Turret index system

A turret index system for a punching machine having spaced apart upper and lower turret assemblies, each having a plurality of punching elements carried thereon at equally spaced turret punching stations with each upper and lower station providing functionally complementary punching elements which are rotatable for positioning in alignment with a machine punching axis, wherein the improvement comprises:

• a rotary drive means being drivably connected to said upper and lower turret assembly for synchronously driving said turret assemblies;
• said rotary drive means includes an index gear and said reciprocating drive means includes a rack which meshes with said index gear and being moved by a power cylinder through a predetermined indexing stroke length to rotate said index gear the equivalent of one turret station spacing;
• a reciprocating drive means having a driving connection with said rotary drive means and a shock absorber associated with said rack to decelerate said turret assemblies during a final portion of the indexing stroke length.
• a releasable drive couple means for driving said rotary drive means from said reciprocating drive means and arranged to transmit incremental rotary motion to said rotary drive means to indexably advance both of said turret assemblies the equivalent of one station spacing;
• said releasable drive couple means including a clutch means arranged to transmit incremental rotary motion to said rotary drive means and wherein the rotary drive means includes a drive shaft carrying spaced sprockets thereon, upper and lower roller chains indexing with said sprockets, said chains each having an operative drive connection with one of said turret assemblies for driving each of said turret assemblies simultaneously from said rotary drive means, said drive shaft being positioned remote from said turrets;
• a shot pin means arranged to lock the indexed position of said turret assemblies and provide required corrective repositioning movements to achieve accurate positioning of said turret assemblies relative to said machine punching axis;
• and
• a control system to sequentially control the operation of said rotary drive means, the reciprocating drive means, the releasable drive couple means and said shot pin means whereby selected turret assembly punching stations are accurately indexed relative to said machine punching axis.