TORSION SPRING POWERED DOOR

Abstract: An access door (10) has a frame (12, 14) formed with longitudinally extending channels (24) which receive a closure element (26) for sliding therealong. A torsion spring (38) secured to the frame (14) and to the closure element (26) maintains the closure element (26) in an open or closed position.

Description: Technical Field This invention relates to access doors located on enclosures and, more particularly, to an access door powered by a torsion spring and used on cabinets. The door of the type described herein is particularly suited for closing an access opening in a cabinet storing electrical components or controls which may have to be inspected, operated and replaced from time to time. The door is easily installed and is easily movable from its closed to its fully or partially open positions to provide an easy access to the interior of the cabinet. Background of The Invention Access doors used in similar cabinets before the present invention are expensive in that they require mechanical latches or stops to keep them in closed or open positions and additionally, the doors are usually hung on hinges, which, when exposed to elements, tend to become rusty and inoperative, or open in such a way as to be a hinderance by interfering with adjacent objects. From GB-A-1 389 520 there is further known a cabinet in which a cutout is covered by a plastics cover plate which is slidingly supported in two channels arranged in the cabinet wall. Disclosure of the Invention In accordance with the present invention as claimed, the access door is closed or opened without the use of any mechanical latches or keepers. The door, in a form of a slidable closure element, does not require any hinges as it slides within a frame. A wire torsion spring, such as a music wire, when twisted in one direction, keeps the closure element away from the access opening, and when twisted in another direction, closes the opening by positioning the element over the opening. Generally, the door of the present invention includes a frame formed with a pair of spaced columns which define opposed longitudinally extending channels. The channels receive the edges of a closure element, or slide. A wire torsion spring,, is connected to the closure element and to the frame so that when the closure element is moved in the channels by exerting a force against it by hand, the spring, through its twisting motion, operates against the closure holding the same in a desired closed, open or partially open position. The Drawings FIG. 1 is a perspective view of a cabinet embodying the present invention; FIG. 2 is an exploded view of the elements comprising the door of the present invention; FIG. 3 is a detailed view of the connection between the spring and the frame; FIG. 4 is a partial sectional view from the interior of the cabinet taken generally along the line 4-4 of FIG. 1 showing the closure element in the closed position; FIG. 5 is a partial sectional view from the interior of the cabinet taken generally along the line 4-4 of FIG. 1 showing the closure element in the open position; FIG. 6 is a sectional view taken generally along the line 6-6 of FIG. 4. Detailed Description Referring now to FIG. 1, there is shown a cabinet, generally designated C, formed with an access door assembly, generally designated 10, comprising the present invention. The major elements of this invention are best seen in FIG. 2 and include a pair of frame portions 12 and 14 formed with cross-bars 13 and 15, respectively. The frame portion 12 has a plurality of pins 16 extending therefrom, while the frame portion 14 has a plurality of apertures 18 formed thereon for releasably receiving the pins 16 so as to secure the two frame portions to one another without separate fasteners and to form a door frame. The frame portion 14 has recesses 17 along its outer edge for mounting the frame on the cabinet C. As shown in FIGS. 1, 4 and 5, the front panel of cabinet C has an opening 11 to provide access to the interior of the cabinet. The frame portion 12 has a lip 19 extending from the surface opposite the surface having pins 16, the lip 19 having dimensions allowing it to pass through opening 11 with the minimum amount of clearance. A pair of retainers 46 are fastened on opposite sides of the opening 11 to the back side of the front panel. The retainers 46 are spaced apart so as to allow the frame to pass between them and each has flexible fingers 48 extending from its sides towards the opening 11. The fingers 48 are adapted to releasably mate with recesses 17 of the frame portion 14. To mount the frame in the cabinet, the lip 19 is inserted through the opening 11 from the back of the panel whereby frame portion 12 cams the flexible fingers 48 until the lip 19 is securely seated in the opening 11 at which time fingers 48 are able to snap back and enter recesses 17 thereby applying pressure to the frame to keep the lip 19 in the opening and the frame pressed against the back of the cabinet panel. The frame portions 12 and 14 have longitudinally extending channels forming grooves 20 and 22, respectively, which, when the two portions brackets are secured to each other, form longitudinally extending channels 24. A slide, or closure element 26 may be manufactured from transparent material, such as plastic or glass, to permit inspection of contents of the cabinet C without opening of the closure element 26. The closure element 26 has its edges 28 and 30 received in channels 24 for slidable mounting of the element in the frame and for movement along said channels. One end of the closure element 26 has a hand bar 32 formed thereon for exerting a force and moving the element 26 along the channels 24 into closed or open positions. The opposite end of the closure element has a retainer 34 wherein is mounted a central portion 36 of a wire torsion spring 38. The spring 38 has its opposite ends 40, which are formed in a substantially U-shaped configuration, inserted in slots 42 formed in the frame portion 14 and removably retained in wire tip receiving recesses 44 also formed in frame portion 14, as best shown in FIG. 3 FIG. 4 shows the element 26 in the closed position, preventing access into cabinet C via opening 11, the element 26 being held in place by the torsion spring 38. To provide access, the element 26 is moved by hand pressure exerted on the bar 32 in the direction shown by arrow F, whereby the spring 38 is twisted in the direction of movement with its central portion 36 moving past the line extending between the slots 42 on both sides of the frame portion 14. The element 26 may be moved to uncover the opening 11 to its maximum and be locked in the open position by complete inversion of the spring 38, as shown in FIG. 5. The closure element 26 may be stopped at a half-way position providing a partial opening when the spring portion 36 is moved into an alignment with its end portions 40 so that the force exerted by spring 38 forcing the element 26 into the closing direction is equal to that forcing it into the opening direction, thus, retaining the element 26 in a partially open position.

Claims: An access door assembly (10) for mounting in a cabinet (C),, comprising: a frame (12, 14) having a pair of spaced, parallel columns defining opposed parallel channels (24); a cross-bar (13, 15) joining said channels (20, 22); a closure element (26) slidably received in said channels (24) for movement therein between open and closed positions; a spring means (38) connecting said element (26) to said frame (12, 14) and being operable against said element (26), when it is in either open or closed position, to maintain said element (26) in a preselected position. An access door assembly as defined in claim 1, wherein said spring means (38) comprises a torsion spring. An access door assembly as defined in claim 1, wherein said spring means (38) comprises a wire-type torsion spring. An access door assembly as defined in claim 1 further comprising means (17, 46, 48) for mounting said assembly (10) in the cabinet (C). An access door assembly as defined in claim 4, wherein said mounting means comprises: a pair of retainers (46) in the cabinet (C), each retainer (46) having at least two flexible fingers (48) extending therefrom, and; each of said columns (14) having at least two recesses (17), each recess (17) adapted to receive of one said fingers (48). An access door assembly as defined in any of claims 1-5, wherein said channels (24) extend longitudinally to said columns (12, 14). An access door assembly as defined in any of claims 1-6, wherein said frame is formed by a pair of parallel frame portions (12, 14) removably connected to each other. An access door assembly as defined in claim 7, wherein a channel (20, 22) is formed in at least one of said frame portions (12, 14). An access door assembly as defined in any of claims 1-8, wherein said cabinet (C) has a substantially rectangular opening (11), wherein said channels (24) and cross-bars (13, 15) defining an opening which substantially matches shape and size of the opening (11) in the cabinet (C); and wherein said closure element (26) is of a size and shape to fit said opening in the frame (12, 14) having two of its edges (28, 30) slidably mounted in said channels (24) for movement of the closure element (26) therein between open and closed positions.

Inventors: BISCHOF, ALFRED, RUMPS, NORBERT A., JR.
Applicants: AMERICAN TELEPHONE AND TELEGRAPH COMPANY
Application year: 1988
Main classification: H05K5
IPC codes: A47B95, E05F1, H05K5