Automatic Connecting Rod Assembly Gage

A common dilemma in assembly operations is matching mating parts when there are incremental sizes from which to choose. A case in point is Harley-Davidson. The motorcycle manufacturer often had trouble matching the correct size cranks, bearings and connecting rods for its engines. The company needed to be able to sort the rods into two different sizes so that operators could assemble the correct crank bearing into each rod for proper fit.

Edmunds Gages developed an automatic gage consisting of a free-standing gage base, machine control cabinet, air gaging fixtures, robotic pick and place mechanism, and our MicroCAG microprocessor. The connecting rod crank bore is measured in four places to acquire ten measurements. A good part within tolerance is categorized by the minimum size witnessed during measurement. The MicroCAG then directs the part, based on that size, to a station where the part is laser marked with a two-digit code so that assemblers can readily view which mating part goes with it.

The gage cycle time is 15 seconds per part, laser marking included. Since the gage has been installed, there have been zero connecting rod assembly mistakes.