GB1558532A

GB1558532A - Acces door

Info

Publication number: GB1558532A
Application number: GB3653677A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-09-02
Filing date: 1977-09-01
Publication date: 1980-01-03

Description

(54) ACCESS DOOR (71) 1, LEONARD PHILLIPS, a citizen of the United States of America, of 6001 Bayou Grande Road, St. Petersburg, County of Pinellas, Florida, United States of America, do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to an access door primarily designed to provide an insulated entrance to heating, ventilating and air conditioning ducts.

Presently there exist numerous devices, generally doors, designed to provide an entrance to an area. When doors are utilized, they generally are the conventional fixed hinged door although more elaborate swinging or removable arrangements may be used. Doors of this type provide access to areas such as electrical panel boxes, wall service outlets and plumbing networks. Typical access door assemblies are described in United States Patent Specifications Nos. 3,537,212; 2,766,856 and 1,921,051. For certain needs, such as air conditioning ducts, removable doors have been devised. They usually comprise a frame securely fastened to the surrounding wall of the duct. A flat sheet metal pan easily disconnectable from the frame enables easy access. Since the frame must be securely fastened to the wall, its installation is quite expensive.For sheet metal work, expensive installation is undesirable.

The prior art also discloses closures designed to removably seal apertures such as windows. For example, United States Patent Specification No. 2,772,447 discloses a panel assembly connected to a wall by a fastening means. The fastening means comprises a plurality of beams straddling the aperture on the opposite side of the said wall. Such closure means do not comprise an easy access door. They require complete removal of the closure means and for such reason, are too cumbersome. Also such closure means do not easily provide acoustical or thermal insulation properties nor are they generally aesthetically pleasing.

Since mechanisms such as fire dampers contained within ducts periodically require inspection and servicing, it is most desirous for the access to insulatingly cover the opening and then, when need be, allow convenient access to the mechanism.

An aim of this invention is to provide an improved access door particularly suitable for closing an access aperture in a duct. With this aim in view, the invention is desirably directed to an access door for closing an access aperture in a panel, for example a panel forming part of a duct, the door comprising two door pans hingedly mounted on a pan carrier which is so constructed that in use of the door the carrier can be detachably mounted on a panel edge region bounding one side of the access aperture, with the pans disposed one on each side of the panel, whereby the pans can be swung on their hinges to respective closed positions to abut the panel around the access aperture to close the same, releasable securing means being provided for releasably securing the pans together to hold them in their closed positions against the panel.

However, the invention also extends to an access door comprising a two pan structure closing an access aperture in a panel, for example a panel forming part of a duct, the two pans of the structure being hingedly mounted on a pan carrier and lying in respective closed positions facing each other with the pans overlapping edge regions of the panel around the access aperture, the pans being releasably secured together by releasable securing means which holds the pans against the panel.

Several embodiments of an access door according to the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a front view of a first embodiment of the invention showing an access door comprising two pans closing an aperture in a panel of a duct, one of the pans being shown partly broken away; Figure 2 is a sectional view taken on the line Il-Il in Figure 1; Figure 3 is a view in section showing one part of a pan carrier of the door of Figures 1 and 2, the carrier being shown above a duct panel side edge; Figure 4 is a perspective exploded view of the pan carrier part of Figure 3; Figure 5 is a perspective view of an access door very similar to the door of Figures 14, with the two pans being shown hinged away from each other;; Figure 6 is a view similar to Figure 3, showing one part of a modified pan carrier riveted to a duct panel; Figure 7 is a front view of the pan carrier part of Figure 6, and Figure 8 is a view similar to Figure 3 showing another form of pan carrier.

The access door 1 shown in Figures 14 comprises two pans 4 and 5 hinged to a pan carrier 2. The pan carrier 2 comprises two saddle members 17 of inverted U-shape disposed at opposite ends of adjacent bottom edges of the pans. Each saddle member 17 is formed with a pair of outwardly directed ears 18, and tabs 20 integral with the pans 4 and 5 are pivotally secured to the ears by pins 21. The pans 4 and 5 can be pivoted on the pan carrier 2 between open positions (Figures 3, 5 and 8) and closed positions (Figures 1, 2, 4, 6 and 7).

The pans comprise metal or plastics material rectangular dishes 37 filled with a material 39 which is thermally and/or acoustically insulating.

A preferred insulating material is fibreglass.

Between the rim of metal dish 37 and the insulating material 39 there is disposed a sealing gasket 36. The gasket 36 presents a rather narrow edge for sealing against a duct panel in a manner described below, and a wider sealing gasket may be preferable, such as the expanded neoprene gasket 38 shown in the embodiment of Figure 5.

Referring again to the embodiment of Figures 1-4, the pan 4 has a retaining catch 6 mounted centrally on its side edge remote from the pan carrier 2. Catch 6 comprises a spring strip having a projection 6a.

As best seen in Figure 2, the pans 4 and 5 can be releasably secured together in their closed positions by securing means comprising a stud 34 fast on the dish 37 of pan 4 and a locking knob 40. The stud passes through an opening 41 in pan 5 when the pans are closed, and the stud end which projects beyond pan 5 is screw threaded to receive the nylon locking knob 40.

The method of use of the access door will now be described. A panel 3, (Figures 2 to 4) for example a thin sheet metal panel of a heating or ventilation duct, is formed (by cutting with metal shears) with an access aperture slightly smaller than the rectangular pans 4 and 5. The pan 4 of access door 1 (which door can be completely fabricated at a factory) is then diagonally inserted in its open position with pans separated into the access aperture, and the door is then manouvered so that the pans lie one on each side of the panel 3, with the pan 4 inside the duct and the pan 5 outside. One saddle member 17 is then placed over the lower edge 3a (Figure 3) of the panel 3 which bounds the access aperture, and the door is then slid along and downwards until the other saddle member 17 also straddles panel edge 3.The inside pan 4 is then pulled upwardly to its closed position by manually pulling the stud 34 of the securing means. The spring catch 6 then snaps into place in engagement with an upper edge 3b of the panel 3, and the projection 6a of catch 6 engages the front face of the panel 3 to stop the pan 4 from falling back into the duct. The outer pan 5 is then hinged up into its closed position until the stud 34 passes through the opening 41 in pan 5. The knob 40 is then screwed tightly onto stud 34 to hold the two pans 4 and 5 together and to thus urge the sealing gasket 36 into sealing contact with the panel.

The access door shown in Figure 5 is very similar to the door of Figures 14. The door of Figure 5 has, however, a wider gasket 38 as mentioned above, and the catch 6 is replaced by a bar 42. The bar 42 has an opening (not shown) in it, and the stud 34 passes through the opening until a shoulder (not visible in Figure 5, but shown at 43 in Figure 2) abuts the bar 42. A nut 44 is screwed onto the threaded end of the stud 34 to hold the bar 42 against shoulder 43. The door of Figure 5 is used in the same way as the door of Figures 14, except that when the inside pan 4 is pulled up against panel 3 it is held in place by bar 42 instead of catch 6. When the pan 4 is pulled up the bar 42 will be in its position illustrated.The bar will then be pivoted on stud 34 (with nut 44 loose) until an end 42a of bar 42 overlies upper panel edge 3b (Figure 2 The nut 44 will then be tightened to hold pan 4 in place by clamping panel edge 3b between pan 4 and bar end 42a. The outside pan 5 will be secured in its closed position as described above.

Figures 6 and 7 show a pan carrier comprised by two pairs of angle plates 25 (only one pair of which is shown in Figure 6) which are riveted to the panel edge 3a by rivets 26. Hinge leaves 9 are riveted to the pans by rivets 13 and are pivoted to the angle plates 25 at 14.

The pan carrier shown in Figure 8 comprises a pair of saddle members 12 (only one of which is shown). The saddle members 12 are detachably mounted on panel edge 3a like the saddle members 17 of the embodiment of Figures 1-4, but the ears 18 at the ends of saddle members 17 are replaced on saddle members 12 by angle members 8 which extend partly along panel edge 3a. The angle members 8 are secured to the pans 4 and 5 by means similar to those shown in Figures 6 and 7.

In a modification (not shown), the means for releasably securing the pans together comprises an internally screw threaded boss fast on one pan and a bolt which is adapted to be or which is screwed into the boss, the other pan having an opening for the bolt to pass through.

The two-pan structure of all embodiments will maintain sealing contact with panel 3 even under high air pressure in the duct. In conventional door assemblies, high pressure present in high velocity ducts tends to push the door away from the edge of the access aperture to break the seal and cause it to leak. In contrast, as pressure increases, the inner pan 4 of the twopan structure increasingly creates a better seal.

Another advantage of the two-pan structure is that it provides additional support to the thin, weak and easily deformable duct material normally used. The customary large amount of stress encountered at the access aperture is thereby counteracted. Even very thin ducts can be used without concern for ripping or deforming the edge of the access aperture.

Another advantage of the two-pan structure is its ability to correct deformations at the edge of the access aperture that usually occur in cutting the aperture. Usually, apertures in ducts are created by simply cutting the desired configuration with a pair of sheet metal shears.

Shears deform the edges into a wavy surface.

The two-pan structure, upon tightening of knob 40, acts to correct these deformations.

An advantage of the embodiments of Figures 1 to 5 and 8 is that the U-shaped saddles hingedly connected to each pan permit the door to be entirely factory fabricated, whereas the embodiment of Figures 6 and 7 requires the use of a riveting tool. With a detachable pan carrier, installation is very easy. In duct work, time saving is extremely valuable.

It will be understood that an access door according to the invention can be used not only with heating, ventilating and air conditioning ducts, but also with other ducts or arrangements where panels have access apertures.

WHAT I CLAIM IS: 1. An access door comprising a two pan structure closing an access aperture in a panel, for example a panel forming part of a duct, the two pans of the structure being hingedly mounted on a pan carrier and lying in respective closed positions facing each other with the pans overlapping edge regions of the panel around the access aperture, the pans being releasably secured together by releasable securing means which holds the pans against the panel.

2. An access door according to claim 1, in which the pan carrier is detachably mounted on a panel edge region bounding one side of the access aperture.

3. An access door for closing an access aperture in a panel, for example a panel forming part of a duct, the door comprising two door pans hingedly mounted on a pan carrier which is so constructed that in use of the door the carrier can be detachably mounted on a panel edge region bounding one side of the access aperture, with the pans disposed one on each side of the panel, whereby the pans can be swung on their hinges to respective closed positions to abut the panel around the access aperture to close the same, releasable securing means being provided for releasably securing the pans together to hold them in their closed positions against the panel.

4. An access door according to claim 2 or claim 3, in which the pan carrier comprises at least one carrier member having a U-shaped part which is adapted to straddle, or which straddles the said panel edge region on which the door is to be, or is, mounted.

5. An access door according to claim 4, in which the U-shaped part of the carrier member comprises a pair of limbs the end regions of which are directed outwardly away from one another and carry hinges connected to respective pans.

6. An access door according to claim 4, in which the U-shaped part of the carrier member has connected to it a pair of ears to each of which is hingedly connected a respective pan.

7. An access door according to claim 5 or claim 6, in which the pan carrier comprises two said carrier members spaced apart along side edges of each pan.

8. An access door according to any one of claims 2 to 7, in which one of the pans is provided with a catch which in use of the door engages an edge of the panel defining the access aperture.

9. An access door according to claim 8, in which the catch is a spring member disposed at a side edge region of its associated pan which is remote from the pan carrier.

10. An access door according to claim 8 or claim 9, in which the pan which carries the catch also carries a fixedly mounted part of the said releasable securing means.

11. An access door according to any one of claims 2 to 10, in which the releasable securing means comprises a screw threaded stud fast on one pan, and a screw threaded knob which is adapted to be, or is, screwed onto the stud, the other pan having an opening for the end of the stud to pass through.

12. An access door according to any one of claims 2 to 7, in which the releasable securing means includes a stud fast on one pan, and in which a bar is pivotally mounted on the stud, such bar being of a length to overlie an edge of a pan remote from the pan carrier, means being provided to lock the bar against a shoulder on the stud to trap a panel edge between an end of the bar remote from the stud and the pan on which the stud is mounted.

13. An access door according to any one of claims 2 to 10, in which the means for releasably securing the pans together comprises an internally screw threaded boss fast on one pan, and a bolt which is adapted to be or which is screwed into the boss, the other pan having an opening

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. In a modification (not shown), the means for releasably securing the pans together comprises an internally screw threaded boss fast on one pan and a bolt which is adapted to be or which is screwed into the boss, the other pan having an opening for the bolt to pass through. The two-pan structure of all embodiments will maintain sealing contact with panel 3 even under high air pressure in the duct. In conventional door assemblies, high pressure present in high velocity ducts tends to push the door away from the edge of the access aperture to break the seal and cause it to leak. In contrast, as pressure increases, the inner pan 4 of the twopan structure increasingly creates a better seal. Another advantage of the two-pan structure is that it provides additional support to the thin, weak and easily deformable duct material normally used. The customary large amount of stress encountered at the access aperture is thereby counteracted. Even very thin ducts can be used without concern for ripping or deforming the edge of the access aperture. Another advantage of the two-pan structure is its ability to correct deformations at the edge of the access aperture that usually occur in cutting the aperture. Usually, apertures in ducts are created by simply cutting the desired configuration with a pair of sheet metal shears. Shears deform the edges into a wavy surface. The two-pan structure, upon tightening of knob 40, acts to correct these deformations. An advantage of the embodiments of Figures 1 to 5 and 8 is that the U-shaped saddles hingedly connected to each pan permit the door to be entirely factory fabricated, whereas the embodiment of Figures 6 and 7 requires the use of a riveting tool. With a detachable pan carrier, installation is very easy. In duct work, time saving is extremely valuable. It will be understood that an access door according to the invention can be used not only with heating, ventilating and air conditioning ducts, but also with other ducts or arrangements where panels have access apertures. WHAT I CLAIM IS:

1. An access door comprising a two pan structure closing an access aperture in a panel, for example a panel forming part of a duct, the two pans of the structure being hingedly mounted on a pan carrier and lying in respective closed positions facing each other with the pans overlapping edge regions of the panel around the access aperture, the pans being releasably secured together by releasable securing means which holds the pans against the panel.

for the bolt to pass through.

14. An access door according to any one of the preceding claims, in which each pan has extending around its periphery an elastomeric sealing gasket for engaging, or which engages, the panel edge region bounding the access aperture.

15. An access door according to any preceding claim, in which each pan comprises material having good insulating properties providing insulation against the passage of heat and/or sound.

16. An access door according to claim 1, or claims 14 and 15 when appendant to claim 1, in which the pan carrier is fixedly secured to the panel adjacent an edge of the access aperture.

17. An access door substantially as described herein with reference to Figures 1-3, Figures 4 and 5, Figures 6 and 7, or Figure 8 of the accompanying drawings.