Closure fasteners – Bolts – Hooked end
Reexamination Certificate
1999-10-05
2001-08-28
Estremsky, Gary (Department: 3627)
Closure fasteners
Bolts
Hooked end
C292SDIG003, C244S129400
Reexamination Certificate
active
06279971
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the mechanical arts. In particular, this invention relates to a latch with sensor that releasably engages a keeper, for securing two members, typically aircraft panels, to one another.
2. Discussion of the Related Art
Various types of latches join and lock aircraft panels, such as, aircraft cowlings, to one another. A typical latch includes a hook mounted to one aircraft panel that engages a keeper mounted to another aircraft panel. Further, the latch includes a handle to actuate the hook. The latch secures the aircraft panels to one another when the handle is in the closed position and the hook is engaged with the keeper. When the handle is in the closed position, the handle should be flush with the exterior surface of the aircraft panel to provide a visual indication that the latch is closed.
A problem with these latches is that, even when the handle is in the closed position, the hook may not be engaged with the keeper. For example, the hook or the keeper could be missing or broken. Unfortunately, the ground crew inspecting the aircraft cannot visually verify whether the hook has engaged the keeper to ensure the latch is properly closed. Various types of special devices, such as, a feeler mechanism, have been utilized with these types of latches to provide a visual indication of the hook and keeper engagement. Feeler mechanisms are typically mounted to the hook and detect whether the hook has engaged the keeper. If the hook does not engage the keeper, the feeler mechanism is translated to a blocking position which prevents the handle from closing. Thus, the handle is not flush with the exterior surface of the aircraft panel providing a visual flag that the latch is not properly closed. On the other hand, if the hook does engage the keeper, the feeler mechanism is translated to an unblocking position allowing the handle to close.
FIG. 1A
is a side view of a prior art latch
2
properly engaged to a keeper
3
, particularly illustrating a feeler mechanism
4
in the unblocking position. The latch includes a handle
5
, a spring
8
, a trigger lock
6
, pins
10
and
11
, and a hook
7
. The hook includes a hooked end
9
for engaging the keeper. The handle is moveable between a closed position and an open position, with the spring biasing the handle towards the open position.
The feeler mechanism
4
fits over the hook
7
and slides relative to the hook. The feeler mechanism is generally U-shaped in cross-section and has a pair of hooked portions
13
. The hooked portions align with the hooked end
9
of the hook. The feeler mechanism includes a notch
14
that cooperates with a handle pin
15
mounted to the handle
5
. The feeler mechanism also includes a pair of slots
16
and
17
that align with and enclose the pins
10
and
11
, respectively, which extend transversely through the hook. The slots allow the feeler mechanism to slide along the hook. The feeler mechanism further includes a pair of the secondary springs
18
and a pair of posts
19
that extend perpendicularly from the feeler mechanism. The secondary springs couple each pin with each post, respectively. The secondary springs bias the feeler mechanism towards the blocking position.
When the latch
2
is properly closed, the hooked end
9
and the hooked portions
13
engage the keeper
3
resulting in the feeler mechanism
4
sliding longitudinally relative to the hook
7
opposing the spring action of the secondary springs
18
. The feeler mechanism slides to the unblocking position such that the notch
14
aligns with the handle pin
15
. Then the handle pin falls into the notch allowing the trigger lock
6
to engage the protruding ends of the pin
10
and allowing the handle
5
to pivot to the closed position. In the closed position, the handle is flush with the exterior surface of the aircraft panel. Therefore, the feeler mechanism allows the handle to close, providing a visual indication that the hook has engaged the keeper and that the latch is properly closed.
FIG. 1B
is a side view of the prior art latch
2
disengaged from the keeper
3
illustrating the feeler mechanism
4
in the blocking position. When the hooked end
9
and the hooked portions
13
do not engage the keeper, the feeler mechanism does not slide longitudinally relative to the hook. The secondary springs
18
then bias the feeler mechanism to the blocking position. In the blocking position, the handle pin
15
does not align with the notch
14
, thus preventing the handle pin from falling into the notch. Therefore, the trigger lock
6
cannot engage the pin
10
and the handle
5
cannot pivot to the closed position. The spring action of the spring
8
then pivots the handle away from the exterior surface of the aircraft panel, towards the open position, such that the handle is angled relative to the aircraft panel. Therefore, the feeler mechanism, through the position of the handle, provides a visual indication that the hook has not engaged the keeper and that the latch is not properly closed.
Unfortunately, the prior art latch with the feeler mechanism suffers from certain disadvantages. Because pins extend through the hook to accommodate the feeler mechanism, the flight load capabilities of the latch are limited. Furthermore, the feeler mechanism is complex and uses many different parts. The feeler mechanism requires a specialized form fitting sheet metal part having many different surfaces and slots, along with secondary springs, all of which must cooperate with existing structures on the latch. For example, the notch must cooperate with the handle pin. This results in a latch that is relatively heavy and complex.
In view of the above, it should be appreciated that there is a need for a latch with sensor that provides a visual indication of the engagement of the hook and keeper, is mounted independently of the hook, and that is relatively light in weight and simple in design. The present invention satisfies these and other needs and provides further related advantages.
SUMMARY OF THE INVENTION
The invention resides in a latch with sensor that provides advantages over known latches in that it provides a visual indication of the engagement of the hook and keeper, is mounted independently of the hook, and is relatively light in weight and simple in design.
The latch releasably engages a keeper for securing two members to one another. The latch includes a handle moveable between a closed position and an open position and a hook pivotally connected to the handle for engagement with the keeper. The latch includes a trigger lock pivotally mounted to the handle for engagement with the hook so that when the handle is in the closed position, the trigger lock engages the hook, and when the handle is in the open position, the trigger lock is disengaged from the hook. To close the latch, the handle is rotated to the closed position and the hook engages the keeper securing the two members to one another. On the other hand, to open the latch, the trigger lock is disengaged from the hook and the handle is rotated to the open position such that the hook disengages from the keeper.
The latch includes a sensor that provides a visual indication, via the position of the handle, of the state of engagement of the hook and keeper. The sensor is mounted to the handle for movement between a blocking position and an unblocking position. The sensor has a sensing end for engagement with the keeper and a blocking end for engagement with the trigger lock. In some embodiments, the sensor is pivotally mounted to the handle and includes a blocking wall, defining the blocking end, and two depending legs defining the sensing end. If the handle is rotated towards the closed position and the depending legs do not engage the keeper, the sensor moves to the blocking position such that the blocking wall engages the trigger lock thereby preventing the trigger lock from engaging the hook and the handle from closing. The handle then pivots towards the open position providing a visual in
Barnes & Thornburg
Estremsky Gary
Hartwell Corporation
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