close collar 上市 Deposited
Heavy steel plate, perforated to the exact size of the finished coin, fitting around and above the neck of the lower die, defining the cylindrical space (coining chamber) in which the planchet is struck. It insures that the coins will all be of equal diameter; if grooved, it imparts vertical edge reeding. After striking, the upper die retracts, and the lower die rises through the collar, ejecting the finished coin so that feeder fingers or layer-on can brush it into the receiving bin with its fellows, while another planchet is fed to await striking. A flywheel governs all these motions. Newman-Bressett {1962} calls the contrivance a collar die, but the term "close collar" appears in Mint correspondence as early as 1829, when it was introduced for use on half dimes and gold coins, rendering the Castaing machine obsolete. Compare open collar.
- Breen Encyclopedia