WO2006014099A1

WO2006014099A1 - Die for electrically conductive line insulator pin

Info

Publication number: WO2006014099A1
Application number: PCT/MX2004/000057
Authority: WO
Inventors: Jesús Francisco LAU LAY
Original assignee: Lau Lay Jesus Francisco
Priority date: 2004-08-03
Filing date: 2004-08-03
Publication date: 2006-02-09

Abstract

The invention concerns the formula of a mixture of polyol and an isocyanate for making and bonding a die to the metal element of a pin. Said die is used as an insulating coupling element between a pin and an insulator on electrically conductive lines. The invention also concerns a fixing apparatus used in the method for making the die allowing the pin metal element to float in the mould, so that the die can be properly formed. The invention further concerns a method for making and bonding the die. Finally, the invention concerns a pin for insulators of the type used in electrically conductive lines, said pin being capable of being smooth or of comprising indentations between the metal body and the elastomeric die. The die exhibits excellent insulating properties, very high adherence to the pin, elastic properties and resistance to harsh weather conditions far superior than those of dies presently manufactured with lead or other synthetic materials.

Description

DEDAL FOR DRIVER LINE INSULATOR PROFILE

ELECTRICAL

BACKGROUND AND FIELD OF THE INVENTION

The present invention relates to thimbles for insulator pins in electrical conduction lines, also known in various countries as insulator sticks or as insulator pins. The pins for insulators are named as they are screwed on to them the ceramic insulators that will be the ones that support the overhead power lines. They are easily visible in the electricity poles as an auction, each insulator holding an electricity conduction line.

Patent (Dl) of the United States of America No. 5,413,443 refers to a method and apparatus for mounting an insulating thread to a pin of an electricity conduction line, in this patent an adhesive resinous material, such as an epoxy, is applied which is heat cured to a pin, which must also have a tapered end.

The present invention clearly differs from this patent because (Dl) consists of a threaded element (20), which is formed of a composite plastic to which molybdenum sulfate can be added as a lubricating powder. This plastic is not attached directly to the pin but rather To this end, a resin (32) is applied, in addition to this, Dl includes as part of the design of the threaded element elements (40) to prevent the sliding of the threaded element with respect to the resin (32) and the pin (18). The present invention specifically uses a polyurethane elastomer to make the thimble, which is attached directly to the pin and does not require the anti-slip or anti-rotation elements of Dl. There are other important differences such as the method of manufacturing the threaded element, such differences are evident to a person with average knowledge in the field.

United States of America Patent No. 4,973,798 (D2) refers to a rigid electrical insulator. In this patent a rigid head, made of a thermoplastic or thermosetting material, is applied to a stiffening element (1). The purpose of this head is to form a single element with the element (1) by applying an envelope (10) made of a thermosetting elastomeric material, which together will form the electrical insulator. The fixed head (7) is molded directly around the metal element (1). For this, the end (3) is provided with a notch (or some other type of machining).

The present invention is not intended to form an electrical insulator, nor to form the head (7) of D2 in order to accommodate a cable, nor does it use a notch or other mechanized work to achieve favor the adhesion between the threaded element of the present invention and the pin.

Patent 5,942,731 (D3) describes, among other products, a thimble constructed of high density polyethylene which does not adhere directly to the metal but a polymeric coating is applied.

The present invention directly applies the material that forms the thimble to the metallic element.

It is important to note, as evidenced by the aforementioned patents, that the electrical industry has sought to replace lead thimbles with a material that is friendly to the environment from its manufacture to its disposal, such as plastic that, however, does not Being biodegradable, if it represents a great advantage by not being so harmful either in its manufacture or at the end of its useful life.

BRIEF DESCRIPTION OF THE INVENTION

The present invention provides a thimble for adhering to a pin as a coupling element between this pin and a ceramic insulator, without the drawbacks of the state of the art thimbles, that is, constructed of a plastic material and directly attached to the element metal. The processes of application and elaboration that are carried out in the thimbles known until now, are substituted in the present invention, by a single process Novel and extremely simple. This thimble must be made of a non-conductive material of electricity, to prevent the risk of conduction between the metal rod and the ceramic insulator. In Mexico, they are specifically called pins in the Technical Specifications of the Federal Electricity Commission as well as in the Light and Strength Center. These pins have a thread molded in lead (The use of lead is an international practice) and the replacement of lead with a synthetic material (polyurethane elastomer, high impact polypropylene and other similar products) of greater impact resistance is proposed for facilitate its handling and avoid the problems that lead has as a highly polluting material, in addition to matching the low conductivity that lead has in electricity conduction applications.

A mixture is provided in the present invention for manufacturing and adhering the thimble, a clamping apparatus for keeping the metal body of the pin floating and forming the thimble in its entirety, a method is also provided for manufacturing and adhering the thimble, to finally provide a pin for insulators of electricity lines, which comprise a conventional metal body and a threaded thimble, characterized by the latter, because the metal body may or may not have notches at the end where the thimble is to adhere . BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a side elevation view of the pin that includes the novel thimble.

Figure 2 is a detail view of the thimble attached to the pin, partially in section.

Figure 3 is a schematic diagram of the apparatus for manufacturing the thimble.

Figure 4 is a schematic diagram of the arrangement of the devices used in the thimble manufacturing process.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a novel thimble used in pins for electrical insulators in high voltage lines, built on a polyurethane elastomer.

Figure 1 shows, schematically, this pin (1), with the thimble (2) assembled to its metal body (3), being able to clearly observe the threaded end (4) that will be used to fix the pin (1) to the poles that hold the power lines. In this schematic representation, it is appreciated that the construction of the pin is simple in regard to its union with the thimble.

Figure 2 shows an additional detail, the metal element (3) of the pin has no notches, nor any special formation to facilitate the anchoring of the thimble (2), this in itself constitutes an extra advantage of the thimble (2) of the present invention and its method of application to the metallic element (3), on the other hand, it can be seen that the upper part (e) has a thickness that is adjustable during the thimble manufacturing process (2), so that if additional insulation is desired in the upper part of the pin (1), it will be enough to increase the thickness of (e) to (e ').

As mentioned above, the drawbacks of the state of the art when preparing a thimble and subsequently applying it to the pin are solved by the present invention by manufacturing the thimble (2) and applying it to the metallic element (3) at the same time and in a single step. .

The present invention requires a fastener for the process of manufacturing and adhering the thimble (2) to the pin (1), as seen in Figure 3, which is constituted by a backrest (9) attached to a base ( 8), the backrest (9) being longer than the base (8) and its length depends on the size of the pin being worked. Placed perpendicular to the backrest (9) two stabilizer supports (12) are located whose function is to guide the pin (1) for its correct placement in the mold (10). To give the thickness (e), a support body (6) is used on which the washer (7) of the metal body (3) rests. To hold the pin (1) in position, a clamp (5) and its screw (11) or some similar device.

This clamping device is presented as a representative unit but can be replicated in as many multiples as necessary, that is, the base could be of sufficient size to accommodate 2, 4, 8 or more pins as required by the volume of production.

The method for manufacturing and adhering the thimble (2) to the pin (1), comprises the following steps: 1. Prepare and properly clean the metal body (3) at the unthreaded end thereof, which is where the thimble will be placed (2) .

2. Firmly hold the metal element (3) on the base of the fastener described above, so that it is floating in relation to the circular mold (10) on all its sides, the circular mold (10) is a cylinder with a single upper opening where the pin (1) is inserted. A minimum distance of 2 millimeters must be kept between the unthreaded end of the metal body (3) and the base of the cylindrical mold (10), although as mentioned before the thickness of the upper part (e) is adjustable and it will be enough to hold the metal body (3) at a greater distance from the base of the cylindrical mold (10) so that the thimble conformation is thicker in its upper part. 3. Combine in the device shown in Fig. 4

Isocyanate and Polyol directly in the latex mold (10). 4. Allow the polyol and isocyanate mixture to perform the gelation process and reach the necessary hardness to be able to unmold the thimble (2),

5. Allow the thimble (2) demoulded to cure at room temperature until it reaches its maximum hardness.

A mechanism for emptying into the mold (10) the mixture of the polyol and the isocyanate is shown schematically

In said figure 4, (13) and (14) represent the reservoir containing the polyol and the isocyanate, respectively. By dragging a flow of inert gas (21), the polyol and isocyanate are conducted through the pipes (15) and (16) to corresponding metering pumps (17) and (18). These elements are mixed in a static mixer (19) just before being emptied into the mold (10) by means of the direct injection gun (20).

With the equipment and method mentioned above, the thimble (2) while being molded adheres to the metallic element (3), reducing one or more steps in the application of the thimble with respect to what is known in the state of the art. Obviously this procedure has several advantages, the first is that injection machines are not required since the components are simply emptied into the mold (10), nor is additional equipment required to heat treat the formed material and cure it, nor requires additional steps such as Remove the thimble (2) from the mold (10) and take it to another location to apply it to the metal element (3).

As already mentioned, the thimble (2) is manufactured with a polyurethane elastomer to thereby replace the use of lead.

The elastomer is made by mixing or combining two chemical components in the following proportions: a.- 32.3% - 38.3% isocyanate and a 61.7% - 67.7% Polyol. b.- Isocyanate in 33.3% - 36.8% and a polyol in a proportion of 63.2 - 66.7%. c- The optimum mixture obtained consists of an isocyanate in a proportion of 33.3% - to 34.3% and the polyol in a proportion of 65.7% to 66.7%.

A catalyst can be added to the aforementioned mixtures in order to accelerate the reaction, according to the specific characteristics of the molds (10), in order to allow the exit of air bubbles that could be trapped inside the molds. molds (10) during the filling and gelation process.

These chemical components, when mixed produce an exothermic reaction and chemically combine to produce a polyurethane elastomer. In general it is a high impact polymer. With respect to the mold (10), it is not metallic to prevent a thermal shock that prevents the chemical reaction of the elastomer from occurring at the time of the exothermic reaction of the chemicals mentioned above. In the present case, the molds (10) are manufactured with a type of temperature-resistant latex that is generated during the reaction, to prolong the life of the same. Another selection criterion was the economic one because this type of mold is less expensive than the metallic one. The thimble (2) thus formed is not injected, the respective components are simply emptied into the mold (10).

By reading the present description, people with average knowledge in the field will be able to realize that modifications and improvements can be made to the present invention, such as the use of new and more modern feeding devices of the polyol and the isocyanate to the mold ( 10) or new and more modern dispensers, or apparatus for handling the molds, and mixing and emptying in an automated manner, all of which are considered included in the scope of the appended claims.

Claims

1.- A mixture to manufacture thimbles for a pin used in insulators of power lines, characterized in that it consists of:

- Isocyanate 32.3 - 38.3%

- Polyol 61.7 - 67.7%

2.- A mixture for manufacturing thimbles, according to clause 1, characterized in that the Isocyanate is in a range of 33.3 - 36.8% and the Polyol of 63.2 - 66.7%

3.- A mixture according to clause 2, characterized in that the concentrations of its components are as follows: Isocyanate 33.3 - 34.3%

Polyol 65.7 - 66.7%

4.- An apparatus for manufacturing and adhering a thimble on a pin used in insulators of power lines, characterized in that it comprises the following parts: a.- A vertical backrest as long as required according to the size of the metallic element of the pin , which holds all the pin fastening accessories, b.- A horizontal base perpendicular to the backrest, where a mold is placed, C- Two stabilizing supports perpendicular to the backrest, which serve as counterpart of the clamp, d.- A support body on which the metal body washer rests, e.- a clamp and its clamping screw, to apply pressure on the metal body against the stabilizing supports, f.- a latex mold in which the thimble will be formed,

5.- A method to manufacture and adhere a thimble on a pin used for insulators of power lines, characterized in that it contains the following stages: a.- Prepare and properly clean the metal body, at the upper end of it where it The thimble will be placed, b.- Hold the metal element firmly in an apparatus according to claim 4, so that it is floating in relation to the circular mold, c- Combine the polyol and isocyanate according to claims 1, 2 and 3, through a static mixer and empty said mixture directly into the circular latex mold. d.- allow the mixture to perform the gelation process and reach the necessary hardness to be able to unmold the thimble, e. allow the demoulded thimble to cure at room temperature until it reaches its maximum hardness.

6. A threaded thimble for pin of insulators of electricity lines, characterized in that it is obtained by the method of claim 5.

7.- A pin for insulators of electricity lines, of which they comprise a conventional metal body, a washer, a threaded end with its nut to fix it to the pole that holds the electricity lines and a threaded thimble that must be introduce into the ceramic insulators on which the electricity lines are supported, characterized in that the metal body is smooth at the end where the thimble mentioned in claim 6 is to be adhered.

8. A pin according to claim 7, characterized in that the metal element can have notches or any other physical anchoring element, at the end where the thimble is to be adhered, to use the existing or conventional metal bodies.