EP0042838B1

EP0042838B1 - Flat bed knitting machine and transfer systems therefor

Info

Publication number: EP0042838B1
Application number: EP80901729A
Authority: EP
Inventors: Johann Georg Trautner
Original assignee: Bentley Alemannia Ltd
Current assignee: Bentley Alemannia Ltd
Priority date: 1979-10-01
Filing date: 1980-09-25
Publication date: 1984-04-11
Also published as: ES8200152A1; DE3067454D1; IT1132901B; WO1981000868A1; IT8025026A0; EP0042838A1; JPS56501248A; ES496068A0; JPS6410617B2

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

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 arrangements 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.
According to the invention there is provided a flat-bed knitting machine of the V-bed type including a transfer system having a transfer cam with raising cam faces defining a loop delivering track for needle operating butts on each side at its upper face and permitting needle operation butts to follow a loop reception track below its lower face to provide loop transfer from either needle bed in either direction of cam carriage traverse characterised in that a retractable cam is provided at the top of each raising cam face which retractable cam is arranged to be projected on the leading side of the transfer cam and to be retracted on the trailing side, the transfer cam having a central portion with flats on either side of a central de^pres- sion between the retractable cams to locate the loop delivering needles at a suitable level to open the latches of the loop receiving needles after the loops have been spread by lifting the loop delivering needle to a higher level on the retractable cams. Each retractable cam may be 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 spreading. The flats are formed on the central part and enable reliable latch opening to tbe performed with the leading needle height control cam 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 having retractable cams for use in a knitting machine according to the invention;
Figure 2 shows different stages of operation of the system of Figure 1 not according to the invention; and
Figure 3A to C show successive stages of operation during loop transfer using a cam system modified from that illustrated in Figure 1 and according to the invention.

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 insertion 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 inclined sides of the cam means 10.
The cam means 10 has a pair of recesses 24 on its sides near the midway position 16 into which lifting height control cams 18 may project. With the cams 18 projected the needle butts are raised to a high level at 20; and with the cam 18 projected in a leading position, the cam means 10 will raise needle butts 2 to a high level initially to give the operation described in Figure 3A to 3C which follows. The cam means 10 have 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 deactivated 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 30 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. Upper and lower sideways shiftable presser cams 36 act 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 may be operated by a slide 52 which resets the cams 18 at the end of a traverse and a solenoid controlled mechanism so that the cams 18 can be projected in the leading position according to the invention. 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. The general sequence of events is as shown in Figure 2 but it should be noted that this shows the leading cam 18 as retracted and so is not according to the invention.
For selective transferring in 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 46 are moved out of the needle bed tricks and engage the cam 40 over the top and bottom needle beds. The butts 46 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 the 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 it on 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 dow. The jacks 42 take no further part and are lowered to some extent by the cam 39 and remains 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 past the height control cam 18 at stage C, past the midway position and reach 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 cams 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 flat 11 holding the delivering needle still between stages G and H. The butts 2 then finally move past the trailing cam 18 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 approach the yarn held on the spreader. The yarn penetrates under the latch and opens it. 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 can 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 lower 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 may be inserted at the positions 70 indicated in Figure 1 and shown in dotted lines in Figure 2.
The mode of operation according to the invention utilising the same cam system as illustrated previously in Figure 1 but with the leading cam 18 projected and trailing one retracted is explained in detail by reference to Figures 3A to 3C.
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 1 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

1. A flat-bed knitting machine of the V-bed type including a transfer system having a transfer cam with raising cam faces defining a loop delivering track for needle operating butts on each side at its upper face and permitting needle operating butts to follow a loop reception track below its lower face to provide loop transfer from either needle bed in either direction of cam carriage traverse characterised in that a retractable cam is provided at the top of each raising cam face which retractable cam is arranged to be projected on the leading side of the transfer cam and to be retracted on the trailing side, the transfer cam having a central portion with flats on either side of a central depression between the retractable cams to locate the loop delivering needles at a suitable level to open the latches of the loop receiving needles after the loops have been spread by lifting the loop delivering needle to a higher level on the retractable cams.

2. A flat-bed knitting machine according to claim 1 in which the retractable cams are each in the form of an elongate cam lying against sides of a central part of the transfer cam so as to form a substantially continuous raising cam face.

3. A flat-bed knitting machine according to claim 1 or claim 2 in which the loop reception track is defined by the lower face of the transfer cam and by further cams arranged to engage butts of jacks for lifting needles indirectly for loop reception.

4. A flat-bed knitting machine according to claim 2 in which the central part of the transfer cam 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 referred to in claim 2 which lie normally against upwardly inclined sides of the retractable upper portion.

5. A flat-bed knitting machine according to claim 4 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.

6. A flat-bed knitting machine according to claim 5 or claim 6 in which retractable cams are provided for guiding needle operating butts to the space between the retractable cams.