Patent GB-777650-A (GB)
Title: Improvements relating to spring-coiling machines
Inventor: BACHE JOHN KENNETH
IPC: B21F3/04
Filed: 1955-06-29
Abstract: 777,650. Coiling. SALTER & CO., Ltd., G. Jan. 4, 1956 [June 29, 1955], No. 18731/55. Class 83 (4). [Also in Groups XIX, XXX and XXXV] A spring-coiling machine of the type in which wire is fed against a forming member which deflects the wire to cause it to travel in a circular path, a further member engaging the rear of the coil being formed to give it the desired pitch, cutting means being provided to sever the formed coil, is characterized by the provision of sensing means comprising a displaceable target so situated or set as to be engaged by the outer end of the spring as it is formed to be displaced by an amount dependent on the final axial length of the spring, which displacement, if the length is greater or less than a correct predetermined length, causes to operate a part or parts of, or associated with, the machine. Wire 2 is fed by rollers 1 to deflecting fingers 3 which curve it and, in co-operation with a finger 4 adapted to bear against the rear convolution, form the wire into a coil. The finger 4 is carried by a rod 11 and is moved away from the coil while the first and last turns thereof are formed so that the ends of the spring are close coiled. Such movement is effected by lever means 15, 21 rocked by a cam 9 and moving a cross-head 10 secured to the rod 11. Adjustment of the position of the finger 4 to vary the pitch of the spring is effected by a screw 24 in the lever 15 bearing on the lever 21. The coil is severed by a reciprocated blade 7 co-operating with a fixed blade 6. The spring-sensing means includes a target plate 26 engaged by the end of the spring being formed to rock a flexible arm 33 about an axis perpendicular to the axis of the spring. Just before the cut-off of a completed spring a solenoid 43 (S1, not shown), is energized by cam-operated means to deflect the arm 33 upwardly. If the arm 33 then lies midway between switches 35, 36 on one side and switches 39, 40 on the other side the spring is of the correct length. If the spring is a little too short the switch 36 is engaged, if much too short the switch 35, if a little too long the switch 39 and if much too long the switch 40. Actuation of the switches 35 or 40 stops the machine. The severed springs are dropped through an outlet shoot 63, the plate 26 having been lifted clear by a cable 47 moved by a cam-actuated solenoid 50. If the springs are of the correct length they drop straight through the lower part 65 of the shoot 63. If they are a little short and the switch 36 is engaged, a solenoid 71 is energized to swing a deflecting plate 69 across the shoot 63 to uncover a side opening 66 through which the short spring drops, and similarly for long springs another plate 69 is swung across the shoot to uncover another opening 66 through which the long springs drop. A safety plate 95 on the arm 33 is engaged by an unsevered spring, if the cutter blade is not working, to move the arm 33 to stop the machine. To adjust the finger 4 to vary the pitch and thus to shorten or lengthen the succeeding spring towards the correct length, the screw 24 is automatically adjusted consequent upon actuation of the switches 36, 39 which actuation energizes solenoids S5 or S6, Fig. 17, to rock a pawl 103 on a lever 105 to engage a ratchet wheel 98 on a nut 99, rotatable but not axially movable on the lever 15. Turning of the nut 99 causes the screw 24 to be moved axially. The degree of rotation of the wheel 99 is controlled by stops 109, 110, the stops 110 being mounted on a carriage 129 adjustable by lever means to one of three positions. The ratchet wheel 98 is locked by a member 114 disengaged upon movement of either of the solenoid links 106. The links 106 are connected by a pivoted crosslever 122 which carries a cam to engage and lift the member 114. Two separate ratchet wheels may be formed on the nut, or the ratchet wheel may be formed on the screw. In an alternative arrangement, Fig. 22 (not shown), a wedge member between the end of the screw 24 and the lever 21 is moved by the solenoids to effect the adjustment. Small electric motors or air cylinders may be used instead of solenoids.