Patent Application
20120282027
The present application claims priority under 35 U.S.C. §119 of German Patent Application No. DE 10 2011 100 155.0, filed May 2, 2011, the disclosure of which is hereby incorporated herein by reference in its entirety.
The present invention relates to an actuating device for a soil compaction device with an internal combustion engine, especially for a vibration tamper, which is used for joint actuation of an engine stop switch and a tank shut-off valve, and a soil compaction device with such an actuating device.
In the case of a soil compaction device with an internal combustion engine, fuel from the fuel tank can reach the internal combustion engine during transport or prolonged storage, which is undesirable. This is especially the case for internal combustion engines with a diaphragm carburetor device, since fuel is aspirated by the diaphragm carburetor device during shaking and is conveyed into the internal combustion engine, which can lead to considerable starting difficulties for example. It is therefore known to provide a tank shut-off valve with which the flow of fuel from the fuel tank to the internal combustion engine or its carburetor device can be interrupted. Furthermore, the integration of an engine stop switch in a soil compaction device is known. The engine stop switch is arranged in a manner that it interrupts the power supply of the ignition circuit in one position (“engine-off position”), by means of which operation of the internal combustion engine is excluded, and closes the ignition circuit in another position (“closed position”), which enables the operation of the internal combustion engine. If the interruption of the ignition circuit occurs during running operation of the internal combustion engine, an actuation of the engine stop switch will accordingly lead to an immediate engine stop. On the other hand, starting of the internal combustion engine is not possible as long as the engine stop switch is in its “interrupted position”.
An actuating device is known from DE 195 49 113 C1, with which both an engine stop switch and a tank shut-off valve can be actuated successively. This actuating device comprises an actuating member in form of a pivoting lever which can selectively be pivoted between different operating positions and a stop position which will stop the internal combustion engine. When the pivoting lever is pivoted to the stop position, the tank shut-off valve will be closed directly by way of a cam arranged on the pivoting lever. Furthermore, the engine stop switch will be actuated upstream via a Bowden cable, which leads to an immediate stop of the internal combustion engine in that the ignition is short-circuited for example. By pivoting the pivoting lever from the stop position, the tank shut-off valve will be opened again and the actuation of the engine stop switch will be removed, so that the internal combustion engine can be started. The prior known actuating device is susceptible to malfunction and frequently leads to the consequence that the engine is inadvertently switched off when the operating lever is moved beyond its idle position to the engine stop position.
It is therefore an object of the present invention to provide a simple and sturdy actuating device for a soil compaction device, which on the one hand ensures a reliable cut-off of the internal combustion engine and simultaneously offers increased operating convenience.
According to one aspect of the present invention, two actuating means or elements are provided for operating the soil compaction device, which actuating means or elements are respectively associated with different operating functions. The first actuating element is provided in a known manner for regulating the engine power between an idle state and a full throttle state. In other words, the first actuating element is a throttle lever via which the engine power can be adjusted between idling and full throttle. The operator can control the working intensity of the soil compaction device with a running internal combustion engine via a respective adjustment of the first actuating element.
In accordance with one embodiment of the present invention, the entire actuating device also comprises a separate second actuating means or element in addition to the first actuating element, via which a manual control of the operating functions is provided, which specifically relates to the control of a tank shut-off valve and an engine stop switch. The fuel supply from the tank to the internal combustion engine can be interrupted and released by a control of the tank shut-off valve. The control of the engine stop switch on the other hand allows producing or interrupting the power supply to the internal combustion engine, e.g., for supplying the ignition circuit. The second actuating element is therefore used for the purpose of switching the soil compaction device back and forth between a state that is “ready for operation” and a state of “no operation”, whereas the first actuating element is used for regulating the operating state of “ready for operation” and “in operation”. The first and the second actuating element of the actuating device can be controlled separately from one another, with a regulation of the throttle via the first actuating element obviously only making sense when the internal combustion engine is running.
It is possible that further control functions are co-controlled via the actuating device and especially also via the second actuating element. However, it has proven to be advantageous in one embodiment to use the second actuating element exclusively for actuating the tank shut-off valve and the engine stop switch. It is ensured in this manner that there is a clear separation for the operation between the states of “ready for operation”/“in operation” and “no operation”/“engine off”.
In one embodiment, the second actuating means or element is arranged in a manner that it actuates the tank shut-off valve and the engine stop switch at least substantially simultaneously, especially when adjusting its position from “ready for operation” in the direction towards “no operation”, with a respective configuration for the reversed switching path also being possible in a supplementary or alternative manner. The terminology of “substantially simultaneously” shall be understood in such a way to mean that the changeover of the tank shut-off valve and the engine stop switch occurs in a virtually simultaneous manner in case of a manual actuation of the second actuating element by an operator. According to one aspect of the present invention, the change over of the tank shut-off valve and the engine stop switch may occur simultaneously in a manner as precisely as possible. The operator therefore merely needs to overcome a switching point with the second actuating means in order to trigger the two functions of “interruption”/“release” depending on the direction of actuation by the tank shut-off valve and “actuation”/“release” of the engine stop switch. It will be understood that marginal tolerances can occur that are caused by production. The relevant aspect for the simultaneous occurrence of the actuation is that both the engine stop switch and the tank shut-off valve are actuated virtually simultaneously, especially with respect to the entire actuating path of the second actuating means, and/or, depending on the embodiment, are released.
Principally, the particular configuration of the second actuating means can vary over a wide spectrum. In one embodiment, it is arranged for the direct actuation of the engine stop switch and/or the tank shut-off valve in order to avoid complex transmission devices. A direct actuation is provided when the second actuating means directly triggers the engine stop switch and/or the tank shut-off valve. Principally, an arrangement of the second actuating means close to the engine stop switch and/or the tank shut-off valve, especially as a compact and connected unit, has proven to be advantageous.
Considering the numerous configuration alternatives that may be considered such as rocking levers, thrust levers, etc., the arrangement of the second actuating means in form of a rotary lever, which will also be designated below as a rotary switch, has proven to be advantageous. A rotary switch is characterized in that it is twisted or rotated for switching or actuation and therefore requires very little space. A rotary switch is further especially suitable for transmitting actuating forces from the second actuating means in a suitable manner to the tank shut-off valve and the engine stop switch.
In order to enable a manual control of the rotary switch, it may comprise a grip end in form of a protruding beam for example. For the purpose of transmitting the switching motion, this embodiment further preferably comprises a shaft which is connected with the grip end in a torsion-proof manner, wherein both the tank shut-off valve and also the engine stop switch can be actuated indirectly or especially directly via the shaft. A shaft shall generally be understood in the present case as being an element of random cross-section which is rotatable about a rotational axis and is capable of transmitting rotational movements and rotational forces (torques), especially in the manner as will be described below in closer detail. As a result of the torque-proof connection of the grip end with the shaft, the shaft will co-rotate during a rotational actuation of the grip end. This movement will be utilized in the present case to actuate the engine stop switch and the tank shut-off valve together and in a substantially simultaneous manner. When the rotary grip end is pivoted to the engine stop position while the internal combustion engine is running, the tank shut-off valve on the one hand will therefore be closed virtually in the same moment or on exceeding a common switching point, whereupon the fuel connection from the fuel tank to the internal combustion engine will be interrupted, and on the other hand the internal combustion will be switched off by the engine stop switch, which can occur by interrupting the ignition circuit for example. When the rotary grip end is twisted or rotated back from the engine stop position to an operating position, the tank shut-off valve will be opened and the interruption of the ignition circuit will be removed, whereupon the internal combustion engine is started and can be operated. The second actuating means can be arranged in a manner that actuation of the engine stop switch and the tank shut-off valve in the one direction of actuation (i.e., from the engine off position in which the engine stop switch interrupts the ignition circuit and the tank shut-off valve interrupts the fuel supply, to the operating position, in which the engine stop switch closes the ignition circuit and the tank shut-off valve releases the fuel supply from the fuel tank to the internal combustion engine or carburetor), or in the other direction of actuation (from the operating position to the engine off position), and preferably in both switching directions, switches over the engine stop switch and the tank shut-off valve virtually simultaneously or upon exceeding a respectively common switching point. This enables the simultaneous triggering of the respective control processes by the tank shut-off valve and the engine stop switch, which therefore ensures, for example, depending on the respective embodiment, that the fuel supply is interrupted simultaneously with the cut-off of the internal combustion engine and/or vice versa. This leads to the advantage for the operator that both control functions are performed with one adjustment. Furthermore, intermediate positions between a changeover of the engine stop switch and an actuation of the tank shut-off valve will no longer occur.
The shaft of the rotary switch can be used on the one hand for bearing the rotary switch. In one embodiment, the shaft comprises a co-rotating contact device which is arranged for actuating the engine stop switch and/or the tank shut-off valve. Correspondingly, the shaft preferably comprises a co-moved contact device for contacting or even contactless actuation, especially for the engine stop switch. The engine stop switch can be arranged as a touch contact, for example, for contacting actuation. It can be provided for this purpose that the engine stop switch will interrupt the ignition circuit in the pressed state and close the engine stop switch in the non-pressed state. For contactless actuation, the engine stop switch can be arranged as a magnetic switch or reed contact switch.
An arrangement of the contact device in the form of a control surface has proven to be especially advantageous in practical use. It is especially suitable for controlling the engine stop switch which is frequently arranged as a touch contact. The control surface designates a surface along which a member to be controlled, such as the sensing head of a touch contact, is moved during an actuation movement of the second actuating means. Specifically, arrangements of the contact surface as a radially curved area, or as an area which is eccentric with respect to the rotational axis, or as cams in the rotational plane of the rotary switch, have proven to be especially suitable. In this embodiment, the touch contact, which is usually pressurized by a pressure spring, rests on the control surface and is pressed in beyond its switching point as a result of the special arrangement of the control surface when actuating the rotary switch or, depending on the direction of rotation, is pressed out, or a return is enabled by the restoring force provided internally in the switch. A switching point shall designate a point in the switching motion of the touch contact, at which, when exceeded, it will move from its one switching position (e.g., its position interrupting the ignition circuit) to its other position (e.g., its position closing the ignition circuit). The control surface can be arranged as a radially curved area. A radially curved area is characterized in that it comprises changing distances to the rotational axis in a plane orthogonally to the rotational axis of the rotary switch in the radial direction, wherein especially flowing changes in the distance are advantageous in order to enable the smoothest possible switching process.
In one embodiment, the control surface and the element actuated by the control surface, especially the engine stop switch arranged as a touch contact, are arranged in the manner with respect to one another that the control surface adjusts the engine stop switch orthogonally to the rotational axis of the shaft. This ensures an especially efficient transmission of the rotating actuating movement of the second actuating means to the engine stop switch.
The control surface is therefore preferably arranged as a contact area which co-rotates with the shaft, thereby enabling a contacting actuation of the engine stop switch during a rotational movement of the rotary lever. Alternatively, a contactless actuation can also be provided, e.g., by means of a reed contact. In both cases, the contact device will co-rotate with the shaft.
As an alternative or in addition to a contact area acting in the radial direction of the rotary shaft, it is also possible, for example, that the rotatable shaft is axially displaced simultaneously with the rotation about the rotational axis, which can be achieved by a rotational adjusting mechanism (such as a power-transmission thread or the like). In this case the actuation of the engine stop switch or the tank shut-off valve can occur in the axial direction of the shaft. Both embodiments (actuation in the radial direction and actuation in the axial direction) can also be combined with one another.
The triggering of the tank shut-off valve is also principally variable. A mechanical actuation—especially with the help of an actuating device which co-moves with the rotary lever—is advantageous in order to achieve reliable operation of the actuating device. One implementation of the present invention provides that a connecting device is provided at the bottom axial end of the shaft (i.e., at the end of the shaft opposite of the rotary lever) which is arranged in a manner that it transmits a rotational movement of the rotary lever to a rotary valve of the tank shut-off valve. A rotary valve is characterized in this case in that it can be moved by a rotational movement between an opened and a closed position. For this purpose, the shaft can be linked to a ball valve which is incorporated in the fuel line, with the linkage being made in a direct manner or also by a suitable connecting device. It may be advantageous for reasons of space if the rotational axes of the rotary lever and the rotary valve are disposed coaxially with respect to each other. This is achieved in a very positive way when the rotary valve is adjacent to a face end of the shaft. It is alternatively possible that the tank shut-off valve is actuated by means of a slide or the like which is actuated by the rotational shaft, so that tank shut-off valves without rotary valves can be used as well. Of course electrically actuatable valves or further alternative valves can also be used.
The linkage of the shaft to the respective actuating component of the tank shut-off valve preferably occurs by means of a positive and/or non-positive connection. As a result, the shaft can contain a receiving recess directed in the radial direction for example in which a rotatable part of the tank shut-off valve, e.g., a projection in the valve ball of a ball valve, will engage.
The second actuating means, especially in form of the rotary switch, is further preferably mounted in a relatively movable manner in a housing. An extremely compact modular unit can thereby be obtained. This applies especially for an arrangement of the second actuating means as a rotary lever with a grip end and a shaft which is torsion-proof with respect to the grip end. The housing further ideally comprises guide means especially for this embodiment in the manner that the rotary lever is securely mounted in the housing on the one hand and enables a rotational movement for actuating the engine stop switch and the tank shut-off valve on the other hand. It is appropriate that also the engine stop switch and/or the tank shut-off valve are housed in the housing and/or are fastened or mounted in the housing in order to ideally obtain a compact and connected mounting unit.
In order to facilitate the operation of the actuating device by the operator, the limitation of the rotational movement of the rotary lever of the second actuating means by a limitation device, especially a limit stop, has proven to be advantageous in a rotational bearing of the rotary lever, especially the housing. The limitation device is effective in at least one actuation direction of the rotary lever and thereby predetermines a maximum actuation path for the movable actuating means. A maximum actuating path can therefore not be exceeded. It is thus ensured that the operator is unable to overtwist the rotary lever and thereby damage parts of the linkage to the engine stop switch and/or the tank shut-off valve. It is therefore optimal, in one embodiment, when the actuating movement is delimited in both actuating directions, i.e., when using a rotary lever in both rotational directions, respectively by a limitation device, especially a limit stop. For this purpose, the limitation device can be formed by one or even two mechanical motion stops. Such a mechanical motion stop is arranged in an especially preferred manner as a soft limit stop, which can be effected by an elastic tongue arranged on the housing, against which the movable actuating means will impinge in a soft fashion upon reaching its final movement position, for which purpose a contact element is provided on the movable actuating means which corresponds with the tongue. The tongue and the contact element can also be arranged in an exchanged manner.
As an alternative or in addition to a limit stop, a latching or locking device can be provided for latching or locking the rotary lever in at least one defined position. The difference between the latching or locking device and the limit stop is that it does not necessarily represent an actuating path limitation. The rotary lever can respectively also be moved beyond the latching or locking position. The latching or locking device ensures that the second actuating means will assume a specific defined actuating position which can be perceived by the operator. It is thereby ensured that the operator will reach the joint switching point of the engine stop switch and the tank shut-off valve, depending on the position of the latching or locking device for opening the tank shut-off valve and for releasing the ignition contact by the engine stop switch or for closing the tank shut-off valve and for interrupting the ignition contact by actuating the engine stop switch. The latching device is characterized in that it is arranged in a manner for ensuring a switching process that it will conceivably latch before and/or after the switching point (i.e., after reaching the switching point). The relevant aspect of the locking device is that it comprises means which enable fixing the second actuating device in a position before and/or after the switching point. Both embodiments come with the advantage that the switching position of the second actuating means is additionally secured, which is especially advantageous during transport when the actuation of the engine stop switch (for interrupting the ignition contact) and the positioning of the tank shut-off valve in a position interrupting the fuel supply are to be ensured. Securing the second actuating means can also additionally or alternatively be provided for the operating state in order to fix the tank shut-off valve in an opened position and the engine stop switch in a position that does not interrupt the ignition circuit. This is especially advantageous with respect to the considerable vibrations occurring in the operation of the soil compaction apparatus. The locking or latching device preferably acts between the housing and a part of the rotary lever, especially by corresponding locking or latching elements.
Although a broad spectrum of various embodiments can be used for implementing the present invention, an integral arrangement of the rotary lever, i.e., the shaft and the grip end, have proven to be ideal especially in one embodiment in order to simplify production and maintenance. Further, especially in the case of an integral arrangement of the rotary lever, plastic material is preferably used, especially a cold-resistant and impact-proof plastic material, especially from the group of the thermoplastic materials. The latter especially allows production by way of an injection-molding process, by means of which the production process can be further optimized. Reinforcing materials can principally also be incorporated in the plastic material.
The engine stop switch is frequently a contact or pressure switch. Although such switches are relatively robust, excessive pressing in should principally also be avoided in these switches in order to permanently ensure reliable functioning. Excessive pressing can for example damage the restoring mechanism of the engine stop switch which is frequently arranged in form of a restoring spring. The present invention provides, in one embodiment, the presence of an elastic loading protection for this purpose, which is arranged in the manner that a maximum actuating path of the engine stop switch is not exceeded in at least one actuating direction. The loading protection can especially be arranged in the manner that the engine stop switch will yield upon exceeding a maximum actuation of the actuating force, e.g., transmitted by a control surface which is in contact with the engine stop switch. The bearing of the engine stop switch can specifically be provided in a protruding bearing tongue, with the bearing tongue preferably being connected only on one side with a bearing body, especially a part of the housing. The bearing tongue is provided with a certain amount of elasticity, especially when it is made of plastic. An integral arrangement of the bearing tongue with a relevant part of the housing is ideal, e.g., one half of the housing. If the actuating force acting on the contact switch therefore exceeds a maximum value, the contact switch yields by bending of the bearing tongue, as a result of which overload protection for the contact switch is achieved.
A soil compaction device incorporating at least one actuating device in accordance with the present invention may comprise a hand-operated soil compaction device, especially a vibration tamper or a vibrating plate. The actuating device is preferably fixed to a fuel tank of the soil compaction device or integrated in a housing of the fuel tank.
The present invention will be described below in a non-limiting way by reference to the embodiment shown in the drawings, which schematically show as follows:
a and 5b show a schematic comparison of the switching processes under actuation of the rotary switch in the direction of “engine stop” and in the direction of “ready for operation”, and
Reference numeral 70 relates to an engine stop switch which is arranged in the housing 81 of the second actuating means or element 80 and which is similarly actuated in a virtually simultaneous manner with an actuation of the tank shut-off valve when the shaft 82 is twisted, as will be described below in greater detail in connection with
In the illustration as shown in
The control angle for the shaft 82 which lies between the rotational position as shown in
A rotatable shaft 82 is provided in the illustrated embodiment as an actuating means for the joint actuation of the tank shut-off valve 60 and the engine stop switch 70. A longitudinally displaceable slide and/or an electric switch could be provided in an analogous manner as an actuating means, with which both the tank shut-off valve 60 and the engine stop switch 70 can be actuated. A relevant aspect is that the tank shut-off valve 60 and the engine stop switch 70 are actuated simultaneously in one embodiment. This is further shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2011 100 155.0 | May 2011 | DE | national |
