EP2743400B1 - Vibration tamper - Google Patents

Description

The invention relates to a vibration rammer for soil compaction.

A generic vibration tamper comprises a superstructure with a drive motor and a guide bracket mounted on a machine frame, a substructure with a tamper base driven by the drive motor with a tamper plate and with a drive train via which a drive connection between the drive motor and the tamper foot is produced in such a way that the rammer foot is movable relative to the superstructure along a ramming axis with at least one compression amplitude. A generic vibration tamper is for example from the DE 201 05 768 U1 the assignee, the disclosure of which is hereby incorporated by reference. In this vibratory ramming the drive motor is connected on the output side via a connecting rod with the padfoot and sets a rotational movement of the output shaft of the drive motor in a linear motion or pitching movement of the padfoot to. Vibration tampers are usually assigned to the so-called hand-held "walk behind" machines. For this purpose, the vibration tamper as parts of the superstructure on a usually elastic damping elements mounted on the machine frame guide bracket. The machine frame is essentially a one- or multi-part support structure, in particular for the drive motor and / or the guide bracket of the superstructure. The measures to concretely bring about such vibration damping are generally known in the art. For example, suitable rubber bearings or similar vibration damping devices can be used for this purpose. An essential feature of the damping elements used is that they completely eradicate incoming vibrations from the machine frame into the damping element or merely pass it on to the other side in a damped manner. During operation, an operator can manually guide the vibratory rammer over the guide rail of the superstructure over the surface to be compacted. Generic Vibrationsstampfer are further example of the DE 10 2009 017 209 B4 . DE 10 2010 046 820 A1 and DE 10 2010 047 943 A1 the applicant known. These documents are hereby also incorporated by reference with regard to the structure and operation of generic vibration tampers.

In the vast majority of the drive motor generic vibration tampers are internal combustion engines that provide the required mechanical energy for the operation of the vibratory tamper for soil compaction by the combustion of gasoline or diesel. On a construction site usually numerous existing machines lead to a not inconsiderable exhaust pollution for the persons working on the construction site. The problem here is in particular the regularly occurring high carbon monoxide concentrations and the possibly occurring soot load. This problem is particularly evident when a vibratory rammer is used where only a limited working space is available, only small areas must be compacted and / or selective compaction measures are desired, such as in trench and sewer construction. From the DE 2 226 689 A1 is a liquid gas operated vibrating plate known, which pollutants are reduced in exhaust gases. Alternatively, from the DE 10 2011 105 899.4 the Applicant known a powered with electrical energy Vibrationsstampfer. In particular, however, the necessary rechargeable batteries are still relatively high priced and the operating intervals thus achievable comparatively short. A further fundamental challenge in the development of vibration tampers is also to enable safe and reliable operation despite the naturally occurring high vibration load during operation.

The object of the invention is therefore to provide a vibratory rammer, which allows a comparatively low-emission operation and at the same time is economical to manufacture and also capable of carrying out comparatively long service intervals.

The solution of the problem is achieved with a Vibrationsstampfer according to the independent claim. Preferred developments are specified in the dependent claims.

An essential basic idea of the invention lies first of all in providing the drive energy required for the working operation of the vibratory rammer by means of a drive motor powered by liquid gas. LPG is also commonly referred to as LPG ( liquefied petroleum gas ) or LPG. Liquefied petroleum gas consists essentially of the main components propane and butane, where the respective proportions can vary. Liquefied gas is a gaseous combustible gas in the normal state, which is already at a temperature of 20 ° C under a Let pressure of 8 bar liquefy. A liquid-gas-driven drive motor is accordingly understood to mean a drive motor whose fuel is vaporized liquid gas which, in a combustion process in the drive engine, causes the expansion processes typical for internal combustion engines. Liquefied gas has the advantage that it burns more uniformly and almost soot-free in the combustion chamber of the drive motor compared to the previously regularly used fuels diesel and gasoline. In addition, the carbon monoxide content of the exhaust gas is much lower. In order to supply the drive motor with fuel, a gas supply line according to the invention is also provided, via which liquid gas evaporated to the drive motor can be fed. According to the invention, it is further provided that at least one storage container for storing liquefied petroleum gas is present on the vibratory rammer, so that a supply of liquefied gas can be carried along with the vibrating rammer during operation. The at least one reservoir is thus connected to the gas supply line or a line system on Vibrationsstampfer and supplies the drive motor with LPG. This reservoir is thus generally a pressure vessel, stored in the liquefied petroleum gas in the liquid state and can be carried along with the vibrating rammers in working mode. The reservoir is thus a liquefied gas tank. The line system is generally designed in such a way that it establishes a fluidic connection between the drive motor and the reservoir in order to allow a gas-tight transfer of the liquefied gas from the at least one reservoir to the drive motor while the drive motor is running. For this purpose, the line system comprises suitable pipe and / or hose lines and corresponding connection means to the reservoir and to the drive motor.

The at least one storage container according to the invention is further arranged on the superstructure of the vibratory rammer. This arrangement is advantageous in that, for example, the mechanical loads on the superstructure are much lower than on the substructure. In addition, it can be achieved in an advantageous manner, a spatial proximity between the at least one reservoir and the drive motor.

It is possible that the at least one storage container is fixedly arranged on the superstructure of the vibration rammer. A filling of the at least one reservoir is thus in this case directly to the vibratory tamper. In order to enable the most autonomous operation of the vibratory rammer, it is inventively provided that the at least one reservoir is arranged interchangeably on the superstructure and on the guide bracket of the superstructure of the vibratory rammer. For filling an empty storage container can then be easily replaced or replaced by a full reservoir so that, for example, the downtime of the vibratory rammer can be significantly reduced.

For connecting the at least one storage container to the superstructure of the vibration rammer, a storage container holder is provided on the superstructure of the vibration rammer, which is provided for receiving and supporting the at least one storage container on the vibration rammer. Their essential purpose is the secure attachment and mounting of the reservoir to the superstructure of Vibrampstampfers. In order to ensure in particular a uniform and reliable working operation, it is now preferred according to the invention that the reservoir holder is vibration-dampened in relation to the vibrations which originate in particular from the machine frame. In other words, starting from the machine frame to the storage container holder, there is thus at least one damping stage which eliminates or at least dampens the vibrations emanating from the machine frame to the storage container holder and thus also to at least one storage container arranged thereon. This ensures that the at least partially filled with liquefied gas at least one reservoir is not subject to the full emanating from the machine frame vibration intensity and thus takes place only a significantly reduced vibration transmission from the machine frame to the at least one reservoir during operation.

Basically comes to the arrangement of the vibration-damped reservoir holder on the superstructure of the vibratory rammer also a variety of possible positions into consideration. However, according to the invention, the storage container holder is arranged on the guide bracket, in particular either directly or exclusively via a damping device. The guide bracket is presently expressly a part of the superstructure of the vibratory rammer. This arrangement has the advantage that the usually already existing for the guide bracket vibration damping can be used simultaneously for vibration damping of the reservoir holder. The vibration damping of the reservoir holder is thus provided in other words on the vibration damping of the guide bracket relative to the machine frame. However, starting from this embodiment, the vibration damping of the reservoir holder can be further increased if a further, additional vibration damping is present between the reservoir holder and the guide bracket. The reservoir holder is thus stored in this embodiment via suitable vibration damping elements on the guide bracket. Between the machine frame and the reservoir holder in this embodiment thus two successive damping stages are present, on the one hand between the machine frame and the guide bracket of the superstructure and on the other hand between the guide bracket and the reservoir holder. Overall, a particularly efficient vibration damping of the reservoir arranged in the reservoir is thus obtained.

In vibration tampers often find use guide that allow a guide of the vibratory tamper both from the back and from the front relative to the direction of the vibrating tampers. Especially for these guide brackets, it has proved to be advantageous if the reservoir holder is arranged on the guide bracket in the main working direction between the guide bracket storage on the machine frame and the rear handle portion of the guide bracket. The guide bracket storage is the part of the guide bracket to which it is articulated on the machine frame, in particular via one or more vibration damping elements. In other words, the storage container holder is arranged offset to the rear on the guide bracket in relation to the main working direction. The rear handle portion of the guide bracket is the area that is encompassed by a located behind the vibration tamping machine operator. The main working direction is the direction in which the vibratory ramming device is predominantly moved during operation. In the case of vibration tampers with a tamping axis running obliquely to the ground, this is, for example, the direction in which the tamping axis is tilted relative to the ground. This arrangement of the reservoir holder is advantageous in that the reservoir holder and the at least one reservoir then act as a counterbalance to the slope of the soil compaction machine.

It is also provided that the reservoir holder is arranged between two side rails of the guide bracket. The guide bracket usually has at least partially a U-shape, which can be more or less additionally three-dimensionally deformed. In the end region of the two U-legs, it is hinged vibration-damped on the machine frame. In particular, the connecting part between the two side legs or spars of the guide bracket is often used as a grip area for the machine operator, so that attachment of the reservoir holder at this point is disadvantageous. Due to the arrangement of the reservoir holder between the two side rails can also be easily avoided that the weight distribution on the soil compaction machine is too one-sided and thereby, for example, the stability of the Bodenverdichtungsmaschine is adversely affected. The simultaneous arrangement of the reservoir holder on both side rails also provides a particularly stable support and is preferred.

As already mentioned above, however, it is advantageous for the at least one storage container to be arranged exchangeably on the superstructure and in or on the storage container holder. This means that the at least one storage container is thus dismantled and removed for filling by the vibratory rammer. "Interchangeable" is therefore in the context of the invention in particular also to be understood as that a quick and routine installation and removal of at least one reservoir from the reservoir holder is provided. This possibility has the advantage that it is possible to fill reservoirs independently of the vibratory rammer and in this way, for example during the filling process of at least one empty reservoir, it is possible to operate the vibratory rammer in parallel with at least one filled reservoir. Ideally, the exchange should be as uncomplicated as possible and in a short time, for example a few minutes.

Also, a connection device for connecting the at least one storage container is therefore provided on a vibration tamper according to the invention, which comprises at least one quick-release system. In principle, the connection of the at least one storage container can generally be made use of the connection possibilities of liquefied gas containers to line systems which are known in the prior art. However, the quick coupling system is characterized by the fact that it enables a reliable connection and separation between the at least one reservoir and the pipe system in a relatively simple and yet reliable manner. It is envisaged that the quick release system is a tool-free operable quick release system. A quick coupling system can be operated without tools if the connection and disconnection of the coupling device between the reservoir and the pipe system can be made purely manually and without the further use of tools. This is advantageous in that then need not be available special tools for connecting and / or releasing the at least one reservoir of the connection device. A suitable quick coupling system is characterized in that it ensures that, for example, when connecting the reservoir to the connecting device, first a coupling connection is established and only then takes place a valve opening for the transfer of liquefied gas from the reservoir into the line system. The quick coupling system can thus be designed, for example, as a rotary closure, in particular a bayonet closure, which first ensures locking and then a valve opening and, in the event of removal of the reservoir, first a valve closure and only then a coupling separation.

The storage container holder has a holding device, which is designed for releasably fixing the at least one storage container in the storage container holder. The holding device is thus distinguished by the fact that it fixes the at least one reservoir detachably in the reservoir holder, so that this retains a defined position in the reservoir holder, for example, during operation. Such a holding device may for example be a quick-release belt, a snap closure, a holding plate or the like. The holding device may in particular also be part of a protective cover, as will be explained below. The holding device is further preferably designed in such a way that it fixes the at least one storage container positively and / or non-positively in or on the storage container holder.

In principle, different storage containers can be used, with storage containers having a maximum volume for liquefied gas in the range from 200 ml to 20,000 ml, in particular in the range from 400 ml to 1000 ml, having proven to be particularly preferred. The latter are often refillable, for example, in accordance with legal requirements by the machine operator himself, so that it is possible to dispense with the performance of special filling service providers. Further common sizes for liquefied gas containers are also gas cylinders with filling masses of 5 kg and 11 kg, which in principle can also be used.

According to the invention it is provided that the at least one storage container is a cartridge, in particular a Schraubventilkartusche or a bayonet valve cartridge. In the present case, a cartridge is understood to mean a small gas cylinder with a filling volume which does not exceed 1,000 ml. The use of cartridges is advantageous in that they are relatively light and small, and thus represent an optimal compromise between the possible filling interval with an operating interval, in particular when using multiple cartridges on the vibratory tamper, and weight. Screw valve cartridges or bayonet valve cartridges are characterized in that they have a screw valve connection or a bayonet valve connection and thus can be connected directly via a suitable connection device to the line system of the vibration tamper.

Taking into account the storage container sizes currently available for liquefied gas, it is further provided that the storage container holder is designed to accommodate at least two storage containers. This allows the use of smaller reservoir while extending the maximum possible operating interval with a total liquid gas filling of the vibratory rammer. An operating interval indicates the time span over which the vibrating rammer can be operated with an overall filling, ie when using a plurality of storage containers based on the filling of all storage containers, without refilling, with average total liquid consumption. In principle, the use of smaller storage containers is advantageous in that, depending on the national legal requirements, they can often be filled by a so-called qualified person on site via suitable mobile filling stations, so that the operator of such a vibratory rammer, for example, only a small number of suitable storage containers must be available on site.

If a plurality of storage containers are used, the storage containers are optimally connected in parallel to each other, so that the simultaneous removal of liquefied gas from all existing storage containers is possible. The line system of the vibration rammer therefore has, according to the invention, a connection device for the parallel connection of the at least two storage containers to the line system. For this purpose, the connection device can be designed, for example, in the form of a T-piece for at least two storage containers or be a type of connection bar with a gas discharge line and a plurality of gas supply lines or a plurality of connection points for a respective storage container. According to the invention, the connection device further comprises, for the connection side of the at least two reservoirs, at least one suitable safety device which is designed such that it effects a closure of the connection device, provided that no reservoir is connected to the respective connection for a reservoir. This feature is important in that when connecting and removing at least one reservoir, a separation of this reservoir from the connection device is required and in this case any leakage of any remaining liquid gas from another connected to the terminal reservoir is absolutely necessary. For this purpose, for example, before each connection point of a reservoir to the connection device suitable check valves or the like may be provided, which automatically and automatically effect a closure of the connection point to the outside when removing a reservoir.

The essential task of the reservoir holder is to enable a secure and reliable attachment to the at least one reservoir on the vibratory rammer. For example, the storage container holder may have a suspension or similar storage means for receiving the at least one storage container. Ideally, however, the reservoir holder is designed as a receptacle with a bottom and at least two laterally vertically upstanding side walls, in which the at least one reservoir is adjustable to the ground. The connection of the receiving tray to the guide bar, in particular to its opposite side legs, is ideally effected via the side walls. In this way, an easy to manufacture and at the same time extremely stable reservoir holder is obtained.

According to the invention, the storage container holder comprises a side guard, which at least partially shields the at least one storage container in the storage container holder to the outside. The term "side" relates in particular to the outer edge regions of the reservoir holder located in the horizontal plane. The side protection can consist, for example, of one or more wall elements that at least partially delimit Ensure the reservoir holder to the outside. The side protection does not have to be formed over the entire surface, but may, for example, also have interruptions or be in the form of a grid in the form of a grid. It is important that the side protection allows at least a rough shielding of the at least one reservoir to the outside, for example, to prevent or at least complicate the intrusion from the outside into the interior of the reservoir holder. Ideally, the side protection is at least insofar designed that it allows in particular a protection of the at least one reservoir at the level of the connection device, for example, to prevent inadvertent release of the valve connection between the conduit system and the at least one reservoir when the vibration tampers fall over.

There may also be a protective cover, which is designed for at least partial covering of at least one storage container arranged in the reservoir. The protective cover in particular allows a cover of the at least one storage container upwards or a protection in the vertical direction to at least one storage container from above. The protective cover is therefore also preferably used in combination with the side protection. The protective cover accordingly prevents the at least one reservoir from being inadvertently damaged from above. The protective cover may also have recesses and / or a lattice-like design, with a full-surface design of the protective cover having proven to be preferred here.

To allow, for example, to replace the at least one reservoir, access into the interior of the reservoir holder, the protective cover is ideally designed to be movable and stored in particular pivotally mounted on the guide bracket. To replace the at least one reservoir, the protective cover can thus be removed, for example, swung up, and mounted again after the replacement, for example, swung down, are. In order to enable a reliable covering of the at least one storage container by the protective cover, this preferably has a closure mechanism, in particular a suitable screw cap, for locking the protective cover in a closed position. The screw is in particular captive on the protective cover arranged to prevent, for example, a loss of the screw cap when changing the at least one reservoir.

Ideally, the protective cover is designed in the form of a pivot hood, which in particular comprises a substantially flat and completely closed hood element.

As already mentioned above, a holding device is preferably arranged in the storage container holder, via which the positioning of the at least one storage container in the storage container holder is ensured. It is now preferred to form this holding device at least partially as part of the protective cover, so that the protective cover additionally performs a holding function in addition to the pure protective function. In principle, the holding device arranged on the protective cover can be varied in many ways. It is optimal, for example, if the holding device has an elastic pressing element which is designed in such a way that it exerts a contact pressure acting in the closing direction of the protective cover on the at least one storage container in the storage container holder. When the protective cover is closed, in other words, the elastic pressing element preferably comes into contact directly or indirectly with the at least one storage container and is at least partially compressed by the further closing of the protective cover. The resulting contact pressure on the at least one storage container is now preferably used to achieve a position stabilization of the at least one storage container in the storage container holder. Concretely, the holding device can for example comprise a holding and protective sleeve, which in the holding state, i. when the protective cover is closed, at least partially reaches its end-side edge region for abutment with at least one storage container. The holding and protective sleeve is thus preferably pressed onto the at least one storage container from above, optimally at least partially surrounding connecting elements of the at least one storage container with the line system of the vibrating tamper, whereby mechanical protection, in particular of this sensitive area, is achieved. Alternatively, the sleeve can also be provided as a pure protective sleeve and used.

As already mentioned above, the at least one storage container is used for receiving and storing liquid gas in the liquid state. However, the drive motor burns the liquefied gas in the gaseous state. In order to enable a gas supply to the drive motor under constant pressure conditions, the line system preferably comprises between the at least one reservoir and the internal combustion engine thus a pressure regulator, in particular one self-regulating pressure regulator. The essential task of the pressure regulator is thus to regulate the pressure of the gaseous liquefied gas fed to the drive motor to a constant level, in order to ensure a constant gas pressure and thus to enable trouble-free operation.

In the line system, an evaporator is preferably present between the at least one storage container and the drive motor, in order to ensure complete evaporation of the liquefied gas. The physical properties of liquefied petroleum gas, especially at low outside temperatures, can lead to liquefied petroleum gas reaching the drive motor at least partially also in liquid form during operation. To prevent this, according to the invention between the at least one reservoir and the drive motor of the evaporator interposed, the essential task is the conversion of liquid liquefied gas into gaseous liquefied gas. Such evaporators are also known in the prior art. It is further preferred if the evaporator in the line system is arranged as close as possible to the at least one storage container in order to keep the liquid fraction of liquid gas in the entire line system as low as possible.

In order to further optimize the operation of the evaporator, this may preferably further comprise a heat supply, via which the evaporator thermal energy for the evaporation of liquid LPG is supplied. It is optimal for this purpose, for example, when the heat is supplied to heat via warmed by the drive motor cooling air, which can be achieved for example by a suitable cooling air flow. Additionally or alternatively, it is also preferable to supply heat to the heat via an oil circuit fed with engine oil. This motor oil supplied to the drive motor in a lubrication circuit likewise heats up during operation, so that a diversion of the oil to the evaporator can be used in addition to engine oil cooling. Both variants have the advantage that, as part of the combustion process of gaseous liquefied gas in the drive motor, they supply heat energy to the evaporator and thus enable a more efficient use of energy.

Optimal operation is correspondingly possible if both an evaporator and a pressure regulator are provided in the line system, wherein the evaporator is arranged at the line system to the engine in front of the pressure regulator. It is now optimal if the evaporator and the pressure regulator are combined in a common machine element, whereby a particularly efficient construction of the entire system succeeds. A combined component is then when it combines the two functional sub-units "evaporator" and "pressure regulator" in a common unit or in a common module.

With regard to a reliable and controlled working operation, the evaporator and / or the pressure regulator thus assumes a central importance. It is therefore preferable to store the evaporator and / or the pressure regulator via a holder on the vibratory ramming device, wherein the holder is vibration-damped relative to the machine frame outgoing vibrations. As a result, in particular the vibration load of the evaporator and / or pressure regulator is reduced during operation and thus increases the reliability of the function.

In principle, the holder of the evaporator and / or pressure regulator can be arranged at almost any point of the Vibratorstampfers, and it is also preferred to arrange the holder of the evaporator and / or pressure regulator, in particular directly, on the superstructure and especially on the guide bracket of the Vibrationsstampfer , in particular via at least one vibration damper. In this arrangement, therefore, the evaporator and / or the pressure regulator, the already frequently existing vibration damping of the guide bracket in itself benefits, preferably supplemented by a further attenuation stage between the guide bracket and the holder of the evaporator and / or pressure regulator.

The holder for the evaporator and / or pressure regulator can be an independent component or else part of the reservoir holder. In the latter case, the holder is in other words thus an integral part of the reservoir holder, which also serves to accommodate the at least one reservoir simultaneously for holding the evaporator and / or the pressure regulator.

The vibration tamper preferably comprises an external oil cooler for reducing the engine oil temperature during operation. Thus, the possibly higher compared to gasoline or diesel propulsion engines higher operating temperatures in the combustion of liquefied gas can be taken into account.

For safety reasons, it is preferred if the vibration tamper has a tilt cut-off, in particular comprising a tilt sensor and / or an oil pressure sensor. The essential feature of the inclination shutdown is that it forcibly shuts off the working operation of the drive motor when exceeding a predetermined maximum inclination of the vibratory rammer, starting from a normal position. This ensures, for example, that the vibration tamper in case of improper positioning of the machine, for example in the lying State, is not put into operation, or discontinued operation of the machine does not continue. For this purpose, the inclination circuit can have, for example, a suitable control unit which evaluates the measured values ascertained by the inclination sensor and / or oil pressure sensor and then intervenes accordingly in the engine control and / or valve control if an over-inclination is detected. An inclination sensor may, for example, be a position sensor. The oil pressure sensor detects the oil pressure in the oil line system of the drive motor. Exceeds the vibration tampers a certain inclination, for example by falling over, the oil pressure conditions change at suitable locations in the oil line system drastically, so that indirectly the inclination of the vibration tamper can be monitored.

A further preferred development of safety-relevant aspects is to integrate an automatic shutdown in the vibratory tamping, which is designed in such a way that they only with sufficient negative pressure in a suction line of the engine LPG in or through the evaporator or the above-mentioned machine element with Let evaporator and pressure regulator flow. The automatic shutdown thus represents a kind of feedback, which ensures that liquefied petroleum gas in the evaporator is only forwarded when the drive motor is in operation and there is a corresponding negative pressure in the intake line of the drive motor. On the other hand, if the drive motor is switched off, there is no longer any negative pressure in the intake line. The automatic shutdown now ensures that in this case no further liquid gas flows into or through the evaporator or at least the common machine element with an evaporator and a pressure regulator according to the foregoing, so that the formation of unburned amounts of gaseous liquefied gas is minimized as far as possible. For example, the automatic switch-off can also be electronically controlled and for this purpose comprise a control unit, a pressure sensor and a control valve controlled by the control unit as a function of the pressure values in the intake line determined by the pressure sensor, in particular close to the evaporator. Alternatively, a mechanical solution is conceivable in which a vacuum line with membrane a pressure connection between the intake manifold and a machine connected to the fuel supply of the drive motor machine part, in particular the evaporator, allows, for example, a valve may be provided at the evaporator inlet through pulled in the vacuum line negative pressure is pulled against a restoring force in its open position. Specifically, the automatic shutdown, for example, control a shut-off valve and trigger this example, an interruption of the fuel flow to the evaporator out when there is no sufficient negative pressure in the intake manifold to the drive motor. Evolves a sufficient negative pressure in the intake, for example, during commissioning of the drive motor, on the other hand, the automatic switch-off releases the fuel flow to the evaporator via the pressure regulator. The automatic shut-off thus controls whether the pressure regulator allows liquid gas to flow to the evaporator or not.

It is also possible to arrange the conduit system at least partially within the guide bracket. In particular, formed as a conduit hose sections can be introduced into the often bent from pipes and / or welded guide bracket or partially threaded through sections of the guide bracket, which in addition to a particularly efficient space utilization further mechanical protection of these line sections is obtained to the outside.

Liquefied gas is heavier than air in the gaseous state and thus tends to accumulate in the bottom area in the event of uncontrolled outflow. This is particularly relevant, for example, when the vibration tamper according to the invention is used in trenches, in a construction pit or similar operating environments. In a further preferred embodiment, the vibration tamper therefore comprises a gas sensor, which is designed to determine the gaseous liquefied gas concentration in the external environment of the vibration tampers. Furthermore, there is an emergency shutdown, for example with a suitable control unit connected to the gas sensor, which switches off the drive motor when the gas sensor detects the exceeding of a predetermined concentration value in the external environment of the vibration tamper.

Fig. 1

Seitenansicht auf einen gattungsgemäßen Vibrationsstampfer;

Fig. 2a

perspektivische Schrägansicht von schräg rechts vorn auf einen Vibrationsstampfer mit Flüssiggasantrieb;

Fig. 2b

Rückansicht auf den Vibrationsstampfer aus Fig. 2a;

Fig. 3

perspektivische Detailansicht des Führungsbügels aus den Figuren 2a und 2b von schräg hinten rechts;

Fig. 4

Detailansicht der Anschlusseinrichtung aus Fig. 3;

Fig. 5

Prinzipschaltbild einer Anschlusseinrichtung mit mehreren, parallel geschalteten Vorratsbehältern;

Fig. 6

Prinzipschaltbild einer mit Motoröl gespeisten Wärmezufuhr zum Verdampfer;

Fig. 7

Prinzipschaltbild einer Unterdruckabschaltung; und

Fig. 8

Prinzipskizze eine Neigungsabschaltung.

The invention will be further explained with reference to the exemplary embodiments illustrated in the figures. They show schematically:

Fig. 1

Side view of a generic vibration tampers;

Fig. 2a

perspective oblique view from obliquely right front on a vibratory rammer with LPG drive;

Fig. 2b

Rear view on the vibration tamper off Fig. 2a ;

Fig. 3

perspective detail view of the guide bracket from the FIGS. 2a and 2b from diagonally back right;

Fig. 4

Detail view of the connection device off Fig. 3 ;

Fig. 5

Block diagram of a connection device with a plurality of parallel connected storage containers;

Fig. 6

Schematic diagram of a supplied with engine oil heat to the evaporator;

Fig. 7

Block diagram of a vacuum shut-off; and

Fig. 8

Schematic diagram of an inclination switch-off.

Identical components are indicated in the figures with the same reference numerals. Repetitive components are not necessarily marked individually in each figure.

Fig. 1a shows a vibration tamper 1, comprising a superstructure 2a, wherein the superstructure 2a has a drive motor 3 and a guide bracket 4. Furthermore, a substructure 2b with a padfoot 5 with a bottom plate 9 and a transport handle 8 is present. The substructure 2b is connected via a bellows 6 to the superstructure 2a. The guide bracket 4 and the drive motor 3 of the superstructure 2 a are indirectly connected to one another via a machine frame 10 or a connection bracket 10. Within the bellows 6, a power transmission device, such as a connecting rod, arranged, which converts the rotational driving force of the drive motor 3 in a linear motion and transmits to the padfoot 5. Between the drive motor 3 and the padfoot 5 is thus a total unspecified and known per se drive gear 11 is present, via which the drive energy of the drive motor 3 is transmitted to the padfoot 5. In operation, the padfoot 5 stamps approximately in the vertical direction along the stamp axis S, for example at a frequency of about 10 Hz, over the ground subsurface U and thereby compresses the substrate material. The leadership of the vibratory rammer 1 is done manually via the guide bracket 4, which is mounted on elastic damping bearings 7 on the machine frame of the superstructure 2a. The main working direction a is that direction of movement of the vibratory rammer in the working mode, in which the ramming axis S is inclined towards the front relative to the horizontal plane of the ground and into which it automatically moves in working mode.

The vibration tamper 1 is assigned to the so-called "walk-behind machines", whose superordinate common feature lies in the fact that the machine operator carries the soil compaction machine behind the machine during working operation. Correspondingly, the main working direction a is also the direction of movement, which is opposite to the region of the guide bracket 4 projecting from the machine.

An essential aspect of the invention lies in the fact that the drive motor 3 is a liquid-gas-driven drive motor 3. This will be in the rest FIGS. 2a to 8 further illustrated by the vibration rammer 1

The FIGS. 2a to 4 illustrate further with the integration of the liquid-gas-powered drive motor 3 in the vibratory tamper 1 related aspects. In addition to the liquid-gas-powered drive motor 3 itself, essential elements on the superstructure 2 a of the vibration rammer 1, in particular of the liquefied gas supply system, a reservoir holder 14, storage tank for liquefied gas 15, an evaporator pressure regulator device 16, a line system 17, a connection device 18 and a protective cover 19.

The liquid gas required for the operation of the drive motor 3 is stored in the vibratory rammer 1 in the storage containers 15 on the vibratory rammer 1 on the superstructure 2 a itself. Specifically, this is the embodiment according to the FIGS. 2a to 4 by two 0.425 kg gas cylinders, which are arranged interchangeably in the reservoir holder 14 and stand on the bottom plate 26 directly. Such as from the FIG. 3 is more apparent, the two gas cylinders 15 are each connected via a quick coupling 20 to the connection device 18, which includes a collecting block 22 next to the connection ends 21 to the quick coupling 20, which is connected on the output side with the line system 17 to the drive motor 3 out. The two reservoirs 15 are thus arranged parallel to each other, so that LPG from the reservoirs 15 at the same time via the connection device 18 to the line system 17 can be removed. The conduit system 17 is thus functionally a gas supply line via which the drive motor 3 is ultimately supplied with the liquefied gas. The line system 17 may include hose and / or pipe sections, valve connections, etc.

Coming from the storage containers 15, the liquefied gas is initially present in a substantially liquid state. However, the drive motor 3 burns the liquefied gas in the gaseous state. Between the drive motor 3 and the reservoirs 15, therefore, the evaporator pressure regulator unit 16 is arranged in the line system 17, the liquid liquid from the storage tanks 15 is supplied on the input side and supplies the output side gaseous liquefied gas for forwarding to the drive motor 3. In the present embodiment, the evaporator pressure regulator unit 16 is also a coherent component or a multifunctional module, in which an evaporator 23 and a pressure regulator 24 are arranged, as for example in FIG FIG. 6 is specified in more detail.

The FIGS. 2a to 3 illustrate, among other things, the existing vibration-damped storage of the storage container storage 14 on the superstructure 2a relative to the machine frame 10 of the superstructure 2a. The arrangement of the reservoir holder 14 on the guide bracket 4 is a vibration damping of the machine frame 10 relative to the reservoir holder 14th already by the damping bearing 7 between the guide bracket 4 and the machine frame 10. In the present embodiment, in addition, between the guide bracket 4 and the reservoir holder 14, a further damping stage with the damping elements 25 is present. The storage container 14 is thus supported on the damping bracket 25 on the guide bracket 4, whereby a direct and immediate storage of the storage container 14 on the guide bracket 4 is possible and is encompassed by the invention. The storage container holder 14 essentially comprises a trough-like base body with a bottom plate 26 and two in the lateral edge region of the bottom plate 26 towering in the vertical direction side walls 27. About the side walls 27, the tub-like reservoir holder 14 via the damping elements 25 on fixedly connected to the guide bracket 4 retaining tabs 28th hinged. These retaining tabs 28 are connected to the side rails 29 of the guide bracket 4. The reservoir holder 14 is in other words at two opposite end portions of the guide bracket 4 vibration-mounted, so that vibrations including the guide bracket 4 are transmitted attenuated to the reservoir holder 14. Especially FIG. 3 illustrates that the reservoir holder 14 is further spaced as far as possible to the damping bearings 7 in the direction of the handle portion 30 between the side rails 29 of the guide bracket. Thereby, the reservoir holder 14 can be used as a kind of vibration counterweight for further reduction of guide bow vibrations.

At the reservoir holder 14, a side guard 31 is also present, which complements the protective effect of solid and full-surface side walls 27 to the back of the vibratory rammer 1 and to the machine operator out. The side guard 31 is concretely a transverse strut which extends in the rear region of the storage container holder 14 between the side walls 27.

Further protection of the storage container 15 arranged in the storage container holder 14 is further obtained by the protective cover 19. The protective cover 19 is concretely a protective cover which is pivotably arranged on a cross member 32 of the guide bracket and which, in working operation, is in accordance with the FIGS. 2a and 2b is swung down to the reservoirs 15 and, for example, to replace the reservoir 15, according to the FIG. 3 can be swung upwards. In the swiveled-up state, the protective cover 19 thus releases the storage containers 15, so that these can be easily and simply removed or replaced from the storage container holder 14. In the lowered state prevents the protective cover 19 damage to the reservoir 15 as the covered by the protective cover 19 areas of the connecting device 18 and the conduit system 17 from above. The protective cover 19 further comprises a locking screw 37, by the rotation of the protective cover 19 in the closed position in accordance with FIGS. 2a and 2b can be determined. The closure screw 37 engages in a corresponding counterpart 38 to the reservoir holder 14. This prevents the protective cover 19 from jumping open in uncontrolled operation.

In addition to the substantially full-surface protective hood, the protective cover 19 further comprises two protective sleeves 33, which are arranged on the inside of the protective cover 19 and project in the direction of the reservoir 15. The protective sleeves. 33 are formed in such a way that they cover the valve connection areas of the connection device 18 to the reservoir 15 at least partially in the lowered state of the protective cover 19 and surrounded to the sides, so that thereby an additional protection of this safety-sensitive area is obtained. In addition, a slot recess is provided in the protective sleeves, through which connection elements for connecting the storage container 15 to the connection device 18 are guided.

Another essential feature of Vibrationsstampfers 1 is the arrangement of the evaporator pressure regulator unit 16 on the guide bracket 4 in also with respect to the machine frame 10 and against the guide bracket vibration damped way. Between the evaporator pressure regulator unit 16 (or the relevant holding device 36, which is the holder of the evaporator pressure regulator module 16) and the retaining tab 34 on the guide bracket 4 is thus also a damping element 35 is present, so that guide bow vibrations in a muted manner the evaporator pressure regulator unit 16 are transmitted.

FIG. 4 illustrates the basic operation of the quick couplings 20. These include the terminals 21 which are arranged at the hose ends of the connecting device 18. At the storage containers 15 corresponding coupling counterparts 39 are provided, which are designed to produce a gas-tight transfer connection between the reservoir 15 and the conduit system 17 for receiving the terminals 21. Specifically, the quick coupling 20 to the property that a valve opening is possible only when produced gas-tight fluid connection and a separation of the quick coupling 20 is possible only after closing the corresponding valves. The quick couplings 20 are purely manually by thrust and rotational movements of the terminals 21 against the coupling counterparts 39 can be coupled or uncoupled, so that, for example, no special tool is required to replace the reservoir 15.

FIG. 5 is a block diagram and illustrates in an alternative embodiment to the FIGS. 2a to 4 the parallel arrangement of more than two storage containers 15 in the reservoir holder 14. In the storage containers 15 of FIG. 5 These are, for example, cartridges with a maximum filling volume of 1000 ml. The cartridges 15 are connected to the connecting device 18 via quick couplings 20 already described above. For each line connection between a cartridge 15 and the connection device 18, a stopcock 40 and a downstream check valve 41 are also provided in each case. The check valve 41 has essentially the task of providing an automatic termination of the connecting device 18 to the outside, when a reservoir 15, for example when replacing, is separated from the terminating device 18. The non-return valve 41 thus automatically ensures that the liquid gas present in the other storage containers does not flow out via the one connecting arm on which the storage container 15 has been removed. Between the connection device 18 and the further line system 17 to the drive motor 3 through a central stopcock 42 is also provided, via which the liquid gas forwarding of the reservoirs 15 to the drive motor 3 thus can be locked or released centrally. It goes without saying that in FIG. 5 specified connection scheme can be extended or reduced almost arbitrarily to different numbers of storage containers 15.

For a proper operation of the liquid-gas-driven drive motor 3, it is important that this liquid gas is supplied in the gaseous state. In order to allow the most quantitative possible evaporation of the liquefied gas, the evaporator-pressure regulator unit 16 with the evaporator 23 and the pressure regulator 24 is arranged between the connection device 18 and the drive motor 3 in the line system 17. The pressure regulator 24 is connected downstream of the evaporator 23 in the fluid outflow direction to the drive motor 3. The essential task of the pressure regulator 24 is to ensure a constant supply gas pressure to the drive motor 3 out. The pressure regulator 24 is an automatically acting pressure regulator, which automatically performs a corresponding pressure control. On the other hand, the evaporator 23 is intended to ensure complete evaporation of the liquid gas flowing out of the storage containers 15. In the present embodiment, a heat supply to the evaporator 23 is provided in such a way that the engine 23 heated engine oil is supplied to the evaporator. This is in the embodiment according to Fig. 6 a driven by the drive motor 3 oil pump 43 is provided, the warmed engine oil from the engine oil sump 44 to the evaporator 23 promotes and after the evaporator 23 back to the engine oil sump 44. In this evaporator oil circuit 45, a pressure relief valve 46 is further arranged.

In FIG. 7 is the basic operation of a shutdown for the vibratory tamper 1 exemplified. The automatic shutdown causes the gas supply to the drive motor 3 is then interrupted when the drive motor 3 does not request fuel, or when the drive motor 3 is turned off. From the basic principle, the in FIG. 7 specified automatic shutdown to the fact that only a sufficient negative pressure prevails in the intake manifold 46 between the carburetor 47 and the drive motor 3, if by the rotational movement of the drive motor 3, and resulting movement of the piston in the intake manifold 46 of the drive motor 3, a negative pressure arises. For this reason, it is thus provided that there is a feedback between the negative pressure in the suction line 46 to the evaporator pressure regulator unit 16, which only allows a liquid gas forwarding through the evaporator pressure regulator unit 16 when a sufficient negative pressure in the suction line 46 prevails. For this purpose, a pressure signal line 48 between the suction line 46 and the evaporator pressure regulator unit 16 is provided, through which a suitable shut-off device in the evaporator pressure regulator unit 16 is controlled in such a way that a leakage of liquefied gas from the evaporator pressure regulator unit 16 to the drive motor 3 only with sufficient negative pressure in the suction line 46 is possible.

FIG. 8 Finally, the principle of operation of an inclination shutdown illustrates. An essential element of the inclination switch-off is initially a sensor 49, with which at least the exceeding of a certain maximum inclination value of the vibratory rammer 1 relative to the ground horizontal surface of the ground U can be determined. In this case, the inclination describes the tilt angle of the stamp axis S of the vibratory rammer 1 with respect to a vertical perpendicular to the horizontal horizontal plane. The measurement data determined by the sensor 49 are transmitted to a control unit 50. If the control unit 50 determines that an inclination limit value has been exceeded, it triggers an engine stop. This can be done for example by interrupting the Zündstromversorgung 51 or by similar measures. In addition or as an alternative, blocking valves or similar measures can also be triggered by the control unit 50 in this case, for example, in order to prevent an uncontrolled outflow of liquefied gas from the fallen-over vibration tamper 1.

Claims (12)

1. A vibration tamper (1) for ground compaction, comprising

   - an upper structure (2a) comprising a guide bar (4) and a drive engine (3) mounted on a machine frame (10),

   - a lower structure (2b) comprising a tamper base (5) with a tamper plate (9), the tamper base (5) being driven by the drive engine (3), and

   - a power train (11), via which a power connection is established between the drive engine and the tamper base (5) such that the tamper base (5) can be moved in relation to the upper structure (2a) along a tamping axis (S) with at least one compaction amplitude,

   characterized in that

   - the drive engine (3) is powered by liquid gas,

   - the upper structure (2a) comprises at least one storage container (15) for liquid gas,

   - a gas supply line (17), via which vaporized liquid gas can be supplied to the drive engine (3), is provided,

   - the storage container (15) is arranged in a replaceable manner in a storage container bracket (14), the storage container bracket (14) comprising a holding device for the releasable fixation of the at least one storage container (15) in the storage container bracket (14),

   - the storage container bracket (14) is arranged on the guide bar (4) between two lateral bars (29) of the guide bar (4),

   - a connection means (18) for the connection of the at least one storage container (15) to the gas supply line (17) is provided, wherein the connection means (18) is a quick coupling system (20) that does not require the use of tools,

   - the storage container bracket (14) is configured to receive at least two storage containers (15), wherein the connection means (18) is configured for the parallel connection of the at least two storage containers (15) to the gas supply system (17),

   - the connection means (18) further comprises on the connection side of the at least two storage containers (15) at least one suitable safety device configured in such a way that it effects the closure of the connection means (18) when there is no storage container (15) connected to the respective connections for the storage containers (15),

   - The storage container bracket (14) comprises a lateral guard (31), which at least partially shields the at least one storage container (15) laterally to the outside,

   - The storage container (15) is a cartridge and has a filling capacity for liquid gas that does not exceed 1000 ml.
2. The vibration tamper (1) for ground compaction according to claim 1,
   characterized in that
   the storage container bracket (14) comprises at least one of the following features:

   a) it (14) is vibration-dampened in relation to vibrations emitted by the machine frame (10);

   b) it (14) is arranged on the guide bar (4) in a vibration-dampened manner; and

   c) it (14) is arranged on the guide bar (4) between the guide bar mount (7) on the machine frame (10) and the rear gripping region (30) of said guide bar (4) in the main working direction.
3. The vibration tamper (1) for ground compaction according to the preceding claims,
   characterized in that
   the at least one storage container (15) comprises at least one of the following features:

   a) it (15) has a maximum filling capacity for liquid gas in a range from 400 ml to 1000 ml;

   b) it (15) is a screw-valve cartridge or a bayonet-type valve cartridge.
4. The vibration tamper (1) for ground compaction according to one of the previous claims,
   characterized in that
   a protective cover (19) is provided, which is configured to cover at least one storage container at least partially, in particular a storage container (15) arranged in the storage container bracket (14).
5. The vibration tamper (1) for ground compaction according to claim 4,
   characterized in that
   the protective cover (19) comprises at least one the following features:

   a) it (19) is mounted in a pivotable fashion on the guide bar (4), in particular on an upper cross strut of the guide bar;

   b) it (19) has a closing means (37, 38) for locking the protective cover (19) in a closed position;

   c) it (19) has a holding device (33) for the fixation of a storage container in the storage container bracket (14), the holding device comprising in particular

   - an elastic pressure element configured to exert an effective contact pressure on the at least one storage container (15) in the storage container bracket (14) in the closing direction of the protective cover (19), and/or

   - a retaining and protective sleeve (33), which, when in its holding state, comes to rest at least partially with its front edge region against at least one storage container (15).
6. The vibration tamper (1) for ground compaction according to one of the previous claims,
   characterized in that
   a vaporizer (23) is provided in the supply system (17) between a gas supply or the at least one storage container (15) and the drive engine (3) in order to ensure a complete vaporization of the liquid gas.
7. The vibration tamper (1) for ground compaction according to claim 6,
   characterized in that
   the vaporizer (23) has a heat supply that is supplied with heat at least by way of cooling air warmed by the drive engine (3) or by way of an oil circuit (45) containing motor oil.
8. The vibration tamper (1) for ground compaction according to claim 5 or 6, characterized in that
   the vaporizer (23) is mounted by means of a bracket (36) on the vibration tamper (1), wherein said bracket (36) is vibration-dampened vis-à-vis vibrations emitted by the machine frame (10).
9. The vibration tamper (1) for ground compaction according to claim 8,
   characterized in that
   the bracket (36) comprises at least one of the following features:

   a) it (36) is arranged on the guide bar (4) of the vibration tamper (1) by means of at least one vibration damper (35);

   b) it (36) is part of the storage container bracket (14) according to one of claims 1 to 3.
10. The vibration tamper (1) for ground compaction according to one of the previous claims,
    characterized in that
    it comprises at least one the following features:

    a) an external oil cooler is provided for the reduction of the motor oil temperature of the drive engine (3) in operation;

    b) an inclination shutdown system is provided, in particular comprising an inclination sensor and/or an oil pressure sensor;

    c) the supply system (17) is arranged at least partially within the guide bar (4).
11. The vibration tamper (1) for ground compaction according to one of the previous claims,
    characterized by
    the provision of an automatic shutdown system that is configured so that it only allows liquid gas to flow through a vaporizer (23) when there is adequate negative pressure in the suction pipe (46) of the drive engine (3), wherein the automatic shutdown system in a pressure regulator (24) triggers a blocking and release of the flow of fuel.
12. The vibration tamper (1) according to one of the previous claims,
    characterized by
    the provision of a gas sensor (49) that is configured to determine the liquid gas concentration in the surrounding environment of the vibration tamper (1), and the provision of an emergency shutdown system that switches the drive engine (3) off when the gas sensor (49) detects a concentration level in excess of a determined concentration level in the surrounding environment of the vibration tamper (1).

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