Closure mechanism for a door

A mechanism for securing a dome-shaped door in an opening of a vessel to effect sealing with respect to pressure at either side of the door, the convex side of the door being directed towards the exterior of the vessel and the mechanism being disposed at the concave side of the door and including locking members radially movable into a door locking position and a spider assembly connect to move the locking members and mounted for movement along a shaft carried by the door between a position in which the assembly is adjacent the door and the locking members are retracted from the door locking position and a position in which the assembly is spaced from the concave side of the door and the locking members are in the door locking position, whereby the mechanism can be retained substantially within the recess defined by the door at its concave side.

BACKGROUND OF THE INVENTION 
The present invention is directed to a door closure mechanism for securing 
a door in an opening provided in a wall of a vessel to seal the opening 
against pressure on either side of the door. The mechanism is particularly 
suitable for use on doors of undersea vessels. 
Various door closure mechanisms have been devised for locking a door in an 
opening provided in vessels, tanks or chambers of various types in a 
manner which provides a pressure tight seal. 
Vessels such as pressure chambers, retorts and the like, require seals 
which are designed to be outwardly effective, that is effective in the 
direction of from the inside to the outside of the vessel, while other 
vessels, such as vacuum chambers and the like, require seals that are 
inwardly effective, that is effective in the direction of from the outside 
to the inside of the vessel. In vessels useful in undersea manuevers, such 
as diving chambers, diver lock-out modules and other types of 
submersibles, the joint between the opening provided in the vessel wall 
and the door must be sealed against pressure exerted from either side of 
the door. 
The various door closure mechanisms presently used to secure a door on a 
vessel wall opening, such as disclosed in U.S. Pat. Nos. 2,219,137 to 
Moon, 2,355,475 to Skaller and 2,447,464 to Jenkins are of complex design. 
Such as door is normally of a circular configuration to give it added 
strength and rigidity to withstand the various forces exerted thereon, has 
a convex side protruding into the interior of the vessel, and has a 
rotatable shaft axially mounted on it. The shaft extends outwardly beyond 
the boundary of the vessel walls to provide sufficient movement of a 
spider assembly connected to the shaft to effect locking and unlocking and 
may extend inwardly beyond the convex surface to permit opening and 
closing from within the vessel. To effect locking, the spider hub of the 
assembly is required to move towards the door body to thereby actuate a 
series of lever arms or a series of combinations of lever arms to 
outwardly extend a locking device located at the junction of the periphery 
of the door and the vessel wall. The spider assembly may be designed with 
a series of lever arms attached to the hub, such as by a ball and socket 
arrangement, in a manner such that relative rotation between the hub and 
the shaft forces the levers to slide through a series of guides and 
mountings to engage keeper bars mounted on the vessel wall. 
The known closure mechanisms have the drawback of being of a fairly complex 
design and requiring space outside of the boundaries of the vessel walls 
for movement of the hub. In the case of undersea operations such 
protrusions beyond the vessel wall boundary create hazards in that such 
protrusions can entangle the vessel's life support umbilical cords and the 
like. 
Further, known closure mechanisms present a hazard to the occupants within 
the chamber of the vessel by the protrusion of the door and the shaft into 
the chamber. 
Still further, the known complex mechanisms ar susceptible to breakdown and 
malfunctioning which may abort the mission for which the vessel was 
intended. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide an improved 
door closure mechanism, especially suitable for undersea vessels, which is 
substantially contained within the envelope of the door and within the 
boundary defined by the vessel wall, which has a simple design with few 
moving parts, making it less susceptible to breakdown and malfunction, and 
which has a high mechanical advantage. 
These and other objects are accomplished by the present door closure 
mechanism which is able to secure a door in an opening provided in a wall 
of a vessel to seal the opening against pressure in both directions, the 
door having a dished configuration which is concave toward the inside of 
the vessel and having a shaft mounted thereon which extends axially of the 
opening and projects inwardly away from the concave side of the door and 
having a spider assembly which has locking members disposed around the 
periphery of the door movable into a position for locking the door to the 
opening, lever arms each having one end connected to a locking member and 
the other end connected to a spider hub which is mounted on and coacts 
with the axial shaft such that when the hub is adjacent to the door the 
lever arms and locking members are retracted inwardly to a door unlocking 
position and when the hub is away from the door the lever arms and locking 
members are extended radially outwardly in locking position, the shaft 
having a device, such as a wheel connected to the shaft, for rotating the 
shaft to cause the hub to move axially thereon. 
Further, the door can be circular with the lever arms extending radially 
substantially the radius of the door. Further the vessel wall has around 
the opening provided therein, a collar member which presents a surface 
radially extending and facing towards the interior of the vessel. The door 
has, around its periphery, a peripheral member which presents a surface 
radially extending in facing arrangement with the surface of the collar 
member and facing away from the interior of the vessel. One of these 
members has a sealing member connected thereto for sealing the door to the 
vessel wall. 
In further accordance with the present invention, the peripheral member is 
provided with radially extending holes and the collar member is provided 
with radially extending holes in facing arrangement with the holes of the 
peripheral member. The locking members extend only into the holes of the 
peripheral member when the hub of the spider assembly is positioned close 
to the door. The locking members extend through the peripheral member 
holes and into the collar member holes when the hub of the spider is 
positioned away from the door.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will now be described in detail with reference to the 
preferred embodiment illustrated in the FIGURE, which shows a vessel whose 
walls 1 are provided with an opening 2 arranged to be closed and sealed by 
a door 3. The vessel walls 1 may extend substantially perpendicular to the 
axis of opening 2, by curved to form a spherical element or may be 
oriented in any other direction suitable to conform to the design needs of 
the vessel. 
The door 3 has a dished, or dome-shaped, configuration which is concave 
toward the inside of the vessel chamber 5 and the closure mechanism is 
substantially contained within the recess defined by door 3 at its concave 
side. The door 3 is normally made of heavy metal plate and is circular. 
One edge of door 3 is provided with a hinge of any standard construction 
(not shown) to swing door 3 between closed and open positions. 
The dished configuration of the door is defined by the shape of formed 
plate 6 to present a concave surface 6' facing toward chamber 5 and a 
convex surface 6" facing away from chamber 5. At the center of plate 6 is 
a mounting member 7 for mounting a threaded shaft 8 to the door. The 
mounting member can be in the form of a support for mounting shaft 8 to 
extend, when the door is closed, along the axis 4 of the opening 2 so as 
to project inwardly away from the concave surface 6' of the door. The 
mounting member 7 can, as illustrated in the FIGURE, be a bushing member 
provided with accompanying sealing member 9 for permitting shaft 8 to 
extend through door 3 in a sealing manner so as to also extend axially 
outwardly to permit opening of the door from the exterior of the vessel. 
On shaft 8 is mounted a spider assembly 11 composed of a spider hub 12, 
lever arms 13, and locking members 14. Each of the locking members 14 is 
located at the periphery of the door 3 and is capable of moving radially 
outwardly and inwardly to lock and unlock, respectively, door 3 to the 
vessel wall 1. Locking members 14 are each, respectively, connected to one 
end of a lever arm 13 by a pin 15. The opposite end of each of the lever 
arms 13 is connected to the spider hub by a pin 16. Pins 15 and 16 connect 
the members in a manner which permits free movement of the members of the 
spider assembly 11 in response to the axial movement of hub 12 on shaft 8. 
When the spider hub 12 moves inwardly towards the concave surface 6' and 
into the envelope of door 3 it causes lever arm 13 and locking member 14 
to retract radially inwardly and cause locking member 14 to move into the 
door unlocking position. When the spider hub 12, on the other hand, is 
caused to move outwardly, the lever arms 13 and locking members 14 move 
radially outwardly, causing locking members 14 to move into the door 
locking position. 
The spider hub 12 has an axial hole 17 which is threaded to coact with the 
threaded shaft 8 in a manner that the rotation of the shaft 8 causes axial 
movement of hub 12. Handle 18 is connected by nut 19 to that end of shaft 
8 which is farthest away from the door to permit rotation of the shaft. 
The rotation can also be accomplished by other conventional means, such as 
an electric motor. 
If shaft 8 extends (as illustrated) through mounting member 7 to the 
exterior of the vessel, the shaft carries a further handle 20 located on 
the shaft to rotate the shaft 8 from outside of the vessel. 
The door 3 has a peripheral member 10 located at the periphery of plate 6. 
Peripheral member 10 has distributed around its circumference a series of 
holes 21 radially extending through the member 10 within which locking 
members 14 seat. Further, the peripheral member 10 provides a radially 
extending surface 22 which faces away from the interior chamber 5 of the 
vessel. 
The vessel wall 1 has a collar member 25 surrounding opening 2. The collar 
member 25 is connected to the vessel wall 1 by weldments 1'. Extension 
member 25' may extend outwardly away from the vessel wall 1 to conform to 
the design needs of the vessel. Distributed around the circumference of 
collar member 25 are radially extending holes 26 which are aligned with a 
respective hole 21 of peripheral member 10. 
A bearing member 27 in each hole 26 has a bearing surface 27' facing 
toward the exterior of the vessel. Members 27 may be an integral part of 
each of the holes 26 or may be separate members of suitable wear-resistant 
material connected therein. 
Collar member 25 also has a surface 29 facing towards chamber 5 which 
radially extends towards the center of opening 2 and which is in facing 
relationship with surface 22 of peripheral member 10 when the door is 
closed. 
Between surface 22 and surface 29 is a sealing member for establishing a 
pressure-tight seal between members 10 and 25, and hence between the door 
and the vessel wall. The FIGURE illustrates the sealing member connected 
to surface 22 in the form of an O-ring sealing member 23 of flexible 
material, such as rubber, which is partially housed in an annular groove 
24 in surface 22. 
The locking members 14 each have a tapered surface 28 which faces towards 
the interior chamber 5. When locking member 14 is in a locked position, 
the tapering surface 28 engages with bearing surface 27' of holes 26 to 
urge the door axially chamber 5 and thereby urge surfaces 22 and 29 into a 
locking engagement. 
The force produced by the camming action of locking members 14 against 
surfaces 27' assures maintenance of a pressure tight seal against pressure 
exerted from outside of the vessel, while the relative positions of 
surfaces 22 and 29 assures that pressures exerted from within the vessel 
will act on door 3 in a direction to urge surface 22 against surface 29, 
thereby maintaining a pressure tight seal. 
The present invention provides a locking and sealing mechanism which can be 
contained substantially within the envelope of the door and the region 
defined by the collar such that when the spider hub 12 is positioned close 
to the door plates 6 the locking members 14 are retracted inwardly via 
lever arms 13 and are not extending into holes 26. When the door 3 is 
closed and spider hub 12 is positioned away from plate 6 of door 3 the 
lever arms 13 are extended radially and, in turn, cause the locking 
members 14 to extend radially into holes 26 and against bearing surfaces 
27 to lock the door in opening 2 in a sealing manner. 
Because the door locking position of members 14 corresponds to the maximum 
separation of hub 12 from plate 6 and unlocking is effected by moving hub 
12 toward plate 6, maximum advantage is taken of the recess presented at 
the concave side of door 3 and the door locking mechanism need not 
protrude inwardly beyond that recess. 
The door closure mechanism may, alternately, be orientated in an opposite 
direction with respect to the chamber from that described hereinabove. The 
dished configuration of the door, thus, presents a concave surface away 
from the vessel chamber and a convex surface facing toward the chamber. 
The door closure mechanism of the door orientated in this manner has a 
reduced amount of protrusions than presented by conventional door closures 
presently in use. 
It is understood that the above description of the present invention is 
susceptible to various modifications, changes and adaptations, and the 
same are intended to be comprehended within the meaning and range of 
equivalents of the appended claims.