Method for waterproofing junction of main and branch wires and cover therefor

Abstract: A method for waterproofing a junction of branch wires with the main by enclosing the junction in a plastic cover containing a putty sealant and filling the inside of the cover with the sealant and a cover therefor are disclosed, the method comprising providing projections ( n and m ) on the inner side of cover ( 1 ) by which parallel wires ( b ) enfolded in the cover are vertically shifted or the parallel wires are not only vertically shifted but laterally spread by the projections to make enough space between adjacent wires ( b ) for letting the putty sealant in.

Description: FIELD OF THE INVENTION This invention relates to a method for waterproofing a junction of branch wires with the main and to a cover which can be used for carrying out the method. BACKGROUND OF THE INVENTION It is known that waterproofing of a junction of low-voltage insulated wires is achieved by enfolding the wire junction in a cover containing therein a putty sealant, compressing the putty sealant between the upper and lower halves of the cover to spread the putty sealant within the cover. However, where branch wires paralleling the main are connected to the main, the paralleling wires are packed tight in the cover to form gorges that the putty sealant is difficult to enter, resulting in a failure of satisfactory waterproofing. In order to overcome the above disadvantage, it has been proposed to provide projections on the inner surfaces of the upper and lower halves of a cover so that the projections may wedge into the paralleling wires to spread the wires laterally (i.e., to the width direction of the cover) to form enough space for letting a putty sealant in (see Japanese utility Model Appln. No. 59-109075). According to this method, however, since the wires are laterally spread for making enough space, the cover should have all the more width, and so the wire junction should have all the greater dimension. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for waterproofing a junction of branch wires with the main (hereinafter simply referred to as a wire junction) by using a cover containing a putty sealant, in which complete waterproofing with the putty sealant can be achieved while minimizing the increase of the dimension of the junction. Another object of the present invention is to provide a cover which can be used in carrying out the above waterproofing method. The present invention relates to a method for waterproofing a wire junction comprising enfolding the junction in a cover while compressing a putty sealant in the cover to fill the inside of the cover with the sealant, in which the cover has provided on the inner side thereof projections so that parallel wires enfolded in the cover are vertically shifted or not only vertically shifted but laterally spread by the projections to leave enough space between adjacent wires for letting the putty sealant in. According to the present invention, space can be formed between adjacent parallel wires by vertical shift of the wires. As compared with space formation only by lateral spread of the parallel wires, there is no need to increase the width of the cover, and the junction thus has a reduced dimension. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a wire junction to be waterproofed by the present invention. FIG. 2(a) is a plane view of an embodiment of the cover for a wire junction according to the present invention. FIG. 2(b) is a cross section of the cover of FIG. 2(a) in its fastened state as enfolding a wire junction therein. FIG. 3(a) is a plane view of another embodiment of the cover for a wire junction according to the present invention. FIG. 3(b) is a cross section of the cover of FIG. 3(a) in its fastened state as enfolding a wire junction therein. FIG. 4(a) is a plane view of still another embodiment of the cover for a wire junction according to the present invention. FIG. 4(b) is a cross section of the cover of FIG. 4(a) in its fastened state as enfolding a wire junction therein. FIG. 4(c) is a side view of partitioning walls in the cover of FIG. 4(a) in its fastened state making a hole through which a single wire is led out from one end of a wire junction. FIG. 5(a) is a further embodiment of the cover for a wire junction according to the present invention. FIGs. 5(b) to (f) are each a cross section of the cover of FIG. 5(a) along b-b line, c-c line, d-d line, e-e line or f-f line, respectively. FIGs. 6(a) and (b) each illustrate the state of parallel wires enfolded in the cover of FIGs. 5. FIG. 7(a) is a still further embodiment of the cover for a wire junction according to the present invention. FIG. 7(b) is a cross section of the cover of FIG. 7(a) in its fastened state as enclosing a wire junction therein. FIG. 7(c) illustrates the view of one end cf the cover of FIG. 7(a) in its fastened state from which a single wire is led out. FIG. 8(a) is a perspective view of a modification of the cover for a wire junction shown in FIG. 7. FIG. 8(b) is a cross section of the modification shown in FIG. 8(a). FIG. 9(a) is a yet further embodiment of the cover for a wire junction according to the present invention. FIG. 9(b) illustrates the curving single wire at cne end of the cover of FIG. 9(a) in its fastened state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be illustrated by referring to the accompanying drawings. FIG. 1 shows a wire junction, an object of waterproofing according to the present invention. The wire junction to be waterproofed by the present invention preferably include those in which each wire has a relatively small diameter and more than one branch wires are connected to the main. The wire junction shown in FIG. 1 is comprised of main insulated wire a with its middle part bared and a plurality of branch insulated wires b connected to the bare main wire by means of fitment c . A single wire is on the right-hand side of fitment c , and parallel wires are on the left-hand side. FIG. 2(a) is a plane view of one embodiment of a plastic cover which can be used in the present invention in its developed state. 11 and 12 are each a complementary half of cover 1 joined via hinge 2 . At one end of cover 1 indicated by A from which a single wire is led out, there are provided partitioning walls 41 and 42 each having groove 40 into which a single wire is fit. On fastening two halves 11 and 12, these partitioning walls form a diaphragm for blocking a putty sealant while making a hole through which a single wire is led out as hereinafter described. Cover 1 has tapered tip 132 at end A so that the junction may not catch on other objects when the single wire is pulled at. At the other end of cover 1 , indicated by B , from which parallel wires are led out, there are provided projections n each of which is to wedge between parallel wires and projections m each of which is to thrust the parallel wires from the upside and the downside alternately. The height of projections m is less than that of projections n . Fastening projection 31 is provided on the side of one half of cover 1 , and catch therefor 32 is provided on the side of the other half. when a wire junction is enfolded in cover 1 , the parallel wires b are laterally spread by projections n while being vertically shifted as shown in FIG. 2(b). FIG. 3(a) illustrates a plane view of another embodiment of the plastic cover according to the present invention in its developed state. In this embodiment, projection n and m each have a right triangle cross section in such a manner that when cover 1 is folded into two and fastened, one side of projection n, indicated by n ' and that of adjacent projection m , indicated by m ', are tapered to reverse directions as shown in FIG.3(b). In this case, central wire b ₂ is pushed downward while wire b ₃ on the right-hand side is pushed upward thereby achieving vertical shifting of wires b ₂ and b ₃. Central wire b ₂ and left wire b ₁ are also relatively shifted in the vertical direction as a result of the downward shift of central wire b ₂. FIG. 4(a) is a plane view of a further embodiment of the plastic cover according to the present invention in its developed state. In this embodiment, the width of hinge 2 is set so that when cover 1 is folded and fastened, as shown in FIG. 4(b), tapering 21 on each side of hinge 2 may function as a projection against wire b ₃ contacting with the inner surface of hinge 2 . The width of hinge 2 is usually 1/4 the height of a fastened cover. Thus, the parallel wires are in contact with projections in different ways and, as a result, a shearing action in the vertical direction is exerted on the parallel wires thereby to shift the parallel wires up and down. Further, as shown in FIG. 4 (c), grooves 40 of partitioning walls 41 and 42 are designed so that they may form a vertically oblong hole in which a single wire is given free play in the vertical direction. As a result, the force imposed on parallel wires b ₁ to b ₃ by projections m is prevented from traveling from the single wire passing on the grooves 40 directly to the body of cover 1 . Deformation of the cover can therefor be avoided even if the wall thickness of cover 1 is reduced. FIG. 5(a) illustrates a still further embodiment of the plastic cover of the present invention. FIGs. 5(b), (c), (d), (e), and (f) are cross sections of cover 1 along b-b line, c-c line, d-d line, e-e line, and f-f line, respectively. In this embodiment, cover 1 in its fastened state has the both ends thereof tapered as shown by symbols 132 and 131 , and two pairs of fasteners 31 and 32 are provided. Projections n ₁and n ₂ are provided on the inner side of upper half 11, and projections m ₁ and m ₂ are on lower half 12 . Projection n ₁ of upper half 11 and projection m ₁ of lower half 12 are aligned on the same line along the width direction of cover 1 (the direction perpendicular to the parallel wires) at such positions that they may not face each other when the two halves are fastened. Similarly, projection n ₂ of upper half 11 and projection m ₂ of lower half 12 are on the same line which is parallel to the line of projections n ₁ and m ₁ at such positions that they may not face each other when the two halves are fastened. None of these projections are on the same line in the longitudinal direction of cover 1 in its fastened state. That is, none of them are at the same position in the width direction of cover 1 . On one end of cover 1 from which a single wire is led out is provided partitioning wall 4 , and groove 40 of the wall is for receiving a single wire. The position of partitioning wall 41 provided on upper half 11 and that of partitioning wall 42 on lower half 12 are slightly shifted from each other in the longitudinal direction so that, when cover 1 is folded and fastened, walls 41 and 42 overlap to form a diagram while making a hole through which a single wire passes. S is a putty sealant. FIGs. 6(a) and (b) each show the usage of the cover of FIG. 5 with a wire junction being enfolded therein. In the case of FIG. 6(a), the wires pushed by the projections on the upper half of the cover bend down whereas the wires pushed by the projections on the lower half of the cover bend upward. Since the position of contact with the projection differs among the wires, the shape cf the bend differs among the parallel wires thereby to form space between each two adjacent wires. In the case of FIG. 6(b), projections n ₁ and m ₁ on the same line wedge between the parallel wires to makes wires b and b ' tight, but at the same time, projection m ₂ on the other line wedges between wires b and b ' to spread them laterally. Accordingly, sufficient space can be formed between parallel wires b and b '. Waterproofing of a wire junction according to the present Invention is achieved by adhering putty sealant S , e.g., a sealing compound mainly comprising unvulcanized rubber, to the middle part of the inner side of the cover in its developed state as shown, for example, in FIGs. 5(a) and 5(c), and folding the cover with a wire junction being interposed therebetween. Upon being enfolded in the cover, the parallel wires are not only spread laterally but vertically shifted by the projections provided on the inner side of the cover to leave sufficient space among themselves. The thickness (e) of the putty sealant on a cover in its developed state is more than a half the thickness (d) of the cover in its folded and fastened state, i.e., d/2<e, so that the putty sealant is compressed on folding the cover. The compressed sealant flows toward the projections, and the open space among the parallel wires is thus filled with the sealant. On the other hand, the flow of the sealant toward the opposite end, i.e., the outlet for a single wire, is blocked by the diaphragm of partitioning walls, and the diaphragm serves as a back-pressure plate to ensure the flow of the sealant toward the parallel wires and to accelerate sufficient filling of the space with the sealant. If desired, a diaphragm may be provided at the end of the cover frcm which parallel wires are led out so that overflow of the putty sealant from that end may be prevented while increasing the inner pressure of the sealant thereby filling the space among the parallel wires with the sealant with higher reliability. For example, as shown in FIGs. 7(a) ) and 7(b), projections 5 functioning as the above-mentioned diaphragm are provided at the positions corresponding to the space formed by projections n and m . The covers shown in FIGs. 3 to 6 may also be provided with such projections functioning as diaphragms as in FIGs. 7(a) and (b). While the end portion of the cover of FIG. 7, indicated by A , formed by upper and lower halves 11 and 12 , from which a single wire is led out, is tapered on both sides thereof, end portion A may be tapered on only one side thereof as in the cover shown in FIG. 2(a). In the cover of FIG. 7, tips 111 and 112 of upper half 11 and lower half 12 engage with each other so as to provide a double wall structure as shown in FIG. 7(c). By providing the double wall structure formed by the tips 111 and 112 , a mechanical strength of the cover is increased and it is possible to prevent the sealant in the cover from leaking surely. 411 in FIG. 7(a) is a partitioning wall having groove 412 for receiving a single wire. In addition, the end portion of the cover of FIG. 7, indicated by A , formed by upper and lower halves 11 and 12 , from which a single wire is led out, is tapered, so that a handling ability of the pulling operation can be improved and a space for mounting the cover can be decreased. Further, as shown in FIG. 8(a) and FIG. 8(b), an inner wall of the tip 112 , which is closer to the hinge 2 , may be provided with a cutout portion 121a at the higher corner thereof in such a manner that a closing/assembling operation between the upper and lower halves 11 and 12 is not interrupted by contacting the higher corner of the inner wall of the tip 112 with an inner wall of the tip 111 . By providing the cutout portion 121a, it is possible to conduct the closing/assembling operation between the upper and lower halves 11 and 12 via the hinge 2 smoothly. According to the above-described waterproofing method, the cover undergoes deformation under an elastic stress due to the resistance of the compressed putty sealant on being folded and fastened. The cover is restored to its original shape with time while maintaining the equilibrium between the stress of the cover and the stress of the putty sealant. Finally, the flow front of the putty sealant reaches the both ends of the cover (or diaphragms), and the stress of the cover becomes almost zero. Filling of the sealant into the space among the parallel wires has been completed before the above state is reached. In order to ensure complete filling, it is effective to sufficiently increase the initial compression ratio of the putty sealant. The initial compression ratio of the sealant depends on not only the ratio of the total thickness of the sealant applied to the upper and lower halves of the cover (2e) to the thickness (d) of the cover in its folded and fastened state, i.e., 2e/d (>1), but also the volume of the wire junction. However, in cases of using wires having a small diameter, the compression ratio of the sealant is substantially decided by the ratio 2e/d. In these cases, the ratio 2e/d is preferably 2 or more. In carrying out waterproofing of a wire junction according to the present invention, a putty sealant in the form of a sheet may previously be wound around the junction, on which the cover of the present invention is then put and fastened. In this case, too, even if the volume of the wire junction is small, the compression ratio of the sealant can be increased sufficiently by increasing the volume of the sealant applied. According to the foregoing preferred embodiments, even if the cover is moved in its longitudinal direction, the wires are prevented from coming off the cover because either of the projection and the diagram (partitioning wall) catches on fitment c . In particular, where a plurality of projections 6 are provided at the end from which a single wire is led out on upper half 11 and lower half 12 alternately at some intervals in the longitudinal direction as shown in FIG. 9(a), single wire a is vertically thrust by projections 6 on being enfolded and is curved as shown in FIG. 9(b). Thus, cover 1 is fixed to single wire a firmly to ensure prevention of the wire junction from coming off cover 1 . The above-mentioned projections for curving a single wire at the end of a cover may also be provided in all the other embodiments shown in FIGs. 3 to 7. While the end portion of cover 1 shown in FIG. 9 from which a single wire is led out is tapered from both sides thereof similarly to the cover of FIG. 7, the end portion may of course be tapered from only one side thereof as in the cover of FIG. 2(a). While according to the above-described embodiments all the branch wires are led out from only one end of the cover, it is possible to lead cut branch wires from both ends of the cover. In this case, the partitioning walls or projections for curving a single wire should be replaced with projections for laterally spreading parallel wires and those for vertically shifting parallel wires within the cover as provided at the other end. Further, while the upper and lower halves of the covers according to the foregoing embodiments are integrally molded with hinge 2 therebetween, it is possible to separately prepare the two halves each having fasteners on both sides thereof, and the two halves are fastened with a wire junction being interposed therebetween. According to the present invention, even if a plurality of branch wires are connected to the main, enough space can be surely fcrmed among parallel wires within the cover for letting a sealant flow in thereby to accomplish watertight waterproofing. Moreover, since the parallel wires are vertically shifted in the cover, the degree of lateral spreading of wires can be minimized so that the necessary width of the cover may be minimized, i.e., the size of the wire junction is reduced. While the invention has been described in detail and with reference to specific examples thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the scope of the claims.

Claims: A method for waterproofing a junction of branch wires with the main comprising enfolding the junction in a cover while compressing a putty sealant in the cover to fill the inside of the cover with the sealant, in which projections are provided on the inner side of said cover in such a manner that parallel wires enfolded in the cover are vertically shifted by said projections to leave enough space between adjacent wires for letting said putty sealant in. A method for waterproofing a junction of branch wires with the main according to claim 1, in which said projections are provided in such a manner that parallel wires enfolded in the cover are vertically shifted and also laterally spread by said projections. A method for waterproofing a junction of branch wires with the main according to Claim 2, wherein said lateral spreading and vertical shifting of the parallel wires are effected by utilizing the inner surface of a hinge of the cover as well as said projections provided on the inner side of the cover. A cover for waterproofing a junction of branch wires with the main in which the junction is enfolded in a cover while compressing a putty sealant in the cover to fill the inside of the cover with the sealant, comprising: projections provided on the inner side of said cover in such a manner that parallel wires enfolded in the cover are vertically shifted by said projections to leave enough space between adjacent wires for letting said putty sealant in. A cover according to claim 4, in which said projections are provided in such a manner that parallel wires enfolded in the cover are vertically shifted and also laterally spread by said projections. A cover according to claim 5, in which said projection are provided on the inner side of said cover for laterally spreading parallel wires enfolded therein and projections for vertically shifting said parallel wires at prescribed intervals in the width direction of the cover. A cover according to claim 6, in which each of said projections having at least one side thereof tapered with the direction of the tapering of one projection being opposite to that of the adjacent projection. A cover according to claim 4, in which a hinge is provided with a hinge of said cover in such a manner that said lateral spreading and vertical shifting of the parallel wires are effected by utilizing the inner surface of said hinge as well as said projections provided on the inner side of the cover. A cover according to claim 4, in which said projections are provided on the upper and lower halves of the cover at positions shifted in the width direction of the cover. A cover according to claim 4, in which said projections are aligned in a plurality cf lines perpendicular to the longitudinal direction of the cover at prescribed line intervals, with the positions of all the projections being different in the width direction of the cover. A cover according to any one of claims 4, in which a projection functioning as a diaphragm for blocking said putty sealant from overflowing to the end of the cover opposite to the direction toward the space formed among the parallel wires. A cover according to claim 4, wherein said cover is for a wire junction comprising a single wire on one end thereof and a plurality of parallel wires on the other end thereof, and a plurality of projections for curving said single wire are provided on the inner side of the cover.

Inventors: HIROSHIMA KATSUMI C O NITTO DE, KINOSHITA MICHITAKA C O YAZAKI, OHASHI YUKIO C O YAZAKI PARTS, TAHARA MASAHARU C O NITTO DENK, HIROSHIMA, KATSUMI, C/O NITTO DENKI CORPORATION, KINOSHITA, MICHITAKA, C/O YAZAKI PARTS CO., LTD., OHASHI, YUKIO, C/O YAZAKI PARTS CO., LTD., TAHARA, MASAHARU, C/O NITTO DENKI CORPORATION
Applicants: NITTO DENKO CORP, YAZAKI CORP, NITTO DENKO CORPORATION, YAZAKI CORPORATION
Application year: 1993
Main classification: H02G15
IPC codes: H01R4, H02G15, H01R43