Hudraulic hammer with control means regulating the volume in an accumulator

Abstract

A hydraulic hammer for treatment of workable solid materials comprising a hammer housing ( 1 ) containing a striking plunger ( 2 ) movable to and fro in a guide to encounter a tool carried by the hydraulic hammer, a hydraulic cylinder unit ( 3 ) comprising a cylinder chamber and a piston ( 14 ) movable therein and connected to the striking body ( 2 ), a hydraulic accumulator ( 19, 20 ), a hydraulic channel between the hydraulic chamber ( 19 ) of the hydraulic accumulator and the cylinder chamber of the hydraulic cylinder unit, and a valve means ( 4, 11, 12 ) for controlling the flow of hydraulic fluid from the hydraulic accumulator to the cylinder chamber of the hydraulic cylinder unit ( 3 ). The valve means comprises a valve ( 4 ), normally closed, in the hydraulic channel, and a valve-opening mechanism ( 11 ) pertaining to the valve ( 4 ), said valve-opening mechanism being actuated by a trigger ( 52 ), and a control means ( 42, 44, 54 ) are provided to prevent activation of the valve-opening mechanism ( 11 ) before the hydraulic chamber of the hydraulic accumulator has been filled with a volume of hydraulic fluid selectable in advance.

1 . A hydraulic hammer for treatment of workable solid materials comprising a hammer housing ( 1 ) containing a striking plunger ( 2 ) movable to and fro in a guide to encounter a tool carried by the hydraulic hammer, a hydraulic cylinder unit ( 3 ) comprising a cylinder chamber and a piston ( 14 ) movable therein and connected to the striking body ( 2 ), a hydraulic accumulator ( 19 ,  20 ), a hydraulic channel between the hydraulic chamber ( 19 ) of the hydraulic accumulator and the cylinder chamber of the hydraulic cylinder unit, and a valve means ( 4 ,  11 ,  12 ) for controlling the flow of hydraulic fluid from the hydraulic accumulator to the cylinder chamber of the hydraulic cylinder unit ( 3 ), characterised in that the valve means comprises a valve ( 4 ), normally closed, in the hydraulic channel, and a valve-opening mechanism ( 11 ) pertaining to the valve ( 4 ), said valve-opening mechanism being actuated by a trigger ( 52 ), and in that control means ( 42 ,  44 ,  54 ) are provided to prevent activation of the valve-opening mechanism ( 11 ) before the hydraulic chamber of the hydraulic accumulator has been filled with a volume of hydraulic fluid selectable in advance.  
   
   
       2 . A hydraulic hammer as claimed in  claim 1 , characterised in that the control means comprises means for sensing the volume of hydraulic fluid supplied by the pump to the hydraulic accumulator, and means ( 54 ) for pre-setting a selectable quantity of hydraulic fluid that can be supplied to the hydraulic accumulator.  
   
   
       3 . A hydraulic hammer as claimed in  claim 2 , characterised in that a hydraulic pipe ( 55 ) between the pump ( 40 ) and the hydraulic hammer contains a valve ( 56 ) which is set in closed position by control means ( 42 ) when the pre-selected volume of hydraulic fluid has been supplied to the hydraulic accumulator and, after having triggered striking of the hydraulic hammer, is returned to open position by the control unit ( 42 ).  
   
   
       4 . A hydraulic hammer as claimed in  claim 3 , characterised in that the pump ( 40 ) is arranged to supply a volume of hydraulic fluid that is proportional to the total angle of rotation of the pump ( 40 ) during an operating cycle, in that a pulse transducer ( 44 ) is arranged to sense the total angle of rotation of the pump, and in that the control means is arranged to disconnect the flow of pressure oil to the hydraulic accumulator when the pump has rotated a predetermined total angle of rotation, the size of which is adjustable by a setting device ( 54 ) connected to the control means ( 42 ).  
   
   
       5 . A hydraulic hammer as claimed in  claim 1 , characterised in that on the side turned away from the hydraulic fluid the piston ( 14 ) of the hydraulic cylinder unit ( 3 ) is provided with a rod ( 141 ), the cross-sectional dimensions of which are considerably less than the inner diameter of the chamber of the hydraulic cylinder unit and its outlet opening for the rod ( 141 ), so that the rod can be angled in relation to the shaft of the hydraulic cylinder unit, and in that the end of the rod turned away from the piston is swivel-connected to the striking body ( 2 ), and in that the striking body ( 2 ) is controlled with radial clearance in a guide.  
   
   
       6 . A hydraulic hammer as claimed in  claim 5 , characterised in that the swivel connection between the forward end of the rod and the striking body comprises a spherical swivel joint.  
   
   
       7 . A hydraulic hammer as claimed in  claim 6 , characterised in that the swivel joint comprises a spherically rounded forward end of the rod and a corresponding recess in the adjacent end of the striking body ( 2 ).  
   
   
       8 . A hydraulic hammer as claimed in  claim 5 , characterised in that the rod ( 141 ) is rigidly connected to the piston ( 14 ).  
   
   
       9 . A hydraulic hammer as claimed in  claim 2 , characterised in that on the side turned away from the hydraulic fluid the piston ( 14 ) of the hydraulic cylinder unit ( 3 ) is provided with a rod ( 141 ), the cross-sectional dimensions of which are considerably less than the inner diameter of the chamber of the hydraulic cylinder unit and its outlet opening for the rod ( 141 ), so that the rod can be angled in relation to the shaft of the hydraulic cylinder unit, and in that the end of the rod turned away from the piston is swivel-connected to the striking body ( 2 ), and in that the striking body ( 2 ) is controlled with radial clearance in a guide.  
   
   
       10 . A hydraulic hammer as claimed in  claim 3 , characterised in that on the side turned away from the hydraulic fluid the piston ( 14 ) of the hydraulic cylinder unit ( 3 ) is provided with a rod ( 141 ), the cross-sectional dimensions of which are considerably less than the inner diameter of the chamber of the hydraulic cylinder unit and its outlet opening for the rod ( 141 ), so that the rod can be angled in relation to the shaft of the hydraulic cylinder unit, and in that the end of the rod turned away from the piston is swivel-connected to the striking body ( 2 ), and in that the striking body ( 2 ) is controlled with radial clearance in a guide.  
   
   
       11 . A hydraulic hammer as claimed in  claim 4 , characterised in that on the side turned away from the hydraulic fluid the piston ( 14 ) of the hydraulic cylinder unit ( 3 ) is provided with a rod ( 141 ), the cross-sectional dimensions of which are considerably less than the inner diameter of the chamber of the hydraulic cylinder unit and its outlet opening for the rod ( 141 ), so that the rod can be angled in relation to the shaft of the hydraulic cylinder unit, and in that the end of the rod turned away from the piston is swivel-connected to the striking body ( 2 ), and in that the striking body ( 2 ) is controlled with radial clearance in a guide.