| 摘要 |
1,211,585. Making springs; coiling. INDUSTRIFJADRAR A.B. 17 May, 1968 [17 May, 1967], No. 23662/68. Headings B3A and B3E. An apparatus for bending or coiling springs in which the tools IV, V and VI for bending or coiling a wire about a mandrel VII have means for passing an electric current through the spring for tempering is characterized in that the current intensity is regulated in relation to the speed of advancing the spring wire by control means comprising a tachometer generator 5 producing a control voltage connected by a voltage divider 6 to resistors 7, 8 and to a unit including a selectable number of diodes 9 in shunt and said unit converting the linear control voltage of the generator so that the voltage actuating the heating current control from being being linear in respect of the rotary speed of the wire feed rolls II and the generator becomes a logarithmic function of said feed and controls the heating current from a rectifier 3 so that heating varies relative to the speed of advance of the wire. The feed rolls are connected to the rectifier 3 the pole 4 of which is connected to the tool V to heat the wire. A device 10 ensures that a minimum current passes through the wire during short standstill periods when a coiled spring is being severed to prevent too great a fall in spring temperature. A wire guide III is provided with a heating coil 11 adjacent the mandrel and a cold air cooling nozzle VIII following the feed rolls. Oscilloscope terminals 12 and 14 are provided for checking the tempering operation. |
