Nook Industries’ ActionJac is pivotal to spring and bump-stop rating system.

Spring & Bump-Stop Profile

Like all set up components in auto racing, there is no ‘magic’ winning adjustment; each of the car’s pieces needs to work in concert as a single unit to maximize a particular driver’s feel. That’s the case with NASCAR COT (Cars of Tomorrow) modern spring and bump stops.

The coil binding and micro-cellular polyurethane bumpers are an integral part of the suspension workings that are inserted into the front shock shafts to control the travel.

Often overlooked, the spring and bump rubber rates are an increasingly vital part of the suspension performance. Essentially, the spring and bump stop rubber size/stiffness ratings and shock travel combine to allow the front suspension to move during corner entry to nail the splitter to the track.

Having good data acquisition on the assorted spring and bump stops in use acts as an invaluable commodity that can put the suspension back into a proper and optimal operating range.

Test Rating Solution

In an effort to provide more accurate spring and bump stop ratings for today’s top racing teams, Earnhardt Technologies Group (ETG: Mooresville, NC) has recently developed its advanced Spring Bump Stop Rater (SBSR). Essentially, ETG’s SBSR system emulates the vertical forces applied to the springs and bump stops allowing accurate decisions by engineers and crew chiefs; thus maximizing suspension performance.

The SBSR was originally developed as a prototype three years ago to replace the traditional hydraulic testing systems that were noisy, messy, and inaccurate.

These hydraulic systems lacked the necessary precision required for repeatable increments to deliver complete motion control, which is needed to coordinate chassis geometry measurement and data acquisition.

The complexities and advanced capabilities of the SBSR system depend on the accuracy and precision of its linear motion system. ETG sought out the most precise, accurate, and powerful lifting system in the world, The ActionJac Screw Jack system. Manufactured by Nook Industries (Cleveland, OH) the ActionJac Machine Screw Jack provided the exact support needed to bring the SBSR into fruition.

The Nook Precision Actuator Group worked closely with the ETG team to assess needs, make adjustments, and pair the correct solution with the SBSR system in making this project a success.

Coupled with a servo-driven motor, the 5-Ton (5-MSJ-UK) worm gear driven ActionJac Screw Jack system provides pivotal ‘up/down’ motion in small, precise, and repeatable travel increments to test the vertical forces acting on the spring and bump stops on the racetrack–ultimately providing a dynamic rating to control the displacement algorithm.

The SBSR implements a top load cell which measures the load and displacement as they compress the bump stop (or coil-bind the spring). The ActionJac and servo motor controls the ‘up/down’ motion within a variety of controlled travel scenarios and test configurations. The ActionJac is also self locking and holds to a specific set point.

For more information visit www.nookindustries.com.