Patent GB-1463595-A (GB)
Title: Machine for producing coil springs
IPC: B21F3/00
Filed: 1974-05-21
Abstract: 1463595 Coiling wire SATO SPRING SEISAKUSHO KK 21 May 1974 [26 July 1973] 22688/74 Heading B3E [Also in Divisions G3 and F2] In the production of coil springs, pulses are produced, in number corresponding to the length of wire 1 fed to a spring forming machine, by converter 42, the pulses being fed to preset {decimal} counters whose contents define; wire length of the spring, and coil diameter and pitch variations, the counters giving control outputs when pulses from converter 42 in number corresponding to their contents have been counted. Pitch control, (I), Fig. 1a (not shown).- After wire has been fed for a distance corresponding to the content of counter (1a), the pitch progressively increases over a distance corresponding to the content of counter (4a) at a rate defined by the content of counter (5a) operating as a divider of the converter pulses. Constant pitch for a distance corresponding to the content of counter (2a) is then maintained, whence pitch is progressively decreased to zero in accordance with the contents of counters (4a, 5a). Counter RC ensures that the distances of progressive increase, resp. decrease of pitch are equal. Length control, II, Fig. la (not shown).- Preset counter 3a contains a number corresponding to the length of wire to be used, its output controlling a wire cutting, and control resetting sequence. Alternatively the latter end of the spring may be formed upon receipt of a signal from proximity switch 51. Diameter control III, Fig. 16.-Fed wire distances at which the rate of change of spring diameter is to change correspond to the contents of counters 7a, 8a, possible sizes of the rate being set in counters 11a, 12a acting as dividers of the converter pulses. The distance at which the sign of the rate is to change is set in counter 6a, the commencement of a portion of constant diameter corresponding to the content of counter 9a, the portion possibly being terminated under control of counter 10a. Typical diameter envelopes are shown at (A-F), Fig. 7, and Fig. 5 (not shown). Control III may be omitted if constant diameter springs are to be formed. The controls (I, II), III provide signals, for pulse motors which may be electro-hydraulic, or for D.C. motors with actual position feedback, controlling members of the forming machine. Position detectors may comprise resolvers, scales using magnetic or capacitance effects, an optical coded plate, or a diffraction grating. Pulse motors may be manually controlled, in single, or jogging, steps by manual control circuitry, Fig. 8 (not shown), for example, for position pre-setting of machine members. Wire feed speed may be greater, for some parts of the spring forming, than for others. Spring forming machine, Fig. 1b, Fig. 2.- The wire is fed through guide 3 by driven rollers 2, pitch being controlled by varying the position of tool 29 in the axial direction of the completed spring. Diameter is defined by the positions of coiling pins 4, (5) on linearly guided members (32, 38) inter-coupled by lever 35 and driven by motor 30. A wedge type coiling arrangement may be used. A cutting tool (29) is reciprocated by a crank-pin and connecting rod arrangement (11, 12), the attainment of top dead centre after a cutting operation resetting the control system. Electromagnetic clutches couple the drives to the machine, and electromagnetic brakes hold any undriven shaft stationary.