Patent ID: 8256088

Claim:
A mechanism for joining first and second parts comprising: a first part with first and second sides and a hole passing therebetween; a second part comprising a shoulder with a stem extending therefrom along an axis, the stem passing through the hole, with the shoulder abutting the first side of the first part and a distal part of the stem extending beyond the second side of the first part; a ring element disposed around the distal part of the stem; wherein the ring element abuts the second side of the first part, and engages a non-threaded contact surface on the stem at a contact angle that converts a radially inward force exerted by the ring element into an axial tensile force in the stem that draws the shoulder of the second part against the first side of the first part; wherein the non-threaded contact surface of the stem is a side surface of a groove in a lateral surface of the stem and the non-threaded contact surface comprises a surface angle of 10-80 degrees relative to a second surface of the first part in a plane of the stem axis.