Automatic carriage stop for screw threading lathe - lever contacts stop at end of pass and actuates return

摘要

A lever (31) and arm (27) on the drive shaft (19) engage the leadscrew until a stop (23, 23a) releases a ratchet mechanism (32, 38, 39). A screw (33) is used to adjust the ratchet and a manual override (44, 45, 47) is fitted. If a retractable tool post is used, the lever closing a switch (48) causes it to retract. A time delay can be incorporated, to operate before the carriage can return to its start position. A second switch (41) keeps the carriage return circuit inoperative whilst the drive shaft is in engagement and closes it when the shaft is disengaged.