Patent GB-872162-A (GB)
Title: Improvements in straight bar knitting machines
IPC: D04B11/04
Filed: 1959-03-04
Abstract: 872,162. Knitting-machines. MILLNER, C. K. March 4, 1959 [April 21, 1958], No. 7523/59. Class 74 (2). To facilitate the production of rib fabric on a straight-bar machine, a bed of slidable latch needles is positioned at the front of the machine  adjacent the usual bearded needles. During the production of a rib portion of fabric alternate bearded frame needles are lowered to an inoperative height and a cam carriage is reciprocated over the latch needles to cause them to take and knit the yarn in conjunction with the remaining bearded frame needles of the machine. Simultaneously the catch-bar mechanism is held in a retracted position where it retains the sinkers and dividers inoperative. On completion of the rib portion, the latch needles are fully advanced to enable the alternate frame needles which are reintroduced into operation to penetrate the loops on the corresponding latch needles, whereafter the latch needles are retracted to an inactive position thereby effecting transfer of their loops on to the frame needles. Plain knitting then continues in the usual way. The bearded frame needles are divided into two groups B, C the needles of one group alternating with those of the other and each group being mounted in a separate needle bar 62, 65. The bar 65 is vertically adjustable in relation to the bar 62 and is manually adjusted when it is desired to produce rib fabric so that its needles, being those of group C, are lowered to an inoperative height, Fig. 8. Simultaneously a lug on a pattern chain operates mechanism whereby the catch bar truck lever is supported in the position in which the catch bar and sinkers and dividers are fully withdrawn and maintains them in that position during the period of rib knitting. A lever 164 on a cross-head 157 coupling a rack 156 driven from the coulier mechanism through a pinion 152, is manually detached from engagement with a notch 165 in the connecting bar 41 driving the slur-cock so as to render this mechanism inoperative, Fig. 16. The cross-head 157 is connected to the friction bar driving the friction boxes for the yarn carriers in the usual way. In addition, the pattern chain releases mechanism whereby the latch needle bed may oscillate a small amount about rearwardly positioned pivots so that the latch needles may co-operate with the bearded needles during the formation of the fabric. A second lever 342 also is manually positioned to engage a lug 344 so as to transmit the reciprocatory motion of a second coulier mechanism to a bar 336, Fig. 16. All of these manual adjustments are made when the machine is rendered stationary. The bar 336 is coupled to a further bar 326 by a bracket 337 and serves to drive an arm 321 normally maintained in engagement between lugs 325 on a cam carriage 256, Fig. 27, slidably mounted over the latch needle bed and having cams adapted to engage the butts of the needles. During rib knitting, therefore, the central stitch cam 241, Fig. 32, serves to advance the latch needles between the bearded frame needles of group B where they receive yarn and draw loops about the shanks of the frame needles. The frame needles then knit whilst the latch needles retain their loops. At the end of rib knitting the needle cam 247 is introduced and projects all of the latch needles beyond their normal yarn receiving position so that the loops engage abutments 188 on the latch needles and are spread by spreaders 194 on the side of the needle, Figs. 36 and 37. The machine is again stopped when the frame needles reach their lowermost position and the alternate needles C are raised into alignment with the others of group B. Simultaneously the arm 86, Fig. 1, transmitting the presser motion to the needles is manually adjusted to tilt the frame needles away from the presser edge so that as they rise when the machine is restarted needles of group C penetrate the loops on the latch needles. Further actuation of the carriage 256 then causes the latch needles to be retracted under the influence of cam 251 which has been introduced at the end of the last reciprocatory movement whereby the loops are transferred from the latch needles to the bearded needles. Thereafter the machine is adjusted and manually manipulated to render the latch needles and their associated mechanisms inoperative and to enable the frame needles to continue plain knitting in the usual way. Adjustment of the latch needle cams from an operative to an inoperative position is effected by a stepped cam plate 265 slidably mounted on top of the carriage and being slotted to receive pins 257, 276, 285 projecting upwardly from the cams. Followers are attached to the upper ends of the pins and these engage on cam blocks 270, 282, 292 and are urged downwardly into engagement therewith by springs 275, Figs. 27 and 31. Levers 382 mounted on a shaft 390 are positioned at each end of the carriage traverse and are pivotally adjusted, under the control of the pattern chain, about the shaft 390 to bring their free end into engagement with one or other of the stepped end faces 385, 386, 387 of the cam plate 265 so that as the carriage moves towards either of its end positions a lever 382 is engaged to shift the plate 265 and make the necessary adjustment to the needle cams. U.S.A. Specification 2,326,694 is referred to.