| 摘要 |
<p>1442185 Safety bolt STANDARD PRESSED STEEL CO 3 Oct 1973 [10 Oct 1972] 46120/73 Heading F2H A safety bolt 10 has a spring ring 40 housed in an annular peripheral groove 30 near its leading end 24 to prevent withdrawal of the bolt from a workpiece without the use of a specific tool for compressing the ring radially inwardly, or loss of the bolt from the workpiece following slackening of a nut 44 due to vibration, &c. The threaded end portion 24 of the bolt has a diameter not greater than, and preferably less than the diameter B of the main shank portion 16. The ring 40 has a circular cross-section of diameter E and, in its free state, an outside diameter F greater than the shank 16 diameter B, and is radially compressible by a sleeve-like tool (not shown) to an outside diameter less than or equal to the shank diameter B. The bottom of the groove 30 comprises a cylindrical portion 32 of diameter C slightly less than (B-2E) and of length D slightly greater than E/2, and a frusto-conical portion 34 expanding from diameter C to a diameter G adjacent the end portion 24. The cone angle alpha is between 1 and 20 degrees, preferably 12 degrees. The depth of the shoulder 38 between the end 24 and the surface 34 is such that when a part of the ring 40 engages the shoulder and the surface 34, the distance of its geometric centre from the bolt axis 52 is less than H/2. The nut 44 is counterbored at 46 to clear the ring 40.</p> |
