Patent ID: 7722053

Claim:
A clamp-type joint for a vacuum apparatus, comprising: a center ring; a rubber O-ring that engages with a peripheral edge of the center ring; and an outer ring installed on an outer circumference of the O-ring in a manner that sandwiches the O-ring between the outer ring and the center ring, the outer ring including a base that forms an outer circumferential side, and a pair of brims that respectively extend from a top and bottom of the base toward a center axis of the clamp-type joint, each of the brims including an inner side on which the brims come into contact with the O-ring, the inner side of each of the brims being in the form of a convex sector, the convex sector including an arc that faces the O-ring, a radius of a circle that defines the convex sector being 0.6-2.5 mm and a thickness (t 0 ) of the outer ring satisfying the following formula: t 1 −0.2 ≦t 0 ≦t 1 +0.4, wherein t 1 is a thickness (mm) of the center ring at a point at which the center ring engages with the O-ring.