Damper pressure control apparatus for hydraulic rock drill
Device and method for installing ducts in holes produced by soil
Device for introducing additional air into intake passage leadin
Device for soil sampling under water
Device for the production of earth holes
Drill feed control utilizing a variable overcenter valve
Drill mounting device for backhoe attachments
Drill rig shut-off system
Drilled hole end adjusting arrangement
Dual motor torque delivering tool
Dual speed transmission for automatic assembly machine