Abstract:
The present invention relates to a impact body for a hydraulic impact device and, more specifically, to a impact body for a hydraulic impact device which is capable of remarkably reducing production costs by inserting a cylinder liner having a flow path into an inner wall of a body, adjusting an impact interval and an impact strength according to the properties of a material to be crushed by adjusting an impact distance of a piston, minimizing the loss of a fluid in a pipe by forming a cylindrical flow path between the body and the cylinder liner, and remarkably improving performance by employing a circular valve to shorten the flow path whereby reduction of pressure is minimized.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a U.S. National Phase application of pending International Application No. PCT/KR2013/005484 filed on Jun. 21, 2013, and claims priority of Korean Patent Application No. 10-2012-0072428 filed on Jul. 3, 2012, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a hitting body for a hydraulic hitting device and, more specifically, to a hitting body for a hydraulic hitting device which is capable of remarkably reducing production costs by inserting a cylinder liner having a flow path into an inner wall of a body, adjusting a hitting interval and a hitting strength according to properties of a material to be crushed by adjusting a hitting distance of a piston, minimizing the loss of fluid in a duct by forming a cylindrical flow path between the body and the cylinder liner, and minimizing reduction of pressure by employing a circular valve to shorten the flow path, thereby remarkably improving performance. 
       BACKGROUND OF THE INVENTION 
       [0003]    In general, a hydraulic hitting device mounted to construction machines such as an excavator or a loader etc. serves to crush or punch a concrete or a rock. There are a hydraulic and a hydraulic rock drill and so on. 
         [0004]    The hydraulic hitting device includes a hitting body and a bit rotation mechanism (hereinafter, “operating unit”) formed at the lower end thereof and having a bit rotated by a chisel or a rotary motor. 
         [0005]    A piston is formed inside the hitting body of the hydraulic hitting device and serves to hit the end of the operating unit while being moved up and down by a hydraulic pressure. 
         [0006]      FIG. 4  is a sectional view illustrating a state of mounting an operating unit  40  on a hitting body of a hydraulic rock drill according to the present invention. As shown, a bit rotation mechanism  2  having a bit  3  is formed at the lower end of the hitting body  1 . 
         [0007]      FIG. 6  illustrates a hydraulic breaker of the conventional hydraulic hitting device. As shown, the fixture  30  is formed at the lower end of the hitting body  1  and the operating unit  40  is fixed to the fixture  30 . 
         [0008]    The hitting body  1  includes a body  100  and an upper body  20 . The piston  50  is formed at the inside of the body  10  and the upper body  20  is formed on the upper portion of the body  10 . 
         [0009]    A plurality of flow path grooves is formed at an inner wall of the body  10  and a plurality of flow path holes, which is in communication with the flow path grooves, is formed at the wall of the body  10 . 
         [0010]    The piston  50  of the hitting body  1  is moved up and down by means of the pressure difference between the upper and lower surfaces generated by the fluid flowing through the flow path grooves  11  and the flow path holes  12 . At this time, the upper end of the operating unit  40  is repeatedly hit by the lower end of the piston  50 . 
         [0011]    The prior art on the hydraulic hitting devices are disclosed in Korean patent Nos. 1996-0006735, 0456786, 0998261, and 0772301 and Korean patent publication No. 2011-0086289. 
       SUMMARY OF THE INVENTION 
       [0012]    However, the hitting body of the conventional hydraulic hitting device has the following problems. 
         [0013]    (1) Since the large body should be overall precisely machined so as to minimize the clearance between the outer periphery and the inner wall off the piston, it takes a lot of the production cost and a long production time. 
         [0014]    (2) Since the piston is shocked and reciprocated inside the body, it is accompanied by intense pressure and heat. Accordingly, since it is necessary to be manufactured by a special material and perform a special heat treatment, it takes a lot of the production cost and a long production time. 
         [0015]    (3) When the high pressure port and the low pressure port is in communication with the inside of the body, since the duct should be formed long, it increases the loss of fluid in the duct. 
         [0016]    (4) Since the valve is formed at the outside of the body, the pressure is reduced owing to the long flow path, thus the performance is bad. 
         [0017]    (5) Since the hitting distance of the piston cannot be easily adjusted, the hitting strength cannot be controlled according to the properties of the material to be crushed. 
         [0018]    In order to solve the above problems, there is provided a hitting body for a general hydraulic stroke device according to the present invention having a body, a piston formed at the inside of the body, and an upper body formed on the upper portion of the body including: a cylinder liner inserted into and formed at the inside of the body; at least one operating flow path hole and return flow path hole formed at a wall of the cylinder liner respectively; and a circular valve formed between the seal retainers, which are formed at the upper end thereof. 
         [0019]    According to the hitting body for the hydraulic hitting device of the present invention has the following effects. 
         [0020]    (1) The production costs and time can be reduced since only the cylinder liner inserted into the body requires to be machined precisely. 
         [0021]    (2) The production costs and time can be reduced since only the cylinder requires to be treated by heat. 
         [0022]    (3) It takes less time for machining since a high pressure port and a low pressure port communicate directly with a high pressure space groove and a low pressure space groove, the efficiency of the apparatus becomes good due to minimization of the loss of fluid in the duct. 
         [0023]    (4) The performance is good since the circular valve is formed within the cylinder liner, thus the flow path becomes short and reduction of pressure is less. 
         [0024]    (5) The hitting strength can be controlled according to the properties of the material to be crushed since a hitting distance and the hitting interval of the piston can be easily adjusted by opening or closing a short flow path hole using a hole adjuster. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0026]      FIG. 1  is a side sectional view illustrating a hitting body for a hydraulic hitting device according to the present invention; 
           [0027]      FIG. 2  is an enlarged a side sectional view illustrating “A” portion of a hitting body for a hydraulic hitting device according to the present invention; 
           [0028]      FIG. 3  is an enlarged a side sectional view illustrating “B” portion of a hitting body for a hydraulic hitting device according to the present invention; 
           [0029]      FIG. 4  is a side sectional view illustrating a state of mounting an operating unit on a hitting body for a hydraulic hitting device according to the present invention; 
           [0030]      FIG. 5  is a side sectional view illustrating a hitting body for a hydraulic hitting device according to another embodiment of the present invention; 
           [0031]      FIG. 6  illustrates a hydraulic breaker of the conventional hydraulic hitting device; and 
           [0032]      FIG. 7  illustrates a basic hydraulic circuit according to the present invention. 
       
    
    
       [0033]    Descriptions on reference numbers for the major components in the drawings
         1 : hitting body     10 ,  100 : body     11 : flow path groove     12 : flow path hole     20 : upper Body     30 : fixture     40 : operating unit     50 : piston     51 : hitting portion     52 : lower piston     52   a : lower projection     53 : upper piston     54 : operating portion     54   a : operating projection     54   b : upper middle operating projection     102 : liner fixing projection     110 : connecting portion     120 : separating projection     123 : high pressure space groove     123   a : high pressure port     124 : low pressure space groove     124   a : low pressure port     125 : adjusting groove     125   a : adjusting cap     126 : liner fixing hole     126   a : liner fixing bolt     200 : cylinder liner     201 : bottom seal     202 : middle seal     203 : top seal     210 : operating flow path hole     211 : short stroke flow path hole     212  long stroke flow path hole     213 : valve operating flow path hole     215 : lower high pressure inlet hole     216 : upper high pressure inlet hole     220 : low pressure hole     230 : circular valve     230   a : valve middle area     230   b : valve upper area     231 : valve middle hole     240 : seal retainer     270 : return flow path hole     271 : return hole     272 : lower returns hole       
 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0079]    A hitting body  1  for a general hydraulic stroke device according to the present invention having a body  100 , a piston  50  formed at the inside of the body  100 , and an upper body  20  formed on the upper portion of the body  100  includes: a cylinder liner  200  inserted into and formed at the inside of the body  100 ; at least one operating flow path hole  210  and return flow path hole  270  formed at a wall of the cylinder liner  200  respectively; and a circular valve  230  formed between the seal retainers  240 , which are formed at the upper end thereof. 
         [0080]    The body  100  includes a connection portion  110  formed at a lower portion thereof; a hole penetrated through the inside thereof; the liner fixing projection  102  formed on the lower portion of the hole; and a high pressure space groove  123  and a low pressure space groove  124  formed at the inner wall thereof and bounded by a separating projection  120 . 
         [0081]    The high pressure space groove  123  of a cylinder shape formed long along the inner wall thereof and the low pressure space groove  124  of a cylinder shape formed long at the upper end of the inner wall of the body  100  are bounded by the separating projection  120 . 
         [0082]    A high pressure port  123   a  and a low pressure port  124   a  are formed at an upper outer wall of the body  100 , the high pressure port  123   a  being in communication with the high pressure space groove  123  and the low pressure port  124   a  being communication with the low pressure space groove  124 . 
         [0083]    An adjusting hole  125  passed through the high pressure space groove  123  is formed at the outer wall of the body  100  and has an adjusting cape  125   a.    
         [0084]    A liner fixing hole  126  is formed at the bottom of the body  100  and a liner fixing bolt  126   a  is inserted into the liner fixing hole  126 . 
         [0085]    The upper body  20  is formed at the upper portion of the body  100 . If necessary, a gas such as nitrogen is filled in the inside thereof so as to increase the speed at the time of the fall of the piston  50 . 
         [0086]    An accumulator may be attached to the side surface of the body  100 . The accumulator is configured to be communicated with the high pressure space groove  123 . 
         [0087]    The cylinder liner  200  is inserted into the inside of the body  100 . The cylinder liner  200  is inserted into the upper portion of the body  100  and the lower portion of the cylinder liner  200  is fixed to the liner fixing projection  102 . 
         [0088]    The upper portion of cylinder liner  200  is fixed to the body  100 , while the upper body  20  pressing the seal retainer  240 . 
         [0089]    The cylinder liner  200  is formed in a cylindrical shape and manufactured by means of the precision processing and heat treatment, so that the piston  50  ascends and descends very accurately along the inner wall of the cylinder liner  200 . 
         [0090]    The cylinder liner  200  has a plurality of sealing portions on the outer periphery thereof and includes bottom and middle seals  201  and  202  and a top seal  203  formed on the seal retainer  240 . 
         [0091]    The bottom and middle seals  201  and  202  are configured to be in contact with the upper and lower portions of the inner wall of the body  100  respectively and the middle seal  202  is configured to be in contact with the separating projection  120 . 
         [0092]    The bottom and middle seals  201  and  202  and the top seal  203  are configured to prevent the fluid flowed in the high pressure space groove  123  and the low pressure space groove  124  from being leaked to outside. 
         [0093]    A lower high pressure inlet hole  215 , an upper high pressure inlet hole  216 , and a low pressure hole  220  are penetrated through the inner and outer walls of the cylinder liner  200 . The lower high pressure inlet hole  215  and the upper high pressure inlet hole  216  is in communication with the high pressure space groove  123  and the low pressure hole  220  is in communication with the low pressure space groove  124 . 
         [0094]    At least one operating flow path hole  210  and return flow path hole  270  are formed at the wall of the cylinder liner  200  respectively. 
         [0095]    The operating flow path hole  210  includes a short stroke flow path hole  211  and a long stroke flow path hole  212  penetrated through the inner wall of the cylinder liner  200  and a valve operating flow path hole  213  formed at the upper portion thereof. 
         [0096]    The operating flow path hole  210  further includes a closing hole  214  corresponding to the short stroke flow path hole  211  and penetrated to the outer wall of the cylinder liner  200 . Also, a hole adjuster  214   a  is inserted into the closing hole. The hole adjuster  214   a  may be a set screw or a pin. 
         [0097]    The upper high pressure inlet hole  216  is configured to pass through a piston upper chamber C and can be opened and closed by the circular valve  230 . 
         [0098]    The return flow path hole  270  is a flow path for discharging the fluid to outside during the operation of the piston  50 . The return flow path hole  270  includes a return hole  271  passed through a piston operating chamber D, which is formed between the outer wall of the operating portion  54  and the inner wall of the cylinder liner  200 . Also, the upper portion of the return flow path hole  270  is in communication with the low pressure hole  220  and the upper portion of the return flow path hole  270  is in communication with the lower return hole  272 . 
         [0099]    The piston  50  includes an operating portion  54  formed at the middle portion thereof, a lower piston  52  formed at the lower portion of the operation part  54 , an upper piston  53  formed at the upper portion thereof, and a hitting portion  51  formed at a lower end of the lower piston  52 . 
         [0100]    The diameter of the lower piston  52  is larger than that of the upper piston  53 . Accordingly, the entire area of a lower projection  52   a  formed the lower portion of the operating portion  54  is less than that of an operating projection  54   a  formed at the upper portion of the operating portion  54 . 
         [0101]    A fixture  30  is connected to the connecting portion  110  of the body  100  and an operating unit  40  is formed at the fixture  30 . The operating unit  40  may be a chisel or bit rotation mechanism and so on. 
         [0102]    A fixing bracket is formed at the outside of the body  100  so as to be fixed to a heavy equipment such as an excavator or a loader etc. Here, a fluid hose connected to the heavy equipment is connected to the high pressure port  123   a  and the low pressure port  124   a  to be used. 
         [0103]    Another embodiment of the present invention is provided a hitting body  1  for a general hydraulic stroke device according to the present invention having a body  100 , a piston  50  formed at the inside of the body  100 , and an upper body  20  formed on the upper portion of the body  100  includes: a cylinder liner  200  inserted into and formed at the inside of the body  100 ; at least one operating flow path hole  210  and return flow path hole  270  formed at a wall of the cylinder liner  200  respectively; and a circular valve  230  formed between the seal retainers  240 , which are formed at the upper end thereof. 
         [0104]    As shown in  FIG. 5 , further another embodiment of the present invention is provided a hitting body  1  for a general hydraulic stroke device having a body  100 , a piston  50  formed at the inside of the body  100 , and an upper body  20  formed on the upper portion of the body  100  includes: the body  100  having a long upper portion and a connecting portion  110  formed long on a lower end thereof, the upper body  20  integrally formed on the long upper portion of the body  100 ; a fixture  30  and an operating unit  40  inserted into and mounted on an inside of the connecting portion  110 ; a cylinder liner  200  inserted into and formed at the inside of the body  100 ; at least one operating flow path hole  210  and return flow path hole  270  formed at a wall of the cylinder liner  200  respectively; and a circular valve  230  formed between the seal retainers  240 , which are formed at the upper end thereof. 
         [0105]    Hereinafter, the manufacturing method and operation of the hitting body for the general hydraulic stroke device according to a preferred embodiment of the present invention will be described. 
         [0106]    The body  100  is processed in the normal machining and it does not have to perform a heat treatment. However, the high pressure groove  123  and low pressure space groove  124  having a sufficient depth are formed on the inner wall thereof and the high pressure port  123   a  and the low pressure port  124   a  communicated with the high pressure space groove  123  and the low pressure space groove  124  are directly formed on the outer wall. 
         [0107]    The cylinder liner  200  is machined precisely to the inner wall so as to precisely slide on the outer surface of the piston  50 . 
         [0108]    In addition, the cylinder liner  200  is processed through the heat treatment, because there is severely worn due to the reciprocating motion of the piston  50 . 
         [0109]    The cylinder liner  200  is inserted into the body  100  through the upper portion thereof. 
         [0110]    At this time, the lower end of the cylinder liner  200  is touched with and fixed to the liner fixing projection  102  formed at the inside of the body  100  and the liner fixing bolt  126   a  is fixed to the outside of the body, so that the cylinder liner  200  is not rotated by the impact. 
         [0111]    The piston  50  is inserted into the cylinder liner  200  and the circular valve  230  and the seal retainer  240  are fixed to the upper portion thereof. Then, the upper body  20  is fixed to the upper portion of the body  100 . 
         [0112]    In a state assembled as described above, the fixture  30  is connected to the connecting portion  110  of the body  100  and the operating unit  40  is fixed to the fixture  30 . Then, the body  100  is connected to the heavy equipment such as the excavator and the fluid hoses are connected to the to the high pressure port  123   a  and the low pressure port  124   a  so as to prepare a crushing operation. 
         [0113]    In the operation of the piston  50 , the fluid introduced through the high pressure port  123   a  is introduced into the cylinder liner  200  through the lower high pressure hole  215  along the high pressure space groove  123 , so that it boosts the lower projection  52   a  of the piston  50 . At this time, the piston upper chamber C is a low pressure state. 
         [0114]    According to the elevation of the piston  50 , when the lower projection  52   a  passes through a short stroke flow path hole  211  or a long stroke flow path hole  212 , since the whole operating flow path hole  210  is high pressure state, the high pressure is applied to a valve upper area  230   b  and the valve middle area  230   a  at the same time while the fluid being introduced into the valve operating flow path hole  213 . However, since the valve upper area  230   b  is larger than the valve middle area  230   a , the circular valve  230  is pushed toward the lower portion thereof, so that the upper high pressure inlet hole  216  is in communication with the piston upper chamber C through a valve middle hole  231  and then, the fluid of the high pressure is flowed into the piston upper chamber C, thereby applying the pressure to the operating projection  54   a.    
         [0115]    The high pressure applied to the operating projection  54   a  is the same as the pressure applied to the lower projection  52   a . However, since the entire area of operating projection  54   a  is larger than that of the lower projection  52   a , the operating projection  54   a  is larger than the lower projection  52   a  in terms of the magnitude of the pushing force. Accordingly, the piston is momentarily transferred toward the lower portion thereof, so that the hitting portion  51  of the piston  50  hits the upper portion of the operating unit  40 . 
         [0116]    Then, the piston operating chamber D is instantaneously communicated with the return hole  271 , so that the valve operating flow path hole  213  of the circular valve  230  becomes a low pressure state and then, the circular valve  230  is again ascended to close the upper high pressure inlet hole  216 . Accordingly, the low pressure hole  220  is opened, so that the fluid of the piston upper chamber C is discharged. 
         [0117]    At this time, since the short stroke flow path hole  211  and the long stroke flow path hole  212  is also blocked by the outer wall of the operating portion  54  of the piston  50 , the low pressure is maintained inside the operating flow path hole  210 . 
         [0118]    As described above, the high pressure and the low pressure is repeatedly crossed in the piston upper chamber C, so that the piston  50  is moved up and down. 
         [0119]    At this time, the fluid leaked through the gap between the lower piston  52  and the inner wall of the cylinder liner  200  is joined with the return flow path hole  270  through the lower return hole  272 . 
         [0120]    The short stroke the flow path hole  211  can be closed by the hole adjuster  214   a . When the short stroke flow path hole  211  is closed, the piston  50  rises to the long stroke flow path hole  212 , so that the circular valve  230  is operated, thereby increasing the hitting distance of the piston  50 . 
         [0121]    The short stroke flow path hole  211  and the long stroke flow path hole  212  serves to form the high pressure in the operating flow path hole  210  so as to operate the circular valve  230  and form the high pressure in the piston upper chamber C. Accordingly, when the short stroke flow path hole  211  is opened, the hitting distance of the piston  50  and the hitting interval are shortened. Meanwhile, when the short stroke flow path hole  211  is closed and the long stroke flow path hole  212  is opened, the hitting distance of the piston  50  and the hitting interval are increased. 
         [0122]    As described above, since the hitting distance and the hitting time can be adjusted, it can selectively operate the equipment according to the type of the crushing matters. 
         [0123]    In addition, since the high pressure port  123   a  and the low pressure port  124   a  are directly attached to the high pressure space groove  123  and the low pressure space groove  124  formed at the outer wall of the body  100  respectively, the flow path of the fluid is shortened. 
         [0124]    According to the hitting body for the hydraulic hitting device of the present invention, the production costs and time can be reduced since only the cylinder liner inserted into the body requires to be machined precisely; the production costs and time can be reduced since only the cylinder requires to be treated by heat; it takes less time for machining since a high pressure port and a low pressure port communicate directly with a high pressure space groove and a low pressure space groove, the efficiency of the apparatus becomes good due to minimization of the loss of fluid in the duct; the performance is good since the circular valve is formed within the cylinder liner, thus the flow path becomes short and reduction of pressure is less; and the hitting strength can be controlled according to the properties of the material to be crushed since a hitting distance and the hitting interval of the piston can be easily adjusted by opening or closing a short flow path hole using a hole control unit 
         [0125]    As show in  FIG. 7 , the valve of the present invention includes the high pressure port  123   a  and the low pressure port  124   a . Also, the valve includes the valve middle area  230   a  and the valve upper area  230   b . Here, the valve middle area  230   a  is connected to the lower high pressure inlet hole  215 , the valve upper area  230   b  is connected to the long stroke flow path hole  212  is connected to the low pressure port  124   a , and the return hole  271  is connected between the low pressure port  124   a  and the connecting middle portion of the valve, so that it can be applied to the hydraulic circuit. 
         [0126]    The present invention has been described according to preferred embodiments such as the breaker with reference to the accompanying drawings. However, from the basic hydraulic circuit shown in  FIG. 7 , those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Also, the present invention is applied to the other various hydraulic hitting devices to be utilized.