JPS63260428A - Manufacture of molding piece for connection such as branch saddle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a method for manufacturing connecting molded pieces, such as branch ends. In this case, the connecting profile is of the thermoplastic glass family and is equipped with a hot wire, which supplies an electric current to form a welded joint between the connecting profile and the connection object. It is in a format that can be used.

BACKGROUND OF THE INVENTION A method for producing a connecting molding of this type is known from European Patent Application No. 82401203.3.

In general, when connecting tubes of the thermoplastic glass family with connecting profiles by welding, connecting profiles with electrical heating elements in the form of spiral hot wires are often used. In order to form a welded joint between such a connecting piece and a tube, a current is supplied for a predetermined time by means of a spiral hot wire arranged on the surface of the connecting piece. The heat generation in the hot wire results in melting of the material of the connecting profile and of the surfaces facing each other of the tube.

According to the example of the European patent application, the fixation of the spiral hot wire is carried out by embedding the hot wire on one side of a disc. The inner end of the spirally embedded heating wire is bent and separated from the disk surface by a rotatable lip and guided out of the disk through the spiral winding. Both ends of the hot wire can thus be easily connected to a voltage source. However, this method has the following drawbacks. That is, at the point where the bent inner end of the hot wire and the spiral winding intersect, uneven heating conditions occur on the surfaces of the connecting piece and the tube facing each other, resulting in poor quality of the welded joint. It is severely damaged.

Problems to be Solved by the Invention The object of the invention is to improve the quality of welded joints in the method mentioned at the beginning.

Means for Solving the Problems The present invention has solved these problems as follows. In other words, one hot wire is placed on each side of one disk-shaped core.
The core, in which the hot wire is embedded in this way, is joined to the connecting piece, the core being made of a material which becomes integral with the material of the connecting piece by melting. According to this method, one heating wire is embedded in a spiral shape on each side of the disk-shaped core, and the inner ends of both heating wires are connected to each other at the center of the spiral. Can be done. It is also possible to embed a pair of hot wires in a spiral fashion, or to embed one hot wire successively on one surface of the core and then on the other surface.

The hot wire can also be embedded in one surface of each of the two disks, in which case both disks are joined into one core with their surfaces opposite the hot wire in contact with each other.

By selecting the type of hot wire embedding, it is possible to adapt the connecting profile to the respective heating requirements for optimum welded joint formation. The hot wire may be insulated and embedded, or may be embedded without insulation. When embedding the hot wire in a spiral shape, the pitch or number of the spiral windings may be different on both sides of the disc-shaped core, and the diameter of the hot wire itself may be changed. Alternatively, hot wires with different diameters may be used to embed them on both surfaces of the core,
The winding may be left-handed or right-handed.

In all possible embodiments of the inventive connecting molded piece, it is advantageous if the disc-shaped core is embedded with hot wires on both of its surfaces, thereby providing a permanent and high-quality In order to form a welded joint, a more uniform and complete melting of the disk-shaped core and the surface of the connecting piece adjoining this core or the surface of the object to be connected to the connecting piece is made possible.

The size of the spiral winding formed by embedding the hot wire is related to the size of the connecting molded piece and the surface on which the welded joint is to be formed on the object to be connected. As a result, different power is required depending on the size of the spiral winding to form an optimal welded joint. In the case of the example of the European patent application mentioned above, an electric welding tool for connecting tubes of the thermoplastic glass family is equipped with a hot wire and an auxiliary resistor connected in series with the hot wire. In order to define the total resistance of the hot wire and the auxiliary resistor, an electric control and metering device is connected to the electric welding tool, which automatically adjusts the resistance according to the measured total resistance. A current is introduced by the hot wire for a period of time that is precisely adjusted. In this case, the premise is that a constant total resistance value decreases in a constant period. This resistance measurement method is not accurate for systems that make automatic welding time adjustments in relation to the measured resistance.

This is because, depending on the electric welding tool used, the expansion of the connecting piece may be significantly different with respect to the hot wire, even if the expansion is the same.

This is because it has a resistance value of In this case, the tolerances of the resistivity of the hot wires will vary considerably, thus giving rise to different resistance values.

In order to cope with this point, in the case of the connection molded piece according to the invention, an auxiliary resistor is provided for the purpose of automatic processing of welding, and this auxiliary resistor is provided with a separate conductor, similar to the hot wire. via which it is connected to an electrical control and metering device. The resistance value of this auxiliary resistor can be precisely defined independently of the resistance of the hot wire, and can be applied to any manufacturing system for the connection molded piece according to the invention. In this case, for example, 1000hm or 10,000km
A specific resistance value of the auxiliary resistor of less than 00 hm or more corresponds to a predetermined welding time of, for example, 10 seconds or less than 600 seconds or more. The auxiliary resistor according to the invention can be installed either during or after the molding of the connecting piece.

According to a preferred embodiment, the auxiliary resistor is provided with a protective coating and is fastened to the connecting profile via a connecting pin. The welding time required to supply the desired power can be calculated by determining the resistance value of the hot wire of the connecting piece in relation to the resistivity and diameter tolerance of the wire material of the hot wire. Accordingly, a correct auxiliary resistor of corresponding resistance value can be mounted on the connecting profile. This auxiliary resistor serves to ensure that the required energy is supplied for a defined period of time during welding via an electrical control and metering device. This advantageously minimizes rejects of welded joints.

In order to be able to visually judge the progress of welding the connecting molded pieces, a hole is provided at an arbitrary location on the connecting molded piece, and the wall or bottom of this hole partially comes into contact with the hot wire. Loosely insert a pin with a mark made from a material different from the molded connection piece into the hole. This marked pin serves as an inspection element for the quality of the welded joint during welding. This is because the thermal expansion of the melting material will create an overpressure that will escape into the cavity and push out the pins within the cavity. The extent to which the pin is pushed out can be read by a mark that protrudes outside the well, and serves as a measure of the quality of the weld formed. This is because the amount of extrusion of the marked pin depends on the amount of melted material, which determines the thermal expansion of the fused area and thus the durability of the welded joint between the connecting profile and the connection object. It is from.

Embodiments The invention will now be explained according to embodiments shown in the drawings: FIGS. 1a, 1b and 1c show a disk-shaped core 1 in a plan view and in a longitudinal section.

A spiral hot wire 2 is embedded in both sides of the core 1. In the center of this disk 1, the inner ends bi and bi' of the hot wires 2 on both sides are connected to each other, so that when the voltage source is connected, the outer end bu of one hot wire is connected to the outside of the other hot wire. A current flows to the other end bu'. The pitch of the spiral winding of the hot wire 2 is selected depending on the amount of heating required, in which case the number of turns is 10 turns, less than 30 turns or more.

FIG. 2a shows a connecting profile 17 as a branch saddle in longitudinal section, and FIG. 2b shows it in cross section. The heating member, consisting of a disk-shaped core 1, has a hot wire 2 leading to an electrical connection pin 7, is bent so as to exhibit a bending radius that matches the radius of the connecting piece 3 to be formed, and is placed in a press mold. Or it can be positioned as an insert inside the mold. After the molding of the connecting molded piece 3, this heating element, i.e. the heating element made of a material whose disk-shaped core joins with the material of the connecting molded piece 3, together with the molded connecting molded piece 3, form one body. According to a further embodiment, a corresponding recess is formed in the connecting profile 3, into which the heating element is subsequently inserted.

An auxiliary resistor 4 is also shown in FIGS. 2a and 2b. This auxiliary resistor 4 has electrical connection pins 8 and
They can be placed at appropriate locations within the molded connection piece 3 when the molded connection piece 3 is molded, or they can be placed as a unit consisting of an electrical connection pin and an auxiliary resistor with a protective coating applied after molding.

A cavity 5 can also be seen in FIGS. 2a and 2b. This cavity 5 is formed during the molding of the connecting molded piece 3 via a suitable mold bottle of circular, oval, square or any other cross-sectional shape. After molding the connecting piece 3, a correspondingly produced pin 6 with markings is loosely inserted into this recess 5. A large number of such recesses 5 and mark pins 6 may be arranged if necessary.

[Brief explanation of drawings]

FIG. 1a is a plan view of a disk-shaped core according to the present invention, FIG.
1a is a longitudinal sectional view of the core shown in FIG. 1a, FIG. 1c is a bottom view of the core shown in FIG. 1a, FIG. 2a is a longitudinal sectional view of a molded piece for connection according to the present invention, and FIG. It is a cross-sectional view of a molded piece for use. 1... Core, 2... Hot wire, 3... Molded piece for connection,
4... Auxiliary resistor, 5... Hole, 6... Pin,
7, 8...Electrical connection pin-snap procedure amendment (method) September t'7, 1988

Claims (1)

[Claims] 1. A method for manufacturing a molded connection piece, the molded connection piece being made of thermoplastic plastic and equipped with a hot wire, which connects the molded connection piece and the object to be connected. In a device that can conduct a current to form a welded joint between Method 2 for manufacturing a molded piece for connection, characterized in that the disk-shaped core is made from a material that is integrated with the material of the molded piece for connection by melting. Embedded in the surface of each one side of the plate, both disks are brought into contact with each other on the surface opposite to the hot wire side, and are combined in the form of one disk-like core. Method 3: One auxiliary resistor is provided on the connection molded piece, and its resistance value can be preselected as a welding time parameter that is automatically adjusted before welding, and the resistance value and welding time can be preselected and adjusted. is controlled via an electrical control and metering device connected to the heating wire and the auxiliary resistor via a separate conductor between the voltage source and the connecting profile. or method 4 described in item 2, forming a cavity in the connection molded piece adjacent to the hot wire;
Claim 1: A marked pin made of a material different from the connecting molded piece is loosely inserted into this cavity.
The method described in any one of paragraphs to paragraphs 3 to 3.