Fluent material handling – with receiver or receiver coacting mea – Filling means with receiver or receiver coacting means – Interlocked discharge means – support and/or coupling
Reexamination Certificate
2000-07-21
2002-06-18
Jacyna, J. Casimer (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Filling means with receiver or receiver coacting means
Interlocked discharge means, support and/or coupling
C141S348000, C141S351000, C141S384000, C141S386000, C137S614000, C137S614190, C251S263000
Reexamination Certificate
active
06405768
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to pressure fuel servicing nozzles for mating with a standardized aircraft fueling adapter having a cylindrical extension with a plurality of indexing notches and a plurality of radially extending lock tabs.
BACKGROUND OF THE INVENTION
An aircraft fuel system includes a fuel line which terminates in an exposed fueling adapter at the fuel input point. Refueling facilities include a stationary or mobile fuel supply having an extended large diameter hose or articulated pipe and various pumps for delivery of the fuel under pressure. A pressure fuel servicing nozzle is secured to the delivery end of the fuel hose or pipe and is mechanically configured to engage and receive the fueling adapter. The fuel servicing nozzle is required to perform several basic mechanical functions which include mechanically engaging and locking with the fueling adapter, providing a high pressure fuel seal between the fuel delivery hose and the aircraft fuel system, and properly valving the fuel flow between the fuel system and the aircraft to provide open flow and closed seal conditions to facilitate fueling and the termination of fueling. In addition to these basic functions, modern fuel servicing nozzles provide various safety mechanisms directed toward the prevention of fuel spillage and leakage. This is critical to the operation of such refueling systems due to the highly volatile and flammable character of aircraft fuels. One such safety mechanism provides an interlock within the fuel service nozzle which prevents opening a flow control poppet valve until the nozzle has completed proper mechanical and sealing engagement with the fueling adapter.
Referring to
FIG. 1
, a standardized fueling adapter
2
for commercial and military aircraft is shown. The fueling adapter
2
includes a cylindrical extension
4
with three rectangular shaped indexing slots
6
having flat engaging surfaces
7
. Three lock tabs
8
extend radially outwardly from the cylindrical extension
4
and an adapter poppet valve
10
is biased in a closed position to prevent fuel flow. Due to the physically demanding operating environment of refueling an aircraft, which involves handling relatively long and heavy fueling hoses under a variety of situational urgencies as well as all weather conditions, the engagement surfaces of the lock tabs
8
are usually ramped and radiused to enable an operator to readily engage and rotate the fuel nozzle onto the fueling adapter
2
, wherein scuffing or binding of the engagement mechanism of the fuel nozzle against the lock tabs
8
is reduced. Another benefit of providing ramped and radiused lock tabs
8
is the reduction in wear of the engagement mechanism.
Generally, existing fuel servicing nozzles comprise a rotating collar rotatably mounted upon a nozzle body which receives and locks with the fueling adapter to provide engagement. An interlock system prevents the opening of the flow control poppet valve within the nozzle body until mechanical engagement as evidenced by the rotational position of the collar is obtained. A receiving portion of the fuel nozzle receives and engages the fueling adapter
2
, and the interlock system includes an interlock plate which prevents rotation of the collar in the absence of the insertion of the fueling adapter
2
. The interlock plate is generally a flat ring shaped member which is biased onto a bayonet ring embedded within the collar. When the fuel nozzle is not connected to the fueling adapter
2
, the engagement surfaces of the interlock plate abut against the blocking walls extending outwardly from the inner surface of the bayonet ring.
To connect the fuel nozzle to the fueling adapter
2
an operator aligns three locating pins of the fuel nozzle with the indexing slots
6
of the fueling adapter
2
. When the fuel nozzle is aligned, the fuel nozzle can be pushed into the fueling adapter
2
, thereby depressing the interlock plate away from the inner surface of the bayonet ring to clear the blocking wall and allowing the collar to be rotated about the nozzle body. After full rotation of the collar, an operating handle is now free to be rotated to open the flow control poppet valve. Of particular note is that the ramped and radiused lock tabs
8
may allow rotation of the collar prior to full depression of the interlock plate. This partial depression of the interlock plate by an incomplete engagement allows the start of the rotation of the collar. Furthermore, the interlock system is designed to disengage under a less than full depression of the interlock plate because of timing issues dealing with the physical relationship of the axial movement of the interlock plate with respect to the rotational movement of the collar as defined by the ramped and radiused lock tabs. Thus, the height of the blocking surface is. usually substantially less than the clearance provided by a full depression of the interlock plate.
The features discussed above to allow easy coupling of the fuel nozzle to the fueling adapter
2
effects the safety of the connection because the nozzle body may not be held in the correct position when the collar is being rotated about the fueling adapter during both connection and disconnection. A situation may arise where the fuel nozzle is connected to the fueling adapter
2
where the longitudinal axis of the fuel nozzle is slightly skewed with the longitudinal axis of the fueling adapter
2
. As a result, a gap may exist in the fuel seal between the contacting surfaces of the fuel nozzle and fueling adapter
2
. If the improper connection sufficiently depresses the interlock plate to clear the blocking walls of the bayonet ring, the interlock system may be defeated and an operator may be able to rotate the operating handle and open the fuel nozzle, and a dangerous fuel spill may result.
In another possible situation, the fuel nozzle may be properly aligned and coupled to the fueling adapter
2
, but the lock tabs
8
of the fueling adapter
2
may be worn to the extent that the fuel nozzle may be removed from the fueling adapter
2
under an unsafe condition such as when the collar assembly is not fully rotated in the closed direction with respect to the body when disconnection from the fueling adapter
2
occurs, due to worn lock tabs
8
which exhibit thinning in critical regions. In this case, the interlock plate does not return to the locking condition and the abutting surfaces of the bayonet ring and the interlock plate are not mated. With the interlock feature so defeated, the collar can be rotated back to the open position when not attached to the fueling adapter
2
, thereby allowing the operating handle to then be rotated to open the nozzle.
Another problem which may arise in existing fuel servicing nozzles is the unintentional disengagement of the flow control poppet valve from the fully open position to an intermediate open position during the refueling process. When the fuel nozzle is connected to the fueling adapter
2
, rotation of the operating handle causes the flow control poppet valve to be pushed into the fueling adapter
2
and consequently pushes open the corresponding spring loaded, adapter poppet valve
10
. The spring from the adapter poppet valve maintains both poppet valves in intimate contact and applies a force in the upstream direction that keeps the internal components of the fuel nozzle in the fully open position, due to an over-center locking condition of a crankshaft. During relatively high flow rates, the adapter poppet valve
10
may be pushed further in the downstream direction by the flowing fuel impinging on the adapter poppet valve
10
. Intimate contact between the poppet valves is disrupted, and the flow control poppet valve no longer receives a force in the upstream direction from the adapter poppet valve. Consequently, the flow control poppet valve and related internal components are free to rotate and/or travel to a position other than the fully open position.
Typically, it is highly desireable to refuel an aircraft as quickly as possib
Cla-Val Co.
Jacyna J. Casimer
Oppenheimer Wolff & Donnelly LLP
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