US2449105A - Yarn take-up - Google Patents

Description

Sept 14, 1948. .1. s. BRADLEY ETAL 2,449,105

YARN TAKE-UP Filed May 25; 1947 YVES/T055.'

EHA/BRAMEX MfmqA/ESMIT Y TTY LN Patented Sept. 14, 1948 YARN TAKE-UP John S. Bradley, North Attleboro, Mass., and Norman H.' Smith, Pawtucket, R. I., assignors to Hemphill Company, Central Falls, R. I., a corporation of MassachusettsV Application May 23, 1947, Serial No. 750,098

(Cl. Gti-146) 6 Claims.

This invention relates to a nev.r and useful improvement in yarn take-ups such as are used kon knitting machines of the circular, independent needle type. Take-up mechanisms of the same general type are not new. One is disclosed in Patent #2,193,311. The particular advantage of this invention resides primarily in a different take-up spring through which the effective tension is varied and the take-up is adapted to the exacting requirements of fine gauge knitting such as the knitting of sheer ladies stockings.

One form of the invention, designed for a circular, independent needle, knitting machine of the Banner type, is shown in the drawing of which:

Fig. 1 is a side elevation of a pair of take-ups and their controlling mechanism; and

Fig. 2 is a plan View of similar scope.

As many take-ups as desired may be used. They may be identical. Two are shown in the drawing, one in inoperative and one in operative position.

As shown in Fig. 1 the take-up consists of the usual light wire arm I, identical with the similar arm 2 of the other take-up, the free end of which is bent down and terminates in a yarn guiding loop similar to loop 3 of the other take-up and through which the yarn passes on its way from the cone to the yarn lever.

The other end of arm I is fixed in a block 4 pivotecl on a horizontal shaft 5. In the form shown block 4 is slotted as at 6 so that the takeup arm I can be slid into it sideways after which it is iixed in position by set screw 'I. Extending rearwardly of block 4 is a tail 8 which may be integral with arm I. This tail is offset laterally of arm I as best shown in Fig. 2. Below tail 8 is a spring arm 9 which is substantially flat, one end of which has an opening I9 therein through which tail 8 passes.

On the frame II of the take-up is pivoted, as at I2, a rocker I3 to which the spring 9 is secured by a cover plate I4, which is held by screws I5 to bind the spring between the cover and the rocker. Therefore, the spring 9 is pivotable on the frame at I2 with the pivotal movement preferably in a vertical plane and limited in the up direction by an adjustable set screw I6 mounted in a bracket Il and in the down direction through the holding action of the yarn exerted through the arm I.

Normally, the downward pull of the spring 9 causes the tail 8 to be pulled down, pivoting the arm I upward against the resistance of the yarn. In so doing, the foot end of spring 9 slides along tail 8. In this way, the effective length of tail 3` with respect to shaft 5, upon which the take-up arm I is pivoted, is varied which results in automatic changes of leverage.

As the spring moves downwardly, its effective strength becomes progressively less, but its longitudinal leverage on the tail 8 allows this decreasing spring strength to exert a substantially constant or increasing force upon the arm I. The spring 9 is sufliciently rigid lengthwise so that as the arm I is swung about the pivot 5 through the tightening or loosening of the yarn, the foot of the spring 9 moves along the tail 8 to provide the desired leverage Variation. This lengthwiseV rigidity is important in that it provides positive and smoothly progressive movement of the spring along the tail 8, and leverage changes are made smoothly.

Byaltering the 'curvature or shape of tail. 8, the effect of the spring 9 can be additionally adjusted so that changes in the rate or character of leverage variation may be suited to requirements.

Further variations in adjustment are possible through the elongated screw openings Il in the spring 9. The screws I5 may be loosened and the spring 9 adjusted lengthwise within the limits dened by the openings Il and the screws I5 therein. Also, the pivot shaft I2 may be adjusted in the body I I by means of the elongated opening I8 in the frame. The pivot shaft I2 eX- tends through this frame opening and is secured by nut I9 on the end of the shaft I2 after it has been adjusted toward or away from the the pivot 5 of arm l.

Thus the eiective length of the spring 9, its effective strength and the adjusted position of the spring opening ID with respect to tail 8 may be Varied, as desired, within the limits of the adjustments set forth above, using these adjustments either singly or in combination to get the desired spring position, effective strength and leverage relation.

The spring 9 is an L-shaped fiat spring member with the top of the L secured to the rocker I3 and the foot of the L having an opening ID therein. The spring 9 resists the downward swinging action of arm I as it is pulled down by the yarn. In association with take-up arm 2, the second flat spring 20 is shown (Fig. 1) in up-sprung position and exerting its strongest inherent downward pull. In the drawing, the position of spring 9 indicates a minmum of downward pull since the spring lies unilexed. Springs 9 and 20 are identical in form and operation and are shown in different positions for purposes of illustration.

Suitable devices for making the take-up inoperative when desired, and for clamping the yarn to prevent excess feeding from the cone, may be used with the take-up assembly of this invention. In former .take-ups the spring had to be strong enough to lift the `take-up arrnA quickly to its highest position, say 60 degrees or more above the horizontal. arm moved down the tension of the spring increased constantly and unavoidably became too great within the working rangeof theiake-up while knitting was being carried on.

When knitting extremelynsheer fabrio such-as;

a ladys stocking, very small errors in method, particularly those affecting v.the.yarn, vproduce very noticeable fabric defects. It has been found that the tensioning effect of spring 9 upontakeup arm l should be substantially uniform throughout the movements of the take-up and, in some instances, should be lighter .when ythe take-up is down .than when it is raisedso .that the take-up will exert a negligible .or minimum effect upon the yarn duringknitting.

Often it is desirable that the liftingeffect of spring Supon arm i should increase as .thearm rises in spite of the decreasing actual tension of .the spring. All .of these things "can be accomplis'ned vby the hook-up described above through the proper shaping and proportioning ofarm l, tail 8 and spring 9. Since an infinite variety of conditions are met in the knitting of various fabrics these matters must and can beleft for determination by those skilled in the art. The manner in which a take-up of this character operates is otherwise too well-knoWn-'to `require further description.

The springs 9 and 20 are described aslat, :and

it is int-ended that this .shall mean. leaf 'type' springs, and that a resilient rod '.or wire shall come Within the scope of this vdefinition and invention.

We claim:

l. A yarn take-up for a knitting :machine which includes a swingable take-:up armand a leaf spring member for swinging said. arm, A'said spring comprising a source of energy which is greatest when said arm .is downV and which decreases progressively as said `arm rises, said yspring As a result, when the take-11p having an end thereof in variable leverage relation with said arm, whereby variations in the applied force of said spring are accompanied by simultaneous inverse variations in its effective force upon said take-up arm.

2. In a knitting machine, a pivoted yarn takeup arm, a tail member for said arm, and a leaf spring associated with said tail in variable leverage relation therewith, whereby variations in the .applied force of said spring are accompanied by simultaneous inverse variations in its effective "forcelupon said take-up arrn.

3. :In aknitting machine, a pivoted yarn take- .up arm, a tail member for said arm, and a leaf spring having one end pivoted and the other riding on said tail in varying leverage relation therewith. to counteract varying forces in said v-spring.

.4.` In a knitting machine, a pivoted yarn takeup arm, a tail member for said arm, a leaf spring having one end pivoted and the other riding .onsaid tail in varying leverage relation therewith to counteract varying forces in said spring, and means for adjusting the pivot of said spring to change its distance from said take-up arm pivot.

f 5. A yarn take-up for a knitting machine which includes a pivoted take-up arm, a tail member for .said arm, a leaf spring riding on .said tail in varying leverage relation therewith to counteract varying forces in said spring, and means for changing, by adjustment, the effectivelength of said spring.

6. In a knitting machine, a pivoted take-up arm, a tail member for said arm, a leaf spring .having one end pivoted and the other riding on said tail in varying leverage relation therewith to counteract varying forces in said spring, and an adjustable stop for limiting the pivotal Amovement of said spring.

JOHN S. BRADLEY. NORMAN H. SMITH.

' le of this patent:

UNTED STATES PATENTS Name Date St. Pierre June 1'7, 1947 Number

Images