EP0513942B1 - Lifting device for a finisher - Google Patents

Description

The invention relates to a lifting device for a compaction screed with a rotating or about a vertical axis. pivotable operating station provided paver, the compaction screed is articulated at one end section of two parallel support arms each running on a longitudinal side of the paver in its longitudinal direction, each of which are articulated at their other end section on the frame of the paver, so that the support arms are lowered together from one Working position, in which the compaction screed lies on the paving material to be compacted, must be swung up into a raised transport position, with a piston-cylinder unit for each support arm arranged above the support arms, each at one end on the paver's frame and at the other end is articulated on the relevant support arm, the piston-cylinder units preferably being designed hydraulically and consequently in each case one end of a piston-cylinder unit of whose cylinder and the other end is formed by the free end of its piston rod, which in turn carries at its other end the piston which is displaceable in the cylinder when pressure medium is applied.

The support arms of road pavers, designed as swivel arms, are therefore connected to the frame of the road paver via piston-cylinder units in order to be able to lift the compaction screed from its lowered working position into a transport position raised relative to the ground, as otherwise it will be removed during transport Would damage the subsurface and be damaged itself (or wear unnecessarily). On the other hand, they are used in order to be able to exert pressure on the paving material to be compacted, in addition to the compacting elements of the compacting screed designed as rammers or the like and their own weight.

It has been customary in generic road enfertigern ß the piston-cylinder units to be arranged so that its longitudinal center axis of a supporting arm in the working position substantially perpendicular to the connecting line between the two ends, namely to continue so that the piston rods of the piston Cylinder units are extended (essentially completely) in the working position. This arrangement was based in particular on the consideration that a simple arrangement and articulation could be achieved in this way and that the cross-section of the piston rod could be smaller by loading the piston rod. At a certain working pressure, however, only a lifting force was available in the piston-cylinder units to generate the lifting torque, which is only proportional to the piston ring area (= piston cross-sectional area reduced by the cross-sectional area of the piston rod) and not to the piston area.

From US-A-4 313 690 and BE-A-665 365 lifting devices for pavers with a fixed operating position are known, in which the piston rods of the piston-cylinder units are retracted in the working position, so that the generation of the lifting torque entire piston area is available. The piston-cylinder units are arranged below the support arms.

Since a certain (minimum) lifting height is specified in such a road paver and one usually and expediently (already for reasons of cost) does not use telescopic piston-cylinder units, the previously common arrangement of generic lifting devices meant that the piston-cylinder units (sometimes quite considerably) up to above the floor level of the control station. However, this clearly had the consequence that the rotary or Swiveling of the control station was limited accordingly, since a collision of the control station during swiveling with the ends of the piston-cylinder units and their articulation points protruding beyond its floor level had to be avoided.

The present invention has for its object to provide a generic lifting device that does not limit the rotatability or pivotability of the control panel, the arrangements being made so that a large lifting torque can be generated by the piston-cylinder units.

The solution to this problem is according to the invention that the piston-cylinder units are each articulated at one end to the end section of the support arm facing the compaction screed in such a way that they are essentially parallel to this end section in their working position with the piston rod inserted into the cylinder of the concerned Support arm run, and are hinged at their other end via a lever linkage below the lowest pivoting level of the control station on the frame of the paver.

Due to the parallel arrangement to the support arms, the piston-cylinder units can each be arranged closely adjacent to the respective support arm without projecting significantly upwards above it, whereby they are also particularly accessible there and i. a. due to other requirements, there is already a certain space to the underside of the control station. Since they are articulated on the end section of the supporting arm in question facing the compaction screed, and their piston rods are retracted into the cylinders in the working position, so that the entire piston surface has to be pressurized when lifting out, there is a large lifting moment.

The design is expediently such that the piston-cylinder units are each articulated with their cylinder on the relevant arm.

The other end of the piston-cylinder units facing away from the articulation point on the support arm can expediently be articulated in each case on one leg of an angle lifter, which - at a distance from the free end of the relevant support arm - is pivotably mounted on the relevant support arm, the other leg of the angle lever can be hinged to a lever which is articulated at its other end portion to the paver's frame. Last but not least, this construction also leads to an extremely compact design with regard to its vertical extension, which enables the lifting device to be passed over laterally by the operating station.

Preferred embodiments of the present invention are described in the subclaims.

The invention is explained below using an exemplary embodiment with reference to a drawing.

The drawing shows a road paver, designated as a whole by 1, which can be moved with a chassis 2 on a base 3, namely by an operator 4 who is in an operating station 5 which can be pivoted about a horizontal plane 6 about a vertical axis, whereby the horizontal plane 6 thus forms the swivel plane for the control station 5.

The drawing shows the paver 1 with the compaction screed 7 lowered. During work, the compaction screed 7, which is arranged at the rear in the direction of travel (arrow 9), "floats" from the surface 3 'of the subsurface 3 to an essentially through the height of the traction point 11 above the surface 3 '' certain installation height (not shown here) in order to pull off the mix (road building material) accumulated in front of the screed 7 to the desired installation height.

Two tamper knives 8 ensure good leveling and pre-compaction.

For transport, the compacting screed 7, which is fixedly mounted on the pulling / supporting arms 10, 10, is pivoted upward about the horizontal axis of rotation of the pulling rollers 11, 11.

In the drawing, only one pull bracket 10 can be seen because the two brackets 10, 10 are arranged one behind the other, namely that they are articulated at 11 with a pull roller, so that the brackets 10, 10 together the screed 7 in a raised position Swing the transport position.

This pivoting-up, also referred to as “lifting out”, is carried out by means of a lifting device, designated as a whole with 12.

The lifting device 12 has two mutually parallel piston-cylinder units 13, each of which is assigned to a support arm 10, and each at one end (at 14) on the relevant support arm 10 and at its other end (ultimately) on the frame of the Paver 1 are articulated.

The latter articulation does not take place in the illustrated embodiment directly, but indirectly via an angle lever 15 and an articulated link or lever 16, which is articulated at its other free end (at 17) on the frame 18, below which the Swivel plane for the control station 5 forming horizontal plane 6, as can be seen from the drawing.

From the drawing it can be seen that the piston-cylinder units 13, 13, of which only the one on the left in the direction of travel 9 can be seen in the drawing, in each case at the end section 19 of the screed 7 facing relevant support arm 10 are articulated, in each case on an eye 20 which is fixedly connected to the relevant support arm 10 or its end portion 19. Furthermore, it can be seen that the piston-cylinder units 13, 13 each run in the position shown in the drawing essentially parallel to the free end section 19 of the relevant support arm 10, in each case above the support arm 10, each with their cylinder 13 'are articulated on the relevant arm 10, while their piston rod 13''- and thus their other end - is articulated, as already mentioned, on a leg 15' of an angle lever 15 which is at a distance a from the free end 19 of the arm 10 in question at one horizontal pivot axis 21 is mounted on the relevant support arm 10, and its other leg 15 ″ is connected in an articulated manner to the frame 18 via the lever 16 already mentioned, the articulation point 17 of the lever 16 acting as a link on the frame 18 below the lowest rotational or swivel plane 6 of the control panel 5 is located so that the control panel 5 can be freely rotated about its vertical pivot axis.

If the paver 1 is brought from its working position shown in the drawing into the transport position - i.e. the compaction screed 7 is raised ("raised") by means of the lifting device 12 and the support arms 10, 10 - the operator 4 actuates in the usual manner from the driver's bicycle Hydraulic circuit for the piston-cylinder units 13, 13 of the lifting device 12. The pistons which are essentially fully retracted into the cylinders 13 'become full of pressure medium at the end of the respective piston rod 13''on their free end facing away from the respective piston rod 13'' acted upon, and - without being reduced by the piston rod 13 '' acting area - generates a correspondingly large lifting force, which in turn generates a corresponding (lifting) torque about the articulation point 11 of the support arms 10 on the frame 18 and thus about the pivot axis of the support arms 10, 10, the compaction screed 7 then swiveling the support arms 10, 10 upwards is lifted out of its respective cylinder 13 'into the transport position in the direction of arrow 22 with simultaneous extension of the piston rods 13'',13''.

Claims (4)

1. A lifter for a screed assembly (7) of a road finisher (1) having a control cab rotatable or pivotable around a vertical axis, the screed assembly (7) being pivotally connected to an end part of two parallel support arms (10) which extend lengthwise of the road finisher (11) on a long side thereof, each arm (10) being pivotally connected by way of its other end part to the road finisher frame so that the arms (10) can be raised together from a lowered operative position, in which the screed assembly (7) rests on the material to be compacted, into a raised transportation position, a reciprocating actuator (13) for each support arm (10) being disposed above the support arms (10), each actuator (13) being pivoted at one end to the road finisher frame and at its other end to the associated support arm (10), characterised in that the reciprocating actuators (13, 13) are so articulated at one end to the support arm end part (19) facing the screed assembly (7) as to extend in their operative position, with the piston rod (13'') retracted into the cylinder (13'), substantially parallel to the latter end part of the support arm (10), while at their other end each such actuator is pivotally connected by way of a linkage (15, 16) to the road finisher frame below the lowest pivoting plane of the control cab (5).
2. A lifter according to claim 1, characterised in that the actuators (13, 13) are disposed adjacent the support arms (10, 10).
3. A lifter according to claim 1 or 2, characterised in that the actuators (13, 13) are each pivotally connected to the associated support arm (10) by way of their cylinder (13').
4. A lifter according to one or more of the previous claims, characterised in that the other actuator end (13'') remote from the articulation to the support arm (10) is articulated to an arm (15') of a bell crank lever (15) which is pivotally mounted (at 21) - at a distance (a) from the free end (19) of the particular support arm (10) concerned - on such arm, and the other arm (15'') of the bell crank lever (15) is pivotally connected to a lever (16) which by way of its other end part (at 17) is pivotally connected to the road finisher frame (18).

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