EP0038954B1 - Self-propelled concrete pump - Google Patents

Abstract

A vehicular concrete pump assembly having a semitrailer and a truck tractor interconnected therewith with a mechanism being provided on the semitrailer for elevating the truck tractor and supporting it in the raised position while the semitrailer is braced on the ground by extendable support legs to enable the raised truck trailer to operate as ballast to stabilize the semitrailer against the weight of an articulated concrete distribution pole having a concrete line through which concrete is distributed by a pump on the semitrailer.

Description

The invention relates to a self-propelled concrete pump of the type specified in the preamble of claim 1.

Concrete pumps of this type convey the concrete delivered by transport mixers to construction sites via a placing boom into a formwork. The concrete pumps are usually mounted on 2-, 3- and 4-axle truck chassis with a continuous, rigid frame. For very heavy vehicles with a total weight of more than 24 t, multi-axle heavy chassis with excessive axle loads are necessary, as is the case with mobile cranes. They are only allowed to drive on public roads with a special permit and cannot use many lighter routes and bridges.

Furthermore, it is known in a self-propelled concrete pump of the type specified in the preamble of claim 1 to use the semitrailer of a semitrailer as a chassis for the concrete pump and the placing boom (DE-A-2 737 884). In the working position, in which the placing boom is actuated and concrete is being conveyed, the semitrailer is unhitched. In order to ensure the necessary stability, the semitrailer must therefore be provided with the appropriate ballast, which is formed there by a heavy ramp for a truck mixer, which is arranged at the front in the direction of travel and in front of the concrete hopper. Accordingly, the rotating tower of the placing boom is arranged at the rear end of the semitrailer.

The larger the placing boom, the closer you get to the permissible weight limit for semi-trailers, which is currently 38t t total weight in the Federal Republic of Germany, for example. Taking this weight limit into account, in the known semitrailer concrete pump with ballasted or correspondingly heavy semitrailer, the placing boom can only have a length of up to approximately 32 m. In addition, it is disadvantageous that this heavy ballast has to be transported in a cost-increasing manner.

The invention has for its object to improve the known self-propelled concrete pump of the type specified in the preamble of the claim that with a relatively light design of the semitrailer without sacrificing stability, a considerable increase in the range of the placing boom is achieved without a prescribed weight limit of entire tractor-trailer is exceeded.

To achieve this object, the combination of features specified in claim 1 is proposed according to the invention. Further advantageous refinements and developments of the invention emerge from the subclaims.

With the arrangements according to the invention it is achieved that the tractor unit with its weight of approx. 7 to 9 t can be used as ballast for stabilizing the placing boom.

Before the tractor unit is lifted according to the invention, the support legs provided on the semitrailer are pivoted laterally outward into their prescribed position and supported on the ground by means of a telescopic device while lifting the semitrailer. The front support legs pointing forward by about 45 ° to the vehicle axle expediently extend in front of the front axle of the tractor unit. Because of the large reach of the support legs to the front, the semitrailer, which is about 0.5 to 1 m longer than a vehicle with a rigid chassis, does not suffer any loss of useful range. This is due to the fact that the front axle is not used as the foremost safety edge, as is the case with mobile cranes, but rather the connecting line running in front of the front axle approximately in the area of the bumper of the tractor unit between the floor support points of the front support legs. The same also applies to a vehicle with a fixed common frame between the concrete pump and motor drive, provided that corresponding swing-out support legs are provided. However, the semitrailer has the advantage that it is not limited to a total weight of 22 to 24 tonnes, like a fixed vehicle, in order to be able to drive on public roads without restrictions, but up to 38 tonnes total weight with a 5-axle design and up to 32 tonnes total weight with 4-axle design.

An additional weight of 8 tonnes for the tractor unit, with a support width of 8 m, allows an increase in the load moment of the placing boom by 30 to 40 mt and thus a corresponding increase in its length. The use of a semitrailer with a three-axle tractor unit and a two-axle semitrailer with a total weight of 38 t enables the construction of a placing boom with a reach height of up to 44 m and a horizontal outreach of approx. 40 m with a support width of approx. 8 m. In the case of a fixed, non-kinking vehicle, a 5-axle special chassis would be required, which may only drive on public roads with large travel restrictions and special permits. This restriction is particularly unsustainable for service companies that have to drive many different types of work every day because of the high investment and transport costs. It is eliminated by the construction according to the invention.

The most common three-axle Fa'.t test so far with non-kinking chassis, the maximum permissible total weight for a driving area without restriction in the Federal Republic of Germany z. Is currently 24 t, can be equipped with placing booms with a reach height of up to 32 m. In comparison, the reach height of the placing boom can be increased by 12 m to 44 m with a semitrailer tractor with the features according to the invention and a permissible total weight of 38 t.

From DE-C-1 026499 and 1 091 304 it is known per se in a rotating crane with semi-trailer to raise the semi-trailer in the working position of the rotating crane and in the raised position as a ballast weight to stabilize the semi-trailer supported on the ground with support legs use. However, the tractor and its lifting and holding means are not arranged there on the fixed part of the semitrailer, but on a boom of the pivotable upper part of the slewing crane. The semitrailer also swings around the crane axis, which is opposite the fifth wheel, and thus serves as a swiveling ballast. For a swiveling ballast, which is only lifted a few centimeters from the ground, there is neither enough space for slewing cranes nor for concrete pumps to move it over obstacles, vehicles, fences, barriers etc. on the ground. Swing away. That is why the slewing ballast for mobile cranes is usually only installed at a height of 2-3 m, i.e. at a height to which a semi-trailer cannot be lifted.

This problem was avoided in the subject of the application in that the lifting and securing means for the tractor unit were arranged on the fixed part of the semitrailer near the end containing the axis of rotation, so that the tractor unit does not have to be pivoted with the placing boom.

• Fig. 1 eine Seitenansicht einer Sattelzug-Betonpumpe im Zustand der Straßenfahrt mit eingeschwenkten Stützbeinen und zusammengeklapptem Verteilermast;
• Fig. 2 eine Draufsicht auf einen Ausschnitt der Sattelzug-Betonpumpe nach Fig. 1 mit ausgeschwenkten Stützbeinen;
• Fig. 3 einen vergrößerten Ausschnitt aus Fig. 1 mit einem bevorzugten Hubmechanismus und den Schaltorganen einer Sicherungseinrichtung;
• Fig. 4 eine Stirnseitenansicht des Hubmechanismus nach Fig. 3 mit einem Hydraulikzylinder;
• Fig. 5 eine Stirnseitenansicht des Hubmechanismus nach Fig. mit zwei Hydraulikzylindern;
• Fig. 6 und Fig. 7 zwei weitere Ausführungsbeispiele mit abgewandelten Hubmechanismen in einer ausschnittsweisen Seitenansicht.

In the drawing, some preferred embodiments of the semitrailer concrete pump according to the invention are shown in a schematic manner. It shows

• Figure 1 is a side view of a tractor-trailer concrete pump in the state of driving on the road with pivoted support legs and folded boom.
• FIG. 2 shows a plan view of a section of the tractor-trailer concrete pump according to FIG. 1 with the support legs pivoted out;
• 3 shows an enlarged detail from FIG. 1 with a preferred lifting mechanism and the switching elements of a safety device;
• FIG. 4 shows an end view of the lifting mechanism according to FIG. 3 with a hydraulic cylinder;
• 5 shows an end view of the lifting mechanism according to FIG. 2 with two hydraulic cylinders;
• FIGS. 6 and 7 show two further exemplary embodiments with modified lifting mechanisms in a partial side view.

The mobile concrete pump contains a semitrailer, on the semitrailer 10 of which a placing boom 13 is rotatable on a turret 11 about a vertical axis and can be unfolded by hydraulic means 12, the concrete line 14 of which can be loaded with the concrete to be conveyed via a charging container 15 and a pump unit 16 . A total of four support legs 17, 18 which can be swung out laterally and telescopically extended are provided on the semitrailer 10 (cf. FIG. 2). The tractor unit 20 is detachably connected to the kingpin 19 of the semitrailer 10 via a fifth wheel coupling 21 known per se. The bolt 22 ensures that both vertical and horizontal power transmission via the coupling is possible and that the tractor unit can still be pivoted about the vertical axis of the kingpin 19 relative to the satellite trailer 10. For safety reasons, the bolt 22 can be fixed on the fifth wheel coupling 21 by means of a suitable screw connection in such a way that it cannot be easily removed by the operating personnel. The pivot bearing 23 additionally provided on the fifth wheel coupling allows the tractor 20 to pitch about a horizontal transverse axis relative to the semitrailer 10.

At the front end of the semitrailer 10, lifting and holding means 29, which are also referred to below as the lifting mechanism, are arranged between the semitrailer and the tractor unit.

In the exemplary embodiments shown in FIGS. 1 to 5, the lifting mechanism 29 contains at least one lever 30 which is articulated on the turret 11 of the placing boom 13 or on the frame of the semitrailer 10. The lever 30 can be pivoted up and down with the aid of a hydraulic cylinder 31 about a horizontal axis running transverse to the direction of travel (FIG. 4). Instead of one, two hydraulic cylinders 31 can also be provided, the stroke of which can be coordinated with one another by means of a cross rod 33 (FIG. 5).

At the free end of the lever 30, two pull strands designed as link chains 34 are suspended, which have at their lower end an eyelet 37 which can be hung on a head bolt 36 which projects laterally beyond the chassis frame 35 of the tractor unit 20. The head bolts 36 are expediently arranged on a crossbar 38 fastened to the chassis frame 35, which has a further head bolt 39 in its central region located in the longitudinal center plane of the tractor unit. The link chains 34 serve as a pulling element, by means of which the tractor unit can be lifted off the ground when the lever 30 is pivoted up with the aid of the hydraulic cylinder 31.

In the exemplary embodiments according to FIGS. 6 and 7, the lifting mechanism 29 contains a hydraulic cylinder 31 ′ attached to the semitrailer 10 or to its structure, the piston rod 45 of which has an eye 47 or a hook at the free end, on which the traction element designed as a chain or rope 34 is attachable. Instead of one, two hydrocyclines can be used the 31 'can be used. In the case of the exemplary embodiment shown in FIG. 6, the slack pulling member 34 is guided over a deflection roller 46 located on the semitrailer.

In practical operation, after the semitrailer arrives at the construction site, the semitrailer 10 with its structure consisting of pump unit 16 and placing boom 13 is first raised by swiveling out and extending the support legs 17, 18, so that the rear wheels 40 are largely or completely lifted off the ground. At the same time, the double axle 41 of the tractor unit 20 is pulled up via the closed fifth wheel 21. The support legs 17, 18 are approximately in the position indicated in FIG. 2.

The lifting mechanism 29 is then actuated. Especially if the tractor unit 20 is not exactly aligned with the semitrailer 10 after arriving at the construction site, the link chains 34 are initially attached to the central headed bolts 39. When the hydraulic cylinder or cylinders 31 and 31 'are actuated, the front part of the tractor unit 20 is then raised slightly and, after the front wheels 42 has been lifted off, aligned in a position aligned with the semitrailer 10. After lowering the tractor again, the link chains 34 can then be hung on the laterally projecting head bolts 36. When the hydraulic cylinder 31 or 31 'is subsequently actuated, the tractor unit 20 is lifted off the ground with its front wheels 42 and then acts as a ballast weight for stabilizing the semitrailer when the distribution boom is extended when the rear wheels 41 also come free from the ground.

So that the tractor unit 20 does not execute any undesired vibrations when the heavy placing boom 13 is pivoted, it can be locked in the aligned position. This can be done with a wedge, not shown, which is known per se and which is inserted hydraulically into the insertion slot of the fifth wheel coupling 21. For this purpose, additional hydraulic cylinders, not shown in the drawing, can be attached between the semitrailer 10 and the chassis 35 of the tractor unit 20. Even with the aid of fixed tie rods, triangular links or the like (not shown in the drawing), instead of the link chains, the raised tractor unit can be fixed relative to the semitrailer.

To prevent inadvertent extension of the placing boom when the weight of the boom load is insufficient, a safety device is provided that blocks the pressure oil supply to the distributor boom hydraulics when the semitrailer is unsaddled and / or when the tractor unit is not lifted off the ground. For this purpose, two switching valves 44, 45 designed as an opener are arranged on the semitrailer, which are actuated in one case by the coupling plate of the fifth wheel coupling 21 and in the other case by the lever 30 in its upwardly pivoted end position (FIG. 3). Of course, the security device can also be implemented in other ways, such as. B. by a responsive to the load of the raised tractor unit, connected to the hydraulic cylinder 31 pressure switch valve.

The link chains 34 allow the tractor to be swiveled back into the original position, which has been developed relative to the semitrailer, after the work has been completed by briefly lowering the chains 34 at another point on the chassis frame 35 or the cross member 38 after a short lowering of the front part that the tractor can be swiveled towards the intended side when the trailer is raised again. The semitrailer can then move back in its original direction of travel and leave the construction site, especially in narrow construction sites.

To save a separate motor on the semitrailer, it is possible to use the vehicle motor of the tractor unit 20 to drive the pump unit 16. This can be done with the help of articulated hydraulic lines that can be laid between the tractor unit and the semitrailer. Another possibility is that in the working position with the tractor unit raised, a mechanical coupling between the tractor unit and the semitrailer trailer is engaged, which non-positively connects a hydraulic pump arranged on the semitrailer with the vehicle engine of the tractor unit via a cardan shaft. With regard to the required pumping power, however, this requires a powerful vehicle engine in the tractor unit. There is also the restriction that the semitrailer can no longer be connected to any tractor unit.

With the lifting mechanism described above, it is also possible in principle to lift another ballast weight in the unsaddled state instead of the tractor unit. This is of advantage, for example, if the tractor unit also has to be used or repaired in another way and downtimes of the concrete pump at the construction site are to be avoided.

Instead of a hydraulic cylinder 31 or 31 ', a cable winch, not shown in the drawing, can also be used as the lifting mechanism. If the cable winch is arranged in the rear region of the semitrailer 10 in the vicinity of the loading container 15, it can, if necessary, also be used as a towing winch for the vehicle.

In principle, an arrangement is also conceivable in which the semitrailer 10 and the tractor unit 20 are only connected to a taut traction member the, so that the lifting of the tractor can then take place without an additional lifting mechanism when extending the front support legs.

Claims (16)

1. A travelling concrete pump with a distributor mast (13), which can be unfolded by hydraulic means (12) and is arranged to rotate about a vertical pivot on a semi-trailer (10) associated with a tractor and supportable on the ground by extensible supporting legs (17. 18), and with a concrete-charging funnel (15) arranged on the semi-trailer and a tractor (20) connectible with the semi-trailer (10) by means of a coupling (21), characterized in that means (29) for raising the tractor (20) and for securing it in the raised position are arranged on the stationary part of the semi-trailer (10), the tractor (20), when in the raised position, forming a ballast weight for stabilizing the semi-trailer (10), supported on the ground by the supporting legs (17, 18), when the distributor mast (13) is extended, and in that the pivot (11) for the distributor mast (13) as well as the raising and securing means (29) are arranged in the zone of the coupling-side end, and the charging funnel (15) is arranged at that end of the semi-trailer (10) that is at the rear in the direction of travel.

2. A concrete pump according to Claim 1, characterized in that the raising and securing means (29) comprise at least one traction member (34), which can be secured, in the direction of travel, in front of the coupling (21) and between the semi-trailer (10) and at least one •ubjacent point (36, 39) on the tractor (20), and in that, when the coupling (21) is engaged and the supporting legs (17, 18) are extended, the tractor (20) can be completely lifted from the ground by its front and rear wheels (41,42).

3. A concrete pump according to Claim 1 or Claim 2, characterized in that the raising and securing means (29) comprise at least one lever (30) which can be connected to the trailer-side end of the traction member (34) and which is linked to the semi-trailer (10) or its mounting and can be swung, by at least one hvdraulic cylinder (31), about a horizontal axis extending transversely of the direction of travel.

4. A concrete pump according to Claim 1 or 2, characterized in that the lifting and securing means (29) comprise at least one hydraulic cylinder (31') which is linked to the semi-trailer (10) and by its associated piston-rod (45) directly engages the traction member (34).

5. A concrete pump according to Claim 4, characterized in that the traction member (34), of flexible design, is guided, round a roller (46) arranged on the semi-+railer (10), from a suspension point on the tractor (20) to the hydraulic cylinder (31 linked in the lower zone of the semi-trailer.

6. A concrete pump according to Claim 2, characterized in that the tractor (20), connected to the trailer (10) by way of the traction member (34), can be raised from the ground with the help of the extensible supporting legs (17) that are located at the front as seen in the direction of travel.

7. A concrete pump according to any one of Claims 2 to 6, characterized in that the traction member (34) consists of at least one strand preferably in the form of a chain.

8. A concrete pump according to any one of Claims 2 to 4 or Claim 6, characterized in that the traction member consists of at least one rigid tie-rod or a triangular guide.

9. A concrete pump according to any one of Claims 2 to 8, characterized in that there are provided, on the chassis (35) or a cross-member (38) of the tractor (20), two fixing points (36) for the traction member (34) consisting of two parts extending downwardly from these points which are of mirror-symmetrical arrangement with respect to the vertical longitudinal middle plane of the tractor.

10. A concrete pump according to Claim 9, characterized in that a further fixing point (39) for the traction member (34) and arranged approximately in the longitudinal middle plane is provided on the chassis (35) or on the cross-member (38).

11. A concrete pump according to any one of Claims 1 to 10, characterized by a safety device (44, 45) which cuts off the supply of pressurized oil to the distributor mast hydraulic system when the coupling (21) is disengaged and/or when the tractor (20) is not raised.

12. A concrete pump according to Claim 11, characterized in that the safety device comprises a safety switch which is preferably in the form of a pressure-witching valve which h triggered by the load lifted by the raising and fixing means (29).

13. A concrete pump according to Claim 11 or 12, characterized in that the safety device comprises a safety switch, preferably in the form of a hydraulic limit valve, which is in its non-blocking position when the raising and fixing means (29) are in the upper position and/or when the coupling (21) is engaged.

14. A concrete pump according to any one of Claims 1 to 13, characterized in that, when in the position in which it is raised from the ground, the tractor (20) can be straightened in the longitudinal direction of the semi-trailer (10) and can be secured to the semi-trailer (10) in the straightened position, preferably with the help of a blocking wedge introduced into the coupling (21).

15. A concrete pump according to any one of Claims 1 to 14, characterized in that there is arranged ci the semi-trailer (10) a hydraulic pump for driving the distributor mast and/or the concrete pump, which hydraulic pump can be connected to the vehicle motor of the tractor (20) when the latter is in the raised position.

16. A concrete pump according to any one of Claims 1 to 15, characterized in that the pivot (11) for the distributor mast (13) and the raising and fixing means (29) are arranged in the zone of the coupling-side end of the semi-trailer (10).

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