Patent Publication Number: US-8523480-B2

Title: Soil compaction device having a disconnectable fuel line

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a submission under 35 U.S.C. §371 of International Application No. PCT/EP2011/000309, filed Jan. 25, 2011, which claims priority to German Application No. 10 2010 005 597.2, filed Jan. 25, 2010, the disclosures of which are hereby expressly incorporated by reference herein in their entireties. 
     FIELD OF THE INVENTION 
     The present invention relates to a soil compaction device with an internal combustion engine and a tank container for receiving fuel for the operation of the internal combustion engine. The soil compaction device preferably is a hand-operated soil compaction device such as a tamper, a vibration plate device or the like. 
     BACKGROUND OF THE INVENTION 
     During transport or prolonged storage of such a soil compaction device, fuel from the tank container can reach the internal combustion engine, which is undesirable. Especially susceptible are internal combustion engines with a diaphragm carburetor device, since fuel will be aspirated by the diaphragm carburetor device during vibrations and will be conveyed into the internal combustion engine. It is therefore known to provide a so-called shut-off valve (gasoline shut-off), with which a fuel flow from the tank container to the internal combustion engine or its carburetor device can be interrupted. Such fuel shut-off valves are frequently not used in practice. The combination of a manually actuated gas actuation device for controlling the speed or power of the internal combustion engine with a fuel valve is known from the state of the art (cf. DE 195 49 113 C1). The valve will be automatically opened and closed by actuating the gas actuation device. Such solutions are susceptible to malfunctions, however, which has a disadvantageous effect on the operational reliability. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a soil compaction device with which a high level of operational reliability can be ensured. 
     The soil compaction device according to one embodiment of the present invention comprises an internal combustion engine and a tank container for receiving fuel such as gasoline for the operation of the internal combustion engine. The soil compaction device further comprises a manually actuated gas actuation device and/or a manually actuated start-stop device for the internal combustion engine. Furthermore, the soil compaction device in accordance with one embodiment of the present invention comprises at least one clamping device which mechanically (i.e., without any electrical actuating components) acts on at least one elastically flexible section of a fuel line which is arranged between the tank container and the internal combustion engine or the tank container and a carburetor device belonging to the internal combustion engine and which connects the same, this being in order to interrupt the fuel flow or through-flow through the fuel line and to especially disconnect the flow. It is provided that the clamping device is mechanically coupled with or integrated in the gas actuation device and/or the start-stop device. 
     The clamping occurs when the flexible section of the fuel line is compressed or squeezed by application of a force (clamping force) at a position provided for this purpose for interrupting the fuel flow. After removing the force, the compressed region of the fuel line will expand again as a result of elastic restoring forces and will release the fuel flow again. Whereas the valve devices known from the prior art are highly sensitive to shocks, vibrations and gumming (which leads to leakages, for example), the solution in accordance with the principles of the present invention is advantageously characterized in that it is robust in numerous ways. Furthermore, an undesirable fuel flow can reliably be interrupted, so that the operational reliability of the soil compaction device is increased considerably. Furthermore, a valve device as known from the prior art as described above can be omitted, so that costs can be saved. The proposed solution is convincingly simple which requires only few components and is extremely robust. 
     A clamping device shall be understood as being a single one or a plurality of cooperating elements or components which are able to produce a clamping of the fuel line in the region of the elastically flexible section. According to one embodiment, the clamping comprises at least one movable clamping element exerting the clamping force, mechanically acting either directly or indirectly on the elastically flexible section of the fuel line and being capable of producing the clamping, and at least one element constituting the counterforce, which is especially arranged in a rigid and immobile manner. The flexibly elastic section of the fuel line in which the clamping occurs is arranged at least in sections between the effective areas of the corresponding elements. 
     The flexible section preferably comprises a hose section which is made of a fuel-resistant and weatherproof material. In the case of aging or material fatigue, the respective section can be exchanged rapidly and easily even by untrained staff on site, e.g., at the construction site. This also contributes to an increased operational reliability of the soil compaction device. 
     According to the present invention, the clamping device is mechanically coupled with a manually actuated gas actuation device for setting the power or the speed of the internal combustion engine and/or with a manually actuated start-stop device providing a start-stop function of the internal combustion engine, or is integrated in said devices. A gas actuation device and a start-stop device can be arranged as one common or combined device. It is preferably provided that the gas actuation device and/or the start-stop device has at least one operating position or starting position in which the internal combustion engine is in operation or can be started, with the fuel flow from the tank container to the internal combustion engine being released, and at least one stop position in which the internal combustion engine is in the deactivated idle state and the fuel flow from the tank container to the internal combustion engine is interrupted. It is provided that, when the internal combustion engine is switched off, the fuel flow to the internal combustion engine is automatically and mechanically (i.e., especially without any electrical actuating components) interrupted by means of the clamping device by manually moving the gas actuation device and/or the start-stop device from the operating position or starting position to the stop position. 
     According to one embodiment of the present invention, the gas actuation device and/or the start-stop device comprises a pivotable actuating lever (gas lever and/or on-off lever) or the like which can be manually actuated by the operator and which is able to mechanically act on the elastically flexible section of the fuel line via a lever in order to disconnect the fuel flow through the fuel line. The lever mechanism is simply formed by an extension of the actuating lever protruding beyond the pivot joint. Preferably, the actuating lever is integrally arranged with the extension. The extension can act either directly or indirectly on the elastically flexible section of the fuel line in order to produce the clamping. It is provided that, for the indirect clamping, at least one roll or roller is arranged on the extension, which roll or roller acts on the elastically flexible section of the fuel line in order to enable disconnecting the fuel flow through the fuel line. Excessive frictional and thrust forces on the outside jacket of the fuel line can be avoided by using a roll or a roller, which forces could lead to wear and tear and to damage. The roll or the roller is therefore used as a wear-reducing element. 
     According to one embodiment of the present invention, the actuating lever is provided with at least one cam which is able to mechanically act in a direct or indirect manner on the elastically flexible section of the fuel line in order to interrupt the fuel flow through the fuel line. Preferably, the actuating lever is integrally arranged with the cam. It is provided that at least one pressure element is comprised which is movable relative to the elastically flexible section of the fuel line, that a clamping force applied by the cam is transmitted in a friction-free manner onto the elastically flexible section of the fuel line in order to thereby disconnect the fuel flow through the fuel line. A direct frictional contact between the cam and the elastically flexible section of the fuel line is prevented by means of such a force-transmitting element. The force-transmitting element is therefore also used as a wear-reducing element. This will be described below in closer detail in connection with the drawings. 
     According to one embodiment of the present invention, the clamping device is arranged in order to enable a point-like clamping of the elastically flexible section of the fuel line. Alternatively, and/or additionally, the clamping device is arranged to enable clamping of the elastically flexible section of the fuel line along a length section or flat clamping. It is similarly preferably provided that the clamping device is arranged to enable multiple clamping, e.g., at different places of the elastically flexible section of the fuel line. 
     According to one embodiment of the present invention, the clamping device is arranged to clamp and subsequently release at least one elastically flexible section of a fuel line arranged between the tank container and the internal combustion engine, and simultaneously at least one vent line. Such a vent line is connected to an air port and/or vent hole of the tank container. The escape of fuel during the deactivated internal combustion engine, e.g., during the transport of the soil compaction device, can thus effectively be prevented, while the required venting of the tank container in operation remains ensured. The simultaneous closing of the vent line also prevents the escape of hazardous fuel vapors. More than two lines can be disconnected according to the same principle. 
     According to one embodiment of the present invention, the clamping device, especially including all relevant components, is arranged on a frame construction such as especially a handle device (hand grip) of the soil compaction device. Preferably, the fuel line (especially the elastically flexible section) is arranged at least in sections on the frame construction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be described below in a non-limiting way by reference to preferred embodiments shown in the drawings, wherein: 
         FIG. 1  shows a soil compaction device in a perspective view; 
         FIGS. 2   a  and  2   b  show a first embodiment of a clamping device in two schematic views; 
         FIGS. 3   a - 3   c  show a second embodiment of a clamping device in several perspective views; and 
         FIG. 4  shows a third embodiment of a clamping device in a perspective view. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments are shown and described in connection with a gas actuation device. Instead of such a gas actuation device, it is also possible to provide in an analogous fashion a start-stop device or a combined device (gas actuation function and start-stop function), as described above. 
       FIG. 1  shows a soil compaction device  10  known from the prior art and is arranged as a tamper. The soil compaction device  10  comprises a lower structure  20  with a tamping plate  21  and an upper structure  30 . The upper structure  30  comprises an internal combustion engine  31  for driving the tamping plate  21  and a tank container  32  for receiving fuel for the operation of the internal combustion engine  31 . The upper structure  30  also includes a protective frame construction  33  which is simultaneously used as a handle device or a handgrip for a user. A gas actuation device  40 , which can be manually actuated, is attached to the frame construction  33  for setting the speed of power of the internal combustion engine  31 . The gas actuation device  40  is coupled in accordance with the present invention with a clamping device for interrupting the fuel flow from the tank container  32  to the internal combustion engine  31 , as will be described below. 
       FIG. 2  schematically shows such a gas actuation device  40  with an actuating lever or gas lever  41  which can manually be brought to different positions.  FIG. 2   a  shows the actuating lever  41  in an operating position and  FIG. 2   b  shows the same actuating lever  41  in a stop position. An idle position (not shown) can be provided between these positions. The actuating lever  41  is pivotably mounted on a fixing device  60  by means of a pivot joint  42 . The position of the actuating lever  41  is transmitted by means of a rod assembly or a Bowden cable  45  to a carburetor device of the internal combustion engine  31 , by means of which the speed and/or the power of the internal combustion engine  31  can be set as required. 
     Furthermore, the internal combustion engine  31  can also be switched off or deactivated by means of the actuating lever  41 . For this purpose, the actuating lever  41  is moved from the operating position as shown in  FIG. 2   a  to the stop position as shown in  FIG. 2   b , which is indicated with the movement arrow A. In this process, a section of the fuel line which is designated with reference numeral  50  and which connects the tank container  32  with internal combustion and  31  is pressed against a rigid clamping jaw  61  and is compressed or squeezed in this process, by means of which the fuel flow from the tank container  32  to the internal combustion engine  31  is effectively interrupted or disconnected. It can be prevented in this process that fuel will continue to reach the engine or its carburetor device in the deactivated state, which is undesirable. 
     The clamping of the section  50  of the fuel line occurs by means of a clamping device. For this purpose, the actuating lever  41  is provided with an extension  43  which protrudes beyond the pivot joint  42  and is bent off in this example, and on the axial end of which a rotatable roller  46  is arranged. When the actuating lever  41  is moved to the stop position (arrow A), the section  50  of the fuel line is compressed in a kinematic fashion by means of the roller  46 . The roller  46  prevents excessive frictional and/or thrust forces as a result of the relative movement between the extension  43  of the actuating lever  41  and the outside jacket of the section  50  of the fuel line. 
     When the actuating lever  41  is moved from the stop position ( FIG. 2   b ) to an operating position, which is indicated with the movement arrow B, the clamping of the section  50  will be removed. As a result of the relief of forces, the compressed region of the fuel line will expand as a result of elastic restoring forces and will release the fuel flow again, whereupon the internal combustion engine can be started and operated again. It is, therefore, necessary that at least the section  50  of the fuel line in which the clamping occurs is made of an elastically flexible material. 
       FIG. 3  shows another embodiment of the present invention. The same components and/or components with the same function are designated with the same reference numerals. The illustrations show the same actuating lever  41  in a first operating position ( FIG. 3   a ), in a second operating position or idle or start position ( FIG. 3   b ), and in a stop position ( FIG. 3   c ). Only the relevant differences compared to the first embodiment of  FIG. 2 , will be described below. 
     Deviating from the first embodiment of  FIG. 2 , the actuating lever  41  is provided with an eccentric cam  44  which in the stop position ( FIG. 3   c ) presses the flexibly elastic section  50  of the fuel line against the rigid clamping jaw  61  by means of a movable pressure element or clamping element  70 , by means of which the fuel flow through the fuel line is disconnected. The movable pressure element  70  transmits the clamping force applied by the cam  44  and simultaneously absorbs the frictional and/or thrust forces resulting from the relative movement. The movable pressure element  70  further allows planar clamping, by means of which the fuel flow can be interrupted in a very reliable way. The pressure element which is arranged as a simple shaped sheet metal part and which is movably mounted is guided on the clamping jaw  61  in a loss-proof manner and is able to move transversely to the longitudinal extension direction L of the section  50  of the fuel line. The restoring movement after the relief of forces will be produced by the elastic restoring forces of the section  50  of the fuel line. The rigid clamping jaw  61  is fixed by means of screws  62  to the fixing device  60 , so that the entire gas actuating device  40  can be mounted as a unit together with the clamping device in that the fixing device  60  is fixed to the frame construction  33 , for example. 
       FIG. 4  shows a further embodiment of the present invention. The same components and/or components with the same function are designated with the same reference numerals. The illustration shows the actuating lever  41  in a first operating position which corresponds to the operating position as shown in  FIG. 3   a . Only the relevant differences compared to the second embodiment of  FIG. 3 , will be described below. 
     Deviating from the second embodiment of  FIG. 3 , two line sections  50  and  51  are arranged between the movable pressure element  70  and the clamping jaw  61 . The section  50  concerns a section of the fuel line which connects the tank container  32  with the internal combustion engine  31 , as already described above. The section  51  concerns the section of a vent line which is used for venting and/or airing the tank container  32 . Both line sections  50  and  51  are simultaneously clamped by means of the cam  44  and the movable clamping element  70  when the actuating lever  41  is moved from the illustrated operating position in the direction A to a stop position. This can also help effectively prevent the undesirable escape of fuel and/or fuel vapors through the tank venting system, for example. 
     The features of the previously described embodiments can be combined with one another as long as they are not technically contradicting. Furthermore, a previously described clamping device can also be arranged as a single measure, i.e., without the mechanical coupling with a gas actuating device. 
     While the present invention has been illustrated by description of various embodiments and while those embodiments have been described in considerable detail, it is not the intention of applicant to restrict or in any way limit the scope of the appended claims to such details. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of Applicant&#39;s invention.