Patent ID: 6986394

Claim:
A reciprocable impact hammer for use in a downhole location comprising: a tool support member; a hammer member; a jack mechanism; a connector member; and a transmission, wherein the tool support member and the connector member are in spaced apart relation from one another and each are secured to the hammer member; the tool support member and the hammer member are moveable one relative to the other; the jack mechanism operatively interconnects the tool support member and the hammer member whereby operation of the jack mechanism causes limited separation of the hammer member and the tool support member one relative to the other; the jack mechanism is reversible to permit subsequent collapsing of the hammer member and the tool support member together; the connector member and the hammer member are moveable one relative to the other; the transmission operatively interconnects the connector member and the hammer member; and includes a transmission body, a first transfer member and a second transfer member for converting linear motion of the connector member to rotary motion of the hammer member whereby when a force acts on the connector member via the hammer member and the tool support member operation of the jack mechanism causes initial elongation of the impact hammer followed in succession by: (i) collapsing of the hammer member and the tool support member together such that the hammer member separates from the connector member and imparts an impulse to the tool support member; and (ii) movement of the connector member towards the hammer member under the influence of the force whereby the transmission causes rotation of a remainder of the impact hammer, the second transfer member includes at least one clutch, at least one of which operatively interconnects the first and second transfer members.