EP3085832B1 - Device for compacting of the underlying surface - Google Patents

Description

introduction

The present invention relates to a device for compacting a substrate according to the preamble of claim 1.

For the purposes of the present application, a "ground contact unit" is understood to mean a unit which comes into direct contact with the respective substrate to be processed. In a device which is designed as a vibration plate, such a ground contact unit is usually formed by a flat metal plate, which is displaceable by means of a vibration exciter in a vibration.

For the purposes of the present application, a "guiding device" is understood to be a device by means of which the device can be guided, that is, the device can be changed in direction and the device can be pushed and pulled. Known devices of the type described above have an "automatic Gerardeauslauf" in an operating state in which the vibration exciter is active, so that an intervention of the user of the device in the sense of applying a steering movement or the like is usually not necessary. In the sense of the present application, the guide device is in any case one which is operated directly by a user of the device. This means that the guide device does not act in the sense of a remote-controlled guidance.

The mentioned "vibration exciter" is usually an eccentric, which is typically driven by an internal combustion engine. The eccentric generates by means of a movement of a mass about an eccentrically arranged axis a vibration, by means of which at least the ground contact unit is displaceable in the desired vibration.

To some extent the opposite of the "operating state" described here is a "resting state". Under this rest state is understood a state of the guide device in which it is free of external forces. In particular, in the idle state, the guide device of the device is not used and is therefore exposed solely to the weight force acting on its own weight. The buffer unit is thus in a non-deformed state in this resting state Condition before, since a transfer of forces from the guide device does not take place on the superstructure.

A "contacting" surfaces of the bonding means and the buffering unit is understood to mean that these surfaces abut each other so that power flow from the buffering unit to the bonding means and vice versa is possible. For this purpose, it is not absolutely necessary that there is a full-area contact between corresponding surfaces of the buffer unit and the connecting means. Instead, it is also conceivable that only a part of corresponding surfaces of the buffer unit and connecting means are in contact. However, it may be advantageous if there is a full-surface contact between corresponding surfaces of the buffer unit and the connecting means.

A direction, referred to herein as "radial to the axis of rotation", is oriented perpendicular to the axis of rotation of the device. An overlap of the guide device and the buffer unit in the overlap region therefore means that, in the case of an imaginary cut radially to the axis of rotation within the overlap region, both the buffer unit and the guide device are cut. Such Embodiment is not given in the above-mentioned prior art, since the local terminal plate is oriented parallel to an end face of the local buffer unit and arranged on this end face; Consequently, there is no section radially to the local axis of rotation feasible, by means of which both the local connection means and the local buffer unit are cut.

State of the art

Devices of the type described above are already known from the prior art. They are typically used to compact a substrate. This takes place in that the floor contact unit "vibrated", which is set in oscillation, acts on the respective substrate. Due to a mass of the device, the individual particles, of which the substrate is formed, compacted. In this way, it is possible to stiffen the substrate to some extent, so that this yields under a subsequently applied load, such as a building or route to be created on it, only to a reduced extent and there are no unwanted settlements.

In particular from the DE 297 01 737 U1 a device is known whose guide device is connected with the interposition of a buffer unit with the local superstructure. The buffer unit serves to "buffer" a vibration of the superstructure and thus forward only to a reduced extent to the guide device. This is of particular importance inasmuch as an acceleration of the management device should be below 2.5 m / s ² due to occupational health and safety regulations, so that the use of the device is not limited in time. For acceleration values above 2.5 m / s ² , DIN EN ISO 5349 prescribes a time limit for the daily service life of a device. These should be avoided.

To achieve this, the buffer unit of the device known in the prior art is formed of an elastic material, so that it can deform particularly easily. The buffer unit is arranged on the superstructure of the device such that it acts as a kind of intermediate element between the guide device and the superstructure. That is, the guide means and the superstructure are not in direct contact, but forces flowing between the guide means and the superstructure are transmitted in each case exclusively by means of the buffer means.

Although the "buffering" of the vibrations of the superstructure for the reasons mentioned is desirable, it is a fundamentally disadvantageous by this indirect transmission of movements of the guide means on the superstructure in terms of a leadership of the superstructure. The said spongy transmission is due to the elasticity of the buffer unit, which results in a steering movement being exerted on the guide means being transferred to the uppercarriage only in a buffered form. For this purpose, the buffer unit is according to the above DE 297 01 737 U1 designed such that it stiffened upon reaching a certain deformation, so that a more direct or "unfiltered" power transmission between the guide device and the superstructure is possible. It is understood that with this stiffening of the buffer unit and the vibrations of the upper carriage are transferred to an increased extent to the guide device; However, since this usually takes place only over relatively short periods of time, this results in no increased health risk for the user of the device.

In order to ensure a buffering effect of the buffer unit, it is of particular importance that contact between metal and metal is avoided. Because of the high rigidity of metal, such a contact leads namely to an immediate transmission of the vibration of the upper carriage on the guide device. In order to avoid direct contact between metallic parts of the guide device and the superstructure, the buffer unit is vulcanized according to the cited prior art document on a connection plate which is fixed to the superstructure. This connection plate is used exclusively for connecting the superstructure with the buffer unit; a contact between the terminal plate and the guide means does not occur.

The connection plate is arranged on an end face of the buffer unit facing the superstructure. A power flow between the guide device and the superstructure is therefore carried out starting from the guide device in the buffer unit and from there by means of the connecting plate in the superstructure. On the buffer unit acting forces are thus removed by means of torques and shear forces in the connection plate. The introduction of a force from the guide device in the buffer unit is therefore carried out from the connection plate from view in each case outwardly. This type of loading is disadvantageous for the connection of the elastic and comparatively soft buffer unit with the rigid connection plate. In particular, in the edge regions of the connection plate, voltage peaks occur that are detrimental to a durability of the connection between the two parts.

Another example known in the prior art which shows a ring-shaped buffer element results from FIGS U.S. Patents 3,972,637 and 4,113,403 , In particular, the latter document discloses a typical vibrating plate whose guide means is connected to the superstructure using a buffer unit. The buffer unit serves to dampen transmission of vibrations from the uppercarriage to the guide means. However, the construction is disadvantageous insofar as the guide means for the purpose of transferring executives, by means of which the vibrating plate can be steered, is rigidly connected to the superstructure. As a result, a comparatively large transmission of vibrations to the guide device is to be expected.

task

The present invention is therefore based on the object to provide a device available whose connection of the guide device and the superstructure over the prior art is improved.

solution

The underlying object is achieved on the basis of a device of the type described above according to the invention by a device having the features of claim 1. Advantageous embodiments will become apparent from the dependent claims 2 to 14.

The device according to the invention has many advantages. In particular, an improved compared to the prior art power flow between the connecting means and the buffer unit is possible. This is due to the fact that the connecting means extends "along" at least part of a longitudinal axis of the buffer unit, so that an off-center loading of the connecting means, as present in the prior art, is at least reduced. The longitudinal axis of the buffer unit is oriented parallel to the axis of rotation. It is basically irrelevant whether the connecting means extends within the buffer unit or whether it surrounds the buffer unit. In any case, the connecting means not only acts on an end face of the buffer unit, but allows an introduction of a force in the connecting means in a starting from the end face inwardly facing area. The connecting means may in particular be formed by a bolt or a tubular element. Likewise, other embodiments of the connecting means are conceivable. In any case, it is advantageous if the connecting means is formed of a resistant material, in particular of a metallic material. Such a connecting means is particularly well suited to dissipate acting forces in the superstructure. It is understood that such a connection means is better suited than the buffer unit according to the prior art for removing forces acting on the buffer unit from the guide device by means of bending moments and shearing forces.

Another advantage of the device according to the invention is its particularly simple production. In particular, it is not necessary to vulcanize the buffer unit on a connection plate. Instead, the buffer unit and the connecting means may be interconnected by "pushing", that is, by means of a movement of the buffer unit and the connecting means relative to each other in a direction parallel to the longitudinal axis of the buffer unit.

The formation of the ring cross section of the buffer unit is of particular importance for its buffering effect. This is based on the consideration that regardless of the material from which the buffer unit is formed, already by the design of the ring cross-section already a buffering effect can be generated. This is possible in particular in that the ring cross section is not executed as a solid cross section, but as a "resolved" cross section. This is understood as meaning such a cross-section which has at least one recess in relation to a solid cross section or a solid cross section. This means that such a ring cross section is taken from a solid cross section material. This reduces rigidity of the buffer unit or, in other words, increases its elasticity. So it goes without saying that such, with at least one recess, possibly with a plurality of recesses, provided ring cross-section alone due to its geometry has at least a certain buffer effect.

The latter results from the reduced rigidity of the buffer unit. The reduced stiffness in turn means that the natural frequency of the buffer unit or an imaginary unit of buffer unit and guide device decreases. The buffer unit is designed so that its natural frequency is well below the excitation frequency of the vibration exciter. As a result, an excitation of the buffer unit and consequently also of the guide device is substantially avoided; in particular, no amplification of the oscillation of the vibration exciter on the guide device can occur. The shear stiffness of a buffer unit is preferably considerably less than its longitudinal rigidity, in particular by at least the factor 10. The longitudinal stiffness describes that rigidity of the buffer unit which has this radial to the axis of rotation. The shear stiffness refers to the rigidity that the buffer unit has in parallel with the axis of rotation.

For the effect of the buffer unit, it is particularly advantageous if the "exclusive power transmission" between the guide device and the superstructure in the context of the present application during the operating state is not only temporarily, but substantially continuous. An interruption of such an "exclusive" power transmission, for example, occur in that by means of the guide device acting on a horizontal axis torque is to be applied. Such a torque is suitable for lifting the device at an end facing away from the guide device. This may be desired in particular during steering movements. The torque is generally generated by the interaction of two connecting points of the guide device and the uppercarriage, wherein a pair of forces can be transmitted to the uppercarriage by means of these connection points. This pair of forces causes the torque described. Accordingly, in addition to a connection point on which the buffer unit acts, at least one second connection point can be present, against which the guide device can be supported in order to apply the described torque. Upon contact of the guide device with this second connection point, there is at times - typically only briefly - a force transmission between the guide device and the superstructure, which does not take place by means of the buffer unit. This is harmless for the success of the invention.

In an advantageous embodiment of the device according to the invention, the connecting means extends in a direction parallel to the axis of rotation at least over one entire length of the buffer unit. That is to say that in any arbitrary cut through the buffer unit radially to the axis of rotation in each case both the buffer unit and the connecting means are cut. This embodiment has the advantage that a contact surface, which form between the corresponding surfaces of the connecting means and the buffer unit, is maximum. As a result, forces to be transmitted between the buffer unit and the connection means can be distributed to a maximum area. In particular, the buffer unit, which is usually elastic, is consequently exposed to a comparatively low surface pressure. In addition, it is conceivable that the connecting means extends beyond the buffer unit, that is to say projects beyond an end of the buffer unit facing away from the uppercarriage. This can be advantageous insofar as this end of the connecting means projecting beyond the buffer unit can be provided with a fixing element which extends substantially in a direction radial to the axis of rotation. Such a fixing element is adapted to engage positively with an end face of the buffer unit facing away from the superstructure and in this way to block a movement of the buffer unit in a direction away from the superstructure relative to the connecting means. Such a fixing element may in particular be formed by a securing pin which extends radially to the axis of rotation.

Furthermore, it is advantageous if the guide device and the buffer unit overlap in such a way that the connecting means extends into the buffer unit. In such an embodiment, the buffer unit encloses the connecting means at least partially, that is, the connecting means is located to a certain extent "within" the Buffer unit. Preferably, the buffer unit completely encloses the connecting means so that an inner surface of the buffer unit fully cooperates with an outer surface of the connecting means. Here, it is quite conceivable that the connecting means extends beyond the buffer unit, wherein a part of an outer surface of the connecting means is not enclosed by the buffer unit.

With regard to the buffer unit, it may be particularly advantageous if the same is rotationally symmetrical. It follows that regardless of a rotational position of the guide means relative to the superstructure always a constant power transmission between the buffer unit and the connecting means, since a cross section of the buffer unit regardless of the rotational position in each case is the same.

In a further advantageous embodiment of the device according to the invention, the central recess extends over the entire length of the buffer unit. The latter forms around this recess around the ring cross-section, which surrounds the recess circumferentially. This means that in a cut through the buffer unit, in which the recess is also cut, the circumferential annular cross-section is cut twice in total. Such a recess is particularly well suited to receive the connecting means of the upper carriage. A design of the recess over the entire length of the buffer unit is particularly advantageous for manufacturing reasons.

As a cross-sectional shapes for the ring cross-section, in particular a Z-shaped or a W-shaped cross section may be advantageous. These cross-sectional shapes each indicate a shape of the ring cross section in the resting state of the guide means, that is, in a state where the buffer unit is substantially free from external forces and hence undeformed. It has been found that said Z-shape and said W-shape are particularly advantageous for buffering the buffer unit. In particular, such buffer units are relatively easily deformable in a direction radial to the axis of rotation, that is to say that they can be deformed into a deflection position starting from a zero position in which the buffer unit is undeformed. This deflection position is at least achieved when the buffer unit is deformed at least at one point along its annular cross-section such that, as it were, a solid cross-section is formed. In other words, in the deflection position, the above-described recesses of the ring cross-section are completely "compressed", so that at the respective point a reduced cross-section with respect to the ring cross-section in the zero position of the buffer unit is present, which, however, has no recesses.

As a result, the buffer unit stiffened at least at this point of the ring cross-section, since further deformation is not readily possible. Instead, an acting external force now counteracts the material stiffness inherent in the material of the buffer unit, the so-called modulus of elasticity. This means that when a force is exerted on the guide device and consequently on the buffer unit, the buffer unit initially has a low rigidity, but stiffens as soon as it reaches its deflection position. As long as the acting force is not sufficient to deform the buffer device into its deflection position, the buffer unit sets just that force against a comparatively low rigidity, which, as explained above, results from the resolved geometry of the ring cross section. Only when the force reaches an amount which is capable of completely compressing the ring cross-section at one point, the stiffening described occurs. This force is referred to here as "limit force".

This behavior of the buffer unit is desirable inasmuch as it must be possible in any case to transmit significant forces to the device or the superstructure by means of the guide device in order to be able to guide or steer the device reliably. For the introduction of such forces from the guide device in the superstructure, the elastic design of the buffer unit is actually disadvantageous. However, this is necessary for the reasons explained above, to decouple a vibration of the superstructure as effectively as possible from the guide device. The operation described here finds a compromise between the two tasks by stiffening the buffer unit, which of course is accompanied by an increased transmission of vibrations of the superstructure on the guide device, only ever occurs when the device must be steered with the help of large executives. This is usually required only for short periods during the operation of the device, so that the impairment of the guiding comfort of the device is reduced to an insignificant extent.

Furthermore, such an embodiment of the device according to the invention may be advantageous in which the buffer unit has an axial projection on an end face facing the uppercarriage. This axial projection is positioned on the buffer unit in such a way that it faces the superstructure with a lateral end face and rests against the superstructure at least temporarily, preferably continuously, with the same end face. The axial projection extends parallel to the axis of rotation, that is, parallel to a longitudinal axis of the buffer unit. It can be advantageous insofar as a distance between the "actual" buffer unit and the superstructure in any case at least equal to the length of the projection, this has measured in a direction parallel to the axis of rotation. In this context, the term "actual buffer unit" is understood to mean that part of the buffer unit which is used for transmitting forces between the connection means and the guide device. The guide device is usually arranged by means of a metallic coupling means on the buffer unit. As part of a steering movement, at least a portion of this coupling means is moved in a direction parallel to the axis of rotation or rotated about the connecting means, so that at least one end side of the coupling means is moved in a direction toward the superstructure. By means of the projection described it is ensured that a direct contact between the coupling means and the superstructure does not come about, since the projection enforces a certain "free space" between the coupling means and the superstructure. In a described contact of coupling means and superstructure, the metallic coupling means would cooperate directly with the metallic superstructure, wherein a transfer of vibrations from the superstructure on the coupling means and consequently on the guide means directly, that is, without being buffered takes place. This is not desirable for the reasons mentioned above. By means of the projection, the distance between the coupling means or the guide device and the superstructure is now set to a minimum, so that the described contact of "metal on metal" does not occur.

Advantageously, the buffer unit is formed of an elastic material, in particular of an elastomer, preferably of a natural rubber. Such a material is particularly preferable in view of its buffering properties. It is true that the higher the elasticity of the material of the buffer unit causes a better buffering of the vibrations of the superstructure.

It has been found that this elastic material of the buffer unit advantageously has a hardness which is in the range of 25 Shore to 55 Shore, preferably in the range of 35 Shore to 45 Shore. In this hardness range, both a sufficient transfer of forces between the guide device and the superstructure and a settlement of the vibrations of the superstructure fulfilling the requirements explained above are ensured. In particular, the buffer unit is hard enough for the device to be moved reliably by means of the guide device, in particular to be guided laterally.

In a further advantageous embodiment of the device according to the invention, the coupling means, by means of which the buffer unit with the guide means and is coupled in reverse, with the buffer unit from an overlap region. In this overlapping area, the buffer unit and the coupling means overlap in a direction radial to the rotation axis, that is, in a direction perpendicular to the longitudinal axis of the buffer unit, with corresponding surfaces of the buffer unit and the coupling means in contact with each other. The term "overlap" is to be understood in this context analogous to the overlap of the buffer unit with the connecting means. That is, in a cut made in a plane perpendicular to the rotation axis within the overlapping area of the buffer unit and the coupling means, both the buffer unit and the coupling means are cut. By such an embodiment, it is possible to transmit a force applied by the guide means by a combination of a tensile force and a compressive force on the buffer unit and finally on the connecting means or the superstructure. In particular, it is not necessary to transmit the force acting on the guide means by means of bending moments or shear forces on the buffer unit.

In principle, it is not necessary that the overlapping area of the buffer unit with the connecting means and the overlapping area of the buffer unit with the coupling means also overlap. This means that it is fundamentally conceivable that the said overlapping areas are to some extent arranged "next to one another" along the axis of rotation. In such a configuration, the connecting means only extends over a part of the longitudinal axis of the buffer unit, the coupling means extending exclusively in a subsequent region starting beyond one end of the connecting means. Consequently, no cutting guide perpendicular to the axis of rotation or the longitudinal axis of the buffer unit is conceivable, in which all three elements, namely the connecting means, the buffer unit and the coupling means, are cut.

Although the above is conceivable, it is particularly advantageous if a "common overlap region" is formed on the buffer unit, in which the connecting means, the buffer unit and the coupling means overlap. It is understood that a force flow between the connecting means and the coupling means in this way can be at least partially, preferably completely, by means of compressive forces and tensile forces. A power transmission by means of bending moments and shear forces is therefore at least not exclusively, advantageously not at all necessary. It will be appreciated that such an embodiment is particularly preferred in which the overlapping area which the connecting means forms with the buffer unit coincides with the overlapping area which the coupling means forms with the buffer unit, so that the two overlapping areas are completely coincident. In this Case is a power transmission between the coupling means and the connecting means exclusively by means of tensile forces and compressive forces transmitted by means of the buffer unit, possible.

It is particularly advantageous if the coupling means is designed in the form of a sleeve which comprises the buffer unit, this sleeve advantageously enclosing the buffer unit at least essentially, preferably completely. By a "sleeve" is meant a cylindrical element, wherein the cylinder does not necessarily have to be completely closed; Instead, at least one slot may be present, which cuts through the jacket of the cylinder or the sleeve. However, it is particularly advantageous for transmission of forces between the coupling means and the buffer unit when the sleeve is self-contained. The sleeve includes the buffer unit such that the buffer unit is disposed within the sleeve. A force transmission from the sleeve to the buffer unit is effected by means of lateral surfaces of both parts, wherein an outer circumferential surface of the buffer unit cooperates with an inner circumferential surface of the sleeve. A special type of non-positive connection between the sleeve and the buffer unit is not mandatory. It is understood that a relative movement of the sleeve to the buffer unit is conceivable only in a direction parallel to the longitudinal axis of the buffer unit. Due to the contact between the lateral surfaces of both parts, however, results in a frictional engagement, which substantially prevents a relative displacement of the two parts. For this purpose, it may be advantageous if an outer diameter of the buffer unit minimally exceeds an inner diameter of the sleeve or of the coupling means, so that the buffer unit has to be "pressed in" to some extent into the sleeve. As a result, a normal force, which forms between the corresponding lateral surfaces of the buffer unit and the sleeve, artificially increased, which increases in direct consequence, a maximum transferable frictional force.

Furthermore, it may be particularly advantageous if the buffer unit is deformable from a rest state of the guide means by applying a force to the same, wherein a stiffness buffer unit increases with increasing deformation of the buffer unit. This increase in stiffness does not necessarily mean a steady increase. Instead, it is also conceivable that the stiffness of the buffer unit increases abruptly and thus discontinuously after reaching a certain deformation ("limit deformation"). It is quite conceivable that the stiffness of the buffer unit remains constant both before reaching this limit deformation and thereafter. Due to the increase in rigidity, a power transmission between the guide device and the superstructure is improved. In particular, it is with increasing stiffness all the easier to impose a change of direction by means of the guide device of the device. The change in the stiffness of the buffer unit can be effected both by material-specific reasons and by geometrically changing the buffer unit. In particular, by means of the latter, it is particularly easy to conceivably change the rigidity of the buffer unit appreciably with increasing deformation. One way of achieving this has already been explained above on the basis of the specific geometries of the buffer unit or a ring cross-section of a buffer unit. Thus, cavities of the buffer unit can be compressed, in particular due to an increased force, so that an initially "dissolved" cross section of the buffer unit is changed to a solid cross section.

Advantageously, the rigidity of the buffer unit changes from a starting stiffness to a final rigidity, wherein the starting stiffness acts in an undeformed state of the buffer unit and the final rigidity is increased relative to the starting stiffness. Upon reaching the final rigidity, it is particularly easy to transfer forces between the guide device and the superstructure without the buffer unit deformed appreciably further. In this state, a buffering effect of the buffer unit or a decoupling of the guide device from the superstructure is greatly reduced, so that a transfer of vibrations between the superstructure and the guide device takes place to an increased extent. This is not the case in the presence of the starting stiffness of the buffer unit; this is so small that the buffer unit relatively easily deformed under the action of a force and can absorb in this way movements of the connecting means of the upper carriage particularly easy. This results in the desired buffer effect of the buffer unit. Advantageously, the final rigidity of the buffer unit is increased by a factor of at least 10, preferably 20, preferably 30, relative to the starting stiffness.

Furthermore, it may be advantageous for the device according to the invention, when the guide device is formed by a 2-arm drawbar, which is connected at two connection points with the superstructure. Here, each of the two connection points is in each case equipped with a buffer unit, so that the guide device or the drawbar is decoupled from the superstructure. Using a buffer unit having a ring cross-section, which is Z-shaped or W-shaped in the sense of the above explanations, it is particularly advantageous if these buffer units are arranged "mirror-inverted" to each other. Especially with regard to a Z-shaped design of the ring cross-section, this means that a central web of the Z should be inclined to the upper carriage. That means that yourself the center bar, starting from its end remote from the uppercarriage, approaches successively toward its end facing the uppercarriage of the axis of rotation of the guide device. By this type of arrangement of the buffer unit, it is possible to transmit a force acting parallel to the axis of rotation and on the buffer unit by means of a tensile force which forms within the central web of the Z-shaped annular cross section. This is particularly advantageous with regard to steering movements in which the device is steered. A steering takes place by means of the application of a pair of forces on the 2-armed drawbar, which, depending on the steering direction at the joints opposite forces are introduced into the superstructure. Due to the elasticity of the buffer unit, the same will deform under the acting forces, so that the guide device is rotated relative to the uppercarriage. This is in any case associated with an axial movement of the coupling means relative to the connecting means, wherein the buffer unit is deformed accordingly. By means of the central web of a Z-shaped ring cross-section, this deformation of the buffer unit can be removed by a tensile force. The buffer unit itself thus remains essentially in shape.

embodiments

Fig. 1:

eine isometrische Ansicht einer erfindungsgemäßen Vorrichtung,

Fig. 2:

ein Detail einer Verbindungsstelle, an der eine Führungseinrichtung an einen Oberwagen der Vorrichtung angeschlossen ist,

Fig. 3:

einen Querschnitt durch eine erste Puffereinheit,

Fig. 4:

eine isometrische Ansicht der ersten Puffereinheit,

Fig. 5:

einen Querschnitt durch eine zweite Puffereinheit,

Fig. 6:

eine isometrische Ansicht der zweiten Puffereinheit und

Fig. 7:

ein Kraft-Verformungs-Diagramm einer Puffereinheit.

The device according to the invention is explained in more detail below with reference to an exemplary embodiment, which is illustrated in the figures. Show it:

Fig. 1:

an isometric view of a device according to the invention,

Fig. 2:

a detail of a connection point at which a guide device is connected to an upper carriage of the device,

3:

a cross section through a first buffer unit,

4:

an isometric view of the first buffer unit,

Fig. 5:

a cross section through a second buffer unit,

Fig. 6:

an isometric view of the second buffer unit and

Fig. 7:

a force-deformation diagram of a buffer unit.

A first embodiment, in the Figures 1 and 2 is shown, comprises a device 1 according to the invention , which comprises an undercarriage 2 with a ground contact unit 3 and a superstructure 4 . The upper carriage 4 is connected to a guide device 5 , which is designed in the form of a two-armed drawbar. The guide device 5 is connected to the superstructure 4 at two mutually opposite connection points 6 , wherein the guide device 5 is rotatable relative to the superstructure 4 . The connection points 6 are arranged on a common axis, the an axis of rotation 7 of the guide device 5 describes. A rotation of the guide device 5 about the superstructure 4 takes place about this axis of rotation 7, which is aligned horizontally and perpendicular to a main axis of the device 1 . Furthermore, the superstructure 4 has a second connection point 23 , which is arranged at a distance from the first connection point 6 . The second connection point 23 serves to a certain extent as an abutment for the guide device 5, by means of which a supporting force can be received. In practice, it is by means of an interaction of the first connection point 6 and the second connection point 23 to apply a pair of forces on the superstructure 4 and lift it in this way at its front end. This can be advantageous in particular to support a steering movement.

The uppercarriage 4 further comprises a vibration exciter 8, which is formed here by an eccentric, which is drivable by means of a drive unit. By means of an operation of the vibrator 8 , a vibration is generated, which is transmitted to the undercarriage 2 , so that the ground contact unit 3 is vibrated. By means of this vibration of the ground contact unit 3 , a in FIG. 1 not shown underground are compacted.

The guide device 5 is connected with the interposition of two buffer units 9 with the superstructure 4 . For this purpose , the guide device 5 comprises two coupling means 10 which are designed in the form of a sleeve which encloses in each case one of the buffer units 9 . It is understood that the two coupling means 10 are respectively arranged at opposite ends of the guide means 5 and cooperate with each opposite buffer units 9 . Due to the articulated design of the connection points 6 , it is possible to rotate the guide device 5 about the axis of rotation 7 , so that a handle height of the guide device 5 is variable. Otherwise, the guide device 5 is coupled to the superstructure 4 in such a way that compressive forces and tensile forces can be transmitted from the guide device 5 to the superstructure 4 . A power flow between the guide device 5 and the superstructure 4 takes place "through the buffer unit 9 therethrough"; an immediate force transmitting connection between the guide means 5 and the superstructure 4 does not exist. At the moment of a power transmission between the guide device 5 and the superstructure 4 by means of both connection points 6, 23 , it may be possible for a short time that a force flow between the guide device 5 and the superstructure 4 does not take place exclusively by means of the buffer unit 9 . However, this is harmless for the inventive success of a suspension of the vibration of the superstructure 4 on the guide device 5 .

The buffer unit 9 is formed of an elastic material, in particular of a natural rubber. It follows that the buffer unit 9 is elastically deformable under the action of a force, wherein an applied deformation is reversible. That is, after relieving the buffer unit 9, the same goes back to its original form. Plastic deformation does not occur. By virtue of their ability to absorb elastic deformations, the buffer units 9 are capable of buffering vibrations of the superstructure 4 in such a way that they are transmitted to the guide device 5 only to a reduced extent or with a reduced amplitude. This has the particular advantage that an operation of the device 1 - and in particular the use of the guide device 5 - is comparatively pleasant for the respective user, since his arms are only exposed to a reduced vibration on the guide device 5 .

For further explanation of one of the connection points 6 , reference is made to the illustration in FIG FIG. 2 directed. This illustrates both an end of the guide device 5 and one of the coupling means 10. Further, in FIG. 2 a connecting means 11 can be seen that in force transmitting manner is connected to the superstructure 4 . The connecting means 11 is formed here by an elongated, solid metal bolt which is welded to the superstructure 4 . The connection of the connecting means 11 with the superstructure 4 is therefore suitable for transmitting both longitudinal forces and transverse forces and bending moments to the superstructure 4 . The buffer unit 9 has a central recess 12 , through which the connecting means 11 extends. A longitudinal axis of the connecting means 11 coincides with a longitudinal axis of the buffer unit 9 and the rotation axis 7 already described above. It is understood that the buffer unit 9 is formed rotationally symmetrical, wherein an axis of rotation of the buffer unit 9 coincides with the axis of rotation 7 . The connecting means 11 and the buffer unit 9 form an overlapping area in which both parts overlap. The term "overlapping" in this context is to be understood such that a cut guided radially to the axis of rotation 7 intersects both the connecting means 11 and the buffer unit 9 within the overlapping area. In the example shown here, the overlapping area extends from an end face of the buffer unit 9 facing the uppercarriage 4 to an end face of the buffer unit 9 facing away from the uppercarriage 4. In other words, the overlapping area extends over an entire length of the buffer unit 9, which surrounds it in FIG has a direction measured parallel to its longitudinal axis. The connecting means 11 has a length such that it projects beyond the buffer unit 9 on a side of the buffer unit 9 facing away from the uppercarriage 4 . That is, beyond the buffer unit 9 a guided radially to the axis of rotation 7 section is possible, which intersects only the connecting means 11, but not the buffer unit 9 . The recess 12 of the buffer unit 9 has a circular cross section, which corresponds to the cross section of the connecting means 11 . This has the consequence that the buffer unit 9 rests with an inner circumferential surface of the recess 12 on an outer circumferential surface of the connecting means 11 , wherein in the example shown there is a full-surface contact between the mutually facing lateral surfaces.

The coupling means 10 described above is also rotationally symmetrical, wherein the coupling means 10 rests with an inner circumferential surface on an outer circumferential surface of the buffer unit 9 . It is understood that also the coupling means 10 and the buffer unit 9 together form an overlap region, wherein the length of the buffer unit 9 corresponds to a length of the coupling means 10 measured in the direction of the rotation axis 7 : that is, the overlapping area which these two parts form extends over the entire length of the coupling means 10 . Furthermore, the connection point 6 is designed in such a way that the two overlapping areas which are present between the connection means 11 and the buffer unit 9 and between the coupling means 10 and the buffer unit 9 likewise overlap. It follows that a cut guided radially to the axis of rotation 7 in the overlapping area of buffer unit 9 and connecting means 11 equally intersects the overlapping area of buffer unit 9 and coupling means 10 or not only the connecting means 11 and the buffer unit 9, but also the coupling means 10 . This embodiment has the particular advantage that a power transmission between the coupling means 10 and the connecting means 11 can be done completely by means of compressive forces and tensile forces; a removal by means of shear forces and / or bending moments is not necessary. The connecting means 11 then derives these forces by means of bending moments in the superstructure 4 . For this purpose, the connecting means 11 is particularly well suited due to its massive metallic design; In any case, the connecting means 11 is much better suited for such a force removal than the buffer unit 9, which is used according to the prior art for just that force removal.

A rotatability of the guide device 5 to the superstructure 4 and to the connecting means 11 is such that the buffer unit 9 can rotate relative to the connecting means 11 about the axis of rotation 7 . The connection of the buffer unit 9 with the coupling means 10 , however, is designed such that a rotatability of these parts does not take place relative to each other, that is, no between the two parts "Slip" occurs. In order to allow a rotatability of the buffer unit 9 relative to the connecting means 11 , it is not possible to connect these two parts frictionally with each other. In order to ensure, despite such a lack of adhesion, that the buffer unit 9 is not in the axial direction, that is parallel to the axis of rotation 7, "slipping" of the connecting means 11 in one direction, comprises the connecting means 11 is a radial bore. This hole is adapted to receive a fixing element, which in the Figures 1 and 2 not shown. This fixing element can be designed in particular in the form of a securing pin. In any case, the fixing element extends through the radial bore of the connecting means 11 and projects radially over the outer circumferential surface of the connecting element 11 so that it can engage in a form-fitting manner with an end face of the buffer unit 9 facing away from the upper carriage 4 . In this way it is ensured that the buffer unit 9 can not slip sideways from the connecting means 11 .

In the FIGS. 3 to 6 two different variants of buffer units 9 are shown. In the first variant, resulting from the FIGS. 3 and 4 shows, the buffer unit 9 has a ring cross-section 13 which is Z-shaped. Furthermore, the buffer unit 9 comprises an in FIG. 3 Left side shown a projection 14 which projects parallel to a longitudinal axis 15 of the buffer unit 9 via a left end face 16 of the buffer unit 9 . The ring cross-section 13 of the buffer unit 9 has two circumferential recesses 17 , which are formed in the ring cross-section 13 in such a way that the remaining or "standing" material of the ring cross-section 13 forms the characteristic Z-shape. This is characterized in that it comprises two parallel flange portions 18 and an inclined center web 19 . The central web 19 extends from the projection 14 to an opposite end face of the buffer unit 9, wherein a radial distance of the central web 19 from the longitudinal axis 15 of the buffer unit 9 increases steadily. The buffer unit 9 is in the FIGS. 3 and 4 shown in a power-free state in which the buffer unit 9 is undeformed. An introduction of force from the guide device 5 into the buffer unit 9 or into the connecting means 11 immediately causes a deformation of the buffer unit 9, the latter being simultaneously "pressed" and "pulled". It is self-evident that a direction of action of a force acting on the buffer unit 9 is constant, so that the buffer unit 9 is charged exactly opposite to positions opposite relative to the connecting means 11 and is correspondingly deformed.

At a point or at the locations where the buffer unit 9 is subjected to a compressive force, this is compressed, wherein the annular cross-section 13 of the Buffer unit 9 deformed. This deformation causes the circumferential recesses 17 are also compressed at the respective compressed point. This in turn causes the recesses 17 to "disappear" in a sense. Of course, this is only possible as far as possible until the opposing flange sections 18 of the ring cross section 13 lie directly on top of one another in this state, the annular cross section 13 at the corresponding point is consequently reduced to a solid cross section. This has the consequence that the ring cross section 13 then can not deform further in the same way. This requires that the buffer unit 9 stiffened, that is, as a result of an additional Kraftinkrements undergoes a relatively small deformation. This leads to a buffer effect of the buffer unit 9 being considerably reduced. A transmission of vibrations of the superstructure 4 on the guide means 5 is therefore dependent on the state in which the buffer unit 9 is located. In this connection, it should be mentioned that the above-described deformed state of the buffer unit 9, in which the recesses 17 of the ring cross-section 13 are compressed in one place, occurs only under the action of a considerable force. This may be the case in particular if a change in direction is to be impressed by means of the guide device 5 of the device 1 . In this load case, mutually at the joints 6 to a transfer of a considerable compressive force or a considerable tensile force, wherein the coupling means 10 is pressed at the one connection point 6 in the direction of travel of the device 1 and vice versa opposite at the opposite junction 6 in one direction the direction of travel of the device 1 is pulled. As soon as the corresponding ring cross sections 13 of the two buffer units 9 are maximally deformed, a force transmission between the guide device 5 and the superstructure 4 takes place, as it were, directly, which facilitates transmission of a desired steering force. The buffer units 9 are arranged mirror-inverted to each other at the opposite connection points 6 , so that their center webs 19 are aligned in each case concurrently to the upper carriage 4 out. This is advantageous insofar as by means of the central webs 19, a tensile force can be transmitted from the outer flange portion 18 to the inner flange portion 18 . This usually occurs when the buffer unit 9 is loaded in an axial direction away from the uppercarriage 4 . The buffer units 9 are advantageously arranged on the uppercarriage 4 such that the projection 14 faces the uppercarriage 4 . This has the advantage that a lateral end face of the contact means 10, which faces the uppercarriage 4 , does not come into direct contact with the uppercarriage 4 even with a strong deformation of the buffer unit 9 . This ensures that, at most, in exceptional cases, preferably at no time, a "metal to metal" contact between the coupling means 10 and the superstructure 4 comes about.

As an alternative to the buffer unit 9 described above, a further buffer unit 9 'has a W-shaped ring cross section 13' . This differs from the above-described operation z-shaped annular cross-section 13 by the formation of a central web 19 '. This fact does not extend between opposite ends of the opposed flange portions 18 of the ring cross section 13 ', but extends between two corresponding ends of the opposed flange portions 18. In a center portion extending between the flange portions 18, the central web 19' a V Shape up. From the illustration, it can be seen that the annular cross-section 13 ', comparable to the annular cross-section 13, has two circumferential recesses 17' . The mechanism of these recesses 17 ' corresponds to those of the ring cross-section 13; namely, they allow a local compression of the ring cross section 13 ' and thus a transfer of the buffer unit 9 from a "soft state" towards a "stiff state". The advantages of this mode of operation have already been explained above.

In FIG. 7 an exemplary force-deformation diagram 20 is shown, which represents a development of a rigidity of a buffer unit 9, 9 ' under the action of a force. On the x-axis of the diagram 20 , the deformation of the buffer unit 9 and on the y-axis, the force acting on the buffer unit 9 is shown. It can be seen from the diagram 20 that in a starting region in which a force acting on the buffer unit 9 is below a limit force 21 , the buffer unit 9 has a starting stiffness. The starting stiffness is relatively low, as can be seen from the already occurring under the action of small forces large deformations. The limit force 21 represents the force at which the recesses 17 of the ring cross section 13, 13 'are completely compressed. In this state, the buffer unit 9, 9 'has a limit deformation 22 . The achievement of the limit force 21 or the limit deformation 22 has the consequence that the buffer unit 9, 9 ' stiffened abruptly, since a further deformation of the opposing flange portions 18 to each other is no longer possible. The buffer unit 9 consequently has a final rigidity after reaching the limit force 21 or the limit deformation 22 , which considerably exceeds the starting stiffness. It goes without saying that a vibration of the superstructure 4 can be buffered particularly effectively if the buffer unit 9, 9 ' still has its starting rigidity, that is to say is not yet so strongly deformed that the recesses 17 are completely compressed. It is understood that the execution of the buffer unit 9, 9 ' in the above-described variants only is optional; The inventive success is also conceivable using an alternative buffer unit, which has a deformation course not corresponding to the diagram 20 as a function of an acting force. However, it is understood that the load-deflection curve shown in the diagram 20 for an effective buffering of the vibrations of the superstructure 4 is particularly advantageous.

LIST OF REFERENCE NUMBERS

1

device

2

undercarriage

3

Ground contact unit

4

superstructure

5

guide means

6

junction

7

axis of rotation

8th

vibration exciter

9, 9 '

buffer unit

10

coupling agent

11

connecting means

12

recess

13, 13 '

Ring cross section

14

head Start

15

longitudinal axis

16

front

17, 17 '

recess

18

flange

19, 19 '

center web

20

diagram

21

limit force

22

boundary deformation

23

junction

Claims (14)

1. A device (1) for compacting a substrate, in particular a vibratory plate, comprising

   - a lower carriage (2), which has a ground contact unit (3),

   - an upper carriage (4), which is connected to the lower carriage (2) in a force-transmitting manner, and comprises a vibration exciter (8), by means of which at least the ground contact unit (3) of the lower carriage (2) can be set into vibration, and

   - a guidance device (5), by means of which the device (1), at least in an operational state, in which the vibration exciter (8) is active, can be guided on the ground, wherein

   the guidance device (5) is connected to the upper carriage (4), with at least one buffer unit (9, 9') being interposed between, wherein
   the guidance device (5) can be rotated about an axis of rotation (7) relative to the upper carriage (4), wherein
   the buffer unit (9, 9') is connected to the upper carriage (4) in a force-transmitting manner by means of at least one connecting means (11), wherein
   a vibration of the upper carriage (4) can be smoothed out by means of the buffer unit (9, 9'), such that transmission of the vibration of the upper carriage (4) to the guidance device (5) can be reduced at least temporarily, wherein
   the device (1) has an overlapping region, in which the connecting means (11) and the buffer unit (9, 9') overlap radially with respect to the axis of rotation (7), such that corresponding surfaces of the connecting means (11) and the buffer unit (9, 9') are in contact with one another, and wherein
   the buffer unit (9, 9') has a central recess (12) which extends over at least a substantial part of a length of the buffer unit (9, 9'), and parallel to the axis of rotation (7), wherein the buffer unit (9, 9') has an annular cross-section (13, 13') which circumferentially surrounds the recess (12), wherein at least in the operational state of the device (1), a force can be transmitted at least temporarily between the guidance device (5) and the upper carriage (4), exclusively by means of the buffer unit (9, 9'),
   characterised in that,
   the annular cross-section (13, 13') has at least one recess (17), such that the annular cross-section (13, 13') is reduced with respect to a full cross-section in such a way that a stiffness of the buffer unit (9, 9') is reduced with respect to a buffer unit whose annular cross-section is formed by a full cross-section.
2. The device (1) in accordance with claim 1, characterised in that, the connecting means (11) extend in a direction parallel to the axis of rotation (7) over at least an entire length of the buffer unit (9, 9').
3. The device (1) in accordance with claim 1 or 2, characterised in that, the connecting means (11) extend into the buffer unit (9, 9'), such that the buffer unit (9, 9') at least partially, preferably completely, encloses the connecting means (11).
4. The device (1) in accordance with one of the claims 1 to 3, characterised in that, the buffer unit (9, 9') is designed to be rotationally symmetrical about its longitudinal axis (15).
5. The device (1) in accordance with one of the claims 1 to 4, characterised in that, the central recess (12) extends over the entire length of the buffer unit (9, 9'), and parallel to the axis of rotation (7), wherein the annular cross-section (13, 13') of the buffer unit (9, 9') encloses the recess (12) circumferentially.
6. The device (1) in accordance with one of the claims 1 to 5, characterised in that, the annular cross-section (13, 13') is Z-shaped or W-shaped, at least in an idle state of the guidance device (5), in which the latter is free from external forces.
7. The device (1) in accordance with one of the claims 1 to 6, characterised in that, the buffer unit (9, 9') has an axial projection (14) on an end face (16) facing towards the upper carriage (4), wherein the buffer unit (9, 9') preferably bears against the upper carriage (4) with an end face of the projection (14).
8. The device (1) in accordance with one of the claims 1 to 7, characterised in that, the buffer unit (9, 9') is formed from an elastic material, preferably from an elastomer, more preferably from a natural rubber.
9. The device (1) in accordance with claim 8, characterised in that, a hardness of the material of the buffer unit (9, 9') lies in the range from 30 Shore to 50 Shore, preferably in the range from 35 Shore to 45 Shore.
10. The device (1) in accordance with one of the claims 1 to 9, characterised in that, a coupling means (10), by means of which the buffer unit (9, 9') is coupled to the guidance device (5), forms with the buffer unit (9, 9') an overlap region, in which the coupling means (10) and the buffer unit (9, 9') overlap radially with respect to the axis of rotation (7), such that corresponding surfaces of the buffer unit (9, 9') and the coupling means (10) are in contact with one another.
11. The device (1) in accordance with claim 10, characterised in that, the coupling means (10) is designed in the form of a sleeve surrounding the buffer unit (9, 9'), which encloses the buffer unit (9, 9') at least substantially, preferably completely.
12. The device (1) in accordance with one of the claims 1 to 11, characterised in that, starting from an idle state of the guidance device (5), in which the latter is free from external forces, the buffer unit (9, 9') can be deformed by the exertion of a force on the guidance device (5), wherein a stiffness of the buffer unit (9, 9') increases with increasing deformation of the buffer unit (9, 9').
13. The device (1) in accordance with claim 12, characterised in that, a stiffness of the buffer unit (9, 9') alters from an initial stiffness, which the buffer unit has in an undeformed state, to a final stiffness, after reaching a limiting deformation (22), wherein the final stiffness is higher than the initial stiffness.
14. The device (1) in accordance with one of the claims 1 to 13, characterised in that, the guidance device (5) is formed by a two-armed drawbar, which is connected to the upper carriage (4) by means of two connecting points (6), wherein the device (1) comprises a total of two buffer units (9, 9'), one of which acts at each of the two connecting points (6).

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