3 Fundamentals of press design

528 Solid forming (Forging)
Minting presses are designed in a vertical and also horizontal version.
Horizontally working presses are used to produce round coins. This
machine design is characterized by simple operation and a low number
of coin-specific exchange parts (Fig. 6.8.20). Vertically operating presses
can be universally applied for the production of round, multiple-edged
and bimetal coins (Fig. 6.8.21); however, a greater number of coin-specific
exchange parts is required here.
The monobloc press frame made of nodular cast iron offers good
damping properties (cf. Fig. 3.1.1). The press is driven by means of a
controllable electric motor, flywheel, eccentric shaft and knuckle-joint.
The bearing points in the knuckle-joint (friction bearing) are configured
for a maximum specific compression stress of 110 N/mm 2 . The
slide is mounted without backlash in pre-tensioned roller gibs. The
indexed dial feed plate for infeed and outfeed transport of the coin
blanks and coins is driven by means of a synchronous timing belt from
the eccentric shaft. The coin blanks are fed by means of mechanical
hoppers and channels towards the indexed dial feed plate. The ejector
system is directly linked to the slide and safeguarded against overloading.
The coining dies can be exchanged (coining punch and minting
Fig. 6.8.19 Press shop of a modern mint
Metal Forming Handbook / Schuler (c) Springer-Verlag Berlin Heidelberg 1998