FLAT BED KNITTING MACHINE AND TRANSFER SYSTEMS THEREFOR

Abstract: A transfer system for a flat bed knitting machine uses a loop delivery or transfer cam (10) defining a loop delivering track for needle operating butts at the top thereof and permitting a needle operating butt to follow a loop reception track therebelow, the cam (10) being arranged so as to initially lift needle operating butts to a spreading height, lower the butts, guide them by a flat (11) to hold the butts in position briefly for transfer whilst a loop reception cam (28) is arranged to urge the receiving needle upward as the oppositely arranged delivering needle is held in position on the flat to open the latches of the empty needles by means of the loop. Such transfer can be provided in a compact space for operation in both directions of cam movement by ensuring that a pair of retractable cams (18) are provided at the top of the transfer cam (10) and the flats (11) are arranged symmetrically for transfer in each direction of reciprocation between these retractable cams (18).

Description: TITLE: Flat bed knitting machine and transfer systems therefor DESCRIPTION Field of invention The invention relates to flat bed knitting machines particularly of the V+bed flat type. The invention resides in an improved transfer system for such machines. The invention is applicable to V-bed flat type knitting machines having different arrangemenis of knitting and transfer systems including arrangements with two adjacent knitting systems with a transfer system to either side thereof as well as arrangements with combined knitting/transfer systems. Background of invention When transferring loops between needles in different needle beds of flat bed knitting machines , the latches of the needles to receive loops must be opened so that the loops can enter the hooks of those yarns. The opening has been effected by mechanical latch openers which permit a compact cam system or by using the yarn of the loop over the spreader of the needle about to deliver a loop to prise the latch apart from the hook prior to the hook entering the spreader. The use of yarns for opening the latches has involved transferring systems having a substantial dimension in the direction of carriage traverse (see DT-Patent Specification 2,443,231) in which a relatively low permanent transfer peak is located midway between a pair of high-permanent loop spreading peaks. Summary of invention The invention is based on the surprisingly good transfer obtained using the yarn on the delivering needle for latch opening on a transfer system having a particular, compact configuration. τ_0 According to the invention there is provided a transfe system having a loop delivering or transfer cam defining a loop delivery track for needle operating butts at the top thereof and permitting a needle operating butt to follow a loop reception track ]_5 therebelow, the cam being arranged so as to initially lift needle operating butts to a spreading height, lower the butts, guide them by a flat to holding the butts in position briefly for transfer whilsta loop reception cam is arranged to urge the receiving needle 2o upward as the oppositely arranged delivery needle is held in position on the flat. The transfer operation is preferably effected with ai a retractable cam. A pair of these cams may be arranged symmetrically together with the flats on eit 25 side of a central depression, each cam being in the form of an elongate cam lying against the outside upwardly inclined sides of a central part of the transfer cam. The cam acts to control the height to which needle operating butts are lifted on loop 30 spreading. The flats can be formed on the central part and enable reliable latch opening to be performed with the leading needle height control cam retracted or, preferably,projected. The needle operating butts may be selected to pass above or below the transfer cam as a result of the action of jacks lying below the needles in tricks. It has been found that the effect of the flats on reliable loop transfer is particularly advantageous where loop reception cams are arranged to engage butts of the jacks to lift the needles indirectly for loop reception. Even though the receiving needles are thus controlled indirectly, reliable latch opening can be achieved. The central part of the transfer cam may itself be partly retractable to give a knitting action. The retractable needle height control cams advantageously cooperate with other bolt cams which prevent the passage of needle opening butts to above the needle height control cams. DRAWINGS Figure 1 shows an inside view of a loop transferring cam system of a knitting machine according to the inventio ; Figure 2 shows, different stages of operation of the system of Figure 1; and Figure 3A to C show successive stages of operation during loop transfer. Description of preferred embodiments With reference to Figure 1, a knitting machine has a pair of needle beds with needles having butts as indicated at 2. A cam carriage 4 is fitted over the needle beds to cause the needles in the respective beds to perform synchronised knitting and loop transferring movements. The cam carriage 4 has identical arrangements for the front and rear needle beds each arrangement includes a pair of knitting cam systems 6 and' a pair of loop transferring cam systems 8, one to either side of the pair of knitting cam systems 6. Figure 1 only shows one of the loop transferring cam systems and part of the adjacent knitting cam systems for clarity. The other loop transferring cam systems are arranged analogously. Each transferring cam system is arranged to control a rocking jack 42 (as shown sideways) and the needles. The cam system comprises a needle raising cam means 10 acting on needle butts 2 for delivering loops to receiving needles, a lowering cam 12 midway along the length of the cam means 10 and lowering cam means 14 to the side of the cam means 10. At the midway position 16 the needle butts will be lowered by the cam 12 to relax the loops and permit a better insertio of the loop receiving needles and raised by the cam means 10. Flats are provided at 11 between a central depression in the cam means 10 and the upwardly inclin sides of the cam means 10. The cam means 10 has a pair of recesses 24 on its side near the midway position 16 into which lifting, height control cams 18 may project. With the cam 18 projecte the needle butts are raised to a high level at 20; wit the cam 18 retracted in a leading position, the cam means 10 will only raise needle butts 2 to a low leve initially, followed by a lift to an intermediate level just before the midway position. The cam means 10 hav also a pair of recesses 26 to permit movement of the needle butts 2 for receiving loops. Below the cam means 10 lies a guard cam 27 which separates a low non-knit track and a track for butts of permanently de-activated needles. Below the guard cam 27 -lies -an area with cams for operating on the jacks 42 to raise, rock and lower them. Above a fixed lower cam 40 are mounted a pair of loop reception cams 28 which act on raising butts 46 of the jacks 42 to cause the needle butts 2 to be lifted in the recesses 26. It is to be noted that the jacks will be raised in a single smooth movement. A pair of transfer selection cams 3o lie one on either side of the cams 28 and act on the butts 46 to lift the needle butts 2 onto the sides of the raising . cam means 10. An actuator system 32 is associated with the transferring cam system 8 as well as the knitting cam system 8 and incorporates six solenoids for operating rockers 34 which shift front edges into and out of the paths of pattern butts 50 of the jacks 42 in accordance with pattern requirements. A sideways shiftable presser cam 36 acts on rocking butts 51 of the jacks 42 to ensure that the pattern butts 50 are offered up to the rockers 34 for selection. Cams such as 38 act on lowering butts 48 of the jacks 42 and lower the jacks 42 until, at a predetermined pre-selection level, lobes 44 emerge from the tricks in the needle beds and the presser cams 36 can rock any jacks previously rocked by an actuator to permit a fresh selection to be made. The cam 39 has a reduced height to ensure that the jacks 42 are lowered without the lobes 44 emerging from the tricks for reasons which will be explained. The lifting height control cams 18 can be projected in the trailing position and retracted in the leading position by means of a slide 52 which resets the cams 18 at the end of a traverse. Alternatively the cams 18 may be operated by the slide and a solenoid controlled mechanism as will now be described for the other retractable cams so that the cams 18 can be retracted or projected in the leading position depending on requirements. The cams 28 and 30 are projected in accordance with electronic instructions which are passed to solenoids. The operation of the loop transferring cam system 8 is as follows (see Figure 2) . For selective transferring in a trailing transfer system, the leading transfer selection cam 30 over one needle bed is projected (for the topmost needle bed as seen in Figure 2) whilst the trailing loop reception cam 28 is projected towards the other needle bed (i.e. the lowermost needle bed as seen in Figure 2) The actuator systems 32 on both parts of the cam carriage 4 are then selectively operated in the same manner to rock mutually aligned rocking jacks 42. As a consequence, the raising butts 42 are moved out of the needle bed tricks and engage the cam 40 over the top and bottom needle beds. The butts 42 of non- -selected cams pass under the cam 40 and the associated needles stay down and are not considered further. The projected butts 46 rise on the cam 40 and are secured in the rocked position by the lobes 44. On th top bed the butt 46 slides up the transfer selection cam 30 at stage A shown in Figure 2 and in so doing lifts the needle butt 2 from a low track to place on OV- " the side of the cam means 10 at stage B as shown by the position of the needle butt 2 illustrated in solid lines in Figure 2 for the other needle butts 2 stay down. The jacks 42 take no further part and are lowered to some extent by the cam- 39 and remain in the rocked position in which they have been placed in the actuator system 32. The needle butts 2, which rise up the cam means 10, move into the leading recess 24 where the height control cam 18 is retracted at stage C, past the midway position 10 and rise up to the flat 11 at stage D, whilst spreading the loop over a spreader on the needle. The butts 42 are held in position by the flats 11 on the cam means 10 until stage E and the cam 12 and are then lowered at stage F. Subsequently, the butts 2 are lifted to the trailing flats 11 holding the delivering needle still between stages G and H. The butts 2 are then finally lifted to full transfer height at stage I. The needles are then lowered to deliver the loop up to stage K. Between stages A to G, the receiving needle is stationary subsequent to its initial selection. Then the jack butt 46 commences to lift and the needle is lifted in a continuous motion, whilst the delivering needle is held still between stages G and H. During this period the receiving needle hooks slip to the side of the yarn held on the spreader. The yarn penetrates under the latch and opens it. Thus when the receiving needle reaches the apex of the cam 28 at stage I, the latch of the receiving needle is open. The delivering needle can now place its spread loop in the open hook of the receiving needle. In a subsequent traverse no transfer may be necessary. The cams 28 and 30 are all retracted and the needle butts 2 will pass under the cam means 10. The jacks 42 will at last be lowered to selection height by the cam 38 for a.subsequent selection and knitting operation. It is possible to rack the needle beds relatively at the end of the traverse and to cause the loops, previously transferred, to be transferred back to the original needle bed but on different needles. This ca be done by projecting the appropriate cams 18, 28 and 30 which will then automatically effect a transfer on the same needles whose jacks 42 have been left relatively high by the cam 39 but in the reverse direction. It is also possible to select certain jacks 42, rock and lift them on the cam 40 without any of the cams 28 or 30 being projected. The jacks 42 are simply left by the transfer system in a rocked attitude. During the subsequent cam carriage movement, a cam 30 and a cam 28 can be projected to effect' a transfer between the needle beds with the transfer system in a leading position. Only one actuator system 32 does control leading and trailing selection and the number of traverse in which no knitting takes place can be reduced. No mechanical latch openers need to be used and the transfer system is compactly constructed. The loop transferring cam system of Figure 1 can be modified as shown in dotted lines to serve for the purpose of transferring and/or knitting. The cam means 10 is then subdivided in a fixed loύer part 64 and a partly and wholly retractable upper part 66. In the knitting mode both cams 18 are projected to control the needle butts 2. When the part 66 is fully retracted, all needles engage the part 64 (after raising by means of jacks 42 and selection cams 30) will perform a knitting operation in either direction of cam carriage traverse. When the part 66 is halfway retracted, long butt needles will transfer and short butt needles will knit at the same time. Stitch cams 68 can be adjusted as shown by the arrows to vary the stitch length. To avoid the lifting of needles to above the cams 18, blocking cams 70 may be inserted. Another mode of operation utilising the same cam system as illustrated previously is explained by reference- to Figures 3A to 3C. The system then is operated to project the leading cam 18 and retract the trailing one. The needles, in both needle beds are initially in a low position (Figure 3A) . The delivering needle is then lifted by the transfer cam 10, rises on the leading cam 18 to spread the loop to be delivered firmly. The needle is then lowered by the cam 12 (Figure 3B) to briefly relax the loop and take some tension of the spreader 80. The needle is then briefly kept level on the trailing flat 11 whilst the receiving needle is lifted (Figure 3C) to penetrate the spreader 80. For the sake of clarity the receiving needle is shown outside the spreader (80). The lifting onto the flat 11 locates the spread loop in an angle formed in the needle stem and the flat 11 is arranged such that the receiving hook just passes below the loop located in the angle or just brushes it aside to pass under the latch if necessary and open it. Because the trailing cam 18 is withdrawn, the delivering needle remains at this level until the loop has been securely received by the hook, if necessary after moving clear of the trailing flat 11. Because of this arrangement the relative location and register of the front and rear cam system is less critical. The retractable cams 18 thus can be used to give good loop spreading in a particular cam area in one direction of carriage traverse, which same area also serves to provide secure latch opening by loops in the opposite direction of carriage traverse. Reliable transfer can be achieved without using mechanical latch openers by a compact cam arrangement having two peaks only.

Claims: CLAIMS ; 1. A flat bed knitting machine including a transfer system having a loop delivery or transfer cam defining a loop delivering track for needle operating butts at the top thereof and permitting a needle operating butt to follow a loop reception track therebelow, the cam being arranged so as to initially , lift needle operating butts to a spreading height, lower the butts, guide them by a flat to hold the butts in position briefly for transfer hilst a loop reception cam is arranged to urge the receiving needle upward as the oppositely arranged delivering needle is held in position on the flat to open the latches of the empty needles by means of the loop. 5 2. A flat bed knitting machine according to claim 1 in which a pair of retractable cams are provided at the top of the transfer cam and the flats are arranged symmetrically for transfer in each direction of reciprocation between these retractable cams. o 3. A flat bed knitting machine according to claim 2 in which the retractable cams are arranged symmetrically together with the flats on either side of a central depression in. the form of an elongate cam lying against the outside upwardly inclined sides of a central part 5 of the transfer cam. 4. A flat bed knitting machine according to claim 2 in which the leading retractable cam is projected and the trailing one retracted in each direction of carriage traverse, 0 5 « A flat bed knitting machine according to any of the preceding claims in which loop reception cams are arranged to engage butts of jacks for lifting needles indirectly for loop reception. 6. A flat bed knitting machine according to any of the preceding claims 3 or 5 in which the central part has a retractable upper portion for defining a path for the-needle operating butts suitable for knitting, the needles being partly lowered by inside faces of the retractable cams lying against upwardly inclined sides. 7. A flat bed knitting machine according to claim 6 in which the retractable upper portion is retractable to a midway position to permit simultaneous knitting and transfer using needle operating butts of different length. 8. A flat bed knitting machine according to claim 6 or claim 7 in which retractable cams are -provided for guiding needle operating butts to the space between the retractable cams. 9. A flat bed knitting machine substantially as shown in and as described with reference to the Figures.

Inventors: TRAUTNER J
Applicants: BENTLEY ALEMANNIA LTD, TRAUTNER J
Application year: 1980
Main classification: D04B15
IPC codes: D04B7, D04B15