Patent ID: 12202668

DESCRIPTION OF AT LEAST ONE EMBODIMENT

In the following description, the terms ‘first’, ‘second’, ‘extracting’, ‘retracting’, and so on, are used only to separate similar features or refer to directions relative to the hydraulic cylinder3of the compression apparatus1or its constructional details as they are shown in the attached figures.

FIGS.1to3illustrate an embodiment of a compression apparatus1for compressing refuse into a collection bin at different stages of a compression cycle. Figures further4to8illustrate configurations of two embodiments of the invention at different stages of the compression cycle. In these embodiments, the compression cycle of the compression apparatus1comprises three main phases: a first extracting phase, a second extracting phase, and a retracting phase. In the first extracting phase the refuse either gives low resistance or no resistance to the compression apparatus1. In the second extracting phase the refuse gives a high resistance to the compression apparatus1. In the retracting phase the refuse gives no resistance to the compression apparatus1. Therefore, the load profile changes throughout the compression cycle, and different aspects of the compression apparatus1are valued differently at different phases. In the first extraction phase the compression tool2moves from its starting position towards its end position until it meets the refuse, and the compressed refuse begins to resist the movement of the compression tool2. When the resistance raises above a predetermined threshold, the compression apparatus1moves to the second extracting phase. In this second extracting phase the compression apparatus1exerts more force on the refuse thus completing the compression. Once all refuse is compressed into the bin and the compression tool2has reached its end position, the compression apparatus1moves to its final retraction phase wherein the compression tool2is retracted to its starting position. The load profiles of these 3 phases vary such that the first extracting phase requires least force production from the hydraulic cylinder3and the second extracting phase requires most force production from the hydraulic cylinder3.

In the embodiment ofFIGS.1to3, the compression apparatus1comprises a compression tool2having a first end2aand a second end2b, wherein the first end2aof the compression tool2is pivotably hinged in the compression apparatus1, and rotation of the second end2bof the compression tool2is actuated by a hydraulic cylinder3. The compression apparatus1may comprise more than one parallel hydraulic cylinder3for actuating the compression tool2, for instance two hydraulic cylinders, such that the hydraulic cylinders are positioned on each side of the compression tool2.

In the embodiment ofFIGS.1to3, the compression tool2comprises a pivoting lever2c, which extends from the first end2aof the compression tool2and in a direction substantially perpendicular to the second end2bof the compression tool2. This configuration allows the compression tool2to compress the refuse into the refuse collection bin when the hydraulic cylinder3is extracting, and respectively to retract when the hydraulic cylinder3retracts. A pivoting lever2cshorter than the distance between the first end2aand the second end2bof the compression tool2also allows the second end2bof the compression tool2to travel a longer distance than the hydraulic cylinder3, thus speeding up the compression cycle. However, other pivoting configurations with differing levers and contact points may also be utilized in connecting the hydraulic cylinder3to the compression tool2.

In the embodiment ofFIGS.1to3, as illustrated inFIGS.4to7, the hydraulic cylinder3comprises three separate chambers31,32,33, such that a first extracting chamber31and a second extracting chamber32are arranged on extracting side of the hydraulic cylinder3, and a retracting chamber33is arranged on retracting side of the hydraulic cylinder3. These extracting and retracting sides are separated by a piston which is moved by supplying said hydraulic chambers with pressurized hydraulic fluid. The first extracting chamber31and the second extracting chamber32are configured to be utilized separately or jointly. Preferably, the first extracting chamber31and the second extracting chamber32are configured to be utilized separately or jointly depending on load on the compression tool2. This allows the working area of the hydraulic cylinder3on the extracting side to be fully or only partially utilized during the compression cycle, thus better matching the load profile of refuse compression cycle. In this way the use of force and hydraulic fluid is optimized, and maximum output of the hydraulic cylinder2is only used when it is needed. This has the benefit of better efficiency and cost savings.

In the embodiment ofFIGS.1to3, as illustrated inFIGS.4to7, the first extracting chamber31has a working area, which is smaller than a working area of the second extracting chamber32. This difference in working area allows the chambers to produce different forces and to move the piston at different speeds without altering output of the pump5. In the embodiment illustrated inFIGS.4to7, the second extracting chamber32cannot be pressurized separately due to the valve configuration. However, with a different valve configuration also the second extracting chamber32could be pressurized separately, thus creating 3 different force and speed profiles on the extracting side with same pump conditions.

In the embodiment ofFIGS.1to3, as illustrated inFIGS.4to7, the retracting chamber33has a working area, which is greater than the working area of the first extracting chamber31, and smaller than the working area of the first extracting chamber31and the working area of the second extracting chamber32combined. This is preferable due to as the compression tool2retracts, there is no load caused by compressing refuse making the forces required to retract the compressing tool2to be lower. Consequently, the working area of the retracting chamber33may be dimensioned smaller. Further, the retracting chamber33has a working area, which is greater than the working area of the first extracting chamber31, and smaller than the working area of the second extracting chamber32. This configuration further lowers the working area of the retracting chamber33, which results in needing a smaller volume of the hydraulic fluid to be supplied for the piston of the hydraulic cylinder3to travel the same distance, thus speeding up the retracting phase of the compression cycle.

In the embodiment ofFIGS.1to3as illustrated inFIGS.4to7, the compression apparatus1further comprises a first pressure sensor6afor determining the load on the compression tool2. This first pressure sensor6aallows the compression apparatus1to detect when the compression tool2meets the refuse to be compressed and to monitor pressure as the load begins to increase on the compression tool2.

FIG.4illustrates the hydraulic scheme of the first embodiment at rest, wherein the position of the compression apparatus1is locked, and all the chambers of the hydraulic cylinder3are closed. The first valve4ais in a such position that it does not allow the hydraulic fluid to move. This allows that the position of the compression apparatus1can be set and locked, which is important for worker safety.

FIG.5illustrates the hydraulic scheme of the first embodiment in first extracting phase of the compression cycle, wherein the compression tool2is under a load that is below a predetermined threshold load. In the first extracting phase the first valve4ais in such a position that the first valve4aallows the pump5to pressurize only the extraction side of the hydraulic cylinder3, such that the second valve4bblocks the pump5from pressurizing the second extracting chamber32, and thus only the first extracting chamber31is pressurized. The second valve4bconnects the second extracting chamber32with the hydraulic fluid tank8, such that hydraulic fluid may flow into the second extracting chamber32as the first extracting chamber31extracts the piston of the hydraulic cylinder3. Respectively, the first valve4aconnects the retraction chamber to the hydraulic fluid tank8such that the hydraulic fluid pushed out of the retracting chamber33is returned to the hydraulic fluid tank8. In other words, the compression apparatus1comprises one or more valves4, and the compression apparatus1is configured to control the valves4to supply only the first extracting chamber31with hydraulic fluid by a pump5. This allows the hydraulic cylinder3to utilize only the first extracting chamber31, which in turn allows the first extraction phase of the compression cycle to be completed faster and with a lower hydraulic fluid volume.

FIG.6illustrates the hydraulic scheme of the first embodiment in second extracting phase of the compression cycle, wherein the compression tool2is under a load above a predetermined threshold load. In the second extracting phase the first valve4ais in such a position that the first valve4aallows the pump5to pressurize only the extraction side of the hydraulic cylinder3, such that the second valve4ballows the pump5to pressurize both the first extracting chamber31and the second extraction chamber. Respectively, the first valve4aconnects the retraction chamber to the hydraulic fluid tank8such that the hydraulic fluid pushed out of the retracting chamber33is returned to the hydraulic fluid tank8, In other words, when the load is above a predetermined threshold, the compression apparatus1is configured to control the valves4to supply both the first extracting chamber31and the second extracting chamber32with hydraulic fluid by the pump5, This allows the hydraulic cylinder3to utilize both first extracting chamber31and second extracting chamber32to produce maximum force and to complete the second extracting phase of the compression cycle. This is advantageous as this sequence which requires more hydraulic fluid is only utilized when it is needed.

FIG.7illustrates the hydraulic scheme of the first embodiment in retracting phase of the compression cycle. In the retracting phase the first valve4ais in such a position that the first valve4aallows the pump5to pressurize both the extraction side and the retraction side of the hydraulic cylinder3, such that second extracting chamber32is shut off by the second valve4b. The first valve4aalso allows the hydraulic fluid to be circulated between the extraction side and the retraction side of the hydraulic cylinder3, As the working area of the retraction chamber is greater than the working area of the first extracting chamber31, the hydraulic fluid is pushed out of the first extracting chamber31and circulated into the retracting chamber33. In other words, the compression apparatus1is configured to control the valves4to supply both the retracting chamber33and the first extracting chamber31with hydraulic fluid by the pump5. This allows a retracting area to be combined with an extracting area in order to produce a small net retracting cylinder area, which requires a very small flow to operate, thus resulting in savings. However, the retracting phase can also be done without the recirculation such that the hydraulic fluid pushed out of the first extracting chamber31is returned to the hydraulic fluid tank8. In that case, the compression apparatus1is configured to control the valves4to supply only the retracting chamber33with hydraulic fluid by the pump5.

In the embodiment ofFIGS.4to7, the first valve4ais a directional valve having 3 positions and 4 ports, and the second valve4bis a directional valve having 2 positions and 3 ports. Further the first valve4ais spring centered having return springs on both sides of the valve, particularly the first valve4ais a closed center valve, and thus the hydraulic cylinder3can be stopped mid-stroke. This is advantageous for refuse compression, as it is an important safety measure to be able to stop the movement mid-stroke. Further, both valves4in this embodiment are electrical solenoid controlled directional valves, wherein the solenoid control can be used to offset the default position set by the springs. However, also other suitable valve configurations may be used to achieve the same functionality of the invention.

In the second embodiment illustrated inFIG.8, the compression apparatus1further comprises a hydraulic accumulator, which in this embodiment is formed as a closed hydraulic fluid tank7connected to the second extracting chamber32through the second valve4b. When the second valve4bis in a second position and the hydraulic cylinder3is retracted, the hydraulic fluid from the second extracting chamber32is pushed to the closed tank7creating pressure in the closed tank7. This pressure is stored by moving the second valve4bto its first position and the pressure can be released by moving the second valve4bto its second position. This is especially advantageous in the first extraction phase, when only the first extracting chamber31is pressurized with the pump5. This stored pressure allows the hydraulic fluid to easily flow into the second extracting chamber32, so it does not restrict the use of the hydraulic cylinder3. Further, this stored pressure in the closed tank7is used to prevent the second extracting chamber from cavitating. However, also other common configurations for hydraulic accumulators may be used.

Further, the second embodiment illustrated inFIG.8comprises a second pressure sensor6band a relief valve9for releasing the pressure. This relief valve9allows the compression apparatus1to release the pressure into the hydraulic fluid tank8, if the pressure increases over a set threshold pressure. This allows the hydraulic circuit to be protected from too high pressure. Additionally, the compression apparatus1further comprises a shut-off valve10, which is closed during normal use of the compression apparatus1but may be opened to release pressure or to empty the closed tank7. This is beneficial for activities that require the circuit to be free of pressure, such as when performing maintenance tasks on the compression apparatus1.

FIG.9illustrates a flow chart of an embodiment of a method for operating a compression apparatus, the method comprising: A actuating a compression tool with a hydraulic cylinder by supplying hydraulic fluid to a first extracting chamber of the hydraulic cylinder, B monitoring pressure to determine a load on the compression tool, C triggering step D only if the load is above a predetermined threshold, D supplying hydraulic fluid to a second extracting chamber of the hydraulic cylinder upon detecting a load on the compression tool if the load is higher than a predetermined threshold load, and E supplying hydraulic fluid to a retracting chamber of the hydraulic cylinder in order to retract the hydraulic cylinder.

Further, in the method step (E) the hydraulic fluid may be supplied both to the retracting chamber and the first extracting chamber of the hydraulic cylinder in order to retract the hydraulic cylinder. By supplying both the retracting chamber and the first extracting chamber with hydraulic fluid, a small net retracting area is used for retracting the hydraulic cylinder, requiring a very small flow to operate.

Preferably, the compression apparatus1is arranged in a refuse collection vehicle for compressing refuse collected from refuse containers on a refuse collection route.

Preferably, the pump5is a fixed displacement pump or a variable pump.

Preferably, the compression apparatus1comprises a controller, which may be implemented by circuits, or combination of circuits and software, such as a processor running a software stored in a memory.

It is to be understood that the above description and the accompanying figures are only intended to illustrate the present invention. It will be obvious to a person skilled in the art that the invention can be varied and modified without departing from the scope of the invention.