Impact machine and a method of forming a body

Abstract

The invention concerns an impact machine for forming a body with desired shape of a formable working material through impact action in a forming operation, said impact machine comprising a machine stand ( 6 ), an upper unit which comprises either a lower impact unit ( 3 ), which comprises a counter-impact device, or a stationary anvil, and a central unit between the upper and the lower units. The central unit ( 4 ) comprises one or more carriers ( 30 ), each of which containing and carrying one or a plurality of identically equal tool units ( 32 ), each of which comprising a die ( 34 ) with a mould cavity ( 46 ) for the working material ( 90 ) intended to be formed, said carriers including at least one carrier which is stationary during the forming operation and which contains at least one such tool unit, and that motion devices ( 7 ) are provided for indexing the carrier or carriers in a horizontal plane for positioning the tool units in different function stations (I-V), comprising a forming station (II) and at least one more station.

1 . An impact machine for forming a body with desired shape of a formable working material through impact action in a forming operation, said impact machine comprising a machine stand ( 6 ), an upper unit which comprises an impact unit ( 2 ) with an upper ram ( 14 ) and an upper punch ( 17 ), a lower unit which comprises either a lower impact unit ( 3 ), which comprises a counter-impact device, or a stationary anvil, and a central unit between the upper and the lower units, characterized in 
 that the central unit comprises one or more carriers ( 30 ), which contain and carry one or a plurality of identically equal, tool units ( 32 ), each one of which comprises a die ( 34 ) having a mould cavity ( 46 ) for the working material ( 9 ) that shall be formed, said carriers including at least one carrier which is stationary during the forming operation and which contains at least one such tool unit;    that motion devices ( 7 ) are provided for indexing the carrier or carriers in a horizontal plane for positioning the tool units in different function stations (I-V);    that said function stations comprise a forming station (II) in which the die ( 34 ) is coaxial with the upper punch ( 17 ), and at least one more station which is either a station (I) for filling the mould cavity in the die with working material, or a station (IV) for ejection of the formed body out from the die, or a station for ejection of the formed body as well as for filling the mould cavity;    that the kinetic energies of the movable masses during the forming operation, which comprise a single stroke of the upper ram ( 14 ), are essentially transferred to the working material in the mould cavity and are so great that the working material is plasticised and flows out to fill all parts of the mould cavity, to form said body with desired shape; and    that the counter-action device of the lower unit or said stationary anvil is provided in the region of the forming station, under the carrier, which is stationary during the forming operation.    
     
     
         2 . An impact machine according to  claim 1 , characterized in that said function stations comprise a station (I) for filling the working material into the mould cavity in the die, said forming station (II), in which the die ( 34 ) is coaxial with the upper punch ( 17 ), and also a separate station (IV) for ejection of the formed body out of the die.  
     
     
         3 . An impact machine according to  claim 2 , characterized in that said function stations also comprise a re-setting station (V), in which the mould cavity ( 46 ) for the working material ( 90 ) is re-set to a starting position for filling and forming.  
     
     
         4 . An impact machine according to any of the proceeding claims for forming an annular body, characterized in that the functional units also comprise a mandrel, and that the function stations also comprise a station (III) for driving out the mandrel from the formed, annular body.  
     
     
         5 . An impact machine according to any of claims  1 - 4 , characterized in that it comprises a carrier in the form of a horizontal turntable, motion devices for turning the turntable stepwise about a horizontal axis of rotation for positioning the tool units in the various function stations, which are located at equal angle distances from one another relative to said axis of rotation.  
     
     
         6 . An impact machine according to any of claims  1 - 4 , characterized in that it comprises a carrier in the form of a shuttle, which is movable in a stand, and that motion devices are provided for moving the shuttle to and fro between function stations of the tool units along a linear movement path.  
     
     
         7 . An impact machine according to any of claims  5  and  6 , characterized by devices for fixation of the carrier or carriers, when the carrier or carriers have been moved so that the tool units have adopted a position in a new function station.  
     
     
         8 . An impact machine according to any of claims  1 - 7 , characterized in that a lower punch ( 27 ) is provided in the forming station (II), coaxial with the upper punch ( 17 ) and with a lower ram ( 24 ), that the upper ram and the lower ram are provided to simultaneously perform a single stroke with such a velocity against the upper punch and against the lower punch, respectively, that those masses which move downwards, including the upper punch, get a downwards directed velocity (v 1 ), and those masses which move upwards, including the lower punch, get an upwards directed velocity (v 2 ), wherein the movable parts have such masses and the velocities are so high that the impulses of the downwards directed masses and of the upwards directed masses are essentially equally large, i.e. so that the following conditions will apply: 
       m 1 ×v 1 ≅m 2 ×v 2   where m 1  is the total mass of downwards movable masses at the impact and m 2  is the total mass or the upwards movable masses at the impact, and    that the kinetic energies of the movable masses, i.e.                  m   1          v   1   2       2     ,              and                       m   2          v   2   2       2                ,                     respectively, are essentially transferred to the working material in the mould cavity and are so great that the working material is plasticised and flows out to fill all parts of the mould cavity, when the punches are maximally brought together, for the formation of said body with desired shape; and that the die is essentially stationary during said stroke.    
     
     
         9 . An impact machine according to any of claims  1 - 7 , characterized in that the lower unit comprises a counter-impact device in the form of an anvil in said forming station (II), said anvil being movable in the vertical direction, and motion devices being provided to move the anvil upwards towards the ram which is included in the upper unit to contact the tool unit in the forming station, simultaneously with the ram moving downwards towards the same tool unit.