Patent ID: 8061439

Claim:
A device for breaking rocks, the device comprising: a hollow mast having an upper end portion and a lower end portion that define a vertical axis, the mast having a channel running at least substantially parallel to the vertical axis; a weight slidably disposed in the channel; a weight raising arrangement for raising and releasing the weight to allow the weight to fall within the channel under the influence of gravity; a recoil arrangement comprising: a recoil tube having an internal surface, an external surface, an upper end portion and a lower end portion, the recoil tube operatively connected to the mast so that it can move relative thereto, and so that the internal surface of the recoil tube is located proximate the external surface of the lower end portion of the mast and the lower end portion of the recoil tube extends below the lower end portion of the mast, an upper flange secured to an external surface of the upper end portion of the recoil tube such that the upper flange is generally perpendicular to the vertical axis, the upper flange having an outwardly extending upper surface, an outwardly extending lower surface, and a peripheral edge spanning the upper and lower surfaces, with the peripheral edge having an inwardly extending, generally u-shaped transverse slot, and a lower flange secured to the lower end portion of the recoil tube; an isolator arrangement comprising: an isolator structure secured proximate the lower end portion of the mast and proximate the upper surface of the upper flange, the isolator structure arranged to support the recoil tube, and an isolator plate secured to the isolator structure, with a portion of the isolator plate extending below the isolator structure and with said portion being spaced from the recoil tube and movably received by the transverse slot as the recoil tube moves relative to the mast; a nose block secured proximate the lower end portion of the recoil tube, the nose block having an upper surface and a bore formed through the nose block so as to slidably receive a tool therein; and an impact-absorbing recoil buffer disposed within the recoil tube in a space defined between the lower end portion of the mast and the upper surface of the nose block, the recoil buffer being constructed and arranged to resiliently absorb impact forces imparted to the recoil buffer by the weight.