rubber layer of the vulcanized tube and is excellent in heat resistance is preferable.

The outer diameter of the mandrel and the inner diameter of the rubber sleeve are set in accordance with the size of the endless rubber belt, but it is preferable to set the inner diameter of the rubber sleeve slightly smaller than the outer diameter of the mandrel. As a result, the rubber sleeve is fitted on the mandrel with its diameter expanded, so wrinkles do not occur on the rubber sleeve, and when the rubber sleeve is removed from the mandrel together with the vulcanization tube after vulcanization, the rubber sleeve It contracts and is easily separated from the back rubber layer.

The number and position of the protrusions on the inner surface of the endless rubber belt are arbitrary, and may be one in the center or two on the left and right. A groove is formed in the rubber sleeve according to the number and position of the protrusions. To be done. The width of the ridge is preferably 0.5 mm or more and the height is preferably 0.5 to 3.0 mm. Width is 0.5
If the height is less than 0.5 mm or the height is less than 0.5 mm, the ridges easily come off the groove of the pulley. And the height is 3.
If it exceeds 0 mm, it will be difficult to attach and detach to the pulley.

The back side rubber layer and the front side rubber layer formed on the above rubber sleeve are made of NR, SBR, N as in the conventional case.
Made of any rubber such as BR, IR, IIR, EPDM and urethane rubber. In that case, the back side rubber layer can be made by winding a rubber sheet of a certain thickness around the rubber sleeve, and the front side rubber layer around the core yarn layer. It is advantageous to extrude each rubber layer into a tube and fit it into a rubber sleeve or core thread layer. The preferable thickness of each of the back rubber layer and the front rubber layer is 0.3 to 5 mm.

The core yarn layer on the back rubber layer is produced in the same manner as in the conventional case. That is, by winding the core yarn in a spiral shape at a dense pitch, the core yarn is arranged substantially parallel to the circumferential direction. The core yarn includes a yarn having a relatively small elongation, for example, a twisted yarn of cotton yarn, a polyester fiber,
It is preferable to use multifilament yarns such as aramid fibers and ultra-high molecular weight polyethylene fibers, glass fiber yarns, etc., the thickness thereof is preferably 100 to 2000 denier, and the arrangement pitch is preferably 0.3 to 5 mm.

[0015]

1 is a cross-sectional view showing an example of an endless rubber belt 10 of the present invention, in which a circumferential direction (a direction perpendicular to the plane of the drawing) is almost between a back side rubber layer 11 and a front side rubber layer 12. A large number of core yarns 13a arranged in parallel are closely arranged to form a core yarn layer 1
3 is formed, and a ridge 14 having a square cross section is provided at the center of the back side rubber layer 11 in the width direction and runs in the circumferential direction. Then, a part of the core yarn 13a that constitutes the core yarn layer 13 is formed by the protrusion 14
The ridge 14 is reinforced by moving to the base of the.

Next, a method of manufacturing the endless rubber belt 10 will be described. In FIG. 2, reference numeral 15 denotes a mandrel having a circular cross section, and a rubber sleeve 16 made of vulcanized silicone rubber is fitted on the mandrel 15. The rubber sleeve 16 has a width corresponding to a plurality of the endless rubber belts 10, and a plurality of recessed grooves 16a corresponding to the protrusions 14 of the endless rubber belt 10 are formed on the surface thereof at predetermined intervals. The inner diameter of the rubber sleeve 16 is equal to the mandrel 15
Is set to be slightly smaller than the outer diameter of the mandrel 15, and the inner surface of the rubber sleeve 16 is in close contact with the surface of the mandrel 15.

Then, the rubber sleeve 16 on the mandrel 15 is fitted into the rubber tube 17 for back layer, which has been extruded in advance, while inflating with air to form the back side rubber layer 11, and the back side rubber layer 11 is formed. The core yarn 13a is wound on one end thereof in a spiral shape with a dense pitch to form a core yarn layer 13, and a rubber tube for the surface layer is fitted thereon similarly to the rubber tube 17 for the back layer. To form the front side rubber layer 12, and then the front side rubber layer 12
A wrapping material made of a polyester film is wound on the upper side while being tensioned, and heated under pressure to heat the back side rubber layer 1 described above.
1. The core yarn layer 13 and the front rubber layer 12 are vulcanized and integrated to form a vulcanized tube 18.

After the above-mentioned vulcanization is completed, the wrapping material is removed, the surface of the front rubber layer 12 is polished and smoothed, and then the mandrel 15 is pulled out from the rubber sleeve 16 as shown in FIG. The sleeve 16 is pulled out from the back side rubber layer 11, and then a vulcanized tube 18 composed of the vulcanized back side rubber layer 11, core yarn layer 13 and front side rubber layer 12 is cut in the middle of two adjacent ridges 14. The endless rubber belt 10 of FIG. 1 is obtained.

[0019]

[Example] A cylindrical mandrel 15 having an outer diameter of 40 mm and an inner diameter of 3
9 mm, thickness 3 mm, length 740 mm, cylindrical shape, width 2 on the surface
mm, depth 1 mm, concave grooves 16a at 37 mm intervals are fitted with silicone rubber rubber sleeves 16, and unvulcanized EPDM back tube rubber tubes (inner diameter 39 mm, thickness 1 mm) 17 is fitted to form the back side rubber layer 11, and a cotton yarn (30th count / 3) is wound on the back side rubber layer 11 as a core yarn 13a in a spiral shape at a pitch of 12 threads per 1 cm width to form the core thread layer 13. Further, an outer layer rubber tube (inner diameter 40 mm, thickness 1 mm) made of unvulcanized EPDM was fitted thereon to form the front rubber layer 12.

Then, a wrapping material made of a polyester film is strongly wound on the front side rubber layer 12,
Then, it was vulcanized in a vulcanizer with steam at a temperature of 150 ° C. for 60 minutes. Next, after removing the wrapping material and polishing the surface of the front rubber layer 12, the mandrel 15 and the rubber sleeve 16 are sequentially withdrawn, and the remaining vulcanization tube 1
8 is cut into a specified width, inner diameter 40mm, width 36mm, thickness 2
An endless rubber belt 10 having a ridge 14 having a width of 2 mm and a height of 1 mm at the center of the inner surface was obtained. The obtained endless rubber belt 10 is attached to a paper feeding device of a copying machine and used to convey paper.
The good result of no meandering was obtained.

[0021]

According to the invention described in claim 1, a core yarn layer composed of a large number of core yarns arranged substantially parallel to the circumferential direction is provided between the front and back rubber layers constituting the endless rubber belt, and the back surface is provided with the circumferential direction. In the endless rubber belt in which the ridges are projected, a part of the core yarn moves to the back surface side and is located in the ridges.
Rigidity of the ribs is improved, meandering is reduced, and the ribs can be manufactured by the invention described in claim 2, and are easier to manufacture than the conventional endless rubber belt in which the core yarn is not arranged in the ribs. .

According to the invention described in claim 2, the endless rubber belt according to claim 1 can be obtained. And vulcanization,
The mold release after polishing is performed by removing the rubber sleeve from the mandrel together with the vulcanization tube on the rubber sleeve, and then removing the rubber sleeve from the back side rubber layer of the vulcanization tube, so that the mold release is easy. Moreover, since the split mold is not used, there is no formation of streaks at the seams unlike when using the split mold, and the inner surface of the belt is formed smoothly.
Therefore, it is not necessary to polish the inner surface of the belt to scrape off the streaks.

According to the invention described in claim 3, in the method for producing the endless rubber belt according to claim 2, since a rubber sleeve made of heat resistant rubber such as silicone rubber or fluororubber is used, heat resistance is improved. Excellent, can be used repeatedly for forming an endless rubber belt, and can easily take out the rubber sleeve from the vulcanized rubber tube after vulcanization and polishing.

According to a fourth aspect of the present invention, in the method for producing an endless rubber belt according to the second or third aspect, the inner diameter of the rubber sleeve is set smaller than the outer diameter of the mandrel, and the mandrel is expanded while expanding the rubber sleeve. Since wrinkles do not occur on the rubber sleeve, the rubber sleeve shrinks when the rubber sleeve is pulled out together with the vulcanization tube from the mandrel after vulcanization and polishing. It is easy to separate from the layer.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of an endless rubber belt.

FIG. 2 is a vertical cross-sectional view when the inner layer rubber tube is fitted into the rubber sleeve.

FIG. 3 is a vertical cross-sectional view when the rubber sleeve is pulled out from the mandrel.

[Explanation of symbols]

10: Endless rubber belt 11: Back side rubber layer 12: Front side rubber layer 13: Core thread layer 13a: Core thread 14: Projection 15: Mandrel 16: Rubber sleeve 16a: Groove 17: Rubber tube for back layer 18: Vulcanization tube

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29K 83:00 105: 08

Claims (4)

[Claims] 1. An endless rubber belt in which a core yarn layer made up of a large number of core yarns arranged substantially parallel to the circumferential direction is provided between the front and back rubber layers constituting the endless rubber belt, and a circumferential protrusion is provided on the back surface. In the endless rubber belt, part of the core yarn moves to the back surface side and is positioned in the ridge. 2. A mandrel having a circular cross section is fitted with a rubber sleeve in which a plurality of circumferential grooves are formed at predetermined intervals on the surface of a tubular body made of vulcanized rubber. A back side rubber layer made of vulcanized rubber is adhered, a core yarn is spirally wound around the surface of the back side rubber layer at a dense pitch, and a front side rubber layer made of unvulcanized rubber is formed on the core yarn layer. Adhesion, further wrapping a wrapping material from above and vulcanizing under tightening, polishing the surface of the front rubber layer into a cylindrical shape, then pulling out the mandrel, then pulling out the rubber sleeve, A method for producing an endless rubber belt, which comprises cutting a vulcanized tube composed of a vulcanized back side rubber layer, a core yarn layer and a front side rubber layer into a predetermined width. 3. The method for producing an endless rubber belt according to claim 2, wherein the rubber sleeve is made of heat resistant rubber such as silicone rubber or fluororubber. 4. The method for manufacturing an endless rubber belt according to claim 2 or 3, wherein the inner diameter of the rubber sleeve is set smaller than the outer diameter of the mandrel, and the rubber sleeve is fitted into the mandrel while expanding. .