DE3232020A1 - DEVICE FOR THE AUTOMATIC CONTROL OF THE PRE-SCRAPER HEIGHT OF A SLIDING PAVER - Google Patents

Description

Device for the automatic control of the pre-cleaner

height of a slipform paver

The invention relates to a device for the automatic control of the pre-scraper height of a slipform paver, which has a pre-cleaner, one at a distance from it, has a pressure plate forming an upper sliding formwork and possibly a vibrating device in the intermediate area.

In the production of concrete pavements using slipform pavers the level of the paving material in the area between the pre-scraper and the pressure plate must be relative narrow limits of, for example, _ + 2 cm around a target value for example, be held 5 cm above the printing plate underside. If the level is too low, the pressure plate cuts too much into the liquid slurry area, so that accordingly less installation material under the pressure plate arrives, which can result in corresponding defects, in particular holes, in the concrete ceiling. Come in addition, that the top layer of the pavement produced in this way has lower strength and to dryness shrinkage tends. Is the level of the paving material, i.e. the layer of slurry above the concrete material in the case of Use of a vibrating device in this area, too high,

so the pressure plate cuts too far below the approximately constant thickness for the given concrete moisture A layer of slurry in the concrete material. The result is that the concrete material getting under the pressure plate too is dry, so that a flat, smooth road surface can no longer be achieved. So far, the level of paving material was regulated by hand that the level constantly observed and lowered the pre-cleaner when the level was too high and the pre-cleaner when the level was too low raised. Experienced specialists had to be made available for this activity. Proved to be particularly problematic manual readjustment in the case of pavement production takes place in two shifts. With this cost-saving Construction method, a top concrete layer is placed on the first sub-concrete layer. When manufacturing this The top layer of concrete is created in the area between the pre-scraper and the pressure plate due to the smaller volume of concrete a slurry layer of smaller thickness, which requires a correspondingly more precise level regulation.

The object of the invention is to provide an automatic control of the pre-scraper height of a slipform paver to enable.

This task is solved by a level sensor in the area between the pre-scraper and the pressure plate for the paving material, a height adjustment drive for the pre-scraper and a control device which determines an actual level compares the paving material with a target level and, in the direction of reducing the level difference, controls the height adjustment drive.

A particularly simple structure of the device then results if this works like a three-point control, with one switching position being the neutral position and the the other two switch positions to the commands "pre-cleaner

raise "or lower the pre-cleaner".

It may prove necessary to change the target level by hand from time to time, especially for adaptation of changing concrete qualities. This is according to the invention a follow-up control is provided with different target level values that can be entered manually.

The invention can also be used successfully with slipform pavers where the concrete is not shaken in the area between the pre-scraper and the pressure plate. In this case, the level sensor can, for example, be a level measuring plate sliding along above the concrete surface include. In the case of the preferred use of the control device in connection with a slipform paver with a vibrating device, the level sensor comprises a floating body element. This shows that above all sludge level of interest.

I ⁿ a particularly preferred embodiment it is provided that the float member is pivoted to the pre-stripper and in that the actual level of the height of a reference point of the float member between the pivot point and the center of lift defined as a which is preferably a distance from the articulation point between 1/4 and 3 / 4, better 1/3 to 2/3, preferably about half the distance between the pivot point and the center of lift. A particular advantage of this arrangement is that the position of the reference point depends not only on the actual sludge level, but also on the respective height of the pre-scraper. The duration of the control signal "lower scraper" generated when the sludge level fluctuation range is exceeded, for example, depends on the one hand on the level of deviation and on the other hand on the pre-scraper movement taking place in the opposite direction. Because of the latter movement

323202Ü

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the result is a well-defined end of said control signal, which is significantly earlier compared to an arrangement in which the center of lift is defined as the actual level. The invention contributes to the it was taken into account that the sludge level change based on a change in the pre-scraper height was only possible with relative long delay of the pre-scraper height change follows.

Preferably, the floating body element consists of a preferably spherical or cylindrical float and a floating body at one end and on the connecting link articulated to the pre-scraper at the other end. Such a floating body with a connecting link is simple to manufacture and mechanically robust.

The simple, mechanically robust structure essential for the rough operating conditions of the slipform paver is promoted by the fact that a reference point with the floating element, possibly the connecting link, connected, preferably articulated measuring rod is provided there, which can be coupled to a three-point switch. A certain switching hysteresis can be provided in the upper and lower of the three switching points.

According to the invention is a on the measuring rod in different Positions along the measuring rod optionally attachable switch actuator intended for the three-point switch, which enables quick and easy setting and readjustment of the target level. It can be provided here that the switch actuating element has a switching lever of the three-point switch is articulated and that the switch actuating element engages around the measuring rod and can be fixed on the measuring rod by means of a locking screw.

It is also proposed that the height adjustment drive comprises at least one preferably double-acting hydraulic cylinder. The hydraulic cylinder preferably engages via a double cylinder linked to the pressure plate. arm lever to the pre-cleaner. The optimum difference in height between the pre-cleaner and the pressure plate is essential regardless of the height of the pressure plate. The permissible swivel range of the hinged on the pressure plate The double-arm lever can therefore be used in a constant small area even with widely differing printing plate heights lie.

It is conceivable that the three-point switch directly has a corresponding hydraulic device for the at least

! 5 controls a hydraulic cylinder. However, it is preferred an electrical control circuit is provided which is connected to the electromechanical three-point switch and controls a hydraulic device connected to the at least one hydraulic cylinder. Such a control circuit can be used with reliable function in case of need change more easily, especially with regard to their control properties.

The invention is described below using a preferred exemplary embodiment explained with reference to the drawing.

It shows:

Fig. 1 is a schematic side view partially in longitudinal direction section of a sliding circuit according to the invention

finisher; and

FIG. 2 shows the detail A of FIG. 1 on an enlarged scale with a simplified hydraulic circuit diagram.

The two figures are purely schematic.

In FIGS. 1 and 2, the subgrade is denoted by 10. on A one- or two-layer concrete pavement 12 is to be erected on this subgrade. For the construction of this concrete pavement 12, auxiliary banquets 14 are first erected on both sides of their longitudinal edges, as indicated in FIG. 1. After the completion of the auxiliary banquets 14 according to DE-OS 30 32 495 these are driven over by a slipform paver, which is generally designated 16. The slipform paver can, however, also run in a conventional manner on rails which are directly on rest on the subgrade. In the example shown, the slipform paver 16 comprises two lateral crawler tracks 18 to drive on the auxiliary banquets 14 or from those placed on them stationary formwork and running rails 44.

The crawler tracks 18 are equipped with rubber cleats 20. At the front end of the slipform paver 16 is a Distributor 22 arranged for the paving material 24, this distributor 22 being perpendicular to the plane of the drawing Fig. 1 performs reciprocating motion. Furthermore, the slipform paver 16 comprises a slipform which consists of a horizontal pressure plate 26 and vertical side formwork, which when using the formwork and Running rails 44 can also be omitted. In the direction of travel in front of the pressure plate 26 are across the width of the resulting pavement 12 distributed, vibrator elements Arranged in the form of so-called vibrator bottles 30, which are inserted into the Immerse the installation material 24 distributed by the manifold 22. Between the vibrator bottles 30 and the distributor 22 a pre-scraper 32 is arranged. As will be explained in more detail below, the height of the Pre-scraper 32 regulated automatically. For this purpose, the pre-wiper 32 is rigidly at one end of a bent one Double arm lever 49 attached to the vertical Front wall 26a of the pressure plate 26 is articulated in the kink area and via a hydraulic cylinder 50, whose Piston rod 52a engages on the other H ^ belende to a

horizontal pivot axis 54 is pivotable.

On the slipform paver 16, a dowel setting device 34 is arranged at the rear end, which in vertikaier Direction is movable up and down and is intended to use / dowels 36 in the road surface 12. in the In the area of these dowels 36, a parting line is cut as a predetermined breaking point in a subsequent operation.

In Fig. 2 is the basic structure of the invention Device for automatic regulation of the pre-scraper height shown. For the sake of simplicity, the distributor 22 is omitted here. The pre-cleaner 32 in In the form of an elongated plate with a lower horizontal longitudinal edge and slightly inclined in the direction of the pressure plate 26 The top edge pushes a mountain of paving material 24 in front of it. The slipform paver according to the invention is suitable for a single-layer ceiling structure (Fig. 1) as well as for a two-layer structure (Fig. 2). In the latter Trap is made on the pre-fabricated first layer 12a cheaper round grain concrete a second layer 12b applied from wear-resistant split concrete in a second work step, which is shown in FIG.

When the paving material is compacted with the aid of the vibrators 30, a particularly water-rich sludge or is formed Slurry layer 56 on the surface of the material 24. The thickness of this slurry layer 56 is predetermined Moisture of the supplied paving material 24 approximately constant. As indicated in Fig. 2, the horizontal underside of the pressure plate 26 approximately at the level of the bottom of the slurry layer 56. In the continuous A certain proportion of the slurry layer 56 moves forward movement of the slipform paver 16 in direction A under the rounded front edge 26b of the pressure plate 26

and thus with the rest of the einiummaterial 24 under the Pressure plate 26. This proportion is essential for a smooth upper ceiling finish. If the proportion of sludge is too low the installation material below the pressure plate 26 is too dry, so that there are holes, pores or the like. In the Road surface. If the proportion of slurry is too high, a top layer of fine concrete forms, which is not the required one Has strength and tends to shrink when dry, causing bumps and cracks. Because, as can be seen from the above, the thickness of the slurry layer on the paving material below the pressure plate 26 from level c of that withdrawn from the pre-scraper 32 Depending on the paving material in front of the pressure plate 26, this thickness can be adjusted by changing the sludge level in front of the Readjust pressure plate 26. The readjustment can be based on the level h of the sludge surface, since the slurry layer 56 in front of the pressure plate 26 is essentially constant with the concrete consistency remaining the same Having thickness d. It can be seen that one can raise the level by raising the pre-scraper 32. To lower the level, the pre-scraper 32 is lowered accordingly. To determine the actual level value A cylindrical float 56 with a horizontal cylinder axis running transversely to the direction of movement A is used 56a, which dips into the slurry layer 56 in the area above the bottles 30. The float 56 is over an approximately horizontal connecting link 58 hinged on the inside of the pre-scraper 32 on this (Pivot pin 60). An approximately vertical measuring rod 62 is in turn articulated on the connecting link 58 and at one point (reference point 64) which is approximately halfway the distance a from the cylinder axis 56 and the hinge pin 60 lies. The upper end of the measuring rod 62 passes through a corresponding bore of a switch actuating element 66; a locking screw 66a, which is radial with respect to the measuring rod axis, allows the switch actuating element to be fixed

ments 66 in different height positions on the measuring rod 62.

On the frame 16a of the slipform paver 16 is an electromechanical one in the area of the upper measuring rod end Fastened three-point switch 68, the switch lever 68a extends horizontally in a central or neutral position and from this position in the vertical plane up to an upper end position and down to a lower one End position is pivotable (indicated by dashed lines or dotted lines in FIG. 2). In Pig. 2 is one of the lever movement the following movable contact 68b is indicated, which is exposed in the middle position of the lever oil 68a, and in the upper end position of the lever touches the fixed contact 70a and in the lower end position of the lever, the fixed contact 70b. The switchover can be similar to the thermostat controls be provided with a stop hysteresis from the middle position to the upper contact position and back. Same thing can also be used when moving to the lower switch position and back to be provided.

The two fixed contacts 70a and 70b are via corresponding Electrical lines 72a and 72b indicated by dash-dotted lines are connected to a control circuit 74. the Circuit 74 controls a four / three-way valve 76 via a control line 78. The two upper connections of the Valve 76 are connected on the one hand to a hydraulic line 80a, which is used for the pressure connection of a hydraulic. pump 82 leads and the other to a return line 80b, which opens into a hydraulic oil reservoir 84. The pump 82 is supplied with pressurized fluid via a line 80c the reservoir 84 supplied. The two lower connections of the valve 76 in FIG. 2 are via hydraulic lines 8Od and 8Oe are connected to the two connections 50a and 50b of the double-acting cylinder 50. One at the

UZU

Piston rod 52a provided in the cylinder interior working piston 52b divides the cylinder interior into two working spaces, with the U planar surrounding the piston rod 52

Working space with the connection 50b and the other with the Ip

Terminal 50a is connected. ^?

In the ** middle position of valve i shown in Fig. 2,

76, the line 80a is connected to the line 80b; the

Lines 8Od and 8Oe, on the other hand, are fed through valve 76 ΐ

locked. The piston 52b can therefore 'move within the \

Do not move cylinder 50 in the axial direction, so that f

accordingly the pre-scraper 32 over the blocked *

Piston rod 52a and the double arm lever opposite the | *

Pressure plate 26 is immobile. ; Now rises from any-> ■ - '■

For some reasons, the level a of the paving material 24 is I

finally slurry layer 56 relative to the printing plate f; ' ¹ 26, the floating body 56 is raised and with this

the measuring rod 62, but about half of the way. ?. <- '

Since the free end of the switch lever 68a of the switch 68 on; _{; i <}

Switch actuator 66 is hinged, pivoted ti

the switching lever 68a corresponding to the measuring rod movement. ο

As soon as the upper end position of the lever 68a is reached, t

switches the switch 68 to, resulting in a closing of the ϊ Contacts 68b and 70a leads. A corresponding signal

is fed to control circuit 74 via line 72a, ^1;

which thereupon from the OCE pump 82 and the valve 76 gebil- [

dete hydraulic device controls in such a way that the advance ΐ stripper 32 is lowered. For this purpose, the valve body of the

Valve 76 in Fig. 2 to the left _i in the corresponding i

Shifted switch position, in d ^ r the line 80a with the [

Line 80d and line SXJbhnit to line 8Oe ver |

are bound. If the pump 82 is not running continuously _f !

this via a line 74a from the circuit 74!

throw in ^ whereupon the corresponding hydraulic pressure Ί

Extending the piston rod 52a caused and thus a

Lowering the pre-cleaner; 52. Since the level h changes accordingly with a relatively long time delay after the start of the lowering of the pre-scraper 32, forms the cylinder axis 56a with respect to the connecting link 58 a momentarily spatially constant pivot axis when lowering the pre-scraper 32. Accordingly, it lowers the measuring rod 62 by half of that which has been covered vertically downwards by the pre-scraper 32

Way down until finally the switch 68 switches back to its neutral central position. It then switches the control circuit 74 returns the valve 76 to the central position shown in FIG. 2, in which the pre-wiper he 32 is stationary relative to the pressure plate 26.

* ^ If the level h is too low and the switch is made accordingly of the switch 68 in its lower end position, the control circuit 74 switches the valve 76 to the third switch position, in which the lines 80a and 80e and the lines 80b and 80d are connected to one another. With the pump running 82 accordingly the piston rod 52a is pushed into the cylinder 50 and the pre-scraper is raised accordingly until finally the switch 68 is switched to its central position via the moving switch rod 62 will.

If it turns out that the selected target level is not corresponds to the optimal level, you can change the target level in a simple manner by turning the locking screw 66a loosens, the switch actuating element 66 moves accordingly and again with the locking hood 66a on the measuring rod 62 fixes. To increase the target level, the switch actuator 66 must be compared to one another attach the lower point of the measuring rod 62 to this; to lower the target level it must Switch actuation element 66 can be moved upwards.

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With the help of the automatic control device described above for the pre-wiper height a, the target height h can be reliably determined with little mechanical effort Maintain in a range of 11 + 2 cm, with a thickness of the top layer 12b of 6 to 7 cm.

The thickness of the lower layer 12b is about 15 cm. As can be seen from the above, the height control is based on the height h / of the reference point 64 as the actual value. Accordingly, the target value is the sum of the target sludge level and the distance t the cylinder axis 56, which forms the center of lift of the floating body 56, from the mud surface. The height h is in turn composed of the thickness c of the actual concrete layer and. the thickness d the liquid slurry layer 56.

In the case of larger lane widths, according to the invention, there is the Possibility of the pre-cleaner in a horizontal direction to be divided into several pre-cleaner parts, each are separately adjustable in height automatically by means of a control device according to FIG.

Claims (1)

“ATENTATORS DiPJC.-ING.'O. $ CSeQC ° K) 2Vw »DlPL.-PhYS. Dr. K. FlNCKE ***** * · ·· »···» · Dipl.-Ing. F. A-Weickmann, Dipl.-Chem. B. Huber Dr.-Ing. H. Liska 8000 MUNICH 86 27.AlIQ. 1982 PO Box 860 820 MDHLSTRASSE 22 TELEPHONE (019) 910352 TELEX 522621 TELEGRAM PATENTVEICKMANN MÖNCHEN Heilit + Woerner Bau AG
Munich 8Ö Device for the automatic control of the pre-scraper height of a slipform paver Claims 1. Device for the automatic control of the pre-scraper height of a slipform paver, which has a pre-scraper, a pressure plate at a distance from this, forming an upper slipform and, if necessary, a vibrating device in the intermediate area,
marked by a level sensor (56, 58, 62) in the area between pre-scraper (32) and pressure plate (26) for the paving material (24), a height adjustment drive (49, 50, 82) for the pre-scraper (32) and a control device (68, 74, 7 6) which a determined The actual level of the paving material (24) is compared with a target level and, in the direction of a reduction in the level difference controls the height adjustment drive. , Device according to claim 1, characterized in that a three-point regulation is provided. 3. Device according to claim 1 or 2, characterized in that that a follow-up control is provided with different setpoint level values that can be entered manually is. 4. Device according to one of claims 1 to 3, characterized characterized in that the level sensor comprises a float element (56, 58). 5. Apparatus according to claim 4, characterized in that the floating body element (56, 58) is articulated on the pre-scraper (32) and that the actual level is the height h ^{} of} a reference point (64). of the floating body element between the articulation point (60) and the center of buoyancy (56a) is set, which is preferably a distance from the articulation point between 1/4 and 3/4, better 1/3 to 2/3, preferably about half the distance of the articulation point Has center of lift. 6. Device according to claim 5, characterized in that that the floating body element consists of a preferably spherical or cylindrical floating body (56) and a connecting link which carries the float at one end and is articulated to the pre-scraper (32) at the other end (58) exists. 7. Apparatus according to claim 5 or 6, characterized by a reference point with the floating body element, possibly connected to the connecting link (58), preferably there hinged measuring rod (62). 8. Apparatus according to claim 7, characterized by a three-point switch coupled to the measuring rod (62) (68). 9. Apparatus according to claim 8, characterized by an on the measuring rod (62) optionally attachable switch actuating element in different positions along the measuring rod (66) for the three-point switch (68). 10. The device according to claim 9, characterized in that that the switch actuating element (66) is articulated to a switching lever (68a) of the three-point switch (68) is. 11. The device according to claim 10, characterized in that the switch actuating element (66) is the measuring rod (62) and can be fixed on the measuring rod by means of a pestle screw (66a). 12. Device according to one of the preceding claims, characterized in that the height adjustment drive at least one, preferably double-acting hydraulic cylinder (50), which preferably over a double-arm lever (49) hinged to the pressure plate (26) engages the pre-scraper (32). 13. The device according to claim 12, characterized in that that an electrical control circuit (74) is provided, which is connected to the electromechanical three-point switch (68) is connected and a hydraulic device (76, 82) controls. 14. Slipform paver with a pre-scraper, one spaced apart from this and forming an upper slipform Pressure plate and possibly a vibrating device in the intermediate area, characterized in that the pre-scraper divided into at least two pre-wiper parts is, each of which is height-adjustable by means of a device according to one of claims 1 to 13.