Closure fasteners – Bolts – Swinging
Reexamination Certificate
2000-11-28
2003-01-07
Swann, J. J. (Department: 3677)
Closure fasteners
Bolts
Swinging
C292S044000, C292S163000, C292S203000, C292S210000, C292S256500, C292SDIG003, C292SDIG003, C292SDIG005, C292SDIG006
Reexamination Certificate
active
06502871
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to latches useful in providing controlled operation of a panel or hatch and, more particularly, to a latch operated by rotational movement of the latch mechanism.
BACKGROUND
Hatches are often used to provide controlled access to a compartment or other area. For example, hatches are used in the marine industry to provide an enclosed area which may be easily accessed through manipulation of a hatch door or similar panel. Such hatches are often relied upon to keep objects in the enclosed area until needed and/or to provide for the safe storage of such objects, free from environmental and other elements. In the marine industry, environmental elements from which protection is sought may include damaging solar rays, moisture (such as corrosive salt water spray), and/or movement, such as that associated with a marine vessel in movement over water.
One typical hatch design in common use today includes a hatch door or panel having a hinge mechanism disposed along one edge to facilitate controlled movement of the hatch door between an open and a closed position. Additionally, the typical hatch design generally employs a latch mechanism disposed along an edge of the hatch door or panel to allow the hatch to be maintained in the closed position.
One such hatch and latch arrangement is shown in commonly assigned U.S. Pat. Nos. 5,231,948 and 5,358,291, both entitled “Hatch with Improved Latch and Hinge Assembly,” the disclosures of which are hereby incorporated herein by reference. The latch mechanism provided in the above referenced patents provides a linearly moving biased latch pawl which engages a frame or panel into which the hatch door is set to thereby provide a force to maintain the hatch in the closed position. This latch mechanism is sometimes referred to as a “slam latch” because of its ability to close and engage with the closing motion of the hatch door. The hatch and latch mechanisms of these embodiments are provided in plastics, such as may include ultra-violet light inhibitors or other protective additives, or other non-corrosive materials to provide a system adapted to withstand such environmental elements as sun and moisture.
Another latch mechanism often found on such hatch assemblies involves a rotatably mounted bolt to engage a frame or panel into which the hatch is mounted. Such a latch mechanism is sometimes referred to as a “dog down latch” because of its aggressive retention of the hatch in the closed position.
Directing attention to
FIG. 1
, hatch
100
is shown including latch
120
employing a typical prior art “dog down latch” embodiment. Specifically, hatch
100
includes hatch door
110
coupled to frame
130
by hinges
111
. Disposed along an edge opposite that of hinges
111
is latch
120
including bolt
121
disposed to engage frame
130
when hatch door
110
is in a closed position and, therefore, maintain hatch
100
in the closed position. In order to allow the opening and closing of hatch door
110
, bolt
121
is mounted on shaft
122
which is rotatably disposed through hatch door
110
. D ring
123
may be gripped by a user of hatch
100
and, thereby, rotational force may be applied to shaft
122
to cause bolt
121
to engage or disengage frame
130
as desired.
In order to allow hatch
100
to be disposed on a deck, bulkhead, or other surface with as nearly a flush surface as possible, hatch door
110
may include recess
112
in which shaft
122
is disposed. However, in order to operate hatch
100
, the user must pivot D ring
123
from within recess
112
in order to provide D ring
123
in a proper orientation to allow the user to provide sufficient rotational force to the latch. Thereafter, the user must pivot D ring
123
to return it to within recess
112
so as not to cause D ring
123
to extend beyond the surface of hatch door
110
, such as might present a trip or snag hazard on a deck or bulkhead.
It should be appreciated that the visible portion of latch
120
when hatch
100
is closed includes only shaft
122
and D ring
123
. Accordingly it is often not possible to determine when bolt
121
has engaged frame
130
as the appearance of shaft
122
and D ring
123
are substantially identical when bolt
121
has engaged frame
130
and when bolt
121
is disposed in an orientation 180° from engaging frame
130
. Accordingly, a user can often attempt to latch hatch
100
and later discover that the hatch is not in fact latched.
Although a “dog down” type latch typically provides sufficient retention of the hatch door against the frame or panel into which it is mounted to provide an adequate seal against water infiltration around the hatch door, the latch itself is an area of potential water infiltration. Specifically, as the shaft or attached mechanism must penetrate the surface of hatch door
110
in order to couple with bolt
121
, and there must be sufficient clearance for rotation of the shaft, there is a space through which water may pass. Accordingly, prior art solutions have typically engaged an O ring, made of a rubber or other resilient material, disposed around a portion of the shaft to engage a shaft hole edge in the hatch door to discourage water infiltration. The O ring is often disposed in such a way as to have substantial continuous and/or unequal pressure applied from the surfaces of the hatch door and/or the shaft both during rotation of the latch and when the latch is at rest. This pressure can result in premature failure of the seal as the friction often causes the material of the O ring to wear away. Similarly, often the water being discouraged from infiltration carries with it abrasive particles, such as sand and/or salt brine, further accelerating the wearing away of the seal. Moreover, the design of the latch assembly typically results in this O ring providing substantially the only defense to water infiltration.
Although not illustrated in the embodiment of
FIG. 1
, hatch
100
may be provided with a locking mechanism to discourage unauthorized access to an area enclosed thereby. It is difficult to employ a keyed locking mechanism on the shaft providing the rotational movement of the bolt. Accordingly, such locking mechanisms are often disposed separately from the latch, such as a separate lock cylinder and bolt disposed along an edge of the hatch door. Such an embodiment allows operation of the latch assembly, and thus its disengagement with the frame, relying upon the bolt of the locking mechanism to prevent opening of the hatch. Such an arrangement generally does not provide the level of security available with actually locking the latch mechanism. Additionally, prior art mechanisms are generally provided utilizing metal components which are prone to deterioration, such as through corrosion and/or rust when used in a marine environment. The prior art locking mechanisms also provide additional areas of potential water infiltration.
Accordingly, a need exists in the art for a latch system adapted to provide secure closing of a hatch door, even in rough and jarring movement, and to inhibit moisture from entering the enclosed area. A need exists in the art for the latch system to provide positive indication to a user of its engaged or disengaged status. Additionally, a need in the art exists for such a latch system to provide a substantially flush surface without requiring an operator to manipulate portions thereof to achieve such a flush surface. Moreover, a need exists in the art for the latch system to resist deterioration due to environmental elements.
A further need exists in the art for a latch system providing locked access such that persons not authorized to access the enclosed area are discouraged from opening the hatch door. A need in the art exists for a latch locking mechanism to be resistant to degradation, such as through exposure to environmental elements.
SUMMARY OF THE INVENTION
These and other objects, features and technical advantages are achieved by a system and method which employs a rotatable latch mechanism which is provided i
Fulbright & Jaworski L.L.P.
Lugo Carlos
Swann J. J.
Tempress Products, LP
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