Patent ID: 9259127
Filing Date: 2016-02-16
CPC Classification: A47L,B29C,B29L,F16L

Claim Text:
1. A central vacuum cleaning pipeline comprising a pipe coupling piece and at least one pipe, said pipe comprises an inner and an outer surface, said pipe coupling piece comprises at least a first and a second opening defined by an envelope wall, said envelope wall comprises an inner and an outer surface, at least one of said first and second openings comprises an attachment section having an annular seal member arranged in said attachment section, said attachment section further comprises: a stop surface defined by a first annular recess extending around the periphery of said inner surface of said pipe coupling piece, said first annular recess extends a first distance from said first opening into said pipe coupling piece, said stop surface is configured to prevent said pipe from insertion greater than a predetermined distance along an insertion and retraction direction, and said first annular recess comprises a depth to align said inner surface of said pipe coupling piece with said inner surface of said pipe after assembly, so as to provide a smooth transition between said pipe coupling piece and said pipe; the at least one of said first and second openings is arranged to receive said pipe introduced into said at least one of said first and second openings along the insertion and retraction direction, so that said pipe coupling piece overlaps said pipe with a part of said inner surface of said pipe coupling piece at said attachment section, so that said annular seal member is arranged to seal between said inner surface of said pipe coupling piece and said outer surface of said pipe after assembly; wherein said pipe coupling piece comprises at least one hole through said envelope wall of said pipe coupling piece, extending in a radial direction from said outer surface of said envelope wall directly to said inner surface of said envelope wall; wherein said first annular recess comprises a second annular recess, the annular seal member being arranged in said second annular recess; wherein the hole exits in said second annular recess, said second annular recess having an extension corresponding to an extension of said annular seal member wherein said annular seal member overlaps said at least one hole in a longitudinal direction of the pipe coupling piece; and wherein said second annular recess is arranged between said first opening of said pipe coupling piece and said stop surface of said attachment section, so that an annular flange is provided between said second annular recess and said first opening.