US3461692A

US3461692A - Yarn feed device for a knitting machine

Info

Publication number: US3461692A
Application number: US708027A
Authority: US
Inventors: Jean-Pierre Raisin
Original assignee: Institut Textile de France
Current assignee: Institut Textile de France
Priority date: 1967-02-27
Filing date: 1968-02-26
Publication date: 1969-08-19
Anticipated expiration: 1986-08-19
Also published as: BE710618A; DE1635818B2; DE1635818A1; FR1522316A; GB1160494A; DE1635818C3; ES351235A1

Description

Aug. 19, 1969 JEAN-PIERRE RAISIN 3,451,692

YARN FEED DEYICE FOR A KNITTING MACHINE 5 Sheets-Sheet 1 Filed Feb. 26, 1968 mvmran a JEM- PIERRE RflIj/N mi flaw Aug. 11969 7 JEANEPIERRE RAISIN 3,461,692

YARN FEED DEVICE FOR A KNITTING MACHINE Filed Feb. 26, 1968 5 Sheets-Sheet 2 JEMI- PIERRE RFII SIN WW M wnw

Aug. 19, 1969 JEAN-PIERRE RAISIN 3,461,692

YARN FEED DEVICE FOR A KNITTING MACHINE Filed Feb. 26, 1968 i s Sheets-Sheet :5

INvENTaK JEMI- PIERRE Mlsnv Aug. 19, JEAF-PIERRE RAISIN YARN FEED DEVICE FOR A KNITTING MACHINE Filed Feb. 26. 1968 5 sheets sheet L A 1959 JEANPIERRE RAISIN 3,461,692 YARN FEED DEV ICE FQR A KNITTING MACHINE Filed Feb. 26, 1968 r 5 Sheets-Sheet 5 5a I V 59 V 6 69 [it m Z5 N e I 9 7 55 2&2; [El

Fig. 6v

INVENTOR JEAN-PIERRE Rmsm United States Patent 3,461,692 YARN FEED DEVICE FOR A KNITTING MACHINE Jean-Pierre Raisin, Troyes, France, assignor to Institut Textile de France, Boulogne-snr-Seine, France Filed Feb. 26, 1968, Ser. No. 708,027 Claims priority, application France, Feb. 27, 1967,

96,585 Int. Cl. D04b /48 US. Cl. 66-432 2 Claims ABSTRACT OF THE DISCLOSURE A yarn feed device for a knitting machine including a yarn guide operatively associated with the yarn carrier bar, means being provided to control the position of the yarn guide in dependence upon the position of the yarn carrier bar so that the length of yarn between the yarn guide and yarn carrier is always constant. Means are also provided to control the starting and stopping of the yarn feeder in dependence upon the position of the yarn carrier bar.

The present invention relates to a yarn feeding device for a. cotton type machine.

Knitting on a cotton type machine is generally concerned with producing well-proportioned knitted panels, i.e., panels which, when taken from the machine, have a shape which is as near as possible to that which they will have in the finished article.

It is therefore important that for a batch of similar articles having identical dimensions all the panels made have identical dimensions, whatever may be the thread used, the colour of the yarn, manner of preparation and no matter what kind of machines are used, or what type of knitting head is used in a particular machine.

Experience has shown that all these parameters influence the dimensions of the knitting. Adjustment of the machine itself also plays a part and the speed of formation of the stitches and the feed tension of the yarn are quite important factors. It is thus very difficult, particularly when the yarn is changed (change of batch, of colour, of origin to match panels with regard to the tightness of the knitting and their dimensions.

The cotton type machine used hooked needles which are mounted on a needle bar. The loop sinkers serve to loop the yarn deposited by the yarn carrier, at every other needle at the commencement of the formation of the stitches.

The loop dividers are intended to divide the yarn taken by the loop sinkers so as to distribute it between all the needles. The loop sinkers and loop dividers are alternately disposed in a sinker head so as to be movable and perpendicular to the needle bar, the sinker head having a loop sinker at each end. Levers, known as jacks, act respectively on the corresponding loop sinkers. They are disposed in a jack head and actuated by means of a slur cam box bar. The yarn carrier is disposed on a yarn carrier bar.

It is well known that it is the loop sinkers and loop dividers which loop the yarn around the needles. This operation is generally carried out in two motions.

Whereas a yarn carrier deposits the yarn in front of the needles, the loop sinkers advance successively one after the other and thus cause looping of sufiicient yarn for the formation of the stitches.

The loop sinkers thereafter move back slightly to enable the loop dividers to move forward to deposit around each needle the quantity of yarn necessary for each loop.

The considerable importance played by the chafing 3,461,692 Patented Aug. 19, 1969 phenomenon, which accompanies the formation of a stitch on a cotton type machine, will be readily understood. The quantity of yarn fed to a needle depends on this because a section of yarn producing considerable chafing remains taut between two neighbouring needles and the sinkers and dividers, so that very small loops are obtained, after formation of the stitch, whereas a yarn which slides easily remains slack and produces larger loops.

The origin of the dimensional variations referred to above can be explained by this phenomenon.

The present invention eliminates the above-mentioned disadvantages and has for a main object to provide a yarn feed device for a cotton type machine which enables an accurate quantity of yarn at constant tension to be fed to each needle.

According to the invention a yarn feeding device for a cotton type rectilinear machine having hooked needles mounted on a needle bar, loop sinkers and loop dividers alternately movably disposed and perpendicular to the needle bar in a sinker head, levers disposed in a jack head acting on the loop sinkers and actuated by means of a slur cam box bar, and a yarn carrier secured to a yarn carrier bar movably mounted in a direction parallel to the axis of the needle bar, comprises a yarn feeder having a fixed axis of rotation, a yarn guide mounted in a medial plane and perpendicular to the needle bar and movable in this plane in a vertical direction, a yarn return movably mounted on the yarn guide about an axis of rotation perpendicular to the plane of movement of the yarn guide, mechanical connecting means between the yarn carrier bar and the yarn guide, means controlling the position of the yarn guide as a function of the positions of the yarn carrier and yarn carrier bar so that the length of yarn between the output of the yarn guide and the yarn carrier remains constant whatever the position of the yarn carrier with respect to the needle bar, and means controlling the starting and stopping of the yarn feeder according to the position of the yarn carrier bar and the slur cam box bar.

By means of the invention constant. yarn feed at predetermined yarn tension can be obtained.

In order that the invention may be more fully understood, two embodiments in accordance therewith will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a partial perspective view of a cotton machine;

FIG. 2 is a schematic side view of a cotton machine showing its general layout;

FIG. 3 is a diagrammatic view showing in detail a first embodiment of the feed device of the invention;

FIG. 4 shows a second embodiment of the feed device of the invention; and

FIGS. 5-7 are diagrammatic views of means for controlling the starting and stopping of the feeder.

FIGS. 1 and 2 show the principle basic elements of a cotton machine The hooked needles 1 are mounted. at their bases on a needle bar 2 which is mounted to be movable in a vertical plane and in a horizontal plane in a needle bar support 3. Perpendicular to the needle bar 2 is provided a sinker head 4 in which are movably and alternately disposed the loop sinkers 5 and the loop dividers 6, a loop sinker 5 being disposed at each end of the machine.

As can be seen more particularly from FIG. 1, the loop sinkers 5 serve to loop the yarn 7 coming from a yarn carrier 8, at every other needle 1 at the commencement of the formation of the stitches, this operation being known as loop sinking.

The loop sinkers 5 are actuated by levers known as jacks 9, the number of loop sinkers 5 for every knitting head of the machine being equal to half the number of needles 1 plus one.

The loop dividers 6 are intended to divide the yarns 7 taken by the loop sinkers in such a way as to divide them equally between all the needles 1. The loop dividers are rearwardly extended by shanks 10 intended to reinforce the sinker butt and to guide the jacks 9, so that the latter are always accurately aligned with the loop sinkers 5.

The loop sinkers 5 and the loop dividers 6 are alternately and movably disposed in the sinker head 4, a loop sinker being located at each end of the sinker head 4. The lower portion 4a of the sinker head constitutes the press. Each of the jacks 9 acts upon a corresponding loop sinker 5. The jacks are contained in a jack head (not shown) and are actuated by means of a slur cam box bar 11.

The knitting surfaces 12 of the sinkers have a tooth to hold the stitches of the knitting 13 and a projection which receives the loops coming off the loop sinkers and

dividers

5 and 6 at the moment of knock-over.

The knitting surfaces of the sinkers 12 are disposed in recesses in a brass bar or knock-over comb 14. The yarn carrier or carriers 8 are mounted on bars 15 which slide in supports fixed to the central bed of the machine. The number of yarn carriers 8 carried by such a bar, which is known as a yarn carrier bar 15, is equal to the number of knitting heads of the machine. A spring bar 16 cooperates with the rear ends of the jacks 9 and is constituted by a bar in which springs are mounted. Its effect is to prevent the loop sinkers 5 from rebounding when they hit the cover member 19 mounted on the upper portion of the sinker head 4. A movable bar 17 cooperates with brackets of the loop sinkers 5 and the butts of the loop dividers 6.

The formation of a stitch is performed in the following manner: the needles 1 are in their high position and the lop sinkers 5 and loop dividers 6 are withdrawn with the sinker head 4; the knitting surfaces 12 of the sinkers are in their low position.

The movable bar 17 rises and in doing so frees the brackets 18 of the loop sinkers 5. The yarn carrier 8 deposits the yarn 7 on the projections of the loop sinkers 5, which start to advance successively as soon as the yarn carrier 8 has advanced laterally sutficiently with respect thereto. The loop sinkers 5 loop the yarn 7 at every other needle 1 under the action of the slur cam box bar 11 on the jacks.

While the last loop sinkers 5 are finishing their advancing movement, all the loop dividers 6 are pushed at the same time by the movable bar 17 against the cover member 19 to align them with the loop sinkers 5.

During this movement, when the divider throats 20 of the loop dividers 6 reach the yarn 7 held taut between two needles, the loop sinkers"5 will be caused to move backwards sufficiently to enable the yarn 7 to follow the advance of the loop dividers 6. The loops are thus equalised at the moment when the extremities of all the loop sinkers and

dividers

5 and 6 are removed at the end of their travel. The movable bar 17 is lowered on the brackets 18 of the loop sinkers 5.

This part of the operation of the cotton type machine has been described in order that the object of the present invention, which is more particularly shown in FIGS. 3 and 4, can be better understood.

A cylindrical yarn feeder 21 rotatable about a horizontal axis is provided in the machine at a predetermined location arxd receives the yarn 7 from a reel (not shown), such yarn 7, which passes around the feeder 21, being guided by means of three fixed guiding

eyelets

22, 23 and 24. The driving mechanism and the means for controlling the starting and stopping of the yarn feeder 21 depending upon the position of the yarn carrier bar 15 and the slur cam box bar 11 are shown in FIGS. 5 to 7 and will be described later. The yarn 7 then passes over a yarn guide 25 having the form of a right-angled bracket. This bracket 25 is disposed in the medial plane perpendicular to the needle bar 2.

The bracket comprises a vertical portion 26 which is vertically movable and guided in fixed

bearings

27 and 28. A return spring 29 acting on the lower bearing 28 constantly maintains the lower end of the portion 26 in contact with a control cam 30 through the agency of a contact roller 31. This cam 30, known as the distance compensation cam, is connected to the yarn carrier bar 15 which carries the yarn carrier 8, by means of a chain transmission 32 and a rack and pinion transmission 33. The rod of the rack is rigid with the yarn carrier bar 15. The yarn 7 passes through an opening formed in the portion 26 before passing through two other openings provided in the extreme angular portion 34a of the arm 34 of the bracket 25.

The yarn return 35 is fixed to the rear end of the arm 34. This yarn return is constituted by a sprung lever, one end of which is mounted on the rear portion of the arm 34 and the other end of which carries an eyelet 36 through which passes the yarn 7. The

yarn return

35, 36 enables the yarn 7 to be held taut when the yarn carrier 8 stops and thus enables the quantity of yarn fed by the yarn feeder 21 to be absorbed.

It Will be easily understood that if the forward end 34a of the arm 34 of the bracket 25 were fixed, the length of yarn between the yarn carrier 8 and the point 34a would vary as a function of the position of the yarn carrier 8 with respect to its central position PC. If x designates the distance between the two extreme positions PE or PE and the central position PC, and h is the length of yarn between the yarn carrier 8 and the arm 34a when the yarn carrier is in its central position, it will be seen that the length of yarn between the yarn carrier 8 and the forward end 34a of the arm 34 varies by an amount equal to i( /h +x h) according to which of the extreme positions of the yarn carrier 8 is considered, if the point 34a is fixed. In other words, the length of this part of the yarn and thus the tension thereof vary, and the various loop sinkers 5 do not act upon constant amounts of yarn.

By means of the invention, the yarn guide is :made movable in a plane vertical to the needle bar 2 and its movement is controlled as a function of the yarn carrier 8.

The distance compensation cam 30 has a profile which takes into account the value A and is equal to In this Way, the length of yarn between the yarn carrier and the forward end of the yarn guide bracket 25 remains constant, so that the tension of the yarn also remains constant whatever may be the position of the yarn carrier 8. At the end of the travel of the yarn carrier 8, the latter stops at the level of the last loop sinker 5.

During a first stopping period of the yarn carrier 8, the last loop sinkers 5 still form loops. The yarn carrier 8 still occupies its rest position during the operations of shaping, pressing, assembling, knocking over, rehooking and lifting.

The yarn feeder 21 continues, however, to pass yarn during the first stopping period of the yarn carrier 8 and it is thereafter stopped by control means which will be described later with reference to FIGS. 5 to 7. It is then the yarn return 35 which rises whilst rocking rearwardly and which thus absorbs the amount of yarn fed by the feeder 21 during the first stopping period of the yarn carrier 8 until the moment when the feeder 21 stops.

After the execution of all the above-mentioned operations of the machine, the yarn carrier 8 starts a new travel towards the other end of the needle bar 2 and first uses the yarn stored on the yarn return 35 which is lowered towards the end 34a of the yarn guide 35. It is at this point that the first loop sinker 5 emerges from the sinker head 4 and that, at the commencement of this action, the yarn feeder 21 restarts.

Since the yarn carrier 8 moves with the yarn carrier bar with which the rack 33 is rigid, the transmission 33 starts up together with the chain transmission 32, which controls the distance compensation cam 30 of the yarn guide 25. The yarn 7 is once more supplied to the needles 1 in constant amount and at constant tension.

In FIG. 4, there is shown a second embodiment of the invention practically identical with that shown in FIG. 3. In the present case, the only difference resides in the fact that the roller 31 of the portion 26 of the yarn guide cooperates with a cam profile 38 mounted on the yarn carrier bar 15. This profile 38 also follows the equation A=i( /h +x -h).

Driving of the yarn feeder 21 is effected by the drive mechanism shown in FIG. 5. This drive mechanism is connected by means of two

gears

40, 41 to the cam shaft 42 of the machine. One of these gears is keyed to the cam shaft 42, while the other is mounted on the input shaft 43 of a variable speed device 44. The cam shaft 42 always turns in the same direction.

The output shaft 45 of the variable speed device 44 is connected to an electromagnetic clutch 46 of which the output shaft 47 cooperates with an electromagnetic brake 48. The output shaft 49 of the brake 48 is connected to the shaft 50 of the feeder 21 by means of two pairs of

pinions

51, 52 and 53, 54.

The variable speed device 44 enables the speed of rotation of the feeder 21 to be modified with a view to prior adjustment of the size of the knitting stitches. The clutch 46 and the brake 48 ensure the operation and stopping of the feeder 21.

Since the width of a knitted panel must frequently be decreased (putting certain needles out of action) or increased (putting into action of additional needles), the moment of clutching and braking of the yarn feeder 21 cannot be adjusted once and for all. There is therefore provided means for controlling the starting and stopping of the feeler 21 as a function of the position of the yarn carrier bar 15 and the slur cam box bar 11.

For this purpose, each end of the yarn carrier bar 15 cooperates with an end of travel abutment 55, the position of which is adjustable, and carries a finger 56 closing a switch 57 fixed to the abutment 55 (FIG. 6) and mounted in series with a control relay '58, one of the

contacts

59, 60 of which is mounted in series with the excitation winding 61 of the brake 48, and the other contact 60 of which is mounted in series with the excitation winding 62 of the clutch 46.

The slur cam box bar 11, which in moving drives the yarn carrier bar 15 through friction means until the yarn carrier bar is stopped by the abutment 55, cooper-' ates at each of its ends successively with a switch 63 or 64 (FIG. 6) mounted in series with a relay 65 controlling a contact 66 which, depending on whether the relay 65 is excited or not, is connected in series with the winding '62 of the clutch 46 or the contact 59 and the winding 61 of the brake 48 and then cooperates with one of the end of travel switches 67, 68 mounted one behind the other and in series with the winding 62 of the clutch 46. The

switches

67, 68 are generally closed and only open when they are actuated by one of the slur cam box bar 11.

The other end of the carrier bar 15 cooperates with an abutment (not shown) and with an end of travel switch 69 connected in parallel with the switch 57. The

switches

63, 64 are connected in parallel and are only closed when actuated by the slur cam box bar 11. The

switches

57, 69 are closed when actuated by the corresponding finger of the yarn carrier bar 15. The series circuits constituted by the

switches

57 or 69 and the relay 58, by the

contacts

66, 59 and the winding 61, by the

contact

60 or 66, the

switches

67, 68 and the winding 62 and by the

switch

63 or 64 and the relay 65 are connected in parallel between the lines 70, 7-1 leading for example from the secondary winding of a transformer.

The yarn carrier bar 15 is driven by the slur cam box bar 11 by means of friction elements (not shown). At each end of travel, the yarn carrier bar 15 is stopped by an abutment, for example by the abutment 55 when the bar '15 moves from left to right, while the slur cam box bar 11 continues its movement for at least several centimeters further.

During operation of the feeder 21, the various contacts and switches occupy the positions shown in FIG. 7. Since the

relays

58 and 65 are not supplied, the contact 60 is closed and the contacts 66 occupies its high position, the clutch winding 62 being excited through the

contacts

60 and 66 and the

closed switches

67, 68. Thus the feeder 21 is coupled to the variable speed device 44 and delivers the yarn necessary for knitting. When the yarn carrier bar 15 is stopped in its left to right movement by the abutment 55, the switch 57 closes to cause the relay 58 to be supplied, and this, by placing the contact 59 in its closed position, prepares the supply to the winding 61 of the brake 48, the opening of the contact 60 remaining for the moment without influence on the feed of the winding 62 of the clutch 46 since the contact 66 is closed in the high position.

The yarn carrier bar 15 is thus stopped, but the feeder 21 still delivers the amount of yarn necessary at the end of the looping, the relay 65 not yet being supplied.

The slur cam box bar 11 leaves the yarn carrier bar 15 and, in continuing its movement, it first closes the switch 63 and then a few moments later opens the switch 67. Closure of the switch 63 causes the relay 65 to be supplied and this places the contact 66 in its low position where it simultaneously cuts off the supply to the winding 62 of the clutch 46 and closes the supply circuit (contact 59 already closed) of the Winding 61 of the brake 48. The yarn feeder 21 is thus stopped. At the end of its travel, the slur cam box bar 11 opens the switch 67, which is in the supply circuit of the winding 62 of the clutch 46, but this is for the moment without importance. The movement from right to left of the slur cam box bar 11 and the yarn carrier bar 15 can then commence and proceeds as follows:

The slur cam box bar 11 on starting to move, moves with it the yarn carrier bar 15, so that the switch 57 opens and cuts off the supply to the relay 58. As a result, the contact 59 opens and interrupts the supply circuit of the winding 61 of the brake 48 and the contact 60 simultaneously closes, thus preparing the supply to the winding 62 of the clutch 46; but the switch 67 still remains open because the slur cam box bar 11 is still acting on the switch 67.

Continuing its movement from right to left, the slur cam box bar 11 liberates the switch 67 which closes to ensure again that the winding 62 of the clutch 46 is supplied with voltage.

From this moment, the yarn feeder 21 again delivers yarn, but with the necessary delay with respect to the start of the movement of the yarn carrier bar 15 and thus of the yarn carrier 8. The importance of this delay is governed by the positioning of the switch 67 with respect to the abutment 55 and corresponding switch 57. Then the switch 63 is also freed by the slur cam box bar 11. Opening of this contact 57, and the resulting deexcitation of the relay 65 places the contact 66 in its high position, but plays no role during this movement since the supply to the winding 61 of the brake 48 was already previously cut off by the contact 59 and the supply to the winding 62 of the clutch 46 is already ensured. by the contact 60 and

closed switches

67, 68.

The driving mechanism for the feeder 21 is now once again in knitting conditions similar to those at the commencement. At the end of travel at the left hand side the control cycle of the feeder 21 is ractically identical to that described above, except that the yarn carrier bar 15 and the slur cam box bar 11 are now actuating respectively the

switches

69, 64 and 68.

The embodiments described above were in combination with a cotton machine. They could, however, be combined with other rectilinear hosiery making machines, particularly knitting machines. Such a modification remains within the scope of the present invention.

Naturally, the device of the present invention can be modified in numerous ways without departing from the scope of the invention.

What is claimed is:

1. A yarn feeding device for a rectilinear knitting machine having hooked needles mounted on a needle bar, loop sinkers and loop dividers alternately movably disposed and perpendicular to the needle bar in a sinker head, levers disposed in a jack head acting on the loop sinkers and actuated by means of a slur cam box bar, and a yarn carrier secured to a yarn carrier bar movably mounted in a direction parallel to the axis of the needle bar, said device comprising a yarn feeder having a fixed axis of rotation, a yarn guide mounted in a medial plane and perpendicular to the needle bar and movable in this plane in a vertical direction, a yarn return movably mounted on the yarn guide about an axis of rotation perpendicular to the plane of movement of the yarn guide, mechanical connecting means between the yarn carrier bar and the yarn guide, means controlling the position of the yarn guide as a function of the positions of the yarn carrier and yarn carrier bar so that the length of yarn between the output of the yarn guide and the yarn carrier remains constant whatever the position of the yarn carrier with respect to the needle bar, and means controlling the starting and stopping of the yarn feeder according to the position of the yarn carrier bar and the slur cam box bar.

2. A device according to claim 1, wherein the yarn of feeder start and stop control means comprises a cam shaft of the machine controlling the movements of the yarn carrier and slur cam bax bars, a variable speed device connected to the cam shaft, an output shaft of said variable speed device, an electromagnetic clutch and brake cooperating together, one of which is connected to said output shaft, and the other of which is operatively associated with the yarn feeder, feed circuits for the electromagnetic clutch and brake, a plurality of switches connected in the feed circuits and adapted to be actuated respectively by the ends of the yarn carrier bar and slur cam box bar, and two adjustable end of travel abutments each adapted to cooperate with one end of the yarn carrier bar and said plurality of switches.

References Cited UNITED STATES PATENTS 2,030,477 2/1936 Snader 66-432 XR 2,199,263 4/1940 Lawson 66132 2,586,205 2/1952 Cobert 66126 2,680,364 6/1954 Wickardt et al. 66146 2,777,309 1/1957 Newton 66-146 2,912,840 11/1959 Cobert 66130 XR 3,396,558 8/1968 Taylor et a1. 66132 RONALD FELDBAUM, Primary Examiner