Reciprocating impact hammer

A method of operating an impact hammer having (a) a drive mechanism, (b) a housing, (c) a variable volume vacuum chamber, (d) a reciprocating hammer weight, at least partially located within the housing and capable of reciprocating along a reciprocation axis, (e) a striker pin having a striker pin longitudinal axis extending between a driven end of the striker pin and a working surface impact end of the striker pin, (f) a nose block formed from a portion of the housing and positioned substantially about the striker pin between the driven end and the working surface impact end with respect to an impact axis that is coaxial or parallel to the reciprocation axis, wherein the reciprocating hammer weight is fitted with at least one composite cushioning slide on an exterior surface of the reciprocating hammer weight, the at least one cushioning slide comprising:

• an exterior first layer, formed with a first layer exterior surface configured and oriented to come into at least partial sliding contact with the containment surface during a reciprocating movement of the reciprocating hammer weight, and
• an interior second layer, located between the exterior first layer and the reciprocating hammer weight, the interior second layer at least partially formed from a shock-absorbing material,
• wherein the first layer exterior surface is a lower-friction surface than the interior second layer, the exterior first layer being formed from a material of predetermined friction and abrasion resistance properties, and
• wherein the at least one upper vacuum sealing is at least partially provided directly by the at least one composite cushioning slide, and
• wherein the striker pin is located within the housing such that the working surface impact end protrudes from the housing and wherein the striker pin is positioned to move substantially along a linear impact axis that is coaxial or parallel to the striker pin longitudinal axis and coaxial or parallel to the reciprocation axis, the method comprising:
• a) contacting the working surface impact end of the striker pin to a working surface to be broken;
• b) operating the drive mechanism to begin lifting the reciprocating hammer weight such that a volume of the variable volume vacuum chamber increases and a pressure differential between an atmosphere and the variable volume vacuum chamber is created;
• c) causing an up-stroke stage, in which the reciprocating hammer weight is moved along the reciprocation axis for a distance equal to a hammer weight up-stroke length from a lower start initial position with a minimum hammer weight potential energy to an upper position at an upper distal end of the housing with a maximum hammer weight potential energy;
• d) causing an upper stroke transition, in which hammer weight movement halts before reversing direction along the reciprocation axis;
• e) releasing the reciprocating hammer weight, wherein the pressure differential acting on the reciprocating hammer weight drives the reciprocating hammer weight toward the driven end of the striker pin, and wherein the reciprocating hammer weight moves back along the reciprocation axis for a distance equal to a hammer weight down-stroke length from the upper position to the lower start initial position;
• f) transmitting an impact force from the striker pin to the working surface to be broken;
• and
• g) repeating steps a) through f).