| 摘要 |
A pin is provided for repairing cracks in a material such as iron casting materials. The pin includes threads with both upper surfaces and lower surfaces which angle upwards toward a head of the pin. A tapping bit is utilized in a hole of similar diameter to the pin, positioned with half of the hole on each side of a crack, the bit creating threads in the hole which are substantially complemental to the threads of the pin. The pin includes a shoulder which has a greater diameter than a diameter of the hole. A neck is located between the head of the pin and the shoulder of the pin having a lesser diameter than any other portion of the pin. When the pin is threaded into the hole, the shoulder abuts against a surface of the cracked material causing the pin to cease translation into the material. Upon further rotation of the pin, the upwardly angled threads draw opposite sides of the crack towards each other. Before a torsional load can be applied to the pin which would damage the threads, the head shears off at the neck. A threaded portion of the pin thus remains within the hole holding sides of crack tightly together.
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