Tattooing Apparatus Having Linear Drive Mechanism with Magnetic Stabilisation and Dynamic Acceleration Recess

A linear drive mechanism for converting rotary motion into linear reciprocation, the mechanism comprising:

• a pair of guide rods arranged parallel to one another;
• a sliding block mounted on the guide rods for linear reciprocation therealong;
• an eccentric body configured to be mounted on a rotary output shaft, the eccentric body having a bearing seat that is radially offset from a rotational axis of the output shaft;
• a bearing mounted on the bearing seat of the eccentric body, the bearing having an outer ring that engages the sliding block to convert rotation of the output shaft into linear reciprocation of the sliding block along the guide rods;
• a magnetic preload system comprising a first permanent magnet associated with the sliding block and a second permanent magnet associated with a stationary structure adjacent to the sliding block, the first and second permanent magnets being arranged in a like-pole repulsive orientation to generate a stabilising force on the sliding block during reciprocation;
• and
• a recess formed in a surface of the sliding block that faces the bearing, the recess being configured to receive a portion of the bearing at a top-dead-centre position of the eccentric body, the recess having a profiled internal surface that produces an increased acceleration of the sliding block away from the bearing during rotation of the eccentric body past the top-dead-centre position.

A method of operating a tattoo apparatus, the method comprising:

• rotating an output shaft of a motor disposed within a housing to rotate an eccentric body mounted on the output shaft, the eccentric body carrying a bearing on a bearing seat that is radially offset from an axis of the output shaft;
• driving a sliding block in linear reciprocation along a pair of parallel guide rods fixed within the housing by engagement of an outer ring of the bearing with the sliding block as the bearing orbits about the axis of the output shaft;
• stabilising the sliding block during reciprocation by a repulsive magnetic interaction between a first permanent magnet disposed in the sliding block and a second permanent magnet disposed in the housing, the first and second permanent magnets being arranged in a like-pole orientation;
• and
• modifying an acceleration profile of the sliding block during a downstroke by receiving a portion of the bearing into a recess formed in an upper surface of the sliding block at a top-dead-centre position of the eccentric body, the recess having a profiled internal surface that produces an increased downward acceleration of the sliding block as the bearing transitions out of the recess during rotation past the top-dead-centre position.