Abstract:
A transition sleeve is inserted into a transition tube of a vacuum system of a vacuum sweeper. The transition sleeve extends the useful life of the transition tube by sacrificially wearing instead of the transition tube. Such wear arises from abrasive grit and other materials swept up by the vacuum sweeper. The transition sleeve is desirably formed using wear-resistant materials. The transition sleeve can include a flange at one end to allow the transition sleeve to be held in the transition tube without using fasteners or bonding agents. A first portion of an interconnection structure is provided at the other end of the transition sleeve and engages with a second portion of the interconnection structure provided at a first end of an extension sleeve to connect the extension sleeve to the transition sleeve. The extension sleeve allows the transition sleeve to be used with transition tubes of varying lengths.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to vacuum-type street sweepers. 
     2. Related Art 
     Vacuum sweepers, especially those used for parking lots and on roadways and sidewalks, are well known in the industry. Various types of vacuum sweepers, from commercial units to small personal units, are manufactured by a number of companies, including Elgin Sweeper Company (e.g., GeoVac), Schwarze Industries (e.g., A-series, EV-series, M-series and S-series), Python Manufacturing, Inc. (e.g., Raven 45), and Tymco Inc. (e.g., Models 210, 435, OST-4, 600, OST-6, and 600 HSP). Typically, vacuum sweepers include transition tubes, such as air flow transition tubes, air intake tubes and hopper tubes, that help facilitate moving the swept material from one or more vacuum heads into a hopper. 
     Conventionally, these transition tubes are typically constructed of metals, including steel, steel alloys or aluminum, and various polymers. Transition tubes are subject to a great deal of wear and tear due to the impact and abrasion that occurs as the vacuumed particles and other fluent materials move through the transition tubes from the vacuum heads into the hopper. 
     SUMMARY OF THE INVENTION 
     The typical useful lifetime of most metal transition tubes is approximately 160 hours to 300 hours. After such periods of use, the frictional and corrosive wear caused by the interaction between the vacuumed particles and the interior of the transition tubes causes the metal transition tubes to wear and become unstable. Near or at the end of their useful life, transition tubes must be replaced or repaired. 
     Attempts to extend the useful lifetimes of these transition tubes have included using metal sleeve inserts that are inserted into the transition tubes to ameliorate the abrasive conditions experienced by transition tubes during use. Metal sleeve inserts have a number of disadvantages. Like the metal transition tubes, they are designed to protect, the metal sleeve inserts quickly wear out. The typical useful life of a metal sleeve insert is approximately 160 to 300 hours. In addition, removing and replacing worn metal sleeve inserts may be very difficult. Such metal sleeve inserts are typically worn and misshapen as a result of the abrasive and damaging conditions caused by the abrasive material passing through them. In addition, metal sleeve inserts are typically bolted or otherwise fastened to a transition tube in order to maintain the metal insert within the transition tube. However, the fasteners used to secure the metal sleeve inserts in the transition tubes are subject to the same corrosive, abrasive and destructive conditions resulting from the swept material. As such, the fasteners typically wear out quickly and need to be replaced often. In addition, the metal sleeve inserts are themselves significantly expensive to replace. 
     Other attempts to increase the useful life of transition tubes include affixing or molding elastomers, such as rubber or polyurethane, to the transition tubes using fasteners such as screws and/or bonding agents such as glue. However, as discussed above, the abrasive material passing through the transition tubes typically takes little time to destroy or damage the fastener heads, causing the elastomers to slip or move inside the transition tubes. Using bonding agents to affix the elastomers to the transition tubes also has disadvantages. It is very difficult to seamlessly glue elastomers to transition tubes. For example, the bonding agents and elastomers commonly experience different thermal expansion characteristics, which causes stress and cracks that allow the swept abrasive material to attack and destroy the bond between the elastomer and the transition tube. Furthermore, bolting or gluing the elastomers to the transition tubes is labor intensive and makes it difficult to make field repairs to the transition tubes. 
     Furthermore, an affixed or molded elastomer typically does not wear evenly. As a result, certain portions of the elastomer wear out before other portions, making it difficult to replace the elastomer liner as it wears or to otherwise service the transition tube without replacing the transition tube in its entirety. Furthermore, once a section of elastomer is compromised, the steel previously covered by that section of elastomer is exposed and subject to wear. Ultimately, the transition tube will fail and need to be replaced in its entirety. As discussed above, this replacement is costly and time consuming. Further, replacing these molded transition tubes is often more costly than replacing a typical metal transition tube. 
     This invention provides an inner protective barrier for a transition tube. 
     This invention separately provides an interior protective barrier for a transition tube that is installed, serviced and/or replaced with little difficulty, downtime and/or expense. 
     This invention separately provides an inner protective barrier for a transition tube that is relatively resistant to wear compared to conventional transition tubes and inserts for transition tubes. 
     This invention separately provides an inner protective barrier that is easily secured to the transition tube. 
     This invention separately provides an inner protective barrier that can be secured to a transition tube without having to fasten or bond the inner protective barrier to the transition tube. 
     This invention separately provides an inner protective barrier that can be easily rotated or otherwise adjusted to increase its useful lifetime and improve its effectiveness. 
     This invention separately provides an inner protective barrier that may be interlocked with at least one extension sleeve to extend the overall length of the protective barrier. 
     This invention separately provides a long-life inner protective barrier for a transition tube that is relatively inexpensive to manufacture. 
     In various exemplary embodiments, the transition tube comprises a cylindrical sleeve body having a longitudinal opening passing through the sleeve body and a flange at one end of the transition tube. The cylindrical sleeve forms an easily installed, maintained and replaced protective barrier that is removably retained within the transition tube without requiring the use of individual fasteners or bonding agents. In one embodiment, the transition sleeve may be engaged with at least one extension sleeve to extend the overall length of the transition sleeve. 
     These and other features and advantages of various exemplary embodiments of the apparatus according to this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of various devices, and/or structures according to this invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Various exemplary embodiments of the systems according to this invention will be described in detail, with reference to the following figures, wherein: 
         FIG. 1  is a perspective view of a vacuum head assembly that includes one exemplary embodiment of a transition sleeve according to this invention; 
         FIG. 2  is a perspective view showing the transition sleeve of  FIG. 1  in greater detail; 
         FIG. 3  is a cross-sectional view of the transition sleeve shown in  FIG. 1 ; 
         FIG. 4  is a cross-sectional view showing in greater detail one exemplary embodiment of a first end and a flange of a transition sleeve according to this invention; 
         FIG. 5  is a cross-sectional view of one exemplary embodiment of a second end of a transition sleeve according to this invention; 
         FIG. 6  is a perspective view of a second exemplary embodiment of a transition sleeve and a first exemplary embodiment of an extension sleeve according to this invention; 
         FIG. 7  is a cross-sectional view of an exemplary embodiment of a second end of the second exemplary transition sleeve and a first end of the first exemplary extension sleeve according to this invention; 
         FIG. 8  is a cross-sectional view showing in greater detail the exemplary embodiment of the second end of the transition sleeve and the first end of the first exemplary extension sleeve shown in  FIG. 7 ; and 
         FIG. 9  is a perspective view of a second exemplary embodiment of a transition sleeve and a second exemplary embodiment of an extension sleeve according to this invention. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     This vacuum sweeper transition sleeve may be inserted into a transition tube such as an air flow transition tube, an air intake tube, a hopper tube and the like to prolong the life of the transition tube.  FIG. 1  is a perspective view of a typical vacuum head assembly  100  for a vacuum sweeper and a first exemplary embodiment of a transition sleeve according to this invention. A transition tube  120  of the vacuum head assembly  100  helps move swept and other fluent material from the vacuum head  110  to a collection system, such as a hopper. Some transition tubes  120 , such as an air flow transition tube or an air intake tube, are typically coupled to the vacuum head  110  by a flexible conduit  122 . Other transition tubes, such as a hopper tube, are connected to a hopper of the vacuum sweeper. The vacuum head assembly  100  connections may not be direct. For example, the vacuum head assembly  100  may also include a number of gaskets engaged throughout the vacuum head assembly  100  to provide a seal between the vacuum head  110 , the flexible conduit  122 , the transition tubes  120  and the hopper. In one exemplary embodiment, a transition sleeve  130  may be inserted into the transition tube  120  to extend the life of the transition tube  120 . 
       FIG. 2  is a perspective view showing in greater detail one exemplary embodiment of the transition sleeve  130  shown in  FIG. 1 . In the exemplary embodiment shown in  FIG. 2 , the transition sleeve  130  comprises a generally cylindrical or tubular sleeve body  132  having a longitudinal opening or passageway. In various exemplary embodiments, the transition sleeve  130  has a first end  131  and a second end  133 . In various exemplary embodiments, at least the first end  131  of the transition sleeve  130  has a flange  134 . In various exemplary embodiments, the flange  134  may extend along the entire circumference of the first end  131  of the transition sleeve  130 . The transition sleeve  130  can be formed using various abrasion resistant materials. Such materials include one or more of rubber and polymers, such as polyethylene and particularly ultra-high molecular weight polyethylene, polypropylene, polyurethane, nylon, acrylics or acrylics with embedded fibers. If nylon is used, nylon 6, nylon 6-6 and nylon 11 can be used. Any of these materials may be 100% virgin or may incorporate up to 100% of recycled material. However, it should be appreciated that any material that provides sufficient abrasion resistance can be used to form the transition sleeve  130 . 
     In various exemplary embodiments, the flange  134  is made of the same material as the sleeve body  132 . In various other exemplary embodiments, the flange  134  is made of a similar material such as a polymer, but can be made of a distinct or different material. However, any appropriate material, such as a polymer, or combination of such materials, may be used to construct the sleeve body  132  and/or the flange  134 . These materials include, but are not restricted to, rubber, polyethylene, polypropylene, polyurethane, nylon, acrylic and acrylic with embedded fibers. If nylon is used, nylon 6, nylon 6-6 or nylon 11 can be used. In addition, in various exemplary embodiments, the sleeve body  132  and/or the flange  134  may comprise a co-extrusion that combines two or more layers of various extrudable materials, such as resins, to form one composite material. Using such materials for the transition sleeve  130  can extend the life of a transition tube such that the transition tube itself may never need to be replaced or repaired when the transition sleeve  130  is inserted into the transition tube. 
     In various exemplary embodiments, the material used to form the transition sleeve  130  has a Shore hardness in the range of about 50 A to about 70 D. In various exemplary embodiments, the material used to form the transition sleeve  130  has a hardness in the range of about 83 to about 87 durometer Shore A hardness. In various exemplary embodiments, the material used to form the transition sleeve  130  has a hardness of about 90 to about 93 durometer Shore A hardness. In various exemplary embodiments, the material used to form the sleeve body  132  and/or the flange  134  is desirably soft enough that the sleeve body  132  and/or the flange  134  can be squeezed and/or collapsed for ease of installation into a transition tube. 
     In various exemplary embodiments, the transition sleeve  130  is generally cylindrical in shape. It should be appreciated, however, that the transition sleeve  130  may be any shape that is appropriate for a given transition tube. It should also be appreciated that the flange  134  need not be cylindrical in shape. The flange  134  may take any shape appropriate to fit a particular transition tube. Furthermore, while in various exemplary embodiments, the flange  134  and the sleeve body  132  may have similar cross-sectional shapes and/or inner and/or outer contours, the flange  134  need not use the same contour as the sleeve body  132 . For example, Tymco, Inc. has manufactured a street sweeper having a transition tube that comprises a tube body that is generally cylindrical in shape but transitions to a square head. In various exemplary embodiments, a transition sleeve  130  having a cylindrical sleeve body  132  with a square-shaped flange  134  is particularly useful for such a transition tube. 
     In various exemplary embodiments, the outer diameter of the flange  134  and the length and outer diameter of the sleeve body  132  depend on the type and dimensions of the particular transition tube a particular transition sleeve  130  is adapted to fit. In various exemplary embodiments, the overall length of the transition sleeve  130  is from about 10 inches to about 14 inches and the diameter of the exterior of the sleeve body  132  is about 8 inches to about 11 inches. In some exemplary embodiments, the overall length of the sleeve body  132  is approximately about 12 inches and the outer diameter of the sleeve body  132  is approximately about 9.5 inches. In various exemplary embodiments, the sleeve body  132  has a substantially uniform thickness, which is, in various exemplary embodiments, about 0.20 inches to about 0.35 inches thick. However, it should be appreciated that the sleeve body  132  may be any length and/or thickness that may be suitable for use with a particular transition tube. 
     In various exemplary embodiments, the flange  134  and the sleeve body  132  are molded together or otherwise integrally formed. In various exemplary embodiments, the transition sleeve  130 , including the flange  134 , is manufactured using open cast molding. In various other exemplary embodiments, the transition sleeve  130  is extruded. When injection-molded, the transition sleeve  130  is formed using injection molded or spin cast plastic, such as ultra-high molecular weight polyethylene. It should be appreciated, that, in various exemplary embodiments, the flange  134  and the sleeve body  132  are formed as separate parts and connected, affixed or bonded together using epoxy, glue and/or the like, or any known or later-developed agents and/or methods. 
     As shown in  FIGS. 3 and 4 , the flange  134  extends outwardly from the outer surface of the sleeve body  132 . In various exemplary embodiments, the width W f  of the flange  134  ranges from about 0.25 inches to about 0.75 inches. These values, however, may vary depending on the particular materials that are used and/or when the dimensions of the transition tube allow or require. 
     In various exemplary embodiments, the height H f  of the flange  134  ranges from about 0.12 inches to about 0.38 inches. These values may, however, may vary depending on the particular materials that are used and/or a number of other factors, including, for example, the weight of the particular transition sleeve  130 , the dimensions of the transition tube, and the dimensions of any gaskets, seals and/or the like used near the end of the transition tube. 
     As shown in  FIG. 4 , in various exemplary embodiments, the surface of the flange  134  extending from the sleeve body  132  tapers away from the sleeve body  132  at a determined angle. In various exemplary embodiments, the determined angle of the taper of the flange  134  from the sleeve body  132  is about 0 degrees to about 30 degrees. In various exemplary embodiments, the interior or inner edge of the first end  131  of the sleeve body  132  of the transition sleeve  130  is beveled. In various exemplary embodiments, the angle of the bevel of the inner edge of the sleeve body  132  is about 30 degrees to about 60 degrees. 
     As shown in  FIGS. 3 and 5 , the second end  133  of the sleeve body  132  of the transition sleeve  130  may comprise any of a variety of shapes. In various exemplary embodiments, the inner edge of the second end  133  is substantially square. In various other exemplary embodiments, the inner edge of the second end  133  is beveled. A beveled edge can improve the flow of material past the inner edge of the second end  133  and/or reduce wear and tear on the transition sleeve  130 . 
     It should be appreciated that the longitudinal length of the transition sleeve  130  will typically depend upon the type and dimensions of the particular transition tube  120  that the transition sleeve  130  is adapted to fit. In various exemplary embodiments, the transition sleeve  130  is manufactured at a particular length useable with a number of different types of known or later-developed transition tubes. If a transition sleeve  130  shorter than the standard manufactured length is desired, the transition sleeve  130  can be cut to remove the excess length. This allows the transition sleeve  130  to better fit a particular transition tube. 
       FIG. 6  shows a second exemplary embodiment of a transition sleeve  230  according to this invention. The exemplary embodiment of the transition sleeve  230  illustrated in  FIG. 6  is particularly useful when a longer transition sleeve  230  is useful or desirable. As shown in  FIG. 6 , the transition sleeve  230  can be combined with at least one extension sleeve  240  to extend the overall length of the transition sleeve  230 . Additional extension sleeves  240  can be added to the initial extension sleeve  240  connected to the transition sleeve  230  to provide a transition sleeve  230  having any desired additional length. 
     In the exemplary embodiments shown in  FIGS. 6-8 , the extension sleeve  240  is connected to the transition sleeve  230  using a groove structure  236  provided near the second end  233  of the transition sleeve  230  and a tongue structure  242  provided near a first end  241  of the extension sleeve  240 . It should be appreciated that the tongue and groove structures  242  and  236  can be instead provided on the opposite one of the extension and transition sleeves  240  and  230 , respectively. In operation, in one embodiment, the tongue structure  242  engages the groove structure  236  and interconnects the extension sleeve  240  with the transition sleeve  230  to help prevent movement of the extension sleeve  240  with respect to the transition sleeve  230 . In other various exemplary embodiments, a keyhole structure is used to interlock an extension sleeve  240  to the transition sleeve  230 . In the exemplary embodiment shown in  FIG. 9 , the inner side of the second end  233  of the transition sleeve  230  may be provided with internal threads  238 , while the extension sleeve  240  is provided with corresponding external threads  244 , such that the extension sleeve  240  can be simply screwed onto the transition sleeve  230 . 
     In operation, a transition sleeve  130  or  230  according to this invention is inserted into a transition tube  120 . In various exemplary embodiments, the transition sleeve  130  or  230  is orientated and aligned with the transition tube  120  and inserted into the transition tube  120  until the flange  134  or  234  abuts against a first edge of the transition tube  120 . In various embodiments, the flange  134  or  234  extends between the end  124  of the transition tube  120  and another system member, such as the flexible conduit  122  or the hopper, so that it is securely held in place. Once secured, the flange  134  or  234  abutting against the end  124  of the transition tube  120  prevents the transition sleeve  130  or  230  from sliding or rotating. Various gaskets, seals and/or the like can be used with the flange  134  or  234  to create a better seal between the transition tube  120  and the vacuum head  110 , the flexible conduit  122 , and/or the hopper. 
     The flange  134  or  234  enables the transition sleeve  130  or  230  to be removably retained within a transition tube  120 . That is, the flange  134  or  234  allows the transition sleeve  130  or  230  to be easily secured into position but also easily removed. The ability for a service person to easily insert and remove the transition sleeve  130  or  230  substantially reduces downtime and maintenance time. In addition, the relatively easily detachable transition sleeve  130  or  230  allows the transition sleeve  130  or  230  to be readily replaced in the field. Using the flange  134  or  234  to secure the transition sleeve  130  or  230  also allows the transition sleeve  130  or  230  to be easily rotated and re-secured in a new position. Certain areas of the transition sleeve  130  or  230  may wear faster than other areas. The useful life of the transition sleeve  130  or  230  may be substantially improved by rotating the transition sleeve  130  or  230  in the transition tube  120  and securing the transition sleeve  130  or  230  in a new position. 
     If desired, the transition sleeve  130  or  230  may be replaced by sliding the transition sleeve  130  or  230  out of the transition tube  120  and installing a new transition sleeve  130  or  230  into the transition tube  120 , as previously described. Removing and replacing the transition sleeve  130  or  230  may take place as desired or needed due to any number of circumstances, such as the wear and tear on the transition sleeve  130  or  230  and/or transition tube  120 , damage to the transition sleeve  130  or  230  and/or transition tube  120 , and/or to facilitate the cleaning of the transition tube  120  and/or the transition sleeve  130  or  230 . 
     While this invention has been described in conjunction with the exemplary embodiments outlined above, various alternatives, modifications, variations, improvements and/or substantial equivalents, whether known or that are or may be presently foreseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the exemplary embodiments according to the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit or scope of the invention. Therefore, the invention is intended to embrace all known or earlier developed alternatives, modifications, variations, improvements and/or substantial equivalents.