Patent Publication Number: US-9428960-B2

Title: Drilling unit

Description:
FIELD OF THE INVENTION 
     The invention relates to a drilling unit, in particular for creating boreholes in the ground, according to the preamble of claim  1 . 
     Such a drilling unit comprises a carrier vehicle with a hydraulic supply, a mast, a carriage which can be moved along the mast and a hydraulic cylinder for moving the carriage which comprises a cylinder housing, in which a piston with a piston rod is mounted so that it can be displaced. 
     DESCRIPTION OF RELATED ART 
     It is usual with hydraulic cylinders to arrange the cylinder housing on the stationary side and the piston rod on the movable side as the hydraulic connection of a hydraulic cylinder is on the cylinder housing and as far as possible is not to be moved. A simple and maintenance-friendly connection of the hydraulic cylinder to a hydraulic supply is thus guaranteed. 
     In order to move a drilling carriage along the mast of a drilling unit it is thus known to fix the cylinder housing to the mast which constitutes a stationary base as opposed to the carriage which is mounted so that it can be moved thereon. Accordingly the piston rod of the hydraulic cylinder is fixed to the carriage in known drilling units. 
     SUMMARY OF THE INVENTION 
     It is the object of the invention to indicate a drilling unit with a constructively simple carriage drive which can be operated particularly economically. 
     The object is achieved according to the invention through a drilling unit with the features of claim  1 . Preferred embodiments of the invention are indicated in the dependent claims. 
     The drilling unit according to the invention is characterised in that the piston rod is fixed to the mast and the cylinder housing to the carriage, the carriage is connected to the hydraulic supply and comprises at least one hydraulic connection and the hydraulic cylinder is connected via the hydraulic connection on the carriage to the hydraulic supply. 
     According to a first basic idea of the invention the hydraulic cylinder is incorporated in such a way that the cylinder housing is arranged on the carriage and thus moves together with the carriage in relation to the mast. If the mast is upright the hydraulic cylinder is usually arranged above the carriage in order to push the carriage downwards in drilling operation. Therefore, the centre of gravity of the drilling unit is moved downwards through the cylinder housing arranged below. Indeed the cylinder housing usually has a greater weight than the piston with the piston rod mounted therein. The incorporation direction of the hydraulic cylinder according to the invention thus leads to improved stability of the drilling unit. 
     A second basic idea of the invention can be seen in that the hydraulic cylinder is connected via the carriage to the central hydraulic supply of the drilling unit, said hydraulic supply usually being arranged on the carrier vehicle. The supply of the hydraulic cylinder with hydraulic fluid, in particular hydraulic oil, has the advantage that no relative movements take place between the cylinder housing and the carriage. A simple laying of a line between the carriage and one or optionally more inlet nozzles on the cylinder housing is thus possible. 
     According to the invention at least one hydraulic connection is present on the carriage, via which hydraulic fluid can be fed to the hydraulic cylinder. The hydraulic connection is for its part connected to a central hydraulic supply. The hydraulic connection which can for example comprise a coupling means for coupling a hydraulic line is fixedly arranged on the carriage and moves together with it. The hydraulic connection can for example be arranged on a retaining means fixed to the carriage such as a retaining plate. 
     According to a preferred embodiment of the invention at least one distribution means is provided for distributing hydraulic fluid. The distribution means is preferably connected via a central supply line and a central return line to the hydraulic supply. Through the distribution means the hydraulic fluid supplied by the central hydraulic supply can be distributed to a plurality of consumers. In addition hydraulic fluid travelling back can be collected at the distribution means and fed to the central return line. The central distribution means thus allows a plurality of consumers to be supplied with hydraulic fluid in the region of the carriage. 
     In order to supply further consumers, in particular a drive motor on the carriage, it is preferred for the distribution means to comprise one or further hydraulic connections. The drive motor on the carriage can for example be a hydraulic rotary drive for a drill rod assembly or also a hydraulic vibrator drive. By means of the distribution means therefore both the hydraulic cylinder and the drive motor on the carriage can be supplied with hydraulic fluid from the central hydraulic supply. 
     The distribution means for distributing hydraulic fluid to the hydraulic cylinder and one or more further consumers is preferably fixedly arranged on the carriage and moves together with it. The hydraulic connection for the hydraulic cylinder and the at least one further hydraulic connection are preferably arranged on the distribution means. Through the distribution means hydraulic fluid is thus preferably distributed to a plurality of hydraulic connections. 
     Alternatively or additionally it is possible for at least one distribution means to be arranged on the mast. The distribution means on the mast allows a simple laying of a line between the central hydraulic supply and the distribution means, as the position of the distribution means on the mast is independent of a carriage movement along the mast. The distribution means is preferably fixedly arranged on the mast. 
     In principle the hydraulic cylinder for moving the carriage can be a single acting cylinder, wherein the cylinder housing is moved relative to the piston rod by supplying hydraulic fluid and moves the carriage in the direction of the borehole to be created, preferably downwards. For particularly efficient production of a borehole, however, it is preferable for the hydraulic cylinder to be a double acting cylinder with two cylinder chambers and for two hydraulic connections to be provided on the carriage, wherein a first cylinder chamber of the hydraulic cylinder is line-connected to a first hydraulic connection and a second cylinder chamber is line-connected to a second hydraulic connection. For example the first hydraulic connection can be connected to a lower cylinder chamber of the hydraulic cylinder and the second hydraulic connection to an upper cylinder chamber of the hydraulic cylinder. Through the supply of hydraulic fluid to the first hydraulic connection the cylinder housing can be moved out relative to the piston and correspondingly moved in through the supply of hydraulic fluid to the second hydraulic connection. 
     An advantageous supply of the hydraulic cylinder with hydraulic fluid is achieved in that at least one hydraulic line is arranged between the hydraulic connection and the hydraulic cylinder, said hydraulic line extending from the hydraulic connection upwards along the mast. The supply of the hydraulic cylinder with hydraulic fluid thus takes place on an extensively direct path from the carriage to the corresponding connection nozzle on the cylinder housing. The whole line can preferably be moved between the hydraulic connection on the carriage and connection nozzle on the hydraulic cylinder relative to the mast. A supply via the mast requiring comparatively high resources is not therefore necessary. 
     A particularly robust carriage drive can be achieved in that a fixed pipeline is provided between the hydraulic connection on the carriage and the hydraulic cylinder. A fixed pipeline is hereby to be understood to be in particular an extensively dimensionally stable or rigid line. The line can be made of metal for example but also from a correspondingly solid plastic. The line between the hydraulic connection and the connection nozzle is preferably fixed to the cylinder housing with at least one fixing means. 
     An advantageous connection of the hydraulic cylinder to the second hydraulic supply can be achieved in that at least one central supply line is arranged between the hydraulic connection and the hydraulic supply, said central supply line being fixed to a retaining element on the mast. As the mast itself usually only moves very slightly during drilling operation relative to the carrier vehicle, in particular the upper structure, secure laying of a line can take place through the retaining element fixed to the mast. A flexible line is thus necessary essentially merely in a section between the retaining element on the mast and the hydraulic connection provided on the carriage. 
     The flexible line section between the retaining element and hydraulic connection can thereby be kept particularly short in that the retaining element is arranged centrally on the mast having regard to the cylinder housing of the hydraulic cylinder. A flexible line section can also extend between the mast and carrier vehicle. The retaining element is arranged in particular half way along the movement path of the carriage along the mast. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described further below by reference to a preferred embodiment which is schematically shown in the attached drawing, in which: 
         FIG. 1  shows an inventive drilling unit; 
         FIG. 2  a lower section of the mast of the drilling unit of  FIG. 1 ; and 
         FIG. 3  an enlarged view of  FIG. 2 . 
     
    
    
     Corresponding components are identified in all the drawings with the same reference numerals. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  shows an inventive drilling unit  10  with a mast  16  which is in a folded down, approximately horizontal transport position. The drilling unit  10  comprises a carrier vehicle  12  with an undercarriage  13  and an upper structure  14  which is rotationally mounted on the undercarriage  13 . The undercarriage  13  can comprise a chassis, in particular a crawler chassis. 
     The mast  16  is pivotally mounted via a pivot joint  20  on the carrier vehicle  12 , in particular on the upper structure  14 , and can be pivoted between an approximately horizontal transport position and an approximately vertical operating position. 
     In order to erect or lower the mast  16  one or more erection cylinders  26  are provided which are fixed on the one hand on the mast  16  and on the other hand on a corresponding connection point on the carrier vehicle  12 . The erection cylinder  26  can also be described as a stick cylinder. 
     On a front side  17  of the mast  16  which forms a lower side in the transport position a carriage  22  is mounted so that it can be displaced longitudinally along a guide means  18 . The guide means  18  can in particular comprise a guide rail which is in engagement with guide shoes of the carriage  22 . 
     In order to move the carriage  22  along the mast  16  a carriage drive  28  is provided which comprises a hydraulic cylinder  30  with a cylinder housing  32  and a piston  34  mounted so that it can be displaced therein. The piston  34  is fixed to a piston rod  36 , of which the longitudinal axis extends coaxially with the longitudinal axis of the cylinder housing  32 . 
     The piston rod  34  is fixed at an upper connection point  40  on the mast  16 . The connection point  40  comprises a pivot joint with a pivot bolt which is mounted on a bearing plate  42  of the mast  16 . The cylinder housing  32  is fixed at a lower connection point  38  on the carriage  22 . The connection point  38  also comprises a pivot joint with a pivot bolt. 
     Through the cylinder housing  32  arranged in the lower region of the mast  16  and the piston rod  36  arranged in the upper region of the mast  16  the centre of gravity of the mast  16  is moved downwards so that simpler erection and lowering of the mast can take place by means of the erection cylinder  26 . 
     In order to actuate the hydraulic cylinder  30  the latter is connected to a central hydraulic supply  80 . The connection to the central hydraulic supply  80  thereby takes place via a hydraulic connection  50  which is fixedly arranged on the carriage  22  and can be moved with said carriage  22  relative to the mast  22 . For this purpose a retaining element  58  or retaining plate is fixed to the side on the carriage  22  and carries the hydraulic connection  50 . 
     The hydraulic cylinder  30  comprises a first, lower connection nozzle  44  which is connected via a first hydraulic line  62  to the hydraulic connection  50 . The hydraulic cylinder  30  further comprises a second, upper connection nozzle  46  which is connected via a second hydraulic line  64  to a second hydraulic connection  52  on the carriage  22 . The first connection nozzle  44  is line-connected to a first cylinder chamber of the hydraulic cylinder  30  and the second connection nozzle  46  to a second cylinder chamber of the hydraulic cylinder  30 . 
     Furthermore there is at least one further hydraulic connection  54  for a hydraulic motor, for example a rotary drive for a drill rod assembly, on the carriage  22 , in particular on the retaining means  58 . Both the hydraulic connections  50 ,  52  for the hydraulic cylinder  30  and also the further hydraulic connection  54  are connected to the central hydraulic supply  80 . 
     The hydraulic connections  50 ,  52 ,  54  are arranged on a distribution means  60  which distributes hydraulic fluid from the central hydraulic supply  80  to the hydraulic connections  50 ,  52 ,  54 . Furthermore there is a return connection  56  on the distribution means  60  for returning hydraulic fluid. The distribution means  60  is fixed to the carriage  22  and can also include the retaining means  58 . 
     A retaining element  70  is fixed to the mast  16  approximately half way along the movement path of the carriage  22 , whereby a central supply line  82  and a central return line  84  are connected to said retaining element  70 . The retaining element  70  can comprise a further distribution means  72 , as shown schematically in  FIGS. 2 and 3 . In particular it can be provided that a distribution means  72  is provided on the mast  16  for distribution of hydraulic fluid between the upper and the lower cylinder chamber of the hydraulic cylinder  30 . The corresponding distribution can, however, also take place on the distribution means  60  on the carriage  22 . The hydraulic cylinder  30  is thus connected to the central hydraulic supply  80  via a first retaining element  58  fixedly arranged on the carriage  22  and a second retaining means  70  fixedly arranged on the mast  60 . Both retaining elements  58 ,  70  can also be formed as distribution means  60  and  72  respectively. 
     One or more flexible tube sections  74  for feeding and/or returning hydraulic fluid are provided between the retaining element  70  and the carriage  22 , in particular the hydraulic connection  50  and the distribution means  60  respectively. In the embodiment shown according to  FIGS. 2 and 3  the flexible tube sections comprise a section of a hydraulic line to the lower cylinder chamber of the hydraulic cylinder  30 , a section of a hydraulic line to the upper cylinder chamber of the hydraulic cylinder  30  and a section of a return line. Furthermore line sections can be provided to the at least one further hydraulic connection  54  on the distribution means  60  which are not shown in the drawings. The flexible tube section  74  can also be a part of the central supply line  82  and/or the central return line  84 . 
     All in all a drilling unit is provided according to the invention with a constructively simple carriage drive which additionally facilitates economical erection and lowering of the mast relative to the carrier vehicle.