Patent Application
20180238087
This invention relates to National Electrical Manufacturers Association (NEMA) enclosures, and, more particularly, to an improved latch assembly for such enclosures that automatically locks when the front panel is closed.
NEMA enclosures are widely used in industrial and other applications to house hazardous parts. There are many types of NEMA enclosures, for indoor and/or outdoor use, which are categorized by numeric designation in accordance with their construction. For example, some NEMA enclosures are rated to provide mere access to hazardous parts, while others provide protection against ingress of solid foreign objects (falling dirt, circulating dust, lint, fibers etc.); ingress of water (hose down, splashing, occasional temporary submersion, occasional prolonged submersion); oil and coolant seepage, spraying and splashing; ingress of corrosive agents, and, other conditions. In order for an enclosure to receive a NEMA rating, strict construction standards promulgated by NEMA must be met.
Standards of construction for NEMA enclosures may also be employed in boxes or other containers for the storage of equipment, tools and the like in which protection against the types of conditions described above is desired. Boxes of this type, and NEMA enclosures generally, typically comprise a top panel, a bottom panel, a back panel and opposed side panels which are interconnected to form an interior. A front panel is hinged to the bottom panel and movable between open and closed positions. A seal is created between the front panel and the edges of each of the top, bottom and side panels of the enclosure which engage the front panel when closed in order to provide protection against the ingress of materials, such as discussed above, into the box interior.
Typically, NEMA enclosures and boxes which employ NEMA construction standards include a latch assembly for maintaining the front panel in a closed, locked position. Such latch assemblies generally comprise a latch coupled to opposed latch arms each movable between a retracted and extended position. In order to unlock the enclosure or box and permit opening of the front panel, a key must be inserted into the latch and turned so that the latch arms retract. The front panel is maintained in a closed, locked position by first closing the front panel, inserting the key into the latch and then turning it so that the latch arms are moved to the extended position. This presents a problem for a user who would like to close a box after having removed a tool or other equipment from it, but has his/her hands full and cannot easily close the front panel, and manipulate a key into the latch.
This invention relates to NEMA-style enclosures, and, more particularly, to an improved latch system for such enclosures that automatically locks when the front panel is closed.
This invention is predicated on the concept of providing an enclosure, which meets NEMA standards of construction but with an improved latch assembly which permits closure and locking of the front panel of the enclosure without the use of a key to operate a latch.
In the presently preferred embodiment, the enclosure comprises a top panel, a bottom panel, a back panel and opposed side panels. Each, of the side panels is formed with a front edge comprising a front wall, a back wall and an angled side wall extending between the front and back walls. A front panel is hinged to the bottom wall of the enclosure and movable between an open and closed position. The front panel mounts a latch assembly which includes a latch coupled to opposed latch arms each movable between an extended position and a retracted position. A spring element housed within the latch biases each of the latch arms to the extended position. Each latch arm mounts a tip at its free end which is preferably formed with a leading edge having a taper to engage with the angled side wall on the front edge of each of each side panel.
With the front panel open, the latch arms are biased by the spring in the latch to the extended position such that the tips of each one align with the tapered side wall on the front edge of one of the side panels. In the course of moving the front panel to a closed position, the tip of each latch arm contacts and slides along the tapered side wall of one of the side panels. The angled shape of the side walls causes the latch arms to move toward a retracted position. Once closed, the tips of each latch arm clear the angled side wall of each side panel allowing the spring in the latch to bias the latch arms to an extended position wherein each tip engages the back wall of the front edge of respective side panels. The front panel may be opened by inserting a key within the latch, and turning it, causing the latch arms to retract and clear the back wall of the front edge of the side panels.
An advantage of the improved latch assembly of this invention is that consumers may realize the benefits of using a NEMA type box but with the ability to lock the front panel in place by merely closing it rather than using a key as required in existing NEMA and NEMA-style enclosures, This allows consumers to remove articles from the interior of the enclosure and even with their hands full have the ability to close and lock, the front panel in, place, e.g. using an arm or foot to swing the front panel closed.
The structure, operation and advantages of the presently preferred embodiment of this invention will become further apparent upon consideration of the following description, taken in conjunction with the accompanying drawings, wherein:
Referring to the Figs., an enclosure 10 is illustrated which comprises a top panel 12, a bottom panel 14, a back panel 16, opposed side panels 18, 20 and a front panel 22 which are interconnected to form an interior 24. The front panel 22 is connected by a hinge 26 to the bottom panel 14 and movable between a closed position shown in
As best seen in
The latch 30 is centered on the front panel 22, near the top, and latch arms 32, 34 extend outwardly toward the sides of the front panel 22. The latch arms 32, 34 are supported by guides 44, 46, respectively, which permit movement thereof between an extended position shown in
It should be understood that the size, shape and general configuration of the enclosure 10 shown in the
Referring now to
As noted above, the latch 30 has a spring that normally biases the latch arms 32, 34 away from one another to the extended position shown in
The construction of the latch arms 32, 34, and front edge 60 of each side panel 18, 20, permits the front panel 22 to be moved to a closed and locked position without requiring one to operate the latch 30. It is possible to shut the front panel 22 with an arm or foot, which is especially helpful if one's hands are full of tools or other equipment just removed from the enclosure 10.
While the invention has been described with reference to a preferred embodiment, it should be understood by those skilled in the art that various changes may be made and equivalents substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
