BMS Couplers

The system of BMS-BAR COUPLER utilizes a combination of ‘cold forming’ and cold thread rolling to maximize the thread area potential and in doing so enlarges the thread area enough to provide bar failure away from the coupled joint when subjected to tensile load. The method of ‘cold forming’ is simple – a round accurately predetermined sized steel die set is used to modify the shape of the end to be threaded. The forming load is minimal and applied transversely to the direction of the grain flow of the material, in affect aligning the grain flow of the ribs and core diameter without shearing it. The core diameter of reinforcing bar is typically of an oval form and the ribs give it a more overall round shape. The bar is rotated in the die form a number of times in quick succession whilst the dies apply pressure to the outer diameter limits of the reinforcing bar. The ribs and core diameter are modified to form an accurate round shape suitable to thread roll. The system then rolls the thread on to the bar end. Thread Rolling enhances the material strength and is accepted as the norm’ in most arduous industries such as aircraft, nuclear etc, where high performance connections are required. It not only strengthens the material but provides an extremely consistent and accurate thread form with added benefits in slip, fatigue and stress reversal conditions over cut form.