Patent ID: 7004522

Claim:
A suction unit provided with a suction mechanism for attracting a workpiece at one end of a shaft attached in a body, said suction unit comprising: a rotary driving source which is provided with said body and which is driven by an electric signal; a rotary member which is connected to a rotary shaft of said rotary driving source and which is rotated integrally with said rotary shaft; a connecting rod which has one end rotatably supported on a portion of said rotary member offset from a center of rotation of said rotary member; a connecting member on which the other end of said connecting rod spaced by a predetermined distance from said one end of said connecting rod in an axial direction is rotatably supported and which is connected to a shaft inserted into said body, wherein said rotary member is rotated by said rotary driving source, and said shaft reciprocates along said axial direction by said connecting rod; a first shaft-holding section disposed at one end of said body for slidably supporting one end of said shaft, and a spring disposed in said first shaft-holding section surrounding said one end of said shaft, said spring biasing said shaft in a direction for urging said shaft inside said body; a second shaft-holding section disposed at another end of said body for slidably supporting another end of said shaft, and a guide mechanism disposed in said second shaft-holding section surrounding the other end of said shaft for guiding displacement of said shaft, wherein a distal part of said other end of said shaft projects from one end of said body; and means for introducing a negative pressure fluid into said first shaft-holding section, such that when said shaft is displaced, said negative pressure fluid communicates via said first shaft-holding section with a fluid passage that penetrates through said shaft.