Patent Application
20080092450
The following detailed description, given by way of example and not intended to limit the invention solely thereto, will best be appreciated in conjunction with the accompanying drawings, wherein like reference numerals denote like elements and parts, in which:
a)-1(c) depict a prior retractable sliding or rolling door for trailer trucks.
The present invention is now discussed in more detail referring to the drawings that accompany the present application. In the accompanying drawing, like and/or corresponding elements are referred to by like reference numbers.
Referring back to
Most preferably, at least the exterior roof guide surface 15 facing outward from the trailer's longitudinal centerline includes the wear resistance coating. In another embodiment, the upper roof guide surface 20 is coating with a wear resistant coating, preferably in combination with a wear resistance coated exterior roof guide surface 15.
In another embodiment, the wear resistant coating is positioned on the interior roof guide surface 25, wherein the coating to the interior roof guide surface may be employed in combination with a wear resistant coating to the upper and exterior roof guide surfaces 20, 15, or without the wear resistant coating being applied to at least one of the upper and exterior roof guide surfaces 15, 20. In another embodiment, a wear resistant coating may also be applied to the guide surfaces 30, 35 for the side curtains.
The wear resistant coating may have a thickness ranging from about 0.001 inch to about 0.010 inch, preferably being about 0.002 inch to about 0.004 inch, and may include a self fluxing alloy, oxide, carbide, aluminum bronze alloy, cermet or a combination thereof. Examples of self fluxing alloys that are suitable for providing the wear resistant coating include NiCrB, NiCrBSi, CoNiCrBSi or combinations thereof. Examples of oxides that are suitable for providing the wear resistant surface include alumina (Al203), chromium oxide (Cr203), zirconium oxide (ZrO2), titanium oxide (TiO2) or combinations thereof. Examples of carbides that are suitable for providing the wear resistant surface include tungsten carbide (WC), tungsten-titanium carbide (WTiC), tungsten-chromium carbide (WCrC), chromium carbide (CrC), or combinations thereof.
Cermets that are suitable for providing the wear resistant surface include composites composed of ceramic and metallic materials. The ceramic material may include an oxide, boride, carbide, alumina or combination thereof. The metallic is used as a binder for an oxide, boride, carbide, or alumina. The above described oxides and carbides are suitable as ceramics for cermets within the present invention. Borides may include TiB2, Ti2B, ZrB, ZrB2 and ZrB12. In one embodiment, the metallic elements used are nickel, molybdenum, and cobalt. The cermets may also be metal matrix composites, but are typically less than 20% metal by volume. Preferred cermets include tungsten carbide with a cobalt binder and tungsten carbide with a nickel binder.
Aluminum bronze alloys may include greater than 90 percent copper and less than 10 percent aluminum. It is noted that the above examples are provided for illustrative purposes, and that the wear resistant coating is not deemed to be limited thereto, as the wear resistant coating may be any material having a hardness greater than aluminum and capable of being deposited without substantially decreasing the mechanical properties of extruded aluminum.
The wear resistant coating preferably has a hardness greater than aluminum. Aluminum alloys typically have hardnesses in the range 40 to 160 Brinell. The hardness of the wear resistant coatings can be custom tailored dependent upon material selection. For example, wear resistant coatings of aluminum bronze compositions, in accordance with the present invention, may have a hardness similar, preferably being greater than, the highest hardness levels produced by aluminum alloys and being on the order of about 160 Brinell (approximately 85 Rockwell B Scale) (approximately 170 Vickers Hardness). In some examples, carbide or cermet coatings in accordance with the present invention provide up to 3 to 4 times greater than the highest hardness values for aluminum. For example, in one preferred embodiment of the present invention, a wear resistant coating of NiCrB has a Vickers Hardness on the order of 725.
Referring to
The track 10 may further provide side curtain guide surfaces 30, 35 for rolling engagement of the side curtains 40, 45. Still referring to
In one embodiment of the present invention, in a further effort to facilitate opening and closing of the retractable sliding or rolling doors, the friction between the roller 16, 21, 31, 32 and at least one of the guide surfaces 15, 20, 25 is lowered by the wear resistant coating and/or by the addition of a solid lubricant coatings like teflon, Mo based (e.g. molybdenum disulphide), tin based, ceramic and/or metal based solid lubricants. In the event of the bearings of the rollers 16, 21, 31, 32 cease to function, the lower friction characteristics of the wear resistant coating or solid lubricant against the steel rollers allows the rollers to slide with less force than with the uncoated aluminum rails.
In one embodiment, as opposed to uncoated guide surface composed of extruded aluminum, such as Aluminum Association 6061, an extruded aluminum guide surface having a NiCrB containing wear resistant coating provides an approximately 40% decrease in the guide surface's coefficient of friction, as illustrated in the plot of the coefficient of friction v. time for coated aluminum and uncoated aluminum surfaces depicted in
A coated sample block was prepared by high velocity oxygen fuel (HVOF) thermal spray coating an extruded guide surface of Aluminum Association 6061 alloy with NiCrB to a thickness on the order of about 0.002 inch to about 0.004 inch, and then sectioning the extruded guide surface to sample size. A comparative non-coated sample block of Aluminum Association 6061 alloy was prepared in a similar manner as the coated sample block. Referring to
Another aspect of the present invention is a method of forming the tracks 10 having wear resistive coatings, as described above. The mechanical properties of the aluminum component are not appreciably affected by the coating technology for depositing the wear resistant coating. Preferably, the coating process does not raise the temperature of the aluminum being coated to greater than 100° C. during deposition. Preferably, the coating deposition process includes thermal spray-technology, such as high velocity oxygen fuel (HVOF) thermal spray. The wear resistant coating may alternatively be deposited by detonation thermal spray, low velocity combustion thermal spray, plasma thermal spray, twin wire arc thermal spray, cold gas spray technology, kinetic spray, kinetic metallization, anodizing and electrostatic spray. Further, any deposition technology that may form the above described wear resistant coating locally to the extruded rail with adhesive and hardness properties suitable for improving the wear resistance of the track 1.0, without reducing the mechanical properties of the track, has been contemplated and is within the scope of the invention.
The present invention provides tracks 10 suitable for retractable roof assemblies and side curtains in truck trailers, in which a wear resistive coating applied to the track's guide surfaces 15, 20, 25, 30, 35 substantially reduces the wear to the guide surfaces of the tracks and the rollers of the doors and/or side curtains, hence increasing the service life of guide surfaces and decreasing maintenance.
The present invention further provides a retractable roof assembly having wear resistant tracks that substantially eliminate the incidence of jamming that is typically present in prior retractable roof assemblies having track assemblies that erode over the service life of the vehicle in which the retractable roof assembly is mounted.
While the present invention has been particularly shown and described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in forms and details may be made without departing from the spirit and scope of the present invention. It is therefore intended that the present invention not be limited to the exact forms and details described and illustrated, but fall within the scope of the appended claims.
