Device for Cold Expansion of Fastener Holes

Abstract

The invention refers to a device for cold expansion of fastener holes. The device comprises a hydraulic cylinder ( 27 ) in which a piston ( 26 ) with a piston rod ( 25 ) is placed, to whose end a mandrel ( 1 ) of a tool ( 60 ) is fixed. In a flange ( 9 ) a thread is made, through which an immovable fixation of the tool ( 60 ) is implemented, such that in an axial blind hole ( 55 ) of the piston rod ( 25 ), a linear displacement sensor ( 34 ), is positioned, immovably fixed to the hydraulic cylinder ( 26 ). A magnet ( 33 ) is designed for activating the linear displacement sensor ( 34 ), which is connected to the control block ( 38 ). The advantage of the device is in the possibility to control the degree of cold expansion.

What is claimed is: 
     
         1 . A device for cold expansion of fastener holes comprising a hydraulic cylinder in which a piston with a piston rod is placed to whose end a mandrel of a tool is fixed for performing the expansion, in a flange ( 9 ), fixed to the hydraulic cylinder ( 27 ), a thread is made, through which an immovable fixation of the tool ( 60 ) is implanted, in an axial blind hole ( 55 ) of the piston rod ( 25 ), a linear displacement sensor ( 34 ) is placed and fixed immovably to the hydraulic cylinder ( 27 ), between the flange ( 9 ) and the hydraulic cylinder ( 27 ) immovably and coaxially a shutter ( 28 ) is placed, and radial holes ( 49 ,  52 ) are produced in the hydraulic cylinder ( 27 ), through which the working fluid enters respectively piston and rod chambers( 50 ,  51 ) of the hydraulic cylinder ( 27 ). 
     
     
         2 . A device according to  claim 1 , wherein the hydraulic cylinder ( 27 ) is placed in to a plastic casing ( 30 ), having a hollow handle ( 35 ) with a start button ( 36 ) and pipe unions ( 53 ,  54 ). 
     
     
         3 . A device according to  claim 1 , wherein in axial hole ( 58 ) of the piston ( 26 ) are placed a spacer bush ( 32 ) and a magnet ( 33 ). 
     
     
         4 . A device according to  claim 1 ,  2  or  3 , wherein the device is set into motion by a drive system connected to the radial holes ( 49 ,  52 ) of the hydraulic cylinder ( 27 ) and comprising a control block ( 38 ) connected to the linear displacement sensor ( 34 ), a pressure sensor ( 32 ) and electromagnets ( 41 ,  42 ) of a hydraulic control valve ( 43 ), which corresponds in sequence with two ‘throttle controllable-non-return valve’ blocks ( 39 ,  40 ), and through which the drive system is powered by a hydraulic pump ( 46 ). 
     
     
         5 . A device according to  claim 4 , wherein the drive system is equipped with a safety valve ( 45 ) and a pressure gauge ( 44 ), and the working fluid is stored in a tank ( 48 ) and treated through a filter ( 47 ).