Browse Publications Technical Papers 2019-01-0617
2019-04-02

Evaluation of Harness Tightening Procedures for Child Restraint System (CRS) Sled Testing 2019-01-0617

Sled testing procedures should reflect a rigorous level of repeatability across trials and reproducibility across testing facilities. Currently, different testing facilities use various methods to set the harness tension for child restraint system (CRS) sled tests. The objective of this study is to identify which harness tightening procedure(s) produce tensions within a reasonable target range while showing adequate reproducibility, repeatability, and ease-of-use. Five harness tightening procedures were selected: A) FMVSS 213 procedure, B) a 3-prong tension gauge, C) ECE R44/R129 procedure, D) two finger method, and E) pinch test. Two CRS models were instrumented with a tension load cell in the harness system. Seven sled room operators were recruited to perform each of the five harness tightening procedures for ten repetitions apiece on both instrumented CRS using a Hybrid III 3-year-old. The static harness tension measured by the load cell was recorded after each procedure was completed. Data were analyzed for mean, variance, reproducibility, and repeatability. Operator feedback surveys were used to quantify ease-of-use.
The ECE R44/R129 procedure produced harness tensions which were quite low. The two finger procedure produced the highest tensions while the 3-prong tension gauge, pinch test, and FMVSS 213 procedures produced mid-level tensions. Poor repeatability was apparent for all five harness tightening procedures. The FMVSS 213 method ranked lowest for ease-of-use. Operators preferred using the 3-prong gauge, two finger method, and pinch test.
The load cell readings were sensitive to the order and direction in which the operators adjusted the harness components. High amounts of friction within the harness might prevent it from acting as a homogeneous, continuous system. Sequential tightening of the various sections of harness and/or monitoring the tension at multiple locations might be valuable.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

Seatbelt Entanglement: Field Analysis, Countermeasure Development, and Subject Evaluation of Devices Intended to Reduce Risk

2019-01-0619

View Details

STANDARD

Ambulance Litter Integrity, Retention, and Patient Restraint

J3027_201611

View Details

TECHNICAL PAPER

Preliminary Design Research for the Caravan 1 Crew Seat

850856

View Details

X