Patent Application
20050180817
The present invention relates to improved composite supports.
The scope of the present invention is defined solely by the appended claims, and is not affected to any degree by the statements within this summary. Briefly stated, a composite support comprising, a housing, a plurality of fittings, and a composite tube. The composite tube is provided with an outer diameter and includes a first fiber layer including a resin and glass fibers that have been wound around a mandrel, a second fiber layer including glass fibers that have been wound around the first fiber layer, and an outermost fiber layer including glass fibers that is located around the second fiber layer. The housing is at least in part spirally shaped and located around at least a portion of the composite tube. At least one of the fittings includes an aluminum and an anchoring surface. The anchoring surface is located, at least in part, radially around the composite tube, includes a diameter that is smaller than the outer diameter of the composite tube, and secures, at least in part, the fitting to the composite tube, so that, after assembly, the fitting and the composite tube are generally coaxial.
Turning now to the drawings,
The composite tube 12 includes a first end 20 and a second end 22. As used herein, the term “end” is intended broadly to encompass the extreme end as well as portions of the tube 12 adjacent the extreme end. As shown in
The fittings 14 are identical in this example, and an inner portion of one of the fittings 14 is shown in
It is not essential in all embodiments that the tube 12 be straight as shown in
In order to minimize weight and cost of the tube 12, it is preferred to orient the fibers of the tube 12 to carry the torsional and bending loads applied to the tube 12 efficiently. In particular, the tube 12 acts as a torsion bar in both the counterclockwise and the clockwise directions, and it is therefore preferred to include fibers oriented at an angle to the longitudinal axis 26 (
In one example, the tube 12 is formed from many layers of substantially unidirectional fibers. In one example, 32 separate layers are placed around a mandrel. The mandrel is provided with a release agent, such that the mandrel can be removed after the tube is formed. Each of the layers in this example is made up of substantially unidirectional fibers impregnated in a resin binder that is baked in an oven so that the resin is cured. For example, each layer can be approximately 0.006 inch thick with the density of about 0.055 lbs/cubic inch.
In this example, the 32 separate layers are oriented as set out in Table 1. In Table 1, layer 1 is the radially innermost layer, and layer 32 is the radially outermost layer.
It is not essential in all embodiments that the fibers be oriented precisely at 0°, +45° and −45°. In each case, a tolerance band about each direction of ±15°, more preferably ±10°, or most preferably ±5° can be used. Also, it is not essential that all of the fibers be oriented as described above. Preferably, more than 50%, more preferably more than 75% and most preferably more than 95% of the fibers are oriented in the preferred directions described above.
Many materials can be used for the composite tube, such as fiberglass, aramid fiber and other fibers. If desired, an outer layer of aramid fiber can be applied to improve impact resistance. Also, many manufacturing techniques can be used to form the composite tube 12, including the technique described above, bladder molding processes and filament winding processes.
The fittings 14 can be formed of any suitable material. Light metal alloys such as alloys including aluminum, magnesium and titanium are preferred, because they reduce the overall weight of the composite support. The cross-sectional shape of the fittings can be optimized to reduce weight, as by using an oval or an I-beam cross-sectional profile where appropriate. The fittings can be shaped in any desired manner, as for example by casting or forging. When the fittings are made of an aluminum alloy, the alloy can be anodized to avoid galvanic corrosion. Preferably, the fitting is shaped to avoid upset profiles, thereby improving the ease of manufacturing.
The fittings are assembled onto the tube ends using any suitable approach. One approach is to use radial crimping dies to deform or crimp the outermost portion of each fitting against the tube 12 and the anchoring member 32. The anchoring member 32 supports the tube end against radial collapse during the crimping operation. Such radial crimping preferably employs multiple crimping points to reduce or eliminate slipping at the joint. The anchoring member 32 can be integrally formed with the fitting 14 as shown in
The composite support described above provides important advantages. It is unusually light in weight and corrosion resistant as compared to a traditional support.
The foregoing detailed description has described only a few of the many forms that this invention can take. This detailed description is therefore intended by way of illustration. It is only the following claims, including all equivalents that are intended to define the scope of this invention.
This is a continuation of application Ser. No. 10/378,749, filed Mar. 4, 2003, which is a continuation of application Ser. No. 09/846,141, filed Apr. 30, 2001. The disclosure of application Ser. No. 10/378,749 is hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10378749 | Mar 2003 | US |
| Child | 11104312 | Apr 2005 | US |
| Parent | 09846141 | Apr 2001 | US |
| Child | 10378749 | Mar 2003 | US |
