The original Operator Controlled Discharge Chute (OCDC) was  patented in 1966 by a major lawn mower manufacturer at the time. Designs have brought is thru several generations since then including manually operated units and the Power Chute which is now the only powered OCDC made.

OCDC serve more than one purpose

1)  The main purpose is to keep grass clippings and debris from being discharged    

      from under the deck and contained within the mower while the OCDC is in the 

      closed position keeping the clippings from being blown onto areas such as 

     flowerbeds, mulched areas and hard surfaces such as drives, sidewalks and  

     play  areas. Once past the area the OCDC is returned to the open position

2)  Most OCDC's can also be partially closed as well. Since most commercial

     Lawn mowers can disburse lawn clippings between 15 and 20 feet the OCDC

     can be closed part way in order to control how far the clippings exhaust the

     mower deck and are thrown from the mower so they are kept from hard  surfaces

     and beautification areas that are close by. 

      When closed the amount of air coming from under the Power Chute is enough

      to create a powerful blower to clear drives, sidewalks and patios of grass

      clippings thus saving slower walking time with your hand held blower

      equipment during cleanups.

4)  OCDC's can also be used partially closed to keep hazards such as

      gravel and  other dangerous objects from being thrown at high speed from under

      the deck  and into nearby by cars and people that could be injured by flying

      debris. Power Chutes are heavily used by municipal government mowing crews

      and those mowing close to roadways.