JP5907453B2 - Rubber sheet material cutting method with twisted cord - Google Patents

Description

The present invention relates to a method for cutting a rubber sheet material with a twisted cord, in which a rubber sheet material with a twisted cord in which twisted cords formed by twisting a large number of wires are embedded in parallel at intervals is cut along the cord.

  When cutting the rubber sheet material with cord, when cutting between the cord and the cord so that the cord embedded in the rubber sheet is not exposed by cutting, for example, when used as a constituent material for pneumatic tires etc. Required to maintain quality.

The cord inside the rubber sheet is not always embedded straight at regular intervals due to errors in manufacturing, and the rubber sheet itself is easily deformed, and the cord embedded inside deforms as the rubber sheet deforms. Sometimes.
It is necessary to cut such a rubber sheet material containing a cord along the cord between the cords so that the cord is not exposed and protrudes or is cut.
Therefore, there is an example in which the present applicant has applied earlier (see Patent Document 1).

JP 2006-75951 A

In Patent Document 1, a cutter blade piece having a tip edge piercing blade and a side edge cutting blade and a cutter blade piece having a side edge cutting blade are joined together with the cutting blades facing in opposite directions. Thus, a cutter is disclosed in which a rubber sheet material is cut by being pierced at the center in the width direction of the corded rubber sheet material and separated from each other . The pair of cutter blade pieces has a thickness of 0.5 mm to 2.0 mm, and the piercing blade of one cutter blade piece is formed in a tip edge that is bent into a U shape and projects in a tapered shape, and has a bending angle of 90 mm. A round with a radius of curvature of 2 to 6 mm and a radius of curvature of the tip edge bend of 2 to 6 mm, the angle between the two cutting edges of the blades is 40 to 80 degrees, and the radius of curvature of the cutting edge is 1 mm or less and with a.

In Patent Document 1, the piercing blade has a bending radius at the tip edge bent portion of 2 to 6 mm. If the cord embedded in the rubber sheet material is a twisted cord formed by twisting a number of wires, the twisted cord is The twisted , generally spirally curved wire has a radius of curvature of at least 15 mm or more, so a piercing blade with a radius of curvature smaller than the radius of curvature of the wire can easily penetrate into the twist of the twisted cord and twist May break the wire and cause the wire to protrude or cause cutting defects.

The present invention has been made in view of such points, and the object of the present invention is to provide a method for cutting a rubber sheet material containing a twisted cord, which can cut the rubber sheet material well without breaking the twist of the twisted cord. It is in.

In order to achieve the above object, the invention according to claim 1
A cutter having an arc-shaped piercing blade at the tip edge and a cutting blade at the side edge is prepared, the piercing blade is pierced into a rubber sheet material containing a twisted cord, and the rubber sheet material is cut by the cutting blade to rubber. In the method of cutting a rubber sheet material containing a twisted cord, which cuts the sheet material, the radius of curvature of the tip edge of the arc-shaped piercing blade is calculated from the radius of curvature of a wire that is twisted to form the twisted cord and is curved in a substantially spiral shape. A cutting method characterized by enlarging .

The invention according to claim 2
The rubber sheet material cutting method according to claim 1, wherein a width of the piercing blade is larger than a twist pitch of the twisted wire.

The invention described in claim 3
3. The method for cutting a rubber sheet material with a twisted cord according to claim 1 or 2, wherein a radius of curvature of the piercing blade is smaller than a length obtained by adding a required length of 15 mm or less to a radius of curvature of the wire. .

The invention according to claim 4
The rubber sheet material cutting method according to any one of claims 1 to 3, wherein a thickness of the cutter is smaller than an arrangement pitch of twist cords embedded in the rubber sheet material. .

The invention according to claim 5
The rubber sheet material cutting method with a twisted cord according to any one of claims 1 to 4, wherein the cutter includes a cutter blade piece including the piercing blade and the cutting blade, and a cutter blade including the cutting blade. pierce widthwise central portion of the rubber sheet material together and joined towards pieces of the two switching裂刃each other in opposite directions, characterized by the Turkey to cut the rubber sheet material by separating from each other at a distance .

According to the method for cutting a rubber sheet material containing a twisted cord according to claim 1, the radius of curvature of the curved tip edge of the piercing blade is larger than the radius of curvature of the twisted and substantially spirally curved wire constituting the twisted cord. When the piercing blade is pierced into the rubber sheet material with twisted cord, it does not get into the twist of the twisted cord, so it can be pierced by avoiding the twisted cord without breaking the twist. The rubber sheet material containing a twisted cord can be cut satisfactorily without protruding.

According to the method for cutting a rubber sheet material containing a twisted cord according to claim 2, since the width of the piercing blade is larger than the twisting pitch of the twisted wire, the piercing blade may gradually enter the twist of the twisted cord. Without breaking the twist.

According to the method for cutting a rubber sheet material containing a twisted cord according to claim 3, the radius of curvature of the piercing blade is smaller than a length Rw + r obtained by adding a required length r of 15 mm or less to the curvature radius Rw of the wire. When the radius of curvature is larger than Rw + 15, it is possible to prevent the sharpness of the rubber sheet material from being deteriorated.

According to the method for cutting a rubber sheet material containing a twisted cord according to claim 4, since the thickness of the cutter is smaller than the arrangement pitch of the twisted cord embedded in the rubber sheet material, the gap between the cords of the rubber sheet material is excellent. Can be cut.

According to the method for cutting a rubber sheet material containing a twisted cord according to claim 5, the cutter includes a cutter blade piece including the piercing blade and the cutting blade, and a cutter blade piece including the cutting blade. Is made of a pair of cutter blades that cut the rubber sheet material by being separated and separated from each other. The material can be cut efficiently and satisfactorily.

It is an enlarged front view of the cutter used for the cutting method of one embodiment of the present invention. It is the same side view. It is a perspective view of the holder of the cutting device which uses the cutter, and the rubber sheet material containing a twisted cord. It is explanatory drawing for demonstrating the structure of a twisted cord. It is the front view and side view just before starting the cutting | disconnection of the rubber sheet material containing a twist cord by the cutter. It is the front view and side view immediately after piercing with the cutter. It is a front view at the time of the cutting | disconnection by the cutter.

Hereinafter, an embodiment according to the cutting method of the present invention will be described with reference to FIGS.
An enlarged front view of the cutter 1 for cutting the corded rubber sheet material 50 according to the present embodiment is shown in FIG. 1, and a side view thereof is shown in FIG.
The cutter 1 includes a pair of left and right cutter blades 2 and 3 having a steel material thickness Dc of 1.5 mm. The horizontal direction perpendicular to the thickness direction of the cutter 1 is the left-right direction. The thickness Dc of the cutter blade pieces 2 and 3 is preferably 0.5 mm to 2.0 mm.

One cutter blade piece 2 has a piercing blade 2T formed at the tip edge (indicated by a lattice hatch in FIG. 1) and a cutting blade 2S formed at a side edge, and the other cutter blade piece 3 has a cutting blade 3S. Are formed on the side edges (indicated by hatched hatching in FIG. 1).
Both cutter blade pieces 2 and 3 are joined together by forming the shape shown in FIG. 1 by joining the cutting blades 2S and 3S in opposite directions.

The cutting blades 2S and 3S formed symmetrically with respect to the cutter blade pieces 2 and 3 are formed by forming an arc having a radius of curvature of about 4 mm on the side edge bent and recessed in a U shape.
The cutter blade piece 3 includes only the cutting blade 3S, and the other cutter blade piece 2 includes both the cutting blade 2S and the piercing blade 2T.

  The piercing blade 2T of the cutter blade piece 2 has a fan-like lower end developed in a fan shape downward from the constricted portions of the cutting blades 2S and 3S which are bent and recessed in the shape of a left and right wedge while being joined to the cutter blade piece 3. It is formed on the arcuate tip edge of the part.

The piercing blade 2T of the cutter blade piece 2 is developed symmetrically left and right around the mating surface of the cutter blade pieces 2 and 3 at the center of the cutting blades 2S and 3S.
The radius of curvature Rc of the arcuate tip edge of this piercing blade 2T is 30 mm, and its left-right width Wc is 20 mm.
The cutting edge of the piercing blade 2T is a round blade having a radius of curvature of 1 mm.

The corded rubber sheet material 50 is cut by the cutter blades 2 and 3 having the above shape.
Cutter blade pieces 2, 3 are used attached for example to the disconnecting device of the pair of left and right holders 11 and 21 as shown in FIG.

The holder 11 (12) is provided with a movable table 12 (22) that can be moved up and down and moved up and down and formed with a U-shaped tip, and front and rear side portions 12a, 12b (22a, 22a, 22) 22b) Two parallel guide shafts 13, 14 (23, 24) are installed between them, and the slider 15 (25) is slidably supported back and forth through the guide shafts 13, 14 (23, 24). Has been.
The cutter blade 2 is screwed down on the support plate 16 projecting from one slider 15 and the upper end is screwed downward, and the cutter blade 3 is projected from the support plate 26 projecting from the slider 25 on the other side. A part is screwed and it hangs down and is attached.

On the other hand, the rubber sheet material 50 has a strip shape, and a twisted cord 51 is embedded in parallel at substantially equal intervals (arrangement pitch Pcd) in the left-right width direction.
The thickness Dc of the cutter blade pieces 2 and 3 is smaller than the arrangement pitch Pcd (Dc <Pcd).
Referring to FIG. 4, the twisted cord 51 is configured by twisting a large number of steel or resin wires 52.

In FIG. 4, one wire 52 of the twisted cord 51 is indicated by a thick line, and the wire 52 is twisted and bent in a substantially spiral shape.
The curvature radius Rw of the wire 52 bent in a substantially spiral shape of the present twisted cord 51 is 24 mm, and the twist pitch Pw is 16 mm (see the thick line in FIG. 4).
Usually, the radius of curvature Rw of the wire 52 is 15 to 35 mm.

  When cutting the rubber sheet material 50 in which a large number of the above-described twisted cords 51 are arranged and embedded, as shown in FIGS. 3 and 5, the cutter blade pieces 2 held by the left and right holders 11 and 21 are used. 3 are located above the center of the rubber sheet material 50 in the left-right width direction in a state of being pressed and joined together.

When the movable bases 12 and 22 of the holders 11 and 21 are lowered, the joined and integrated cutter blade pieces 2 and 3 are pierced into the rubber sheet material 50.
When the cutting edge of the piercing blade 2T with a radius of curvature of 1 mm touches the rubber sheet material 50 and bites into the rubber sheet material 50, if the piercing blade 2T is in a position along one twisted cord 51, the piercing blade 2T is Since the cutter blades 2 and 3 are moved with high sensitivity by sliding of the slider 15 toward the weaker resistance, that is, the direction avoiding the twisted cord 51, the twisted cord 51 on the side close to the cutting edge bites into the twisted cord 51. Pierce avoiding 51.

Further, when the tip of the piercing blade 2T comes into contact with the rubber sheet material 50 and the piercing blade 2T is above the twisted cord 51, the radius of curvature Rc of the curved tip edge of the piercing blade 2T is 30 mm. There, constituting the twisted cord 51, twisted greater than 24mm radius of curvature Rw of the wire 52 that is curved in a substantially spiral shape (Rc> Rw), further width dimension Wc piercing blade, at 20 mm, twisted wire Since the twist pitch Pw of 52 is larger than 16 mm (Wc> Pw), the piercing blade 2T does not enter the twisted cord 51 (between the wires 52 and 52), and thus the cutter blade piece without breaking the twist. 2 and 3 can move to avoid the twisted cord 51, and the piercing blade 2T can be prevented from sticking into the rubber sheet material 50 while avoiding the twisted cord 51 and breaking the twist to cause the wire 52 to protrude. .

Since the cutter blade pieces 2 and 3 have a thickness Dc smaller than the arrangement pitch Pcd of the stranded cord 51, the cutter blade pieces 2 and 3 are smoothly inserted into the rubber sheet material 50 without being sandwiched between the adjacent stranded cords 51 and 51. Can penetrate.
As shown in FIG. 6, the cutter blade pieces 2 and 3 are formed so that the bent portions of the left and right cutting blades 2 </ b> S and 3 </ b> S bent in a dogleg shape penetrate to the depth reaching the rubber sheet material 50.

  Next, when the left and right movable platforms 12 and 12 are moved in the horizontal direction to the left and right, and the cutter blades 2 and 3 that have been joined are separated and separated from each other, as shown in FIG. The cutting blade 2S and the cutting blade 3S of the cutter blade 3 cut the rubber sheet material 20.

  The cutting blades 2S and 3S receive greater resistance from the twisted cord 51 on the side closer to the blade tip, and the cutter blade pieces 2 and 3 are more sensitive to sliding of the slider 15 in order to avoid the weaker cord, that is, the twisted cord 51. Since the cutting is performed while moving, it is possible to prevent a problem that the twisted cord 51 is scraped to be exposed or cut.

The rubber sheet material 50 thus cut does not expose the twisted cord 51 on the cut surface or protrude the wire 52, and maintains high product quality when used as a tire component or the like. Can do.
As a result of cutting the rubber sheet material 50 with a twisted cord using the cutter 1, the twist of the twisted cord 51 was not broken and the wire 52 did not protrude.

Thus, in order to satisfactorily cut the cords rubber sheet material 50 twist, the curvature radius Rc of the curved leading edge of the piercing blade 2T constitute the twisted cord 51, is curved in a substantially helically twisted It is necessary that the radius of curvature Rw of the wire 52 be larger.

However, even if the radius of curvature Rc of the piercing blade 2T is too large, the sharp angle of the blade when piercing the rubber sheet material 50 is lost, and the sharpness deteriorates in relation to the curvature radius Rw of the wire 52. The curvature radius Rc is set to be smaller than the length Rw + r obtained by adding the required length r to the curvature radius Rw of the wire 52.
Here, the required length r is 15 mm or less, and preferably about 10 mm.

  In the present embodiment, the required length r is 10 mm, the radius of curvature Rc of the piercing blade 2T is 30 mm, and the length 34 (= Rw + 10 = 24 + 10) obtained by adding the required length r to the radius of curvature Rw of the wire 52. When the radius of curvature Rc of the piercing blade 2T exceeds 39 (= Rw + 15 = 24 + 15) mm, the piercing blade 2T can be smoothly pierced and cut without losing the acute angle of the blade.

The cutter 1 used in the method according to the embodiment is such that the cutter blade piece 2 including the piercing blade 2T and the cutting blade 2S and the cutter blade piece 3 including the cutting blade 3S are opposite to the both cutting blades 2S and 3S. Since it consists of a pair of cutter blades 2 and 3 that are joined together in the direction and pierced into the central portion in the width direction of the rubber sheet material 50 and are separated and separated from each other, the twisted cord The containing rubber sheet material 50 can be cut efficiently and satisfactorily.

DESCRIPTION OF SYMBOLS 1 ... Cutter, 2 ... Cutter blade piece, 2S ... Cutting blade, 2T ... Piercing blade, 3 ... Cutter blade piece, 3S ... Cutting blade,
10 ... cutting device,
11 ... holding tool, 12 ... moving table, 13,14 ... guide shaft, 15 ... slider, 16 ... support plate,
21 ... holding tool, 22 ... moving table, 23,24 ... guide shaft, 25 ... slider, 26 ... support plate,
50 ... Rubber sheet material with twisted cord, 51 ... twisted cord, 52 ... wire.

Claims (5)

A cutter having an arc-shaped piercing blade at the tip edge and a cutting blade at the side edge is prepared, the piercing blade is pierced into a rubber sheet material containing a twisted cord, and the rubber sheet material is cut by the cutting blade to rubber. In a method for cutting a rubber sheet material with a twisted cord, cutting a sheet material,
A cutting method, wherein a radius of curvature (Rc) of a tip edge of the arcuate piercing blade is made larger than a radius of curvature (Rw) of a wire that is twisted to form the twisted cord and curved in a substantially spiral shape.   2. The method for cutting a rubber sheet material containing a twisted cord according to claim 1, wherein a width (Wc) of the piercing blade is larger than a twist pitch (Pw) of the twisted wire.   The radius of curvature (Rc) of the piercing blade is smaller than a length (Rw + r) obtained by adding a required length (r) of 15 mm or less to the radius of curvature (Rw) of the wire. 3. A method for cutting a rubber sheet material containing a twisted cord according to 2.   The rubber with twisted cord according to any one of claims 1 to 3, wherein a thickness (Dc) of the cutter is smaller than an arrangement pitch (Pcd) of twisted cords embedded in the rubber sheet material. Sheet material cutting method. The cutter includes a cutter blade piece including the piercing blade, the cutting blade, and a cutter blade piece including the cutting blade, which are joined together with the two cutting blades facing each other in the opposite direction. pierce direction central portion, spaced apart from claim 1 to any one twisted cords rubber sheet material cutting method according to claim 4, characterized in that you cut the rubber sheet material by separating from each other.

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