Abstract:
A hand-guided soil compacting machine, such as a vibration tamper, is provided. The compacting machine includes an internal combustion engine for driving a compacting plate and at least one guide bar for holding and/or guiding the soil compacting machine.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to foreign Patent Application DE 10 2009 017209.2, filed on Apr. 9, 2009, the disclosure of which is incorporated herein by reference in its entirety. 
       FIELD OF THE INVENTION 
       [0002]    The invention relates to a hand-guided soil compaction machine and, especially, a vibration tamper for soil compaction. 
       BACKGROUND OF THE INVENTION 
       [0003]    One known soil compaction machine includes a superstructure with an internal combustion engine which drives a compacting plate belonging to a substructure via a crank mechanism or the like, with which soil or the like can be compacted. A handlebar is arranged on the superstructure, with which a user can keep the tamper in operation and/or can guide the same. 
         [0004]    One known tamper or vibration tamper with a low-vibration guide bar includes a superstructure, or an upper mass, and a substructure, or a lower mass. The total mass and especially the mass ratio of superstructure to substructure have a relevant influence on the effectiveness and the convenience in operation of a soil compaction machine, and especially a vibration tamper. 
       SUMMARY OF THE INVENTION 
       [0005]    Embodiments of the present invention advantageously reduce the overall mass of a hand-guided soil-compaction machine with an internal combustion engine. 
         [0006]    In accordance with one embodiment of the present the invention, a soil compaction machine comprises an internal combustion engine for driving a compacting plate and at least one guide bar for holding and/or guiding the soil compaction machine, with the guide bar comprising a flow channel through which a supply of the combustion air to the internal combustion engine occurs at least in sections. 
         [0007]    The guide bar thus assumes a conducting function in accordance with the invention in addition to the mere holding and guiding function, which is the conduction of the combustion air. This advantageously allows for a reduction in weight or mass, especially in the superstructure of the soil compacting machine. Furthermore, there is a reduction in the overall size and reduction in individual parts. As a result of new constructional degrees of freedom, it is further possible to use air-filter types whose use was previously not possible. As a result of the spatial spacing of air filter and internal combustion engine which is bridged by means of the flow channel, the combustion air can be drawn in a region in which the thermal loading and/or the dust exposure is low. Moreover, heating up of the air filter or the air-filter housing by heat conduction and/or heated engine cooling air by the internal combustion engine can be prevented. 
         [0008]    The combustion air is used for the combustion process in the internal combustion engine. It expressly does not concern the exhaust gases from the combustion process. Preferably, the flow of the combustion air is caused by the intake process of the internal combustion engine. 
         [0009]    An advantageous further development of the invention provides that the flow channel is arranged to be integrated in the guide bar. As described herein, this integrated arrangement (“integrated flow channel”) comprises a defined flow route or flow path which is fixedly connected with the guide bar, which flow path is suitable to pass through at least a part of the combustion air to bridge a distance. Preferably, this flow path follows the contour of the guide bar at least in sections. 
         [0010]    A soil compacting machine in accordance with another aspect of the present invention is a tamping device or a vibration tamper with a tamping plate or the like which is driven by means of the internal combustion engine. This aspect of the invention is not exclusively limited to such tamping devices, but can advantageously be implemented in all hand-guided soil compacting machines with an internal combustion engine and a guide bar such as a vibration plate for example. 
         [0011]    It is provided according to a preferred further development that the guide bar is formed by a hollow section at least in sections whose hollow space forms the integrated flow channel. The guide bar can comprise for this purpose a metal material and/or a plastic material and/or a composite material. The term “hollow section” also comprises multi-chamber sections within the terms of the invention. The axial longitudinal extension of the hollow section can be straight and/or spatially curved. In particular, the guide bar is made at least in sections of a bent or multi-component tube of a random and especially circular cross section. 
         [0012]    It is provided according to a preferred further development that further functional means are arranged on the guide bar, such as especially an air-filter unit which is in flow connection with the integrated flow channel. Said air-filter unit preferably comprises an air filter and is used for cleaning the combustion air. One fundamental idea of this further development is to provide several additional functions to the guide bar in addition to the further conducting of combustion air. 
         [0013]    The realization of the flow connection between an air-filter unit on the guide bar and the integrated flow channel is achieved in an especially elegant manner by means of a connecting flange. This connecting flange is preferably arranged as a separate component and can be L-shaped or T-shaped for example. 
         [0014]    In a further advantageous further development, the guide bar is arranged on or fastened to the soil compacting machine in a vibration-dampened or vibration-insulated manner. Preferably, the guide bar is further arranged on a frame of the superstructure of the soil compacting machine which also accommodates the internal combustion engine. The term “frame” shall be interpreted in a broad fashion and shall also comprise a self-supporting construction of the internal combustion engine. 
         [0015]    At least one elastic damping element may be present for vibration insulation or damping of the guide bar, which damping element also allows the conduction of the combustion air. The damping element thus assumes a multiple function in this embodiment of the invention (conduction of the combustion air and vibration damping). 
         [0016]    The damping element may be arranged as a rubber buffer with at least one bore hole, preferably an axial bore hole, for conducting the combustion air. The combustion air can be conducted through this bore hole. In this case, the integrated flow channel thus opens at least on one side into the rubber buffer. A rubber buffer is characterized by its rubber-elastic properties. Preferably, a rubber buffer is made of a natural material or an artificial material. This also includes elastic silicone materials. 
         [0017]    It is provided according to a preferred further development that the flow connection between the integrated flow channel and the bore hole in the rubber buffer is realized by means of a connecting flange. This connecting flange may be arranged as a separate component which can be arranged in an L-shaped or T-shaped manner. In particular, this component can also be identical to the one for flow connection between the air-filter unit and the integrated flow channel. 
         [0018]    A fuel tank may also be further arranged on the guide bar. This offers the advantage for example of a similarly vibration-dampened suspension of the fuel tank. One fundamental idea of this further development is also to provide several additional functions to the guide bar in addition to the further conducting of combustion air. 
         [0019]    It is also provided that the air-filter unit and the fuel tank are arranged in a common housing. This will be explained be-low in closer detail in connection with the drawings. The term “housing” also comprises holding apparatuses and the like which are capable of fastening the fuel tank and the air-filter unit to the guide bar. This allows for further reduction in overall space in an outstanding way and a further reduction of individual parts. This arrangement of an air-filter unit and a fuel tank in a common housing on an initially mentioned soil compacting machine and especially on its guide bar can also occur independently from a guide bar with a flow channel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    The invention will be explained below in closer detail by reference to the drawings, with the same reference numerals indicating the same components, with the drawings showing schematically: 
           [0021]      FIG. 1  shows a soil compacting machine according to the state of the art in a perspective view; 
           [0022]      FIG. 2  shows the superstructure of a soil compacting machine according to an embodiment of the present the invention in a perspective view; and 
           [0023]      FIG. 3  shows a top view of the soil compacting machine of  FIG. 2  in a partial sectional view. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    In accordance with  FIG. 1 , a generic soil compacting machine which is known from the state of the art and is arranged as a vibration tamper  10  comprises a substructure  20  and a superstructure  30 . The substructure  20  comprises a compacting plate or tamping plate  21  and the superstructure  30  an internal combustion engine  31  with an air-filter unit  32 , a fuel tank  33  and a guide bar  34 . The internal combustion engine  31  drives the compacting plate  21  in a manner known from the state of the art via a crank mechanism (not shown) which is arranged partly behind the cover plate  50 . 
         [0025]    Aspects that are relevant to the invention will be explained below by reference to  FIGS. 2 and 3 . 
         [0026]      FIG. 2  shows, among other things, the superstructure  30  of the vibration tamper  10 . The superstructure  30  comprises an internal combustion engine  31  and guide bar  34 ′ in accordance with the invention. The guide bar  34 ′ offers various handling features for a user in order to enable keeping the vibration tamper  10  in operation or to guide the same. The guide bar  34 ′ is arranged in a vibration-dampened or vibration-insulated manner at two fastening points via the damping elements  35   a  and  35   b  on a frame of the superstructure  30 . It is understood that also any other number of fastening points could be provided. The damping elements  35   a  and  35   b  are arranged as integral rubber buffers. It is understood that also a multi-part arrangement of these damping elements  35   a  and  35   b  would be possible. 
         [0027]    An air-filter unit  32  and a fuel tank  33  are fastened in a common housing  40  to the guide bar  34 ′. As a result of this special manner of arrangement on the guide bar  34 ′, the air-filter unit  32  and the fuel tank  33  are thus also arranged in a vibration-dampened or vibration-insulated manner on the vibration tamper  10 . A common housing  40  further allows simple and rapid mounting or dismounting of these components and further leads to a reduction in weight. The cover over the air-filter unit  32  has been removed for the purpose of better illustration. In the separating area between the air-filter unit  32  and the fuel tank  33 , the common housing  40  is arranged with a double wall with an air gap. When seen from the internal combustion engine  31 , the air-filter unit is arranged substantially before the fuel tank  33  in the common housing  40 . It is alternatively possible to arrange the air-filter unit  32  also behind the fuel tank  33 . It is understood that the air-filter unit  32  and the fuel tank  33  can also be arranged as separate components on the guide bar  34 ′, i.e. without any common housing  40 . 
         [0028]    The combustion air required for the combustion process in the internal combustion engine  31  is supplied, and especially drawn in, via the air-filter unit  32 . It is now provided in accordance with the invention that this supplied combustion air flows from the air-filter unit  32  to the internal combustion engine  31  via a section of the guide bar  34 ′ which is designated with  34 A. The direction of through-flow is indicated with the arrow shown in  FIG. 2 . This section  34 A of the guide bar  34 ′ thus comprises an integrated flow channel. 
         [0029]    For this purpose, at least this section  34 A of the guide bar  34 ′ is arranged as a hollow section, with the cavity representing the integrated flow channel. In the illustrated embodiment, the hollow section is realized by a tube with a circular cross section, with other shapes of cross sections being possible. The integrated flow channel extends in the present case from a fastening point of the air-filter unit  32  up to a fastening point of the guide bar  34 ′ on the frame of the superstructure  30 . In the region of the section  34 A, the flow channel has a straight axial expansion. The flow channel  34 A can also have any desired curved axial extension, irrespective of the respective arrangement of the guide bar  34 ′. 
         [0030]    The combustion air is introduced into the integrated flow channel at the fastening point of the air-filter unit  32  at the guide bar  34 ′ and guided out of the same at the fastening point of the guide bar  34 ′ on the frame of the superstructure  30 . As an alternative to this or in addition, the combustion air can principally flow on other flow paths through the guide bar  34 ′, with short and substantially straight flow paths being preferable. 
         [0031]    The introduction of the combustion air into the integrated flow channel occurs by means of a separate connecting flange  37 . The connecting flange  37  is thus arranged in such a way that a flow connection (i.e. a connection through which the combustion air can flow from the air-filter unit  32  into the integrated flow channel) is produced between the flow channel integrated in the guide bar  34 ′ or  34 A and the air-filter unit  32 . This connecting flange  37  can also be designated as a connecting flange  37  on the air-filter side. 
         [0032]    The discharge of the combustion air from the integrated flow channel occurs through the damping element  35   a.  It is provided for this purpose in accordance with  FIG. 3  with an axial, circular-cylindrical and central bore hole  36   a.  The discharge through the damping element  35   a  occurs via a connecting flange  38  which connects at least the section  34 A of the guide bar  34 ′ with the damping element  35   a  in the manner that a respective flow connection is obtained. This connecting flange  38  can also be designated as the connecting flange  38  on the motor side. The flow through section  34 A of the guide bar  34 ′ and the discharge through the axial bore hole  36   a  in the damping element  35   a  is shown schematically in  FIG. 3  with the flow arrows. 
         [0033]    The section  34 A of the guide bar  34 ′ which is disposed between the connecting flanges  37  and  38  can preferably have a larger diameter, and especially a larger inside diameter, than the other sections of guide bar  34 ′. The section  34 A is especially arranged as a separate straight pipe section. It can also be provided to arrange only this section  34 A as a hollow section. 
         [0034]    The combustion air is guided from the damping element  35   a  to the internal combustion engine  31  by means of a separate flow connection or a flexible air hose  39 . It is alternatively possible to forward the flowing air through an integrated flow channel within the frame of superstructure  30 . The damping element  35   a  is used both for damping or insulating vibrations of the guide bar  34 ′ and the conduction or transmission of the combustion air. Moreover, the damping element  35   a  provides sealing in the connecting area and prevents the intake of secondary air. The damping element  35   a  thus assumes a multiple function. 
         [0035]    The flow channel integrated in the guide bar  34 ′ or  34 A advantageously enables a reduction in weight or mass, especially in the superstructure  30  of the vibration tamper  10 . It is thus possible to omit the entire air-filter housing as shown in  FIG. 1  for example. This leads to a reduction in overall space and individual parts. Moreover, performed measurements having not shown any reduction in the engine output. 
         [0036]    The many features and advantages of the invention are apparent from the detailed specification, and, thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and, accordingly, all suitable modifications and equivalents may be resorted to that fall within the scope of the invention.