HOSIERY FINISHING

Abstract: Apparatus for finishing hosiery, preferably coupled to an individual knitting machine (2) includes a means (4, 6) for conveying completed articles to a chamber (10) formed by a sleeve heated by a resistance element (12) contained in the chamber (10). A means for dispensing the heat treated articles (18) permits the articles to be heated simultaneously with the knitting cycle of the next article to effect partial relaxation and shrinkage by actuation through control means (16) operable in step with the knitting machine.

Description: TITLE Hosiery Finishing DESCRIPTION: Field of Invention The invention relates to an apparatus and method for hosiery finishing. The apparatus has a conditioning function and may be retro-fitted onto knitting machines or be incorporated as original equipment. Background of the invention When knitting hose for ladies tights for example, the newly knitted fabric on the knitting machine is pulled down under tension, generally exerted by means of a suction take-down mechanism. When the article is hose is completed, it is pressed off from the knitting machine and a butterfly valve is switched to cause the pressed off article to be conveyed by suction through a U-tube to a dispenser. Λ Upon arrival at the dispenser the article passes through a pivotable trap door and then falls in a bag. The article is next subjected to a finishing procedure. The procedure includes in many cases the placing of a pair of knitted tubes on a Takatori automatic seaming machine where two tubes are slit and the slit portions of adjacent portions linked to provide a single pair of tights with a waistband, a body portion and a pair of leg portions. The article can then be stored and subjected to a dyeing process to meet a particular customer's requirements. During the dyeing process the stockings or tights will shrink because of the attendant treatment in hot water. It is known in the procedure described above, to collect the articles pressed off from the knitting machine and subject them to a tumbling process involving steam so as to ensure that they are shrunk- to a standard length before being subjected to the Takatori linking operation. However even with this refinement it has been difficult to ensure that the articles which are linked together have an equal length and can be placed easily on the machine by the operator. Furthermore the evenness of appearance of the knitted article is sometimes not achieved by the tumbling process and indeed the tumbling process itself can contribute to variations in appearance. Summary of Invention ∑t has been found that significant benefits in finishing procedure can be obtained by subjecting the individual articles to a reproducible relaxation or shrinking treatment in association with individual knitting machines and in synchronisation with individual knitting cycles. Accordingly the invention provides in a first aspect of the invention a knitting machine having ' a suction take-down tube (the term take-down is to be interpreted as including those cases where an article of hosiery is removed from the machine by upward suction) for suction take down of individual knitted articles, and a chamber on the tube having an exit control means for subjecting individual articles propelled by suction to the chamber to a relaxation or shrinking treatment whilst a subsequent article is being knitted on the machine. Looking at the overall procedure of knitting the article i.e. pulling it down by suction to provide take-down tension, and then collecting it for subsequent finishing operations, the invention removes a treatment, tumbling, for which articles had! previously to be collected and stored to be treated in bulk, and replaces it with an individual treatment much earlier in the overal procedure which is integrated with the knitting cycle. The invention may be applied to produce retrofit kits for connecting to existing machines for knitting articles of hosiery. The invention 'can also be applied by installation of the appropriate equipment on the machine as original equipment. Using the invention the shrunk articles collected from the take down tube and chamber can be collected in bags which can be passed directly or which can be stored before further finishing treatments such as seaming together of the legs of a pair of tights on a Takatori machine or for finishing on other forms of equipment. freferably the articles are subjected in the chamber to a treatment such that partial relaxation is achieved. That is to say if the article were subjected to a tumbling treatment it would be able to relax further beyond the stage reached in the chamber. By selecting appropriate conditioning parameters it is possible to produce an article which has a reproducible length and diameter in comparison with subsequent articles knitted on the machine. In other words the variability from article to article can be greatly reduced. At the same time the conditioning treatment can be sufficiently mild to allow the treatment to progress gradually through the article in a knitting cycle in a mildly compacted condition so as to produce an article which has a smooth even stitch structure substantially free of local loop deformation. In further preferred aspects of the invention a simple arrangement is provided for controlling replenishment of the chamber and for permitting the necessary relaxation/shrinkage to be achieved at a low energy consumption. Advantageously the replenishment from the chamber is controlled by a servo-operable barrier which can be moved selectively over the chamber outlet and which is air-permeable to permit the next article to be conveyed by suction into the chamber and against the barrier. Preferably the barrier is moved into the barring position with precise timing subsequent to press-off of the article being knitted so that that article can be caught against the barrier whilst having allowed sufficient time for the previous article treated in the chamber to move out of the chamber and to be optionally collected through a pivotable trap door using the same period of suction air flow. Advantageously also a further barrier can De selectively moved across the inlet of the chamber, which is not air permeable or permeable to a much lesser degree, which can be used to reduce - - or prevent flow of air through the chamber whilst the conditioning treatment is in progress preferably after the article has been blown out through the trap door. Thus a relatively low capacity electrical heating element can be used to obtain a significant degree of heating and shrinkage in the chamber for the period that the articles dwells in the chamber, that is to say the duration of the knitting cycle. Reproducibility from article to article is important and using the equipment previously described it is possible to adjust the heat treatment and duration as appropriate. The chamber is conveniently combined and formed as a continuation of the U-tube of the normal suction take-down mechanism of the knitting machine. The movement of the various barriers can be controlled by reference to the timing mechanism, whether mechanical or electrical in principle, already present on the knitting machine and can be incorporated so as not to interfere with the re-setting of the take-down mechanism required for the normal operation of the suction take-down mechanism. The relaxation or shrinkage treatment is preferably effected by electrical resistance heating but it may be possible to achieve the same objective by other known forms of treatment such as steam treatment, microwave or radio frequency treatment. In a further aspect of the invention there is provided an overall method for finishing a knitted article of hosiery comprising the convention steps of knitting, seaming, and dyeing but which omits the step of tumbling intermediate knitting and seaming and which uses instead the step of heating the individual articles reproducibly on the knitting machine in synchronism with the knitting cycle. By using the invention .it is possible to provide a degree of stretch in waistbands of the leg portions for making up tights which exceeds that available from articles which have been tumbled and which are therefore much more easy to operate on a' Takatori seaming machine. The consistent body length facilitates initial location of the article during seaming and the partial constriction of the width ' of the article by shrinking whilst avoiding the extremes of tumbling, aids in securing the articles on the various forms which may be used in the finishing of hosiery. The fabric structure can be kept smooth and even, avoiding unintentional adhesion of loops which' may occur with more densely folded articles and permitting an even and smooth appearance subsequent to dyeing. DRAWINGS: Figure 1 is a schematic view of a knitting machine incorporating an apparatus for finishing hosiery according to the invention; Figure 2 is a schematic lay-out of the apparatus of Figure 1; Figure 3 is a section through the apparatus of Figure 1 enlarged. Figure 4A-E show successive stages of operation. Description by reference to drawings With reference to the Figures, a knitting machine 2 has a cylinder 3 with needles (not shown) for knitting a tubular article of hosiery for use in making ladies tights or stockings . Conventional parts of the suction take-down mechanism have not been described in detail except insofar as relevant for explaining the invention. A fan 5 is connected to a downward leg 4a of a U-tube 4 through a by-pass 9. The timing of the operation in suction take down is controlled by a butterfly valve 6. At the end of an upward leg 4b of the U-tube 4 there is a trap or dispenser 8 with an internal screen connected to a suction hose 7 to enable the pressed-off article to be sucked to the trap ready for removal through a door 11 and for reception into a boxy or bag 27. The downward leg 4a is connected by the by-pass 9, so that in normal knitting suction can be conveyed in the manner shown in Figure 2 to the knitting cylinder 3 but not to the trap 8 and hence the upward leg 4b. Air is blown to atmosphere from the fan 5 through the valve 6. In pressing off, the valve is switched so that suction flow is conveyed from the trap 8, through the hose 7 to the fan 5. In the process the fan blows its exhaust through by-pass 9 into the downward leg 4a, through the lower section of the U-tube 4 not shown into the upward leg 4b and out through the trap door 11. Dealing now specifically with the invention, an apparatus for finishing hosiery is incorporated into the upright limb of the U-tube using sealing sleeves 31. The apparatus includes at the bottom a pneumatically operated slide 20 for forming a barrier to block flow of air through the tube 4, a chamber formed by a copper sleeve 10 which can be heated by means of a resistance element wrapped around the sleeve shown at 12 and insulated from atmosphere by an insulating sleeve 14. A pair of parallel dispensing control rods 18 controlled by piston -and cylinders devices 16 are provided above the chamber 10 to form a barrier to the knitted article but not to airflow. A piston- and cylinder device 22 controls the slide 20 by means of a rod 23. As can be seen the apparatus is basically very simple in design although various parts can be modified to optimize performance. In operation, asssuming one starts at the stage at which the knitting machine is about to press off an article which has just been knitted, the slide 20 and the dispensing control rods 18 will both be open to provide a free passage to the trap 8 under the control of control system . of the knitting machine 25 (Figure 2) which operates solenoid air valves 27 for the respective piston and cylinder devices. The butterfly valve 6 is (also through the system 25) in the aforementioned condition wherein there is no suction air flow passing through the lower section of the U-tube 4 (Figure 4A) . Next (Figure 4B) the butterfly valve 6 is operated by the system 25 causing air to flow through the lower section of the U-tube 4 and any article held in the chamber one of which is shown at 37 by friction to be blown out and conveyed to the trap 4. As soon as the article has been removed from the chamber, the piston and cylinder devices 16 are operated to project substantially diametrically through the U-tube 4 causing the pressed-off article (shown at 39 in Figure 4C) to be trapped underneath inside the sleeve 10. The resistance elements 12 may be under a constant current for a durration and temperature controllable by the system 25 and tend to heat the contents of the chamber although the continuing flow of air at this stage tends to reduce the temperature which can be achieved. Alternatively a control arrangement 29 may be provided to ensure that a consistent temperature is maintained. Next as the knitting machine reaches the stage where the welt is turned, the valve 6 may again be operated to establish the normal suction take-down condition for knitting and a piston and cylinder device 22 is operated through rod 23 to shift the slide 20 across the U-tube 4 (Figure 4D) . As a result air can no longer pass through the tube 4 and the air in the sleeve 10 will now gradually heat up and rise by convection (see the dashed arrows) through the article held in mildly folded condition underneath the rods 18 which now can be withdrawn (Figure 4E) . At the end of the heating cycle the slide 20 is withdrawn. The cycle can then be repeated. Typically the heating process lasts for a period of two minutes (concurrently with the knitting cycle) and leads to a temperature of something in the region of 85°C or to 120°C for shorter knitting cycles. Preferaby the duration of heating is matched to that of the knitting cycle so that the introduction of the newly pressed-off article into the sleeve 10 can be achieved at the same time by the well timed introduction of the rods 18. The U-tube arrangement is such that there is a gap betwen .the old (shrunk) article and the new (pressed off) article which permits the rods 18 to be introduced without catching an article. Because there is no flow of air through the chamber 10, the heating effect desired can be achieved with a fairly low current consumption. W hilst the article is folded inside the chamber it is not crumped closely together and the gradual heating, mainly by convection, causes even shrinking of the article wit h out the formation of excessive creases which could have a permanent effect on the appearance of the finished article. The heating con d itions should be selected such that a smooth f abric finish is obtained and parts of the fabric do not adhere to one another. In the fully projected condition the rods 18 only stretch across part of the way of the tube 4 (see Figure 3) so that there is no opportunity for the fabric to become trapped and damaged by the rods in the course of operation. The rods 18 are withdrawn through tight holes so as to prevent any damage to the fabric on their withdrawal. The invention could be modified by modifying the heating arrangement, for example by using a ceramic sleeve and/or by introducing a degree of agitation into the chamber for ensuring and aiding the even spread of heat through the article. It is to be noted that the duration of heating and the variation of temperature can be varied as required in step with the production of knitted article on the knitting machine in a convenient manner. Full control " over the processing conditions can thus be achieved so as to give an optimal effect. Considerable stretch characteristics can be imparted whilst at the same time reducing the size variations from one article to the next. The relaxation and shrinkage achieved is relatively mild compared with that achievable by tumbling yet a superior article can be surprisingly obtained together with the advantages of easier manipulation of the articles during any seaming operation for making tights. The apparatus can be retrofitted onto existing machines and ■requires little or no additional space whilst avoiding the 'handling and storage requirements attendant upon the use of the tumbling, process. The gentle reproducible heating treatment of the knitted article immediately after knitting thus provides advantages in finishing compared with the more laborious previous finishing procedure which incorporated tumbling.

Claims: CLAIMS : 1. Apparatus for finishing hosiery articles including: a chamber adapted for causing relaxation of articles in it; means for connecting the chamber to a suction take-down tube of a knitting machine for receiving articles from the knitting machine; means for controlling the exit of articles from the chamber actuatable in synchronisation with a knitting cycle on the knitting machine. 2. An apparatus according to claim 1 in which there is provided means at either end of the chamber for securing at an intermediate position to a suction take-down tube of a knitting machine. 3. An apparatus according .to claim 2 in which the chamber is generally upright and a continuation of the tube and of similar cross section. 4. An apparatus according to any of the preceding claims in which the chamber is heated by an electrical resistance element to effect relaxation. 5. An apparatus according to any of the preceding claims in which the means for controlling the exit of articles includes a barrier to prevent an article leaving the chamber by air flow, which barrier may be withdrawn to permit the article to exit.. 6. An apparatus according to claim 5 in which the barrier is air permable to permit flow of air from the chamber by convection. 7. An apparatus according to any of the preceding claims in which a further barrier is provided for resisting air flow into the chamber during relaxation which is withdrawable to permit a new article to enter the chamber. 8. A procedure for finishing hosiery articles including heating articles to effect partial relaxation individually after press-off from a knitting machine before collection together in a container, seaming the leg portions together in an undyed condition without a preliminary additional shrinking step (e.g. tumbling) ; dyeing the seamed article to provide a completed fully relaxed article. 9. An apparatus for finishing hosiery articles substantially as described with reference to and as shown in the Figures. 10. A knitting machine having a suction take-down tube for suction take down of individual knitted articles, and a chamber on the tube having an exit control means for subjecting individual articles propelled by suction to the chamber to a relaxation or shrinking treatment whilst a subsequent article is being knitted on the machine.

Inventors: MOSS STANLEY HARROP, MOSS, STANLEY, HARROP
Applicants: ADRIA LIMITED
Application year: 1988
Main classification: D04B35
IPC codes: D04B35