EP 0283734 B1 19920429 - PERCUSSIVE DRILLING APPARATUS WITH MOVABLE HAMMER HEAD
Title (en)
PERCUSSIVE DRILLING APPARATUS WITH MOVABLE HAMMER HEAD
Publication
Application
Priority
DE 3710162 A 19870327
Abstract (en)
[origin: US4886128A] A ram boring implement having a pneumatically or hydraulically driven percussion piston, movable axially in a reciprocating manner in a housing, and an axially movable bit which is connected to an end of the housing and acted upon directly or indirectly by the percussion piston, is of a structure which permits a restoring piston, connected to the bit, to be acted upon by the pneumatic or hydraulic pressure during the return stroke of the percussion piston.
IPC 1-7
IPC 8 full level
CPC (source: EP US)
E21B 4/145 (2013.01 - EP US)
Designated contracting state (EPC)
AT BE CH FR GB IT LI NL
DOCDB simple family (publication)
EP 0283734 A2 19880928; EP 0283734 A3 19891108; EP 0283734 B1 19920429; AT E75523 T1 19920515; DE 3710162 C1 19880929; US 4886128 A 19891212
DOCDB simple family (application)
EP 88102534 A 19880222; AT 88102534 T 19880222; DE 3710162 A 19870327; US 17378388 A 19880328