Title (en)

Percussive drill

Title (de)

Bohrhammer

Title (fr)

Foreuse à percussion

Publication

EP 0837214 A3 19991208 (DE)

Application

EP 97117438 A 19971009

Priority

DE 29618066 U 19961018

Abstract (en)

[origin: EP0837214A2] The hammer has a check valve (30) on a base (54) in front of the control housing cover (50). At the bottom of the drill's outer tube (15) is an axially displaceable drill crown (90). This is actuated by a centrally through-bored piston (75) striking its upper surface (89). The piston is guided by a bush (70), which unites with a control housing's lower part (55) and the outer tube. At the upper end of the piston is a cut-off (100), in particular a slide valve. This works in conjunction with a control pin (40). The cut-off has a control bush with radial through holes (101). The bush can be firmly connected to the piston, or is an integral part of it.

IPC 1-7

E21B 4/14

IPC 8 full level

B25D 9/14 (2006.01); E21B 1/30 (2006.01); E21B 4/14 (2006.01)

CPC (source: EP)

B25D 9/14 (2013.01); E21B 4/14 (2013.01)

Citation (search report)

• [Y] US 5562170 A 19961008 - WOLFER DALE R [US], et al
• [Y] DE 9319223 U1 19940224 - WALTER HANS PHILIPP [DE]
• [A] EP 0484672 A1 19920513 - PERMON SP [CS]
• [A] DE 3806407 A1 19890907 - GKN KELLER GMBH [DE]

Designated contracting state (EPC)

AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

DOCDB simple family (publication)

DE 29618066 U1 19961219; EP 0837214 A2 19980422; EP 0837214 A3 19991208

DOCDB simple family (application)

DE 29618066 U 19961018; EP 97117438 A 19971009