Thread adaptor

Claim 2

Structure for providing a threaded connection on an annular wall formed of a soft material, comprising an annular element having radially inner and outer surfaces, said element being formed of a material substantially harder than said wall material, a radially projecting rib formed on one of said surfaces having a tapered axially inner first end, an opposite axially outer second end defining a radial shoulder, and a constant cross section mid-portion between said ends, and a coaxial thread formed in the other of said surfaces, said one surface being adapted to fit in facial engagement with said annular wall with said element locked to the annular wall by the radial shoulder extending into the annular wall against axially outward withdrawal from the annular wall.

Claim 3

The connection structure of claim 1 wherein said rib is disposed radially of said thread.

Claim 4

The connection structure of claim 1 wherein said rib is disposed substantially midway between the opposite ends of said thread.

Claim 5

The connection structure of claim 1 wherein said rib is formed on said radially inner surface of the annular elEment and said inner surface is adapted to fit about said annular wall.

Claim 6

The connection structure of claim 1 wherein additional ribs are provided on said one surface spaced circumferentially coaxially from said first said rib.

Claim 7

The connection structure of claim 1 wherein said annular element comprises an injection molded sleeve.

Claim 8

The connection structure of claim 1 wherein said rib has an axial length substantially one-third the axial length of said thread.

Claim 9

The connection structure of claim 1 wherein said annular element one surface has a diameter preselected to have an interference fit with said annular wall.

Claim 10

Structure for providing a threaded connection on an annular wall formed of a soft plastic material, comprising an annular element having radially inner and outer surfaces, said element being formed of a plastic material substantially harder than said wall plastic material, a plurality of radially inwardly projecting ribs formed on said radially inner surface each having a tapered axially inner first end, an opposite axially outer second end defining a radial shoulder, and a constant cross section mid-portion between said ends, and a coaxial thread formed in said radially outer surface, said radially inner surface being adapted to fit in facial engagement with said annular wall with said element locked to the annular wall by the radial shoulder extending into the annular wall against axially outward withdrawal from the annular wall.

Claim 11

Structure for providing a threaded connection on an annular wall formed of a soft plastic material, comprising an annular element having radially inner and outer surfaces, said element being formed of a plastic material substantially harder than said wall plastic material, a plurality of radially inwardly projecting ribs formed on said radially inner surface each having a tapered axially inner first end, an opposite axially outer second end defining a radial shoulder, and a constant cross section mid-portion between said ends, and a coaxial thread formed in said radially outer surface, said radially inner surface being adapted to fit in facial engagement with said annular wall with said element locked to the annular wall by the radial shoulder extending into the annular wall against axially outward withdrawal from the annular wall.

Claim 12

The connection structure of claim 9 wherein said inner surface has a diameter preselected to have an interference fit with the outer surface of said annular wall.

Claim 13

The connection structure of claim 9 wherein said rib further defines a constant thickness mid-portion.

Claim 14

The connection structure of claim 9 wherein said rib further defines a constant thickness mid-portion having an axial length greater than the axial length of said tapered end.

Claim 15

The connection structure of claim 9 wherein said annular element further defines a chamfered surface at said first end of said radially inner surface for facilitating pressing of said element coaxially onto said annular wall.