Threaded Bar construction and bar stock and nut combina […]
Threaded Bar construction and bar stock and nut combination useful in the mining industry and also in the concrete industry; the bar stock is provided with raised thread segments which appear only on one side of the elongate bar employed, so as to provide for marked reduction in manufacturing costs without detracting from the pull strength or tensioning parameters desired.
The present invention relates to bar stock of the threaded variety and, more particularly, to new and improved threaded bar stock that can be inexpensively made, yet preserving its inherent characteristics as to strength and suitability for engagement with appropriate reaction type bearing nuts; this is accomplished by providing threaded segments only on one side of the elongate bar comprising the bar stock.
Threaded shafts, bars, rods, and bolts are common in various industries. So far as the mining and concrete industries are concerned, it would be highly desirable to be able to manufacture bar stock having threads, headed ends, and the like wherein the cost of manufacturing can be drastically reduced. In times past spiraled threads have been provided bars, rods, shafts and the like. The cost of producing such bars, where the threads are continuous and describe helices, for example, is very expensive. For cost savings, machining of the threads is not an option. Yet, it is difficult to provide uniform threads on bars in another manner.
Din975 have felt that there must be a better way for producing threaded bars where the expense of machining is minimized if not avoid altogether. This patent illustrated thread segments which are not continuous throughout the bar periphery rather are series of segments on opposite sides of the bar, with spacing between adjacent ends of the segments.
In this approach, and by a hot forming process, by way of example, the threaded segments can be produced on opposite sides of the bar by use of a suitable mandrel, forming dies, and so forth, whereby the thread segments can be supplied the bar at substantially reduced cost. The problem here, however, is the fact that in the manufacturing and process of such a bar, it often becomes very difficult to align exactly and in identical pitch the mutually opposite, continuing thread segments on the bar. This is especially true in manufacturing processes that do not employ machining or other expensive fabricating processes.