JPH0262379B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a heating device made of a plastic material (in particular a thermoplastic material) in which holes are formed in an element made of a similar or equivalent plastic material. Concerning the structures used to create and how to use this apparatus.

Although the structure according to the invention can be used, for example, to create holes in once-buried elements, its primary use is in the construction of pipes made of plastic materials, in particular thermoplastic materials. The purpose is to embed a branch pipe connector in the pipe.

(Prior Art/Problem to be Solved by the Invention) Generally, this type of branch pipe connection is performed by drilling a hole in the main pipe after placing the branch pipe connector, and this hole is made of thermoplastic material. This is done by heating the part of the main conduit to be drilled with a heating electric resistor.

In this kind of known conventional heating device, the heating electric resistor is enclosed in the saddle of a branch pipe connector installed in the main pipe section at the location where the connection is to be made. Heat the zone. In this case, the branch pipe connector and the main pipe must be welded and sealed at the same time by this heating.

Known devices for this type of heating are constructed by winding a heating wire precoated with an insulating sheath into a spiral and then embedding it in a generally circular section of the saddle for attachment to the external surface of the main conduit. has been done. However, the production of this type of insulated wire helix and its embedding in the saddle are expensive and difficult operations, and are not suitable for mass production, especially if good quality is desired.

Furthermore, since one end of the helical body for connecting to the heating power source is located at the innermost end of the spiral winding, this end must be passed through the inside of the pipe of the branch pipe connector to connect the power source. Therefore, the work becomes complicated.

In another known proposal, a rectangular net of heating wire coated with a sheath is fixed inside the branch pipe fitting and is placed over the main pipe and held between the branch pipe fitting and the main pipe. Then, the branch pipe connector is pressed against the main pipe using a clamp so as to obtain the crimping force necessary for attachment, and electricity is applied to heat the wire. The main pipe is then perforated as soon as the wall of the main pipe reaches a sufficient viscosity.

However, with this method, the entire outer circumference of the main pipe is heated, so a large voltage is required for welding, and the plastic material that makes up the main pipe needs to be softened, so there is a risk that the main pipe may split. There is. Moreover, during the drilling of the main conduit, it is necessary to cut a large number of wires of the rectangular net, which complicates the operation and may even lead to micro-leakage along the plane of the heating wire from which the sheath has separated.

(Means for Solving the Problem) In order to eliminate the above-mentioned drawbacks, the object of the present invention is to:
A structure composed of a plate having a relatively thin thickness, an opening in the center, and a spiral groove on one side, the heating wire being able to be accommodated in the spiral groove, and the groove being provided. One end of the wire can be locked to a first projection installed on the surface of the plate, and the other end of the wire can be locked to a similar second projection located away from the first projection. The purpose is to create a structure of the type mentioned at the beginning.

A first embodiment of a structure of this type is characterized in that the plate is substantially circular and has two ears carrying said projection, and the outer turn of the helical groove is located at the position of said first projection. The plate is opened on the peripheral surface of the plate, and the plate is provided with a tongue piece at the position of the ear that supports the second protrusion, and the tongue piece is bent onto the side of the plate with the groove. When the wire end passes through a radial position, at least a portion thereof is adapted to act as an insulating support between the wire end exiting the inner turn of the groove and reaching and locking the second protrusion. Features.

In another embodiment, the plate is provided with a wire guide claw that engages with the first protrusion at the position of the outer peripheral opening of the groove, and/or the plate is provided with a wire guide claw that engages with the first protrusion, and/or the plate is provided with a wire guide claw that engages with the first protrusion, and/or a wire guide claw that engages with the first protrusion is provided on the upper surface of the bent tongue. A feature is that a claw is provided to guide the wire that is locked to the two protrusions.

Yet another embodiment provides that (a) the tongue includes a thin section near the periphery of the plate forming a folded portion, and (b) the periphery of the plate includes between two protrusions: at least one locating projection is provided, (c) each projection has a conical base coupled to the groove mounting surface of the plate and terminates in a cylindrical portion; (d) the sides of the spiral groove are arranged such that: (e) the width of the groove is smaller than the diameter of the heating wire over at least a certain length of the groove;

In the structure of the present invention, a heating wire can be easily installed in the helical groove. For example, a heating wire pulled out from a bobbin is locked to the first protrusion, wrapped around an adjacent claw, a cross member having a plurality of legs extending between the two protrusions is placed at the center of the plate, and the cross member is Rotate the lower plate to fully load the heating wire, fold the tongue over the plate, cut the wire, and pass the cut end of the wire between the tabs carried on the tongue. This can be done by locking onto two protrusions.

After carrying out the above operations, it is advantageous if the mouth of the groove is deformed by crimping a hot tool and the heating wire is enclosed within the groove.

The invention further relates to a method of using a heating device obtained from the above structure for securing a saddle of a branch pipe coupling to a main pipe made of plastic material.
This method preferably involves embedding the above device in a curved state on the surface of the saddle that is to be fixed to the main pipe when forming the saddle, and locking the U-shaped hook to the leg of the saddle while heating the wire. The saddle portion is firmly held in the conduit by locking a half ring including an inclined locking groove to the leg, or by a tightening action due to elastic deformation of the half ring and/or the saddle portion. Features.

<Examples> The present invention will be described below with reference to the accompanying drawings showing examples.

As can be seen from FIGS. 1 and 2, the structure according to the invention consists of a cast, substantially circular, thin plate 1 of plastics material. In the upper surface 2 of this plate 1, grooves generally indicated by 3 are formed simultaneously with the casting of the plate 1. The outer turns 4 of the grooves are preferably open to the peripheral surface of the plate at wide grooves 5 provided with tabs 5', so that they can be easily demolded by simply rotating the plate in its own plane. can. At the position of this wide groove 5, a first ear 6 extends from the plate 1. This lug 6 has integrally molded therein a first projection 7 which is substantially trapezoidal in shape and has a bottom 8 and a cylindrical top 9 . The plate 1 is provided with a second lug 6' diametrically opposite to the lug 6, and this lug 6' is provided with a second projection 10 identical to the first projection 7. A curved tongue piece 12 is connected to the second protrusion 10 via a thin portion 11 that is a bent portion. This portion 13 of the tongue piece 12 is the tongue piece 1
2 assumes a diametrical position substantially aligned with the projections 7, 10 and the inner winding end 14 of the groove 3. On the back side of the portion 13 of this tongue piece 12, there are 2
Rows of tabs 15, 15' (FIG. 5) are provided.
Furthermore, the peripheral edge of the plate 1 is provided with four positioning projections 16, 17, 18, 19 (which will be explained below). The depth of the groove 3 is such that the heating wire 3' accommodated in the exposed state is
It is selected to be located as close as possible to the surface of the plate 1 opposite to the surface on which the groove 3 is provided.

When installing the heating wire 3' in the groove 3,
Operate as below. Heating wire 3' (Figure 3)
is pulled out from the storage bobbin 20, the free end of the wire 3' is wound around the projection 7 (FIG. 4), and the wire 3' is then passed around the pawl 5' and placed at the entrance of the helical groove 3. Next, a cross member 21 having four legs is placed so as to press the plate 1 at the center of the plate 1, and the plate 1 is rotated clockwise to insert the wire 3' drawn out from the bobbin 20 into the spiral groove 3. Gradually load inside. Once the wire 3' is loaded up to the winding end 14 inside the groove 3,
Carefully remove the cross member 21 so that the wire 3' does not protrude from the groove 3, and thin the curved tongues 12, 13 so that the portion 13 is at a diametric position that substantially connects the protrusions 7, 10. Fold it onto the plate 1 using the portion 11 as a fulcrum (FIG. 5). Then,
Pass the wire 3' between the two rows of claws 15, 15',
Wrap the wire end around the protrusion 10 (FIG. 4).

In order to prevent the wire 3' from deviating from the groove 3, after removing the cross member 21, a hot tool having a plurality of trapezoidal conical portions 22, 22', 22'', ..., 22n is heated into the groove 3. It is also possible to press the wire 3' onto the surface of the plate 1 containing the wire 3' and press the edge of the groove 3.However, as shown in FIG. It can also be tilted in the direction.Thus,
The wire 3' placed under tension in the groove 3 is prevented from coming off. Furthermore, the width of both upper edges of the groove 3 is made smaller than the diameter of the wire 3', and the wire 3' is inserted into the groove 3.
It can also be sealed inside.

FIG. 7 shows the use of the apparatus according to the invention for making branch pipe connections in the main pipe 23 in the field. In this case, the branch part is composed of a saddle part 24 having a curvature equal to the outer diameter of the main pipe 23, a tubular chimney 25 provided thereon, and a branch pipe 26 led from the side of the saddle part 24. It is fixed on the tube 23.

A perforator 28 is adapted to be screwed into the internal thread 27 of the chimney 25, and the lower end 29 of this perforator 28 passes through an internal hole 30 of the chimney 25 to insert a pre-fused conduit as described below. It is possible to drill through 23 walls. After the above-mentioned penetration and after the wall of the conduit has solidified, the perforator 28 together with the sealing gasket 31 is pulled up above the branch pipe 26 and taken out.

To heat and melt the plastic material constituting the conduit 23 at the location where the branch pipe connection is required,
The apparatus according to the invention as described with reference to FIGS. 1 to 6 is used. The plate 1 loaded with the heating wire 3' is placed below the saddle 24, and the fasteners are applied to the positions of the two legs 32, 33 of the saddle 24 to tighten the saddle 24.
is crimped and held on the conduit 23. Then plate 1
terminals 7, 10 of are connected to a power source to melt or soften the corresponding portions of conduit 23. plate 1
Before the portion of the conduit 23 corresponding to
Remove from. A hole is thus formed and a seal is achieved by merging the plate 1 and the wall of the conduit 23 at least at the surface.

However, when molding the saddle 24 of the branch pipe connector, it is advantageous to incorporate into the saddle 24, as shown in FIG. 9, a heating plate 1 of the type described in FIGS. 1-6.

That is, the plate 1 is placed on the protrusion 34 of the mold, which is curved in accordance with the shape of the saddle 24 to be produced, with the slides 35 and 36 placed in the retracted position when the mold is opened. Next, the chimney 2 is equipped with an injection runner 39.
The upper die 37 having the protrusion 38 forming the cavity No. 5 is lowered to fix the center of the plate 1. Next, the slides 35 and 36 are closed to move to positions 35' and 35'.
36' and fold as shown in plate 1'. A thermoplastic material is injected into the thus closed mold to produce a branch pipe connector in which the plate 1' is embedded. At the same time, a small protective chimney 40, 40' is formed surrounding the terminals 7, 10 of the plate 1, and a wire 3, passing between the tabs 15, 15', is placed on the portion 13 of the tongue 12 bent over the plate. It is preferable to form a thick walled portion 41 to protect the pipe (Fig. 10). Figs. Ta. For the sake of simplicity, plate 1 is shown in Figure 11.
is omitted from the illustration, but is shown in FIG. 12.
Incidentally, FIG. 12 is a central longitudinal sectional view of FIG. 11.
In these figures, identical elements are designated by the same symbols as above.

A half ring made of plastic material is used as a fastener for tightening the saddle 24 in which the plate 1 according to the invention is embedded, in which the terminals 7, 10 are equipped with bare heating wires 3' protected by chimneys 40, 40'. 42 is used. The center portion of this half ring 42 is shaped to accommodate a cylinder, and its edges are provided with U-shaped grooves 43, 44 whose height decreases from one end to the other. In these grooves 43 and 44, the saddle 24
legs 32, 33 engage, thus the saddle 24 clamps the conduit 23 and the plate 1 tightens the said conduit 23.
It is crimped and welded well to the outside wall of the

In another embodiment, the U-shaped grooves are of the same height, but instead the legs 32, 33 are angled relative to the axis of the conduit.

Of course, the present invention is not limited to the above-described embodiments, and various design changes are possible.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of a structure according to the present invention, Fig. 2 is a plan view of the structure of Fig. 1 showing the surface including the helical groove, and Fig. 3 is a heating of the helical groove. FIG. 4 is a detailed view showing the connection terminal of the structure according to the present invention, and FIG. 5 is a plan view showing how the wire is installed, and FIG. a top view of a heating device obtained from a structure according to the present invention with a tool installed;
FIG. 6 is a partial vertical sectional view of a heating device obtained from a structure according to the invention, showing the special shape of the radial cross section of the groove; FIG. Drawings showing a branch part and a main pipe including a heating device, FIG. 8 is a cross-sectional view taken along the line - in FIG. 7, and FIG. 9 shows a heating device obtained from a structure according to the present invention in a saddle section. Schematic diagram of the injection mold for assembly,
FIG. 10 is a sectional view taken along the line - in FIG. 8 showing the exit of the heating wire, FIG. 11 is an exploded perspective view of the saddle and the tightening half ring, and FIG. 12 is a combination of both members. FIG. 12 is a cross-sectional view of FIG. 11 in a state shown in FIG. 1... Plate, 1'... Opening, 2... Surface of plate with groove, 3... Spiral groove, 3'
... Heating wire, 4 ... Winding, 7, 10 ... Protrusion, 12 ... Tongue piece.

Claims (1)

[Scope of Claims] 1. A plastic structure for use in a heating device for heating an element made of plastic material to create holes, which has a relatively thin thickness, has an opening 1' in the center, and has an opening 1' on one side. The plate 1 is provided with a helical groove 3 for accommodating the heating wire 3', and a first protrusion 7 is provided on the surface of the plate 1 where the groove is provided so that one end of the heating wire 3' can be accommodated. A plastic structure characterized in that it can be locked, and a similar second projection 10 is provided at a position distant from the first projection 7 so that the other end of the heating wire 3' can be locked. 2. The plate 1 is substantially circular and has two ears 6, 6' carrying projections 7, 10, the outer turn of the spiral groove 3 disengaging the plate in the vicinity of said first projection 7. The plate 1 is provided with a tongue piece 12 near the ear 6' that supports the second protrusion 10. When bent, at least a portion of the wire 3' assumes a radial position.
2. The device according to claim 1, wherein the device can be insulated and supported until it emerges from the inner winding 14 of the groove and is locked to the second protrusion 10. 3. A plastic structure used in a heating device for heating an element of plastic material to produce holes, which is relatively thin in thickness and has a central opening 1' and a heating wire 3' on one side 2. It consists of a plate 1 provided with a spiral groove 3 for accommodating the heating wire 3', and a first protrusion 7 is provided on the surface of the plate 1 where the groove is provided so that one end of the heating wire 3' can be locked. The heating wire 3' is installed in a plastic structure characterized in that a similar second projection 10 is provided at a position apart from the first projection 7 so that the other end of the heating wire 3' can be locked. In the method of using the heating device 1 constructed as shown in FIG. , during the heating of the wire 3', by engaging the stopper with the leg of the saddle 24, or by inserting the inclined locking groove 43,
By engaging a half ring comprising 44,
Alternatively, the method of use is characterized in that the saddle is firmly held on the conduit by a tightening action due to elastic deformation of the half ring and/or the saddle.