JPS61252969A - Manufacture of endless packing and apparatus thereof - Google Patents

Abstract

PURPOSE:To prevent the deterioration of the sealing performance by alternately forming the perfect cut parts and the imperfect cut parts on a cylindrical material having a plane shape same to an endless packing as manufacturing object. CONSTITUTION:A cylindrical material 5 is wound onto two rotary shafts arranged nearly in parallel and cut by a cutting tool 7. Onto the peripheral surface of one rotary shaft 1 having a relief groove 2 formed, a small-radius peripheral surface 3 whose radius is gradually reduced and again increased gradually is formed, and the rest is formed as a large-radius peripheral surface 4 having the equal radius. Therefore, onto the cylindrical material worked by this manufacturing apparatus, the perfectly cut parts and the imperfectly cut parts are formed alternately. Therefore, cut parts and projection are not formed when the endless packing pieces are separated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for manufacturing an endless packing, and more particularly to a method and apparatus for manufacturing an endless packing whose end surfaces are parallel to each other.

(Prior art) As a means of manufacturing an endless packing made of a rubber-like elastic material with high efficiency, a cylindrical material having the same planar shape as the endless packing is molded, and the cylindrical material is attached to a rotating shaft. A method is known in which a product is obtained by applying rotational motion by extrapolation or wrapping and cutting with a cutting tool.

The one shown in Fig. 5 is an example of the manufacturing method of this type of endless packing that has been conventionally used. A cylindrical material (5) formed to have the same planar shape as the endless packing is extrapolated onto the rotating shaft (1) arranged at a pitch equal to the width of the packing, and the rotating shaft (1) is The cutting tool (1) is sent inward in the radial direction during rotation, and an endless packing is produced by complete cutting.

When the endless packing is long, a method is used in which two rotating shafts are arranged approximately parallel to each other, a cylindrical material is wrapped around both wheels, one of the rotating shafts is driven, and the endless packing is separated using a cutting tool. ing.

(Problems to be Solved by the Invention) In the method for manufacturing an endless packing according to the prior art described above, as the cutting progresses, one side of the cylindrical material (5
) supported by the cutting tool (7) pushes the endless packing piece to be separated in the axial direction to cause lateral displacement.
Problems such as the cut surface not being formed into an accurate plane, particularly on the inner peripheral side, or variations in width dimension, cause a problem in that the sealing performance of the endless packing is significantly reduced.

In order to solve the above-mentioned problem at the end point of cutting, one of the inventors proposed that, as shown in FIG. devised a manufacturing method in which they were removed from the rotating shaft in a state in which they were connected to each other by the thin inner walls, and separated by hand, etc., and were able to achieve a certain purpose (Japanese Patent Application Laid-Open No. 57-6
(See Publication No. 6088).

However, in this method, when separating the inner thin-walled parts, a protrusion (9) is attached to one side of the endless packings adjacent to each other as shown in the figure, and a notch (10) is attached to the other side.
This caused a problem in that the sealing performance of the endless packing could be degraded.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a method and apparatus for manufacturing an endless packing having an accurate rectangular cross-sectional shape.

(Means for Solving the Problems) In view of the problems in the endless packing manufacturing means according to the prior art described above, the present invention provides a method for cutting into a cylindrical material with a cutting tool so that the total thickness of the cylindrical material is completely cut. The endless packing pieces connected to each other by the intermittent thin-walled portions are removed from the rotating shaft, so that the portions cut into a thin wall and the portions that are incompletely cut while leaving a thin wall are alternately formed.
Each endless packing is formed by separating thin-walled parts.

As a means for making cuts in which completely cut parts and incompletely cut parts are arranged alternately, at least one part of the circumferential surface of the rotating shaft into which the cutting tool is cut is formed to have a smaller radius than other parts. The cam mechanism, crank, This is accomplished by arranging a mechanism or the like to change the distance between the cutting tool and the rotating shaft during the rotational movement of the cylindrical material.

(Function) According to the method for producing an endless packing of the present invention, parts where the entire thickness of the cylindrical material is completely cut and parts where the thickness is incompletely cut are formed alternately. For example, the formation of the thin part is limited to a part of the entire length of the endless packing, and its cross-sectional area becomes narrow, but the endless packing to be cut is not separated from the cylindrical material throughout the entire cutting process.

In the endless packing manufacturing apparatus of the present invention, in which a part of the curved surface of the rotating shaft on which the cylindrical material is inserted or wrapped is formed to have a smaller radius than the other part, the cutting edge is inserted into the clearance groove. The cutting tool completely cuts the part of the cylindrical material supported by the large radius circumference of the rotating shaft, and the part of the cylindrical material supported by the small radius periphery of the rotating shaft is formed with sharp edges at both ends. Cuts incompletely, leaving a thin wall.

(Example) In the example shown in Fig. 1, a cylindrical material (5) is wound around two rotating shafts arranged approximately parallel to each other, and cut by a cutting tool (7). As shown on the right side of the drawing, a small radius circumferential surface (3) whose radial dimension gradually decreases and then gradually increases again is attached to the circumferential surface of one rotating shaft (1) which is driven by means not shown. is formed, and the remainder is formed as a large radius circumferential surface (4) having the same radius.

In the cylindrical material processed by the manufacturing apparatus shown in FIG. 1, completely cut portions (11) and incompletely cut portions (12) are formed alternately, as shown in FIG. 2.

In the embodiment shown in Fig. 3, a small radius circumferential surface (3) made of a concave curve is formed at two places on the circumferential surface of the rotating shaft (1), and the other portions are left as a large radius circumferential surface (4). It is.

The embodiment shown in FIG. 4 has a small radius circumferential surface (3) and a large radius circumferential surface (
4).

(Effect of the invention) As described above, the method for producing an endless packing of the present invention,
The cylindrical material, which has the same planar shape as the endless packing to be manufactured, is configured to alternately form completely cut parts and incompletely cut parts, so that each endless packing piece can be easily cut during the cutting process. Since it does not completely separate from the cylindrical material even at the final stage, defects such as the cut surface being formed at an angle, which were observed in the conventional manufacturing method in which each endless packing piece was completely separated, are prevented. Since the endless packing pieces are connected to each other only by thin uncut portions having a narrow cross-sectional area, no chips or protrusions are observed when the endless packing pieces are separated from each other.

The endless packing manufacturing apparatus of the present invention has a structure in which a small radius circumferential surface is formed on a part of the circumferential surface of the rotating shaft on which the cylindrical material is inserted or wrapped, so that the large radius circumferential surface can be formed on a large radius circumferential surface. The supported part of the cylindrical material is completely cut, and the part of the cylindrical material supported by the small radius circumferential surface is incompletely cut, so that an alternating arrangement of completely cut parts and incompletely cut parts is created. brought from.

[Brief explanation of the drawing]

FIG. 1 is a plan view and a partial side view of an embodiment of the endless packing manufacturing apparatus of the present invention, and FIG. 2 shows the processing steps of the endless packing manufacturing method of the present invention using the manufacturing apparatus of FIG. 3 and 4 are side views showing other embodiments of the endless packing manufacturing apparatus of the present invention, and FIG. 5 is a side view showing the conventional endless packing manufacturing apparatus and its manufacturing apparatus. FIG. 6 is a cross-sectional view showing a manufacturing method using the apparatus, and a perspective view showing another example of a method for manufacturing an endless packing according to the prior art. DESCRIPTION OF SYMBOLS 1... Rotating shaft, 2... Relief groove, 3... Small radius circumferential surface, 4... Large radius circumferential surface, 5... Cylindrical material, 7
...Cutting tool, 9...Protrusion, 10...Chip,
11... Completely cut portion, 12... Incompletely cut portion.

Claims (1)

[Claims] 1. In a method of manufacturing an endless packing by molding a cylindrical material having the same planar shape as an endless packing and cutting the cylindrical material, the entire thickness of the cylindrical material is completely reduced. 1. A method for manufacturing an endless packing, characterized in that portions cut in half and portions cut incompletely leaving a thin wall are alternately formed. 2. In an apparatus for manufacturing an endless packing by cutting a cylindrical material having the same planar shape as the endless packing, the peripheral surface of the rotating shaft around which the cylindrical material is inserted or wrapped has a different radius dimension. A manufacturing device for endless packing, characterized in that: 3. The endless packing manufacturing apparatus according to claim 2, wherein the rotation axis is one axis. 4. The endless packing manufacturing apparatus according to claim 2, wherein the rotation axes are two axes arranged substantially parallel to each other.