Nut installation apparatus, method and controls

Abstract

A nut installation apparatus or head and controls for installing self-attaching nuts, such as pierce nuts, in a panel, without the requirement of a large forming die press assembly. The apparatus includes a nut anchor, which holds the first or end nut stationary, a relatively movable die member, opposite the nut anchor, which supports the panel and a resiliently supported nut guide having a passage receiving nuts in bulk or strip form. The panel is biased into contact with the end nut in the nut guide, by the movable die, to install the nut in a panel. The moveable die is impelled toward the nut anchor by means of a two stage piston assembly having a first stage which supplies pressure limited to the elastic limit of the panel, and a second stage which supplies sufficient pressure to pierce the panel with the end nut. A sensor and switching mechanism is integrated with the apparatus controls to assure proper installation of the nut and prevent damage to the apparatus. The nut anchor is of generally L-shape configuration to provide a rugged construction, to stop-forward movement of the nut along the nut passage and to retain the nut in a fixed aligned position during installation. The apparatus controls contain a dual palm button starter which requires simultaneous actuation by the operator's palms or thumbs, preventing the operator's limbs from coming in contact with the apparatus during use. Where the nuts are in strip form, the apparatus first severs the end nut from the strip and then attaches the nut in the panel, in a separate step.