Patent Publication Number: US-RE30557-E

Title: Yarn binder apparatus

Description:
BACKGROUND, BRIEF SUMMARY AND OBJECTS OF THE INVENTION 
     This invention relates generally to yarn holding devices and more particularly to binders for holding elastomeric yarns in circular knitting machines. 
     In the knitting of garments, it is common practice to employ a plurality of yarns, elastic and/or inelastic, which are introduced to and removed from the knitting operation selectively according to a predetermined pattern to achieve the desired knitted fabric for the garments. Feed fingers are provided at various yarn feed stations to introduce and remove yarns from the knitting position, as required. When a given yarn is removed, it is severed in a conventional manner, and the free end retained by a holding device so that the yarn will be available for reintroduction to the needles. 
     Elastomeric yarns currently are in wide use in the production of garments by circular knitting machines. Normally these yarns must be knit under tensions of up to five grams. When the elastomeric yarns are not in use during the garment knitting cycle they must be retained in a ready position for subsequent reintroduction to the machine needles. 
     Clamps upon knitting machines for holding the free ends of yarns are old and well known. For example, U.S. Pat. No. 3,164,975 discloses the use of leaf springs for clamping threads to a dial cap. Such holding means have been generally satisfactory for inelastic yarns. However, they have been unsatisfactory in knitting elastomeric yarns due to the retractive forces of such yarns, causing them to withdraw from the restraining action of the clamps. This results in the elastomeric yarns having to be rethreaded manually in the machine. 
     The use of positively displaceable yarn clamps for elastic yarns are well known, for example, as disclosed by U.S. Pat. No. 3,379,036. While the holding action of such positively displaceable clamping means has been generally satisfactory, they must depend upon and must operate in timed relation with various components of the knitting machine, such as the main pattern drum or other sequence regulating devices. 
     The yarn binder of the present invention includes a metallic member attached to a support mounted upon the dial cap of a conventional knitting machine. The dial cap defines an opening permitting a free edge of the metallic member to rest upon, with a slight pressure, the dial plate or pad. The member is angularly disposed relative to the dial plate such that as a finger-feeding elastic yarn is withdrawn, the end of the elastic yarn is pulled across the dial plate and wedges itself between the metallic member and the flat surface of the dial pad. The yarn is severed, and the end retracts trapping itself at the wedge point until it is to be reintroduced to the needles. 
     One of the primary objects of the invention is the provision of a new and improved yarn binder for elastomeric yarns. 
     Another object of the invention is the provision of a binder for elastomeric yarns which operates automatically independent of various machine operational components. 
     A further object of the invention is the provision of a new and improved yarn binder which is of simple, economical construction and which locks or grips the elastomeric yarn when in the non-feed position and which permits the yarn to be conveniently released when yarn is again introduced to the needles. 
     Still another object of the invention is a self-cleaning yarn binder which is of durable construction, reduces yarn waste and eliminates wear on the yarn. 
     Other objects and advantages of the invention will become apparent when considered in view of the following detailed description of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fragmentary perspective view of one embodiment of the yarn binder of the present invention illustrating the binder holding an elastomeric yarn; 
     FIG. 2 is a schematic, top-plan view of a dial cap and a dial plate for a circular knitting machine illustrating the positioning thereon of yarn binders of the present invention; 
     FIG. 3 is a schematic, fragmentary side elevational view of a dial cap and dial plate in relation of the needle cylinder and needles and illustrating the yarn binder of the present invention; 
     FIG. 4 is an enlarged fragmentary view of a dial plate and a binder element illustrating the biting and wedging action upon an elastomeric yarn; 
     FIGS. 5-7 illustrate the path of the elastomeric yarn when reintroducing the yarn to the needles and self-clearing of the yarn from the binder; 
     FIG. 8 illustrates the path of the elastomeric yarn when the yarn is positioned between the binder and the dial plate prior to severing of the yarn from the knitted fabric; 
     FIG. 9 is a fragmentary schematic, side elevational view of the binder and dial pad with elastomeric yarn held in a non-feed position by a feed finder; 
     FIG. 10 is a view similar to FIG. 9 with the yarn being held in a feed position by the feed finger for introduction to the needle; and 
     FIGS. 11A-11E are enlarged, fragmentary views of the dial plate and the binder element illustrating the deflection of the lower end of the binder element as yarn is introduced to and removed therefrom. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawing, and particularly to FIG. 1, reference numeral 20 designates a dial cap and numeral 22 designates a dial pad or plate of a conventional circular knitting machine. The dial cap may be of a conventional type having a hub 24 and vacuum tubes 26. 
     The dial cap 20 is provided with generally triangular shaped openings 28 as will be subsequently described. Conventional dial cap constructions may have portions cut or otherwise removed therefrom to form the openings 28. 
     The yarn binder 30 of this invention is conveniently mounted upon the dial cap 20 of a circular knitting machine. The binder 30, as illustrated, consists of an elongated, metallic member 38 having one end secured to a bracket 32 by releasable fastener 36. The bracket is secured to the dial cap 20 by a releasable fastener 34. The bracket 32 includes first and second sections 40, 42 angularly disposed relative to each other. 
     The metallic member 38 is secured adjacent one end 37 to the bracket 32 by fastener 36, while the opposite blade-like edge rests upon the upper flat surface 44 of the dial pad 22 exposed by an opening 28. 
     In the embodiment illustrated, the metallic member 38 is of spring steel construction having a width of approximately two centimeters. The spring member 38 extends downwardly from the fastener 36 at a relatively steep angle X as shown by FIGS. 1, 3 and 4, with a flat end or edge 46 in contact with dial plate surface 44. While the angle X, FIG. 4, approaches 90°, the flat end 46 of the blade-like member 38 is downstream of the upper fixed end 37, in the direction of yarn travel. 
     Angularly positioning the member 38 in this manner permits the end 46 to deflect to the right, FIG. 4, releasing elastomeric yarn E as it is pulled to the right. As the yarn E moves under the end 46 and the yarn subsequently severed, in a conventional manner by blade 45, FIG. 8, the retractive forces in the yarn towards the left in FIG. 4, tend to displace the end 46 of member 38 to the left further wedging or biting into the yarn E between the end 46 and the flat surface 44 of dial pad 22. FIGS. 11A-11E illustrate deflections of the outer end 46 of element 38, as yarn E is positioned thereunder, the end severed, and the yarn again reintroduced to the machine needles. 
     The sequence of operation of the yarn binder upon a knitting machine is shown by FIGS. 5-8. In FIG. 5 the elastomeric yarn E extends from a supply source, not shown, through a yarn feed finger 50 and is bound between flat surface 44 of dial pad 22 and the lower displaceable edge of the binder element 38. The feed finger 50 is in a raised position and the yarn E passes over the needles 52, FIG. 9. Referring to FIG. 6, when the yarn E is to be reintroduced into the knitting operation, the feed finger 50 is pivoted downwardly in a conventional manner to the FIG. 10 position such that the yarn enters the needles 52 at feed station F. FIG. 7 illustrates the self-clearing action of the yarn binder as the needles move counterclockwise to pull the severed yarn end ES from under the binder element 38. 
     When the elastomeric yarn is to be removed from the knitting position, the yarn feed finger 50 lifts the yarn at station F, FIGS. 8 and 9, to a position above the needles in a known manner, and the yarn E slides across the flat surface 44, defining a chord across the plate 22, and under the element 38 as the needles 52 move about the cylinder 54. Subsequently, the yarn is severed in a conventional manner from the knit fabric and the yarn again clamped by the element 38 to surface 44. 
     Thus it can be seen that the yarn binder is extremely simple in both construction and operation. While the element 38 may be of various selected dimensions, configurations and construction, it is essential that the lower end portion be capable of displacement or deflection to readily permit removal of the yarn, introduction of the yarn and a gripping, wedging or biting action upon the yarn due to the retractive forces in the yarn after severing of such yarn. 
     While one yarn binder has been described, it is to be understood that a plurality of binders may be provided upon a single dial cap.