Technical Field

The invention concerns the small-diameter knitting machine for automated manufacture of seamless knitted wear, mainly tights, spats, trousers and panties, created by a pair of knitting heads placed one above the other and equipped with knitting needles, sinkers, means for their control, thread guides with a device for cutting and holding the threat ends, drive and electronic control system.

The Contemporary State of the Art

The classic manufacture of knitted wear of the tights type is usually performed using two types of small-diameter knitting machines - single-cylinder or double-cylinder knitting machines. Tights are manufactures on these machines in such a way that two hoses are knitted at the very beginning. These are initially cut in their upper part and then they are sewn together in the tight part. This classic type of tights has a perfect anatomic shape, but it is unfavourable due to the fact that the developed seam is not aesthetical and it breaches the elasticity of the knitted material. In the course of sewing, the sewing needle randomly damages the knitted material and then ladders appear, which depreciates the product.

Mainly due to the above stated reasons, there were developed many knitting machines to replace classic production of tights with seamless products.

One group of these machines is represented by classic single-cylinder small- diameter knitting machines, that were extended in e.g. a device for cutting the tight part, an adjusted device for inter-connection of two trouser legs and the tight part and so on. The common disadvantage of this group of machines was the fact that the tight part was created on half number of knitting needles compared to classic tights and the anatomic shape was not successfully imitated. Due to these reasons, the market gradually refused this group of knitted products.

Another group included knitting machines with two knitting heads axially aligned one above the other, with common pneumatic draw-off device assigned to the bottom knitting head. The whole tights were manufactured by rotation run - in the leg part as well as in the tight part. The tight part was initially knitted on a part of the needle cylinder circumference and then it was cut. Even though the shape of the tights was really close to classic tights, the market did not accept them, as the quality of knitting and cutting of the tight part was of really poor quality and more, it was necessary to carry the tights with the reverse side of the knitted material on the top.

The disadvantages of products from the previous group of knitting machines were eliminated to significant level thanks to the knitting machine with two axially aligned knitting heads and common pneumatic draw-off device assigned to the bottom knitting head - the machine was adjusted to knitting of the tight part by reverse run, without necessity of the tight part cutting. The disadvantages of such a structured knitting machine included mainly its low productivity, caused by the impossibility of placing a standard number of knitting system on the machine, the impossibility of making a patterned product and insufficient fineness of the knitting machine while knitting the tight part of the tights, as half of the knitting needles had to be put out of the knitting process.

There is known even the version of circular knitting machine for creation of tights with the needles organised in a radial bed as well as in an axial cylinder. The needle bed and cylinder are fixed. Revolving lock carriers with mutually contra-rotating elements are placed round them. The lock carriers are equipped with a control device and controllable thread guides. In fact, this knitting machine imitates the activities of flat two-bed knitting machines. The machine was very complicated from the technical point of view and simultaneously, the quality of knitted material - mainly in the leg part - was not accepted mainly due to longitudinal grooves appearing in the whole length of the leg. The machine was not successfully put into the stage of industrial manufacture.

Base of the Invention

The task of the invention is to improve the current state of the art and to create a new type of small-diameter knitting machine, allowing industrial manufacture of seamless knitted wear of hose type, like for example tights, spats, trousers and panties and so on with their anatomic shape and economic character of production to be fully comparable with goods produced on the basis of classic technology using sewing, but that will surpass them in the wearing comfort and aesthetic level due to absence of seams.

Small-diameter knitting machines as per suggested invention reach this, based on the fact that the bottom knitting head and the upper knitting head are adjustable towards each other in at least two mutual working positions and each of the knitting heads is equipped with an independent pneumatic draw-off device.

A significant advantage of such an organised knitting machine is the fact that in a specific stage of the production cycle - for example in the course of legs production - the knitting heads may be re-adjusted in such a way that they work in a completely independent way and the quality of knitted material is not disturbed by mutual negative influences, which occurs in current state of the rt. The number of work systems is not limited in any way by the organisation of the knitting machine, so for example in the course of legs knitting the performance of the knitting machine as per suggested invention nearly reaches the performance of two classic single-cylinder small-diameter machines. Even the pattern-making possibilities of the machine are not limited as the adjustability of knitting heads creates sufficient space for placement of for example classic thread cutting device - for both of the knitting heads. After finishing the legs knitting it is possible to mutually re-adjust the knitting heads in such a way so as it is favourable for the tights knitting - as known for example from the file No. PV 2005-293. The mutual re-adjustability of knitting heads according to the needs of the operation cycle and independent draw-of device for each knitting head reaches the task of the invention.

When the small-diameter knitting machine is organised in such a way that the bottom knitting head is fixed and the upper knitting head is adjustable in relation o the bottom knitting head, it is advantageous mainly for minimisation of adjustable mechanisms.

When the upper knitting head is adjustable by sliding in the direction of the bottom knitting head axis in relation to the bottom knitting head, it is advantageous mainly thanks to the fact that it simplifies the layout of additional mechanisms, like for example thread guides and so on.

It is also advantageous when the upper knitting head is adjustable in a revolving way around the axis that is parallel with the bottom knitting head axis in relation to the bottom knitting head, as it reduces the overall height of the knitting machine construction. If the bottom knitting head and the upper knitting head are axially aligned and in immediate vicinity in at least one work position, the knitting of the tight part is simplified while the construction is simple.

List of Figures in Drawings.

The sample version of the suggested invention is explained in detail using the drawings, when Fig. 1 shows the general view of the knitting machine with mutually displaced knitting heads, Fig. 2 shows a detail of mutually displaced knitting machines, Fig. 3 shows the general view of the knitting machine with knitting heads in immediate vicinity, while Fig. 4 shows a detail of knitting heads in their immediate vicinity.

Sample Version Description

As shown in Fig. 1 , the ample version of the knitting machine consists of the stand 1, housing the base plate 2. The base plate 2 houses the bottom knitting head 3. Below the bottom knitting head 3 it is possible to find the axially aligned driving device 3.7, that may consist e.g. of an electric motor of the brushless type. The driving device 3.7 is followed by an anti-twist 3J5, connected to the draw-off device 3J3, that may consist for example of well-known pneumatic centralised device. The base plate 2 also houses a console 5, with fixed upper knitting head 4. In fact, the upper knitting head 4 is a mirror-image of the bottom knitting head 3, so it is followed by the driving device 4J, anti-twist 4J5 and draw-off device 4J3. The upper knitting head 4 is placed on the console 5 in a sliding way and in this sample version it is adjustable in the direction of the bottom knitting head 3 axis. The mechanism for re-adjustment of the knitting head may be of any known version, for example the endless screw or pneumatic piston. The bottom knitting head 3 and the upper knitting head 4 are shown in Fig. 1 in mutually displaced position, while their position in immediate vicinity is shown in Fig. 3. The individual knitting heads 3, 4 are shown in detail in Fig. 2. The bottom knitting head 3 contains the needle cylinder 3J_, the lock set 3 _^ 2, thread guides 3J3 or the cutting device 3.4. the not-shown knitting needles and sinkers placed in the needle cylinder, the patter- making device, lubrication device and all the other known devices are of standard type, they are insignificant for the new character of the designed knitting machine and that is why they are not described in detail. The upper knitting head 4 is - as already stated - in fact a mirror image of the bottom knitting head 3 and that is why it contains inter alia a similar needle cylinder 4J_, lock set 4,2, thread guides 4J3, cutting device 4,4 and o on. The mutual position of the bottom knitting head 3 and upper knitting head 4, that are axially aligned in immediate vicinity, is shown in Fig. 4. As clearly indicated by Fig. 4, the thread guides 3 _^ 3 of the bottom knitting head 3 are aligned to the upper knitting head 4, thread guides 4J3 are moved away and that is why they are not shown. Fig. 4 shows mutual position of the bottom knitting head 3 and upper knitting head 4 in that stage of the knitting cycle, when the tight part of the product is knitted. Together with the devices shown, the knitting machine is also equipped with other devices like for example the case with electric and electronic equipment, creel, lubrication device and so on, but these are just subordinate for explanation of the new character and that is why they are not displayed in figures.

The mutual adjustability of the bottom and upper knitting heads 3, 4 may be performed even in a different way than as described in the sample version and shown in enclosed figures. In another sample version, the upper knitting head 4 may be readjusted in relation to the bottom knitting head 3 for example by partial turning around the axis which is parallel with the axis of the lower knitting head 3 and passes for example through the console 5. In another sample version for mutual re-adjustment of knitting heads it is possible to combine mutual translocation with mutual partial turning. The variants of mutual re-adjustability performance are functionally equivalent in fact and practical performance always depends on concrete version.

The knitting machine according to proposed invention is designed for knitting of seamless knitted wear like tights, spats, trousers and panties, for example according to file PV 2005-293 and it works as follows:

The product knitting starts with legs knitting in moved-away position of the upper knitting head 4. As the lower knitting head 3 and upper knitting head 4 are moved away from each other and each of them has its independent draw-off device 3J3 and 4j3, the knitting machine as per proposed invention works in this stage of the work cycle in fact as two independent single-cylinder small-diameter knitting machines without any limitation of pattern-making possibilities. After knitting of legs, there are switched off the thread guides 4J3 of the upper knitting head 4 and the knitting head is re-adjusted to the bottom knitting head 3 in such a way so as they are axially aligned and located in immediate vicinity. Consequently, there follows knitting in the tight part by reverse run of the needle cylinders 3J. and 4J. alternatively on upper 4 and bottom knitting head 3, while the newly created knitted material of the tight part is gradually pulled into the hole of the bottom knitting head 3. After knitting the tight part there are switched off the thread guides 3J3, the product is thrown away from the knitting needles in a well-known way and the finished product is drawn off by the draw-off device 3J> of the bottom knitting head 3. In this way, the machine finished its work cycle and it is ready to start knitting of a new product. Industrial Applicability

The invention is designed for knitting of wear - mainly seamless tights.