Helical grooved pins replace solid dowel pins in folding rear gun sight assembly
06 April 2010
A manufacturer of after-market tactical rifle sights has now specified Spirol helical grooved pns in place of solid dowel pins in the assembly of a folding rear sight. The Spirol pin both absorbs hole tolerances and provides positive retention. A Spirol CRD automatic dual pin insertion machine has also been specified to install the pins.
As part of the assembly process, the operator can easily load the sight into a fixture nest, and he then activates the insertion machine. The inserter advances, simultaneously installs the helical grooved pins, retracts and resets. This machine/pin combination has improved production four-fold and virtually eliminated all scrap.
The manufacturer has also replaced a slotted spring pin within the assembly with an automation-friendly Spirol coiled spring pin and now uses a Spirol PR automatic pin inserter with a custom designed fixture to ensure trouble free pin installation. The operator places the assembly into the fixture, locates the fixture on to a post and then gently pushes the assembly forward to compress the spring. The assembly then moves over an alignment pin, and the machine is activated to automatically install the Spirol coiled spring pin.
This new approach has enabled the manufacturer to dispense with a multi-stage assembly process using the solid dowel pins and slotted spring pins. Furthermore, due to manufacturing tolerances, these pins were occasionally loose, requiring an additional operation to ensure retention. The slotted pin was also not easy to handle due to its small diameter resulting in a slow and tedious process. Any misalignment of the pin resulted in damage to the assembly and therefore alignment and proper pin location were critical. The new approach, using Spirol, has effectively removed these additional problems.
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