Installation Sequence –Single Action with Drive Washer (“U” code)
(With Drive Anvil Washer)
This installation cycle applies to the UNIMATIC® single action blind rivet with drive anvil feature. (Code "U" in the part number, (NAS1919U & NAS1921U) All rivet diameters are installed with a single long life nose assembly.
|Step one |
The blind rivet has a drive anvil washer pre-assembled to the spindle. This anvil serves a means to set the lock collar and allow the installation tool to install 3 rivet diameters with a single nose assembly. The fastener is inserted into a properly sized hole of the correct thickness and the installation tool is attached to the pintail portion of the spindle. The fastener should be inserted completely into the hole with light pressure to insure proper head seating.
When the installation tool is actuated the driving force is applied to the drive anvil as the spindle is pulled into the sleeve. The extruding land on the spindle expands the sleeve to fill the hole as it is pulled through.
When the head of the spindle comes in contact with the sleeve end the sleeve will bulb creating a large bearing blind head. When the spindle shoulder comes in contact with the sleeve counterbore motion stops and the lock collar is inserted into the lock groove on the spindle.
With continued pull force the drive anvil packs the lock collar into the combined cavity of spindle lock groove and sleeve conical seat. The spindle force builds up until the pintail is separated from the installed fastener at a pre-determined load completing the installation. Spindle break leaves a flush surface often not requiring shaving for an aerodynamic surface.