JPS6117645B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of forming a unit consisting of a flexible, threaded wire conduit and a termination member of thermoplastic material.

Cables which are widely used in driving parking brakes and clutches and which have other applications in industrial, marine and aircraft sectors, typically have a core that can move back and forth axially within a conduit. The conduit is formed from thread-wound wire, and the thread-wound wire forms several concentric outer layers. If such a conduit is cut in the middle, the wire will become unraveled at the cut point. This in itself is undesirable and requires that the conduit be provided with a termination member. In that case, there is a problem in that the frayed wire must be forced into the end piece. The present invention was born against this problem.

The object of the present invention is to provide a conduit formed from a threaded wire, or a conduit formed from two or more layers, the outer layer of which is formed from a threaded wire, and a periphery of the end of the conduit. and a terminal member fixed to and holding a threaded wire wound between the ends,
holding the conduit extension with the portion to be the end in a mold, injecting a thermoplastic material into the mold to form the termination member, and after the thermoplastic material has hardened, the conduit extension being in one piece; It is an object of the present invention to provide a method characterized in that the conduit is cut to separate it from the extension.

Thus, the wire portion of the unit according to the invention is held in place solely by the end piece without the use of extra means.

Although a single termination member may be formed in a molding operation, two termination members may be formed simultaneously in a single molding operation and the two separated by a cut that separates the conduit from its extension. good. The extension comes to include the termination member of another unit.

The outermost spirally wound wire provides widely spaced spirals above the closely spaced spiral layer, and the termination member holds the two spirals in place relative to each other. play a role. Through the molding process, thermoplastic material is forced to fill the spaces between adjacent convolutions, providing a seal between them.

The end member is long enough and flexible enough to disperse vibration and bending stress, and is designed so that when it is engaged with a mating member, the stress is not concentrated at the point of engagement. .

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The unit illustrated in FIGS. 1A and 1B includes a flexible conduit of threaded wire, indicated generically with the reference numeral 10, and at the end of the conduit 10, It includes a molded plastic cylindrical end member 11. The conduit 10 has an inner core 12 made of a flat wire wound in a threaded manner, an intermediate layer 13 made of an adjacent threaded wire with a relatively long pitch, and An outer layer 14 is wound in a threaded manner to hold the wire of the intermediate layer 13 in place. Conduit 10 is used as a sleeve through which internal elements are moved to transmit tensile-compressive forces to a location remote from the operator. The conduits and internal elements illustrated here constitute a cable such as that commonly used in parking brake and clutch drives.

The molded plastic termination member 11 has a cylindrical outer surface and an inner surface closely bonded to the exposed surface of the conduit 10 lying between the ends of the termination member 11. The plastic not only encases the widely spaced threaded outer layer 14 to hold it in place, but also penetrates into the gaps between adjacent windings in the intermediate helical wire 13. This is the horizontal line 1
3 in place while at the same time reliably preventing the passage of water or other corrosive fluids between the ends of each winding. Conduit 10 may be constructed from galvanized copper wire, and member 11 is molded from a flexible thermoplastic material such as nylon, acetal or polyethylene.

The length of the terminal member 11 is at least twice its diameter,
and is adapted to extend approximately 6.4 mm beyond the end of the engagement portion into which it is inserted and acts as a junction for the conduit. This length distributes vibrational stresses along the portion of the conduit covered by the termination member, thereby preventing stress concentration at the exit end of the member.

The above unit is mold 2 shown in Figure 2.
It is formed using 0. In this molding process,
A pair of cylindrical plastic termination members are molded simultaneously, one at the first conduit end and one at the adjacent end of the second conduit which initially forms an integral extension of the first conduit. The mold 20 has a cylindrical cavity 2
It consists of two mating halves 21 and 22 defining 3A, 23B and 23C.
The termination member at the end of one conduit is the cavity 23A.
A termination member on a separate conduit is formed within a portion of cavity 23B and a cut is made through portion 23B to separate the termination members from each other. be exposed. The ends 24 and 25 of the mold are open to allow two integral conduits to extend through the mold, and when the conduits are in place the ends of the cavity are closed by a sealing collar 27. It will be closed at. One of the halves 21 is provided with an opening 28 through which liquid thermoplastic material is injected into the cavity. Suitable materials include nylon copolymers, which are molded at temperatures of 238-260° C. and under maximum pressures of about 15 kg/cm ² . The injection time for such materials is about 3 seconds and the cycle time is about 10 seconds.

In using the mold 20, the halves 21 and 22 are first separated, ie the two uncut conduits are placed in position, and the sealing collar 27 is placed over the ends of the mold. The conduit is then closed around the conduit with a resilient end member that simultaneously seals the end and centers the conduit end. A prior art injection head (not shown) is inserted into the opening 28 and the liquid plastic fills the cavities 23A, 23B and 23.
C and is in intimate contact with the exposed surfaces of outer layer 14 and intermediate layer 13 and the surfaces of cylindrical cavities 23A, 23B and 23C. After the plastic has cooled and solidified from the fluid state, the two halves of the mold are separated and the conduit, which is still integrally connected to each other, is removed along with the molded part formed around it. then cutting the conduits at the molded portion to separate them from each other;
The result is two units of conduits with termination members fixed around their respective ends.

FIG. 3 shows an example of a semi-finished product immediately after the molding operation, which shows the conduits 1 which are still integrally connected to each other.
Structure 30 is shown molded around the edge of 0. The structure 30 as a semi-finished product is a mold 20
cylindrical portions 31A, 31B, and 31C corresponding to cavities 23A, 23B, and 23C. As shown in FIG. 1, this structure is cut using a ring cutter or the like with a constricted portion 31B having a small diameter, leaving two conduit ends terminated with termination members 11A and 11C. It is divided into two parts. Since the cutting operation is carried out on a small diameter section, the disturbances caused by the cutting are extremely small.

Note that throughout this molding operation, the two conduits remain connected together such that one forms an integral extension of the other. That is, during this operation, each serves to hold the other strands in their predetermined relative positions. The conduits are severed from each other after the mold cures and holds the spirals together in place. In the above embodiment, each termination member acts to hold in place not only the windings of the outer layer 14 but also the windings of the next inner layer 13.

In a typical application for a unit constructed as above, the end member is placed into a fitting such as a screwdriver or bushing that engages on the end member. This tightening operation presses the elastic plastic material into close contact with the wire of the intermediate layer 13, thereby making the sealing action even more reliable against fluids.

[Brief explanation of the drawing]

Figure 1A is a side view of a unit consisting of a conduit and a termination member secured around the end of the conduit, Figure 1B is an end view of Figure 1A, and Figure 2 is a molded unit in which the termination member is formed. A schematic diagram of the shaft section of the mold, and FIG. 3 is a side view of a semi-finished product produced by the mold illustrated in FIG. 2. In the diagram, the relationship between the main components and reference numbers is as follows. That's right. DESCRIPTION OF SYMBOLS 10... Generic conduit, 11... End member, 12... Core, 13... Spiral wire (intermediate layer), 1
4... line (outer layer), 20... generically indicated mold,
21, 22...Mold half body, 27...Sealing collar, 30...Semi-finished product.

Claims (1)

[Scope of Claims] 1. A conduit formed from a wire wound in a threaded manner, or a conduit formed from a wire having two or more layers, the outer layer of which is wound in a spiral manner, and an end of the conduit. A method of forming a unit consisting of an end member fixed around a part and holding a wire wound in a spiral manner between the ends, in which the part to be the end part is retaining an extension of the conduit in a mold, injecting a thermoplastic material into the mold to form the termination member, and separating the conduit from the integral extension after the thermoplastic material has hardened; A method characterized by cutting as much as possible. 2. The method of claim 1, wherein an integral extension of the termination member is formed that surrounds the integral extension of the conduit and is separated from the conduit and its integral extension simultaneously with the formation of the termination member. A method characterized in that the cutting operation separates the end member from its integral extension. 3. A method as claimed in claim 2, wherein the integral extension with the termination member forms a separate termination member, and the integral extension of the conduit forms a separate unit with the further termination member. A method comprising forming a separate conduit. 4. A method according to claim 2 or 3, characterized in that on each side of the cut, the thermoplastic material has a smaller diameter than the main part of its length. 5. A method according to any of claims 1 to 4, wherein the wire forms an outer layer, the turns of the outer layer are widely spaced, and the layer on which the outer layer is wound is closely spaced. Formed from wound wire,
and each of said termination members holds said layers of threaded wire in place between the ends of said termination members. 6. A method according to any one of claims 1 to 5, wherein each of the end members has a maximum diameter that is less than half its length.