Movable or removable closures – Bipartite – center opening – Overlapping meeting edges
Reexamination Certificate
2000-11-07
2001-06-26
Redman, Jerry (Department: 3634)
Movable or removable closures
Bipartite, center opening
Overlapping meeting edges
C312S324000
Reexamination Certificate
active
06250015
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to safety cabinets for storage of combustible, volatile or other hazardous materials and more specifically to safety cabinets having doors which are self-closing in a sequential order and are self-latching at three points following closing.
2. Description of Prior Art
Use of safety cabinets for storage of paints, solvents, lubricants and various other combustibles, volatile and hazardous materials is required by most safety regulations and fire codes. To isolate the interior of the cabinet and protect its contents from the heat and flames of a fire or to contain a fire within the cabinet, door(s) of a safety cabinet, in most cases, have a fusible link to trigger self-closing of the door(s) when the fusible link reaches a selected temperature. Cabinets having two doors utilize sequencing mechanisms to assure that a particular door closes prior to the other door so as to obtain a seal at a lip which extends from the edge of one of the doors and overlaps the other door.
To provide a more secure enclosure and maximize safety, a self-latching mechanism is utilized to latch the doors following self-closing. Most safety regulations require latching at three points on the cabinet. Examples of such self-latching mechanisms are described in U.S. Pat. Nos. 4,146,944 and 4,265,051, both with Williams as the inventor, which describe a “three-point latching mechanism” which includes a center latch and a pair of vertically oriented rods, a top rod extending from the latch mechanism to the top edge of the door and a bottom rod extending from the latch mechanism to the bottom edge of the door. When in latched position the center latch engages a second door and ends of the rods extend through apertures in the door frame. The mechanism is biased by a spring toward the latched position but is restrained from reaching that position by a notch in the bottom rod which fits over a bracket positioned on the door near the lower end of the bottom rod. The notch is biased to catch on the bracket by a leaf spring acting on the rod. When the door is closed the bottom rod contacts an upturned flange on the door housing to release the notch from the bracket and allow the latch and rods to engage.
U.S. Pat. No. 5,061,022 describes a latching mechanism which includes a latch spring biased to move to a latched position and a plurality of levers. The latch is prevented from latching by a locking pin engaged in a positioning lever slot. The pin is disengaged from the slot when an actuating lever contacts a jamb stop when the door is closed. The jamb stop is located in the side door jamb to which the door is hinged.
U.S. Pat. No. 4,262,448 describes a latching mechanism having a center latch and a top and a bottom latch rod which engages the top and bottom frame of the cabinet. The mechanism is spring biased toward a latched position. The top rod incorporates a shoulder which engages a latch bracket and a leaf spring biases the rod to maintain the engagement. Upon closing the door a latch stop in the top frame of the cabinet contacts the rod to dislodge the shoulder from the latch bracket which allows the biased latching mechanism to latch.
U.S. Pat. No. 4,619,076 describes a latching mechanism having a latch rod with an inclined upper end. The rod is spring biased toward an upward latched position. Upon closing of the door the inclined upper end of the rod contacts a top frame of the cabinet which forces the rod downward to pass by a corner of the frame and then engage an aperture in the frame when the door is completely closed.
SUMMARY OF THE INVENTION
The present invention provides, in a preferred embodiment, three point self-latching for a safety cabinet having two sequentially closing (a first-closing and a second-closing) side-by-side doors. The second-closing door has a rotatable bellcrank within its cavity which is attached to an exterior rotatable handle. The bellcrank has a protruding latching arm for engaging the first-closing door and two additional latching arms, each of which connects to a rod which extends through a frame of the cabinet to achieve latching. The bellcrank is biased to rotate toward a position at which such latching is achieved. Rotation to the latched position is prevented by an interference bar which is slidable from a position whereat it does not interfere with the latching arm to a position whereat it interferes with the latching arm. The bar is biased to the position at which it interferes with the latching arm. Upon sequential closing of the doors, a mechanism overrides the bias of the interference bar to slide the bar to a position of non-interference which then allows the bellcrank to rotate to the latched position thus achieving the three-point latching. Those and other specific features and contributions of the invention are described in more detail with reference being made to the accompanying drawings.
REFERENCES:
patent: 3822506 (1974-07-01), Fishbach
patent: 3919808 (1975-11-01), Simmons
patent: 4146994 (1979-04-01), Williams
patent: 4262448 (1981-04-01), Flider
patent: 4265051 (1981-05-01), Williams
patent: 4619076 (1986-10-01), Livingston
patent: 5061022 (1991-10-01), Meriwether
patent: 5944399 (1999-08-01), Gillispie
patent: 5992098 (1999-11-01), Flider et al.
Armstrong Westerman Hattori McLeland & Naughton LLP
Eagle Manufacturing Company
Redman Jerry
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