TECHNIQUE FOR REDUCING THE VARIABILITY BETWEEN SPT APPARATUSES

A METHOD OF ESTABLISHING A STANDARD SPT TEST IS PROPOSED. IT INVOLVES ELIMINATING RANDOM ERROR BY MEANS OF EITHER AN AUTOMATIC TRIP MONKEY OR A SWING-OUT DROP WINCH. BOTH OF THE PROPOSED DESIGNS CAN BE RETROFIT TO EXISTING HAMMER SYSTEMS AT MINIMAL COST AND EXPENSE. IN ORDER TO ELIMINATE SYSTEM ERROR BETWEEN HAMMER MODELS, A METHOD OF TUNING THE DELIVERED IMPACT ENERGY IS SUGGESTED. CONFORMANCE WITH ASTM DIMENSIONAL STANDARDS IS PRESERVED BY ALTERING THE HAMMER/ANVIL SPECT RATIO, OR BY USE OF CUSTOM CUSHION BLOCKS. THIS WILL AVOID TROUBLESOME CORRECTION FACTORS AND PRESERVE THE BUSINESS BASE OF EXISTING HAMMER PRODUCTS. A 60 PERCENT ER(I) IS SUGGESTED AS A GOAL IN ORDER TO REMAIN COMPATIBLE WITH THE ESTABLISHED INTERNATIONAL DATA BASE.