Pipe joints or couplings – Movable jaw
Reexamination Certificate
2000-06-20
2002-01-01
Swann, J. J. (Department: 3611)
Pipe joints or couplings
Movable jaw
C285S323000
Reexamination Certificate
active
06334634
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an improved-push-to connect tubing fitting for engaging nylon tubing or tubing of like material. More specifically, the improved push to connect tubing fitting seals the tubing connection prior to mechanical engagement of the tubing to the fitting Upon insertion in the fitting, the tubing engages a sealing means prior to engaging the tubing gripping devices of the collett.
PRIOR ART
The purpose of the prior art push-to-connect tubing fittings is to allow assembly and disassembly of tubing connections without tools and as rapidly as possible. The tubing has a soft exterior and is circular in cross section. An example of a prior art tubing fitting with tubing assembled within the fitting is shown in FIG.
5
. The prior art fittings
10
had a body
11
with a bore
12
in it. A collett
13
was positioned within the bore
12
of the body
11
to mechanically engage the nylon tubing
20
upon its insertion. The collett
13
had a bore
15
extending along the same axis as the bore
12
of the body
11
and all the way through the collett
13
. Tubing gripping devices
16
were present on the inner surface of the bore
15
in the collett
13
, at the end of the bore opposite the tubing insertion opening. The diametrical distance between radially opposite tubing gripping devices
16
was slightly less than the diameter of the outer surface of the tubing
20
. Thus when the tubing
20
was inserted into the fitting
10
, the end of the collett
13
opposite the tubing insertion opening was elastically deformed radially outward and the tubing gripping devices
16
engaged the outer diameter of the nylon tubing
20
.
The prior art tubing fitting
10
had further structure to more positively engage the tubing
20
to the fitting
10
. Radially outward of the tubing gripping devices
16
the collet
13
had ramped surfaces
24
on its outer surface which sloped toward the axis of the bore
15
in the collett
13
in the direction from the end farther from the insertion opening to the end closest to the insertion opening. The body
11
of the fitting
10
defined ramped surfaces
25
adjacent its inner bore
12
which also sloped toward the axis of the bore
12
from their end furthest from the tubing insertion opening to their end closest to the tubing insertion opening. The collett
13
was positioned in the body
11
of the fitting
10
such that the ramped surfaces
24
on its outer surface were disposed adjacent to but radially inside and further from the tubing insertion opening than the ramped surfaces
25
defined by the inner surface of the body
11
of the fitting
10
. Thus, after the nylon tubing
20
was inserted into the fitting
10
the gripping devices
16
of the collett
13
would engage the nylon tubing
20
. If thereafter, a force was applied to the tubing
20
in the proper direction to remove the tubing
20
from the fitting
10
, the tubing
20
and the collett
13
would be forced as a unit toward the tubing insertion end of the fitting
10
. This brought the ramped surfaces
24
on the outer surface of the collett
13
into facial engagement with the ramped surfaces
25
on the inner surface of the body
11
of the fitting
10
and caused the end of the collett
13
opposite the tubing insertion opening to constrict radially inward. Under such circumstances the inward force of the tubing gripping devices
16
on the tubing
20
was increased and the strength of the mechanical engagement between the tubing
20
and the collett
13
was further increased. In many instances a rigid cylindrical sleeve
27
was fixedly attached to the body
11
of the fitting
10
concentrically within the bore
12
of the body
11
. This sleeve
27
protruded into the bore
12
of the body
11
toward the outer end of the fitting
10
. The outer diameter of the sleeve
27
was slightly smaller than the inner diameter of the nylon tubing
20
. When the tubing
20
was inserted into the fitting
10
, the end of the tubing
20
slid over and surrounded the free end of the sleeve
27
. The sleeve
27
thus supported the inside of the tubing
20
and prevented the tubing
20
from collapsing inward as increased force was applied to the outside of the tubing
20
by the tubing gripping devices
16
of the collett
13
.
The sealing device
44
of the prior art tubing fitting
10
was disposed farther from the tubing insertion opening than were the tubing gripping devices
16
of the collett
13
. The prior art fitting
10
had the sealing device
44
positioned co-axially inside the bore
12
of the body
11
at a point farther from the tubing insertion opening than the tubing gripping devices
16
of the collett
13
. Thus as the tubing
20
was inserted into the fitting
10
, it would first engage the tubing gripping devices
16
of the collett
13
, and then as it was inserted farther into the fitting
10
it would sandwich the sealing device
44
between the outer surface of the tubing
20
and the bore
12
of the body
11
. This effectively sealed the tubing
20
to the fitting
44
. The tubing gripping devices
16
of the collett
13
often marred the outer surface of the tubing
20
which was to seal against the sealing device
44
. In addition, the tubing
20
was often inserted into the fitting
10
far enough to engage the tubing gripping devices
16
of the collett
13
but not far enough to engage the sealing device and the connection would leak.
SUMMARY OF INVENTION
As a result,—an object of the present invention is to provide a fitting which allows quick, easy assembly and disassembly of a tubing connection without the use of tools and to further ensure that the tubing cannot be mechanically engaged by the fitting without being sealed to the fitting. A second object of the invention is to provide a fitting which does not mar the portion of the outer surface of the tubing which engages the sealing device.
The fitting of the present invention is similar to the fittings of the prior art. The fitting of the present invention has a body with a bore in it. A collett is positioned within the bore of the body and has a bore through it approximately parallel to the bore of the body. The collett has tubing gripping devices on the inner surface of its bore. A sealing device is positioned co-axially inside the inner bore of the collett at a point closer to the tubing insertion opening than are the tubing gripping devices of the collett. Another sealing device is positioned between the outer surface of the collett and the inner surface of the bore in the fitting body. Thus, when the tubing is inserted into the fitting, it first engages the sealing device on the inside of the collett and after it is further inserted into the fitting mechanically engages the tubing gripping devices of the collett. This causes the tubing to be sealed to the collett before it is mechanically engaged to the fitting. The sealing device positioned between the collett and the body of the fitting seals the collett to the body of the fitting and thus completes the sealing of the tubing to the fitting The use of a sealing device between the collet and the body is an alternative to different structures which effectively complete the sealing of the tubing to the fitting but make it necessary to use tools to disassemble the tubing from the fitting.
It can thus be seen that above described device accomplishes both of the objects of the invention. The first object is accomplished because the tubing must be inserted into the fitting far enough to engage the sealing device inside the bore of the collett before it engages the tubing gripping devices of the collett. Thus it is not possible to insert the tubing into the fitting tar enough to mechanically engage the fitting without the tubing having first engaged the sealing device inside the collett. The second object is accomplished because the portion of the outer surface of the tubing which engages the sealing device inside the collett has not contacted the tubing gripping devices of the collett and thus has not been m
Calfa Jeffrey P.
International Truck and Engine Corporation
Lum L.
Powell Neil T.
Sullivan Dennis Kelly
LandOfFree
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