Abstract:
An apparatus for pile-driving or drilling, particularly a foundation machine, including at least one hydraulic drilling or vibration drive, which is connected with a control block in an open hydraulic circuit, by way of which drive at least one further consumer can be operated. The drive is connected with a pump by way of a first feed line and with a tank by way of a first return line. The hydraulic drive is additionally connected directly with the pump by way of a second feed line, and directly with the tank by way of a second return line.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    Applicant claims priority under 35 U.S.C. §119 of European Application No. 14163092.1 filed Apr. 1, 2014, the disclosure of which is incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to an apparatus for pile-driving or drilling, particularly a foundation machine. 
         [0004]    2. Description of the Related Art 
         [0005]    Leader-guided vibration pile drivers as well as drilling devices and foundation machines in general are regularly operated hydraulically. In this connection, an open hydraulic circuit is used, because in this way, in contrast to a closed circuit, the operation of different work devices, such as, for example, vibrators, drilling drives, presses, etc., as well as a switch between different consumers such as a work device or a drive of a crawler track drive is made possible. The open hydraulic circuit has a control block or valve block, from which different consumers can be controlled. 
         [0006]    The previously known solutions have the disadvantage that the control block represents a hydraulic resistance for the oil volume stream. For this reason the control block brings about a reduction in the power to be transferred. A reduction of this power loss can be achieved by means of using a larger block having a larger cross-section, but this larger block requires a lot of construction space and is furthermore very expensive. 
         [0007]    The lost power of the control block is caused by the flow valves used in the control block. Flow valves correspond to throttle valves in terms of their construction, and allow control of the hydraulic volume stream by way of a changeable pressure loss. The valves of the control block are controlled directly by the operator, by way of a manual controller, for example by means of a joystick (hydraulic pre-controller), or also by way of auxiliary valves, also called pre-control valves, which in turn are activated electrically by the operator. If only one consumer is being operated, for example a vibration pile-driver during pile-driving operation, when a vibrator uses the full power as the sole consumer, the control block does not have any function; it merely serves to pass the oil volume stream through, but does hinder the passage of the oil volume stream as a consequence of the design-related flow resistance. 
       SUMMARY OF THE INVENTION 
       [0008]    The invention wishes to provide a remedy for this situation. The invention is based on the task of making available an apparatus for pile-driving or drilling, particularly a foundation machine having a hydraulic drilling or vibration drive, in which the hydraulic power lost as the result of the flow resistance in the control block is reduced. According to the invention, this task is accomplished by means of an apparatus for pile-driving or drilling, particularly a foundation machine, including at least one hydraulic drilling or vibration drive, which is connected with a control block in an open hydraulic circuit. By way of the drive at least one further consumer can be operated. The drive is connected with a pump by way of a first feed line and with a tank by way of a first return line. The hydraulic drive is additionally connected directly with the pump by way of a second feed line, and directly with the tank by way of a second return line. 
         [0009]    With the invention, an apparatus for pile-driving or drilling, particularly a foundation machine having a hydraulic drilling or vibration drive, is created, in which the hydraulic power lost as the result of the flow resistance in the control block is reduced. Because the drive is additionally connected directly with the pump, by way of a second feed line, and directly with the tank, by way of a second return line, the control block is disposed hydraulically parallel to the actual working lines that lead directly from the pump to the work device as the main consumer and from the work device to the tank. The control block is therefore switched as a bypass for the direct connections between pump and working device and between working device and tank. In this way, direct application of hydraulic oil to the work device is made possible. 
         [0010]    In a further development of the invention, a valve, preferably a directional valve for blocking the line, is disposed, in each instance, in the second feed line as well as in the second return line, in such a manner that in the blocked state of the second feed line and of the second return line, the control block functions as the only connection between pump and drive. Consequently, unrestricted supply to the consumers connected with the control block is guaranteed. The main volume stream flows through the control block, as described in the state of the art. 
         [0011]    In a further development of the invention, a valve, preferably a directional valve, is disposed in the first feed line for blocking this line. As a result, after this valve is closed, no division of the volume stream in accordance with the hydraulic resistances both by way of the block and by way of the direct connection takes place. Because of the separation of the control block from the hydraulic circuit, a greater pressure can be permitted also in the case that the pressure in the hydraulic circuit is limited by the design-related permissible pressure in the control block. 
         [0012]    In a further embodiment of the invention, the drive is directly connected with the pump by way of a third return line. In this embodiment at least one valve, in each instance, preferably a directional valve, is provided for optional separation of the hydraulic drive with the tank and connection of the hydraulic drive and the pump, in such a manner that a closed circuit between pump and drive can be achieved. Via the valves provided, the suction line in the pump can be optionally connected with the tank or with the return line from the work device. In this way, priming losses of the pump can be avoided. 
         [0013]    Furthermore, the pump can be impacted with an elevated input pressure in this manner. Last but not least, greater efficiency can be achieved by means of a closed hydraulic circuit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Other objects and features of the invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention. 
           [0015]    In the drawings, wherein similar reference characters denote similar elements throughout the several views: 
           [0016]      FIG. 1  is a schematic representation of a vibration pile-driver disposed on a carrier device; 
           [0017]      FIG. 2  is a schematic representation of the vibrator drive of the vibration pile-driver from  FIG. 1 ; 
           [0018]      FIG. 3  is a representation of a hydraulic plan for supplying the hydraulic drives of the vibrator gear mechanism from  FIG. 2 ; 
           [0019]      FIG. 4  is a representation of the hydraulic plan from  FIG. 3  in another embodiment; 
           [0020]      FIG. 5  is a representation of the hydraulic plan from  FIG. 3  in a third embodiment; 
           [0021]      FIG. 6  is a representation of the hydraulic plan from  FIG. 3  in a fourth embodiment. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0022]    Referring now in detail to the drawings the apparatus according to the invention will be described using a vibration pile-driver, the essential components of which are shown in  FIG. 1 . A vibration generator (vibrator)  3  is disposed on a carrier device  1 , so as to be vertically displaceable by way of a leader  2 . The vibration generator  3  comprises a housing  31  ( FIG. 2 ) that is surrounded by a hood  30 . A clamping gripper  32  for holding material  4  to be pile-driven is disposed on the hood  30 . The hood  30  serves for guiding the vibration generator  3  and transfers the static force of the leader  2  to the vibration generator  3 . The vibration generator  3  generates a vibration, by way of rotating imbalances  3311 ,  3321 ,  3331 ,  3511 ,  3521 ,  3531 , which vibration is transferred to the material  4  to be pile-driven by way of the clamping gripper  32 . Control of the vibration pile-driver takes place by way of a controller apparatus  11  that is connected with different sensors  13  by way of lines  12 . 
         [0023]    The vibration generator  3  is structured as a vibrator gear mechanism ( FIG. 2 ). It consists essentially of a housing  31 , in which shafts  33 ,  35  provided with gear wheels  331 ,  332 ,  333 ,  351 ,  352 ,  353  are mounted so as to rotate. The gear wheels  331 ,  332 ,  333 ,  351 ,  352 ,  353  are provided with imbalance masses  3311 ,  3321 ,  3331 ,  3511 ,  3521 ,  3531 , in each instance, whereby the gear wheels of the two shafts  33 ,  35  are in engagement with one another by way of gear wheels  3613 ,  3614  of the rotor shaft  361  of a pivot motor  36  or with the gear wheel  3621  of the pivot motor  36 . The gear wheels  331 ,  332 ,  333 ,  351 ,  352 ,  353  provided with imbalance masses  3311 ,  3321 ,  3331 ,  3511 ,  3521 ,  3531  can be adjusted relative to one another, in terms of their rotational position, by way of the pivot motor  36 , thereby making it possible to adjust the resulting imbalance or the resulting static moment. The shafts  33 ,  35  of the vibration generator  3  are connected with hydraulic drives  37 , by way of which they can be driven. The hydraulic drives  37  are connected with a hydraulic circuit  5  shown, for example, in  FIGS. 3-6 , by way of which they are supplied with hydraulic oil. 
         [0024]    The hydraulic circuit  5  is shown in a first embodiment in  FIG. 3 . A control block  53  is disposed in the hydraulic circuit  5 , which block is connected with a pump  52  by way of a first supply line  61 , which pump in turn is connected with a tank  51  for the hydraulic oil by way of a supply line  60 . On the return side, the control block  53  is connected with the tank  51  by way of a first return line  65  that is passed by way of a cooler  54 . The hydraulic drive  37  is connected with the control block  53 , on the inflow side, by way of a drive feed line  63 , and, on the return flow side, by way of a drive return line  64 , by way of hydraulic connectors A, B. In the exemplary embodiment, two further connectors A, B, for further consumers are provided on the control block  53 . 
         [0025]    The drive feed line  63  is directly connected with the pump  52  by way of a second feed line  62 . Furthermore, the drive return line  64  is directly connected with the tank  51  by way of a second return line  66 , by way of the cooler  54 . A first directional valve  71  is disposed in the second feed line, and a second directional valve  72  is disposed in the second return line. Feed to the hydraulic drive  37  by way of the control block  53  takes place by means of blocking the directional valves  71 ,  72 ; further consumers can be supplied at further connectors A, B of this block. In the open state of the directional valves  71 ,  72 , the volume stream flows past the control block  53  without hindrance, whereby the entire volume stream divides in accordance with the hydraulic resistances and flows both by way of the control block  53  and directly to the hydraulic motor  37 . 
         [0026]    In the exemplary embodiment according to  FIG. 4 , a third directional valve  73  is disposed in the first feed or supply line  61 , ahead of the control block  53 . By means of this additional directional valve  73 , the control block  53  can be separated from the hydraulic circuit  5  on the primary side, so that the volume stream conveyed by the pump  52  flows entirely to the hydraulic drive  37 . Furthermore, an excess pressure line  68  is connected with the first feed line  61  as well as with the second feed line  62 , which line ends in the tank  51  and in which line an excess pressure valve  8  is disposed. 
         [0027]    In the exemplary embodiments according to  FIGS. 5 and 6 , the drive return line  64  is additionally connected with the supply line  60  of the pump  52  by way of a third return line  67 , so that a closed circuit is formed. A fourth directional valve  74  is disposed in the third return line  67 . A fifth directional valve  75  is disposed on the supply line  60  between the tank  51  and the connector of the third return line  67 . Furthermore, a sixth directional valve  76  is disposed in the drive return line  64  of the hydraulic drive  37 , between the second return line  66  and the third return line  67 . By means of this arrangement, the supply line  60  of the pump  52  is optionally connected with the tank  51  or with the drive return line  64 . In this way, priming losses of the pump  52  can be avoided, for example. Furthermore, in this manner the pump  52  can have increased input pressure applied to it. 
         [0028]    In the exemplary embodiment according to  FIG. 6 , the directional valves  74  and  76  were replaced with a seventh directional valve  77  configured as a multi-directional valve, by way of which the return line  67  is connected with the drive return line  64 . 
         [0029]    Because of the losses that occur in every hydraulic circuit, the hydraulic oil warms up and therefore must be cooled. Oil coolers are regularly permitted for low pressures up to approximately  20  bar. When the circuit is open (directional valves  75 ,  76  open, directional valve  74  closed), the hydraulic oil runs into the tank  51  essentially without pressure, which oil is passed, in usual manner, to the tank  51  by way of an oil cooler. When the circuit is closed (directional valve  74  open, directional valves  75 ,  76  closed), such cooling is not easily possible. In order to cool the hydraulic oil in a closed circuit, the leakage oil that occurs in any case is regularly cooled. If necessary, an additional amount of oil is dispensed and passed by way of a cooler. The cooled oil must be returned to the hydraulic circuit by way of a feed pump. (In  FIGS. 5 and 6 , the possibility of taking the hydraulic fluid out and feeding it back in, in order to cool it, is not shown.) 
         [0030]    Although only a few embodiments of the present invention have been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.