AIR HAMMER Russian patent published in 2006 - IPC E21B4/14 

FIELD: percussion mechanisms used as drilling means to drill wells for underground and opened mineral deposit development.

SUBSTANCE: air hammer comprises cylinder, connected with adapter from one cylinder side. The adapter is provided with peripheral and central orifices. Another cylinder end is connected with head having drilling bit and purging orifices. Piston with central widened part is arranged inside the cylinder. Piston has shank formed on the first piston end and adapted to be inserted in central channel of valve box located between the piston and the adapter. Another piston part is provided with striking means passing in central head channel. Piston comprises central channel and tubular slide with solid partition and side windows located in the central channel. The side windows are formed from both sides of the partition. Inner central channel surface has two grooves formed one over another. Upper groove is communicated with underside piston cavity by -shaped channel. Lower groove is connected with piston head cavity by -shaped channel. In working position slide windows alternately communicate with upper and lower grooves to supply energy carrier medium to head or underside piston cavities so that air hammer performs working or idle stroke. Slide is moved by lower spring and stepped valve box having stepped central channel provided with tubular energy carried medium distributor. The distributor has bead, which alternately closes -shaped channel outlets communicated with central channel of valve box and supply energy carrier medium to head piston cavity on the shortest route. Piston shank switches-over distributor to supply energy carrier to provide working stroke of the piston, wherein at the end of idle stroke shank creates distributor displacement pulse at low velocity of shank impact upon lower end of distributor bead along with following applying manifold pressure action to the bead.

EFFECT: elimination is threaded shank connection with piston.

1 dwg