Door latch for electrical equipment enclosure

Details Door latch for electrical equipment enclosure Door latch for electrical equipment enclosure

1999-12-13

2002-03-19

Estremsky, Gary (Department: 3627)

Closure fasteners

Bolts

Hooked end

C292S067000

Reexamination Certificate

active

06357804

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to a door latch for an electrical equipment enclosure. In particular, this invention relates to a flexible door latch which can prevent the door of an electrical equipment enclosure from being forced open during a short circuit overcurrent condition without requiring bolts within the latch.
Electrical equipment enclosures such as those containing, for example, a motor starter, electric switch and a circuit breaker, require durable latches to prevent the enclosure door from blowing open under the arc gas pressure generated upon occurrence of a short-circuit overcurrent condition within any of the enclosed electric equipment. Such latches are often cumbersome due to the mechanical structure needed to withstand the explosive forces generated by the arc pressure on the enclosure door such that some time is required to unlatch the door during routine mechanical maintenance of the enclosed equipment.
One example of a door latch containing a pawl member bolted to a rotatable member is described within U.S. Pat. No. 5,927,766 entitled “Latching Mechanism for a Motor Control Center.”
It would be advantageous to provide a pair of compact latches to the door of a motor control center to allow a controlled outwards expansion of the door during intense short-circuit overcurrent conditions to allow arc pressure gas venting while maintaining the door in a virtually closed condition. However, the cumbersome prior door latches have made providing such a pair of latches on a single door significantly expensive in material, time, and labor.
BRIEF SUMMARY OF THE INVENTION
In an exemplary embodiment of the invention, a door latch for latching a door of an electrical equipment enclosure includes a latch body and a latch rod rotatable between locked and unlocked conditions. The latch rod includes a stem with a first end rotatably coupled to the latch body, an extension rod with a first end coupled to a second end of the stem, and a hook coupled to a second end of the extension rod. The extension rod is dimensioned to contact a portion of the electrical equipment enclosure when the latch rod is in the locked condition. The hook is separated form the portion of the electrical equipment enclosure by a clearance distance “x” during a quiescent condition within the electrical enclosure. The hook contacts the portion of the electrical equipment enclosure during a pressurized condition within the electrical equipment enclosure. The clearance distance “x” is selected to provide a clearance distance “y” between the door and the enclosure to allow pressurized gas to escape the enclosure during the pressurized condition.


REFERENCES:
patent: 849207 (1907-04-01), Cox
patent: 927240 (1909-07-01), Hoffman
patent: 1521699 (1925-01-01), Massuger
patent: 1664576 (1928-04-01), Stuart
patent: 1692295 (1928-11-01), Gerard
patent: 1822110 (1931-09-01), Raymond
patent: 2603511 (1952-07-01), Schatzman
patent: 2670981 (1954-03-01), Wenham
patent: 3402958 (1968-09-01), Barry
patent: 3482143 (1969-12-01), Stark
patent: 4337972 (1982-07-01), Gill
patent: 4586736 (1986-05-01), Dougherty
patent: 5791701 (1998-08-01), Daoud
patent: 5927766 (1999-07-01), Rosen

Affiliated with

Also associated with

Rating

Door latch for electrical equipment enclosure does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Door latch for electrical equipment enclosure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Door latch for electrical equipment enclosure will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2880069