| 摘要 |
A new punch anvil is provided for use with an axial punch for use in a fastening system of the kind in which the punch displaces a portion of one sheet member, such as a thin metal sheet, into another sheet to fasten them together, the punch and die cooperating to form a "button" of sideways displaced material that locks the sheets together. The anvil consists of two parts, one of which is of smaller transverse dimension than the other to form a transverse shoulder between them. The anvil end against which the members are clamped to be punched is surrounded by a jaw which is split longitudinally to be in at least two members held assembled by an encircling resilient ring or collar, so that the jaw members can move apart transversely and/or their upper ends in contact with the clamped members can rock apart on the shoulder to release them upon conclusion fo the fastening operation. The jaw members are retained on the anvil as the punch withdraws by an annular ridge cooperating with an annular groove or by two radial pins. The longitudinal position of the anvil member may be adjusted to correspond with the punch stroke by means of a screw-threaded member in a correspondingly internally screw-threaded counter-bore.
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