Pipe joints or couplings – Particular interface – Annular socket
Reexamination Certificate
1997-06-26
2001-07-31
Luu, Teri Pham (Department: 3627)
Pipe joints or couplings
Particular interface
Annular socket
C285S376000
Reexamination Certificate
active
06267418
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to an attachment for securing pressure sensitive controls to systems which operate under high or low pressures, or both, and more particularly, to a threadless coupling for securing pressure sensitive switches to such systems.
Generally, in systems which operate under high or low pressures, or both, pressure sensitive controls responsive to predetermined high or low pressures are utilized to enhance system performance. Such controls also increase the system operating life by controlling the pressure within the system to be within a predetermined range. For example, in automotive air conditioning systems which include a compressor extremely high pressures can adversely affect the operating life of the compressor and other components within the system. To prevent the pressures within such systems from reaching such high magnitudes, a pressure sensitive control responds to a predetermined high pressure by, for example, de-energizing the compressor. When the pressure within the system returns to a predetermined safe level, the pressure sensitive control responds by energizing the compressor.
Many known pressure sensitive controls have been used with such pressurized systems. One example of such a control is described in Hogue et al., U.S. Pat. No. 5,300,741, which is assigned to the present assignee. Known pressure sensitive controls such as the control described in Hogue et al. include a snap-disc normally biased in a first position which “snaps” to a second position in response to a predetermined pressure within a pressurized system. A movable contact and a stationary contact are included within the control. The movable contact moves in response to the movement of the snap-disc.
In a typical application, the pressure sensitive control is coupled between an energy source and a compressor clutch of the pressurized system. Under normal conditions, the moveable contact engages the stationary contact in a circuit-making condition and the compressor is energized. If the pressure within the system exceeds a predetermined level, the snap-disc “snaps” to the second position causing the moveable contact to move away from the stationary contact into a circuit-breaking condition. In the circuit-breaking condition, energy to the compressor is cut off thereby preventing the pressure within the system from increasing. When the pressure within the system returns to a predetermined safe level, the snap-disc returns to its normal position, i.e., the first position, the movable contact again engages the stationary contact, and the compressor is energized.
In addition to controlling energization of the compressor motor, such switches also are used to control compressor cycling and cooling fans and low pressure cut-outs. For example, with respect to low pressure cut outs, when the system pressure falls below a predetermined level, the control causes the system compressor to be de-energized.
Known pressure sensitive controls are attached to pressurized systems by threaded couplings. The manufacture of threaded components for the couplings involves cutting, rolling, tapping or, in the case of plastic parts, molding thread details in the parts. These operations are expensive, regardless of the method or type of material used. The assembly expense of threaded components is also high because proper mating of threaded components requires special tooling for tightening the components to a specific torque. The tooling and torque requirements also increase the time required for assembly and disassembly.
In addition to the time and expense associated with threaded members, problems can arise during assembly such as cross-threading or over stressing. Compensation for over stressing can been achieved through the use of metal components due to their increased strength over plastic components. However, the use of metal components results in higher manufacturing expense.
In an attempt to overcome the problems with threaded couplings, threadless couplings have been used in some applications. Various known threadless couplings are illustrated in
FIGS. 1-3
. Specifically,
FIG. 1
illustrates a coupling
20
for an air conditioning system including first and second tubular members
22
and
24
. First tubular member
22
includes a first passageway
26
, and two o-rings
28
,
29
are inserted in annular grooves formed in outer surface
30
of such member
22
. First tubular member
22
also has a spring retaining housing
32
with a spring
34
therein. Second tubular member
24
includes a second passageway
36
and, at its mating end, forms a lip
38
.
To engage first and second tubular members
22
and
24
, lip
38
of second member
24
is inserted into housing
32
and forced under spring
34
. Spring
34
retains lip
38
within housing
32
. A snap ring
40
may be fit over spring
34
and into engagement with housing
32
.
Another known coupling
50
is illustrated in FIG.
2
. Coupling
50
may be used in connection with speedometer cable for an automobile. Coupling
50
includes a connector
52
which receives a mating member
54
attached to one end of the speedometer cable. Connector
52
includes a passageway
56
. One end of passageway
56
is enlarged. A slot
60
is formed in connector
52
and a substantially u-shaped resilient wire retaining member
62
is inserted through slot
60
. Mating member
54
has an annular flange
64
formed at an intermediate location along its length.
To engage mating member
54
with connector
52
, mating member
54
is inserted into passageway
56
. Flange
64
is inserted through resilient retaining member
62
, which expands to allow flange
64
pass therethrough. Once flange
64
is inserted through member
62
, member
62
contracts to its normal configuration. Cooperation of flange
64
and retaining member
62
maintains engagement between mating member
54
and connector
52
.
A coupling
70
for an automobile fuel filter is illustrated in
FIG. 3. A
connector
72
is engaged to tube
74
having a passageway
76
. Specifically, ridges
78
are formed on a tubular extension
80
of connector
72
, and tube
74
is pushed over ridges
78
. Connector
72
also includes an opening
82
and a passageway
84
sized to receive a tubular extension
86
of a fuel filter. Two o-rings
88
,
89
are mounted in grooves formed in passageway
84
. An annular flange
90
is formed at an intermediate location along tubular extension
86
. A plastic clip
92
is inserted through openings
94
formed in connector
72
. Clip
92
cooperates with flange
90
to maintain tubular extension
86
and connector
72
in engagement.
Although such threadless couplings are useful in some applications, there still exists a need for a threadless coupling that can be utilized in both high and low pressure controls and in connection with fluid flow valves, such as a Schrader valve, if desired. A Schrader valve, for example, allows replacement of a switch in a pressurized system without having to evacuate and re-charge the system. Further, there exists a need for such a threadless coupling that is inexpensive to manufacture and is easy to assemble and disassemble.
Accordingly, it is desirable and advantageous to provide a coupling for pressure sensitive controls that does not require the use of threaded members. It also is desirable and advantageous to provide a coupling for both high and low pressure sensitive controls that is inexpensive to manufacture and simple to assemble and disassemble.
SUMMARY OF THE INVENTION
In an exemplary embodiment, a threadless coupling assembly includes a nut member and a mating member which can be quickly and easily assembled and disassembled. The nut member includes a first axial end which attaches to a pressure sensitive control. An opening is formed in the first axial end of the nut member. A substantially cylindrical housing having an outer surface and an inner surface extends between the first axial end and a second axial end of the nut member. A pair of openings spaced 180° apart are provid
Hogue Ronald Lee
Renkes Kenneth Ray
Armstrong Teasdale LLP
General Electric Company
Horton, Esq. Carl
Luu Teri Pham
Wasserbauer Esq. Damian
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