| 摘要 |
For the manufacture of a nut, a piece of plate material which is bent to form a tube (9) can be used. This tube can be placed over a mandrel (8) and clamped together around the mandrel, first by means of a pair of spring-loaded dowels (5) and thereafter by two clamping jaws (1, 2). When the mandrel is then withdrawn, a thread-forming tap (12) during rotation in the direction of the thread can be pressed in through the tube to produce an internal thread by deformation. When the tap has passed right through the tube, the direction of rotation is reversed and the tap is screwed out again, after which the nut is finished. For cooling and lubrication, cutting oil is supplied to the tap before insertion into the tube and possibly to the inside of the tube. There can also be used a tap with a shank (13) which functions as the mandrel (8), and at one end of which extends the threading piece (14). In this way the thread is formed when the tap is turned against the direction of the thread, i.e. turned out of the tube, whereby the necessity of having to feed the tap through the tube more than once is eliminated. |
