BRIEF DESCRIPTION OF THE DRAWINGS
These and further features of the invention will be apparent with reference to the following description and drawings, wherein:
FIG. 1 is an exploded perspective view of a roller assembly in accordance with some embodiments of the present invention;
FIG. 2 is an elevational front view of a roller in accordance with some embodiments of the present invention;
FIG. 3 is a cross section, taken at line 3-3 in FIG. 2, of a roller in accordance with some embodiments of the present invention;
FIG. 4 is a side view of a ferrule in accordance with some embodiments of the present invention;
FIG. 4A is a schematic blown-up, broken-way view of a portion of the ferrule;
FIG. 4B is a cross-sectional view of the ferrule;
FIG. 5 is a side view of a shaft that has been cold-headed in accordance with some embodiments of the present invention;
FIG. 6 is a perspective view of the roller assembly of FIG. 1, except that the roller assembly shown in FIG. 6 has been assembled;
FIG. 7 is a second perspective view of the roller assembly of FIG. 6; and
FIG. 8 is an exemplary over head flexible door to which roller assemblies are attached in accordance with some embodiments of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows an exploded perspective view of one embodiment of a roller assembly 10 of the present invention. The roller assembly 10 basically comprises a roller 12, a shaft 14, and one or more ferrules 16. Preferably, as shown in FIG. 1, there are two ferrules 16. Also, in the preferred embodiments, a washer 18 is part of the roller assembly 10. All of these parts are assembled along an axis 20 so as to allow the roller 12 to rotate around the axis 20. The roller assembly 10 of the present invention is especially well suited for use in a flexible over head door such as a garage door or a rolling over head door on a commercial truck.
As can be seen, for example, in FIGS. 1-3, the roller 12 has first and second sides 22a and 22b, a rolling surface 24, and an interior bore 26 extending through the roller 12 and centered along the axis 20. The diameter of the interior bore 26 allows the shaft 14 to fit within the bore, as will be explained further herein. The rolling surface 24 comprises the surface of the roller 12 that contacts the track or surface upon which the roller 12 rolls. In one application the roller 12 rolls within a linear track 50, such as that shown in FIG. 8.
In the preferred embodiments of the roller 10, the interior bore 26 has radial edges 28. Preferably, both the edges of the bore 26 on side 22a and the edges of the bore 26 on side 22b of the roller 12 have a radial configuration, but some embodiments may have a radial edge 28 only on one of sides 22a or 22b. In the illustrated embodiment the shape of the radial edge 28 helps to seat the ferrules 16.
As illustrated, side 22a of the roller 12 preferably has a recess 32. Also, side 22b preferably has a recess 32. The recess 32 comprises a depression in the side 22a and/or 22b that is adapted to accommodate or receive the ferrule 16. In the preferred embodiments, the recess 32 comprises a circular depression that has a depth 22c of at least 5% of the total maximum width of the roller 12.
The details of the configuration of ferrule 16 are best seen in FIGS. 4, 4B and 4C. As shown in FIG. 4B, ferrule 16 preferably includes an embossed portion 16f that helps to strengthen the outer portion of the ferrule 16, and it also serves to minimize contact between the outer portion 16f and the roller 12.
Also, in the preferred embodiments of the roller 12, the interior bore 26 has one or more grooves 30 for catching or containing dust, dirt, or other particles that might enter the interior bore 26. The grooves 30 thereby help to prevent the interior bore 26 from being scratched and damaged. Preferably as shown in the drawings, the grooves 30 resemble six semi-cylinders having axes that are parallel to the previously mentioned axis 20 of shaft 14. However, the grooves 30 can be of any appropriate shape and number suitable for catching dust or other particles.
The roller 12 is made of a polymer or rubber-like material. Materials that the roller 12 might be made of include, but are not limited to: thermoplastic materials such as polystyrene, acrylics, polyethylene, PET, urethanes, olefins including propylene homopolymer and copolymers, halogenated materials including PTFE and PVC, and engineering thermoplastics such as nylon, ABS, fluoropolymer, polyethetherketone, polyphenylene sulfide and polysulfone materials. A thermoset polymer may also be used such as an epoxy, a melamine, a polyester, a polyurethane or a urea containing thermoset. In a preferred embodiment roller 12 comprises a fairly rigid thermoplastic polyurethane compound.
The shaft 14 is preferably an elongated cylindrical bar made of some type of metal. One example of a preferred metal is low carbon steel (e.g., 1008 steel), but any suitable sturdy material may be used to comprise the shaft 14 such as, for example, aluminum, brass, copper or stainless steel. The shaft 14 fits through the interior bore 26 so as to allow the roller 12 to roll around the shaft 14. The shaft comprises an outer end 14a, an inner end 14b, and, preferably, a shoulder 14c. The shoulder 14c serves to prevent the roller 12 from slipping or moving towards the inner end 14b of the shaft 14. The shoulder 14c may comprise an integrally formed extension of the shaft 14 and not a separate part that has been coupled to the shaft 14. However, some embodiments of the present invention may comprise a separate shoulder 14c that is coupled to the shaft 14 to prevent the roller 12 from moving towards the inner end 14b. More particularly, the shoulder 14c may comprise an adapter that serves to couple two separate pieces of shaft 14a and 14b together. By using an adaptor as part of the assembly, increased flexibility is afforded in that shafts 14a and 14b of various lengths can be selected to accommodate different applications and also rollers of various outer diameters can be used according to the requirements of a particular application. This concept is also shown in Espey U.S. Pat. No. 6,536,077 the disclosure of which in incorporated by reference herein in its entirety.
As mentioned previously, the preferred embodiments of the roller assembly 10 include a washer 18. The washer 18 is intended to help reduce or minimize friction between parts adjacent to it. Preferably, the washer 18 is generally ring-shaped and comprised of some type of polymer such as nylon, for example. However, the washer 18 may comprise a metal such as steel, copper, brass or bronze. Also, the roller assembly 10 is preferably assembled so that the washer 18 is located on the outer end 14a of the shaft 14 between and adjacent to the shoulder 14c and the ferrule 16 that is coupled to side 22a of the roller 12.
The ferrule 16 serves to guide the shaft 14 there through and help to keep it aligned within the interior bore 26 of the roller 12. Preferably, the guiding surfaces of the ferrule 16 are curved so that the ferrule 16 is shaped like a truncated trumpet, as shown in the drawings.
As shown in FIG. 1, the roller assembly 10 preferably has two ferrules 16—one on each side of the roller 12. In the embodiment shown, each ferrule 16 is substantially identical and has a first inner edge 16a and a second outer edge 16b. The ferrule 16 also includes an outer rolling surface 16c and an inner rolling surface 16d. In the preferred embodiments, one or both of the ferrules 16 are disposed against the roller 12 so that inner edge 16a seats within the interior bore 26 and outer edge 16b seats at least in part within the recess 32 of one of the sides 22a or 22b of the roller 12. Also, the outer diameter of inner edge 16a preferably substantially corresponds with the diameter of the interior bore 26, and the outer diameter of outer edge 16b substantially corresponds with the diameter of the recess 32. The correspondence between the diameter of the interior bore 26 and the outer diameter of the edge 16a helps to align the shaft 14 within the bore 26 and thereby reduce wear on the roller assembly 10. Also, such configuration allows two degrees of rolling, the roller 12 can roll on outer rolling surface 16c, and the inner rolling surface 16d can roll along the outer surface of the outer end 14a of the shaft 14.
As best seen in FIG. 4A the rolling surface 16c has a tapered portion 16m of decreasing diameter and a flat portion 16n having a constant diameter. Tapered portion 16m conforms in shape substantially to radial edge 28 of interior bore 16. Preferably, tapered portion 16m extends along at least 25% and preferably along at least 35% of the width of the outer rolling surface 16c. The height h of tapered portion 16m is at least 5%, and preferably at least 8% of the diameter of the inner edge 16a.
The ferrules 16 may be formed from any one of a variety of materials such as polymers or metals, however, in preferred embodiments of the present invention, the ferrule 16 is made of a metal that resists rust and wear such as stainless steel. A preferred stainless steel is grade 303. However, the ferrule 16 may be made of any other metal or suitably durable material such as a carbon steel, high strength brass or bronze. It will be appreciated that although ferrule 16 is preferably formed from a separate piece of metal or material, it would be possible to form one of the ferrules as an integral piece from shaft 14. For example, one could use forging techniques to integrally form the inner ferrule from shaft 14, and thus also eliminate the need for shoulder 14c.
When the roller assembly 10 is assembled, as in FIGS. 6 and 7 for example, the roller 12 is able to rotate within the end 14a of the shaft 14 and around the axis 10. The ferrules 16, whether there are one or more, preferably are seated snugly against the roller 12 and therefore rotate with the roller 12, but not too snuggly as to prevent the rotation of the ferrules 16. In the embodiments having a washer 18, the washer 18 preferably fits snugly around the shoulder 14c of the shaft 14 and against the ferrule 16 coupled to side 22a of the roller 12, as seen best in FIG. 7. The roller 12 is coupled to the shaft 14 so that the roller 12 does not slide off of the outer end 14a of the shaft 14. In the preferred embodiments, the end 14a of the shaft 14 is cold-headed to the roller 12, as will be explained hereafter. However, any suitable means for keeping the roller 12 on the shaft 14 may be employed, including but not limited to a spring retainer, or a press fit cap or threaded nut (not shown) coupled to the distal end of the shaft 14.
FIG. 5 shows a shaft 14 (minus the roller 12) that has been cold headed. In other words, the end 14a of the shaft 14 has been forced or pounded outwardly so as to form a head 14d and a lip 14e. The lip 14e is of a diameter greater than the diameter of the sections of the shaft 14 immediately adjacent to the lip 14e. The lip 14e therefore prevents the roller 12 from coming off of the outer end 14a of the shaft 14. FIGS. 6 and 7 show two perspectives of an assembled roller assembly 10 in which the roller 12 is cold-headed to the shaft 14. In these embodiments, the roller 12 is shown to be snugly secured between the lip 14e and the shoulder 14c of the shaft 14.
In shall be noted that, in the preferred embodiments, the interior bore 26 is preferably lubricated with petroleum jelly or any other suitable lubricant that will not deteriorate the roller 12 yet still has sufficient viscosity to stick to the interior bore 26. Additional lubricant can be provided to the assembly 10 by using a lubricant infused polymer to produce roller 12.
FIG. 8 shows multiple roller assemblies 10 coupled to a flexible over head door or closure member comprising several elongated segments 52 that are coupled together to form an enclosure for an opening or entrance to a building, commercial truck, or other enclosable area. FIG. 8 shows the roller assemblies 10 coupled to the sides of the elongated segments 52 so as to allow the roller assemblies 10 to travel within tracks 50 and thereby allow the door to open and close. Preferably, the roller assemblies are coupled to a door that is designed, as in FIG. 8 for example, to move between a closed upright position to an open overhead position. However, some flexible doors of the present invention might move between a closed position to an open position that is to the side (instead of over head) of the closed position. Applicant hereby incorporates by reference U.S. Pat. Nos. 3,176,757 and 2,625,221 which disclose the general configuration of an over head door in which the roller assembly of the present invention may be employed.
While the preferred embodiment of present invention has been described herein with particularly, it is noted that the invention is capable of numerous modifications rearrangements, and substitutions of parts without departing from the scope and spirit of the present invention. Accordingly, the invention is not limited to the particular structures described herein, but rather is only to be defined by the claims appended hereto.
Patent Application
20070289091
