EP 0004946 B1 19811014 - BORE HOLE HAMMER, ESPECIALLY DOWN-THE-HOLE HAMMER
Title (en)
BORE HOLE HAMMER, ESPECIALLY DOWN-THE-HOLE HAMMER
Publication
Application
Priority
DE 2816737 A 19780418
Abstract (en)
[origin: US4280570A] An impact and rotary rock drilling tool for operation by compressed air fed through a three-part control unit that contains a valve and duct system and is housed in a cage mounted to an outer tube. A central spindle tube is positively connected to the control unit and guides a main ram as well as an intermediate ram that rests on top of a steel drill member for reciprocating movement therewith. An insert portion secured inside the central spindle tube, which latter may comprise a check valve at its lower end, has partitions separating a plurality of passages with ports arranged in the central spindle tube for selected flow connections.
IPC 1-7
IPC 8 full level
CPC (source: EP US)
E21B 4/14 (2013.01 - EP US)
Designated contracting state (EPC)
BE CH FR GB IT LU NL SE
DOCDB simple family (publication)
EP 0004946 A1 19791031; EP 0004946 B1 19811014; AT 363427 B 19810810; AT A277979 A 19810115; DE 2816737 A1 19791025; DE 2816737 B2 19800710; DE 2816737 C3 19810319; US 4280570 A 19810728
DOCDB simple family (application)
EP 79101125 A 19790412; AT 277979 A 19790413; DE 2816737 A 19780418; US 3094879 A 19790417