Title:
TAPE-POSITIVE YARN FEED
United States Patent 3855821


Abstract:
Yarn feeding device for multifeed circular knitting machines, comprising a system of rotatably mounted feed rollers mounted around the knitting machine, said rollers being surrounded by a continuous feeding belt driven from a driving pulley. Each of said feed rollers is attached to one knitting feed and being provided with guiding eyelets. An auxiliary roller is associated with each feeding roller with each pair of said rollers surrounded by a separate feeding belt, which is in engagement with the continuous feeding belt with this arrangement an improved yarn nip is achieved with the yarn passing through the guiding eyelets and between the continuous feeding belt and the separate feeding belt.



Inventors:
STERBA J
Application Number:
05/323773
Publication Date:
12/24/1974
Filing Date:
01/15/1973
Assignee:
VYZKUMNY A VYVOJORY USTAV ZAVODY VSEOBECNEHO STROJIRENSTVI,CS
Primary Class:
International Classes:
D04B15/48; (IPC1-7): D04B15/48
Field of Search:
226/172 57
View Patent Images:
US Patent References:



Primary Examiner:
Feldbaum, Ronald
Claims:
What is claimed is

1. In a multifeed circular knitting machine having a cylinder, a yarn feeding device for feeding a plurality of yarns thereto, said device comprising a plurality of pairs of rotatably mounted idle feeding rollers and auxiliary rollers in angularly spaced relationship around the knitting machine, the feeding rollers being disposed generally in a circle coaxial of the cylinder of the machine, each of the auxiliary rollers being disposed radially inwardly of the feeding roller of its pair with respect to the said cylinder, each pair of a feeding roller and its auxiliary roller being joined by its individual separate feeding belt, each pair of rollers being fitted with an entrance guiding eyelet and a delivery guiding eyelet, all the separate feeding belts being on the radially outer surfaces of the feeding rollers in driving engagement with a continuous driving and feeding belt extending around the machine and around the feeding rollers thereof and receiving a uniform driving motion from a drive mechanism, the guiding eyelets guiding the individual yarns between the places of contact of the continuous driving and feeding belt with the respective separate feeding belts on the feeding rollers and their auxiliary rollers.

2. The combination according to claim 1, comprising a plurality of holders angularly space around the cylinder of the machine, each pair of feeding and auxiliary rollers being journalled on a respective holder, and means for adjusting each holder with its pair of rollers and the feeding belt entrained thereover radially of the cylinder of the machine.

Description:
The present invention relates to a device for the constant feeding of yarn into the knitting feeds of multifeed circular knitting machines.

A device known hitherto for the constant feeding of yarn consists of a system of rotatable feeding rollers arranged about the circumference of a circular knitting machine, said rollers being surrounded by a continuous feeding belt which is driven by a controllable drive. The feeding of yarn into the knitting feeds is performed by its positioning between said continuous feeding belt and said feeding rollers, between which the yarn is guided by means of guiding eyelets.

This device operates reliably, however, only when feeding high quality yarns. With yarns of inferior quality, in which breakage takes place more frequently, the yarn becomes wound around the feeding rollers and must be removed therefrom, whereupon the efficiency of the knitting machine is reduced.

A further disadvantage of such prior device consists in the considerable wear of the feeding belt due to friction of yarn fed by it, whereby the accuracy of the yarn feeding velocity is diminished. The feeding at constant speed of yarns made from synthetic fibers is therefore practically impossible.

Furthermore, another feeding device for circular knitting machines is known in which the system of feeding rollers is surrounded by two juxtaposed continuous feeding belts driven by a controllable drive. The inner feeding belt is guided apart from the driving point by the neighboring guiding rollers over tensioning rollers, while the outer feeding belt is guided only over the guiding rollers. Feeding of yarn is performed between such two feeding belts, which move parallel to each other.

The disadvantage of this last arrangement consists in the considerable length of the inner feeding belt, whereupon a partial delay in feeding is caused at feeding points remote from the drive, due to the resiliency of said belt, particularly upon starting the machine. As a result, the quality of feeding, as well as the quality of the knitwork produced is inferior.

The last arrangement also requires a more frequent change of the inner feeding belt, which is very difficult, as the belt must be slipped over the creel and the threading of yarns into the appurtenant knitting feeds has to be interrupted.

A further disadvantage in that dirt and other impurities which are deposited from the yarns on the inner feeding belt are transferred to the tensioning rollers and must be mechanically removed. Even that reduces the efficiency of the machine.

The said disadvantages are mitigated by the present invention. In accordance with a preferred embodiment of the invention an auxiliary roller is attached to each guiding roller, and a separate feeding belt surrounds each said two rollers, said feeding belt being in engagement with a continuous feeding roller which is driven by a controllable driving mechanism mounted thereon within the general outline of the machine.

The advantage of the feeding device according to the present invention consists in that it can be applied successfully even for feeding yarns of inferior quality, as the broken yarns can not be wound around the guiding rollers. The feeding of synthetic yarns is carried out with a substantially lower rate of wear of the feeding belts.

A further advantage of the invention is that, in view of the short length of the separate feeding belts, the yarn is fed evenly into all knitting feeds even upon the starting or stopping of the machine, thus improving the quality of the knitwork produced.

A further advantage of the invention is the easy changing of the separate feeding belts in the case of damage thereto.

A further important advantage is that the separate feeding belts engage the auxiliary rollers only on their reverse sides, which do not engage the being fed yarn, and thus said rollers are not directly polluted or made dirty by the yarn.

The single FIGURE of the drawing shows an exemplary embodiment of the feeding device according to the present invention, the view being partial diagrammatic view in plan of the feeding device in association with a circular knitting machine. The axes of the rollers 4 and 5 are located in a plane disposed parallel to the length of holder 3; thus such plane is also disposed radial of the cylinder of the circular knitting machine 1. The parallel runs of the belts 6 are thus disposed radially of such cylinder and of the outer belt 11.

Around a fragmentarily shown conventional knitting machine 1 there is mounted on a frame 2 a system of angularly spaced holders 3 in an arrangement radial of the cylinder of machine 1. To each of holders 3 there is fastened a pair of rollers, one of the pair being a feeding roller 4 and the other an outer auxiliary roller 5. The latter is mounted on a holder 3 and is freely rotatable and radially adjustable in the direction towards the center of the cylinder of the knitting machine 1, while the guiding roller 4 is mounted for rotation about a fixed axis. The two rollers 4 and 5 of each pair are surrounded by a separate feeding belt 6. On frame 2 there is mounted a controllable driving mechanism 7 having a driving roller 8 which drives the continuous feeding belt 11 at a constant speed. A pair of idle holding rollers 9, mounted rotatably on a bracket 10, is attached to the driving mechanism 7, said bracket being fastened e.g., to said driving mechanism. Around the whole system of guiding rollers 4 there is arranged a continuous belt 11, which is in contact with each separate feeding belt 5 at each guiding roller 4, the belt 11 partially passing about the holding rollers 9 in the proximity of driving mechanism 7. In the section between the two holding rollers 9, said belt 11 is partially wound about the driving roller 8. To each holder 3 there is fastened a pair of guiding eyelets 12 for guiding the yarn (not shown) which is fed between the continuous feeding belt 11 and the separate feeding belts 6.

Upon starting the operation of the circular knitting machine 1, the driving roller 8 of the controllable driving mechanism 7 begins to rotate, thus imparting motion to the continuous feeding belt 11. Due to friction between belt 11 and belts 6, the separate feeding belts 6 are simultaneously set into movement, whereupon constant feeding of the yarn (not shown) is performed. It will be understood that said yarn passes through one of the guiding eyelets 12, between the continuous feeding belt 11 and the separate feeding belts 6 from a creel (not shown) through the other eyelet 12, and to the knitting feeds (not shown) of the circular knitting machine 1.

The present invention can be applied in all types of circular multifeed knitting machines, in which feeding of yarn at a constant rate is desired.

Although the invention is illustrated and described with reference to one preferred embodiment thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a preferred embodiment, but is capable of numerous modifications within the scope of the appended claims.