US 3556324 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
United States Patent Inventor John McCarthy Dearborn, Mich.
Appl. No. 748,857
Filed July 30, 1968 a Division of Ser. No. 516,603, Dec. 27, 1965,
Patent No. 3,410,427.
Patented Jan. 19,1971
Assignee Gar Wood Industries, Inc. a corporation of Michigan REFUSE PACKING SYSTEM AND METHOD 5 Claims, 7 Drawing Figs.
US. Cl 214/152 Int. Cl B651 3/00 Field of Search 214/833,
 References Cited UNITED STATES PATENTS 3,049,256 8/1962 Urban 214/518 3,220,586 11/1965 Gollnick 214/833 3,257,012 6/1966 Berolzheimer 214/83.3X
Primary Examiner-Albert J. Makay Attorney--Harness, Dickey & Pierce ABSTRACT: A refuse packing and storage system in which successive batches of refuse are packed against a longitudinally movable panel within the refuse storage compartment, and wherein movement of the panel in a direction to increase the size of the storage compartment is permitted in response to packing forces.
PATENTEDJANISIHTI 3.556324 SHEET 1 0F 2 INVENTOR.
. 1 REFUSE PACKING SYSTEM AND METHOD This application is a divisional of application Ser. No. 5l6,603 filed Dec. 27, i965, now U .S.. Pat. No. 3,4l0.427, and is directed to the method disclosed in thatprior application. i
The present invention relates generally to refuse packing and storage systems, and more particularly to those including a refuse storage compartment havingmeans located at one end thereof for loading the loose refuse and for then compact- For the first several charges compacted by the compaction panel against the ejector panel, full designed compaction will be obtained and the ejector panel will be released to move forwardly and increase the area of the storage compartment to the rear thereof because the force received on its rear face caused by the compaction panel and transmitted through the relatively small amount of refuse will be greater than 0.9x
ing it as it transfersit .into the refuse storage compartment, as
well as the method of controllingfsuch compacting. The present system may be used in connection with either stationary or mobile equipment, but for purposes of present'description'will be described associated with a refuse carrying vehicle having loading and compacting means at its rearward end in the tail gate thereof.
Refuse vehicles having rear end or tail gate loading and compacting mechanisms are well known in the art, and the ob ject of using' such compacting mechanisms is'to increase the density of therefuse carried by the vehicle so thata maximum quantity of input refuse material may behandled by the vehiplace and unloaded, often a ratherlengthyand time-consuming trip. In stationary equipment the object is to increase storage capacity for a given size unit and thereby lengthen the duration between unloading operations.
Known compacting mechanism have for the most part in-' cluded one or more power operated swinging, sliding or reciprocating panels which push the refuse under force into the storage compartment of the unit. The presentinvention is shown embodied in a system having such a mechanism, specifically one including a pair of-swinging panels, butis not so limited. Such a system is shownin U.S.'lat.No. 2,879,906.
Certain of the more recent refuse-vehicles on the market have increased their compaction efficiency by providing a longitudinally moving panel in the storage compartment against which refuse is packed o'r'compacted'from thefirst' load until thestorage compartment isfilled,-and which also is used to eject the load in the vehicle when it is filled and ready for unloading. Such ejector panels, asthey are-often referred to, are positioned at the rear end of the storage compartment adjacent the coinpacting mechanism at the beginning of the packing cycle when the truck is empty. Refuse is loaded and compacted against this plate until some degree of fullness or density is reached, whereupon the ejector panel is moved forwardly a relatively small distance, either manually or automatically, to provide room for the loading and compaction of additional refuse. Consequently, each charge of material passing through the compacting mechanism is compacted either against the ejector panel or against earlier charges of the material'which have been previously compacted against such panel. Systems of this type, if properly controlled, can give greater compaction density than those which do not pack against such an ejector panel, and it is this ejector panel type system to which the present invention is directed.
As can be appreciated, the manner in which the forward movement of the ejector panel is controlled is a primary factor in the performance of the unit in'terrns of degree of compaction. One method by which this has been done is to providemeans for releasing the ejector panel, whereby it may then be forced forwardly by the expanding refuse and/or pushing force of the compaction mechanism, when a predetermined force is exerted on the rear face of the ejector panel. Such systems, whether they be mechanical or hydraulic, have several disadvantages. One such disadvantage arises from the fact that there is a substantial amount of friction between the refuse and the sides of the storage chamber'as the refuse is pushed forwardly therein by the compacting mechanism. The resulting difficulty may be best understood from the following example: Assume that the compacting panel is adapted to exert a compacting force of X pounds across the cross-sectional area of the storage compartment and that the ejector panel is adapted to be released upon the application against its rear cle before it must be driven to adurnp or other appropriate v pounds.'However, as the storage compartment becomes increasingly full the exertion of X pounds of force against the refuse by the compaction panel in a given cycle results in the exertion upon the rear face of the ejector panel of a force which is-substantially less than i X or even 0.9X pounds because a progressively increasing proportion of the force exertedby the compaction panel is absorbed or reacted against by frictional forces along the bottom, sides and top of the storage compartment, Consequently, as the storage compartment becomes fuller the amount of movement forwardly of the ejector panelbecomes less per compaction cycle, until eventually the compacting panel is unable to cause any further forward movement of the ejector panel and no additional refuse may be loaded without stalling thecompaction panel. In systems of this type, whether they be hydraulic or mechanical, this .point is often reached before the ejector panel is moved all the way to thefront end of the storage compartment, and consequently storage capacity is lost and the total amount of refuse which may be handled by the unit in one filling is reduced. This problem cannot really be avoided by setting the system so that it takes a much smaller force upon the rearface of the ejector panel to cause it to be released, because if this is done the degree of compaction from the very first load on is reduced proportionately andthe overall capacity of the unit is then reduced not because the entire storage chamber is not used but because there is a'lesser degree of compaction of the refuse material.
ln'such systems which are hydraulic and utilize telescopic cylinders for control of the ejector panel this problem is compounded because of thedifferential areas of the respective cylinders. For example. consider a system which is designed so that the ejector panel cylinder is permitted to dump to tank.
when the pressure therein created by forces .on the rearward face on the panel reaches a predetermined value. When the first loads are compacted in the unit the ejector panel is at the rear of the storage compartment and the telescopic cylinders fully extended, and the force on the rear face of the ejector panel necessary to cause this predetermined pressure in the ejector cylinder for release will be this predetermined pressure multiplied by the cross-sectional area of the rearmost and smallest cylinder of the telescopic cylinder assembly. As the storage compartment fills the larger cross-sectional area cylinders of the telescopic cylinder assembly come into use, and again the force necessary to cause the ejector panel to release will be the predetermined pressure in the ejector cylinders multiplied by the cross-sectional area of that stage thereof being actuated at that time. However, since this stage is necessarily larger in cross-sectional area than-the previous one, the force necessary to cause the panel to release is also larger. Consequently, the fuller the storage compartment the greater must be the force applied to the rear face of the ejector panel to cause it to release. In designing such a system it is therefore not possible to provide for the application of maximum compaction forces for the early stages of compaction, since as the compartment becomes filled there would be insufficient force available to even move the later larger diameter stages of the telescopic ejector cylinder. As a result, smaller initial compaction forces must be settled for, with the attendant loss of com paction efficiency. It can thus be seen that the aforementioned disadvantages of a system responsive to forces on the rear face of the ejector panel, are greatly amplified when a telescopic cylinder is used for the ejector cylinder.
The problems created by the aforementioned disadvantages are substantially further amplified as the size of the storage compartment is increased in volume and length. This is because larger and longer storage chambers require telescopic cylinder assemblies having a greater number of stages, and because the increased inside surface area of such chambers increases the friction forces resisting movement of the refuse forwardly in the chamber. Since the current trend is towards larger and longer storage units, these problems present design restrictions which are of increasing significance.
Systems which are manual in nature, wherein forward movement of the ejector panel is caused by the manipulation of manual controls, suffer the disadvantage that the efficiency of the system depends upon the ability of the operator to accurately gauge when the ejector panel should be moved forwardly, as well as the amount of movement when so moved, and generally speaking operators of equipment of this nature are relatively unskilled. Systems which provide for a releasing of the ejector panel at the completion of each compaction cycle, or at some other time period, suffer the disadvantage that during the period of time from the completion of one compaction cycle to the initiation of the next compaction cycle the natural expansion of the previously compressed refuse may cause the ejector panel to move forwardly a greater distance than is desired for an optimum degree of compaction. and consequently overall compaction efficiency is reduced.
It is therefore a primary object of the present invention to provide a system of the general type discussed above which is relatively simple in construction and method of operation, and which avoids the aforementioned disadvantages of other known systems, whereby maximum loading of a given storage compartment, both in terms of extent of filling and degree of compaction. may be obtained. It is a related object to provide such a system utilizing a hydraulically driven packing panel and an ejector panel actuated by a hydraulic telescopic cylinder assembly.
These and other objects of the present invention will become apparent from consideration of the specification taken in conjunction with the accompanying drawings in which there are illustrated two embodiments of the present invention, and wherein:
FIG. 1 is a side elevational view, partially broken away, showing the major portion of a refuse vehicle in which the present invention may be embodied;
FIGS. 2, 3, and 4 are similar to FIG. I but with substantial parts broken away to shown an operating cycle of the loading and compacting system of the vehicle;
FIG. 5 is a diagrammatic view showing a hydraulic control circuit for the system of FIGS. 1-4, embodying the principles of the present invention;
FIG. 6 is an enlarged sectional view of one of the valves forming a part of the circuit shown in FIG. 5', and
FIG. 7 is a diagrammatic view of a portion of the circuit shown in FIG. 5, illustrating a modification thereof.
The present invention may be embodied in many different types of refuse compacting systems, including both stationary and mobile systems, and those having single as well as double panels in the loading and compacting mechanism; however, for purposes of present illustration it is shown herein embodied in a refuse vehicle of the general type in US. Pat. No. 2,879,906. As can be seen, the unit comprises a conventional truck chassis 10 to which is secured a storage compartment 12 having at the rearward open end thereof a tail gate assembly 14 pivotally secured to the storage compartment, as by hinges 16, to enable it to be swung upwardly by a tail gate piston and cylinder assembly 18, secured at one end to the storage compartmeut and at the other end to the tail gate, when it is desired to unload the refuse compartment. Tail gate assembly 14 includes a lower cylindrical portion defining a trough into which refuse may be loaded, a rotating sweep panel 22 for sweeping the refuse out of trough 20 and bringing it to an elevation substantially in line with the bottom of the storage compartment, and a pivotally mounted ram panel 24 for moving the loaded refuse from the top of the sweep panel and compacting it into storage compartment 12. Sweep panel 22 may be powered by a rotary hydraulic motor 26 through a conventional sprocket and chain drive mechanism 28, and ram panel 24 may be powered by a hydraulic double acting piston and cylinder assembly 30 secured at one end to the tail gate assembly and at the opposite end to ram panel 24. Both sweep panel 22 and ram panel 24 extend substantially the full width of the storage compartment and tail gate assembly, and the latter extends substantially the 'full width of the storage compartment. 1
Inside the storage compartment there is provided an ejector panel 32 which has a cross-sectional area substantially the same as that of the storage compartment'and which is adapted to move forwardly and rearwardly longitudinally of the vehicle. Ejector panel 32 may be powered bya conventional double acting telescopic piston and cylinder assembly 34 secured at one end to the base of the ejector panel and at its opposite end to the forward wall of the storage compartment.
In FIG. 5 there is illustrated a representative hydraulic circuit for a refuse system such as shown in the preceding FIGS. It includes a tank or reservoir 36 for the hydraulic fluid, and a pump 38 the inlet of which is connected to tank 36 by a fluid supply line 40. The pump may be driven in the usual fashion by the vehicle engine. In a stationary system it could be electrically driven. The outlet of pump 38 is connected to a main control valve 42 by mcans of a fluid supply line 44. Control valve 42 is connected to rain cylinder 30 by means of a fluid supply line '46 (for packingstroke) and a fluid return line 48. to tail gate cylinder 18 by means ofa fluid supply line 50 and a fluid return line 52, to hydraulic sweep motor 26 by means of a fluid supply line 54 and a fluid supply line 56, and to telescopic ejector cylinder assembly 34 by means of a fluid supply line 58 (for ejection stroke) and a fluid return line 60. Control valve 42 is connected directly to tank 36 by means of a fluid return line 62. Control valve 42 which in the usual system comprises a plurality of valves, is provided with the usual actuating handles 64 for powering the ram cylinder, tail gate cylinder, sweep motor and telescopic ejector cylinder assembly, respectively, in the conventional manner. All of the circuit described up to this point is believed to be typical of known circuits and may be varied numerous ways by those skilled in the art to achieve the particular function desired since it is not per se a part of the present invention but only one representative circuit to which this invention is applicable.
The primary distinguishing feature of the subject circuit is the provision of a pilot operated dumping valve 65. This valve, which will be described in greater detail below, is connected by means of fluid line 66 to ejector cylinder supply line 58, by means of fluid line 68 to ram cylinder supply line 46, and by means of fluid line 70 to tank 36. This valve operates to permit the dumping to tank of fluid from the ejection stroke side of the ejector cylinder in response to and upon the reaching of a predetermined pressure in the power or packing stroke side of the ram cylinder.
As can be seen in FIG. 6, pilot operated dumping valve 65 comprises a body 72 having a valve bore 74 therein. Fluid line 66 communicates with valve bore 74 by means of a passageway 76, and fluid line 70 by means ofa passageway 78. Disposed within the bore 74 is a valve spool adapted to slide longitudinally therein from a first position in which communication between lines 66 and 70 is blocked (the position shown in FIG. 6) and a second position wherein line 66 is placed in communication with line 70 by means of a groove 81 in spool 80. Secured to one end of housing 72 is a cover structure 82 having a bore 84 therein in alignment with bore 74. Movement of valve spool 80 is caused on the one hand by means of a compression return spring 86 disposed within bore 84 and pushing against one end of spool 80, and on the other hand by means of a small piston 88 actuated by the pressure in fluid line 68 and engaging the opposite end of spool 80. Thus, as can be seen, the valve spool is normally maintained in the position shown in FIG. 6 wherein communication between lines 66 and 70 is blocked. However, upon the application of a predetermined amount of pressure to line 68, the force exerted on the spool in the downward directionQas shown in FIG. 6,.by small piston 88 will overcome the counteracting force exertedjby' return spring 86 and the valve spool will move downwardly to place fluid line 66 in communication with fluid line 70. Return spring 86 is preferably a low rate spring so that the valve will not operate as a metering valve in which the flow into fluidline 70 is to some extent proportional to the pressure in line 68. On the contrary, if it is desired that the valve operate as an on-off valve which ideally is fully off when the pressure in fluid line 68 is below a predetermined valve and which is fully on when such pressure is at or above this predetermined valve. The actual pressure at which the spool will shift may be varied somewhat by means of an'adjusting screw 90 which engages a stop member 92 supporting the lower end of return spring 86. Passageways 94 and 96 are provided in the spool and housing respectively to provide an escape for the normally encountered leakage.
The method of operation of the system is asfollows: In FIG. 2 the storage compartment is shown partially filled and the system in an at rest condition in which ram panel '24 is in its forwardmost position holding the refuse, indicated at 98, tightly against ejector panel 32, and in which the sweep panel has been rotated to a position clear of hopper so that the latter is ready to receive the next load of refuse. When the hopper has been filled the proper actuatingcontrol is operated and sweep panel 22 starts to rotate in a counterclockwise direction. As it clears ram panel 24 the latter starts moving rearwardly, and the sweep panel continues its counterclockwise rotational movement, engaging the refuse and sweeping it up towards the storage compartment: In FIG. 3 the system is shown justafter the sweep panel has engaged the refuse and is starting to. push it forwardly and upwardly. This movement of the'sweeppanel continues until the refuse is raised to a level substantially in line with the bottom of the storage compartment. at which time full-power is applied to the ram panel and it sweeps the refuse off the upper surface of sweep panel 22 and pushes it with maximum force into the storage compartment against ejector panel 32. FIG. 4 shows the system midway in this step of the cycle.
As will be appreciated, during'c'ompaction the pressure on the power side of ram cylinder 30, i.e., in fluid line 46, will be substantially. proportional to the compactingforces on the refuse in the storage compartment exerted by the'ram'panel. When this force, and hence ram cylinderpressure, reaches a predetermined value, the pressure in fluid line will cause pilot operated valve 65 to pop open and dump fluid from the power stroke side of ejector cylinder, whereupon the latter will be pushed forwardlyby the continued forward movement of ram panel 24. However, since the dumping of the ejector cylinder reduces the reactive forces acting against the ram panel, the pressure in the ram cylinder decreases and when it drops below the predetermined value valve 65 closes and further forward movement of the ejectorpanel is arrested. Control valve 42. will have no influence on this operation because the ejector cylinder is not being actuated. during the It has'been discovered that very good results are obtained when valve 65 isdesigned and adjusted so that it will open when the'pressure in the ram cylinder supply line'is approximately 80percent' of the maximum'pressure reached in that line, as determined by the usual relief valve. This figure of 80 percentprovides a consistently high degree of compaction and yet is sufficiently below the pressure setting of the relief valve (100 percent) that no fluid is likely todump across the relief valve. with the attendant losses in power and efficiency. as well as heating of the hydraulic fluid..ln other words. it has been found that a 20 percent safety factor will give excellent compaction without getting too close to the dumping pressure of the ram cylinder relief valve, which as1will be appreciated will vary somewhat in an actual production valve due to manu facturing'tolerances and hysteresis. It also accounts for any exert increasingly greater reactive forces asthe compartment becomes more filled. I
In the circuit shown in FIG. 5, fluid line 68 is shown connected to the supply line for the ram cylinder. This arrangement is preferable in systems where there is a possibility that one of the other hydraulic functions performed by the overall system will require the use of pressures in excess of the predetermined pressure setting of dumping valve 65 which might cause the dumping valve to dump fluid from the ejector cylinderduring some other cycle of the system, such as when I the ejector cylinder is being used to eject the load from the compaction cycle, and therefore fluid lines 58 and 60 will be 1 closed in the control valve, in the usual manner. In addition, any safety relief valve provided in the ejector cylinder circuit will be set at a pressure higher than any encountered during the compacting cycle, so that it also will not influence this operation.
It has been found that in actual operation of the present system the ejector panel tends to index forwardly insmall rapid increments. Since its movement is arrested whenever the ram cylinder pressure is below the predetermined value the refuse is substantially continually subjected to at least the compacting force created by the ram "panel under the influence of this predetermined pressure. This provides an advantage over systems which permit a complete releasing of the ejector panel after the ram panel has completed its packing stroke since in such systems the refuse is allowed to expand to g a lower degree of compaction, pushing the ejector panel further forwardly than desirable.
storage compartment, or when the tail gate is raised, or the like.
In systems where this is not likely to occur, it has been found that the line for control fluid to dumping valve 65 may be connected directly to the main supply. line from the pump. Such an arrangement is shown in FIG. 7,.wherein dumping valve- 65 is shown connected to fluid supply line 44 by means of fluid line 680. As can be seen, this FIG. is identical in all respects to FIG. 5, except'that the dumping valve is connected to supply line 44 rather than supply line 46, and therefore the same reference numbers are used. Since in many systems the maximum' pressure encountered, for all the hydraulic functions contemplated, is the pressure used to actuate the ram panel to compact the refuse into the storage compartment, a circuit of the type shown in FIG. 7 is often perfectly satisfactory.
When the storage compartment is full unloading is accomplished by raising the tail gate, using piston and cylinder assembly l8, and actuating ejector panel 32, which is in its forwardmost position when the compartment is filled, to cause it to move rearwardly to eject or push the refuse out of the compartment. In circuits of the type shown in FIG. 7 there is virtually no risk that the dumping valve will be opened by the supply of fluid under pressure to the ejector cylinder for ejecting the load, since it has been found that pressures required for this purpose are substantially below the pressures encountered in the ram cylinder during packing, as well as substantially below the predetermined pressure setting.
Thus there are disclosed in the above description and in the drawings several exemplary systems embodying the method of the present invention which fully andefiectively accomplish the objects thereof. However, it will be apparent that variations in the details thereof may be indulged in without departing from the sphere of the invention herein described, or the scope of the appended claims.
I. A method of compacting batches of refuse into a refuse storage compartment having an opening at one end, a first panel mounted therein for movement away from said one end and a packing panel for packing refuse into said compartment through said opening. comprising: holding the first panel against movement away from said one end; moving the packing panel to pack a batch of refuse into the compartment at said one end thereof against the first panel; sensing the packing force exerted by the packing panel on said batch of refuse; and releasing the first panel for movement away from said one end when said packing force reaches a predetermined value sufficient to provide the desired compaction. said predetermined value remaining substantially constant for all degrees of compartment filling.
2. The method as claimed in claim 1, wherein the first panel is released for movement away from said one end in progressive steps. one step each time said packing force reaches said predetermined valve.
3. The method as defined in claim lefurther including the step of reestablishing said holding step following the performance of said releasing step.
4. The method as defined in claim 1. further including repeating said holding. moving, sensing and releasing steps in a plurality ofcycles of said steps.
5. The method as claimed in claim 1. comprising the further step of moving the first panel toward said oneend to force packed refuse out of the storage compartment.