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Most rehab power chair users are familiar with EZ Lock, the vehicle securement system. A large bolt head is mounted underneath the power chair, and the bolt latches in a base on the vehicle floor. Once clipped in, it locks the power chair in place. Simple enough of a concept, but how does the bolt underneath the power chair effect everyday performance?

How It's Attached
EZ Lock, via a local adaptive driving equipment provider, either welds a nut underneath the power chair, or bolts on a plate or bracket with the nut (shown above). The bolt then threads into the nut, extending beneath the power chair.

Where The Bolt Is Located
Optimally, the bolt is mounted in line, center with the drive wheel axles. This is important because when driving over a threshold or such, the bolt rises with the drive wheels, preventing clearance issues. However, when straddling an object, the bolt can catch, decreasing ground clearance at the bolt head to 1.5 or thereabouts.

However, 6-wheel power chairs can raise a unique issue. The front caster arms on most 6-wheel power chairs compress upward on ramp transitions. As they compress, the center of the power chair usually remains level, driving the bolt head into the van ramp, scraping as the power chair climbs the ramp. Therefore, it's vital to assess proper bolt height and position while still at the driving equipment provider to prevent this issue.

Increasing Bolt Clearance
Obviously, the lower the EZ Lock bolt protrudes, the greater chance of ground clearance issues. However, there's often a solution. The given space is between the dock bolted to the van floor, and the bottom of the power chair. Accordingly, the bolt sticks down to connect with the dock. Often, there's enough clearance for the dock to be raised, thereby allowing a shorter bolt on the power chair, increasing ground clearance. Most vehicle equipment providers automatically do a low-mount dock and a long bolt configuration, so it's important to ask about raising the dock and shortening the bolt to maximize power chair ground clearance.

Safety and Performance
You'll occasionally hear horror stories of a consumer's EZ Lock bolt catching on everything. However, with the bolt placed in line with the drive axles, and configured as short as possible, an EZ Lock system will offer optimal vehicle safety without hampering power chair performance.

Published 12/2012, Copyright 2012,