JPH09183158A - Manufacture of cylindrical rubber sheet, and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the bonding force of a cylindrical rubber sheet, and reduce the change with the lapse of time by a method wherein the cross section of the leading end of an unvaulcanized rubber, for which either one of chloroprene rubber and natural rubber is made the major component, being cut by an ultrasonic cutter, and the cross section of the final end of the unvulcanized rubber which is cut in the same manner, are press-bonded. SOLUTION: The cross section of the leading end of an unvulcanized rubber sheet, for which either one of chloroprene rubber and natural rubber is made the major component being cut by an ultrasonic cutter 1, and the cross section of the final end of the unvulcanized rubber sheet which is cut by the ultrasonic cutter 1 in the same manner, are bonded by press-bonding. In order to do so, for the manufacturing device of the cylindrical rubber sheet, between a rubber sheet hanging table, and a cylindrical metal die 3 which is rotated by a motor 31 and is axially supported by a pedestal so as to be replaceable, a feeding roll 5, a cutting table 35 and a stitcher roll 4 are attached in such a manner that they can approach and separate from the cylindrical metal die 3 in parallel. Then, above the cutting table 35, the ultrasonic cutter 1 is attached in such a manner that it can run in the direction to go across the unvulcanized rubber sheet 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a cylindrical rubber sheet, which is formed by cutting and joining an unvulcanized rubber sheet (referred to as a sheet of unvulcanized rubber composition) to form a cylindrical shape. . For example, in the manufacturing process of a transmission belt, an unvulcanized coated rubber layer, a cord (tensile strength member), etc. are wound around the outer periphery of a cylindrical mold, and then an unvulcanized rubber sheet for the bottom rubber is wound and then Sulfur is cut into rings to produce a transmission belt. The tip of this unvulcanized rubber sheet for the bottom rubber is cut in the width direction of the rubber sheet, and is wound around the cylindrical mold while being pressed against it, and then the end portion (winding end portion) of the rubber sheet is cut. It is cut in the same manner as the tip portion, and the cut surface of the end portion is pressed against the cut surface of the tip portion to form a cylindrical rubber sheet. The present invention provides a method and an apparatus for manufacturing a cylindrical rubber sheet which is preferably used for cutting the unvulcanized rubber sheet to form a cylindrical shape. In particular, it is effective when manufacturing a cylindrical rubber sheet from an unvulcanized rubber sheet of a highly crystalline rubber used for a transmission rubber belt (for example, chloroprene rubber (trade name Neoprene BS manufactured by Dyupon Co., natural rubber)). .

[0002]

2. Description of the Related Art For example, a conventional method for producing a cylindrical rubber sheet by winding an unvulcanized rubber sheet for a bottom rubber around a cylindrical mold in a method for manufacturing a transmission belt will be described with reference to FIGS.

The rubber sheet 2'is rotatably installed on a rubber sheet stand (not shown) as a roll-shaped rubber sheet 10 'which is rolled into a roll with the release film 11' interposed therebetween, and the release film 11 'is separated. Meanwhile, it is sent out in the direction of arrow Y (the drive device is not shown). The rubber sheet 2'includes a guide roll 12 'and a dancer roll 3
4 ', the inspection table 36', and the roll 5'to the cutting table 35 '. The dancer roll 34 'buffers a change in tension applied to the rubber sheet 2' when the delivery roll 5 'starts and stops. The inspection table 36 'is a rubber sheet 2'
Has a portion for supporting the rubber sheet 2'flatly in order to visually inspect the appearance defect of the. The rubber sheet 2 'sent to the cutting table 35' is cut in the width direction by the cutter 1 '. A rotary blade or a linear cutter (trade name, Olfa cutter) (also referred to as a rotary blade) is used as the cutter 1, and cuts in a direction traversing the rubber sheet 2 ′ (direction orthogonal to the arrow Y). After cutting with a rotary blade or the like to improve the bonding strength, the cut surface is activated with a solvent such as toluene. Further, the rotary blade or the like may be heated and cut. The cut tip portion is manually guided to the upper surface of the cylindrical mold 3 ′, and the cylindrical mold 3 ′ is rotated and wound around once. FIG. 8 shows a procedure for winding the cylindrical mold 3 '.

The cut rubber sheet 2'is set on the upper part of the cylindrical mold 3'so that the ridgeline of its tip is parallel to the axis of the cylindrical mold 3 '(FIG. 8 (a)). ). Place the stitcher roll 4'on the rubber sheet 2 ', slowly rotate the cylindrical mold 3'in the direction of arrow Z, and place the rubber sheet 2'on the surface of the cylindrical mold 3'of unvulcanized rubber. It adheres by adhesiveness (FIG.8 (b)). After winding up to the end portion of the rubber sheet 2'which has been cut in advance according to the outer peripheral length of the cylindrical mold 3 ', the joint surface thereof is cut by the sewing machine roll 4
Using No. 1, a non-vulcanized cylindrical rubber sheet is formed by manually pressing (FIG. 8 (c)). In the power transmission belt manufacturing process, first, the coated rubber layer (sail cloth), the cord, etc. are wound around the cylindrical mold, and then the unvulcanized rubber sheet for the bottom rubber is wound, and further the vulcanization process is performed to cut into rings. It is common to finish with.

[0005]

However, the conventional method for manufacturing a cylindrical rubber sheet as described above has the following disadvantages.

In the manufacturing process of the power transmission belt, the unvulcanized rubber may be molded into a sheet and then proceed to the next cutting process after a certain period of work in progress, and the process of cutting the rubber sheet and the cylindrical mold may be performed. Since it is a separate process from the process of wrapping it around, it may be left for a certain period of time after cutting. In this case, if an unvulcanized rubber sheet mainly composed of rubber having high crystallinity such as chloroprene rubber or natural rubber is used, crystallization proceeds during this standing period and it becomes difficult to join the cut surfaces. Crystals are destroyed once when molded into these unvulcanized rubber sheets, so work such as joining and laminating is easy immediately after sheet molding, but over time, crystallization of rubber proceeds again and It is thought to be difficult to do. If the joining force at the end joining point (joint portion) of the rubber sheet becomes weak, cracks may occur at the joining portion after vulcanization.

In order to activate the joint surface of the unvulcanized rubber sheet, there is a method of applying a solvent such as toluene to the joint surface as described above. However, when the coating means is used to apply, for example, a cloth material, foreign matter such as fibers adheres to the cut surface or the solvent remains and causes cracking of the joint surface after vulcanization, and man-hours required for manual work There is a problem such as increase of.

When cutting with a heated rotary blade, crystallization progresses while the cut rubber cools and the bonding force decreases, so it is necessary to bond the rubber sheet before it is cooled. If the molding process is not continuous (when there is a residence time between cutting and joining), the effect of heating cannot be expected. In addition, there is a problem that the cross section is roughened due to adhesion of the melted rubber to the cut rotary blade.

In the case of cutting with a rotary blade as well as a straight blade, the width direction (lateral direction) of the rubber sheet at the time of cutting
May force the rubber sheet to move laterally, and the cutting line at the end of the sheet may not coincide with the leading end of the winding start (s in FIG. 9A, FIG. 9B). See angle r). Further, even during cutting, the rubber sheet may be strongly pressed partially due to variations in the thickness of the rubber sheet and the cutting line may be partially distorted (straightness deteriorates, as shown in FIG. (See (c)). Therefore, when the end portions are abutted with each other, the rubber sheets may be inclined and the tip portions may overlap with each other, or a portion having an insufficient length may occur.

The present invention has been made in view of the above points, and has a large joining force and little change over time, and further, foreign matter on the pressure contact surface which causes cracks and the like after vulcanization, distortion due to uneven size, etc. An object of the present invention is to provide a method and an apparatus for manufacturing a cylindrical rubber sheet that does not cause

[0011]

In order to achieve the above-mentioned object, a method for producing a cylindrical rubber sheet of the present invention is an ultrasonic cutter for an unvulcanized rubber sheet mainly containing at least one of chloroprene rubber and natural rubber. The cross section of the tip portion cut by the method and the cross section of the end portion of the unvulcanized rubber sheet similarly cut by the ultrasonic cutter are pressed into contact with each other to form a cylindrical shape.

The term "mainly composed of chloroprene rubber" means an unvulcanized rubber composition having a relatively high crystallization rate. When cutting an unvulcanized rubber sheet with an ultrasonic cutter, the blade contacts the rubber sheet while vibrating at a very high cycle and with a small amplitude, so the sheet does not need to be applied with a large lateral force. Does not move laterally, so no deviation occurs when the tip of the unvulcanized rubber sheet is attached to the cylindrical mold. Further, although the crystal of the rubber in the cut portion is destroyed by the vibration, the friction between the blade portion and the rubber sheet is limited to the blade edge portion, and only that portion generates heat. Therefore, only a small amount of heat is generated, and the crystal broken by cutting is stable without being recrystallized because it is cooled in a short time after cutting. Therefore, it is estimated that the activity of the cut surface can be maintained for a relatively long time after cutting.

The unvulcanized rubber sheet cut by the ultrasonic cutter in this way does not laterally shift during cutting,
It has a good bonding force not only immediately after cutting but also after being left for a certain period of time. Therefore, not only when cutting and joining continuous unvulcanized rubber sheets to form a cylindrical rubber sheet, but also when performing continuous joining after cutting a large number of unvulcanized rubber sheets, It is possible to maintain good bonding strength.

As described in claim 2, the cylindrical rubber sheet can be used as the bottom rubber of the transmission belt. In the method for manufacturing a power transmission belt according to claim 2, an unvulcanized rubber sheet for bottom rubber, which is mainly composed of chloroprene rubber used for the bottom rubber, is cut by an ultrasonic cutter,
By vulcanizing after forming a cylindrical rubber sheet by joining, good joining strength can be obtained, and cracks do not occur at the joined portion even after vulcanization.

An apparatus according to the present invention as defined in claim 3 is
A device for manufacturing a cylindrical rubber sheet by cutting an unvulcanized rubber sheet mainly composed of at least one of chloroprene rubber and natural rubber, and a) erection of a rolled-up rubber sheet so that it can be unwound. Between the rubber sheet mounting base and the cylindrical mold which is rotated by the drive means and is axially supported so that it can be exchanged, b) the delivery roll, the cutting base, and the cylindrical shape parallel to the cylindrical mold. It has a stitcher roll that can move in a direction in which it approaches and separates from the mold, and c) an ultrasonic cutter that can run in a direction that traverses the unvulcanized rubber sheet is provided above the cutting table. Stitcher roll
The rubber sheet is pressed against the cylindrical mold by being attached to the tip of the cutting table (downstream in the moving direction of the rubber sheet) so as to be movable in the direction of approaching and separating from the cylindrical mold.
After guiding the tip of the unvulcanized rubber sheet cut by the ultrasonic cutter between this stitcher roll and the cylindrical mold, contact the stitcher roll with the cylindrical mold and rotate the cylindrical mold. Thus, the rubber sheet can be mechanically wound around the cylindrical mold. The above-mentioned effects can be obtained by using an ultrasonic cutter.

The delivery roll according to claim 4,
Cutting table, stitcher roll and ultrasonic cutter
It can be mounted on a moving stand that can move in the direction of approaching and separating from the cylindrical mold. According to the device of claim 4,
Since the cutting table and the delivery roll move together with the stitcher roll, the distance between the delivery roll holding the rubber sheet and the stitcher roll becomes constant, and the positioning accuracy of the tip of the rubber sheet can be improved.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a method for manufacturing a cylindrical rubber sheet and an apparatus therefor according to the present invention will be described below with reference to Examples and the drawings.

The method for producing a cylindrical rubber sheet of the present invention is
As described above, the composition can be effectively applied when using an unvulcanized rubber sheet having a composition mainly composed of a rubber that is easily crystallized. Therefore, the composition of the target rubber will be described first.
That is, chloroprene rubber, natural rubber, and the like with specific trade names are shown below to show the slow crystallization rate.

Rubber type Crystallization rate ○ Chloroprene rubber (trade name Neoprene, manufactured by Deupon) Sulfur metamorphic type GS: Medium (5 days) GRT: Slow GT: Slow GN: Medium mercaptan metamorphic type W: Fast (1 day) WHV: Fast WRT: Very slow (40 days) ○ Natural rubber (NR) Medium ○ Styrene butadiene rubber (SBR) Not crystallized (The number of days in parentheses is the number of days that can be bonded after cutting by the cutting / bonding method of the present invention. In addition, the above-mentioned neoprene GS, GRT,
Although GT is preferably used, it is particularly effective for varieties containing Neoprene GS. Therefore, it is significant to use the ultrasonic cutter when cutting and joining the rubber used for manufacturing the power transmission belt.

After cutting an unvulcanized rubber sheet used for the bottom rubber of a typical transmission belt mainly composed of neoprene GS with an ultrasonic cutter, a round blade cutter and a straight blade cutter (trade name: Olfa cutter), The change in bonding force (also called tackiness) was measured. Experiments are only cutting and joining. The outline of each cutter is as follows.

Ultrasonic Cutter: As shown in FIG. 4 (a), it has a power supply 24 for supplying energy, a converter 23 and a booster 22 for converting this into vibration, and a horn 21 is provided at the tip thereof. The blade 25 is provided. The blade portion 25 is an ultra-hard straight blade (Fig. 4 (b), Fig. 4
(See (c)), the amplitude was 50 μm at maximum, the frequency was 20 kHz, and the cutting speed was 2 m / min.

Round blade cutter: Although not shown, the blade is a super hard round blade, the blade rotation speed is 150 rpm, the cutting speed is up to 4.3 m / min, and the cutting direction can be up-cut or down-cut. is there.

Straight-blade cutter: An Orfa cutter (product number 11K / L type) under the trade name is used.

A sample was prepared by kneading the composition containing Neoprene GS as a main component and having a thickness of 4.8 mm (usually 2 to 10 m).
m) cut into a square with a side of 60 mm,
Cut the joint surface with the cutter at a cutting angle of 30 °, abut with zero lapping allowance, and weigh 1000 g of 5
It was placed and bonded for a minute. The unvulcanized rubber sheet before cutting was used immediately after kneading and after being kneaded for 10 days. The measurement method is as shown in FIG.
One end of 4 is clipped and fixed to the fixing jig 55, and the other end is clipped to the pulling jig 51 and connected to the pull gauge 52. Pull the pull gauge 52 in the direction of arrow T,
The maximum load when the joint part 53 is broken is measured.

Table 1 shows the measurement results. The number of samples is 5,
The average value is shown, and the unit is kg / cm 2.

[0026]

[Table 1] After cutting, standing time Immediately after extrusion, 10 days after extrusion Ultrasonic round blade Olfa Ultrasonic round blade Orfa 1 hour 2.32 0.82 0.80 2.17 0.89 0.48 3 days 2.180 .79 0.55 0.86 0.71 0.41 5 days 1.06 0.74 0.38 0.60 0.53 0.24 7 days 0.85 0.37 0.32 0.60 --- As is clear from Table 1, the rubber immediately after extrusion was cut with an ultrasonic cutter, and the level of the bonding force immediately after cutting was maintained even after 3 days from the cutting, and the rubber was cut with a round blade or Olfa. It has a bonding force more than twice that of the above. Regarding the rubber 10 days after extrusion, the one cut by the ultrasonic cutter had a bonding force more than twice that of the one cut by the round blade after 1 hour, and showed a superior value even after that. There is.

The effect of the method for producing a cylindrical rubber sheet of the present invention can be evaluated by the linearity and parallelism of the cut surface. The linearity is evaluated by evaluating the linearity of the cut end portion of the rubber sheet. As shown in FIG. 6A, a straight edge ruler 56 is applied to the cut end portion to measure the maximum gap (c) therebetween.
The parallelism is to see the degree of orthogonality and the linearity with the side line of the upper surface ridge line of the cut end, and display a reference line (a) orthogonal to the side line of the rubber sheet at a position about 50 mm from the cut end. ,
From this reference line (a) to the ridgeline of the upper surface of the cut end, draw parallel lines (b) parallel to the rubber sheet side lines at intervals of about 10 mm, and make a difference between the maximum and minimum lengths of the parallel lines (b). Parallelism.

Table 2 shows the evaluation results of the parallelism and linearity of the round blade cutter and the ultrasonic cutter. Sample is 3-7
The points were measured, but only the average value is shown. The rotation of the round blade cutter was upcut (the blade tip was applied so as to rotate upward with respect to the cut surface). For reference, a large amount of rubber scraps adhere to the cut surface when down-cutting and are not subject to evaluation. The unit is mm.

[0029]

[Table 2] Round blade cutter Ultrasonic cutter Cross-section appearance Parallelism Linearity Cross-section appearance Parallelism Linearity △ 3.83 1.83 ○ 1.86 1.57 In the appearance evaluation, ○ is flat and △ is rubber scrap. Was.

Regarding the accuracy of the cutting angle (shown by θ1 and θ2 in FIG. 6 (b)), there is almost no difference when cutting with an ultrasonic cutter (1 °).
However, in a round blade cutter, this angle is 2-3
There was a variation of °. As can be read from these data, it is clear that the cutting surface formed by the ultrasonic cutter is flat and has good linearity, which is advantageous in improving the bonding force. The angle was measured by cutting the cut end of the rubber sheet along a plane perpendicular to the flow direction and measuring the angle of the projected photograph (magnification: about 20 times).
Due to the above-described unexpected effect, the cutting by the ultrasonic cutter has less decrease in the bonding force than the cutting by the round blade or the like immediately after the cutting and even after the elapse of a certain time.

An embodiment of the unvulcanized rubber sheet cutting device of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view for explaining the outline of an embodiment of the present invention, and FIG. 2 is a side view thereof.
FIG. 3 is a plan view thereof.

The apparatus for manufacturing a cylindrical rubber sheet shown in FIG. 1 (a) is rotated by a rubber sheet mounting base 65 and a motor 31 (driving means), and is replaceably mounted on a base 60 (see FIG. 2).
The delivery roll 5, the cutting table 35, and the stitcher roll 4 are mounted in parallel to the cylindrical mold 3 so as to be close to and separable from the cylindrical mold 3 pivotally supported by the cutting mold 35. An ultrasonic cutter 1 is attached to the upper side of the unvulcanized rubber sheet 2 so that the ultrasonic cutter 1 can travel in a direction crossing the unvulcanized rubber sheet 2. In addition, the work procedure in the manufacturing process of the transmission belt,
First, a coated rubber layer, a cord, and the like are wound around the cylindrical mold 3, and then the unvulcanized rubber sheet 2 for the bottom rubber is wound to form one cylindrical rubber sheet 6. Subsequently, the cylindrical mold 3 around which the cylindrical rubber sheet 6 is wound is removed from the frame 60, and the vulcanization process and the ring cutting process are performed. FIG.
Shows the state where the winding of the cylindrical rubber sheet 6 is completed and the leading end portion 69 of the next rubber sheet is prepared on the cutting table 35.

The unvulcanized rubber sheet 2 is a release film 11
The roll-shaped rubber sheet 10 is prepared by being sandwiched between the roll-shaped rubber sheet 10 and the roll-shaped rubber sheet 10, and the release film 11 is separated and wound up and fed in the direction of the arrow Y. The release film 11 is sandwiched between the unvulcanized rubber sheets 2 having a property of adhering to each other when they are formed into a sheet in order to prevent them from adhering. The unvulcanized rubber sheet 2 is further supplied to the delivery roll 5 via the dancer roll 34 and the inspection table 36. The dancer roll 34 buffers changes in the tension applied to the unvulcanized rubber sheet 2 when the delivery roll 5 is started and stopped, and the inspection table 36 is provided with rollers 64 (see FIG. 2) on the upper surface thereof and is not added. The vulcanized rubber sheet 2 is supported horizontally and movably, and is used to inspect the appearance of the unvulcanized rubber sheet 2. The delivery roll 5 moves the rubber sheet 2 in the direction of the arrow Y in accordance with the progress of winding on the cylindrical mold 3.
Send in the direction. The delivery roll 5, the cutting table 35, the stitcher roll 4 and the ultrasonic cutter 1 are moved to the moving table 3
It is attached as a unit on top of 9. Cutting table 35
Cooperates with the ultrasonic cutter 1 to cut the unvulcanized rubber sheet 2 into a required size. A straight blade-shaped blade portion 35 (see FIG. 4A, thickness about 0.5 mm) of the ultrasonic cutter 1 has a slit (not shown, width 2) provided across the cutting table 35.
-3 mm).

When the stitcher roll 4 is wound, it is moved by the moving table 39 in the direction of the cylindrical mold 3 (in the direction of arrow X).
And has a function of pressing the unvulcanized rubber sheet 2 onto the cylindrical mold 3 and winding it. At the start of winding, the tip end portion 69 of the unvulcanized rubber sheet 2 is adjusted by the delivery roll 5 so as to be on the tangent line between the stitcher roll 4 and the cylindrical mold 3. Delivery roll 5 and stitcher roll 4
Since they are attached to the same moving table 39, the thickness and width of the unvulcanized rubber sheet 2 do not change due to the movement of the stitcher roll 4. After pressing the tip portion 69 of the unvulcanized rubber sheet 2 to the cylindrical mold 3, the cylindrical mold 3
Is rotated in the direction of arrow Z to wind the unvulcanized rubber sheet 2 around the circuit. Since the motor 31 of the cylindrical mold 3 is provided with the rotary encoder 68 (see FIG. 3) to control the rotation of the drive motor 67 (see FIG. 3) of the delivery roll 5, both rotate in synchronization. . It is also possible to make only the stitcher roll 4 movable by improving the accuracy of speed adjustment between the cylindrical mold 3 and the delivery roll 5 (the manufacturing apparatus according to claim 3). End part (joint part 7) after winding the unvulcanized rubber sheet 2 on the cylindrical mold 3.
Although it can be joined by a sewing machine roll as in the prior art, it is preferable to join by a mechanical force by a press contact bar 9 that can abut against the cylindrical mold 3 as shown in FIG. 1 (b).

FIGS. 2 and 3 show the embodiment shown in FIG. 1A in a side view and a plan view, and only the portions which could not be explained with reference to FIG. 1A will be additionally described. In FIG. 2, the cylindrical mold 3, the moving table 39, and the inspection table 36
Is attached to the top of the pedestal 60. The stitcher roll 4, the cutting table 35, the ultrasonic cutter 1, and the delivery roll 5 are placed on the upper part of the moving table 39. The moving base 39 is slidably attached to a rail 61 supported by a gantry 60 via a linear bearing 62, and is moved by an air cylinder 63. Rolled rubber sheet 1
0 and the release film 11 driven by the winding motor 66.
Is placed on a movable rubber sheet rack 65, and the cylindrical rubber sheets 6 (see FIG. 1A) are replaced every time a predetermined number of them are completed. Here, unvulcanized rubber sheet 2
Is fed by the winding motor 66 using the tensile strength of the release film 11. The dancer roll 34 is supported by a frame supported by a fulcrum 67 attached to a pedestal 60 and can move up and down.

FIG. 3 is a plan view of the present embodiment, showing the positional relationship between the drive motor 31 for the cylindrical mold 3, the rotary encoder 68 attached to the shaft thereof, and the drive motor 67 for the delivery roll 5.

A transmission belt is a product that can effectively utilize the method and apparatus for manufacturing a cylindrical rubber sheet of the present invention described above. The power transmission belt is often manufactured by processing and vulcanizing an unvulcanized composition containing chloroprene rubber and natural rubber, depending on its use. Although there are various configurations of the transmission belt, for example, in the manufacturing process of a belt called a low edge belt, after winding a covering rubber layer (including an outer cloth) and a core cord on a cylindrical mold,
Wind the unvulcanized rubber sheet for the bottom rubber, go through the vulcanization process,
Create a vulcanized cylindrical rubber sheet. This cylindrical rubber sheet is sliced into a ring-shaped belt. In the forming process of the low edge belt using the material having a high crystallization speed, the cylindrical rubber sheet manufacturing apparatus including the cutting / joining process of the unvulcanized rubber sheet by the ultrasonic cutter can be effectively utilized. .

[0038]

As is apparent from the above description,
The method of manufacturing the cylindrical rubber sheet of the present invention and the manufacturing apparatus used for the same have the following excellent effects, although some of them have already been mentioned.

(1) According to the method for manufacturing a cylindrical rubber sheet of the present invention, in the manufacturing process of a transmission belt or the like which is particularly required to have heat resistance, the unvulcanized rubber sheet is cut and left as a work-in-progress for a while. Even in such a case, a large joining force can be obtained and the joining force can be maintained for a longer period than in the case of cutting with a round blade cutter or the like. As a result, it is not necessary to wipe the cut surface with toluene etc.
Since the cut surface is not distorted, the joint is strong and does not change in size. Moreover, problems such as cracks do not occur after the product is manufactured.

(2) According to the method for manufacturing a cylindrical rubber sheet as claimed in claim 2, in the manufacturing process, the unvulcanized rubber composition to be the bottom rubber of the power transmission belt is processed into a sheet or cut. Even if there is a work-in-process period, the predetermined joining force can be maintained, so it is easy to adjust work-in-process between the cutting process and the joining process, and the finished transmission belt may cause cracks in the joint during running. No accident will occur.

(3) In the manufacturing apparatus according to claim 3, since the unvulcanized rubber sheet is cut by the ultrasonic cutter, the above (1)
The effect of can be easily obtained. Further, by having the stitcher rolls that are close to and separate from the cylindrical mold, the work of manually attaching the rubber sheet starting end portion to the cylindrical mold, which has been conventionally performed manually, can be mechanically performed.

(4) In the manufacturing apparatus according to the fourth aspect, since the sending roll, the cutting table, the ultrasonic cutter and the stitcher roll can be moved as a unit, unnecessary tension is not applied to the rubber sheet by moving the stitcher roll. The thickness and width of the unvulcanized rubber sheet are not changed.

[Brief description of the drawings]

FIG. 1 (a) is a perspective view illustrating an outline of the present apparatus according to an embodiment of the present invention, and FIG. 1 (b) is an enlarged view of a joint portion for joining rubber sheets on a cylindrical mold. is there.

FIG. 2 is a side view showing an embodiment of an apparatus for manufacturing a cylindrical rubber sheet of the present invention.

FIG. 3 is a plan view showing an apparatus for manufacturing the cylindrical rubber sheet of FIG.

FIG. 4 (a) is a front view showing the outline of a unit of an ultrasonic cutter used in the present invention, and FIG. 4 (b) is a blade portion 2.
5 is an enlarged front view of FIG. 5, and FIG. 4C is a side view of the blade portion 25.

FIG. 5 is a perspective view illustrating a method for measuring a joining force of a rubber sheet.

FIG. 6 (a) is a perspective view illustrating a method of measuring linearity of a cutting tip, and FIG. 6 (b) is a cross-sectional view illustrating a method of measuring a cutting angle.

FIG. 7 is a perspective view illustrating a conventional apparatus for manufacturing a cylindrical rubber sheet.

FIG. 8A to FIG. 8C are perspective views for explaining a procedure of cutting a rubber sheet and winding it around a cylindrical mold in a conventional method of manufacturing a cylindrical rubber sheet.

9 (a) is a plan view showing a defect in a joint portion in a conventional method for manufacturing a cylindrical rubber sheet, and FIG. 9 (b) is a plan view showing a state where the rubber sheet is inclined and pressed against the drum. It is a figure.

[Explanation of symbols]

 1: Ultrasonic cutter 2: Unvulcanized rubber sheet 3: Cylindrical mold 4: Stitcher roll 5: Delivery roll 6: Cylindrical rubber sheet 7: Joint part 10: Rolled rubber sheet 11: Release film 22: Booster 23: Converter 25: Blade 35: Cutting Stand 36: Inspection Stand 39: Moving Stand 65: Rubber Sheet Stand

Claims (4)

[Claims] 1. A cross section of a tip portion obtained by cutting an unvulcanized rubber sheet mainly containing at least one of chloroprene rubber and natural rubber with an ultrasonic cutter, and an end of the unvulcanized rubber sheet similarly cut with an ultrasonic cutter. A method for manufacturing a cylindrical rubber sheet, which comprises forming a cylindrical shape by joining by pressure contact with a partial cross section. 2. The method for producing a cylindrical rubber sheet according to claim 1, wherein the cylindrical rubber sheet is used as a bottom rubber of a transmission belt. 3. An apparatus for producing a cylindrical rubber sheet by cutting an unvulcanized rubber sheet mainly composed of at least one of chloroprene rubber and natural rubber, which is an unvulcanized rubber sheet wound in a roll shape. Between the rubber sheet mounting base for rewinding and the cylindrical metal mold which is rotated by the driving means and is exchangeably supported by the feeding roll, the cutting base, and the cylindrical metal mold. And having a stitcher roll that is movable in a direction in which it approaches and separates from the cylindrical mold, and above the cutting table, an ultrasonic cutter that can travel in a direction that traverses the unvulcanized rubber sheet is provided. An apparatus for manufacturing a cylindrical rubber sheet, which is characterized in that 4. The delivery roll, the cutting table, the stitcher roll, and the ultrasonic cutter are mounted on a movable table that can move in a direction of approaching and separating from the cylindrical mold. Manufacturing equipment for cylindrical rubber sheets.