DE29700741U1 - Base plate for a plate compressor - Google Patents

Description

PATENT ATTORNEYS !SI*:: \ ' *·*\ DIPL.-ING. R. LEMCKE

DR.-ING. H. J. BROMMER DIPL.-ING. F. PETERSEN DIPL.-ING. D. BLUMENROHR

BISMARCKSTRASSE 16 76133 KARLSRUHE

TELEPHONE (07 21) 91 28 00 FAX (07 21) 2 11 05

14 January 1997 16 807 (Bra/gr)

Description

The invention relates to a base plate for a plate compactor, which performs an approximately vertical oscillating movement to compact the soil and which has compaction surfaces on its underside at different levels, with at least one recessed compaction surface in the form of an indentation being present.

Base plates in plate compactors are usually set into vibration so that the soil underneath is compacted by the pressure exerted on it. Vibrations here mean any kind of movement that exerts pressure on the subsoil to be compacted. Base plates of the above-mentioned form are known, for example, from EP-A-93301218.9. This describes a plate which has two compaction surfaces on its underside at different levels, which act in such a way that both compaction surfaces act on the soil for pre-compaction and the large surface area of the base plate prevents the plate compactor from digging into the subsoil. During final compaction, the soil is already so strongly compressed that the plate compactor only touches the soil with the lower of the two compaction surfaces. This significantly increases the compaction pressure per unit area, so that a high final compaction can be achieved without attaching additional weights to the plate compactor.

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The design has the major disadvantage that it reacts extremely insensitively to the gradually increasing compaction of the soil, since only either the entire surface or the protruding surface has a compacting effect. This binary compaction mode creates an inhomogeneous compaction of the soil, which results in unsatisfactory compaction quality, which manifests itself, for example, in the tension of different areas of the soil against one another. This can lead to cracks in the compacted soil if there are temperature fluctuations.

Furthermore, due to the fixed level difference between the two compaction surfaces, this plate is not equally suitable for all types of material and filling heights. The area ratio is fixed; this can cause damage due to over-compaction or, with very high filling heights, optimal compaction cannot be achieved.

The present invention is based on the object of increasing the compaction quality of the soil without losing the cost-effective production and easy handling of the previously described embodiment according to the prior art.

This object is achieved according to the invention in that the recessed compaction surface is curved and/or inclined in relation to the horizontal in its majority.

The curvature and/or inclination prevent the abrupt transition between the pre-compaction phase and the final phase. Instead of the two-stage compaction behavior described at the beginning according to the state of the art, there is now a continuous transition, whereby as the degree of compaction of the underlying soil increases, the contact area between the compaction surfaces of the base plate and the soil continuously decreases and the contact

pressure can be increased significantly without causing edge marks and undesirable tipping movements. This significantly improves the homogeneity of the compaction and reduces the tendency of the tamper to tip, which prevents the disadvantages mentioned at the beginning of the state of the art. On the other hand, the device is still very simple to manufacture and handle, since, for example, there is no need to use additional weights. Furthermore, the design according to the invention still has excellent traction and climbing ability due to the indentations that are also present here.

In the simplest case, the recessed compaction surface can be designed as a concave surface extending continuously across the central region.

However, several recessed compaction surfaces can also be provided at a distance from one another to form further protruding compaction surfaces. In this case, a particularly continuous and homogeneous compaction is achieved through the rapidly changing sequence of recessed compaction surfaces and protruding compaction surfaces, even in a local area of the soil.

The recessed compaction surface can be manufactured very easily and inexpensively in the form of a rib in the base plate. Several recessed compaction surfaces are then designed as several ribs, which conveniently run parallel to one another.

The best traction and the associated highest climbing ability are achieved when the recessed compaction surface runs essentially perpendicular to the direction of travel of the plate compactor. Then the compaction surface supports itself with one of its

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Vertical sides rest on the ground in a form-fitting manner. It is useful if protruding and recessed compaction surfaces run across the entire width of the plate.

The effect according to the invention is particularly effective when the recessed compaction surface is located in the most effective area of the base plate of the plate compactor, i.e. approximately in its middle.

Another very significant advantage arises when the underside of the plate bends upwards outside the area of the indentations towards the front and rear edges of the plate. This bending significantly improves the climbing ability of the plate compactor, as it reduces the risk of digging into the side downhill and the pressure of the plate compactor is always transferred vertically to the soil to be compacted by the bending end area of its base plate, even when the device is tilted. These criteria are met particularly well when the bend is continuous, preferably convex.

Further features and advantages of the invention will become apparent from the following description of several embodiments with reference to the drawings, in which:

Figure 1 shows a first embodiment of a base plate in the

side view;

Figure 2 the same embodiment from below;

Figure 3 shows a second embodiment in side view;

Figure 4 the same embodiment from below;

Figure 5 shows a third embodiment in side view;

Figure 6 the third embodiment from below;

Figure 7 shows a fourth embodiment in side view; and Figure 8 shows the fourth embodiment from below.

In Figure 1 you can see the essentially rectangular base plate 1 of a plate compactor. It has several compaction surfaces 2, 3, 4 on its underside that follow one another in the direction of travel. The protruding compaction surfaces 2 form a vertex plane, from which the compaction surface 3 recedes, so that the compaction surfaces 2 and the compaction surface 3 are at different levels. The compaction surface 3 has the shape of an indentation, to which are connected raised compaction surfaces 2 at the front and back. If the soil is still very loose at the start of compaction, all compaction surfaces will act on the soil during compression. This gives the plate compactor a very large contact surface and prevents the base plate from digging into the subsoil. In the final phase of compaction, the soil is then compacted to such an extent that essentially only the protruding compaction surfaces 2 come into contact with the soil. A very high pressure is then exerted on the subsoil via these relatively small areas, so that a correspondingly high final compaction can be achieved.

It is now essential that the recessed compaction surface 3 is harmoniously curved in its majority from the horizontal. This ensures that the area of the surface of the base plate 1 that acts on the ground continuously decreases during the compaction process. This continuous decrease has the decisive advantage that the homogeneity of the compaction of the ground is significantly increased. This avoids sharp transitions between areas that are very highly compacted and areas that are only slightly or not compacted at all, as is the case with the current technology. Therefore, the compaction is of a higher quality and is therefore more resistant to temperature fluctuations, subsidence, etc. Furthermore, the rammer is

Transitions better suited for different materials and filling heights.

The protruding compaction surfaces 2 are connected to bends 4 at the front and rear, which run upwards relative to the apex plane of the base plate 1. These bends ensure that the plate compactor does not dig into the ground with its front or rear edge even when positioned at an angle, but rather comes to rest securely on a sufficiently large area of the surface of its base plate.

In Figure 2, the division of the base plate into the individual compaction surfaces 2, 3, 4 can be clearly seen again. In particular, it can be seen that both the recessed (3) and the protruding compaction surfaces (2) extend over the entire width of the base plate, so that the soil can be compacted easily on both sides along adjacent lateral edges, walls or the like.

In the second embodiment according to Figure 3, several recessed compaction surfaces in the form of indentations 3a are formed in the base plate of the plate compactor. Here, too, it is important that there is a continuous transition between the use of a very large surface of the base plate in the initial stage of compaction work on the one hand and the transfer of very high pressures per unit area through the protruding compaction surfaces 2 in the final stage on the other. For this purpose, the recessed compaction surfaces 3a have slanted flanks with an inclination of < 45°. Their triangular shape in cross section results in particularly good traction of the plate compactor.

Furthermore, in the embodiment according to Figure 3, the homogeneity of the compaction is increased by the sequence of several protruding and recessed compaction surfaces, since during

a sequence of vibration processes, protruding compaction surfaces 2 and receding compaction surfaces 3a act on the same areas of the soil in rapid, constant alternation.

The upwardly extending, convex bends 4 of the underside of the base plate 1 outside the area of the bulge 3 towards the front and rear edge of the plate again have the same advantages as those already described in Figure 1.

Figure 4 also clearly shows the sequence of the individual compaction surfaces on the underside of the base plate 1 for this embodiment. The recessed compaction surfaces 3a are in total almost as large as the protruding compaction surfaces 2.

The third embodiment according to Figures 5 and 6 corresponds to the second embodiment, except that here the recessed compression surfaces are designed as concave curvatures 3b.

The last embodiment example, as shown in Figures 7 and 8, has four recessed compaction surfaces in the form of grooves 3c. In cross-section, they have the shape of right-angled triangles with an approximately vertical side, which means that at least two of them can be supported particularly well in the subsoil when the plate compactor is pushed off the ground, which involves a propulsion component. This again provides a traction advantage. In its other design, the base plate 1 corresponds to the examples already explained above and therefore also has the advantages described there.

Claims (10)

PATENT ATTORNEYS I &idiagr; I ' III * "II DIPL.-ING. R. LEMCKE DR.-ING. H. J. BROMMER DIPL.-ING. F. PETERSEN DIPL.-ING. D. BLUMENROHR SISMARCKSTRASSE 16 76133 KARLSRUHE TELEPHONE (07 21) 31 28 OO FAX (07 21) 2 11 OS 14 January 1997 16 807 (Bra/gr) Protection claims 1. Base plate (1) for a plate compactor, which carries out an approximately vertical oscillating movement to compact the soil and which has compaction surfaces (2, 3, 3a, 3b, 3c) on its underside at different levels, with at least one recessed compaction surface 3 in the form of an indentation, characterized in that the recessed compaction surface (3, 3a, 3b, 3c) is curved and/or inclined in its predominant part relative to the horizontal. 2. Base plate according to claim 1, characterized in that the recessed compaction surface (3, 3b) is concavely curved upwards. 3. Base plate according to claim 1, characterized in that several recessed compaction surfaces (3a, 3b, 3c) are arranged at a distance from one another to form further projecting compaction surfaces (2). 4. Base plate according to claim 1, characterized in that the recessed compaction surface is formed by a groove (3a, 3b, 3c). 5. Base plate according to claim 3 and 4, characterized in that several grooves (3a, 3b, 3c), in particular parallel to one another, are provided. 6. Base plate according to claim 1, characterized in that the recessed compaction surface (3, 3a, 3b, 3c) runs essentially transversely to the direction of travel of the plate compactor. 7. Base plate according to claim 1, characterized in that the recessed compaction surface (3, 3a, 3b, 3c) runs across the entire width of the plate. 8. Base plate according to claim 1, characterized in that the recessed compression surface (3, 3a, 3b, 3c) is arranged in the central region of the base plate 9. Base plate according to claim 1, characterized in that the underside of the base plate 1 bends upwards outside the area of the recessed compaction surface (3, 3a, 3b, 3c) towards the front and rear edge of the plate. 10. Base plate according to claim 9, characterized in that the bend (4) is continuous, preferably convex.