Linear Headrest Impact Tester

The Linear Headrest Impact Tester is intended to satisfy the linear requirements of FMVSS 201.  It includes the mechanical test machinery and a separate, floor standing, P.C. based Control & Data Acquisition system.  The entire system operates on standard shop air and 115 V.A.C. electrical power (other voltages available).

The machine consists of the impact stand mounted to a suitable bedplate (4' x 12' pictured), and a freestanding control system.  The impact stand can be mounted to a customer-supplied bedplate with a minor revision to the jackscrew assembly that raises and lowers the entire assembly.  The bedplate pictured has a ground steel surface with a 4" array of ½" – 13 holes tapped through it.  Test samples must be securely anchored before performing the impact test sequence.

The impact ram is driven with standard shop air.  It requires pre-charging a small accumulator to approximately 65 PSI, as indicated on a large rotary pressure gauge and adjusted with a manual precision regulator.  Once the exact charge pressure is determined, it rarely needs readjustment.  With the ram manually pushed back, the rebound latch unlocked and the accumulator charged, the system is ready to fire.

Firing requires a conscious sequence of events to ensure the safety of the operator and any others in the area.  While there is no specific guarding, there are many warnings that need to be sequenced through prior to a firing.  Initially, the system requires a (unique) operator key to enable the firing sequence.  A revolving red beacon begins to run when the charging starts.  Once the system is charged, the firing sequence can be started on the P.C.  A loud horn then goes off in short bursts and then goes continuous just prior to firing.  A special screen on the monitor asks the operator to confirm the desire to fire and requires the holding of a key while a visual count-down timer runs out.  Only then does the system fire.

Data acquisition is performed by a P.C. and captures the impact pulse from two accelerometers in the headform.  Data is then displayed graphically along with HIC, peak deceleration, speed at impact, etc.  The control system is programmed in Visual basic and operates in a Windows type format.  There are many features for cursors, calculations, operator and test sample data input, etc.  When completed, the results can be printed out on plain paper with the included printer, saved internally, saved to a disc, etc.  Anyone generally proficient with standard P.C. functions would have very few problems learning to operate this equipment.

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