Propeller-shaped centering tool

Abstract

This product is a track fastening device, such as a direct-connection 8-type rail fastening device, used in Shinkansen slab track. A key feature of this product is its mounting method, which allows it to be attached to a cylindrical central axis, in preparation for renovation work using new track materials. To ensure stability, a 65mm x 110mm drilling hole is required in the track slab (concrete surface), and a propeller-type centering device is supported at three points. Another feature is that resin can be injected from the top surface. The new track material uses steel pipe inserts (long nuts L80mm, weighing approximately 0.75kg), which are about 12.5 times heavier than conventionally used nuts. Therefore, to maintain balance, the device must be designed to match the weight. Prototypes were created to match the track structure, combining a hexagonal nut screw and a steel pipe insert. The hexagonal bolt is held vertically by hand, inserted into the 65mm x 12mm cylindrical hole, and then precisely fitted onto the central axis while suspended. During resin injection, a load is naturally applied, so the device must be robust. Furthermore, considering the possibility of misalignment and the need for similar weight, the design combines a "propeller-type centering device" and a "steel pipe insert." The front and rear views are omitted as they are the same drawings as the right and left side views. Reference Figure 1, showing the usage state, is a plan view showing the rail fastening device on the Shinkansen Direct Connection Type 8, etc. Reference Figure 2, showing the usage state, is a cross-sectional view showing the position of the new steel pipe insert before insertion. Reference Figure 3, showing the usage state, shows the drilling position, and is a plan view showing the mixing situation after drilling a 65mm hole and injecting resin into the concrete. Reference Figure 4, showing the usage state, is a cross-sectional view showing the setup of the propeller-type centering device and the completion of resin injection.

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