Patent Application
20080185107
The invention relates generally to braces for reinforcing tubes and to tubes reinforced by said braces, and more particularly to a reinforced roller tube for use with extendible awnings of the roll-up type popularly used with recreational vehicles.
Awnings of the roll-up type are well-known in the recreational vehicle field for providing shade and cover from inclement weather, and also for providing additional living space adjacent to the vehicle.
Roll-up awnings are also used in a variety of other settings where temporary cover is required. For example, and without limitation, roll-up awnings are used on hotel and shop fronts, and on trailer homes. One edge of the awning is fixed to the vehicle or building and, in the stored position, the other end is wrapped around a spring-loaded roller tube. The awning can be mounted to the roller tube by means of slideways extending longitudinally within the exterior surface of the roller tube. The roller tube can be pivotably supported by arms extending from the vehicle or building, and can be further supported from the ground by poles, or from the vehicle or building by outriggers. The awning is deployed by unrolling the awning from the roller tube against spring resistance, and supporting and locking the unrolled awning in place. Subsequent stowing of the awning onto the roller tube is facilitated by the aforementioned spring-loading.
In the deployed position, the roller tube must support its own weight, the weight of the awning, and the weight of other attachments such as screens or valances. In addition, the roller tube must resist wind forces acting on the awning, and support any additional weight due to precipitation accumulating on the awning. Because the area of awning and the length of the roller tube can be large (roller tubes of 21 feet or more in length are commonly used), the roller tube must be strongly constructed to minimize bowing or bending in use. A common failure mode of roller tubes is for initial bowing to facilitate further accumulation of precipitation on the awning, leading to complete structural failure of the roller tube.
In the past, a long roller tube would sag between its end supports. To mitigate this problem, additional supports can be used; the roller tube can be constructed from strong materials such as extruded aluminum or steel; and/or stiffening inserts can be positioned within the roller tube.
Examples of each of these approaches can be found, for example, in the following patents. U.S. Pat. No. 4,258,778 discloses a roller tube formed from sheet metal, with optional reinforcement provided by inserts or foamed plastic placed within the roller tube; U.S. Pat. No. 4,508,126 discloses partial length stiffeners for a roller tube; U.S. Pat. No. 5,351,736 discloses a roll-formed roller tube with strengthening ridges formed in its surface; and U.S. Pat. No. 6,598,612 B1 discloses an awning having a mansard shape for minimizing the accumulation of precipitation on the awning and aerodynamically reducing the effect of wind on the awning.
Each of the aforementioned approaches suffers from one or more of the following drawbacks: roll-forming long roller tubes from a sheet metal such as steel has proved to be technically difficult; the stiffeners have a low stiffness to weight ratio; the stiffeners have elaborate shapes that are expensive to make; the stiffeners comprise welds or joints that are expensive to form and which may accumulate stresses and fail in use; or additional supports for the awning are required, which may be cumbersome or obstructive.
Notwithstanding the existence of a variety of awning roller tube strengthening devices in the prior art, there is a continuing need for improved means for reinforcing awning roller tubes that can be simply and inexpensively manufactured from commonly available, light weight materials without the need for welding or jointing, and which minimize the risk of roller tube bending or failure from precipitation or wind. The present invention substantially fulfills these needs. All this and more will become apparent to one of ordinary skill upon reading the disclosure, drawings, and claims appended hereto.
The present invention is directed to a brace for reinforcing a tube, a reinforced tube such as a reinforced roller tube for an awning, and to an awning assembly incorporating said reinforced roller tube. The invention provides an improved brace that is light-weight, resists flexing and twisting, and can be easily and inexpensively manufactured from commonly available sheet materials without the need for welding or jointing.
In a first embodiment, the invention provides a brace for a tube, the brace comprising a pair of mounted, elongate metal strips. Each metal strip comprises a central longitudinal portion, two longitudinal edge portions, and an intermediate longitudinal portion connecting the central portion and each edge portion. The central portions are mounted to each other, for example by rivets. The intermediate portions extend substantially radially from the central portions, and each edge portion forms an angle with the intermediate portion to which it is connected to form a foot for engaging the interior of the tube.
When inserted into a tube, the feet of the brace contact the interior surface of the tube to reinforce the tube. Not to be thereby limited by theory, flexing forces applied to the tube are transferred through one or more of the feet to the mounted central portions of the brace, spreading the force over the contact area of the two central portions, which provides high stiffness. The brace is devoid of joints or welds, which could otherwise accumulate stresses and lead to structural failure.
In a second embodiment, the invention provides a reinforced roller tube for an awning, the roller tube comprising a brace according to the first embodiment disposed within at least a central portion of the roller tube.
In a third embodiment, the invention provides an improved awning assembly, the awning assembly comprising a reinforced roller tube according to the second embodiment, and further comprising an awning having first and second ends, the first end being attachable to a wall or support, the second end being attached to the roller tube, and the awning being rollable around the roller tube.
It is therefore an object of the present invention to provide an improved brace exhibiting a high stiffness to weight ratio for reinforcing a tube, wherein the cross-sectional shape of the tube is not particularly limited, and can include, for example, circular, elliptical, square, hexagonal, or octagonal cross-sections.
It is a further object of the invention to provide a brace for a tube that can be simply and inexpensively manufactured from commonly available, light-weight sheet materials, without the need for welding or jointing.
It is a further object of the invention to provide a reinforced roller tube for use with awnings that minimizes the risk of roller tube bending or failure from the action of precipitation or wind, without unduly adding to the weight of the roller tube.
It is a further object of the invention to provide an improved awning assembly for use on hotels, shop fronts, recreational vehicles, and mobile homes, which resists bending and/or collapse due to the action of wind or accumulation of precipitation on the awning, without unduly adding to the weight, complexity, or cost of the awning assembly.
It is yet a further object of the invention to provide a brace that can be used to reinforce pre-existing tubes, such as existing roller tubes, by subsequent insertion therein of a brace according to the first embodiment.
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
Certain exemplary but non-limiting embodiments of the present invention are now described for illustrative purposes with reference to the attached drawings.
The present invention is directed to a brace for reinforcing a tube, a reinforced tube such as a roller tube for an awning, and to an awning assembly incorporating said reinforced roller tube.
Referring now to
Referring now to
In the prior art brace 206 of
As used herein, the term “joint” refers to an integral tee structure in metal, whether formed by welding, extrusion, molding, or the like, and the term “joint” is therefore distinct to and different from the mounting of two sheets of metal by fasteners.
As shown in
At one or both of a first 306 and second 308 end of the roller tube, optional means 310, 312 are provided for rotationally coupling the roller tube 302 to its support and preferably for providing spring resistance to unrolling of the awning and assistance in its re-rolling. Such means are well-known in the art and typically comprise at least a spring assembly 314, head casing 316, mounts 318 for attaching the roller tube to its support, and a locking means 320 such as a locking pin for holding the awning in an extended configuration.
The central portion of the roller tube 302 comprises one or more braces 304. As used herein, the central portion of the roller tube is any portion of the roller tube excluding the optional means 310, 312 located at a first 306 and second 308 end of the tube. For example, in a preferred embodiment, brace 304 can be disposed within the central ten feet of a fourteen foot roller tube.
The brace 304 comprises a first 322 and a second 324 elongate metal strip mounted to each other. The metal strips can formed from an aluminum or steel sheet, and can optionally further comprise a coating such as galvanized coating. The longitudinal dimension of the strips is selected according to the length of the required brace. The width of the strip is selected to be commensurate with the inner diameter of the roller tube, when the strip is in the configuration of a brace according to the invention, so that the brace can be inserted into the roller tube without binding, and the feet of the brace can contact or be adjacent to the inner surface of the roller tube.
Referring now to
Without being thereby limited by theory, the brace of the present invention is substantially stiff in part because bending moments applied to the tube are distributed over the common surface of the mounted central longitudinal portions 406. Thus, in use, the stress upon the fasteners 408 is low.
The width of central longitudinal portion 406 is selected according to the width required by fasteners 408 and also to permit the intermediate portions 410, 412 to extend substantially radially from central longitudinal portions 406 towards the inner surface of the tube. In preferred embodiments, the width of central longitudinal portion 406 is approximately 20% of the inner diameter of the tube.
The longitudinal outer edge 414 of each intermediate portion 410, 412 forms an angle with the intermediate portion to which it is contiguous to form a foot for contacting the inner surface of the tube. The feet can be oriented in a clockwise or anti-clockwise direction with respect to a transverse section of the brace, or a single brace can comprise a combination of clockwise and anti-clockwise-oriented feet. The location of the feet is selected to engage the inner wall of the tube, whereby the brace can be freely inserted into the tube without binding, and bending moments applied to the tube are transferred to the brace via the feet. As used herein, the term “engage” encompasses feet that are proximal to or in contact with the inner surface of the tube. It is not required that the feet be mounted or connected to the inner surface of the tube.
Referring now to
The brace of the present invention is not limited to tubes of circular cross-section. Referring now to
In use, a brace according to the present invention is inserted into at least a portion of a tube or roller tube to achieve reinforcement. For example, a brace can be inserted into the central one-third of a tube, or a plurality of shorter braces can be used, or the full length of a tube excluding end fittings, if any, can be reinforced.
The device of the present invention provides a number of advantages over the prior art. The brace exhibits a high stiffness to weight ratio for reinforcing tube of essentially any desired cross-section. The brace can be simply and inexpensively manufactured from commonly available, light-weight sheet materials, such as aluminum or steel sheet, without the need for welding or jointing. The brace can be used in a wide variety of applications, including its use to reinforce the roller tube of an awning wherein it minimizes the risk of roller tube bending or failure from the action of precipitation or wind without unduly adding to the weight of the roller tube. Further, the brace of the present invention is readily adaptable for retro-fitting for reinforcement of pre-existing tubes.
Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible and can be envisaged within the scope and spirit of the present invention. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.
Now that the invention has been described:
