JPH01186715A - Manufacture of lighting glass and forming iron - Google Patents

Abstract

PURPOSE:To make it possible to integrally form an insulated supporting barrel for containing a lighting element in an insulator by press-forming from a back face of a precompact with a forming iron made of a permeable material having a cylindrical convex for forming the insulated supporting barrel. CONSTITUTION:Ash 30 supplied into a forming die 5 is formed by revolving press forming with a preforming iron 10 having an irregularity 9 for forming a concentric rib to uniformly preform a suspension insulator at its back. After that, the insulator is simultaneously and integrally press-formed into a last configuration having the rib and an insulated supporting barrel by an unrevolving forming iron having a cylindrical projection 15 for forming the insulated supporting barrel. Accordingly, a lighting insulator having the insulated supporting barrel containing a lighting element is easily monolithically formed.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for forming a lightning arrester, such as a suspension type, which is provided with an insulating support tube for incorporating a lightning arrester element into a cap, and a forming iron used therefor. It is related to.

(Prior art) In order to prevent the insulator device from being destroyed by high voltage when lightning strikes a power transmission line, etc., a lightning arrester element with voltage non-linearity whose main component is zinc oxide etc. is placed in parallel with a single insulator. It is already known that the lightning arrester is placed on the ground to allow the lightning voltage to escape to the ground (for example, Publication of Utility Model Publication No. 61-31456). Conventionally, it has been common for such lightning arrester elements to be installed separately from the insulator. However, recently, attempts have been made to incorporate lightning arresting elements into insulator hats. However, in this case, it is necessary to provide an insulating support tube in the insulator cap to house the lightning arrester, so holes are punched out of raw material into the insulator cap, which has been rotary press-molded using a molding trowel called a nine-trowel. The method used is to polish the holes after firing, then fit an insulating support tube formed and fired in a separate process into the holes, apply a glaze, etc., and re-fire to join. However, the process is complicated and the manufacturing cost is high.

(Problems to be Solved by the Invention) The present invention solves the conventional problems as described above, and simplifies molding by integrally molding an insulating support tube for storing a lightning arrester into an insulator body such as a suspension insulator. This invention was completed in order to provide a method for molding a lightning arrester insulator that can reduce the manufacturing cost and the molding trowel used in the method.

(Means for Solving the Problems) The present invention supplies clay into a mold, performs rotary press molding with a preforming iron having concentric lip molding unevenness, and then preforms the shape of the back surface of the insulator. Press molding is performed from the back side of the preform using a non-rotating molding iron made of an air-permeable material having a cylindrical protrusion for forming an insulating support tube, and simultaneously integrates it into a final shape with a lip and an insulating support tube. A first invention relating to a method for molding a lightning arrester, which is characterized in that it has a protrusion for forming a pin insertion hole in the center, and preferably a plurality of protrusions for forming an insulating support tube are evenly distributed around the protrusion. A second invention relating to a molding trowel for a lightning arrester, characterized in that a trowel body made of a breathable material and having a cylindrical protrusion and an arcuate recess for lip molding is attached to the lower surface of a substrate with a gap provided therein. It consists of.

(Example) Next, to explain the process of forming a suspended insulator, which is an example of the present invention, as shown in FIG. Rotary press molding is performed using a mold (2).The lower mold has a gently raised part (3) on its upper surface, and the upper mold (2) has a recessed part (4) that roughly corresponds to the shape of the upper surface of the suspended insulator. To explain the molding method in terms of the firing iron molding method, the upper mold (2) is heated to several hundred degrees Celsius, and the moist clay (30) is heated in the high-temperature upper mold (2). Rapidly solidify while pressing the surface.
Obtaining a disc-shaped clay (30) as shown in the figure. Next, as shown in Figure 4, such a disc-shaped clay (30) is placed inside the mold (5). After supplying the material, it is pressed using a preliminary presser trowel (6). The preliminary presser foot (6) is equipped with a raised part (7) that is larger than the raised part (3) of the lower die (1) and a flat plate part (8), as shown by the imaginary line in FIG. The mold (5) containing the zero-order clay (30) is pressed so that the peripheral edge part slightly protrudes from the peripheral edge of the mold (5), and the upper surface, that is, the surface part of the suspended insulator is molded into the final shape. As shown in Figure 5, preforming is provided with concentric concave and convex grooves (9) for forming ribs on the back of the insulator!
Move it directly under la. and preform! The unevenness (9) of the preforming trowel α0, which performs rotary press molding while rotating the JI Ql, has a shape that is closer to the shape of the back surface of the suspension insulator than the raised portion (7) of the preforming trowel (61). By this rotary press molding using preforming!lQl, the clay (30) in the mold (5) is preformed into a shape close to that of the back surface of the suspended insulator.

The mold (5) containing the clay (30) preformed in this way is then moved to a non-rotating molding iron (11) having a cylindrical protrusion for molding an insulating support cylinder, as shown in FIG. will be moved directly below. Molding 1N (11) is an iron body (13) attached to the bottom surface of a substrate (12), as shown enlarged in Fig. 1, and this iron body (13) has a pin insertion hole formed in its center. A cylindrical protrusion (15) for forming an insulating support cylinder and an arcuate recess (16) for forming a rib, preferably 2 to 4 concentrically spaced protrusions (14) for forming the insulation support tube, are provided. As shown in FIG. 8, the suspension type lightning arrester (40) molded in this embodiment has an insulating support tube (41) integrated with the lip (42) in the center of the shade. Since the trowel body (13) has a shape corresponding to this, the relative positions of the insulating support tube (41) and the lip (42) are as shown in FIG. 9 as an example. Various design changes can be made to the iron body (
It goes without saying that the arrangement of the cylindrical protrusion (15) and the arcuate recess (16) in 13) will also be changed accordingly.
Further, the iron body (13) is made of a breathable material having communicating pores in which inorganic particles are bonded with synthetic resin, etc.
A molded surface layer in which fine inorganic particles having micropores of preferably 10 μm or less are bound together with an organic binder, and a lower layer in which inorganic particles having a pore diameter of 50 to 200 μm that maintain mechanical strength are bound together with a binder. The iron body (13), which is particularly preferably of a heavy structure, is airtightly attached to the lower surface of the substrate (12) with a gap (17) as shown in FIG. Before using the substrate (
12) while sucking air through the through hole (18),
Further, during mold release, air is blown through the through hole (18) to cause a mold release agent to bubble out on the surface of the iron, thereby facilitating mold release. Note that (19) is an O-ring for maintaining airtightness.

The molding iron (11) described above descends toward the preformed mold (30) inside the mold (5) without being rotated, and as shown in FIG. The final shape of the insulator is simultaneously press-molded into the final shape of the insulator, which has an insulating support tube and ribs for storing the lightning arrester. Also, during pressing, voids (1
Since the inside of the breathable iron body (13) is reduced in pressure through 7), deep rib parts can be accurately molded, and when demolding, the inside of the iron body (13) is pressurized to improve mold release properties. Moreover, since the surface of the clay (30) has been shaped in advance to a shape close to the back surface of the suspension insulator, the final press forming with the forming trowel (11) can be carried out easily, and at the same time, the peripheral part The protruding portion is cut off. After that, turn the molding iron (11) upside down and take out the molded product as shown in Figure 7.
3), preferably having a plurality of ribs (42) around it
A suspended lightning arrester is obtained in which the insulating support tube (41) and the insulating support tube (41) are integrally molded.

Note that the present invention is not limited to suspended insulators, but can also be applied to other insulators.

(Effects of the Invention) As described above, according to the first invention of the present application, the clay supplied into the mold is rotary press-molded using a preforming trowel equipped with concentric rib-forming unevenness to form a suspended insulator. After pre-forming the back surface uniformly, the final shape with ribs and the insulating support tube is simultaneously press-molded using a non-rotating molding iron having a cylindrical protrusion for forming the insulating support tube. , the surface of the clay is gradually molded into the final shape without any difficulty. As a result, according to the method of the present invention, unlike the conventional method in which the insulator body and the insulating support tube are manufactured in separate processes and then joined by glaze or the like, the lightning arrester has the insulating support tube that houses the lightning arrester element. This makes it easy to integrally mold the insulator.

Furthermore, by using the molding iron of the second invention of the present application, the pin insertion hole, the rib, and the insulating support tube can be molded into one body at the same time, and
By blowing air into the air-permeable trowel body through the gap between it and the substrate when releasing the molded object, or conversely by suctioning air during molding, air can accumulate even in the uneven parts for deep lip molding. It is possible to perform accurate molding without causing molding defects due to molding, and it is also possible to perform reliable mold release. Therefore, the present invention greatly contributes to the development of industry as a method and molding trowel for lightning arrester insulators that eliminate the problems of the conventional methods.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the molding trowel according to the second invention of the present application, FIGS. 2 to 7 are cross-sectional views showing the molding process of the first invention of the present application, and FIG. FIG. 9 is a partially cutaway perspective view of another suspension type lightning arrester molded according to the present invention. (5): Molding die, (9): unevenness for lip molding, αI: preforming trowel 4, (11): molding trowel, (12): substrate, (
13) : Trowel body, (14) : Projection, (15) : Cylindrical projection, (16) + arcuate recess, (17) : Gap. Patent applicant: Tokyo Electric Power Company, Inc., Nippon Insulator Co., Ltd. Representative: Akira Shima Buma
Watanuki Tatsu interlayer
Fumi Yamamoto Figure 1 Figure 2 Figure 3 Figure 6 Figure F Figure 8 Figure 9rl! A

Claims (1)

[Scope of Claims] 1. Clay is supplied into a mold and rotary press-molded using a pre-forming trowel equipped with concentric rib-forming unevenness to pre-form the shape of the back surface of the insulator, and then an insulating support tube is formed. Press molding is performed from the back side of the preform using a non-rotating molding iron made of a breathable material having a cylindrical protrusion for molding, thereby simultaneously molding the preform into a final shape comprising ribs and an insulating support tube. Characteristic molding method of lightning arrester. 2. The iron body is made of a breathable material and has a protrusion in the center for forming a pin insertion hole, a cylindrical protrusion for forming an insulating support tube, and an arcuate recess for forming a rib around the protrusion, and is attached to the substrate. A molding trowel for a lightning arrester, characterized in that it is mounted with a gap provided on the underside of the lightning arrester.