Patent ID: RE40400

Claim:
A scroll-type machine comprising: a first scroll member having an end plate and a first spiral wrap extending therefrom; a second scroll member having an end plate and a second spiral wrap extending therefrom, said first and second scroll members being positioned with said first and second spiral wraps interleaved with each other; a structure for supporting said first and second scroll members for relative orbital movement therebetween whereby said first and second spiral wraps define moving fluid pockets therebetween; a drive member for driving said first scroll member to effect said relative orbital movement between said first and second scroll members; said first and second scroll members being movable between a first normal operating relationship in which sealing surfaces of said first and second scroll members are in sealing relationship to close off respective ones of said moving fluid pockets and a second relationship wherein at least one of said sealing surfaces of said first and second scroll members are spaced apart to define a leakage path between said moving fluid pockets; and a force applying structure independent of said drive member and actuatable to apply a force to one of said scroll members to move said scroll member between said first relationship in which said scroll machine operates at substantially full capacity and said second relationship in which said scroll machine operates at substantially zero capacity while said drive member continues to operate whereby the capacity of said compressor is modulated ; wherein said force applying structure is operated to allow movement of said one of said first and second scroll members into said first relationship for a first predetermined time period and to allow movement of said one scroll member into said second relationship for a second predetermined period of time .