The present invention pertains generally to industrial curtains used as environmental closures for openings through which traffic can still pass. The curtains generally comprise a plurality of usually transparent strips that are suspended contiguously to each other from a hanger or support generally fixed adjacent to a top margin of the opening. Each of the strips usually consists of a length of flexible, generally transparent, material terminating adjacent to a lower margin of the opening. The present invention relates particularly to an improved support from which the industrial strip curtain can be suspended.
Industrial curtains are conventionally employed to provide closures between, for example, separate manufacturing areas within large buildings, warehouses and the like. Goods are often required to be transported from one area of a manufacturing or storage facility to another where one or the other of the areas is heated, air-conditioned or even refrigerated. Sometime other environmental concerns need to be addressed such as dust, fumes, smoke, dirt, or even noise. Where the traffic is only occasional, conventional doors can be employed to close any doorway between the two areas. Where the traffic is considerable, the use of conventional doors gives way to suspended flexible screens or curtains, which inhibit the wholesale transfer of air from one area to the other yet still permit goods-transporting vehicles to pass through with little effort.
These curtains are generally made up of side-by-side elongated plastic strips that hang from a support system mounted to extend across the top of the opening. For safety reasons, it is desirable that the curtain be sufficiently transparent that one operating a transporting vehicle be able to see any hazard or obstruction that might exist on an opposite side of a curtain before proceeding through. Persons on the opposite side of a curtain also desire to be able to see oncoming transport vehicles so appropriate evasive action can be taken. Thus, plastic materials, which were more or less transparent, such as polyvinyl chloride and polyethylene, were adopted as the preferred materials for forming such screens as shown, for example, in U.S. Pat. Nos. 4,095,642, 4,165,778, 4,232,725, and 4,607,678.
Many different support systems have been developed for these strip curtains. One type of support system involves each strip forming the curtain having a loop for receiving a horizontal rod that is mounted adjacent to the top of the opening covered by the curtain by two or more brackets. Examples of this type of support system are disclosed in U.S. Pat. Nos. 4,095,642; 4,384,606; 4,515,202; and 6,213,437. A related type of support system is disclosed in U.S. Pat. Nos. 4,257,471 and 4,776,382 wherein the loops at the top of each strip are formed by separate structural hangers that loop over the horizontal rod and are coupled to each strip forming the curtain. A common disadvantage of such support systems is the tendency for the horizontal rod to sag between supports, which can cause an uneven hang to the strips forming the curtain.
To avoid this disadvantage, some much more complicated hanger schemes have been devised as shown in U.S. Pat. Nos. 4,312,396; 4,335,777; 4,340,106; 4,388,961; 5,146,971; 5,520,237; and 6,050,322 that commonly use extruded profiles or similar structures that are secured adjacent to the top of the opening to be covered by the curtain. The extruded profiles are design to mate with other formed hanger members coupled to the strips forming the curtain. None of these systems have gained wide acceptance, perhaps due to the time involved in assembly of the curtain strips to the hangers and the occasionally awkward engagement between the hangers and the supporting profiles or equivalent structures. Much more simple structures are to be found in U.S. Pat. Nos. 4,165,778; 4,232,725, 4,289,190; and 4,607,678 that disclose a series of threaded fasteners such as a bolts or the like penetrating a series of holes located in the upper ends of each strip. Mating fasteners are engaged on the bolts over the strips to hold the strips in place. The assembly of such structures has been found to be a very time-consuming, repetitive activity, which is often not completed in an entirely satisfactory way, thus leading to later disengagement by the mating fasteners causing the strips to fall away from the support system.
A strip curtain support system that permits fast and easy assembly is disclosed in U.S. Pat. No. 5,127,460. The support comprises a bar having a series of pegs spaced equidistance from each other along the length of the bar. Each peg includes a leg extending substantially perpendicularly outward from the bar. A foot is fixed to each leg so that each foot extends downwardly perpendicular to the stalk and is spaced from the bar. The strips forming the curtain have multiple holes near the top of each strip, which are spaced the same distance from each other as the distance between the pegs. The strips can be suspended from a plurality of the pegs by manipulating the multiple holes upward over the feet and onto the leg portion of each peg. Unfortunately, the downwardly projecting portion of each foot acts, over time, as a lever pressed by the moving curtain that flexes the base of each leg adjacent to the strip upward and downward to such an extent that the support fails by the leg breaking away from the supporting bar.
Accordingly, what is needed is a strong strip curtain support system that allows for fast and easy assembly, yet is sufficiently strong that product failure due to flexing or any other action is unlikely to occur. What is further needed is such a strip curtain support system that permits the curtain strips to be easily changed when the strips become worn or abraded, or for other reasons need moved.
A strip curtain support of the present invention is intended for use in an environmental strip curtain system that is typically employed for at least partially obstructing a passage through a wall. The strip curtain generally has a plurality of flexible transparent strips suspended for the curtain support. Each strip of the curtain includes a plurality of holes of a selected size located adjacent to an upper end of the strip. The strip curtain support of the present invention can include a bar, and mounting elements for mounting the bar to fixed structure adjacent to the passage to be obstructed by the curtain. The mounting elements can be in the form of fasteners adapted to pass through holes or slots in the bar to fasten the bar to the wall or ceiling above the passage. The strip curtain support also includes a plurality of pegs that can be coupled to the bar. Each peg includes an outwardly extending stalk portion that can extend outwardly from the bar. The stalk portion of each peg is generally linear and perpendicular to the bar, however in some circumstances the stalks can be curved so long as the stalks are generally parallel to each other and curve in the same direction and to the same extent. The stalks generally include a curved upper surface. The curved upper surface can form a portion of a cylindrical stalk or tapered stalk.
Each stalk has a proximal end typically connected to the bar and a distal end including a cap spaced by a pre-selected distance from the proximal end of each stalk. The proximal end of each stalk can be fixed to the bar by fastening, staging, welding, casting or molding. The proximal end of each stalk can also be directly fixed to a supporting surface by fastening with either a separate or an integral fastener, in which case the bar can be omitted. Alternatively, the proximal end of each stalk can be received in a slot in bar that can provide for some small variation in alignment of the holes in the strips, or allow for gravitational alignment of the strips even when the bar is not mounted to a supporting surface in a true horizontal manner. When the bar includes a series of slots to receive the proximal ends of the stalks, the slots can include an upper portion that is larger is size than a lowest portion to allow for insertion of the pegs during assembly. In a preferred embodiment each slot includes an angular path between the larger sized portion and the lowest portion so that displacement of the pegs from the slots while a curtain is suspended thereon is rendered nearly impossible.
Each cap, which is located on the distal end of a stalk, is generally symmetric with respect to the stalk to which the cap is fixed. An outermost edge of the cap ranges from ovate to a circle having an outer maximum dimension or diameter greater than the diameter of the holes in the strip to be mounted on the strip curtain support. The diameter of the outermost edge of the cap can be from about 1.2 to about 1.7 times the diameter of the holes in the strip, and is preferably about 1.5 times the diameter of the holes in the strip. The diameter of the stalk generally approximates the diameter of the holes in the strip, although some variation in size will not prevent the combination of the strip curtain and the support from performing satisfactorily.
A distal outer surface of the cap has a shape facilitating the stretching of the holes of each strip to a size sufficient to permit the strip to be forced over the outermost edge of the cap. In a preferred embodiment, the distal outer surface of each cap comprises a substantially conical surface extending from a distal extremity of the cap to the outermost edge of the cap. Alternative embodiments for the distal outer surface of each cap include a mushroom-shape and can include a substantially hemispherical shape extending from a distal extremity of the cap to the outermost edge of the cap.
A proximal surface of the cap extending between the outermost edge of the cap and the stalk to which the cap is fixed is resistant to removal of the strip curtain from the curtain support under normal usage. The proximal surface of the cap can be planar and perpendicular to the stalk, but preferably includes a smooth outer edge to prevent a cutting action on the curtain strips. The proximal surface can also be concave, but is preferably slightly convex. The proximal surface of each cap is spaced from the supporting bar by a distance at least equal to twice the thickness of the strips to be mounted on the curtain support. Preferably, the proximal surface of each cap is spaced from the supporting bar by a distance equal to about five times the thickness of the strips.
One feature of the present invention is an environmental strip curtain system that allows for easy installation of the strips by providing distal surfaces on the peg caps causing a temporary stretching of the material forming the strips immediately surrounding each hole provided at the upper end of the strips. Thus, the curtain strips can be mounted to the pegs on the curtain support by merely pushing the strips onto the pegs with sufficient force to cause the necessary stretching of the material forming the strips.
Another feature of the present invention is an environmental strip curtain system which inhibits any accidental removal of the strips, yet allows for easy replacement of one or more strips by providing caps that are integral with the stalks, rather than screw fasteners that can loosen when subjected to normal vibration and jarring, and by providing proximal surfaces to the caps that do not encourage displacement of the strips past the caps, yet permit replacement of the strips by merely pulling on the strips with sufficient force to again stretch the material forming the strips enough to allow the cap to pass through the holes formed in the strips. By selecting the cap size and hole size appropriately, assuming a known make-up of the materials forming the strips, the removal force can be chosen to be in a range that will realistically prevent any accidental strip removal during normal use.
Additional features and advantages of an environmental strip curtain support system of the present invention will become apparent to those skilled in the art from a consideration of the following discussion of preferred embodiments of the present invention that include the best mode of carrying out the invention as present perceived. The following discussion references the accompanying drawings.
A first embodiment of the curtain holding apparatus 22 of the present invention is shown in
A representative strip 28 is also shown in cross-section in
A second embodiment of a curtain holding apparatus 22 of the present invention is shown in
Yet another embodiment of the curtain holding apparatus 22 of the present invention is shown in
The pegs 46 of
Two further embodiments of a bar 32 suitable for use in a curtain holding apparatus of the present invention are shown in
As shown in
The strips 28 to be used with the curtain holding apparatus 22 of the present invention include a series of holes 52 near the upper margin 54 of each strip as disclosed generally in FIG. 3. The size of the holes 52 is approximately the same as the size of the stalks 48 on which the strips will be suspended. The size of the holes 52 is smaller than the largest dimension of the cap 50, which includes a distal surface 56 that is shaped to facilitate the stretching the material forming the strip 28 in the vicinity of the holes 52 to a size sufficient to permit the strip 28 to be forced over the outermost edge 58 of the caps 50 and onto the stalks 48 where the hole 52 elastically returns to its original size. By contrast, the proximal surface 60 of each of the caps 50 has a more abrupt character that can be essentially perpendicular to the stalk 48, or convex or concave or tapered so that the abrupt change in cross-section inhibits the removal of the strip curtain 26 from the pegs 46 under the conditions of normal use, but still permit forced removal in the event it becomes necessary to replace one or more of the strips 28.
From the foregoing discussion of the various illustrated embodiments of the present invention, it will be appreciated that the various aspects and characteristics of illustrated pegs can be combined with more than one of the illustrated support bars to form a variety of resulting structures all of which follow the spirit of the present invention as previously described, and as hereafter claimed.
This application is related to U.S. provisional patent application Ser. No. 60/361,671 filed Mar. 4, 2002.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US03/05964 | 2/27/2003 | WO | 00 | 10/2/2003 |
Publishing Document | Publishing Date | Country | Kind |
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WO03/075722 | 9/18/2003 | WO | A |
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Number | Date | Country | |
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20040159411 A1 | Aug 2004 | US |
Number | Date | Country | |
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60361671 | Mar 2002 | US |