7 PARALLEL DRIVE-- AN ADVANCEMENT IN ENGINEERING AND DESIGN OF A HEAVY DUTY SLIDE RAIL SHEETING SYSTEM THE OPPOSING VERTICAL RAIL MAY BE ALTERNATELY DRIVEN KEEPING THEM PARALLEL TO ON E ANOTHER EARLY AND SUPERSEDED DESIGNS RELIED ON FIXED VERTICAL MEMBERS THAT HAD TO BE ROCKED INTO POSITION CAUSING VOIDS BETWEEN THE EARTH WALLS AND TEH SHORING SYSTEM
Trademark: 75678458
