Plate advancement mechanism for roofing tool

A plate advancement mechanism for separating individual roofing plates from a stack consisting of first roofing plates alternating with second roofing plates, said first and second roofing plates having an indexing edge with an indexing notch and a trailing edge perpendicular to the indexing edge, the indexing notch of the first plates located in a first position along said indexing edge and the indexing notch of the second plates located in a second position along said indexing edge, said plate advancement mechanism comprising:

• a body configured to accommodate the stack of roofing plates, said body defining an opening for receiving roofing plates and an opening beneath the stack of roofing plates for dispensing a lowermost plate from the stack;
• a shuttle mounted to the body for horizontal movement between a feed position and a plate releasing position, said shuttle including a projection configured to engage the trailing edge of a plate released from the stack onto the shuttle when the shuttle is in the feed position,
• an indexer mounted to the body for reciprocal movement parallel to the indexing edge of said roofing plates between a first feed position and a second feed position, said indexer including an indexing tab projecting beneath the indexing edge of said plates, said indexer first feed position aligning the indexing tab with the indexing notch of the first roofing plates and said indexer second feed position aligning said indexing tab with the indexing notch of the second roofing plates;
• wherein said indexer alternates between said first feed position and said second feed position in coordination with said shuttle to release the lowermost roofing plate from the stack onto the shuttle by aligning the indexing tab with the indexing notch of the lowermost plate, whereby the indexing edge of the lowermost plate is not supported by the indexing tab and falls onto said shuttle while the next plate in the stack is supported by the indexing tab, the projection of the shuttle engaging the trailing edge of the lowermost plate as the shuttle moves from the feed position to the plate releasing position to separate only the lowermost plate from the stack and move the lowermost plate to the dispensing position.