US3786946A

US3786946A - Refuse collection vehicles

Info

Publication number: US3786946A
Application number: US00227504A
Authority: US
Inventors: H Liberman; H Ratledge; C Toppins; S Harvey; S Voorhees
Original assignee: Dempster Brothers Inc
Current assignee: Dempster Systems Inc; Dempster Brothers Inc
Priority date: 1970-07-30
Filing date: 1972-02-18
Publication date: 1974-01-22
Anticipated expiration: 1991-01-22

Abstract

A rear loader for refuse collection vehicles. The rear loader includes a housing with an opening through which refuse is deposited in a hopper. A movable packer plate in the housing moves in opposition to the bottom of the hopper to partially compress the material and subsequently to convey the material through a discharge opening into the body of the vehicle. The packer plate in the housing also cooperates with an ejector plate in the body to further compress the refuse contained within the body.

Description

United States Patent [1 1 Toppins et a].

[ Jan. 22, 1974 REFUSE COLLECTION VEHICLES [75] Inventors: Charles R. Toppins; Samuel E.

Harvey; Harvey W. Liberman, all of Knoxville; Houston Ratledge, Maryville; Steven C. Voorhees, Oak Ridge, all of Tenn.

[73] Assignee: Dempster Brothers, Inc., Knoxville,

Tenn.

[22] Filed: Feb. 18, 1972 [21] Appl. No.: 227,504

Related US. Application Data [62] Division of Ser. No. 59,453, July 30, 1970, Pat, No.

[52] US. Cl. 214/152 [51] Int. Cl B65f 3/04 [58] Field of Search 2l4/83.3, 503, 152

[56] References Cited UNITED STATES PATENTS 3,653,522 4/1972 Gollnick 2l4/83.3

7/1969 Merther 214/83.3 l/l967 Paru et a1. 214/503 X Primary ExaminerFrank E. Werner Attorney, Agent, or FirmBurns, Doane, Swecker &

Mathis [5 7] ABSTRACT A rear loader for refuse collection vehicles. The rear loader includes a housing with an opening through which refuse is deposited in a hopper. A movable packer plate in the housing moves in opposition to the bottom of the hopper topartially compress the material and subsequently to convey the material through a discharge opening into the body of the vehicle. The packer plate in the housing also cooperates with an ejector plate in the body to further compress the refuse contained within the body.

8 Claims, 11 Drawing Figures PATENTEI] JAN22 1974 SHEET 1 OF 4 FIG. I

PATENTED JAN 2 21974 snmanra REFUSE COLLECTION VEHICLES This is a division, of application Ser. No. 59,453, filed July 30, 1970, now US. Pat. No. 3,696,951.

BACKGROUND OF THE INVENTION This invention relates to refuse collection vehicles and more particularly to apparatus for loading and packing refuse from the rear of a vehicle into the body of the vehicle.

Refuse collection trucks of the rear loader type are often used for collection of trash and other refuse in residential areas. Typically, a rear loader mechanism is provided on the tailgate of a truck having an enclosed body. Workmen collect refuse at each house in large containers and carry these containers to the truck where they are dumped into the hopper located in the tailgate assembly of the truck. The rear loader mechanism is usually operated by manual controls located adjacent the hopper opening. The operator causes the rear loader to run through a loading cycle each time the hopper has been filled. Some types of conventional rear loader mechanisms do not permit refuse to be dumped into the hopper during the loading cycle. Therefore, workmen may have to wait at the truck for a considerable length of time before emptying their containers and returning to pick up the next load.

The frequency of operation of the rear loader mechanism depends upon the capacity of the hopper. A large hopper can store temporarily a larger volume of refuse and accordingly less time is lost while waiting for the loading mechanism to complete its cycle. The height of the sill of the bottom of the tailgate opening is one factor that limits hopper capacity. The higher the refuse receiving opening is above the ground, the more effort is required by the workmen in dumping their containers into the hopper. Accordingly, the sill over which the refuse is dumped into the hopper should be as low as possible.

' Another problem encountered in using rear loaders for residential collection is that often relatively large objects are included in the refuse and the rear loader must be capable of handling these objects without jamming. Furthermore, the rear loader mechanism should effectively reduce the volume of refuse, so that the refuse can be packed into the interior of the truck body at a maximum density.

The controls of the rear loader should be easy to operate and permit the operator to stop'the mechanism at any point in the cycle and to repeat the cycle, if necessary. Some conventional rear loader mechanisms must run through the entire cycle before it can be repeated. This means that a longer time is required for the loading and packing operation.

SUMMARY OF THE INVENTION In view of the deficiencies of prior rear loader apparatus, it is an object of this invention to provide improved rear loader apparatus for refuse collection vehieles.

It is a further object of this invention to provide rear loader apparatus that is capable of receiving large objects without jamming.

Another object of this invention is to provide a rear loader apparatus that packs refuse material into the body of the vehicle at a high density.

A still further object of this invention is to provide rear loader apparatus that operates quickly with simple controls.

Theseobjects are accomplished in accordance with a preferred embodiment of the invention by rear loader apparatus including a housing with a refuse receiving opening at the rear and a discharge opening at the front side communicating with the interior of the vehicle body. A hopper is positioned in the bottom of the housing and has a support surface between the refuse receiving opening and the discharge opening. A panel extends across the housing and is supported on arms for swinging movement about a shaft. A packer plate is pivotally mounted on the panel for swinging about an axis parallel to the panel pivot axis. Power means moves the packer plate in opposition to the hopper surface to compress the refuse, and subsequently along the hopper surface to sweep the compressed refuse through the discharge opening into the vehicle body, where it is subjected to further compression.

DETAILED DESCRIPTION OF THE DRAWINGS Certain embodiments are illustrated in the accompanying drawings in which:

FIG. 1 is a side elevational view of a refuse collection vehicle incorporating the rear loader apparatus of this invention:

FIG. 2 is a rear elevational view of the vehicle in FIG.

FIG. 3 is a cross sectional view, partially schematic, along the line 3-3 in FIG. 2, showing in full lines the starting and the final position of the packer plate at the completion of the compaction step in the cycle, and showing in phantom lines the packer plate in a raised position;

FIG. 4 is a cross sectional view of the apparatus along the line 4-4 in FIG. 3;

FIG. 5 is a cross sectional view, partially schematic, of the rear loader apparatus, with the panel and packer plate in a raised position;

FIG. 6 is a cross sectional view, partially schematic, as in FIG. 5, but showing the panel and packer plate during the second phase of the cycle;

FIG. 7 is a cross sectional view, partially schematic, as in FIG. 5, but showing the panel and packer plate in the intermediate phase of the cycle;

FIG. 8 is a cross sectional view, partially schematic, as in FIG. 5, but showing the panel and packer plate during the final phase of the cycle;

FIG. 9 is a schematic view of the hydraulic circuit for operating the rear loader apparatus of this invention;

FIG. 10 is a detail cross sectional view of the hopper and packer plate as in FIG. 7, but showing the apparatus modified to include bag opening teeth; and

FIG. 11 is a section at right angles thereto on the line l1-11 in FIG. 10.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT A vehicle in which the rear loader apparatus of this invention is incorporated, is shown in FIGS. 1 and 2. The vehicle includes a chassis 2 on which a refuse body 4 is secured. The body 4 has opposite side walls 6 and a top wall 8, which are suitably braced to resist deflection due to the pressures exerted by the contents of the body 4.

An ejector plate is mounted in the interior of the body 4 for reciprocating movement between front and rear positions. The ejector plate 10 is shown in the rear position in FIG. 1. The ejector plate extends across the full width of the body 4 between the side walls 6 and between the top 8 and the bottom of the body 4. Thus, the ejector plate forms a movable front wall for the body 4. A telescoping hydraulic ram 12 extends between a bracket on the top 8 of the body and a bracket at the bottom of the ejector plate 10. Extension of the ram 12 displaces the ejector plate 10 toward the rear of the body 4, while retraction of the ram 12 displaces the ejector plate toward the front of the body.

A tailgate assembly 14 is mounted on hinges 16 at the rear of the body 4. The tailgate assembly 14 has side walls 18 and a top 20. The side walls 18 are spaced apart approximately the same distance as the side walls 6 of the body, so that the tailgate assembly 14 forms a closure for the rear end of the body 4. Latches 22 adjacent the bottom of the body 4 are provided on opposite sides of the tailgate assembly 14. These latches are preferably of the type having screw threads for drawing the tailgate assembly 14 firmly against the rear edge of the side walls 6 and the bottom of the body 4. A sealing strip 24 (FIG. 4) extends along the front edge of the side walls 18 and across the bottom edge of the tailgate assembly to prevent leakage between the edges of the tailgate assembly 14 and the body 4. By tightening the latches 22, the sealing strip is compressed to provide an effective seal.

A pair of hydraulic rams 26 are provided on opposite sides of the tailgate assembly 14. The rams 26 are attached at one end to a brace on the side wall 18 and at the opposite end to a bracket on the side wall 6 of the body. By releasing the latches 22 and extending the rams 26, the tailgate assembly 14 can be made to swing vertically about the hinges 16 for dumping the contents of the body 4 as the ejector plate 10 is displaced rearwardly.

The tailgate assembly 14 includes a transverse beam 28 and a transverse sill 30 extending between the side walls 18. The refusereceiving opening 32 at the rear of the tailgate assembly 14 is bounded by the beam 28, the sill 30 and the side walls 18. The assembly 14 also includes a front wall 34 (FIGS. 3 and 4) that extends downwardly from the top and across the width of the assembly between the side walls 18, and terminates in a transverse edge 36 along which a scraper bar 38 is attached. The edge 36 of the front wall 34 is spaced above the uppermost edge of the front surface 46 of the hopper 42 to define a discharge opening 41 between the interior of the tailgate assembly and the interior of the vehicle body at the rear of the ejector plate 10. The tip of the hopper projecting up within the body assists in holding trash inside the body. The scraper bar 38 mounted on the lower edge 36 of the front wall 34, projects rearwardly through the opening 41, as shown in FIG. 3.

A hopper 42 is provided in the bottom of the tailgate assembly 14. The hopper includes a rear support surface 44 and a front support surface 46. The

surfaces

44 and 46 extend across the width of the tailgate assembly transversely of the vehicle. The rear surface 44 is curved downwardly from the sill 30 and the front surface 46 is curved upwardly from the rear surface 44 to the bottom 40 of the body, where it terminates in an edge that projects through the opening 41.

A transverse shaft 48 is rigidly supported in brackets 49 that aresuspended from the beam 28 adjacent each side wall 18. Arms 50 are pivotally mounted on shafts 48 adjacent the opposite sides of the hopper 42. A rigid panel 52 extends between the side walls 18 and is supported at opposite ends on the arms 50. The panel 52 has a curved forward surface preferably formed by a curved metal plate 53 secured upon a skeleton frame 53'. A brace 54 extends between each arm 50 and the upper edge of the panel, as shown in FIG. 3. Another brace 54' is secured between each arm 50 and the panel 52 adjacent the lower edge thereof. Thus, the panel 52 is fixed relative to the arms 50 and swings in an are about the shafts 48. The scraper plate 38 is secured to a reinforcing bar on the lower edge of the wall 34 for wiping engagement with the plate 53.

The position of the panel 52 is controlled by a hydraulic ram 55 adjacent each arm 50. Each ram 55 is pivotally mounted at one end on the top wall 20 by a bracket 56, as shown schematically in FIG. 3.-A shaft 58 is mounted at the lower edge of the panel 52 adjacent each end of the panel. The end of the piston rod of each ram 55 is pivotally secured on the respective shaft 58. Extension of the pistons in the rams 55 causes the panel 52 to swing downwardly from the position shown in full lines in FIG. 3 to the position shown in FIG. 7. i

A packer plate 60 extends across the tailgate assembly 14 between the side walls 18 and is mounted on a skeleton frame 62 that is suspended for swinging movement on the respective shafts 58. The central axis of the shafts 58 about which the plate 60 and frame 62 swing relative to the panel 52 is parallel to the axis of the shafts 48. The cylinder end of a hydraulic ram 64 is pivotally mounted on the shaft 48 between each arm 50 and the adjacent side wall 18. The piston rod of each ram 64 is pivotally secured to the supporting frame 62 of the plate 60 by a pin 66. Retraction of the pistons in the rams 64 swings the plate 60 upwardly from the position shown in full lines to the position shown in phantom lines in FIG. 3.

Movement of the panel 52 and the packer plate 60 is controlled by the hydraulic circuit shown schematically in FIG. 9. The principal control is a lever operated spool valve 68 having a neutral position 8 at the center, a cross flow position A at the right end of the spool and a straight flow position C at the left end of the spool. A control handle 70 for operating the spool valve 68 is positioned on the side wall 18 (FIG. 2). When the panel 52 and the plate 60 are in the positions shown in FIG. 3, and the spool valve 68 is positioned as shown in FIG. 9, hydraulic fluid does not flow to either pair of

cylinders

55 and 64, and the panel 52 and the packer plate 60 remain stationary. With the panel and pcaker plate in the positions shown in full lines in FIG. 3, the packer plate 60 may be raised by retracting the piston rods in the rams 64.

A limit switch 72 is mounted under the top wall 20 and has a lever in position to open the switch when the panel is raised to the position shown in FIG. 3. Another limit switch 74 is mounted on the panel brace 54'. A lever on the switch 74 is in position to be engaged by a projection 76 fixed on the frame 62. The switch 74 is open when the lever is engaged by the projection 76. A third limit switch 78 is normally open, but is in position to be closed when the handle 70 is displaced to align position C with the inlet and outlet ports for the valve. The limit switches 7 2, 74 and 78 are connected in parallel circuit with each other. A control valve 80 has a spool that is operated by a solenoid 82. When the solenoid 82 is energized, the cross flow position of the valve is aligned with the inlet and outlet ports. When the solenoid 82 is deenergized, a spring returns the spool to the position shown in FIG. 9. The solenoid 82 is connected with a source of electrical current through the

switches

72, 74 and 78, so that if any one of the switches is closed, the solonoid is energized.

Fluid under pressure is supplied by a pump 83 from a tank 84. The fluid flows through a conduit 86 to a manually controlled valve 88 which is normally positioned as shown in FIG. 9 to conduct fluid under pressure to the control valve 68. A solenoid on the engine of the vehicle is connected with the limit switches 72, 74 and 78 so as to advance the throttle when any one of the solenoids is closed to move the spool of the valve 88 to the open position shown in FIG. 9.

Assuming that the packer plate 60 and panel 52 are in the positions shown in full lines in FIG. 3, the cycle is started by moving the handle 70 to displace the straight flow position C of the valve 68 into alignment with the inlet and outlet ports of the valve. This movement of the valve spool closes the limit switch 78, thereby energizing the solenoid 82 to align the cross flow position of the spool with the ports in the valve 80. Hydraulic fluid is conducted under pressure through the conduit 90 to displace the spool of a two-position valve 92 toward the right as viewed in FIG. 9 to align the straight flow section of the spool with the inlet and outlet ports.

Fluid under pressure passes through the conduit 94 and through the valve 92 and a conduit 98 to the end of a three-position spool valve 96. The valve 96 is shown in the neutral position B in which fluid from the pump 83 ,is returned to the tank 84. Fluid flowing through the conduit 98 displaces the spool valve 96 toward the right as viewed in FIG. 9 to align the position A with the inlet and outlet ports thereby conducting fluid under pressure through the conduit 100 to the rod ends of the rams 64. Fluid is exhausted from the head ends of the rams 64 through a conduit 102 and through the valve 96 to the tank 84. In this condition, the piston rods of the rams 64 pull the packer plate 60 upwardly from the position shown in full lines in FIG. 3 to the position shown in FIG. 5. As soon as the plate 60 swings sufficiently to close the limit switch 74, this switch maintains the solenoid 82 energized and the handle 70 can be released.

Fluid flowing through the conduit 100 to the rod end of the rams 64 is tapped through a conduit 104 which communicates with the end of a spool valve 106 to displace the straight flow section of the spool into alignment with the inlet and outlet ports, as shown in FIG. 9. As soon as the packer rams 64 begin to retract the packer plate, the operating handle 70 can be released to allow the springs to return the spool to the center position, as shown in FIG. 9. Fluid flowing through the valve 92 to the conduit 98 maintains the valve 96 at the cross flow position and the pistons inthe rams 64 continue to retract.

When the packer plate 60 has retracted to the position shown in phantom lines in FIG. 3, the frame 62 engages stops 107 mounted on the side walls 18. As a result, the pressure in the conduit 100 increases sufficiently to open an adjustable relief valve 108 which allows fluid to flow under pressure through the conduit 110 to the valve 92, thereby displacing the spool of the valve toward the left (FIG. 9) until the cross flow portion of the valve is aligned with the inlet and outlet ports. This causes fluid under pressure to be conducted through the conduit 112 and through the valve to the valve 96, resulting in the spool of the valve 96 being displaced toward the left until the straight flow section C of the valve spool is aligned with the inlet and outlet ports. I

Fluid is then conducted under pressure through the conduit 102 to the head end of the packer rams 64, causing the packer plate 60 to swing downwardly toward the position shown in FIG. 6. At the same time, fluid pressure in the conduit 102 opens the pilot pressure operated check valve 114, so that as the pistons in the ram cylinders 64 move outwardly, fluid is exhausted from the rod end and passes through the valve 114 and through the conduit 116 to the conduit 118 which is connected with the head ends of the panel rams 55. As the pistons in the rams 55 extend, fluid exhausted through the rod ends passes into the conduit 120, but the flow to the valve 96 through the conduit 120 is blocked by a check valve 122. Pressure in the conduit 118 opens the valve 124, thereby allowing fluid to flow from the conduit 120 through the conduit 118 to the head ends of the panel rams 55.

The differential area beween the head ends and rod ends of the pistons in the rams 55 creates a pressure differential which causes fluid to flow through the valve 124 to the panel cylinders 55. Since the head ends of the rams 55 is receiving fluid from the rod ends of both the packer rams 64 and the panel rams 55, it is not necessary to pump fluid from the valve 96 to the rams 55. All of the fluid from the pump 83 is conducted to the packer rams 64. Thus, this system permits the use of a smaller pump without a corresponding decrease in the rate of movement of the packer plate 60 and panel 52.

Both the panel 52 and the packer plate 60 swing downwardly in a coordinated manner along the path shown in FIG. 5 until the free edge of the plate 60 has moved from the position A to the position B. In moving toward the position B, the panel 52 and the plate 60 pass through the position shown in FIG. 6, where it can be seen that refuse in the hopper 42 is compressed between the contoured bottom surfaces 44 and 46 and the descending plate 60 and panel 52.

When the pistons in the rams 55 reach the end of their stroke, movement of the panel 52 stops. Fluid pressure in the conduits and 116 is sufficient to overcome the bias of the relief valve 128 to allow the valve to open and conduct fluid at a predetermined pressure from the rod end of the packer rams 64 to the tank 84. The pressure required to open the valve 128 is adjusted to provide a selected packing force exerted by the plate 60 against the

surfaces

44 and 46. Fluid under pressure continues to flow through the conduit 102 to the head end of the packer cylinders 64, thereby causing the free edge of the packer plate 60 to swing through a circular path about the pins 58, as indicated by the path from B to C in FIG. 5. The surface of the hopper 42 is curved to correspond to the path of the free edge of the packer plate as it sweeps along the surface 44 of the hopper. The packer plate 60 is shown in FIG. 7 during its sweeping motion along the surface 44. The location of the hinge pins 58 during this motion causes material to be compressed against the surface 46 as it is conveyed toward the discharge opening 41. If the material in the hopper 42 prevents the packer .plate from swinging downwardly, a check valve 128 inlet and outlet ports. Fluid is then conducted through the conduit 136 to open the pilot operated unloading valve 138, thereby allowing fluid from the head end of the cylinders 55 to flow through the valve 138 to the tank 84.

As soon as the fluid pressure at the head end of the pistons inthe rams 55 decreases, the valve 124 closes and the flow from the valve 96 opens the check valve 122 to conduct fluid under pressure to flow to the rod end of the rams 55. At the same time, fluid flows to the head end of the packer rams 64 through the conduit 102 to maintain a predetermined high pressure on the pistons in the rams 64 to urge the packer plate downwardly when the plates reaches a position spaced from the curved front support surface 44 of the hopper. The surface 46 is substantially concentric with the shafts 48, and as the packer plate is carried upwardly by the panel 52, the free edge of the packer plate sweeps along the surface of the hopper 42, as shown schematically by the path C-D in FIG. 5. The final forward position D of the plate 60 is shown in full lines in FIG. 3.

When the panel 52 reaches the position shown in full lines in FIG. 3, the limit switches 72 and 74 are opened by the panel 52 and by the projections 76 on the frame 62. The opening of these switches deenergizes the solenoid 82, thereby allowing the spring to displace the valve spool to of the valve 80 align the straight flow section with the inlet and outlet ports of the valve. Thus, fluid at both ends of the spool in the valve 96 is at tank pressure and the opposing springs cause the valve spool to be centered, thereby shutting off flow of fluid to both the panel cylinders and the packer cylinders. Movement of the panel and packer, therefore, stops and fluid is recirculated through the control valve 96 to the tank 84. A safety relief valve 140 is also included in the supply circuit.

The movement of the panel 52 and packer plate 60 can be stopped at any position of the cycle by lifting an operating lever 142 (FIG. 2) which is adjacent the main lever 70. The lever 142 is connected with the spool of the valve 88, which automatically equalizes the pressure at opposite ends of the spool in the valve 96 to shut off flow of fluid to the panel and packer cylinders. Furthermore, when the valve 88 is in the position shown in FIG. 9, by operating the lever 70 to shift the spool of the valve 68 from one extreme position to the other, the extending movement of the pistons in the panel cylinders 55 followed by retracting movement of the pistons in the panel cylinders can be repeated while the panel 52 is over the support surface 46 (FIG. 7) to agitate the refuse material between the curved surface 53 of the panel and the surface 46. This action tends to break up agglomerated material that otherwise might interfere with compacting in the vehicle body. Similarly, downward movement of the packer plate can be repeated to crush articles in the hopper against the

surfaces

44 and 46.

In the event that the refuse in the hopper is so resistant to compression that motion of the packer plate stops, fluid continues to flow to the head ends of the rams 64, but since the refuse prevents movement of the pistons in the rams 64, the relief valve 132 opens, causing the panel rams to swing the panel 52 away from the hopper surface, while maintaining the packer plate at its relative position when its swinging motion is stopped. Thus, the edge of the plate rakes across the refuse in the hopper toward the discharge opening 41 and the cycle can be repeated until the refuse is crushed to a volume small enough to press through the discharge opening. An important feature of the hydraulic system is that the packer plate continues through its cycle even though the refuse is not reduced to its minimum volume. The entire cycle, or portions of the cycle, can be repeated as necessary, and jamming does not occur.

In operation, the packer plate and panel are initially held stationary in the positions shown in full lines in FIG. 3, and refuse is dumped over the sill 30 into the hopper 42. Upon lifting the handle 70, the packer plate swings away from the opening 41 until it reaches the position shown in FIG. 5. In this position, it is spaced above the refuse in the hopper. The compaction of refuse within the body 4 of the vehicle is usually sufficient to keep most of the material from falling rearwardly through the opening 41.

After the panel and packer plate reach the positions shown in FIG. 5, the rams 5S and 64 extend simultaneously causing the panel 52 to be displaced downwardly, while the packer plate 60 swings downwardly and this coordinated movement causes the edge of the plate 60 to move along the path A-B in FIG. 5. Any objects in the hopper 42 that project into the path of the packer plate are compressed against the hopper surfaces 44 and 46, as shown in FIG. 6. Also, the curved surface 53 of the panel 52 cooperates with the hopper surface 46 to agitate material in the hopper, thereby reducing the column effect and improving subsequent compaction within the body of the vehicle.

When the packer plate reaches the position B shown in FIG. 5, further downward movement of the panel 52 stops. The packer plate 60 then swings downwardly, further compressing the refuse in the hopper and when the packer plate reaches the position shown in FIG. 7, the panel begins to swing upwardly carrying with it the packer plate which conveys the compressed refuse from the hopper 42 through the discharge opening 41 into the body of the vehicle. The packer plate 60 works in opposition to the ejector head 10 to compress the refuse within the body. The ejector head 10 progressively moves forwardly in the vehicle body to provide increased capacity for the refuse as successive batches of refuse are packed into the body.

The rear loader apparatus of this invention can be conveniently operated by means of the handle and if large objects of refuse are deposited in the hopper 42, the packer plate 60 can be recycled as necessary to reduce the volume of the refuse to a size that will pass through the discharge opening 41, without having to repeat the entire cycle. The crushing action between the packer plate and the bottom of the hopper 42 is sufficient to crush articles of furniture and small appliances, and other bulky articles usually encountered in residential collections.

The shape of the hopper 42 provides a large capacity immediately adjacent the sill 30 of the refuse receiving opening 32. This allows the workmen to dump their containers easily into the hopper without the problem of the hopper overflowing and littering the streets. The panel 52 also swings in opposition to the curved surface 46 of the hopper. This action tends to break up compacted refuse that otherwise might produce a column effect within the vehicle body.

Since the hydraulic fluid from the discharge side of the

respective rams

55 and 64 is conducted back to the pressure side of the rams 55, fluid is conserved and the rams are capable of moving the panel and packer plate at a greater rate than otherwise would be possible with a pump of the same capacity. This reduces the overall cost of the rear loader and provides an efficient operating cycle.

Refuse is sometimes set out along the route of the loader, in disposable bags of paper or plastic. Plastic bags of refuse can be compacted in the loader, if there is sufficient opening to allow escape of the entrapped air. Paper bags have greater tensile strength and present more of a packing problem unless the bags are opened.

lf opening of the bags, either paper or plastic, is desirable, means may be provided in the hopper for opening the bags as the latter are moved through the hopper toward the opening. In the embodiment shown in FIGS. 10 and 11, a hopper corresponding to the hopper 42 of FIG. 3 is illustrated, but the hopper of this embodiment has one or more rows of teeth 144 mounted on the bottom surface 46a of the hopper. These teeth may be sufficiently pointed or provided with sharpened edges to assure tearing open of the bags as they are moved by the packer plate 60a.

The packer plate 60a may extend in overlapping relation with the row of teeth 144, if desired. In that event, a notch 146 is provided for each row of teeth, as shown in FIG. 11, formed in the lower edge of the packer plate 60a.

Thus, upon operation of the packer plate 60 in the manner described above, the bags will be dragged over the row or rows of teeth 144 as shown in FIG. 10, to tear open the bags and thereby allow the refuse to be compacted effectively in the body.

While the invention has been illustrated and described in certain embodiments, it is recognized that other variations and changes may be made therein without departing from the invention as set forth in the claims. I

What isclaimed is:

1. A method of loading and packing refuse into a vehicle body by means of a movable packer plate cooperating with a hopper surface located between a refuse receiving opening and a discharge opening communicating with the interior of the vehicle body comprising:

swinging said packer plate away from said discharge opening and away from said hopper surface about a first axis extending transversely of said hopper; swinging said packer plate in a circular path about a second axis spaced from said hopper surface a greater distance than said first axis while simultaneously swinging said plate about said first axis toward said hopper surface, and subsequently holding said first axis stationary adjacent said receiving opening while swinging said plate about said first axis, whereby refuse in said hopper is compressed between said packer plate and said hopper surface; and swinging said first axis about said second axis without rotating said packer plate about said first axis, 5 whereby said packer plate displaces refuse along said support surface toward said discharge openmg.

2. The method according to claim 1 wherein said packer plate has a transverse edge spaced from said first axis and said hopper surface is substantially circularadjacent said receiving opening and including:

swinging said packer plate about said second axis while said packer plate transverse edge sweeps along said hopper surface, a portion of said hopper surface being in opposition to said packer plate during said sweeping motion, whereby refuse material on said hopper surface is compressed between said packer plate and said hopper surface.

3. The method according to claim 2 wherein said swinging of said packer plate about said first axis toward said hopper surface continues until a predetermined force is applied to said plate in opposition to said swinging movement.

4. The method according to claim 2 including stopping motion of said packer plate relative to said hopper surface intermediate said receiving opening and said discharge opening, and swinging said packer plate and said panel away from said hopper support surface, and subsequently swinging said packer plate axis and said packer plate relative to said packer axis toward said hopper surface, whereby repeated compression of refuse in said hopper can be accomplished without repeating a complete cycle of the motion of the packer plate.

5. The method according to claim 1 wherein said rear loader includes a panel hinged to said packer plate along said packer axis, said panel including a tamping surface movable in opposition to said hopper surface and including swinging said tamping surface of said panel and said packer plate simultaneously toward said hopper surface, whereby refuse material on said surface is compressed between said tamping surface and said hopper surface to supplement the compression of said packer plate.

6. A method of loading and packing refuse into a vehicle body of the type having a hopper with a bottom surface extending from a refuse receiving opening to a discharge opening located between the hopper and the interior of the vehicle body, the method comprising:

positioning a packet plate in said hopper above and in opposition to said bottom surface and adjacent said discharge opening;

displacing said packer plate from adjacent said discharge opening to adjacent said receiving opening while maintaining said packer plate spaced above said bottom surface, the spacing between said plate and said bottom surface progressively decreasing while said plate is displaced toward said receiving opening so as to intially compress refuse between said plate and hopper;

swinging said packer plate about a pivot axis that is temporarily fixed relative to said hopper surface, said packer plate having an edge spaced from said axis and said edge sweeping along said hopper surface as said plate swings about said axis, and advancing said packer plate toward said discharge opening while progressively moving said pivot axis on said hopper surface may be compressed between said plate and said surface.

8. The method according to claim 6 wherein said displacing step includes moving said packer plate while maintaining said pivot axisa fixed distance from a second axis which is fixed in said hopper adjacent said receiving opening, said second axis being parallel to said pivot axis and said pivot axis moving in an arcuate path about said second axis during said displacing step.

Claims

1. A method of loading and packing refuse into a vehicle body by means of a movable packer plate cooperating with a hopper surface located between a refuse receiving opening and a discharge opening communicating with the interior of the vehicle body comprising: swinging said packer plate away from said discharge opening and away from said hopper surface about a first axis extending transversely of said hopper; swinging said packer plate in a circular path about a second axis spaced from said hopper surface a greater distance than said first axis while simultaneously swinging said plate about said first axis toward said hopper surface, and subsequently holding said first axis stationary adjacent said receiving opening while swinging said plate about said first axis, whereby refuse in said hopper is compressed between said packer plate and said hopper surface; and swinging said first axis about said second axis without rotating said packer plate about said first axis, whereby said packer plate displaces refuse along said support surface toward said discharge opening.

2. The method according to claim 1 wherein said packer plate has a transverse edge spaced from said first axis and said hopper surface is substantially circular adjacent said receiving opening and including: swinging said packer plate about said second axis while said packer plate transverse edge sweeps along said hopper surface, a portion of said hopper surface being in opposition to said packer plate during said sweeping motion, whereby refuse material on said hopper surface is compressed between said packer plate and said hopper surface.

6. A method of loading and packing refuse into a vehicle body of the type having a hopper with a bottom surface extending from a refuse receiving opening to a discharge opening located between the hopper and the interior of the vehicle body, the method comprising: positioning a packer plate in said hopper above and in opposition to said bottom surface and adjacent said discharge opening; displacing said packer plate from adjacent said discharge opening to adjacent said receiving opening while maintaining said packer plate spaced above said bottom surface, the spacing between said plate and said bottom surface progressively decreasing while said plate is displaced toward said receiving opening so as to intially compress refuse between said plate and hopper; swinging said packer plate about a pivot axis that is temporarily fixed relative to said hopper surface, said packer plate having an edge spaced from said axis and said edge sweeping along said hopper surface as said plate swings about said axis, and advancing said packer plate toward said discharge opening while progressively moving said pivot axis away from said hopper surface and simultaneously sweeping said edge along said hopper surface, whereby refuse in said hopper is compressed between said packer plate and said hopper surface.

7. The method according to claim 6 wherein said hopper includes a sill defining the bottom of said receiving opening, and wherein said edge is maintained spaced above said sill during said displacing step, said swinging step including swinging said plate from a position at which said edge is spaced above said sill to a position spaced below said sill, whereby refuse material on said hopper surface may be compressed between said plate and said surface.

8. The method according to claim 6 wherein said displacing step includes moving said packer plate while maintaining said pivot axis a fixed distance from a second axis which is fixed in said hopper adjacent said receiving opening, said second axis being parallel to said pivot axis and said pivot axis moving in an arcuate path about said second axis during said displacing step.