Patent Publication Number: US-9845191-B2

Title: Ejector track for refuse vehicle

Description:
BACKGROUND 
     Refuse vehicles collect a wide variety of waste, trash, and other material from residences and businesses. Operators use the refuse vehicle to transport the material from various waste receptacles within a municipality to a storage or processing facility (e.g., a landfill, an incineration facility, a recycling facility, etc.). To reduce the requisite number of trips between the waste receptacles and the storage or processing facility, the refuse may be emptied into a collection chamber (e.g., a hopper) of the refuse vehicle and thereafter compacted. Such compaction reduces the volume of the refuse and increases the carrying capacity of the refuse vehicle. The refuse is compacted in the collection chamber by an ejector that is forced against the refuse by actuators (e.g., pneumatic cylinders, hydraulic cylinders). To keep the ejector aligned with the walls of the collection chamber, portions of the ejector are constrained by tracks or rails. 
     Traditionally, an ear on each side of the ejector slides within a “C” channel formed along the collection chamber. Compacting forces and forces due to the weight of the ejector are applied at the interface between the ear and the ejector. However, the ear is supported by the body of the refuse vehicle in a location laterally outward from the interface between the ear and the ejector. The application of forces laterally inward from the “C” channel produces a cantilever loading arrangement, which increases the stresses on the ear, the ejector, and the vehicle body. The structural elements of these components (e.g., the plates, gussets, etc.) must be sized to carry this increased load, thereby increasing the weight of the refuse vehicle. Despite such an increase in weight, a cantilevered loading configuration remains the traditional method for supporting the ejector of a refuse vehicle. 
     SUMMARY 
     One embodiment of the invention relates to an ejector for a refuse vehicle including a structural frame, a first shoe, and a second shoe. The structural frame includes a first side plate offset from a second side plate, and the distance between the first side plate and the second side plate defines a side plate spacing. The first shoe is coupled to the first side plate and includes a first surface configured to interface with a first ejector track. The second shoe is coupled to the second side plate and includes a second surface configured to interface with the second ejector track. A lateral spacing between the first surface and the second surface is less than or equal to the side plate spacing such that loading imparted on the structural frame is transmitted directly into the first ejector track and the second ejector track. 
     Another embodiment of the invention relates to a body assembly for a refuse vehicle. The body assembly includes a plurality of panels, a first ejector track, and a second ejector track. The plurality of panels define a chamber configured to contain a volume of refuse therein. The first ejector track is coupled to a first of the plurality of panels and includes a first upper wall including an outer edge and an inner edge and a first lower wall including an outer edge and an inner edge. The second ejector track is coupled to a second of the plurality of panels and offset from the first ejector track. The second ejector track includes a second upper wall including an outer edge and an inner edge and a second lower wall including an outer edge and an inner edge. The distance between the inner edge of the first upper wall and the inner edge of the second upper wall defines an upper wall spacing, and the distance between the inner edge of the first lower wall and the inner edge of the second lower wall defines a lower wall spacing. The upper wall spacing is greater than the lower wall spacing, and the first lower wall and the second lower wall define surfaces configured to directly support side plates of an ejector. 
     Still another embodiment of the invention relates to a refuse vehicle that includes a chassis, a body assembly, a ram, and a track. The body assembly is coupled to the chassis and includes a plurality of panels defining a chamber configured to contain a volume of refuse therein. The ram is positioned within the collection chamber and includes a side plate coupled to at least one of the plurality of panels with a shoe. The track is fixed to at least one of the plurality of panels and configured to receive the shoe. The track includes a lower wall positioned laterally below the side plate of the ram such that the forces and moments on the ram are transmitted directly into the track. 
     Yet another embodiment of the invention relates to a body assembly for a refuse vehicle. The body assembly includes a plurality of panels that extend along a longitudinal direction and define a chamber configured to contain a volume of refuse therein. The body assembly further includes a head wall extending laterally across the longitudinal direction. The head wall is coupled to the plurality of panels to form a corner. The corner is configured to receive an end of an actuator that compresses the volume of refuse. 
     The invention is capable of other embodiments and of being carried out in various ways. Alternative exemplary embodiments relate to other features and combinations of features as may be recited in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements, in which: 
         FIG. 1  is a perspective view of a front-loading refuse vehicle, according to an exemplary embodiment; 
         FIG. 2  is a perspective view of a side-loading refuse vehicle, according to an exemplary embodiment; 
         FIG. 3  is a front perspective view of a body for a refuse vehicle, according to an exemplary embodiment; 
         FIG. 4  is a rear perspective view of the body for a refuse vehicle, according to an exemplary embodiment; 
         FIG. 5  is front perspective view of an ejector for a refuse vehicle, according to an exemplary embodiment; 
         FIG. 6  is a rear perspective view of an ejector for a refuse vehicle, according to an exemplary embodiment; 
         FIG. 7  is a partial sectional view of the body of a refuse vehicle showing the ejector rails, according to an exemplary embodiment; and 
         FIG. 8  is a detail sectional view of the ejector received in a rail of the body for a refuse vehicle, according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Before turning to the figures, which illustrate the exemplary embodiments in detail, it should be understood that the present application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting. 
     The total weight of a refuse vehicle is regulated by local, state, or federal agencies defining a maximum gross vehicle weight (e.g., a maximum gross weight for a vehicle on certain roadways). Weight savings derived from the construction of the refuse vehicle thereby allows for a corresponding increase in the cargo capacity (e.g., as measured in terms of weight) of the vehicle. According to an exemplary embodiment, a refuse vehicle includes an ejector and a corresponding ejector track designed to reduce the magnitude of stresses carried by a body assembly of the vehicle. Reducing the magnitude of stresses carried by a body assembly of the vehicle reduces the requisite thickness of material, amount of bracing, and number of other structural supports, which reduces the weight of the ejector and body assembly and increases the cargo-capacity of the refuse vehicle. 
     Referring to  FIGS. 1-2 , a vehicle, shown as refuse truck  10  (e.g., garbage truck, waste collection truck, sanitation truck, etc.), includes a chassis, shown as a frame  12 , and a body assembly, shown as body  14 , coupled to frame  12 . As shown in  FIGS. 1-2 , refuse truck  10  also includes a cab  15  coupled to a front end of frame  12 . Cab  15  includes various components to facilitate operation of refuse truck  10  by an operator (e.g., a seat, a steering wheel, hydraulic controls, etc.). Refuse truck  10  further includes a prime mover  16  coupled to frame  12  at a position beneath cab  15 . Prime mover  16  provides power to a plurality of motive members, shown as wheels  18 , and to other systems of the vehicle (e.g., a pneumatic system, a hydraulic system, etc.). Prime mover  16  may be configured to utilize a variety of fuels (e.g., gasoline, diesel, bio-diesel, ethanol, natural gas, etc.), according to various exemplary embodiments. According to an alternative embodiment, prime mover  16  is one or more electric motors coupled to frame  12 . The electric motors may consume electrical power from an on-board storage device (e.g., batteries, ultra-capacitors, etc.), from an on-board generator (e.g., an internal combustion engine), or from an external power source (e.g., overhead power lines) and provide power to the systems of the refuse truck  10 . 
     According to an exemplary embodiment, refuse truck  10  is configured to transport refuse from various waste receptacles within a municipality to a storage or processing facility (e.g., a landfill, an incineration facility, a recycling facility, etc.). As shown in  FIGS. 1-2 , body  14  includes panels  22 , a tailgate  28 , and a cover  29 . Panels  22 , tailgate  28 , and cover  29  define a collection chamber, shown as a compartment  20 . Loose refuse is placed into compartment  20  where it may be thereafter compacted. Compartment  20  provides temporary storage for refuse during transport to a waste disposal site or a recycling facility. In some embodiments, at least a portion of body  14  and compartment  20  extend in front of cab  15 . According to the embodiment shown in  FIGS. 1-2 , body  14  and compartment  20  are positioned behind cab  15 . In some embodiments, compartment  20  includes a hopper portion and a storage portion. Refuse is initially loaded into the hopper portion and thereafter compacted into the storage portion. According to an exemplary embodiment, the hopper portion is positioned between the storage portion and cab  15  (i.e. refuse is loaded into a position behind cab  15  and stored in a position further toward the rear of refuse truck  10 ). 
     Referring again to the exemplary embodiment shown in  FIG. 1 , refuse truck  10  is a front-loading refuse vehicle. As shown in  FIG. 1 , refuse truck  10  includes a pair of arms  24  coupled to frame  12  on either side of cab  15 . Arms  24  may be rotatably coupled to frame  12  with a pivot (e.g., a lug, a shaft, etc.). In some embodiments, actuators (e.g., hydraulic cylinders, etc.) are coupled to frame  12  and arms  24 , and extension of the actuators rotates arms  24  about an axis extending through the pivot. According to an exemplary embodiment, interface members, shown as forks  25 , are coupled to arms  24 . Forks  25  have a generally rectangular cross-sectional shape and are configured to engage a refuse container (e.g., protrude through apertures within the refuse container, etc.). During operation of refuse truck  10 , forks  25  are positioned to engage the refuse container (e.g., refuse truck  10  is driven into position until forks  25  protrude through the apertures within the refuse container). As shown in  FIG. 1 , arms  24  are rotated to lift the refuse container over cab  15 . A second actuator (e.g., a hydraulic cylinder) articulates forks  25  to tip the refuse out of the container and into the hopper portion of compartment  20  through an opening in cover  29 . The actuator thereafter rotates arms  24  to return the empty refuse container to the ground. According to an exemplary embodiment, a top door  30  is slid along cover  29  to seal the opening thereby preventing refuse from escaping compartment  20  (e.g., due to wind, etc.). 
     Referring to the exemplary embodiment shown in  FIG. 2 , refuse truck  10  may be a side-loading refuse vehicle that includes a grabber  34  configured to interface with (e.g., engage, wrap around, etc.) a refuse container (e.g., a residential garbage can, etc.). According to the exemplary embodiment shown in  FIG. 2 , grabber  34  is movably coupled to body  14  with an arm  36 . Arm  36  includes a first end coupled to body  14  and a second end coupled to grabber  34 . An actuator (e.g., a hydraulic cylinder) articulates arm  36  and positions grabber  34  to interface with the refuse container. Arm  36  may be moveable within one or more directions (e.g., up and down, left and right, in and out, rotation, etc.) to facilitate positioning grabber  34  to interface with the refuse container. According to an alternative embodiment, grabber  34  is movably coupled to body  14  with a track. After interfacing with the refuse container, grabber  34  is lifted up the track (e.g., with a cable, with a hydraulic cylinder, with a rotational actuator, etc.). The track may include a curved portion at an upper portion of body  14  such that grabber  34  and the refuse container are tipped toward the hopper portion of compartment  20 . In either embodiment, grabber  34  and the refuse container are otherwise tipped toward the hopper portion of compartment  20  (e.g., with an actuator, etc.). As grabber  34  is tipped, refuse falls through an opening in cover  29  and into the hopper portion of compartment  20 . Arm  36  or the track then returns the empty refuse container to the ground, and top door  30  may be slid along cover  29  to seal the opening thereby preventing refuse from escaping compartment  20  (e.g., due to wind). 
     Referring next to  FIG. 3 , a compactor, shown as packer system  40  (e.g., press, compactor, packer, etc.), is positioned within compartment  20 . According to an exemplary embodiment, packer system  40  is configured to compact the refuse within the hopper portion of compartment  20  into the storage portion of compartment  20  thereby increasing the carrying capacity of the refuse truck  10 . In some embodiments, packer system  40  utilizes hydraulic power to compact the refuse from the hopper portion into the storage portion. As shown in  FIG. 3 , packer system  40  includes a ram, shown as ejector  42 , and actuators, shown as hydraulic cylinders  44 . Hydraulic cylinders  44  are coupled to ejector  42  and a frame member of body  14 , shown as head wall  46 . Head wall  46  is positioned along the cab of the refuse vehicle, according to an exemplary embodiment. According to an exemplary embodiment, the head wall  46  is a lightweight structure that includes an end wall  52  coupled to a pair of side gussets  54  at a pair of corners. Side gussets  54  couple end wall  52  with various lower frame members of body  14 . 
     As shown in  FIG. 3 , hydraulic cylinders  44  are positioned to extend ejector  42  rearward away from head wall  46 . In some embodiments, hydraulic cylinders  44  each include a first end coupled to one of the corners formed by end wall  52  and side gusset  54  and a second end coupled to ejector  42 . According to an exemplary embodiment, hydraulic cylinders  44  extend diagonally such that the first end is coupled to end wall  52  at a first lateral side of body  14  and the second end is coupled to an opposite lateral side of ejector  42 . The first end may be coupled to end wall  52  with a first pivoting bracket and the second end may be coupled to the ejector with a second pivoting bracket. According to an alternative embodiment, packer system  40  includes hydraulic cylinders  44  that extend longitudinally along a length of body  14 . According to still other embodiments, packer system  40  includes a single actuator or another device to slide ejector  42  within compartment  20 . 
     Referring next to  FIG. 4 , the ram slides along a first track, shown as first rail  50 , and a second track, shown as second rail  50 . In some embodiments, first rail  50  and second rail  50  are integrally formed with body  14 . In other embodiments, first rail  50  and second rail  50  are formed as sub-components and thereafter coupled (e.g., welded, bolted, etc.) to the other components of body  14 . As shown in  FIG. 4 , first and second rails  50  extend along the length of compartment  20 . According to an exemplary embodiment, body  14  includes a plurality of panels. In some embodiments, body  14  is shaped as a generally rectangular box having two transverse upper edges, two longitudinal upper edges, two transverse lower edges, and two longitudinal lower edges. The longitudinal edges extend along the length of body  14  (e.g., the longer dimension, along the longitudinal direction, along an axis extending parallel to frame  12 , etc.) and the transverse edges extend across the length of body  14 . According to the exemplary embodiment shown in  FIG. 4 , rails  50  extend along lower longitudinal edges of body  14 . 
     Refuse is compacted from the hopper portion of compartment  20  to the storage portion of compartment  20  with a compacting stroke. During the compacting stroke, the ram (e.g., ejector  42 ) slides within compartment  20  on rails  50  along a longitudinal direction  60 . As shown in  FIG. 4 , longitudinal direction  60  is parallel to the longitudinal direction of body  14 . After the compacting stroke, the ram retracts by sliding within compartment  20  on rails  50  along a direction opposite longitudinal direction  60 . Extension of the actuators forces the ram away from a front end of body  14 , according to an exemplary embodiment. Such extension forces the ram against the refuse in the compartment  20 , which compresses the refuse against a portion of body  14  (e.g., an inner surface of a panel, a tailgate, etc.). According to an exemplary embodiment, packer system  40  compacts the refuse towards the back of the compartment  20  (e.g., the end of body  14  opposite the cab) against the tailgate  28  (e.g., for a front-loading or side-loading truck). According to an alternative embodiment, the actuators are positioned such that the compactor forces refuse towards the front of compartment  20  and against a head wall (e.g., for a rear-loading truck). According to other exemplary embodiments, the compactor includes other components (e.g., a screw mechanism) configured to otherwise process (e.g., compact, shred, etc.) the refuse within compartment  20 . 
     According to an exemplary embodiment, body  14  is rotatably coupled to the chassis of the refuse vehicle. An actuator may tip body  14  to empty refuse from the compartment  20  into another receptacle or collection area. According to an exemplary embodiment, body  14  is tipped backwards (e.g., the front end wall is lifted) with a hydraulic actuator (e.g., lift cylinders, dump cylinders, raise cylinders, etc.) to facilitate such an emptying operation. The tailgate may also be rotated with an actuator to expose the rear portion of compartment  20 . According to an alternative embodiment, body  14  remains stationary, and the tailgate is lifted such that a rearward motion of the ram pushes refuse out from the compartment  20 . 
     Referring again to the exemplary embodiment shown in  FIG. 4 , body  14  includes a floor  26  extending between rails  50 . As shown in  FIG. 4 , floor  26  is concave and curves downward. According to an exemplary embodiment, floor  26  has a radius of curvature of between approximately 100 and 250 inches. In one embodiment, the floor  26  has a radius of curvature of 114 inches. The weight of body  14  having floor  26  is less than the weight of a traditional body assembly. Floor  26  provides a weight reduction in part due to the high strength-to-weight ratio of floor  26  relative to a traditional flat floor. The increased strength-to-weight ratio allows for the use of fewer lateral sub-frame members (e.g., cross members) and smaller longitudinal sub-frame members (e.g., ribs, rails, etc.), which decreases the overall weight of the body  14  without decreasing the refuse-carrying capabilities of refuse truck  10 . The curvature reduces the peak stresses on floor  26  and reduces the displacement of cantilevered portions of floor  26  during loading. According to an exemplary embodiment, floor  26  is curved in both the hopper portion and in the storage portion of compartment  20 . In some embodiments, floor  26  is curved along the entire length of body  14 . 
     Referring next to the exemplary embodiment shown in  FIGS. 5-6 , ejector  42  is a hollow, lightweight structure designed to reduce the weight of a refuse vehicle. According to an exemplary embodiment, ejector  42  includes a plurality of assembled plates. Such plates may be metal (e.g., steel, aluminum, etc.), a polymeric material, or a composite material, among other alternatives. As shown in  FIGS. 5-6 , ejector  42  comprises a plurality of steel plates welded together. In other embodiments, ejector  42  is manufactured according to a different process (e.g., a cast assembly, plates bolted or otherwise coupled together, etc.). 
     As shown in  FIGS. 5-6 , the plates of ejector  42  define a plurality of surfaces. According to an exemplary embodiment, ejector  42  defines a packing face  62 . When positioned in a refuse vehicle, packing face  62  extends within a plane that is orthogonal to the longitudinal direction of the body assembly. Ejector  42  further defines an angled face  64  that is angularly offset from packing face  62  (e.g., oriented at an angle of between 20 and 60 degrees relative to packing face  62 ). As shown in  FIG. 5 , ejector  42  also defines an upper front face  66  and a top shelf  68 . A pair of side plates  70  extend along the longitudinal direction of the body assembly within planes that are perpendicular to packing face  62 , according to an exemplary embodiment. As shown in  FIG. 6 , the pair of side plates  70  are laterally spaced apart from one another, the distance therebetween defining a side plate spacing. 
     With ejector  42  in a retracted position (e.g., in a position toward the front of the body assembly), refuse emptied into the hopper portion of the collection chamber contacts angled face  64 , upper front face  66 , and top shelf  68 . The refuse thereafter falls into the collection chamber of the body assembly. Extension of hydraulic cylinders  44  slides ejector  42  rearward such that packing face  62 , angled face  64 , and upper front face  66  compress the refuse within the collection chamber. As shown in  FIGS. 5-6 , packing face  62  has a lower edge  63  shaped to correspond with the shape of a floor within the body assembly of the refuse vehicle. Lower edge  63  reduces the amount of refuse that migrates behind ejector  42  during extension and refraction of hydraulic cylinders  44 . According to an exemplary embodiment, ejector  42  further includes a frame  72 , braces  74 , and ribs  76 . As shown in  FIG. 6 , frame  72 , braces  74 , and ribs  76  are positioned to transfer loading between (i.e. tie together, support, facilitate interaction between, etc.) the various plates of ejector  42  (e.g., the plates that define packing face  62 , angled face  64 , upper front face  66 , top shelf  68 , and side plates  70 ). According to an exemplary embodiment, frame  72 , braces  74 , and ribs  76  include a plurality of openings intended to reduce the weight of ejector  42 . 
     According to an exemplary embodiment, ejector  42  further includes shoes, shown as projections  80 . As shown in  FIGS. 5-6 , projections  80  extend laterally outward from side plates  70 . According to an exemplary embodiment, projections  80  are positioned at a lower end of side plates  70  (e.g., the end of side plates  70  along lower edge  63 ). In some embodiments, projections  80  extend along the entire thickness of ejector  42 . In other embodiments, ejector  42  includes multiple projections  80  coupled to each side plate  70  (e.g., a pair of projections  80  on each lateral side of ejector  42 ). 
     Referring next to  FIG. 7 , projections  80  are received into rails  50  such that ejector  42  may slide within the collection chamber of the body assembly (e.g., for compaction of the refuse, for retracting ejector  42 , etc.). Compaction of refuse imparts various forces and moments on ejector  42 . By way of example, twisting moments may occur about a first vertical axis  82 , a second vertical axis  84 , or a third vertical axis  86 . While first vertical axis  82 , second vertical axis  84 , and third vertical axis  86  have been specifically described, twisting moments may occur about still other axes. Compaction may also impart tipping moments on ejector  42 , which may occur about lateral axis  88 . While lateral axis  88  has been specifically described, tipping moments may occur about still other axes. 
     Refuse may be unevenly distributed within the collection chamber of the body assembly (e.g., due to loading from only one lateral side of the refuse truck). By way of example, a first lateral side of the collection chamber may have refuse therein whereas a second lateral side of the collection chamber may be relatively free of refuse. Uneven distribution of the refuse may also occur due to the composition of the refuse whereby a first lateral side of the collection chamber includes stiff materials (e.g., metal products, plastic products, etc.) and a second lateral side of the collection chamber includes pliable materials (e.g., paper products, etc.). Extension of the actuators applies compaction forces to the first and second lateral sides of ejector  42 . The application of such compaction forces to unevenly distributed refuse causes a twisting moment about at least one of first vertical axis  82 , second vertical axis  84 , and third vertical axis  86  (e.g., relatively dense refuse on the side of ejector  42  at second vertical axis  84  may cause a twisting moment about second vertical axis  84 ). 
     Refuse may be similarly unevenly distributed vertically within the collection chamber of the body assembly. By way of example, such uneven distribution may occur as denser refuse settles to the bottom of the collection chamber (e.g., as the refuse vehicle moves). Extension of the actuators applies compaction forces to ejector  42  at a fixed vertical position (e.g., where the actuators are coupled to ejector  42 ). An uneven distribution of refuse produces a tipping moment about a horizontal axis (e.g., lateral axis  88 ). 
     Such forces and moments are transferred through projections  80  into rails  50  and the body assembly of the refuse vehicle. According to an exemplary embodiment, the combination of projections  80  and rails  50  is intended to maintain linear movement of ejector  42  (e.g., prevent ejector  42  from tipping over). The actuators coupled to ejector  42  may impart large forces to compact the refuse positioned within the collection chamber. Such large forces produce large twisting and tipping moments, which are carried by projections  80  and rails  50 . 
     Referring next to the detail view to  FIG. 8 , one projection  80  of ejector  42  is shown, according to an exemplary embodiment. As shown in  FIG. 8 , projection  80  is received into rail  50 . According to an exemplary embodiment, rail  50  is an angled channel structure and includes a lower wall  90 , an upper wall  92 , and a sidewall  94  extending between lower wall  90  and upper wall  92 . As shown in  FIG. 8 , upper wall  92  is laterally offset from lower wall  90  (e.g., upper wall  92  is positioned further from a centerline of ejector  42  than lower wall  90 ). In some embodiments, sidewall  94  is angularly offset from lower wall  90 . As shown in  FIG. 8 , sidewall  94  is offset at an acute angle, shown as angle θ, relative to the horizontally positioned lower wall  90 . In some embodiments, angle θ is between 45 and 75 degrees. According to an exemplary embodiment, angle θ is approximately 60 degrees. 
     Rail  50  is manufactured (e.g., bent from a sheet of material) such that sidewall  94  is coupled to lower wall  90  with a first arcuate portion  93  and coupled to upper wall  92  with a second arcuate portion  95 , according to an exemplary embodiment. As shown in  FIG. 8 , first arcuate portion  93  and the second arcuate portion have a radius of approximately one inch. Rail  50  reduces the weight of ejector  42  and the body assembly of the refuse vehicle. By way of example, angling sidewall  94  reduces the cross-sectional length of lower wall  90 , upper wall  92 , and sidewall  94  relative to an ejector track having a lower wall  90  extending laterally outward until sidewall  94  is positioned vertically (i.e. rail  50  is lower-weight than traditional “C” channel designs). 
     Referring again to the detail view shown in  FIG. 8 , projection  80  nests within rail  50  to facilitate relative movement between ejector  42  and the body assembly of the refuse vehicle. According to an exemplary embodiment, projection  80  includes a lower wall  100 , an upper wall  102 , and an angled sidewall  104  coupling the lower wall  100  to the upper wall  102 . As shown in  FIG. 8 , interface members, shown as wear pads, are positioned between projection  80  and rail  50 . Such interface members reduce the friction forces opposing the movement of ejector  42  and reduce the risk of damage to projection  80  (e.g., by providing replaceable contact surfaces). According to an exemplary embodiment, a lower wear pad  96  is coupled to lower wall  90  and an upper wear pad  98  is coupled to upper wall  92 , a lower wear pad  106  is coupled to lower wall  100  of projection  80  and an upper wear pad  108  is coupled to upper wall  92  of projection  80 , and a pair of angled wear pads  110  are positioned between sidewall  94  and sidewall  104 . Lower wear pad  96  interfaces with lower wear pad  106 , upper wear pad  98  interfaces with upper wear pad  108 , and angled wear pads  110  interface with one another during operation of ejector  42  (e.g., compaction, retraction, etc.). In other embodiments, a single wear pad is positioned between lower wall  90  and lower wall  100 , upper wall  92  and upper wall  102 , and sidewall  94  and sidewall  104  (i.e. a single wear pad may replace separate wear pads). The single wear pad may be coupled to one wall and interface with (e.g., slide along) the other, corresponding wall. 
     According to an exemplary embodiment, a centerline of lower wear pad  96  and lower wear pad  106  defines a central axis  112 . While central axis  112  is shown in  FIG. 8  as a line, central axis  112  may extend along the length of lower wear pad  96  and lower wear pad  106  thereby defining a central plane. As shown in  FIG. 8 , the centerlines of both lower wear pad  96  and lower wear pad  106  are positioned along the same central axis  112 . In other embodiments, lower wear pad  96  may be offset from lower wear pad  106  (e.g., positioned laterally inward and closer to a centerline of ejector  42 , etc.). As shown in  FIG. 8 , a centerline of upper wear pad  98  and upper wear pad  108  defines a central axis  114 . While central axis  114  is shown in  FIG. 8  as a line, central axis  114  may extend along the length of upper wear pad  98  and upper wear pad  108  thereby defining a central plane. As shown in  FIG. 8 , the centerlines of both upper wear pad  98  and upper wear pad  108  are positioned along the same central axis  114 . In other embodiments, upper wear pad  98  may be offset from upper wear pad  108  (e.g., positioned laterally inward and closer to a centerline of ejector  42 , etc.). 
     As shown in  FIG. 8 , an inner edge  120  of lower wall  90  is positioned laterally inward from central axis  112  (e.g., relative to a centerline of ejector  42 ), and an inner edge  122  of upper wall  92  is also positioned laterally inward from central axis  114 . Inner edge  120  of lower wall  90  is positioned laterally inward relative to inner edge  122  of upper wall  92 . According to an exemplary embodiment, inner edge  120  is positioned such that lower wall  90  provides a surface to which lower wear pad  96  is coupled. Inner edge  122  is positioned to facilitate movement of (e.g., not interfere with) ejector  42 . 
     According to an exemplary embodiment, the interface members are replaceable and provide bearing surfaces to allow ejector  42  to slide along rails  50  without direct contact between the metal structures of ejector  42  and rails  50 . In other embodiments, ejector  42  may slide directly upon rails  50 . In still other embodiments, a different mechanism facilitates movement between ejector  42  and rails  50  (e.g., rollers, low-friction surfaces, etc.). According to an exemplary embodiment, the interface members are manufactured from a material with a high wear resistance and a low coefficient of friction. According to an exemplary embodiment, the interface members are manufactured from a polymeric material (e.g., nylon). In one embodiment, the interface members are manufactured from self-lubricating nylon polymers (e.g., Nylatron®, etc.). The interface members are removably coupled to projections  80  and to rails  50  such that they may be replaced as they wear (e.g., coupled with bolts, rivets, etc.). 
     In some embodiments, a plurality of discrete interface members are provided along the length of rails  50  and projections  80 . The interface members may be dimensioned and spaced to maintain contact between the interface members on projection  80  and those on rails  50  as ejector  42  moves along the length of the rails  50 . According to other exemplary embodiments, the interface members on projections  80  and rails  50  are continuous strips. As shown in  FIG. 8 , the interface members (e.g., lower wear pad  96 ) include multiple individual pads stacked together. Such stacking allows for an increased thickness and increased life for the interface members. The thickness of the stack of individual pads may be selected to reduce movement of ejector  42  relative to rails  50  (e.g., twisting, tipping). In other embodiments, a single interface member (i.e. not a stack) is positioned between rail  50  and ejector  42 . The thickness of the single interface member may be selected to reduce movement of ejector  42  relative to rails  50 . 
     Extension of the actuators forces ejector  42  into the refuse within the collection chamber. Uneven loading of the refuse within the collection chamber may produce twisting moments and tipping moments on ejector  42 . Such twisting and tipping moments are resisted by contact between lower wear pad  96 , upper wear pad  98 , and angled wear pad  110  with lower wear pad  106 , upper wear pad  108 , and the second angled wear pad  110 , respectively. Such twisting and tipping moments may cause asymmetrical loading on the interface members. By way of example, a forward tipping moment (e.g., where an upper end of ejector  42  is tipped toward the cab of the refuse vehicle) drives the rearward end of projection  80  upward into rail  50  and drives the forward end of projection  80  downward into rail  50 . Such forces may be conveyed between projection  80  and rails  50  through the interface members, according to an exemplary embodiment. 
     Referring again to  FIG. 8 , lower wear pad  96  and lower wear pad  106  are positioned below side plates  70  of ejector  42 . In some embodiments, central axis  112  is laterally aligned with side plates  70  of ejector  42 . According to another exemplary embodiment, central axis  112  is slightly offset from side plates  70  (e.g., where side plates  70  are laterally aligned with at least a portion of the interface members). Vertical forces on the ejector  42  (e.g., from a tipping moment, due to the weight of ejector  42 , due to the force from refuse contacting the faces of ejector  42  during loading, etc.) are transmitted through the side plates  70 . Ejector  42  and rails  50  transmit such vertical forces from side plates  70  directly downward into rails  50  through lower wear pad  106  and lower wear pad  96 . Ejector  42  and rails  50  avoid cantilevered loading and corresponding bending stresses resulting therefrom. According to one embodiment, the total stresses imparted on ejector  42  and rails  50  during operation of the compactor, the requisite thicknesses of material and number of structural supports, and the weight of the refuse vehicle are reduced. 
     Uneven loading between the two lateral sides of ejector  42  (e.g., due to an uneven distribution of refuse in the collection chamber, due to an uneven composition of refuse in the compartment  20 , due to an uneven pressure applied by the hydraulic cylinders  44 , etc.) produces a twisting moment on ejector  42 . Twisting moments are resisted by the contact between the angled wear pads  110  and the upper wear pad  98  with the upper wear pad  108 . Angling sidewalls  94  and sidewalls  104  centers ejector  42  within the collection chamber (e.g., laterally centers, etc.) thereby reducing the risk of unevenly wearing angled wear pads  110 , upper wear pads  98 , and upper wear pads  108 . 
     The construction of the body assembly and compactor is intended to reduce the overall weight of the refuse vehicle, thereby allowing for an increase in the maximum refuse carrying capacity without exceeding gross vehicle weight regulations imposed on some roadways. A reduced number of components simplifies fixture designs and increases the ease of manufacturing. Support below the side plates of the ejector instead of in a cantilevered position allows for the direct transfer of vertical loads into the frame of the vehicle thereby reducing stresses on the ejector and the body. 
     The construction and arrangements of the refuse vehicle, as shown in the various exemplary embodiments, are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. Some elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process, logical algorithm, or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes, and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.