Device for dampening the oscillation of the arm of a handling equipment of the swingable lever type

Abstract

A handling equipment of the swingable lever type comprises a driving double acting cylinder ( 5 ) having a chamber ( 18 ) in which a main piston ( 15 ) is sealingly mounted, which is slidable as a result of the selective delivery of fluid under pressure from opposite zones of the chamber ( 18 ) of the cylinder ( 5 ). The main piston ( 15 ) is connected to a rod ( 10 ) having a driving end ( 10 a ) which projects from the cylinder ( 5 ) and is associated with a movable arm ( 7 ). The equipment ( 1 ) is provided with a device for dampening the oscillation of the arm ( 7 ), which comprises an axial cavity ( 27 ) formed in the rod ( 10 ) and containing a service fluid. A stem ( 30 ) rigidly connected to the cylinder ( 5 ) and provided with at least one orifice ( 31, 31 a ) for the service fluid is sealingly and slidably mounted in the cavity ( 27 ), so that the movement of the rod ( 10 ) with respect to the stem ( 30 ) is slowed down as a consequence of the flowing of the service fluid through said orifice ( 31, 31 a ), if the sliding speed of the main piston ( 15 ) inside the cylinder ( 5 ) exceeds a threshold speed set by the cross-section of said orifice ( 31, 31 a ).

1 . A device for dampening the oscillation of the arm of a handling equipment of the swingable lever type, which equipment ( 1 ) comprises a driving double acting cylinder ( 5 ) having a chamber ( 18 ) in which a main piston ( 15 ) is sealingly mounted, which is slidable as a result of the selective delivery of fluid under pressure at opposite zones of the chamber ( 18 ) of the cylinder ( 5 ), the main piston ( 15 ) being connected to a rod ( 10 ) having a driving end ( 10   a ) which projects from the cylinder ( 5 ) and is associated with said arm ( 7 ), 
 characterised in that an axial cavity ( 27 ) separated from the chamber ( 18 ) of the cylinder ( 5 ) and containing a service fluid is formed inside the rod ( 10 ), a stem ( 30 ) rigidly connected with the cylinder ( 5 ) and provided with orifice means ( 31 ,  31   a ) for the service fluid being sealingly and slidably mounted in such a cavity ( 27 ), so that the movement of the rod ( 10 ) with respect to the stem ( 30 ) is slowed down as a consequence of the flowing of the service fluid through the orifice means ( 31 ,  31   a ), if the sliding speed of the main piston ( 15 ) inside the cylinder ( 5 ) exceeds a threshold speed set by the cross-section of the orifice means ( 31 ,  31   a ).    
     
     
         2 . A device according to  claim 1 , characterised in that the stem ( 30 ) has an enlarged head ( 29 ) in proximity of which orifice means ( 31 ,  31   a ) for the service fluid are arranged.  
     
     
         3 . A device according to  claim 2 , characterised in that a seal ( 32 ) is interposed between the enlarged head ( 29 ) of the stem ( 30 ) and the wall delimiting the axial cavity ( 27 ) of the rod ( 30 ).  
     
     
         4 . A device according to anyone of  claims 1  to  3 , characterised in that the stem ( 30 ) has an end fixed to a support plate ( 34 ) anchored to the bottom of the cylinder ( 5 ).  
     
     
         5 . A device according to  claim 1 , characterised in that the axial cavity ( 27 ) of the rod ( 30 ) has a variable longitudinal extension for allowing to compensate the variation of the extension of the stem ( 30 ) received inside the cavity ( 27 ).  
     
     
         6 . A device according to  claim 5 , characterised in that a floating auxiliary piston ( 38 ) is arranged in proximity of the end of the axial cavity ( 27 ) opposed to the stem ( 30 ).  
     
     
         7 . A device according to  claim 6 , characterised in that the floating auxiliary piston ( 38 ) is associated with guide means ( 42 ,  46 ) for its axial movement.  
     
     
         8 . A device according to  claim 7 , characterised in that the guide means of the axial movement of the auxiliary piston ( 38 ) comprise a pin ( 42 ) one end of which is connected to the auxiliary piston ( 38 ), while the opposite end is slidably mounted in a corresponding seat ( 46 ) formed in proximity of the driving end ( 10   a ) of the rod ( 10 ).  
     
     
         9 . A device according to  claim 8 , characterised in that said seat ( 46 ) communicates with the outer environment with respect to the cylinder ( 5 ) by means of a vent hole ( 48 ).  
     
     
         10 . A device according to  claim 1 , characterised in that the cross-section of the orifice means ( 31 ,  31   a ) is variable as a result of the movement of an adjustment member which can be controlled from the outside of the equipment ( 1 ).