Driving support mechanism for an orbiting scroll of a scroll type fluid displacement apparatus

Claim 1

In a scroll type fluid displacement apparatus including a housing having an inlet port and an outlet port, a fixed scroll fastened to said housing and having a first end plate from which a first wrap extends into an operative interior area of said housing, an orbiting scroll having a second end plate from which a second wrap extends, said first and second wraps interfitting at an angular and radial offset to make a plurality of line contacts to define at least one pair of fluid pockets within said operative interior area, a driving mechanism connected to said orbiting scroll to drive said orbiting scroll in an orbital motion, and rotation preventing means for preventing the rotation of said orbiting scroll so that the volume of the fluid pockets changes during the orbital motion of said orbiting scroll, the improvement comprising a driving mechanism including a drive shaft rotatably supported by said housing, a crank pin axially projecting from an inner end of said drive shaft, said second end plate of said orbiting scroll having a centrally located opening, said crank pin being rotatably carried in said centrally located opening by a bearing, a radial flange fastened to the inner end of said crank pin and spring means disposed between said radial flange and said bearing for urging said orbiting scroll against said rotation preventing means.