GB2080374A

GB2080374A - Apparatus for Levelling a Surface

Info

Publication number: GB2080374A
Application number: GB8102599A
Authority: GB
Original assignee: WALO BERTSCHINGER AG
Current assignee: WALO BERTSCHINGER AG
Priority date: 1980-07-22
Filing date: 1981-01-28
Publication date: 1982-02-03
Also published as: GB2080374B; FR2487397A1; FR2487397B1; DE3036234A1; CH647828A5; DE3036234C2

Abstract

Levelling apparatus comprising a smoothing board (51) suspended swingably on two pairs of pivotably interconnected struts (52, 53). The pairs of struts (52, 63) are pivotably connected by means of pivot pins (55, 56) to brackets (57, 58) secured to the smoothing board (51), the brackets being provided with slots (59, 60) at right angles to the board face (51a). A strut (52) also comprises a slot (61) in its longitudinal direction. The struts (52, 53) are also pivotably connected to a pair of rocking levers (54) themselves articulated to a trolley (44). An endless drive with a chain (47) for the trolley (44), and a vibrator drive (66) with eccentric and connecting rod (67) causes the smoothing board (51) to carry out a laterally guided oscillating movement composed of two individual movements which are at right angles to one another. Through the freely mobile swingable suspension arrangement the smoothing board works only in the region of the cement slurry and produces a smooth surface on a concrete slab put down by a finisher and evened-out as regards irregularities without the roughness having to be evened-out subsequently. The apparatus is intended for use more particularly with sliding-shuttering concrete finishers. <IMAGE>

Description

SPECIFICATION Apparatus for Levelling a Surface The present invention relates to an apparatus for levelling a surface, in particular a concrete surface.

Irregularities in the height of a surface may have unpleasant effects, more especially on roadways, since owing to wheels having spring suspension systems, vehicles travelling over frequently repeated similar undulations may have oscillations induced in them which in particular speed ranges may change to resonance vibrations, so that the vehicles are no longer controllable.

Therefore, in the case of conventional finishers for roadway cbnstruction, which are provided with a distributing screw for uniform spreading of the material for the covering layer for the roadway, a vibrator for thoroughly mixing the material, a pressure operated stripping device for forming the concrete, and an end smoother, a special longitudinal smoothing arrangement has been provided for evening-out the irregularities with after-treatment of the concrete deck or covering layer, although such an arrangement can only be used with a specially controlled construction system. An after-treatment facility machine of this kind is described for example in Swiss A 547 916. This machine is mounted on a chassis and is provided with a motor-driven hammer with a cutting head.By means of sensing devices the height differences between a portion of the roadway surface directly below the hammer or immediately before the hammer in the direction of movement, and the portion of the chassis situated above this portion of the roadway surface are sensed and the hammer is operated by means of a control arrangement when the height difference is smaller than a preset value.

Whereas such machines are used more particularly for dealing with crude or rough irregularities in concrete covering layers, these can be evened-out nowadays by swing boards on the finishers and with the use of much more accurate electronic control systems. Present-day known longitudinal smoothers for evening-out small irregularities are used exclusively with finishers using fixed shuttering, and it is known that the surfaces obtained therewith do not meet many present-day requirements, more particularly as regards the construction of aircraft runways, since with them there remains a residual surface roughness of 4 mm and more. This roughness then has to be ground-off with grinding apparatus in laborious and expensive operations.

Therefore, an object of the invention is to provide an apparatus with which the roughness is already smoothed-out to a satisfactory extent during the formation of the concrete slab without any subsequent additional treatment being required, and more particularly an apparatus is to be provided which is suitable for use in slidingshuttering finishers.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a side view of a slidingshuttering finisher with a longitudinal smoother according to this invention; Figure 2 shows a plan view of the slidingshuttering finisher shown in Fig. 1; Figure 3 shows a rear view of the longitudinal smoother according to the invention, and Figure 4 shows a side view of the longitudinal smoother shown in Fig. 3.

The sliding-shuttering finisher 10 is shown in Figs. 1 and 2 comprises a supporting frame 20 with hydraulic drive units 21, a control or driving cab 22, drives 23 for crawler tracks 24, and electronic control arrangement 25 for level and travel direction. For distributing the fresh concrete there are provided two distributing screws 32, 33 driven by individual drives 30, 31. Following these screws there is provided an internal vibrator 34 for homogenising the concrete. A vertically adjustable pressure plate 35 is used for compacting the concrete.

Between the distributing screws 32, 33 and the internal vibrator 34 there is also situated a retaining wall. Following the pressure plate 35 in this example there is also arranged a peg-setting unit 36 with a drive. A swing board 37 which serves for evening-out irregularities in the surface can be adjusted vertically by means of two hand wheels 38.

A transverse beam 43 is supported on two cantilever arms 40, 41. A hydraulic drive 42 and a travelling carriage or trolley 44 driven along the transverse beam 43 are provided on this transverse beam 43. The trolley 44 serves for displacement of a smoothing board 51 of a longitudinal smoother 50 transversely over the concrete slab.

The smoothing board 51 is suspended by means of two pairs of struts 52, 53 on a pair of' rocking levers 54 in such a manner as to be longitudinally and laterally movable. The strut pairs 52, 53 are pivotably connected by means of pivot pins 55, 56 to brackets 57, 58 secured to the smoothing board 51 (for example by welding) at regions adjacent the ends of the board 51.

Through slots 59, 60 in the brackets 57, 58 in the direction at right angles to the working face 51 a of the smoothing board 51 and at least one slot 61 in the one strut 52 in the longitudinal direction of the strut, the smoothing board is given lateral freedom of movement so that it can adjust pivotably through an angle a in relation to a central axis. The slot 61 in the strut 52 also allows movement of the smoothing board through a specific angle in the longitudinal direction.

The strut pairs 52, 53 are connected by a pivot pin 62 to a pair of rocking levers 54. But whereas the two pairs of struts 52, 53 are in each case not connected to one another, so that each individual strut can move by itself the rocking levers of the pair of levers 54 are held together rigidly by a bracing arrangement 63. The rocking levers are connected at their end by a tubular pivot element 64, and the pair of rocking levers 54 is pivotably connected to the trolley 44 by means of a pivot pin 65. An eccentric drive 66 using a connecting rod 67 brings about a rocking movement for the smoothing board 51.

The trolley 44 is guided by a pair of wheels 45 and a pair of supporting wheels 46 in rails 49 of the transverse beam 43. Situated above the arm 41 is the hydraulic drive 42 of the longitudinal smoother 50 with a control valve 70 for a chain drive motor 71 for the chain 47, and on the trolley 44 a control valve 72 is provided for the eccentric drive 66. The chain drive motor 71 is a nonreversible hydraulic motor, so that the chain constitutes an endless drive. Connection between the chain 47 and the trolley 44 is effected by an entrainment pin 48 and a guide groove 73 in a guide plate 74.

It is known that in accordance with the water added and the concrete mix a cement slurry forms behind the swing board 37 and is distributed over the entire concrete covering layer. The longitudinal smoother 50 according to the invention conducts the. smoothing board 51 over this cement slurry in two directions of movement at right angles to one another transversely over the concrete covering layer. The rotational speed of the chain drive motor 71 is adjustable in an infinitely variable manner from 0 to 20 r.p.m. and the rotationai speed of the vibrator drive 66 is adjustable likewise in infinitely variable manner from 0 to 60 r.p.m. Because of the freely swingable suspension of the smoothing board 51 the latter can adjust itself in freely mobile manner relatively to relatively large corrugations in the concrete covering layer, but relatively small unevennesses are evened-out to such an extent that after-treatment of the finished concrete covering by grinding or the like is not necessary.

In this way considerable savings as regards working time and machine costs can be made by using the longitudinal smoother in accordance with this invention.

The longitudinal smoother 50 has been described in connection with a sliding-shuttering finisher. The same longitudinal smoother could also be used with a finisher with normal shuttering or, independently, of a finisher, as an independent working machine.

Claims

1. Apparatus for levelling a surface comprising an elongate smoothing board (51) secured at holders in the region of its two longitudinally remote ends and supported by means of two pairs of struts (52, 53) on a bearing (64, 65) at least approximately above its geometric centre point, and means (43, 44, 54, 66) for moving the smoothing board to and fro in a direction at right angles to its longitudinal axis and imparting an oscillating movement to the board about its longitudinal axis.

2. Apparatus according to Claim 1 , wherein thWe holders are two brackets (57, 58) secured on the smoothing board (51) with openings each for accommodating a pivot pin (55, 56) connecting the pairs of struts (52, 53) pivotably to the brackets.

3. Apparatus according to Claim 2, wherein the openings are slots whose longitudinal axes are situated at right angles to the board face (51 a).

4. Apparatus according to Claim 3, including at least one pair of struts (52) with a slot (61) aligned in the longitudinal direction of the struts and that the pivot pin (56) is slidably arranged in this slot.

5. Apparatus according to Claim 1, wherein the bearing (64, 65) is secured on a trolley (44) adapted to travel over the working width of a finisher on at least one rail (49).

6. Apparatus according to Claim 5, wherein the two pairs of struts (52, 53) are pivotably secured to one another and to a rocking lever (54), for pivoting movement together with said lever at the end regions which are remote from the holders at the brackets (57, 58), and that the rocking lever is pivotably secured on the bearing (64, 65).

7. Apparatus according to Claim 6, wherein the rocking lever (54) is connected at one point on its length with a connecting rod (67) of an eccentric drive (66).

8. A method for operating the apparatus according to Claim 1, characterised in that the smoothing board (51) is moved to and fro regularly and continually transversely to its longitudinal extent whilst at the same time carrying out an oscillating movement in the direction of its longitudinal extent.

9. A method according to Claim 8, characterised in that the movement of the smoothing board is effected at a location behind a finisher at which the aqueous cement slurry covers the covering layer surface at least partially