Assembling apparatus and assembling method

An assembling apparatus that assembles a retainer by engaging a pair of cotter pieces with an upper end of a valve stem, comprising:

• a first assembling head configured to place the retainer on a valve spring provided to surround the upper end of the valve stem and assemble the retainer;
• a first moving unit configured to move the first assembling head between a supply position of the retainer and an assembling position;
• a second assembling head configured to hold the pair of cotter pieces and engages the pair of cotter pieces with the upper end of the valve stem;
• and
• a second moving unit configured to move the second assembling head between a supply position of the pair of cotter pieces and the valve stem,
• wherein the first assembling head comprises:
• a holding unit configured to hold the retainer at a lower end;
• and
• a push unit configured to push out the retainer held by the holding unit,
• wherein the first moving unit comprises:
• a horizontal moving unit configured to move the first assembling head in a horizontal direction;
• and
• an elevating unit configured to raise/lower the first assembling head, and
• wherein the push unit comprises:
• a push member supported to be able to advance/retreat along an elevating direction of the first assembling head by the elevating unit;
• and
• a biasing member configured to bias the push member in an advancing direction.