Patent Application
20140116040
This application claims the benefit of German Application DE 102012021544.4, filed Oct. 29, 2012, the contents of which are incorporated herein by reference thereto.
The present invention relates to a telescopic unit for telescoping means arranged on machines, comprising at least one telescopic hydraulic cylinder and at least one piston arranged as axially movable in the cylinder chamber of the telescopic hydraulic cylinder and connected to a piston rod, the bottom side or the piston rod side of the telescopic hydraulic cylinder being arranged as fixable on a bearing allocated to the machine, and at least one further hydraulic system being arranged on the free end of the telescopic unit which is energized with hydraulic energy via a hydraulic medium.
When machine parts are telescopically connected to one another and these parts are telescoped by means of a telescopic hydraulic cylinder, a hose routing (flange, barrel, etc.), a separate hydraulic system or a hydraulic cylinder with an internal oil connection has to be installed in order to allow for a further function at the exposed end of the telescopic hydraulic cylinder.
In order for a mobile crane with a telescopic boom, for example, to lift large loads with a small counterweight, the boom should be as small as possible. Particularly in the case of large working radii, the weight of the parts of the boom protruding beyond the support base should be kept as small as possible. It is also more advantageous if a lowest possible dead weight has to be moved when a mobile crane is transported.
As a result, single-cylinder telescopic units with a securing and bolting unit—hereinafter designated as SVE—are in most cases installed in such mobile cranes. With this system, a telescopic box is secured to the telescopic hydraulic cylinder by means of the SVE and subsequently unbolted from the surrounding telescopic box. Now, the telescopic hydraulic cylinder extends to the desired length with the telescopic box and bolts the telescopic boxes to one another and unlocks the telescopic hydraulic cylinder from the just moved telescopic box. This procedure is repeated until all telescopic boxes of a telescopic boom have reached their working position. In order to reduce the torque on the boom-side the telescopic hydraulic cylinder is again completely retracted to an initial position. Only now can the extended boom be loaded with a maximum weight.
In these systems, the SVE is located at the exposed end of the telescopic hydraulic cylinder. The hydraulic energy is consequently also required at this point in order to unlock or lock the boxes. In this respect, the disadvantage is that precisely this point is moved back and forth with the telescopic hydraulic cylinder. As a result, the SVE is not directly accessible to hydraulic lines.
At least two approaches to ensure the oil supply, and thus the supply with hydraulic energy, are known from prior art.
Hydraulic hoses routed parallel to the telescopic hydraulic cylinder by means of an energy chain.
In this case, the disadvantage is that the ducts for routing these hydraulic hoses require a lot of space, which is not available, in particular, in smaller telescopic boxes.
A telescopable hydraulic line, which is routed directly through the telescopic hydraulic cylinder in order to route the hydraulic oil to the SVE.
Guiding the oil flow in this way saves space, but also has the disadvantage that such an arrangement is expensive and prone to disruption (the pressure transmission in the penetration tube leads to problems). In case of damage, it can only be remedied with considerable time and concomitant financial expenditure. The entire telescopic hydraulic cylinder has to be removed and dismantled for repairs.
It is therefore an object of the present invention to provide a telescopic unit of the kind described above, with which the above disadvantages can be overcome.
In one embodiment, this object is attained by adjusting the piston in the telescopic hydraulic cylinder, the hydraulic energy, which is [generated] by changing the operating status and the resulting difference in the hydraulic pressure of the hydraulic medium, is diverted to and stored in at least a first intermediate reservoir, so as, in this way, to energize the hydraulic system allocated to the free end of the telescopic unit with the hydraulic energy from the first intermediate reservoir, if necessary, and wherein, after consumption of the hydraulic energy stored in the hydraulic medium, the hydraulic medium of the hydraulic system is routed to at least a second intermediate reservoir, and from there again into the telescopic hydraulic cylinder, where it is again energized with hydraulic energy or conveyed to the primary hydraulic circuit of the telescopic unit.
According to an advantageous embodiment of the telescopic unit according to the present invention, the first intermediate reservoir is automatically loaded with the hydraulic medium as soon as the pressure of the hydraulic medium in the telescopic hydraulic cylinder is higher than the pressure of the hydraulic medium in the first intermediate reservoir.
According to another advantageous embodiment, the hydraulic medium is automatically unloaded from the second intermediate reservoir as soon as the pressure of the hydraulic medium in the telescopic hydraulic cylinder is lower than the pressure of the hydraulic medium in the second intermediate reservoir.
It is further provided that the pressures in the intermediate reservoirs are measured with pressure sensors and that the measured pressure data is processed by a computer or sent directly to a control unit.
By way of example, high and low pressures occur in the hydraulic system in case of load changes. In this connection, the intermediate reservoirs act as storage tanks which temporarily store the high and low pressures in the hydraulic system. Depending on the design, the loading and unloading process of the intermediate reservoirs can even take place simultaneously.
The telescopic unit according to the present invention provides that at least two intermediate reservoirs, one for the high pressure and one for the low pressure, which are operatively connected to the hydraulic system (an SVE, for example), are hydraulically connected to the telescopic unit. The number of intermediate reservoirs should, however, not be limited thereto.
The supply of hydraulic energy to the hydraulic system is ensured by the intermediate reservoirs. In this case, the intermediate reservoirs can be configured as bladder reservoirs or piston reservoirs or spring reservoirs. The reservoirs for the high pressure and for the low pressure to be differentiated therefrom can be directly connected to the telescopic hydraulic cylinder via check valves.
In yet another embodiment of the telescopic unit according to the present invention the first intermediate reservoir for the high pressure is automatically filled, or energized via the hydraulic medium, that is, loaded with hydraulic energy, when the hydraulic pressure in the bottom chamber of the telescopic hydraulic cylinder is higher than the pressure in the first intermediate reservoir as such. This can, for example, be the case when telescoping out, with a static load, or when the telescopic hydraulic cylinder is extended up to the stop in the bolted and secured state.
In another advantageous embodiment of the telescopic unit according to the present invention, the hydraulic medium is automatically unloaded from the second intermediate reservoir as soon as the pressure of the hydraulic medium in the telescopic hydraulic cylinder is lower than the pressure of the hydraulic medium in the second intermediate reservoir. This can, for example, be the case when the valve on the bottom side of the telescopic hydraulic cylinder is opened (i.e. the friction will then be higher than the static load), or the telescopic hydraulic cylinder is retracted up to the stop in the bolted and secured state.
In order to ensure the functionality of the hydraulic system—by way of example that of an SVE—the pressures in the intermediate reservoirs can be measured with pressure sensors and processed in a control unit.
In another embodiment of the telescopic unit according to the present invention, depending on the pressure data determined by the pressure sensors and sent to said telescopic unit, [the] control unit and/or the computer activates the telescopic unit in order to load the intermediate reservoirs with hydraulic energy or unload hydraulic energy from them by changing the operating status.
In this connection, it should also be possible that the control unit controls the hydraulic system via the pressure sensors in order to energize the hydraulic system as soon as the control unit in the first intermediate reservoir detects an amount of hydraulic energy which is insufficient to supply the hydraulic system. In this case, the pressure sensors are configured such that they can convert the pressure of the hydraulic medium into a proportional electric signal.
For a better understanding, an X-way Y-chamber circuit is defined in the following as:
X-way is the number of connections to the cylinder chambers of the telescopic hydraulic cylinder via the check valves.
Y-chamber is the number of internal cylinder chambers of the telescopic hydraulic cylinder, where single-chamber represents the bottom side or the rod side. Two-chamber represents the bottom side and the rod side. The normal cylinder connections for driving the cylinder are not counted in this connection.
In another advantageous embodiment of the telescopic unit according to the present invention, the hydraulic system is supplied with the hydraulic medium via the rod side of the telescopic hydraulic cylinder in a hydraulic two-way single-chamber circuit.
In another embodiment, the hydraulic system is supplied with the hydraulic medium via the bottom side by the piston rod of the telescopic hydraulic cylinder in a hydraulic two-way single-chamber circuit.
In a further especially advantageous embodiment of the telescopic unit according to the present invention, the hydraulic system is supplied with the hydraulic medium via the rod side of the telescopic hydraulic cylinder in a hydraulic two-way two-chamber circuit. The oil can also be supplied to the hydraulic system via the bottom side of the telescopic hydraulic cylinder with a hydraulic two-way two-chamber circuit.
Furthermore, in an advantageous embodiment, the hydraulic system is supplied with the hydraulic medium via the rod side or the bottom of the telescopic hydraulic cylinder with a four-way two-chamber circuit.
It is especially advantageous to process the pressure sensor signals detected by means of the pressure sensor in the computer or in the control unit as such, so as to use the determined values to adjust the electric valves (poppet valves), via which loading and unloading of the intermediate reservoirs can be regulated or controlled. Conventional check valves could be replaced thereby. In this way, not only the loading and unloading of the intermediate reservoirs can be controlled, but it is thus also possible to limit the maximum pressure in the intermediate reservoirs. Furthermore, a defined pressure difference (delta-P) can be maintained while loading the intermediate reservoirs. In this way, the output capacity can be defined for the hydraulic system, and no further potential pressure adjustment will be necessary. Instead of the electric valves, hydraulically controlled valves can also be used in another embodiment.
In another especially advantageous embodiment of the telescopic unit according to the present invention, the hydraulic system is supplied with oil via the bottom side and the piston rod side of the telescopic hydraulic cylinder in a hydraulic three-way two-chamber circuit, the hydraulic system being connected to the cylinder tube of the telescopic hydraulic cylinder, and the returning oil being routed only into the bottom side.
According to a further especially advantageous embodiment of the telescopic unit according to the present invention, the oil for the hydraulic system is supplied via the piston rod side and the bottom side of the telescopic hydraulic cylinder in a hydraulic three-way two-chamber circuit, the hydraulic system being connected to the cylinder tube of the telescopic hydraulic cylinder, and the pressure oil being extracted only from the bottom side. It is also possible to extract the pressure oil from the piston rod side.
It is also advantageous if the oil for the hydraulic system is supplied via the piston rod side and the bottom side of the telescopic hydraulic cylinder in a hydraulic three-way two-chamber circuit, the hydraulic system being connected to the piston rod of the telescopic hydraulic cylinder, and the returning oil being routed only into the bottom side. The returning oil could also be routed only into the piston rod side.
The oil supply for the hydraulic system is also possible via the bottom side and the piston rod side of the telescopic hydraulic cylinder in a hydraulic three-way two-chamber circuit, where the hydraulic system is connected to the cylinder tube of the telescopic hydraulic cylinder, and where the returning oil can only be routed into the rod side.
Furthermore, the oil for the hydraulic system can be supplied via the piston rod side and bottom side of the telescopic hydraulic cylinder in a hydraulic three-way two-chamber circuit, where the hydraulic system is connected to the piston rod of the telescopic hydraulic cylinder, and where the returning oil can only be extracted from the rod side.
The invention will hereinafter be explained in more detail by means of exemplary embodiments with reference to the attached drawings. The figures show:
As shown in
The hydraulic system 18 is configured as an SVE in this embodiment. In other embodiments, the hydraulic system 18 can, for example, be designed for mounting or removing working equipment. The bolting and unbolting of working equipment, for example equipment for rotating, closing or opening appliances, such as, for example, grabs, grips, loading troughs and lifting platforms, is conceivable. For this purpose, a hydraulic medium is energized with hydraulic energy and routed to the hydraulic system 18.
The hydraulic system 18 is, as shown in
In the following, the path of the hydraulic medium in the feed line 21 downstream of the check valve 23 in the direction of the hydraulic system 18 will first be described. The check valve 23 prevents the hydraulic medium from accidentally flowing from the feed line 21 back to the bottom side 15 of the telescopic hydraulic cylinder 11. A bypass 25 is allocated to the feed line 21, which is connected to a first intermediate reservoir 26. In this embodiment, the intermediate reservoir 26 is configured as a bladder reservoir.
The changing operating statuses generate pressure differences in the telescopic hydraulic cylinder 11 and consequently also in the feed line 21. These pressure differences occur, for example, when driving loads or when driving against bolt holes or end stops, or the like. Even with unchanged load, different hydraulic pressures are generated in the telescopic hydraulic cylinder 11 owing to the different bottom to ring area ratios. These pressure differences represent an energy potential which can be used for additional work. The higher pressures in the hydraulic fluid are now routed via the bypass 25 into the intermediate reservoir 26 and stored for the time being.
The feed line 21 is connected to a control unit 27. The control unit 27 is in turn connected to the hydraulic system 18 via the feed line 21a. The control unit 27 detects and regulates the required hydraulic energy and makes it available from the intermediate reservoir 26 to the hydraulic system 18 if necessary.
Once the task has been accomplished, the “expanded” hydraulic medium is now routed out of the hydraulic system 18 into a return line 22a. The backflow of the hydraulic medium is regulated by the control unit 27 connected to the return line 22a. The expanded hydraulic medium is routed into a second intermediate reservoir 28 containing a hydraulic medium having a lower pressure compared to the first intermediate reservoir 26 via a bypass 26 and temporarily stored. The control unit 27 prevents the hydraulic medium from flowing back through the control unit 27 and on into the hydraulic system 18. The check valve 24 is connected to the feed line 19, from where the hydraulic medium is pushed back into the cylinder chamber 12 as the occasion arises.
The hydraulic system 18, the control unit 27, as well as the intermediate reservoirs 26, 28 along with the return lines 19, 21, 21a and 22, 22a and the check valves 23 and 24 are configured as movable together with the telescopic hydraulic cylinder 11. The hydraulic system 18 can, in this case, be mounted in a floating manner.
The hydraulic medium is stored in a storage tank 29, from where it is made available to the telescopic hydraulic cylinder 11 by means of a hydraulic pump 30 via adjustment and control means 31.
In another embodiment, which is not shown, the check valves 23, 24 and 37, 38 are replaced by electric poppet valves. These electric poppet valves are then also controlled by an electric control unit, taking into account the signals of the pressure sensor 42, 42a.
In this connection, the expanded hydraulic medium is routed from the intermediate reservoir 28 via the bypass 25a through the valve 24 into the bottom side 15 of the telescopic hydraulic cylinder 11 via the return line 32.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102012021544.4 | Oct 2012 | DE | national |
