Connecting mechanism for thin stainless steel pipe and joint

A connecting mechanism for a thin stainless steel pipe and a joint, comprising:

• the thin stainless steel pipe in which a chevron type projection is formed on an outer periphery of an end portion;
• the joint having an inner diameter configured to allow said thin stainless steel pipe to be inserted thereinto, and having a male thread portion formed in an outer peripheral surface of an end portion;
• a nut having a fitting portion outwardly fitted to said thin stainless steel pipe so as to oppose said chevron type projection and having a female thread portion screwed to the male thread portion of the joint;
• and
• a packing provided between said joint and said thin stainless steel pipe;
• the chevron type projection of said thin stainless steel pipe having two inclined surfaces being formed by expanding a portion of said thin stainless steel pipe with a uniform force caused by inflating in an outer peripheral direction a rubber inserted within said portion of said thin stainless steel pipe portion, a packing fitting portion being formed in said joint and fitting said packing to an inner periphery of an end portion of the joint, an inclined notch portion being formed in an inner end portion of a fitting portion of said nut and being closely attached to one inclined surface of said chevron type projection portion, a joint contact surface being formed in said nut, the joint contact surface being structured such that an end surface of the joint is brought into contact with the joint contact surface at a time when the female thread portion of said nut and the male thread portion of the joint are screwed and firmly attached, and the joint contact surface is defined by an inner diameter difference between said fitting portion and the female thread portion, and said packing being formed such as to be closely attached to each of another inclined surface of the chevron type projection portion formed on said thin stainless steel pipe, and a packing pressing surface and a packing outer peripheral contact surface defining inner side surfaces of the packing fitting portion of the joint as set by the joint contact surface of the nut at a time when the female thread portion of said nut is screwed and firmly attached to the male thread portion of said joint,
• wherein a release groove is formed in the packing outer peripheral contact surface and extends from the packing pressing surface to an opening end portion of said joint.