Pipe joints or couplings – Elbow
Reexamination Certificate
2000-09-27
2002-10-29
Nicholson, Eric K. (Department: 3679)
Pipe joints or couplings
Elbow
C285S423000, C285S183000, C285S903000
Reexamination Certificate
active
06471251
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an elbow which can be suitably connected mainly to the bent piping portions of pipe bodies, and a method for manufacturing the same elbow. Although the present invention does not relate directly to the sizes of the diameters of pipe bodies, the present invention particularly relates to an elbow which is suitably connected mainly to the bent piping portions of large-sized pipe bodies having a large inside diameter, for example 1,000 mm, 2,000 mm and so on.
Conventionally, in an elbow of the above type and a method for manufacturing the same, as shown in
FIGS. 11
to
16
, a synthetic resin pipe body P having a required length and including a spirally corrugated pipe wall
1
is cut and divided along a cut line C having a required inclination angle in the inclined direction thereof to thereby produce two pipe bodies, one of the thus cut and divided two pipe bodies is turned in the circumferential direction of the pipe body P with respect to the other to thereby change the relative angles of the cut surfaces of the pipe body, and the cut end faces of the two pipe bodies are butted against each other and are then connected together in a watertight manner. (For example, refer Japanese Patent Examined Publication No. Hei. 4-44157, especially, a structure shown in
FIG. 1
thereof).
Describing the above structure more concretely with reference to the accompanying drawings, to manufacture an elbow E having an angle of 45° shown in
FIG. 13
, as shown in
FIG. 11
, the middle portion of a blank material, that is, a spirally corrugated synthetic resin pipe body P, which has been cut to a required length, is cut and divided along a cut line C inclined at an angle of 22.5° with respect to an intersection line in the longitudinal direction thereof to thereby provide two pipe bodies p, p′. Next, of the thus divided two pipe bodies p, p′, one pipe body p′(in the case of
FIG. 12
, a pipe body shown on the right side thereof) is turned by an angle of 180° in the circumferential direction thereof to change the relative angles of the cut surfaces of the pipe bodies p, p′ in such a manner that the cut surfaces of the two divided pipe bodies p, p′ can have a V-like shape when it is viewed from the side surface side thereof; next, the respective cut end faces of the two pipe bodies p, p′ are butted against each other (FIG.
12
); the whole peripheries of the thus butted surfaces F are connected together by wire members w such as wires which are disposed at two or more portions of the butted surfaces F so as to extend across the two sides of the respective butted surfaces F; a sheet-shaped connecting material g formed of blank material, which has the same property as the material of the pipe body P and is highly fusion-weldable to the pipe body P material, is heated and melted and is then stuck onto the outer peripheries of the thus-connected butted surfaces F in several layers, thereby closing or sealing spaces formed on the spirally corrugated cut surfaces of the butted surfaces F over the whole peripheries of the pipe bodies; and, the inner surface sides of the pipe bodies are also sealed similarly to thereby connect together the two pipe bodies p, p′ in a watertight manner. That is, the elbow E is manufactured in this manner.
Now,
FIGS. 14
to
16
show means for manufacturing an elbow E having a bending angle of 90° shown in FIG.
16
. As shown in
FIG. 14
, a blank material, that is, a synthetic resin pipe body P is cut on the two sides of the middle portion of the pipe body P along cut lines C, C respectively inclined at an angle of 22.5° and at an angle of −22.5° with respect to an intersection line in the longitudinal direction of the pipe body P; with the thus obtained middle portion pipe body p′ left unchanged as it is, the two-side pipe bodies p, p are respectively turned by an angle of 180° in the circumferential direction thereof to thereby change the relative angles of their respective cut surfaces; next, the thus angle-changed cut surfaces are butted against each other (FIG.
15
); and, the respective butted surfaces F, F are connected together in a watertight manner using similar means to the above-mentioned case, thereby manufacturing the elbow E.
Also, in place of the above-mentioned sheet-shaped connecting material, there is also used means in which glass fiber sheets are stuck on the outer peripheries of the butted surfaces F, F in several layers using fused resin.
As described above, in the conventional spirally corrugated pipe elbow E of this type, there is employed the above means that spirally corrugated pipe body is cut at a required angle to two pipe bodies, one of the two divided pipe bodies is turned 180° with respect to the other to change the respective angles of the cut surfaces of the two pipe bodies, the cut surfaces of the two pipe bodies are then butted against each other, and the thus butted surfaces of the two pipe bodies are connected together in a watertight manner over the whole peripheries thereof. However, this means raises a problem that it requires great trouble and time as well as a skilled technique; and, this means also raises another problem that the mutually butted surfaces of the two pipe bodies, including large spaces produced between the butted surfaces due to the mutual deviations between the spirally corrugated portions of the two pipe bodies, must be positively closed over the entire peripheries thereof and thus must be connected together in a watertight manner. Also, in the conventional spirally corrugated pipe elbow E, there is found a further problem that, even in case where the elbow E is manufactured with the great time and trouble taken, the connected portions of the elbow E obtained over the whole periphery thereof can be damaged in part due to vibrations produced during delivery of the elbow E, or due to improper handling of the elbow E, or due to biased loads such as uneven ground pressures applied to the elbow E after it is embedded into the ground, which gives rise to easy leakage of water.
SUMMARY OF THE INVENTION
In view of the above, the present invention aims at reducing and solving the above-mentioned problems found in the conventional elbow and in the conventional method for manufacturing the same. Accordingly, it is an object of the invention to provide an elbow having a structure free from the above water leakage and a method capable of manufacturing such elbow easily and quickly.
In attaining the above object, according to a first aspect of the invention, there is provided a first structure for an elbow. Referring to the first structure using reference characters used in the below-mentioned preferred embodiments of the invention, after a bend forming portion of a pipe body P having a given length and including a spirally corrugated pipe wall
1
, with a partial portion a of the pipe wall
1
existing in the peripheral direction of the pipe body P left uncut, is cut and removed from the pipe body P in the form of a cut portion having a substantially V-like shape when it is viewed from the side surface side thereof, the thus obtained two cut surfaces are then bent and contacted with each other with the uncut pipe wall portion a set on the large diameter side, and the thus contacted portions t are connected together in a watertight manner using connecting material m.
Also, in the case of a second structure according to the invention, a bend forming portion of a pipe body P having a given length and including a spirally corrugated pipe wall
1
, with a partial portion a of the pipe wall
1
existing in the peripheral direction of the pipe body P left uncut, is cut and removed from the pipe body P in the form of a cut portion having a substantially V-like shape when it is viewed from the side surface side thereof, and the mutually opposing cut bottom portions (e), (e) of the V-shaped cut portion are cut and removed in such a manner that they are shifted substantially by one pitch width r of the spirally corrugate
Egoshi Kimihiro
Yoshida Tatsushi
McGinn & Gibb PLLC
Nicholson Eric K.
Totaku Industries, Inc.
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