Fastener-driving device and controlling method

Abstract

The driving device 1, in accordance with the invention, has a ram 3, which, driven by compressed air, drives in the fastener 2. A pump device 5 produces the compressed air. The pump device 5 has a pump cylinder 23, a pump piston 22, and an annular magnet arrangement 28, 46 around the pump cylinder 23. The pump piston 22 can move in the pump cylinder 23, along an axis 11. An axial closure 25 of the pump cylinder 23 closes off, with the pump piston 22, a pump volume 27 within the pump cylinder 23. The annular magnet arrangement 28, 46 has a magnetic coil 28, which encloses the pump cylinder 23 and which overlaps, along the axis 11, at least in part, with the magnetizable closure 25 and, in part, with the magnetizable pump piston 22.

1 . A driving device to drive in fasteners, comprising a compressed air driven ram, and a pump device producing the compressed air, wherein the pump device comprises a pump cylinder having a pump volume, a magnetizable pump piston that moves in the pump cylinder along an axis, a magnetizable axial closure, which, with the pump piston, closes off the pump volume within the pump cylinder, and an annular magnet arrangement with a magnetic coil, wherein the magnet arrangement encloses the pump cylinder and the magnet arrangement overlaps, along the axis, at least in part, the magnetizable closure and, at least in part, the magnetizable pump piston. 
     
     
         2 . The driving device according to  claim 1 , wherein the closure and the pump piston each comprise a soft magnetic material. 
     
     
         3 . The driving device according to  claim 1 , wherein the closure overlaps, along the axis, at least 10% of the magnetic arrangement. 
     
     
         4 . The driving device according to  claim 1 , wherein the pump piston overlaps, along the axis, at least 10% of the magnetic arrangement. 
     
     
         5 . The driving device according to  claim 1 , further comprising a pressure chamber, which provides intermediate storage for the compressed air produced by the pump device. 
     
     
         6 . The driving device according to  claim 5 , wherein the pressure chamber has a volume dimensioned to hold an air quantity for one driving operation to fewer than five driving operations. 
     
     
         7 . The driving device according to  claim 5 , wherein an air quantity held by the pump volume is less than the air quantity provided for the driving operation. 
     
     
         8 . The driving device according to  claim 1 , wherein the ram is rigidly connected with a driving piston and the driving piston is arranged to be capable of closing off a work volume within a hollow guide cylinder, and the compressed air can be fed into the work volume. 
     
     
         9 . A control method for a driving device, the method comprising:
 producing compressed air by feeding a current pulse into a magnetic coil, producing a magnetic field that moves a magnetizable pump piston within the magnetic coil in a pump cylinder; and accelerating a ram with the compressed air, such that the ram drives a fastener in a driving direction.   
     
     
         10 . The control method according to  claim 9 , comprising loading a pressure chamber with compressed air, actuating an operating element by a user, and accelerating the ram with the compressed air from the pressure chamber. 
     
     
         11 . The control method according to  claim 10 , wherein loading of the pressure chamber comprises energizing the magnetic coil with a sequence of current pulses, for multiple back and forth movement of the pump piston. 
     
     
         12 . The control method according to  claim 11 ,
 wherein an amplitude and/or a duration of the current pulses increase within a sequence.   
     
     
         13 . The driving device according to  claim 2 , wherein the closure overlaps, along the axis, at least 10% of the magnetic arrangement. 
     
     
         14 . The driving device according to  claim 2 , wherein the pump piston overlaps, along the axis, at least 10% of the magnetic arrangement. 
     
     
         15 . The driving device according to  claim 3 , wherein the pump piston overlaps, along the axis, at least 10% of the magnetic arrangement. 
     
     
         16 . The driving device according to  claim 2 , further comprising a pressure chamber, which provides intermediate storage for the compressed air produced by the pump device. 
     
     
         17 . The driving device according to  claim 3 , further comprising a pressure chamber, which provides intermediate storage for the compressed air produced by the pump device. 
     
     
         18 . The driving device according to  claim 4 , further comprising a pressure chamber, which provides intermediate storage for the compressed air produced by the pump device. 
     
     
         19 . The driving device according to  claim 6 , wherein an air quantity held by the pump volume is less than an air quantity provided by the driving operation. 
     
     
         20 . The driving device according to  claim 2 , wherein the ram is rigidly connected with a driving piston and the driving piston is arranged to be capable of closing off a work volume within a hollow guide cylinder, and the compressed air can be fed into the work volume.