Patent Publication Number: US-2013233624-A1

Title: Drilling apparatus having head

Description:
TECHNICAL FIELD 
     The present invention relates to a drilling apparatus, and more particularly, to a drilling apparatus having a head, which facilitates engagement or disengagement between a rod and a driving shaft installed in the head when a drilling work is performed using a bit. 
     BACKGROUND ART 
     In general, a drilling apparatus is used to excavate deep holes into the ground for purposes of boring, soil testing or development of underground water. The drilling apparatus is classified into a type in which a boring work is performed while rotating a rod having a bit, and a type in which a boring work is performed by rotating a rod having a bit or a cutter and striking the bit or the cutter using the rod. 
     A conventional drilling apparatus is disclosed in Korean Patent No. 624233. The disclosed drilling apparatus comprises a main body having a driving device such as an engine, a leader supported by the main body, and a head sliding along the leader and generating an elevational force or a rotational force by a driving device provided in the main body, a rod coupled to the head and elevating or rotating by the head, and a drill unit provided at a front end of the rod and perforate the ground while elevating or rotating along with the rod. 
     The drill unit includes a bit striking and drilling the ground and a hammer operated by a hydraulic pressure to apply a striking force to the beat. The drilling apparatus is configured to drill the ground to a predetermined depth such that the bit of the drill unit rotates or strikes the ground. 
     As the excavated depth increases in the course of drilling, the drilling work is performed by connecting unit rods to allow a drill unit to excavate the ground deeper and deeper. The unit rods are connected such that a driving shaft of a head is separated from the unit rod currently performing the drilling work and then connected to a new unit rod to perform a drilling work. 
     In the course of drilling, if the unit rods have relatively small diameters, it is difficult to align the driving shaft of the head with the unit rod. In particular, even if the unit rod and the driving shaft are coaxially aligned, it is not easy to screw-couple the unit rod to the driving shaft. Thus, it is impossible to increase the efficiency of the drilling work due to a trouble in screw-coupling of the unit rod and the driving shaft. 
     Meanwhile, a support pipe is installed to prevent a landslide during the drilling work. As the drill unit and the unit rod are inserted into the ground to a gradually increasing depth, it is necessary to connect the support pipe. Since there is no separate means for balancing the support pipe, the support pipe may vibrate or may not be aligned with the center of a rotation shaft. Therefore, it is necessary to adjust the support pipe installed on the ground when the support pipe is connected. 
     DISCLOSURE OF THE INVENTION 
     In order to overcome the above-mentioned shortcomings, the present invention provides a drilling apparatus having a head, which facilitates engagement or disengagement between a rod and a driving shaft of the head when a drilling work is performed, thereby increasing the efficiency in the drilling work. 
     The present invention also provides a drilling apparatus having a head, which enables engagement between a driving shaft and a unit rod according to the diameter of the unit rod connected to the driving shaft. 
     According to an aspect of the invention, there is provided a drilling apparatus having a head, including a main body, a lead supported by the main body of the drilling apparatus, a driving shaft slidably installed in the lead and having a unit rod connected thereto for performing drilling work, and a head having an actuator for driving the driving shaft, wherein the driving shaft includes a screw coupling part formed on the outer circumferential surface of the driving shaft and screw-coupled with an end of the unit rod for performing the drilling work, and a screw coupling inducing part formed at a front end of the screw coupling part to induce screw coupling between the driving shaft and a rod screw coupling part formed at a hollow part formed at the end of the unit rod. 
     A stopper may be provided on the outer circumferential surface of a top end of the screw coupling part of the driving shaft for preventing the unit rod screw-coupled to the driving shaft from elevating. 
     The screw coupling induction part may include a taper part extending from the screw coupling part of the driving shaft to an end of the screw coupling induction part and having diameters gradually decreasing. 
     According to another aspect of the invention, there is provided a drilling apparatus having a head, including a main body, a lead supported by the main body of the drilling apparatus, a driving shaft slidably installed in the lead and having a unit rod connected thereto for performing drilling work, and a head having an actuator for driving the driving shaft, wherein the driving shaft includes a first driving shaft supported on the head body by a bearing and exposed to a bottom end of the head body, and a second driving shaft having a screw coupling part screw-coupled coaxially with the first driving shaft and screw-coupled with an end of the unit rod for performing the drilling work, and a screw coupling inducing part formed at a front end of the screw coupling part to induce screw coupling between the driving shaft and a rod screw coupling part formed at a hollow part formed at the end of the unit rod. 
     The first driving shaft may include stepped coupling parts having different diameters, and a plurality of second driving shafts having different diameters to be selectively coupled to the coupling parts of the first driving shaft. 
     As described above, in the drilling apparatus having a head according to the present invention, the unit rod and the driving shaft can be easily engaged with each other during a drilling work, thereby increasing the efficiency of the drilling work. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects, features and advantages of the present invention will be more apparent from the following detailed description in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a side view of a drilling apparatus having a head according to the present invention; 
         FIG. 2  is a cross-sectional view of the drilling apparatus shown in  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of a driving shaft according to an embodiment of the present invention; 
         FIGS. 4 and 5  are perspective views of driving shafts according to another embodiment of the present invention; and 
         FIG. 6  is a perspective view illustrating a state in which a driving shaft and a unit rod are engaged with each other. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
     The drilling apparatus according to the present invention facilitates engagement between a unit rod and a driving shaft of the head when the ground hole is excavated, and en exemplary embodiment of the drilling apparatus is shown in  FIGS. 1 to 5 . 
     Referring to  FIGS. 1 to 5 , the drilling apparatus  100  having a head includes a lead  20  supported by a main body  10 , a driving shaft  40  slidably installed in the lead  20  and connected to the topmost unit rod among the unit rods  70  connected to each other for drilling work, a head  30  having an actuator (not shown) for driving the driving shaft  40 , and a support pipe  200  installed on the ground for preventing earth and sand around a hole excavated by the lead from collapsing. 
     The head  30  slidably installed along the lead  20  and is configured to elevate by a separate driver (although not shown, the driver including sprockets installed at top and bottom portions of the lead  20 , a chain locked on the sprockets and having one side fixed to the head  30 , and a hydraulic motor driving one of the sprockets). As shown in  FIG. 2 , a hydraulic motor  33  for driving the driving shaft  40  rotatably supported by the bearing  32  is installed in a main body  31  of the head  30 . The hydraulic motor  33  receives hydraulic oil by a hydraulic supply system installed in the main body  10  to then be driven. 
     As shown in  FIGS. 2 and 3 , the driving shaft  40  includes a screw coupling part  41  and a screw coupling inducing part  42 . The screw coupling part  41  is formed on the outer circumferential surface of the driving shaft  40  and is screw-coupled to an end of the unit rod  70  for performing a drilling work. The screw coupling inducing part  42  is formed at a front end of the screw coupling part  41  to smoothly achieve screw coupling between the driving shaft  40  and a rod screw coupling part  73  formed at a hollow part  70   a  at the end of the unit rod  70 . A stopper  43  is formed on the outer circumferential surface of the driving shaft  40  at a top end of the driving shaft  40 , corresponding to a terminating end of the screw coupling part  41 , to prevent the unit rod  70  screw-coupled to the screw coupling part  41  from being damaged while rotating. 
     The stopper  43  may include a protrusion formed on the outer circumferential surface of the driving shaft  40 , but aspects of the present invention are not limited thereto. 
     The hollow part  40   a  is formed at the driving shaft  40  in a lengthwise direction. The screw coupling inducing part  42  may be tapered upwardly from its end. That is to say, a diameter of an end of the screw coupling induction part  42  is smaller than that of the driving shaft  40 . Smooth surfaces  45  and  46  symmetrical about the center of the driving shaft  40  are provided at one or more sides of the screw coupling part  41  or the screw coupling inducing part  42 . When the driving shaft  40  includes first and second driving shafts to be described later, the smooth surfaces  45  and  46  are provided for engagement or disengagement of the first driving shaft and the second driving shaft. 
       FIG. 4  illustrates a head driving shaft of a drilling apparatus according to another embodiment of the present invention. 
     Referring to  FIG. 4 , a head driving shaft  50  is supported on the head body  31  by a bearing  32  to be rotatably installed, and includes a first driving shaft  51  formed at an end exposed to a bottom end of the head body  31  and a second driving shaft  55  combined with the first driving shaft  51 . 
     The first driving shaft  51  may include stepped coupling parts  51   a ,  51   b  and  51   c  having different diameters. Screws for being coupled to the second driving shaft  55  are formed on the outer circumferential surfaces of the coupling parts  51   a ,  51   b  and  51   c.    
     The second driving shaft  55  may include a plurality of second driving shafts having different diameters (corresponding to diameters of unit rods) to be engaged with the coupling parts  51   a ,  51   b  and  51   c  of the first driving shaft  51 . The second driving shafts  55  having different diameters are provided for the purpose of being compatibly used when the unit rods for performing a drilling work have different diameters. 
     The second driving shaft  55  may include a coupling screw part  56 , a screw coupling part  57  and a screw coupling inducing part  58 . The coupling screw part  56  is formed on the inner circumferential surface of the second driving shaft  55  to be coaxially coupled to the first driving shaft  51 , the screw coupling part  57  is formed on the outer circumferential surface of the second driving shaft  55  to be screw-coupled to the rod screw coupling part  73  of the unit rod  70 , and the screw coupling inducing part  58  extends from the screw coupling part  57 . As described above, the screw coupling inducing part  58  is tapered such that its diameter gradually decreases from the screw coupling part  57  to its end. The end of the screw coupling induction part  58  may be spherical to facilitate insertion of the hollow part  70   a  of the unit rod  70  into the screw coupling induction part  58 . A hollow part  40   a  is formed in a lengthwise direction of the first and second driving shafts  51  and  55 . 
     As shown in  FIG. 5 , the first and second driving shafts  51  and  55  may be coupled to the first and second driving shafts  51  and  55  by flange parts  61  and  62 . 
     A stopper  59  may be installed in the second driving shaft  55  to prevent the unit rod  70  coupled to the second driving shaft  55  and performing a drilling work from elevating while rotating. A position adjusting unit (not shown) may further be provided at an upper portion of the stopper  59  to hold the support pipe  200  inserted into an excavated portion for preventing earth and sand existing around the excavated portion from collapsing. The position adjusting unit is tapered such that its upper side has a larger diameter than the support pipe  200 . 
     The aforementioned drilling apparatus operates as follows. 
     As shown in  FIGS. 1 and 6 , in order to excavate an underground hole using the drilling apparatus according to the present invention, the drilling apparatus is positioned at a portion where the ground hole is to be formed, and the lead  20  is vertically positioned on the portion where the ground hole is to be formed. In such a state, the head  30  is positioned on the lead  20  and the unit rod  70  is then connected to the driving shaft  40 . An air hammer or a water hammer  80  for performing a drilling work is installed at a bottom end of the unit rod  70 . 
     The unit rod  70  and the driving shaft  40  are engaged with each other such that the unit rod  70  is suspended using a crane (not shown), the screw coupling induction part  42  of the driving shaft  40  is inserted into the hollow part  70   a  of the unit rod  70 , and the driving shaft  40  is rotated while moving the unit rod  70  and the driving shaft  40  with respect to each other. In such a manner, in a state in which the screw coupling induction part  42  extending from the screw coupling part  41  of the driving shaft  40  is inserted into the hollow part  70   a  of the unit rod  70 , the screw coupling part  41  is guided to the rod screw coupling part  73  of the unit rod  70 , thereby facilitating engagement of the unit rod  70  and the driving shaft  40 , which will now be described in more detail. Since the screw coupling induction part  42  provided at the driving shaft  40  has a diameter gradually decreasing from the screw coupling part  41 , even if the unit rod  70  and the driving shaft  40  are not aligned in line, the screw coupling induction part  42  can be easily inserted into the hollow part  70   a  of the unit rod  70 . 
     Therefore, the problem associated with the conventional drilling apparatus, that is, the necessity for making the end of the unit rod  70  and the driving shaft  40  coincide with each other by an operator&#39;s manual work, can be solved. In particular, when the unit rod  70  has a small diameter and a small thickness, engagement of the unit rod  70  and the driving shaft  40  can be smoothly achieved by being guided by the screw coupling induction part  42 . 
     The above-described operation is achieved in the same manner as in engagement of the second driving shafts  55  and the unit rod  70 . In particular, as shown in  FIG. 4 , the coupling parts  51   a ,  51   b  and  51   c  formed in multiple-steps are provided in the first driving shaft  51 , and the second driving shafts  55  suited to diameters of the respective coupling parts  51   a ,  51   b  and  51   c  are provided, thereby allowing the second driving shafts  55  to be compatibly used according to the diameters of the unit rods for performing a drilling work. 
     Meanwhile, the stopper  43  for preventing the unit rod  70  from elevating due to a rotational force of the driving shaft  40  when the unit rod  70  is screw-coupled is provided at the driving shaft  40 . Thus, even if a rotational load is applied to the unit rod  70  during a drilling work, it is possible to prevent the unit rod  70  from elevating along the screw coupling part  41  of the driving shaft  40 . It is also possible to prevent the unit rod  70  screw-coupled to the screw coupling part  41  from being damaged due to the rotational load applied thereto while rotating. That is to say, the unit rod  70  can be prevented from being damaged, which may be caused when the unit rod  70  elevates to a portion of the driving shaft  40  without screws due to the rotational load. 
     In addition, the position adjusting unit for balancing the support pipe  200  installed for drilling soft ground is further provided at the driving shaft  40 . When the head  30  is lowered, the position adjusting unit is inserted into the support pipe  200 , thereby aligning centers of the support pipe  200  and the driving shaft  40 . Therefore, it is possible to prevent the center of the support pipe  2000  from deviating from the center of the unit rod  70  while the drilling work is performed. 
     Although exemplary embodiments of the present invention have been described in detail hereinabove, it should be understood that many variations and modifications of the basic inventive concept herein described, which may appear to those skilled in the art, will still fall within the spirit and scope of the exemplary embodiments of the present invention as defined by the appended claims.