EP0749935A1 - Method for controlling a telescopic multi-stage boom as well as the control system for carrying out the method - Google Patents

Abstract

The cylinder (6.1) of the first piston-cylinder unit (4.1) is linked to the fixed jib section on the piston connecting rod side. It is connected with a run-in conduit and on the piston side, as with all following cylinders (6.2-6.5), is connected via a run-out conduit with a pressure source. Between adjacent piston-cylinder units a valve is arranged in the piston-side conduits. The valve is formed as a separate component and on reaching the run-out end position of a piston-cylinder unit blocks the cylinder in question on the piston side and connects the pressure source via the run-out conduit with the following inwardly moved piston-cylinder unit (4.2-4.6) on the piston side.

Description

The invention relates to a method for controlling the telescopic extensions of a multiple telescopic boom of a crane or the like, in particular a loading crane, between the adjacent extensions of which a hydraulic piston-cylinder unit is arranged, the cylinders of which are connected to the preceding and the following The piston-cylinder unit is connected on the piston rod side in each case via a line and the cylinder on the piston side is to be connected via a line to a pressure source, the cylinder of the first piston-cylinder unit articulated on the fixed boom section for extending from its retracted state on the piston side a predetermined working pressure generated by a pressure source is applied, and each subsequent piston-cylinder unit is only subjected to the working pressure in its retracted state when the preceding piston-cylinder unit is extended.

The invention further relates to a control device for performing the aforementioned method for the telescopic extensions of a multiple telescopic boom for a crane or The like., In particular for a loading crane, between the adjacent extensions of which a hydraulic piston-cylinder unit is arranged, the cylinder of which is connected to the preceding and the following piston-cylinder unit on the piston rod side via a line, the cylinder of the the fixed boom section articulated first piston-cylinder unit on the piston rod side is connected to an inlet line and on the piston side as well as all subsequent cylinders is to be connected to a pressure source via an outlet line, and in each case one valve in the piston-side lines between adjacent piston-cylinder units is arranged, by means of which the respective subsequent piston-cylinder unit on the piston side is blocked relative to the previous piston-cylinder unit until the previous piston-cylinder unit is extended.

With multiple telescopic booms of cranes or the like. a hydraulic piston-cylinder unit is arranged between two adjacent telescopic extensions in order to extend one extension from its position retracted into the previous extension or to retract it from a position extended from the previous extension. The first and the largest cross-section of the extension which is adjacent to the relevant boom arm of the crane in the extended state is likewise connected to the boom arm via a piston-cylinder unit.

In more recent developments, a sequential control system can be used to ensure that when the extension is extended, the first extension (which is the largest in cross-section) extends, then the second extension etc., and finally the last (the smallest in cross-section), and that when retracting the Order is reversed.

From WO 93/08116 such a mechanical path sequence control for the telescopic extensions of a multiple telescopic boom of a loading crane is known, in which at the closed end of the hydraulic cylinder for the subsequent extension in the piston-like connecting line to the previous extension or its piston-cylinder - A shut-off valve is flanged onto the unit. This shut-off valve integrated in the hydraulic cylinder is closed in the retracted state of the following extension and is opened by a stop arranged on the previous extension when it has reached its extended end position. If an extension line leading from the pressure oil source to the first piston-cylinder unit is pressurized to extend the telescopic boom, only the first piston-cylinder unit extends with the first extension connected to it until it reaches its extended end position and thereby opens the flanged shut-off valve to the next piston-cylinder unit by means of a stop, so that now the second piston-cylinder unit is also pressurized on the piston side and can extend. This path-dependent sequence control is continued in the same manner in the further extensions or piston-cylinder units.

To retract the extensions, a non-return valve is connected to the bottom of each hydraulic cylinder, which is connected in parallel to the respective shut-off valves and is closed when extending. If an inlet line connecting the piston-cylinder units on the piston rod side is pressurized to retract, the pressure oil can initially only flow out of the last piston-cylinder unit, namely after opening a check valve in one of the last piston-cylinder units Tank leading, additionally provided return line. As a result, the last (outermost) extension is always retracted first. If this has reached its retracted end position, one opens on the piston of the last one (outermost) piston-cylinder unit provided the check valve, bridges the shut-off valve of the last piston-cylinder unit and thus causes hydraulic fluid to flow out of the piston-side cylinder space of the piston-cylinder unit following inwards, etc. until all piston Cylinder units and thus all extensions are retracted one after the other from the outside in.

A major disadvantage of this path sequence control is that the arrangement of the valves and stops is essentially fixed locally, which can not only lead to constructive difficulties, but also considerably limits their flexibility for different applications. A further disadvantage is that the valves are cylinder-bound, i.e. the cylinder and the piston form functional components of the valves and vice versa, since this is complex in terms of production technology and also expensive. Apart from that, the construction effort is great because, in addition to the hydraulics required to extend the extensions, a separate valve connected to the hydraulic cylinder and a return line leading to the last cylinder are required to retract the extensions.

The present invention has for its object to provide a generic method for controlling a multiple telescopic boom and a generic control device for performing the method, in which the extension of the extensions is as simple as possible in terms of circuitry, compact and with relatively little structural effort. As part of a subordinate task, both the extension and the retraction of the extensions are to be controlled essentially with the same hydraulic parts, so that no additional hydraulic parts are required to control the retraction.

In terms of the method, this object is achieved according to the invention in that the cylinder of a piston-cylinder unit is blocked on the piston side when the piston rod in question is extended; and that at the same time the pressure source is connected to a subsequent piston-cylinder unit, while the object with regard to the control device is achieved according to the invention in that the valve is designed as a separate component and, when the extended end position of a piston-cylinder unit is reached, the relevant one The cylinder locks on the piston side and connects the pressure source to a downstream, retracted piston-cylinder unit via the extension line.

As will be explained in more detail below, only the first cylinder is pressurized on the piston side in the sequence control according to the invention when the exit line is pressurized. After the piston-cylinder unit has reached its end-of-travel position, the cylinder in question is shut off by the valve provided between adjacent piston-cylinder units and designed as a separate component, the valve simultaneously directing the subsequent piston-cylinder unit, d. H. without interposing the previous piston-cylinder unit, connects to the pressure source, so that the cylinder is pressurized on the piston side, etc. A great advantage is that for the extension of a piston-cylinder unit, the subsequent locking of its cylinder and the To connect the pressure source to the subsequent piston-cylinder unit, only one valve is required, the position of which in relation to the piston-cylinder unit in question is also not mandatory for circuitry reasons.

Another advantage is that the valves can also be used to control the retraction of the extensions by the valve locking the cylinder of each inward following The piston-cylinder unit in its extended state cancels or unlocks when the piston rod of the piston-cylinder unit preceding to the outside has left its extended end position; and by the valve simultaneously connecting the relevant cylinder to the inward line.

With the sequence control according to the invention, it is consequently possible to achieve the considerable economic and manufacturing advantage of being able to work with identically designed, standardized valves and piston-cylinder units without additional hydraulic components being required for the retraction or without any additional structural outlay being required.

The valve is preferably a 3/2-way valve, the position of which in relation to the piston-cylinder unit can be freely selected within a certain range, so that the already structurally relatively complicated accommodation of the extensions and piston-cylinder units in the boom arm of a crane is not made more difficult by the control.

Further preferred embodiments of the present invention are described in the subclaims.

Fig. 1

eine schematisierte Seitenansicht eines Mehrfach-Teleskopauslegers mit sechs Ausschüben und den diesen zugeordneten Kolben-Zylinder-Einheiten;

Fig. 2

ein Schaltschema einer ersten Ausführungsform einer erfindungsgemäßen Steuereinrichtung;

Fig. 3

eine andere Darstellung des Schaltschemas gemäß Fig. 2;

Fig. 4

ein Schaltschema einer Variante einer erfindungsgemäßen Steuereinrichtung; und

Fig. 5

eine andere Darstellung des Schaltschemas gemäß Fig. 4.

The invention is explained in more detail below using exemplary embodiments with reference to a drawing. It shows:

Fig. 1

a schematic side view of a multiple telescopic boom with six extensions and the associated piston-cylinder units;

Fig. 2

a circuit diagram of a first embodiment of a control device according to the invention;

Fig. 3

another representation of the circuit diagram of FIG. 2;

Fig. 4

a circuit diagram of a variant of a control device according to the invention; and

Fig. 5

another representation of the circuit diagram according to FIG. 4.

Fig. 1 shows a schematic side view of a whole with 1 designated multiple telescopic boom with six extensions 2.1 to 2.6 in the fully extended state. In the fully retracted state, the last (outermost) extension 2.6 has moved into the previous extension 2.5, this into the previous extension 2.4 u.s.f. and the first extension 2.1 in the hollow boom section 3 of an articulated arm or the like, which is therefore stationary with respect to the direction of extension or retraction.

A piston-cylinder unit 4 is assigned to each extension 2. The piston-cylinder unit 4.1 assigned to the first extension 2.1 is articulated with its piston rod 5.1 on the boom section 3 and is fixed with its cylinder 6.1 via a flange 7.1 to the outer end of the extension 2.1. Of the piston-cylinder unit 4.2 assigned to the extension 2.2, only the piston rod 5.2 can be seen in FIG. 1, since its cylinder 6.2 lies behind the cylinder 6.1, the cylinder 6.2 on the flange 7.1 and the outer end of the piston rod 5.2 on an outer end of the extension 2.2 attached flange 7.2 is attached.

The cylinder 6.3 of the piston-cylinder unit 4.3, also fastened to the flange 7.2, for the next extension 2.3 is located behind the piston rod 5.2. Its piston rod 5.3 is attached to a flange attached to the outer end of the extension 2.3 7.3, to which in turn the cylinder 6.4 of the piston-cylinder unit 4.4 for the next extension 2.4 is also fastened, the piston rod 5.4 of which is articulated on a flange 7.4 fastened at the end of the next extension 2.4, and so on the piston-cylinder units 4 to be able to arrange and accommodate them in a suitable manner, since a piston-cylinder unit 4 must be arranged between adjacent extensions 2, and the piston-cylinder units 4 not only in the The extended position shown must be arranged in a suitable manner, but also in the retracted position retracted into the boom section 3, in which the flanges 7.1-7.6 are directly adjacent to one another.

As has already been explained above, the telescopic boom 1 should be controlled so that when entering from the position shown in FIG. 1, the last, outermost extension 2.6 first moves into the inward extension 2.5, then the one (containing extension 2.6) ) Extension 2.5 in the interior extension 2.4 and so on.

In addition, the control should ensure that when extending, only the first extension 2.1 extends from the boom section 3, then only the second extension 2.2 from the extension 2.1 and the like.

Fig. 2 shows a circuit diagram for a control device which ensures a corresponding sequence control for both extending and retracting, with an intermediate state is shown in Fig. 2, in which the three piston-cylinder units 4.1-4.3 are already extended and have reached their extended end position while the subsequent piston-cylinder units 4.4-4.6 (and thus their extensions 2.4-2.6) are still retracted.

It can be seen from FIG. 2 that the cylinders 6 of the piston-cylinder units are to be connected to a pressure source 10 on the piston side via an extension line 9 provided with a load-holding valve 8, 3/3 between adjacent piston-cylinder units 4 / 2-way valves 11.1-11.5 are switched. The 3/2-way valves 11 divide the extension line 9 into sections, namely into the extension line 9.1 before the 3/2-way valve 11.1, the extension line 9.2 between the 3/2-way valves 11.1 and 11.2, and the extension line 9.3 between the third / 2-way valves 11.2 and 11.3 etc. and finally the exit line 9.6 behind the 3/2-way valve 11.5. Already at this point, reference is made to the fact that the 3/2-way valves 11 are each assigned a preload valve 12 connected in parallel, which u. a. serves as a backup.

If the telescopic boom 1 is initially in a fully retracted state and the extension line 9.1 is pressurized, the 3/2-way valve 11.1, like all subsequent 3/2-way valves 11.2-11.5, is in its basic position and thereby connects the Extension line 9.1 on the piston side with the cylinder 6.1 of the relevant piston-cylinder unit 4.1. The connection of the 3/2-way valves to the following exit line 9.2 or 9.3 etc. is blocked in the basic position of the 3/2-way valves 11. As a result, only the cylinder 6.1 of the first piston-cylinder unit 4.1 is pressurized on the piston side, so that the cylinder 6.1 moves out of its (not shown) retracted position with the extension 2.1 and moves relative to its piston rod 5.1.

The 3/2-way valve 11.1 remains in its basic position until the piston-cylinder unit 4.1 has not yet reached its extended end position. If this is the case, the 3/2-way valve 11.1 is automatically switched to a second position, thereby simultaneously connecting to the relevant one Cylinder 6.1 is locked and the extension line 9.1 is connected to the extension line 9.2. The 3/2-way valve 11.2 is in its basic position, since the piston-cylinder unit 4.2 in question is still in its retracted state, so that the pressure generated by the pressure source 10 on the piston 6.2 is now directly in the cylinder 6.2 via the extension lines 9.1 and 9.2 and the 3/2-way valve 11.2 can set. Here, too, the connection of the 3/2-way valve 11.2 to the subsequent exit line 9.3 is initially blocked.

The sequence described is particularly clear in FIG. 2 using the example of the piston-cylinder units 4.3 and 4.4, since the piston-cylinder unit 4.3 is already fully extended and the piston-cylinder unit 4.4 is still fully retracted. While the 3/2-way valve 11.3 is already switched and thus blocks the connection to the cylinder 6.3 and connects the extension line 9.3 with the extension line 9.4, the 3/2-way valve 11.4 is still in its basic position and connects the extension line 9.4 on the piston side to the Piston-cylinder unit 4.4, so that its cylinder 6.4 is essentially neglected with the pressure generated by the pressure wave 10 and neglects the pressure losses and extends with the extension 2.4. When the piston-cylinder unit 4.4 reaches its extension end position, the 3/2-way valve 11.4 is also switched, whereby the connection to the cylinder 6.4 is blocked and the extension line 9.4 is connected to the extension line 9.5. Through the successive locking of the cylinders 6 from the piston-cylinder units 4 in their extended end position and the simultaneous forwarding of the pressure generated by the pressure source 10 to the subsequent extension line 9, any number of piston-cylinder units 4 or Activate push-out 2 in a simple way.

The activation means 13 are provided in the circuit diagram according to FIG. 2 as mechanical means, whereby they also e.g. can be electrical or hydraulic.

In order to cause the extensions to retract in the reverse order in the sequence control according to FIG. 2, the inlet line 15.1 is pressurized by the pressure source 10 via the load-holding valve 8, the piston-cylinder units 4 on the piston rod side in each case via an inlet line section 15.2 or 15.3 etc. are connected to the subsequent piston-cylinder unit 4. Unlike when extending or in the extension line, the pressure is applied to all piston-cylinder units 4.1-4.6 or to their piston ring surfaces 14.1-14.6 at the same time. Since in the first five piston-cylinder units 4.1-4.5 the respective assigned 3/2-way valve 11.1-11.5 is switched when extending after reaching the extended end position so that its cylinder 6.1-6.5 is blocked on the piston side around the extension line 9 to be connected directly to the subsequent one, the only non-locked piston-cylinder unit 4.6 is first retracted due to the pressure on the piston rod side, the nonreturn valve 16, which is connected in parallel with the preload valve 12.6, opening.

After the last (outermost) piston-cylinder unit 4.6 has been retracted, a pressure increase occurs on the piston side in the cylinder 6.5 of the piston-cylinder unit 4.5 following inwards due to the pressurization on the piston rod side, which initially affects the 3 / 2- Directional valve 11.5 assigned preload valve 12.5 opens and oil can flow out of the cylinder 6.5 on the piston side via line 9.5. After the switching path of the 3/2-way valve 11.5 has been bridged, it is switched back to its basic position or released again, so that the piston-side blocking of the cylinder 6.5 is released. This process continues continue the inward following 3/2-way valves 11 and piston-cylinder units 4 in the same way until the first 3/2-way valve 11.1 is released and thus the first piston-cylinder unit 11.1 is retracted, so that the retraction basically - but in reverse order - how to extend.

The latter is again particularly clear in FIG. 2 on the basis of the piston-cylinder units 4.4 and 4.3. If it is assumed that the piston-cylinder unit 4.4 has just been retracted and the 3/2-way valve 11.4 in question is accordingly switched back to its basic position by the release means 13, it is due to the piston-cylinder unit 4.3 which follows inwards the pressure on, so that the preload valve 12.4 opens due to the pressure increase on the piston side and after the start of the retracting movement of the piston rod 5.3 the 3/2-way valve 11.3 is switched back and the oil in the cylinder 6.3 can flow back on the piston side via line 9.3.

As indicated in Fig. 2 with a dash-dotted line, the 3/2-way valves 11 with their bias valves 12 form a switching unit, by means of which both the extension and the retraction are controlled. In addition, the switching units are not structurally coupled to the piston-cylinder units 4, so that their position is not mandatory and there is constructive freedom in the arrangement or accommodation of the extensions 2 and piston-cylinder units 4.

FIG. 3 shows the switching arrangement according to FIG. 2 with simultaneous assignment to the representation according to FIG. 1 in a different representation for the purpose of further clarification, but all piston-cylinder units being fully extended in accordance with FIG. 1.

In a variant of a sequence control according to the invention according to FIG. 4, the extension arrangement of the individual piston-cylinder units 4 corresponds to that according to FIG. 2. 4 is completely identical in terms of circuitry to the circuit diagram according to FIG. 2 and differs therefrom only in the type of hydraulic supply for the extension. 2, the extension lines 9.n each run outside the cylinders 6 and are generally formed by hose lines, the oil supply according to FIG. 4 takes place via a fixed piping, which extends through the individual piston-cylinder units 4, such as 4 can be clearly seen from the course of the exit line sections 9.n. The fixed piping in the cylinders 6 consists of two tubes that can be pushed into each other and have no connection to the cylinder chamber. The fixed piping has the advantage that the outer hose lines which are to be installed and guided with considerable effort are dispensed with and the operation of the control device is further simplified.

The circuit diagram according to FIG. 4 is also shown in a different way in FIG. 5 for the purpose of illustration, all piston-cylinder units in FIG. 5 being fully extended in accordance with FIGS. 1 and 3.

It should be added that both the 2/3 directional control valves 11 and the preload valves 12 are each assigned a check valve 16 connected in parallel.

Reference list

1

Multiple telescopic boom

2nd

Extension

3rd

Boom section

4th

Piston-cylinder unit

5

Piston rod

6

cylinder

7

flange

8th

Load holding valve

9

Exit line

10th

Pressure source

11

3/2-way valve

12th

Preload valve

13

Activation means

14

Piston ring surface

15

Entry line

16

check valve

Claims (14)

Method for controlling the telescopic extensions (2) of a multiple telescopic boom (1) of a crane or the like, in particular a loading crane, between the adjacent extensions (2) of which a hydraulic piston-cylinder unit (4) is arranged, whose cylinder (6) is connected to the preceding and the following piston-cylinder unit (4) on the piston rod side via a line (15), and whose cylinder (6) on the piston side via a line (9) to a pressure source (10) connect, the cylinder (6) of the first piston-cylinder unit (4.1) articulated on the fixed boom section (3) being acted upon by a predetermined working pressure generated by a pressure source (10) on the piston side in order to move out of its retracted state, and each subsequent piston-cylinder unit (4.2-4.6) is only subjected to the working pressure in its retracted state when the previous piston-cylinder unit (4.1-4.5) is off driven, characterized in that the cylinder (6) of a piston-cylinder unit (4) is blocked on the piston side when the relevant piston rod (5) is extended; and that at the same time the pressure source (10) is connected on the piston side to a subsequent piston-cylinder unit (4). A method according to claim 1, characterized in that the piston-cylinder units (4) are connected to the pressure source to extend one after the other directly or without interposing a preceding piston-cylinder unit (4). A method according to claim 1 or 2, characterized in that the last piston-cylinder unit (4.6) for extending on the piston side is acted upon directly by the predetermined working pressure generated by the pressure source (10), and in that the preceding piston-cylinder units ( 4.1-4.5) are blocked on the piston side. Method according to one or more of the preceding claims, characterized in that the cylinders (6) of the piston-cylinder units (4) in their extended state are acted upon by the predetermined working pressure generated by the pressure source (10) on the piston rod side; and that the piston rod (5.6) of the last piston-cylinder unit (4.6), which is not locked on the cylinder (6.6), is retracted first. Method according to claim 4, characterized in that the blocking of the cylinder (6.5, 6.4, ...) of each piston-cylinder unit (4.5, 4.4, ...) following inwards is released in its extended state when the piston rod (5.6 or 5.5, 5.4 ...) of the piston-cylinder unit (4.6 or 4.5, 4.4 ...) preceding to the outside has left its extended end position; and that at the same time the cylinder in question (6.5, 6.4, ..) for retracting with the one following inwards Line (9.5, 9.4 ...) is connected. Control device for the telescopic extensions (2) of a multiple telescopic boom (1) for a crane or the like, in particular a loading crane, between the adjacent extensions (2) of which a hydraulic piston-cylinder unit (4) is arranged, whose cylinder (6) is connected to the preceding and the following piston-cylinder unit (4) on the piston rod side via a line (15), the cylinder (6.1) of the first piston-cylinder articulated on the fixed boom section (3) The unit (4.1) is connected on the piston rod side to an intake line (15) and on the piston side as well as all subsequent cylinders (6.2-6.5) is to be connected to a pressure source (10) via an extension line (9), and in the piston side lines (9. n) a valve (11) is arranged between adjacent piston-cylinder units (4), by means of which the subsequent piston-cylinder unit (4.2-4.5) on the piston side compared to the previous one going piston-cylinder unit (4.1-4.5) is blocked until the previous piston-cylinder unit (4.1-4.5) is extended to carry out the method according to one or more of the preceding claims, characterized in that the valve ( 11) is designed as a separate component and blocks the relevant cylinder (6) on the piston side when the end position of a piston-cylinder unit (4) is reached and the pressure source (10) via the extension line (9) with a subsequent, retracted piston Connects cylinder unit (4.2-4.6) on the piston side. Control device according to claim 6, characterized in that the valve (11) keeps the connection to a subsequent piston-cylinder unit (4.2-4.6) blocked until the piston-cylinder unit (4) has reached its extended end position. Control device according to claim 6 or 7, characterized in that the valve (11) releases the blocking of the cylinder (6.5-6.1) of each piston-cylinder unit (4.5-4.1) following inwards in its extended state when the piston rod (5.6 -5.2) the piston-cylinder unit (4.6-4.2) preceding to the outside has left its extended end position; and that the valve (11) at the same time connects the relevant cylinder (6.5-6.1) for retraction with the inward line (9.5-9.1). Control device according to one or more of claims 6 to 8, characterized in that the valve (11) and a biasing valve (12) connected in parallel form a switching unit which is designed such that the biasing valve (12) is effective when a Cylinder (6) is blocked on the piston side by the valve (11) and vice versa. Control device according to one or more of claims 6 to 9, characterized in that the valve (11) is assigned an activation means (13), by means of which the piston-cylinder unit (4) is reached when the extended or retracted position is reached Lock or unlock the relevant cylinder (6). Control device according to claim 10, characterized in that the activation means (13) can be actuated electrically or hydraulically. Control device according to one or more of claims 6 to 11, characterized in that the valve (11) in a first (basic) position connects the pressure source (10) to the cylinder (6) of the relevant piston-cylinder unit (4) and after switching to a second position, the pressure source (10) connects to the cylinder (6) of a subsequent, retracted piston-cylinder unit (4). Control device according to one or more of claims 6 to 12, characterized in that the valve (11) is a 3/2-way valve. Control device according to one or more of claims 6 to 13, characterized in that the extension lines (9) run in the longitudinal direction through the respective cylinder (6) and are designed as tubes which can be pushed into one another.

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