Patent GB-512977-A (GB)
Title: Improvements in or relating to machines for the manufacture of knitted and woven goods
IPC: D03C19/00
Filed: 1938-09-10
Abstract: 512,977. Looms. TANDLER, W. S., and WALKER, D. Sept. 10, 1938, No. 26489. Convention date Sept. 11, 1937. [Class 142 (i)] [Also in Groups VIII and XL] The needles of a knitting-machine or the healds of a loom can be selected by electromagnets under the control of a photo electric scanning device, the pattern sheet of which has designs in more than two colours, transparencies or reflecting surfaces. Patterned fabric having threads of three colours or stitches of three kinds can thus be knitted using only one pattern sheet. The pattern sheet may have areas of grey, green or black, or may be of oxidised, polished or sand-blasted metal, or when a transparent sheet is used may have areas of colouring material of different light-transmitting power. As applied to a circular machine, for knitting patterns in three colours, jacks 22 are arranged beneath the needles, and electromagnets 29, 40 are arranged at positions displaced around the needle circle for projecting the jacks into tracks 36, 41. At the magnet 29, a first selection of jacks is made, the jacks passing along the track 36 to be raised by a cam 38 so that the corresponding needles take the first thread. At the second magnet 40, selected of the remaining needles pass into the track 41 and are raised by the cam 42, the corresponding needles taking the second thread. The remaining jacks are raised by a cam 45 so that their needles take the third thread. The pattern sheet 51 is mounted to rotate with the needle cylinder 20 and the scanning means are moved longitudinally of the sheet. A scanning device is provided for each magnet 29, 40 and comprises a carriage 52 mounted for movement upon screws 53a, 53b of different hand. The screws 53a, 53b are rotated by gearing including a clutch member 65 operated by trip members 80, 83 at the two sides of the travel of the carriage. A light source 68 directs its beam on to the pattern sheet and the beam is reflected to a photo electric cell 71. The current from the cells 71 passes through amplifiers 73a, 73b to the magnets 29, 40. The cells 71 are so arranged that upon light impinging upon an area 76, e.g., grey, current flows through the cell corresponding to the magnet 29, and upon the light beam impinging upon the area 76 and an area 77, e.g., green, current can flow through the cell corresponding to the magnet 40. No current flows through either cell when the beam strikes the area 78, e.g., black. As applied to a flat-bed knitting machine having jacks 86 disposed below the needles, levers 89, one to each jack, are provided for actuation by an electromagnet 99, which serves to bring the front end of the lever 89 into register with the end of the jack. When the levers have been so positioned, all the levers are moved forward by a. bar 87 to operate the needle jacks. The selected needles take the first thread and knit. The magnet 99 is mounted within 92 slidable along the needle bed to engage seriatim the levers 89, and the housing carries a cam which on the return stroke of the housing moves. the selected levers 89 out of register with the jacks and also to a position in which they are not actuated by the magnet. During the second traverse of the housing 92, a selection of the remaining levers 89 is made by the magnet 99 and the needles corresponding to these selected levers take and knit the second thread. On the return stroke, these selected levers also are moved to inoperative position, and on the third traverse, the remaining needles knit the third or ground thread. The pattern sheet 120 is rotated intermittently, and the scanning means is mounted in a block 94 movable with the housing 92. The scanning means comprises a light source 126 and a photo electric cell 127, and three electric circuits are provided so that the magnet 99 can in one circuit be energised by the light beam impinging on a grey area 121, in the second circuit when the beam strikes the grey area 121 or a green area 122, and in the third circuit the magnet is energised all the time. The change in the circuit is effected by introducing either one, two, or three batteries, 131a, 131b, 131c, of such potential that, e.g., no current passes through a valve 130 when the battery 131a only is introduced and when the grey area is being scanned. A second valve 136 supplies current to the magnet 99 only when no current passes through the valve 130. The switch 133 controlling the batteries 131a, 131b, 131a is shifted from one contact to the other between successive traverses of the scanning means. In a modification, Fig. 9 (not shown) the scanning means comprises two photo electric cells in front of which are placed different light filters, and means are provided for placing first one cell into the magnet circuit, and then the other cell.