Patent ID: 8661640
Filing Date: 2014-03-04
Classification: E21C,Y10T

Abstract:
1. A block assembly carrying a sleeved cutter pick for use with a rotary cutting head, the block assembly comprising: a block, a cutter pick, a sleeve, and a piston; the block comprising a bore having an open end and a closed end; the sleeve comprising a tubular body comprising an upper end and an opposite lower end, the body defining a bore extending through the body, the sleeve received in the block bore with the lower end of the sleeve body in the block bore; the sleeve bore and the block bore cooperatively defining a piston bore extending from the closed end of the block bore to an upper end of the piston bore spaced from the closed end of the block bore; the piston in the piston bore and comprising an upper side facing the upper end of the piston bore and an opposite lower side facing the closed end of the block bore, the piston sealingly dividing the piston bore into an upper bore portion on the upper side of the piston and a lower bore portion on the lower side of the piston; the piston slideable in the piston bore relative to the sleeve away from the closed end of the block bore from a lower position to an upper position in the piston bore spaced from the lower position, the sleeve obstructing further motion of the piston from the upper position away from the closed end of the block bore; the cutter pick comprising a head configured to hold a cutter tip and a shank extending from the head to a free end of the shank, the shank received in the bore of the sleeve body, the free end of the shank located in the piston bore between the lower position of the piston and the upper position of the piston; the piston disposed in the piston bore between the closed end of the block bore and the shank, the shank in the path of piston movement from the lower position to the upper position of the piston such that the shank engages the piston as the piston moves towards the upper position, the piston and shank configured so that the piston is spaced from the upper position when the piston engages the shank; and a fluid inlet opening into the block bore between the lower position of the piston and the closed end of the block bore, the fluid inlet configured to be connected to a source of pressurized fluid to flow pressurized fluid into the block bore urging movement of the piston away from the closed end of the block bore; whereby the flow of pressured fluid through the fluid inlet drives the piston to the upper position of the piston, causing the piston to thereby engage and displace the cutter pick relative to the sleeve away from the closed end of the block bore and then to engage and displace the sleeve away from the closed end of the block bore.