JPH04502129A - Heat recovery article with strain relief - 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] Heat recovery article with strain relief The present invention is constructed from high modulus polymeric materials and has inherent strain relief means. Method for providing strain relief to heat recoverable articles made from high modulus polymer materials and a method of using the article to protect a transition section of a wire harness.

Heat-recoverable articles can be used for various purposes such as cable connections, pipelines, and wire harnesses. used to protect base materials. Such heat recoverable articles include tubes, Includes boots, transitions, covers, tapes, etc. such heat recovery The elastic articles are typically made from thermoplastic and/or elastomeric materials. Ru.

Certain applications of heat-shrinkable articles, such as wire and For applications such as cable harnesses and cable harnesses, the article may be exposed to temperatures of approximately 150-200°C. fuels, anti-icing solvents, working fluids, and decontamination even at such temperatures. Must be made from materials that are resistant to chemicals such as solvent removers. be. Such materials include, for example, vinylidene fluoride homo and copolymers. Kaina, commercially available from Marker, for example Benwald (Pennwald) (Kynar), ethylene/tetrafluoroethylene copolymers, e.g. Tefzel, commercially available from Dupont, Polya Included are rielene keterketone and other high performance polymers. however , these materials tend to be relatively stiff and have a large secant modulus. Ru. Heat-recoverable articles made from such materials, such as boots, transitions , rTJ type, rYJ type, etc., especially when wearing the harness. the exit foot portion of the article and/or the adjacent It is easy to break at the part where the connecting wire needs to be bent. This crack is located at the end of the exit leg. and/or as a result of excessive strain in the crotch portion of the article. One of this kind A common article is a transition as shown in Figure 1, where a wire - the bundle 10 enters the transition 1 through the first elongate outlet 2 and enters the two smaller Wire bundles 12 and 14 exit through outlet foot sections 3 and 4, respectively.

If we provide an intermediate convoluted region in at least one of the exit foot portions, such We have discovered that it is possible to uniquely provide strain relief to objects that are

The use of convoluted heat-recoverable tubing to provide flexibility is useful in this field of technology. It is known as For example, British Published Patent Application No. 2゜125.237 describes a flexible circuit European Published Patent Application No. 68.781 describes a spiral tube as a cable brake. Enough that one tubular outlet section of the pullout can be bent away from the pond. A cable breakout article is disclosed that has convolutions that provide flexibility. Chu To achieve sufficient flexibility of the tube-shaped outlet, the outlet has a relatively small modulus. material, such as low-density polyethylene with a 2% secant modicilas of approximately 20,000 It has been found that it is necessary to create a The above UK patent application is relatively rigid. No mention is made of the problem of strain relief in heat-recoverable articles made of polymeric materials.

One aspect of the invention is that the 2% linear modulus is at least about 30,000 psi. comprising a heat-recoverable hollow article made of a polymeric material, the article comprising at least having three integral elongated outlet elements, each having an end region of substantially uniform cross-section; at least one of the elements rotates during recovery of the article about the substrate. has an intermediate convoluted region that remains in the shape, and the convoluted region absorbs the strain inherent in the recovering article provide an escape.

Another aspect of the invention is to have a 2% linear modulus of at least about 30,000 psi. Method of providing inherent strain relief in hollow heat recoverable articles made from polymeric materials comprising at least three integral elongated outlet elements, the article comprising: each has an end region of substantially uniform cross-section, and the method includes: The method includes providing an intermediate convoluted region that remains convoluted during recovery of the article. It consists of

Another aspect of the invention is a 2% secant modulus of at least 30,000 psi. an intermediate convolution made from a polymeric material with a shape that remains convoluted upon recovery of the article; a heat recoverable tubular article having a convoluted region, the convoluted region being recoverable; Provides strain relief inherent to the article.

Yet another aspect of the invention is that the 2% secant mode of at least 3j) 000 psi A method of providing inherent strain relief to a heat-recoverable tubular article having diteras and the method provides the article with an intermediate convoluted region that remains convoluted upon recovery of the article. It consists of

FIG. 1 shows a typical prior art transition of a wiring harness.

FIG. 2 is a cross-sectional view of the transition of the present invention.

FIG. 3 shows a heat recoverable tubular article 30 of the present invention. The article has two end areas 31 and 32 and an intermediate convoluted region 33.

Articles of the invention are heat recoverable.

A heat recoverable article is an article whose dimensional structure can be substantially changed when subjected to heat treatment. It is.

Typically, when heated, these articles change from the front side −〇 deformed shape toward the original shape. As used herein, the term "heat recoverable" refers to It also includes articles that take on a new structure when heated, even if they are not deformed.

In its most common form, such articles are described, for example, in U.S. Pat. No. 2, No. 3,086,242 and No. 3,957,372. As such, it is made from a bottom material that exhibits elastic or plastic memory properties. for example, As revealed in U.S. Patent No. 2,027,962, A stable form can be achieved by, for example, extruding a tube into a dimensionally thermostable form while still hot. It may be a temporary form of a continuous process of expansion, and in other cases, a A prepared dimensionally heat-stable article is transformed into a dimensionally heat-stable form in a separate process. Ru.

One method of making heat recoverable articles is to bring the vol/mer material into the desired heat stable form. Molding and then cross-linking the polymer material to the crystalline melting point of the polymer or the amorphous material In this case, heat the article until it becomes soft, deform the article, and maintain the deformed state of the article. cooling the article in such a deformed state. When using the item, Since the deformed deafness is thermally unstable, upon heating the article assumes its original thermally stable shape.

Articles of the invention have a pressure of at least about 30,000 psi, preferably at least about 500 psi. 00 psi, most preferably at least about 75,000 psi. Made from a polymeric material with The 2% linear modulus is generally about 200 000 psi or less, preferably about 120,000 psi or less. polymer material from about 50,000 psi to about 200,000 psi, preferably about 70,000 psi It is preferred to have a 2% linear modulus in the range of i to about 150,000 psi.

Preferred materials include vinylitine fluoride polymers, ethylene-tetrafluoride polymers, Included are polyethylene copolymers, (boriyal ether ketones), and the like. Special Preferred materials are vinylidenofluoride and fluoropropylene. It is a thermoplastic copolymer.

The wall thickness of the recovered article is about 10 to about 200 mils, preferably about 2 Must range from 0 to about 150 mils, most preferably from about 40 mils to about 100 mils. There is. In general, the strain relief of the present invention applies to relatively large modules with relatively large wall thicknesses. Articles of modulus or made from materials of very large modulus regardless of wall thickness It is most advantageous for products that are Relatively small modulus with relatively thick walls Articles made from materials and relatively large mods with very thin walls previously described A heat recoverable device having three or more elongate exit elements or foot portions, such as If the article is made from a high modulus polymeric material and is subjected to strain, e.g. When used in an ear harness and adapted to the path, it is easy to break. present invention In this case, an intermediate convoluted region is provided in the article to provide strain relief. The convoluted region is at least It also has one convolution and is generally formed as an integral part of the article. convoluted region The regions can be incorporated during molding or extrusion of the article.

FIG. 2 shows the three-legged transition of the present invention. In Figure 2, the transition 20 consists of elongated outlet elements 21, 22 and 23. Each leg has a substantial are provided with end regions 24, 25 and 27 of uniform cross-section, if necessary Provides a seal to the eel substrate. In the embodiment shown in FIG. 2, two exit foot portions 22 and and 23 are provided with intermediate convolution regions 27 and 28, respectively. Rotation avoids distortion and transmit strain from the end of the foot or crotch area depending on the area where the strain is applied, Distribute the strain over the convoluted region so that it is not concentrated at one point. This results in Cracks in the article at the ends 25 and 26 of the crotch region 29 or foot portions 22 and 23 transitions or adjacent The contact wire can be bent as desired. Number of convolutions to be supplied and their dimensions The method provides the desired degree of strain relief for the article depending on the article's modulus and end use. It can be designed to give If necessary, the wall thickness of the crotch region 28 may be greater than the wall thickness of the foot region. It can be designed to be large. This further reduces the possibility of cracking in the crotch area. .

FIG. 3 shows a heat recoverable tubular article 30 of the present invention. This item has two parts regions 31 and 32 and an intermediate convoluted region 33. During recovery, convoluted area provides strain relief so that the substrate on which the article recovers bends in the area adjacent to the article. This prevents cracking in the edge areas when the edges are broken.

Although the present invention has been described with reference to a three-legged transition, the present invention It is advantageous for heat recoverable articles having any number of elongate foot portions to provide That will be understood. Such items include boots (two exit feet), try Punto (four exit legs), T-shaped (three exit legs), etc. are included. It will be done.

international search report international search report US 8902883 S^　29920

Claims (1)

[Claims] Constructed from a polymeric material having a 1.2% secant modulus of at least about 30,000 psi. a heat-recoverable hollow article having at least three integral elongate exit elements; , each of the elements has an end region of substantially uniform cross-section, and at least one of the elements has an end region of substantially uniform cross-section. one remains convoluted upon recovery of the article around the substrate; an intermediate convoluted region having a convolution, the convoluted region having strain relief inherent in the recovery article; Goods to give. 2. The polymeric material has a pressure of at least about 50,000 psi, preferably at least The article of claim 1 having a 2% secant modulus of 75,000 psi. 3. The polymeric material has a pressure of about 50,000 to 200,000 psi, preferably about 75 Claim 1 having a 2% secant modulus of 000 to 120000 psi. Articles listed. 4. The wall thickness of the at least one element is from 10 mils to about 200 mils upon recovery. Article according to claim 1. 5. 2. The method of claim 1, wherein at least two of the elements have an intermediate convoluted region. Goods. 6. The claim 1 having three elongated outlet elements, two of which have intermediate convoluted regions. Articles described in scope 1. 7. a crotch region between the two elements, the crotch region being greater than the wall thickness of the end region of the element; 7. Article according to claim 6, having a large wall thickness. 8. Claim 1, wherein the polymeric material is vinylidene fluoride polymer. Items listed. 9. The article according to claim 1 is placed in the transition part, and then the article is added. Preservation of transition sections of wire harnesses comprising heating and recuperation protection method. 10. Polymeric material having a 2% secant modulus of at least about 30,000 psi A method of providing inherent strain relief to a hollow heat recoverable article made from a material, the method comprising: has at least three integral elongated outlet elements, each of which has a substantially uniform elongated outlet element. having an end region of cross-section, at least one of the elements having a convoluted shape upon recovery of the article; a method comprising providing an intermediate convoluted region that is up to. 11. Polymeric material having a 2% secant modulus of at least 30,000 psi having at least one convolution that remains convoluted upon recovery of the article A heat recoverable tubular article having an intermediate convoluted region, the convoluted region being An article that provides a unique strain relief to the article. 12. A thermally recoverable tube having a 2% secant modulus of at least 30,000 psi. A method of imparting strain relief specific to a convoluted article, which allows the article to remain convoluted during recovery. providing the article with an intermediate convoluted region of .