Patent Application
20240263514
The present invention relates to the field of hurricane screen fabrics and, more particularly, to a spring loaded retention device for securing screen fabrics used in high wind environments.
Property protection is of paramount importance to property owners. Damage from high winds is preventable by covering openings, patios, and the like structures that are susceptible to high winds. For instance, hurricane force winds can quickly breach an opening of a structure, resulting in extensive damage. Windows and doors, if pierced open by flying debris, place the entire structure at risk. Once winds are allowed inside a property, debris and wind changes the air pressure quickly and intensely. In an instance, the change in air pressure with wind accompaniment can lift the roof off the property. Covered patios are but another example of property areas that can be damaged if wind is able to get below the roof.
Roll up hurricane shutters are well known in their ability to prevent wind breaching. Roll up shutters provide excellent frangible area coverage and, once installed, can be deployed by simply drawing interconnected panels from a storage housing. The interconnected panels are difficult to breech, providing excellent security coverage that can be deployed by simply pulling the shutters from a shutter housing. In many instances, the use of screen fabrics have become a desirable alternative, as the screen fabric is less weight and easier to store. In many instances, the screen fabrics can be stored on site using a retractable system wherein screen fabric edges are fed through channels to provide securement without additional fasteners. For high winds, a screen fabric having a continuous edge attachment is more secure than a screen fabric having spaced apart fasteners. While screen fabrics allow some wind to pass, if rain is present, the water acts as a wind barrier wherein no wind can pass through the screen fabric. When this occurs, the screen fabric acts as a sail and subjects the fasteners to the highest possible pressures.
In certain instances, hurricane screen fabrics have become the choice of protection. For instance, when the area to be protected is large, use of a screen fabric may be the only practical option. A screen fabric can be rolled into a storage housing that is smaller in size than a shutter storage housing having a similar length. Hurricane screen fabrics are the preferred articles for sunlight shading and insect blocking. A typical hurricane screen fabric installation consists of a storage housing containing a roll of hurricane screen fabric. In a preferred embodiment, the roll can be rotated for deployment of the screen fabric or retraction of the screen fabric. A base slat is attached to the distal end of the screen fabric which is drawn to the floor, window or door sill and secured thereto using a track. A common problem with all known hurricane screen fabrics is that the base slat lifts off the floor in windy conditions. Reports indicate that the base slats may lift off the floor by several inches or completely pull out of the track in winds of only 30-40 mph.
Hurricane screen fabric is formed from a fabric typically woven using two materials, a polymer in the horizontal direction and aramid (Kevlar) in the vertical direction. This causes the fabric to stretch and billow in the polymer (Horizontal) direction and not stretch or billow in the aramid (Vertical) direction. In this configuration, when wind pressure is applied, the fabric is held firmly by the housing along the top and the tracks on either side. The screen fabric is essentially a wind block at higher wind speeds, placing the most pressure on the base slat. As a result, the fabric begins to lift the base slat off the floor. For instance, a 24 foot screen fabric unit will lift the base slat approximately two feet off the floor.
Various prior art references address ways of securing a screen fabric. U.S. Patent Publication 2006/0137836 discloses a sealing curtain assembly having a pair of tracks attached to opposite sides of an opening. Each track includes a spring system which urges the tracks outwardly to maintain the curtain taut. The spring system employs a connecting member, preferably a bolt, which allows the track edges to separate from a frame member. In one embodiment, a compression spring and washer are located between the head of each connecting member and track. A problem with the use of spring-loaded connecting members is that the spacing between each member provides an area for the screen fabric to bind between connecting members.
U.S. Pat. No. 8,607,841 discloses a screen fabric device having inner rails that are embedded inside fixed guide rails which guide protrusions at side edges of a screen fabric which is wound via a take-up shaft. Each inner rail has a guide groove in which the guide protrusion is inserted, and inward flanges are provided at an opening of the guide groove. Rail members have outer side protrusions and inner side protrusions of different heights at both side edges of a rail base plate. The higher outer side protrusions are confronting. A micro gap extends between the lower inner side protrusions into the guide groove such that the micro gap is opposed to a guide gap formed between the opposed inward flanges. The guide protrusion is slid and guided in a come-off preventing state by the inner side protrusion, so that an extremely thin fastener element can be used as the guide protrusion. While spacing of the screen fabric edge allows for movement, the use of an inner guide rail that is spaced apart allows for screen fabric wrinkles.
Applicant's U.S. patent Ser. No. 11/326,395, entitled Retractable Screen with Horizontal Tensioning Track and Vertical Biasing Member, discloses a retractable screen fabric device for a framed opening employing a frame track fastened to each side support of the framed opening, forming a compartment. A guide rail is positioned within each compartment of each frame track extending the longitudinal length of each frame track. A decompression gasket is positioned between the frame track and the guide rail.
What is needed in the art is a spring loaded screen fabric retention device to avoid lifting of the base slat.
Disclosed is a spring loaded screen fabric retention device in the form of a motor and spring combination for a hurricane screen fabric. The combination overcomes the change in torque so as to allow the motor to operate if there is a change in the initial torque interrupting motor operation. The problem to overcome is when the motor detects a change in the initial torque and will not operate.
An objective of the invention is to prevent the base slat from lifting to high wind loads.
Another objective of the invention is to disclose the use of an electric motor with a spring to retain a specific amount of torque at all times, equal to or greater than the total weight of a screen fabric; the spring having the capacity to add torque when it is needed.
Yet another objective of the invention is to disclose a spring loaded retention device for securing screen fabrics wherein a drive motor will not detect a change in torque, allowing the motor to operate normally. When high winds are encountered, the spring loaded retention device will add torque and allow additional fabric to deploy without causing the base slat to lift. After the winds subside, the spring will return to its retained state.
Yet still another objective of the invention is to teach the use of a torsion member to place a consistent tension on a motor and allow a flexible screen fabric an amount of space to expand.
Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with any accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. Any drawings contained herein constitute a part of this specification, include exemplary embodiments of the present invention, and illustrate various objects and features thereof.
Detailed embodiments of the instant invention are disclosed herein, however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific functional and structural details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representation basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.
Referring to
The preferred flexible screen fabric 30 is screen fabric material constructed of polymer threads running between the first side edge 22 and the second side edge 26 in a horizontal plane. The first and second side edges 22, 26 would include a slide mechanism which resembles a zipper element, which is constructed and arranged to slide along the elongated receptacles 20, 21; the zipper element providing a thickness to resist pulling away from the elongated receptacles 20, 21. A plurality of breaks in the zipper element allow the screen fabric material to be tightly wound for storage purposes. The preferred flexible screen fabric 30 is made of aramid (Kevlar) threads placed in a vertical position and interwoven with the polymer threads extending from the upper edge 24 to the bottom edge 28. The bottom edge 28 is attached to an aluminum base slat 32. An end retention element 34 is secured to the base slat with fasteners 36 along the first side edge 22, and end retention element 38 is secured to the base slat 32 along the second side edge 26 with fasteners 39.
A housing 40 is secured to the upper framing member 102. The housing 40 is formed of a first end cap 42 secured to a top 44 of the first rail 12 and a second end cap 46 secured to a top 48 of the second rail 16. The housing 40 is formed by an upper panel 50 having a back side wall 52 and a lower panel 54 having a bottom side wall 56. The panels 50, 54 are secured together using fasteners 58 to form a rectangular storage box for securement of a tubular motor 60 which is electrically coupled 62 to a power source. The tubular motor 60 has a proximal end 64 coupled to a second bearing bracket 66 which is fastened to the second end cap 46; the second end cap 46 having an edge 52 for securing the second end of the housing 40 to the top 48 of the second rail 16. Similarly, the distal end 68 of the tubular motor 60 is coupled to a first bearing bracket 67 fastened to the first end cap 42, securing the tubular motor 60 to the housing 40 and first rail 12. The upper edge 24 of the screen fabric is attached to an axle 70. The motor 60 connects to the idler end of a small, but stout, spring 72. The torque transfers through the spring assembly 72 and drives a tube 80. During normal motor operations, the spring 72 remains stationary and the motor 60 moves the screen fabric up and down. When the unit is in the down position and pressures are applied, the motor 60 remains stationary and the spring 72 rotates and deploys additional screen fabric. As a result, the base slat 32 remains on the floor and does not lift up.
Referring to
Referring to
Calculation of the total curtain weight is necessary to size the total spring torque. In the preferred embodiment, the total spring torque is 150% of the curtain weight. Total curtain weight is calculated by adding the fabric weight, base slat weight, and additional friction weight. Once the total curtain weight is calculated the total spring torque can be estimated. Fabric weight is calculated by multiplying the width (ft) of the screen against the height (ft) of the screen. The total fabric in pounds (lbs) is calculated by multiplying the total area in square feet against the fabric in pounds per square foot to obtain the total fabric weight (lbs). The base slat weight is obtained by multiplying the unit width (ft) against the base slat weight (lbs). Additional friction weight is calculated by multiplying the unit height (ft) by the additional fiction per linear foot to obtain the total friction in pounds.
Total spring torque is calculated by taking the total curtain weight in pounds which would equal 100% of the confined spring torque. An additional spring torque of 50% is added to the total curtain weight. The preferred total spring torque range is between 100% to 150% of the curtain weight.
The term “coupled” is defined as connected, although not necessarily directly, and not necessarily mechanically. The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more” or “at least one.” The term “about” means, in general, the stated value plus or minus 5%. The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternative are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and/or.”
The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”) and “contain” (and any form of contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, a method or device that “comprises,” “has,” “includes” or “contains” one or more steps or elements, possesses those one or more steps or elements, but is not limited to possessing only those one or more elements. Likewise, a step of a method or an element of a device that “comprises,” “has,” “includes” or “contains” one or more features, possesses those one or more features, but is not limited to possessing only those one or more features. Furthermore, a device or structure that is configured in a certain way is configured in at least that way, but may also be configured in ways that are not listed.
All patents and publications mentioned in this specification are indicative of the levels of those skilled in the art to which the invention pertains. It is to be understood that while a certain form of the invention is illustrated, it is not to be limited to the specific form or arrangement herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown and described in the specification and any drawings/figures included herein.
One skilled in the art will readily appreciate that the present invention is well adapted to carry out the objectives and obtain the ends and advantages mentioned, as well as those inherent therein. The embodiments, methods, procedures and techniques described herein are presently representative of the preferred embodiments, are intended to be exemplary, and are not intended as limitations on the scope. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention and are defined by the scope of the appended claims. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in the art are intended to be within the scope of the following claims.
