High-speed mail stacking and separating apparatus

In a high-speed mail stacking and separating apparatus including a stack forming assembly mounted for movement from a stack forming position, for sequential receipt of envelopes from a high-speed envelope feeding means and for support of a stack of said envelopes in a stacking zone, to a stack releasing position, for release of said stack for movement out of said stacking zone, said stack forming assembly including two star wheel assemblies mounted side-by-side for rotation about horizontal axes and said star wheel assemblies each having a plurality of radially extending arms;

• drive means coupled to drive both said star wheel assemblies and counter-rotate said star wheel assemblies to sequentially position one arm after another in said stack forming position and thereafter rotate said arms to said stack releasing position in less time than the time interval between sequentially adjacent envelopes as fed from said high-speed feeding means;
• and stack impeller means mounted for movement into engagement with said stack and for movement to positively displace said stack out of said stacking zone during said time interval between adjacent envelopes to permit said stack forming apparatus to be positioned during said time interval between adjacent envelopes for formation of another stack;
• the improvement in said stacking apparatus comprising:
• said star wheel assemblies each having four radially extending arms, and said arms being Y-shaped with a base portion and a pair of legs extending from said base portion, said legs having an included angle between said legs of 90 degrees and an angle of 135 degrees between said legs and said base portion;
• and
• said drive means positioning the base portions of said arms at 45 degrees above and below a horizontal plane in said stack forming position and rotating said arms by 90 degrees to both positively displace said stack form said stacking zone and to position a second of said arms in said stack forming position to receive another stack.