Abstract:
A roll-off container in combination with a tilt bed truck which incorporates apparatus for heating the container side walls and bottom of the container with truck exhaust to prevent freezing during inclement weather. The connection between the container and a truck exhaust is made and broken automatically during normal loading and unloading operations of the roll-off container and tilt bed truck.

Description:
BACKGROUND OF THE INVENTION 
     Roll-off containers are often used in the collection and transportation of residential, commercial and industrial refuse such as at construction sites and for the transportation of fly ash and the like. Roll-off containers are typically employed with a tilt bed truck in which the container is loaded onto the truck by tilting the bed and winching of the container onto the bed as the bed is lowered. In some cases, a hydraulic cylinder is employed in place of a winch. Rollers at the container corners and along the tilt bed guide rails ease loading of the container onto the tilt bed. The container bottom typically includes guide rails to interact with the guide rails and rollers on the truck bed which align the container with the truck bed during loading. Such containers are typically open-topped to ease top loading. The containers include a rear door which is opened to allow dumping of the refuse or fly ash after transportation. Because of the open top often the refuse in the container becomes wet and during cold weather can freeze. When such containers are employed to transport fly ash, in cold weather freezing of the moist fly ash is common. Dumping of a container holding frozen refuse or fly ash is difficult or impossible. 
     The use of hot exhaust gases from a tractor to heat a refuse trailer is shown in U.S. Pat. No. 4,623,197 owned by a common assignee as the present application. In U.S. Pat. No. 4,623,197, a refuse trailer is provided which includes an exhaust nipple and a duct system to allow heating of the trailer by the tractor exhaust. However, in the use of roll-off containers, it has heretofore been unknown to provide heat from the truck exhaust to the roll-off container due to the difficulty of making a connection between the truck exhaust and the roll-off container. The motion of the container in both vertical and horizontal directions during loading and unloading makes convenient and secure connecting of the truck exhaust to the roll-off container unknown in the prior art. 
     SUMMARY OF THE INVENTION 
     The present invention provides an apparatus and means for automatically and securely interconnecting a tilt bed truck exhaust to a roll-off container having a load heating duct system. The present invention provides a transfer pipe mounted on the tilting bed of the truck having a first spring-loaded end adapted to interconnect with an exhaust diverter valve when the tilt bed is lowered and a second spring-loaded end adapted to interconnect with a duct fitting on a roll-off container as the roll-off container is loaded. Sure interconnections are provided by spring-loaded expansion joints at both interconnections and by providing the tilt bed frame and roll-off container with precision alignment means. The present invention provides for the alignment and interconnection in both the horizontal and vertical planes required in providing a roll-off container with heat from a truck exhaust. 
     The present invention is particularly well suited for the transportation of moist fly ash in cold weather. Fly ash is often moist and warm when it is loaded, being a by-product of combustion. In cold weather, the moisture trapped in the fly ash tends to freeze making dumping of the material difficult or impossible. The present invention allows for heating of the fly ash in the container with a truck&#39;s exhaust to facilitate dumping. The roll-off container of the present invention, in addition to appropriate duct works for heating also preferably includes a water tight rear door, front and rear splash guards for the open container top and a cover guard to shield the container cover. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a side elevation of a roll-off container, partially cut away according to the present invention. 
     FIG. 2 is a top plan view, partially cut away of a roll-off container showing the present invention. 
     FIG. 3 is a bottom plan view, of a roll-off container according to the present invention. 
     FIG. 4 is a rear elevational view according to the present invention. 
     FIG. 5 is a front elevational view according to the present invention. 
     FIG. 6 is top plan view of a truck tilt bed according to the present invention. 
     FIG. 7 is an elevational view of a truck tilt bed according to the present invention. 
     FIG. 8 is a cross-sectional view along line 8--8 of FIG. 5. 
     FIG. 9 is a cross-sectional view along line 9--9 of FIG. 1. 
     FIG. 10 is a cross-sectional view along line 10--10 of FIG. 1. 
     FIG. 11 is a cross-sectional view along line 11--11 of FIG. 4. 
     FIG. 12 is a cross-sectional view along line 12--12 of FIG. 2. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to FIG. 1, there is shown a side elevational view of a roll-off container in accordance with the present invention. The container 10 is adapted to be carried by a tilt bed truck, not shown, of a type well known in the art. 
     The container 10 is typically a rectangular box shape having a bottom 12, vertical side walls 14a and 14b, a vertical front wall 16 and a rear door 18. Typically, such containers are opened top however, a hinged or removable top may be included if desired. If a top is included, a hatch may be provided for loading. Some containers include a permanent top and are loaded through a tailgate or an opening in a tailgate. Mounted at each corner of the bottom 12 are rollers 20 all having their axis of rotation oriented perpendicular to the longitudinal center line B of the container 10, FIG. 3. The rollers 20 support the container 10 when it is sitting on the ground and facilitate movement of the container 10 during loading and unloading operations. Also oriented on the bottom 12 of container 10 are parallel guide rails 22. The guide rails 22 are oriented parallel to and spaced equidistant from the longitudinal center line B of container 10. Generally accepted industry standards provide for the space 24 between guide rails 22 to be 36.5 inches, and the width of the tilt bed frame 80 to be 35.5 inches so that guide rails 22 engage frame 80 with about a 1/2 inch clearance on each side. The clearance eases initial alignment of the tilt bed frame 80 and guide rails 22 during loading. 
     Guide rails 22 on container 10 are adapted to engage the tilt bed frame 80, FIGS. 6 and 7. The relationship of guide rails 22 and container 10 is such as to form a sled-like device as will be known to those skilled in the art. The tilt bed frame 80 as shown in FIGS. 6 and 7 comprises two parallel rails 82a and 82b oriented longitudinally along a truck and adapted to be raised and lowered in a tilting motion by hydraulic or other suitable means. 
     Extending from frame rails 82a and 82b near the rear 80a of the tilt bed frame are hooks 83 which are adapted to secure the container during transportation. Hooks 83 include a rearwardly facing hook portions 83a which mates with an eye 83b affixed to the container, see FIG. 1. The hook portions 83a engage the eye 83b of container 10 as it is loaded upon the tilt bed frame 80 to control bouncing of the container 10 during transportation. 
     Also extending from tilt bed frame rails 82a and 82b, spaced there along are support rollers 84 adapted to contact container frame rails 22 and support the container 10. The front end 80b of frame guide rails 82a and 82b include upwardly extending hooks 85a and 85b respectively to act as stops during loading of container 10 onto tilt bed frame 80. Hooks 85a and 85b also serve as front retention means to hold container 10 to tilt bed frame 80 during transportation. Extending outwardly from the tilt bed frame rails 82a and 82b near the front 80b of tilt bed frame 80 are camming surfaces 24 more fully described herein below. 
     The guide rails 22 of the container 10 extend beyond the front of container 10, forming guide arms 23 which are adapted to engage camming surfaces 24 on tilt bed frame 80. The engagement of the guide arms 23 with camming surfaces 24 provides for accurate alignment of the container 10 upon tilt bed frame 80 during engagement of the container bell mouth female connector with the exhaust gas transfer fitting as described more fully herein below. The camming surface 24 may alternately be mounted on guide rails 22. The camming surfaces 24, typically slightly less than 1/2 inch in thickness are provided to center the container 10 upon tilt bed frame 80 by providing much closer tolerances between guide rails 22 and tilt bed frame 80 than current industry practice. 
     The loading and unloading of container 10 from the tilt bed frame 80 is accomplished by a truck mounted cable and winch, not shown, in a manner well known in the art. The cable is attached to container 10 at a hook 25 oriented in a notch 28 extending through the front wall 16 and bottom 18 of container 10 between guide arms 23, see FIG. 12. 
     The rear door 18 of container 10, FIG. 4, is preferably pivotally mounted at one vertical edge to container side wall 14b by hinges 30. Rear door 18 is fixed in a closed position by suitable locking means of a type well known in the art and sealed by means such as dogs 32 on side wall 14a and bottom 16. An elastomeric seal 17, FIG. 11, is preferably oriented between door 18 and the container 10 to provide a water tight closure. Seal 17 is preferably formed in a &#34;C&#34; shape from a suitable flexible polymer such as neoprene rubber. When pivoted about hinges 30 to an open position, rear door 18 allows dumping of the contents of container 10 by raising of tilt bed frame 80. 
     Extending between side walls 14a and 14b at the top of container 10 near rear door 18 is a rear splash guard 40. The rear splash guard 40 extends in a longitudinal direction for approximately one-fifth of the overall length of container 10 and is angled slightly downward into the container 10. Rear splash guard 40 controls splashing of the container contents during loading, transporting and dumping of the container. Rear splash guard 40 is preferably angled slightly downward toward the interior of container 10 to control runoff and splashing during loading of container 10. 
     As shown in FIG. 1, oriented along side walls 14a and 14b are vertical reinforcing beams 44 and horizontal reinforcing beams 46. The reinforcimg beams 44 and 46 are hollow to provide a duct work system to circulate hot truck exhaust through the walls and floor of container 10 and thereby heat the container 10 and its contents. Suitable openings 92, FIG. 9, are provided to interconnect the hollow beams 44 and ducts 91, described below, into a duct work system for container 10. A bell mouth female connector 50 is provided on the front wall 16 of container 10 and dual exhaust outlets 57 are provided at the rear of container 10 near the top, as the inlet and outlets respectively for the duct work system. Bell mouth female connector 50 preferably has a slightly frusto-conical shape so as to sealingly engage the transfer fitting 60. The hot exhaust gas from the truck enters the container duct work system at connector 50, flows thorugh the hollow beams 44, ducts 91 and ribs 54, described below, and exits at outlets 57 to provide heat to the container contents. 
     Extending between side walls 14a and 14b adjacent front wall 16 is a front splash guard 94 which preferably extends from front wall 16 longitudinally approximately one-fifth of the length of container 10 to control splashing of the container contents during loading and transportation. Front splash guard 94 is preferably angled slightly downward toward the interior of container 10 to control runoff of materials during loading of refuse or fly ash into container 10. 
     Also oriented across the top of container 10 adjacent front wall 16 is a cover shield 48. Cover shield 48 protects a cover, not shown, for container 10 when it is rolled up upon roller 47. Cover shield 48 also minimizes flapping of cover 49 during transportation by preventing wind from getting underneath cover 49 at the front edge of container 10. 
     The front wall 16 of container 10 includes bell mouth female connector 50 which directs hot exhaust gases to a collector area 52, FIG. 2. The collector area 52 is formed integral with the front wall 16 and is interconnected with the duct work system by ducts 91. Ducts 91 are formed at the intersection of the floor 53 and the walls 14a, 14b and 16. Ducts 91 are provided by fixing a plate 93 at an angle between the floor 53 and the walls 14a, 14b and 16 to define a cavity 91, see FIG. 9. The ducts 91 interconnect the collector area 52 with the duct working system through openings such as 92. The orientation of plates 93 also avoids right angle corners in the container 10 where refuse can become stuck. 
     The duct work system is formed by the interconnection of hollow vertical, 44, and horizontal 46 reinforcements on side walls 14a and 14b and hollow ribs 54 on the floor 53 of container 10, FIG. 2, with ducts 91. The interior floor or bottom 14 of container 10 is provided with reinforcing ribs 54 on the interior of container 10 which are hollow and interconnected with the duct work system, FIG. 8. Because collector area 52 is oriented adjacent connector 50, FIG. 2, an equalization plate 51, shown in phantom in FIG. 2, is provided to split the incoming exhaust gases approximately 2/3 and 1/3 so that all areas of the duct work system receive approximately equal exhaust gas flow. The hot exhaust gases which enter the duct work system of container 10 flow rearwardly from the inlet at connector 50 to outlets 57 through ducts 91 to hollow reinforcements 44 and 46 hollow ribs 54. At the rearof container 10, the gases from reinforcements 44 and 46 pass through openings 47 to be collected in chambers 55a and 55b, FIG. 10. 
     The gases from ribs 54 pass through openings 55 into a hollow beam 56 which extends across the rear of container 10 at the floor 53, FIG. 11. From beam 56 the gases pass through holes 58 into chambers 55a and 55b and out through outlets 57, FIG. 10. 
     The outside of container bottom 12 is provided with reinforcing ribs 13 which angle rearwardly and outwardly from container center line B in a chevron orientation. 
     Bell mouth female connector 50 is adapted to releasably interconnect with transfer fitting 60. Transfer fitting 60 is mounted to the tilt frame 80 of the truck so as to allow hot exhaust gases from the truck to be diverted from the normal exhaust path and directed into the duct work of the container 10 to heat the contents thereof. Transfer fitting 60 includes a first end 62 adapted to fit snuggly into connector 50 as shown in FIG. 8. Precise alignment between container connector 50 and transfer fitting first end 62 is necessary to minimize exhaust gas leaks and damage to the fittings. The desired precise alignment is provided by contact between the guide arms 23 of container 10 and the alignment cams 24 on the tilt frame rails 82a and 82b. The interaction of container guide rails 22 and tilt bed rails 82 generally aligns the container 10 upon the tilt bed frame 80 within the generally accepted tolerances of 1/2 inch between guide rails 22 and tile bed rails 82. The clearance desirable between connector 50 and transfer fitting 60 is such that the precision resulting from the use of alignment cams 24 is necessary. As container 10 is pulled onto tilt bed frame 80 by a winch or hydraulic cylinders, the guide arms 23 and rollers 21 on the tilt bed rails 82 guide and support container 10. As container 10 nears the fully loaded position, precise alignment is provided by alignment cams 24 to insure insertion of first end 62 of transfer fitting 60 into connector 50. Typical industry tolerances of as much as 1/2 inch of play between container 10 and frame rails 82 would result in misalignment and possible damage to connector 50 and/or transfer fitting 60. The precision alignment provided by alignment cams 24 effectively eliminates such misalignment and wear problems. 
     As shown in FIG. 8, the first end 62 of transfer fitting 60 is provided with a spring loaded telescopic arrangement to provide a tight seal in spite of slight variances in positioning between tilt beds and containers. The spring loaded fitting comprises an outer end 64 fitted in a telescopic manner over transfer tube 60. Bolts 65 extend between a first plate 66 on outer end 64 and a second plate 67 mounted on transfer tube 60. The bolts 65 limit the separation of the plates 66 and 67. Oriented around bolts 65, between first plate 66 and second plate 67 are springs 68 to urge the telescoping end 64 away from transfer fitting 60. Thus, as the container 10 is pulled onto the tilt bed frame 80 the connector 50 is guided around transfer fitting 60 by the guide rails 23 and also by alignment cams 24. As connector 50 contacts the outer end 64, the biasing springs 68 provide for a sealing contact in the horizontal plane between container 10 and transfer fitting 60. 
     As shown in FIG. 8, second end 70 of transfer fitting 60 is adapted to interconnect with a segment of the exhaust system of the tilt bed truck. The exhaust system of the truck is provided with a diverter valve 81 which includes an inlet 82 and a first outlet 84 connected to the truck&#39;s normal exhaust system. Diverter valve 81 also includes a second outlet 83 adapted to receive the second end 70 of transfer fitting 60. Diverter valve 81 is provided with a lever 82 or other control means to activate diverter valve 81 and direct the hot exhaust gases from inlet 82 either to the normal exhaust system outlet 84 or to the transfer fitting outlet 83 as desired. 
     The second end 70 of transfer fitting 60 is a second bell mouth female connector adapted to receive a segment 85 of outlet 83 of diverter valve 81. Transfer fitting outlet 83 of diverter valve 81 includes a spring biased, telescoping end 72 to provide a tight interconnection between transfer fitting 60 mounted on the tilt bed frame 80 and the diverter valve 81 mounted to the truck. The spring biased, telescoping end comprises an outer fitting 73 oriented around outlet 83 of diverter valve 81, able to move in a telescoping fashion thereabout. Outer end 73 includes a first plate 76 mounted thereon. A second plate 77 is mounted to the outlet 80. Bolts 75 extend between first plate 76 and second plate 77 to limit separation of the plates 76 and 77. Oriented around bolts 75 between the plates 76 and 77 to urge the outer fitting 73 away from the diverter valve 81 are biasing springs 78. 
     Thus, as the tilt bed 80 is raised and lowered, interconnection between the transfer fitting 60 and diverter valve 81 is provided. The spring biased, telescoping action of outlet 83 of diverter valve 81 provides for a secure interconnection in the vertical plane with each cycle of raising and lowering the tilt bed 80. 
     The container 10 is loaded and unloaded in the same manner as conventional, roll-off containers. However, the transfer fitting 60 automatically connects the exhaust system of the truck to the duct work of the container 10 upon loading to allow heating of the load. Heating of the container load is of particular importance in cold weather handling of wet materials. In such conditions, freezing of materials prevents normal dumping of the material through the back door 18 of the container 10. 
     The interior surfaces of the container may be coated with a high temperature resistant, release material. The material must be resistant to the high temperatures resulting from the circulation of exhaust gases. Exhaust gases typically may reach a temperature of about 470° F. Temperatures within the container duct work system reach approximately 400° F. during normal operations and may be slightly higher in some situations. The desired coating must be resistant to these temperatures and strong enought to resist abrasion and chipping caused by the fly ash during loading and unloading operations. The coating further must present a smooth surface which resists fly ash adhesion. It has been found that a high temperature silicone resin coating such as SC-660 produced by ACX Corporation of Baclif, Tex., is effective. Such coating is applied to a clean surface, such as a sand blasted surface. The coating is preferably applied in a series of layers, for example two light coats which are allowed to partially dry followed by a thicker final coat, so as to provide a smooth covering having a dry film thickness of at least two to three mils. The coating is cured at a temperature of approximately 400° F. by the application of heat from the container duct work system. 
     It should be understood that the foregoing description and drawings of the invention are not intended to be limiting, but are only exemplary of the inventive features which are defined in the claims.