Performing Mechanical Strength and Torque Studies for Weight Reduction in Norm One Way Patented Product

Abstract

Today, there are specially developed fasteners for situations where the need for security and permanent connection is at the forefront. The first thing that comes to mind is the "shear bolt", a fastener that only allows tightening. In this fastener, there is a specially thinned area under the head with machining, and thus, when the bolt reaches a certain torque value, a break occurs in the head part. Thus, a permanent connection is obtained since the hexagon part used only during tightening is eliminated. One of the disadvantages that arise with the use of shear bolts is that there is a significant amount of material used only during tightening and it increases the cost. In addition, uncoated area on the fracture surface makes possible corrosion problems and an extra cost from machining is another disadvantage. The disposal of the broken head part during mass production also appears as an extra cost. In order to prevent these problems, the Norm One Way (NOW®) product, whose patent belongs to Norm Cıvata, has been developed. Thanks to the special head and socket geometry, tightening is done only in one direction and disassembly is not possible. In this study, the effect of increasing the socket depth on the head strength of the bolt was investigated using experimental, analytical and finite element methods. As a result, NOW® product was obtained which is safer, has a head form that will eliminate the possibility of stripping during assembly and at the same time provide maximum weight reduction.