| 摘要 |
998,481. Screw sockets. SARMI, S.A. SOC. D'APPLICATIONS DE RECHERCHES MINIENES ET INDUSTRIELLES. April 10, 1962 [April 28, 19611, No. 13696/62. Heading F2H. A self-boring wall plug has a part threaded bore and comprises a body portion 19 with an integral head 20 at one end and teeth 24 incorporating anchoring grooves 23 at the other end. The toothed end of the body is also radially divided by slots 19a so as to be expansible when driven over a cone 6 (see Fig. 4). An annular groove 22 at the head end is provided so that the head may be sheared off and used as a nut which is screwable on to a threaded member inserted in the body portion. The head portion is externally shaped, e.g. with flats, to facilitate rotation of the plug during boring and for its use as a nut. The plug bore serves as a passage for waste material during the boring period. A retaining groove 21 in the head is provided for a link or pin 29 to temporarily prevent axial movement between the plug and operating socket of a percussive tool during operation. Alternative forms of plug include those with a cylindrical body and prismatic head, cylindrical head and body, prismatic head and body and conical head with prismatic body. |
