US3228213A

US3228213A - Yarn trimmer for circular knitting machines

Info

Publication number: US3228213A
Application number: US263767A
Authority: US
Inventors: Grady W Wilson
Original assignee: GORDONSHIRE KNITTING MILLS Inc
Current assignee: GORDONSHIRE KNITTING MILLS Inc
Priority date: 1963-03-08
Filing date: 1963-03-08
Publication date: 1966-01-11
Anticipated expiration: 1983-01-11

Description

Jan. 11, 1966 G. w. WILSON 3,228,213

YARN TRIMMER FOR CIRCULAR KNITTING MACHINES Filed March 8, 1963 2 Sheets-Sheet l nnumun WW1mmIii 50 FIG. 2

Q H :s f" *1 94 92 86 92 8O 84 24 \\ill\lillllllllII G as Q 84 m N 80 BY ATTORN EYS Jan. 11, 1966 G. w. WILSON YARN TRIMMER FOR CIRCULAR KNITTING MACHINES 2 Sheets-Sheet 2 Filed March 8, 1965 INVENTOR. GRADY W. WILSON MWYMA'MCMM Fl G. 6

ATTORNEYS United States Patent 3,228,213 YARN TRIMMER FOR CIRCULAR KNITTING MACHINES Grady W. Wilson, Cayey, Inerto Rico, assignor to Gordonshire Knitting Mills, Inc., Cayey, Puerto Rico, a

corporation of Pnerto Rico Filed Mar. 8, 1963, Ser. No. 263,767 7 Claims. (Cl. 66-145) This invention relates to automatic yarn trimming mechanism for use in a circular knitting machine having one or more yarn-feeding stations. When in a knitting operation a yarn is introduced or taken out, a loose end is left which must be trimmed off before the article is ready for sale. In the past this has usually been done by hand. More recently mechanisms have been devised for trimming the yarn ends automatically by mechanism incorporated in the knitting machine. It is an object of the invention to provide yarn-clipping and yarn-handling apparatus in a circular knitting machine equipped for yarn changing, which is simpler and more reliable than devices heretofore provided for the same purposes. Other advantageous features will be recognized in the following description of the invention and on the drawings, of which FIGURE 1 is a perspective view of parts of a circular knitting machine on which an embodiment of the invention has been installed;

FIGURE 2 is a fragmentary perspective view from another angle and on a larger scale, of some of the mech anism shown in FIGURE 1;

FIGURE 3 is a section on the line 33 of FIGURE 1;

FIGURE 4 is an enlarged perspective view of the shear block shown in FIGURES l and 2;

FIGURE 5 is a plan view of the mechanism shown in FIGURE 1; and

FIGURE 6 is an enlarged fragmentary perspective view of parts shown in FIGURE 2.

The devices hereinafter described are shown on the drawings as attached to a circular knitting machine of the type illustrated in Patent No. 1,641,101, granted to Scott on August 30, 1927. The machine has a complement of latch needles 24) arranged around a stationary disk 22 which may be a dial cam cap, the needles being for convenience indicated without heads in FIGURE 1. A ring 24 having teeth on its periphery is rotated in unison with the cylinder which carries the needles 20. The teeth on the ring 24 are of the hand-saw variety with the cutting edges preferably inclined forward in the direction of motion. The machine may have one or more yarn-feeding stations, one such station 26 being indicated in FIGURE 1, two

such stations

26, 28 being indicated in FIGURE 5. Each station may have several feeding fingers, two

such fingers

30, 32 being shown at the main station 26, two

fingers

34, 36 being shown at the auxiliary station 28. When a feeding finger at the main station, such as the finger 30, is lifted out of action, the last needle to take the yarn 38 therefrom carries it around the cylinder to a shear block 40 which is stationary and bears on a portion of the ring 24. During this travel of the last needle to take the yarn, it draws yarn from the elevated finger 30, the portion of the yarn 38 between the finger and the needle being carried by the movement of the needle under a main yarn guide 42 which is mounted on the disk 22, against a vertical guide post 44, under an auxiliary yarn guide 46 and under an air block 50. The air block 50, as shown in FIGURE 3, has a vertical bore 52 therethrough. The lower end portion 54 of this bore is of smaller diameter than the upper portion, a conical shoulder 56 being between these portions. A ball 60 is seated on the shoulder 56, this ball having a diameter less than that of the upper portion of the bore 52 so that suction created in the bore sufiicient to lift the ball draws air in through the orifice at the lower end of the bore. The block 50 is mounted on the disk 22 but part of the lower portion is cut away to provide clearance 62 beneath the bore 52. When the idle yarn 38 is drawn past the block 50 it is pulled under the block against a small guide pin 64 in the clearance 62 which ensures that the yarn extends directly under the bore 52. The upper end of the bore is conveniently closed by a screw plug 66. At certain periods during the operation of the machine, air under pressure is supplied to the block 50 from any suitable source (not shown) through a supply pipe 63 and a horizontal nozzle which directs the air stream across the upper part of the bore 52 into an exhaust pipe 72. The latter leads to a screened basket '74 in which hits of yarn sucked into the bore 52 can be collected for disposal.

The jet of air across the bore 52 lowers the air pressure in the bore and the resulting suction lifts the ball 60 and draws air into the bore. If any loose yarn is in the clearance 62 beneath the block 50, it is sucked up into the bore. When the air jet is shut off, the ball falls to its seat 56 and clamps any yarn or yarns which may then be extending through the orifice at the lower end of the bore 52.

As the yarn 38 is carried around by a needle, the portion next to the needle passes between two of the teeth of the ring 24. When this reaches the shear block 40, the teeth pass under the forward cutting edge 76 of the block and the resulting shearing action severs the yarn at that point, very close to the last needle to take the yarn. The free end of the idle yarn 38 is at once sucked into the bore 52.

The shear block 40 is illustrated in FIGURE 4. It consists of an elongated rectangular block of steel having a very hard inset 80 at the forward end of the bottom of the block. The lower front edge 76 of the inset 80 is the cutting edge which cooperates with the teeth of the ring 24 to clip the yarns that are carried around by the teeth. The sides of this edge 76 preferably make an acute angle. The inset 80 is of very hard material such as carbide steel or tungsten carbide. At the other end of the block is another inset 84 of the same material as the inset 80 to act as a wear piece. These insets result in long service by the shear block without resharpening or replacement. On the top surface of the block 49 is a central protuberance 86 on which presses a leaf spring 88 an end of which is secured to the disk 22. Two headed screws 90 pass loosely through the other end portion of the spring 88 and are threaded into holes 92 in the top of the block 40, these holes being on opposite sides of the protuberance 86. The block is thus held loosely under the spring 88 which presses on the central protuberance. This floating connection allows the insets 82, S4 to press evenly on the ring 24.

A trigger for a stop-motion device is provided on the dial cam cap 22. This comprises two

resilient leaf springs

94, 96 mounted on a block 98 of insulation and connected to a wire 100 which leads to a source of electrical energy (not shown) which is grounded as usual. If a yarn carried around to the shear block 50 fails to be severed thereby and is drawn in behind it, the yarn will press the leaf spring 94 into contact with a grounded metal part of the machine, thus closing a circuit to energize a stop-motion mechanism (not shown). If a needle becomes bent, it may catch on the shear block 40 and raise it so that one of the screws 90 touches the spring 96 and closes the stop- 0 motion circuit.

I claim: 1. In a circular knitting machine having a circular series of needles and equipped for yarn changing, means for handling the yarns when changes are made, said means comprising a plate surrounded by said needles, a block mounted on said plate, said block having a vertical bore extending upward from the bottom thereof and a clearance between a portion of the bottom and said plate communicating with said bore, tube connections with the upper part of said bore for creating suction therein, the lower portion of said bore being of smaller diameter than the upper portion thereof, a ball in said upper portion having a diameter slightly larger than that of said lower portion of the bore and adapted to be raised by suction in the upper part of the bore, said block being arranged to receive thereunder yarns which are changed.

2. In a circular knitting machine, mechanism as described in claim 1, and yarn clipping means comprising a ring rotatable with said needles, said ring having outward projecting cutter teeth on its periphery, a stationary shear block bearing on a portion of said ring over some of said teeth, and a spring pressing said block resiliently on said ring.

3. In a circular knitting machine, mechanism as described in claim 2, said shear block having at its forward end a hardened blade element bearing directly on said ring, said block having a floating attachment to said spring.

4. In a circular knitting machine, mechanism as described in claim 3, said shear block having at its rear end a wear piece of the same material as said blade element.

5. In a circular knitting machine having yarn changing mechanism and means for cutting the yarns when changing, a block located between said yarn changing mechanism and said cutting means with a clearance under part of the bottom of the block to receive yarns which are being changed, said block having a vertical bore opening out at said clearance, said bore having a short portion at its lower end of smaller diameter than the upper portion of the bore the two portions having a conical seat between them, a ball having a diameter slightly less than that of the upper portion of the bore resting on said seat and adapted to be raised by suction in the upper portion of the bore, and means for producing suction in said bore above the ball.

6. In a circular knitting machine, yarn clipping means comprising a rotatable ring having outwardly projecting teeth on its periphery, an elongated shear block with a cutting edge at one end bearing directly on said ring to cooperate with the teeth thereof, said block having a central protuberance on the top surface thereof, and carrying thereon, between said protuberance and the respective ends of the block two upstanding elements, and a leaf spring pressing on said protuberance, said spring having two holes through which said respective upstanding elements loosely extend.

'7. In a circular knitting machine, yarn clipping means as described in claim 6, said shear block having at its forward end a hardened carbide steel inset with a cutting edge bearing on said ring and at its rear end a carbide steel wear piece bearing on said ring.

References Cited by the Examiner UNITED STATES PATENTS Re. 25,584 5/1964 Stack et a1. 66l40 2,579,773 12/1951 Williams 30350 2,884,775 5/1959 Stack 66163 3,079,779 3/1963 Butler et al 6614O 3,083,553 4/1963 Moss et al 66-140 RUSSELL C. MADER, Primary Examiner.

DONALD W. PARKER, Examiner.

Claims

1. IN A CIRCULAR KNITTING MACHINE HAVING A CIRCULAR SERIES OF NEEDLES AND EQUIPPED FOR YARN CHANGING, MEANS FOR HANDLING THE YARNS WHEN CHANGES ARE MADE, SAID MEANS COMPRISING A PLATE SURROUNDED BY SAID NEEDLES, A BLOCK MOUNTED ON SAID PLATE, SAID BLOCK HAVING A VERTICAL BORE EXTENDING UPWARD FROM THE BOTTOM THEREOF SAID A CLEARANCE BETWEEN A PORTION OF THE BOTTOM AND SAID PLATE COMMUNICATING WITH SAID BORE, TUBE CONNECTIONS WITH THE UPPER PART OF SAID BORE FOR CREATING SUCTION THEREIN, THE LOWER PORTION OF SAID BORE BEING A SMALLER DIAMETER THAN THE UPPER PORTION THEREOF, A BALL IN SAID UPPPER PORTION HAVING A DIAMETER SLIGHTLY LARGER THAN THAT OF SAID LOWER PORTION OF THE BORE AND ADAPTED TO BE RAISED BY SUCTION IN THE UPPER PART OF THE BORE, SAID BLOCK BEING ARRANGED TO RECEIVE THEREUNDER YARNS WHICH ARE CHANGED.