| 摘要 |
467,814. Bolts. CLAYTON, C. E. EVERY-. (Illinois Tool Works) Sept. 23, 1935, No. 26352. [Class 89 (i)] A self-tapping bolt is made with a head 12 and cylindrical holding portion A and a hardened threaded tapping portion B which tapers towards the entering end. The thread on the tapping portion is made substantially uniform in height throughout its length and its crown in V-shaped in cross-section. The outer diameter C of the first complete thread at the entering end is greater than the root diameter of the thread on the holding portion A. The bolt is further provided with an unthreaded neck portion 34 flowing into the head and having a diameter greater than the root diameter of the thread. The entering end of the bolt may be made yielding to facilitate screw-cutting by providing a longitudinal recess 30 such as is described in Specifications 386,083 and 386,895. |
