Apparatus for angularly positioning a rotary member

An apparatus for angularly positioning a rotary member, comprising:

• first drive means connectible to rotate said rotary member in a work operation;
• power transmission means operable to connect said first drive means with said rotary member for rotating said rotary member in a work operation;
• second drive means connectible to rotate said rotary member in an angular positioning movement;
• coupling means actuatable to connect said second drive means to said rotary member for rotating said rotary member while said first drive means is disconnected from said rotary member, said coupling means including a pair of complementary clutch members adapted to be engageable at any position and normally biased to a disengaged position relative to each other;
• first detector means for detecting a predetermined angular reference position of one of said clutch members which is positioned to the side of said second drive means and generating a first signal upon detection;
• a controller responsive to the first signal of said first detector means for controlling the movement of said second drive means so as to stop said one clutch member at said predetermined angular reference position;
• second detector means for detecting a predetermined angular reference position of said rotary member, said second detector means being operated by the rotary movement of said rotary member when said rotary member approches to said predetermined angular reference position thereof and generating a second signal upon detection;
• and
• means responsive to the second signal of said second detector means for stopping said rotary member at said predetermined angular reference position thereof;
• said controller sequentially rendering said coupling means engaged after effecting stoppage of said rotary member at said predetermined angular reference position thereof.