GB626936A - Improvements in methods of and apparatus for rolling screws - Google Patents

Abstract

626,936. Rolling screw-threads. STEVENS, A. H. (New Process Screw Corporation). Jan. 31, 1946, No. 3115. [Class 83 (iv)] In a method of rolling into pointed screws between platens, blanks comprising a shankportion 74 and a point-forming portion 100, the point-forming portions of successive blanks are supported at the same height relatively to the platens at the beginning of the rolling operation and each such portion contains an excess of metal which is extruded axially to form sharp incising means. The platens comprise the usual stationary platen 130 and the reciprocating- platen 132, each formed with thread - forming grooves 104. The stationary platen, as shown in Fig. 3 is clamped to a holder 194 by means of a block 198 and screw 210. At the end at which screw blanks are fed in, the holder 194 is chamfered and has at the top an inclined plate 250 along which the blanks are fed. Towards the bottom is a vertically adjustable bent strip, one end 276 of which projects so as to overlap the grooved portion of the die and serves to support and correctly position the lower ends of the blanks at the beginning of the' rolling operation. The height of the strip is adjustable by a screw 256. Instead of the strip 276, the blanks may be positioned by means of an upper plate such as 130f on each die as shown in Fig. 16. The position of the block 194 on the frame of the rolling machine is adjustable by means of bolts passing through elongated holes 218. In order to provide sufficient metal to form a conically-pointed screw with threads extending to or beyond the tip, the end of the blank is formed as shown in Fig. 16, with metal 100 in excess of what is required to form a pointed tip 128. The lower side of each die is curved inwardly towards the central space between them and the grooves 104 so shaped in this portion as to form threads on the conical portion ending in substantially downwardly projecting incising points. The machine for carrying out the rolling operation is shown in Fig. 12. The moving platen 132 is adjustably mounted by means of a clamping block 168 and screw 184 in a slide 162 reciprocated from a crank-pin 178. The stationary platen 130 is similarly mounted in a fixed member 194 and is adjustable by means of screws 224 and clamping bolts 220.