Patent GB-1402778-A (GB)
Title: Gang slitter
IPC: B23D35/00
Filed: 1972-07-27
Abstract: 1402778 Shearing REINHARDT MASCHINENBAU GmbH 27 July 1972 [31 July 1971] 35203/72 Heading B3W  A gang slitter comprising a plurality of pairs of co-operable shearing knives the pairs being mounted on a support for individual displacement therealong in a direction parallel to the axes of the knives, displacing means common to the pairs and adapted to act through first and second coupling means to displace the knife pairs along the support, the first coupling means coupling at least one pair to the displacing means and the second coupling means being for individually coupling the or each other pair to the displacing means and being operable to uncouple the respective pair(s) under the control of pre-set counting means. The cutters 10a, 10b of each unit are driven via spur wheels 8, 42 and 9, 43 by shafts 7 and 6 respectively. A lift-out ring (11) with a rubber ring (12) vulcanized to it, Fig. 2, not shown, is secured to each cutter. The upper and lower parts of each slitter unit frame are connected together only in the wedge shaped area 16, adjacent strips formed by the slitter unit being guided respectively by the upper and lower face of the wedge 16. The slitter unit 20a is directly connected to chaindriven spindle 21 by means of a nut 22 constituting the first coupling means and the units 20a- 20d can be coupled by electromagnets 19a-19c constituting the second coupling means. The units are guided for movement parallel with the axes of rotation of the cutters by a bar 17 and by the engagement of rollers 44a and 44b with a rail 18. Each unit has an hydraulic brake 23 for clamping it to the bar 17. To allow re-spacing of the units each unit is associated with a downward counter to which an input signal corresponding to a metric distance is fed, optionally without stopping the shears. At the end of a count the unit's brake 23 is applied. Pulses are supplied by a generator (27), Fig. 4 (not shown), driven by the spindle 21. To change the spacing between units 20a-20d, the brakes 23 are released and the spindle drives the unit 20a, which pushes the units 20b-20d to the broken line position on the left of Fig. 3, the drive speed having been changed from rapid to crawl when a switch lug 30a on the unit 20a passed a proximity switch 31 or photo-electric cell on the feed table 13. When the switch lug 30d on unit 20d reaches proximity switch 31b, the electromagnets 19a-19c are energized and drive to the right at crawling speed starts. When the lug 30d reaches switch 31c the speed is increased to rapid. As the switch lugs 30a-30d in turn pass the switch 31 the counter associated with that unit, which has been set to a count corresponding to the desired new position, is freed. The unit 20d reaches its new position first, its brake 23 is applied and the electromagnet 19c is de-energized. The spindle drive continues until all the units are positioned the rapid speed being reduced to crawling speed by a signal from the respective counter when each unit is at a fixed distance from the new position. The re-positioning may be controlled by, e.g. punched tapes or cards or magnetic tapes and may be co-ordinated with the operation of a transverse shear upstream of the rotary cutters in a finishing line. If only some of the units are needed, all the units are moved to the broken line position and on the return journey when the switch lug 30d reaches switch 31c the electromagnet coupling the unwanted unit(s) to the train of units is de-energized and the respective brake(s) is/are actuated, the unwanted units being left where there can be readily recoupled to the train when needed.