US2995914A

US2995914A - Fabric tensioning device

Info

Publication number: US2995914A
Application number: US817871A
Authority: US
Inventors: Walter H Imboden
Original assignee: Textile Machine Works
Current assignee: Textile Machine Works
Priority date: 1959-06-03
Filing date: 1959-06-03
Publication date: 1961-08-15
Anticipated expiration: 1978-08-15

Description

Aug. 15, 1961 w. H, IMBODEN 2,995,914

FABRIC TENSIONING DEVICE- Filed June a, 1959 FlE- E. m 27 37 2a 57 2 we INVENTOR. Wa/ter H. /mboaen A TTVRNEY United States Patent sylvama Filed June 3, 1959, Ser. No. 817,871

7 Clai ms. (Cl. 66-150) The instant invention relates to improved fabric takeoifs for circular knitting machines and more particularly to such take-offs employing a stream of air to tension the fabric, such as a stocking, as it is being knit, and after the fabric is pressed off from the needles of the knitting machine, to carry it to a collection chamber from which it may be discharged into a collection tray or other receptacle.

A take-off of the above type and of which the present invention is an improvement is shown, for example, in the co-pending application of St. Pierre et al., Serial No. 500,756, filed April 12, 1955 and in the Italian Patent No. 538,758, issued January 30, 1956 corresponding thereto, referred to hereinafter as the St. Pierre et al. disclosure." In the operation of knitting machines equipped with such take-offs providing a sufficient volume of air for an adequate tensioning of the fabric it is found preferable at times and essential at other times to interrupt the air stream. For example, when the fabric is pressed off of the needles continuation of the air stream tends to ravel back the last knitted courses, as the fabric or stocking is whisked away in the air stream, before the cutter of the usual clamp and cutter is able to operate. Also during the knitting of the heel and toe and particularly the former it is often found preferable to relieve the tension on the fabric to prevent the enlargement of the loops held on the idle needles. Similarly in the knitting of the makeup courses for a womans stocking, where in order to form a turned welt the yarn is fed alternately to needles and to dial bits, the air stream exerts a disrupting infiuence.

While in constructions such as described in the St. Pierre et a1. disclosure as well as in other prior suction take-offs means have been proposed for interrupting the air stream, as for example by shutting off the suction fan or by closing a valve in the conduit leading to the suction fan, these proposals have not adequately solved the problem and also have created problems of their own in that they employ the opening of the door to the collection chamber to operate the suction cutoff or result in intermittent operation of the fan motor or both.

The principal object of the instant invention is the provision of an improved suction take-off in which the suction fan may be operated continuously and the door to the collection chamber may be maintained closed at all times except when a stocking is to be removed but in which the air stream leading from the knitting machine and through the collection chamber may be interrupted at any time desired.

Another object of the invention is the provision of a device as defined above incorporating pattern controlled means for separately effecting the opening of the collection chamber door and the interrupting of the air stream.

A still further object of the invention is the provision of such device comprising a door for said collection chamber with means for normally holding it in closed position and a pattern controlled solenoid for moving it to open position. A still further object is the provision in such mechanism of a port in the collection chamber, providing communication with a conduit leading to the suction fan, and a port in the conduit leading to the atmosphere, and solenoid operated closure members for said ports. Another object is the provision of pattern controlled means for energizing said solenoids for said door and closure members.

Briefly described the instant invention resides in a suction take-off of generally conventional type including a tube extending into the needle cylinder and having an open mouth adjacent the knitting point, said tube leading to and in communication with the collection chamber and a second tube or conduit leading from the chamber and in communication with the intake side of a suction fan. In accordance with the instant invention the chamber has a swingable door, with means, such as a counterweight, for normally maintaining it in closed position. The chamber is further provided with a port opening into the conduit leading to the suction fan the conduit having a second port leading to the atmosphere. Closures for said ports are mounted in a manner whereby upon closing the first port the second port is opened. The operating means for both the port closures and also for opening the door comprise solenoids connected into electrical circuits energized by the closing of switches by buttons on the pattern means of the machine.

By the construction described above the air stream created by the suction means, and which normally passes through the tube and into the collection chamber and thence through the port in the wall thereof to the suction fan, may be interrupted at any time desired without the necessity of opening the door of the collection chamber. Thus by locating buttons at the appropriate places on the pattern means the solenoids for the port closures may be operated to close off communication between the fan and the collection chamber and to simultaneously open the conduit to the atmosphere. When a stocking has reached the collection chamber it may be removed by similarly interrupting the air stream and during such interruption energizing the solenoid for the door to the collection chamber to open said door, this operation also being under pattern control.

My invention will be more fully understood and further objects and advantages thereof will become apparent when reference is made to the more detailed description thereof which is to follow and to the accompanying drawings in which:

FIGURE 1 is a diagrammatic elevational view with parts in section illustrating a device embodying the instant invention; and

FIG. 2 is a sectional view taken on the line 22 of FIG. 1.

Referring now to the drawings and particularly to FIG. 1, there is diagrammatically shown the knitting head of a conventional circular independent needle knitting machine, such as a womans hosiery machine, including a cylinder 1, needles 2 slidable in the usual needle slots, sinkers 3 in a sinker-head 4 and a dial 5 carrying the usual dial bits (not shown). Extending interiorly of the needle cylinder 1 is a fabric receiving tube 6 including a preferably funnel shaped mouth piece 7 terminating adjacent the point of formation of the fabric produced on the machine. Tube 6, preferably made of a clear plastic or the like, extends downwardly suitably for a distance at least equal to the length of the fabric to be formed on the machine and leads through a series of reverse bends 8 to a collection chamber 10 and is secured in relatively airtight relationship to an upper wall 9 around an opening therein providing communication between the interior of the chamber and the tube. The apparatus so far described may be generally the same as that shown in said St. Pierre et al. disclosure and may include the specific features thereof.

In accordance with the instant invention the collection chamber 10 (FIGS. 1 and 2), suitably of cylindrical cross section, includes, in addition to the upper wall 9, an annular side wall and an opening or doorway 11 in its as the annular wall of chamber 10. A second arm 23 of lever 14 has its free end pivotally secured as by a pin 16 to one end of a link 17 the other end of which is pivotally connected as at 18 to an extension 19 of the core member of a pull type solenoid 20. Suspended from the pin 16 is a link 21 supporting a counterweight 22 of sufl'lcient mass in relationship to the

lever arms

13 and 23 to normally maintain door 12 in a position to close doorway 1-1.

The annular wall of chamber is provided with a port 25 having therein a wire mesh screen or the like 26 of suificient porosity to permit the free flow of air through the port while at the same time preventing a stocking or other fabric from being drawn through the port, by the suction means hereinafter to be referred to. The chamber and associated elements described above may suitably be made of metal although the'particular materials of which they, as well as other parts, are constructed is not critical as will be understood.

Exteriorly of the chamber, port 25 is surrounded by a collar 27 defining a seat for a port closure 28 the latter suitably consisting of a lightweight fiat sheet of sufiicient area to overlie the opening defined by collar 27. Closure 28 is rigidly secured to a member 29 mounted for free rotation on a pin or shaft 30 which in turn is mounted in any suitable means such as the walls of a casing 37. Member 29 includes a lever arm 31, the latter having its outer end pivotally connected to a rod 32. Rod 32 is in turn pivotally connected to the extending end 33 of the core member of a pull type solenoid 34.

Casing 37, which is airtight or substantially airtight except for the openings hereinafter referred to, surrounds collar 27 and its lateral and top and bottom walls are suitably seamed, as by welding, to the annular wall of chamber 10. The casing is of sufiicient size to permit the swinging of closure 28 between a position in which it is in contact with the collar 27 to close port 25, the dotted line position of the closure, and an open position, the full line position of the closure (FIG. 1). Casing 37 also includes an upward extension enclosing the elements 30 and 31 and a portion of rod 32. The upward extension is provided with a port 38 through which rod 32 projects. A closure member 39 for port 38 is carried by rod 32 the closure member including a disk 40 having a collar 41 secured as by a set screw 42 to the shaft 32. A disk or ring 43 of rubber or other suitable gasketing material is secured to disk 40 to provide a substantially airtight seal with the chamber walls when closure 39 is in port closing position. As will be observed closure 39 is so adjusted on shaft 32 that when member 29 is rotated to move closure 28 to its open position, closure 39 is moved to its port closing position and vice versa.

A tube 44 is connected into an opening in the lower wall of casing 37 and leads to and is in communication with the intake side of a suction fan 45 adapted for continuous operation as by motor 46. For purposes of convenience in description and claiming the tube 44 and casing 37 will hereinafter sometimes be referred to together as a conduit.

Solenoids 20 and 34 are connected into an electrical circuit to be energized in timed relationship to the operation of the knitting machine. For this purpose the solenoids are connected by

leads

47 and 48 respectively to a main line or power source 49 through normally open microswitches 50 and 51 respectively. Microswitches 50 and 51 are supported in a suitable manner, not shown, adjacent a conventional pattern drum or other pattern means 52 of the knitting machine the pattern means carrying a plurality of annular rows of buttons for initiating various movements of the machine. Annular rows of

buttons

55 and 56 are assigned to the microswitches 50 and 51, respectively. Each of the switches 50 and 51 includes a spring biased contact member, 53 and 54 respectively, adapted when depressed against the action of its spring to close its switch. Each of the contact members has a roller positioned to ride up on the

buttons

55 or 56 making up the row opposite it. Drum 52 is rotated at intervals by any conventional means, not shown, to move the buttons into and out of contact with the contact members to close the switches for predetermined intervals measured by the circumferential extent of the buttons and to then permit the switches to open.

In the operation of the knitting machine described above motor 46 is continuously operated to drive the suction fan 45. Assuming that at the start of the operation the pattern drum 52 is positioned so that the switches 50 and 51 are open and the solenoids de-energized, the suction force will cause port closures 28 and 39 to move to open and closed positions, respectively. Also door 11 will be maintained in closed position by counterweight 22. As a consequence an air stream is drawn through the funnel mouth 7 of the tube 6, through the tube and collection chamber and to the fan. During this operation the fabric being formed by the knitting instrumentalities of the knitting machine enters mouth 7 and extending into tube 6 is entrained and tensioned by the air stream. When the knitting is completed and the last course of fabric is "pressed off the needles the air stream then serves to deliver the completed stocking to the collection chamber 10. As previously pointed out it has been found desirable, if not essential, at certain times to interrupt the air stream to relieve the tension on the fabric particularly in the knitting of womens hosiery.

Thus if the air stream continues during the knitting of the make-up courses, namely those courses formed by the needles and transfer bits, the movement of air around the needles and bits provides a disrupting influence. Again during the reciprocating knitting of the heel pocket the constant tensioning of the fabric by the air stream creates an undesirable pull on the loops held by the idled needles tending to elongate them. Also after completion of the stocking and the pressing off of the fabric loops from the needles, if the air stream is in operation it immediately Whisks the stocking through the tube and toward the collection chamber this occurring before the thread cutter has an opportunity to sever the yarn with the result that a number of courses of the loopers round may be raveled back. The instant invention eliminates these problems in that it permits the interruption of the air stream and its tensioning effect on the stockings during these periods or any other period in which such interruptions are found desirable. Thus by proper arrangement of the buttons on the pattern means solenoid 34 may be energized at any appropriate point in the knitting cycle to move rod 32 to the right as shown in FIG. 1 to move closure 39 away from the port 38 and to swing closure 28 against collar 27 whereby the air stream through the tube 6 and chamber 10 is interrupted and air is drawn through port 38. As soon as the solenoid is deenergized the air drawn by the fan serves to swing closure 28 to open position and to simultaneously move closure 39 to closed position whereby the air is again drawn through the complete system. During all such interruption of the air stream door 12 is held in closed position by the counterweight except the one occasion in each knitting cycle when the fabric is deposited in the collection chamber and is to be delivered therefrom to a tray 57. On this occasion the air stream is briefly interrupted as described above and substantially simultaneously therewith the solenoid 20 is energized by a properly placed button on the pattern means to open door 11 and allow the stocking to drop out of the chamber into the tray 57.

Having thus described my invention in full detail it will be understood that various changes and modifications may be made therein without departing from the scope of the accompanying claims.

I claim:

1. ln a suction take-off for a circular knitting machine, a tube adapted to receive fabric formed on the machine leading to and in communication with a collection chamher, a door in said chamber, and a conduit leading from said chamber to a suction means whereby a flow of air is created through said tube and collection chamber, the improvement comprising means for interrupting said flow of air through said tube and chamber, and means for simultaneously opening said conduit to the atmosphere while maintaining said door in closed position.

2. In a suction take-oft device for a circular knitting machine, a tube adapted to receive fabric formed onthe machine leading to and in communication with a collection chamber, a door in said chamber, and a conduit leading from said chamber to a suction means whereby a flow of air is created through said tube and chamber, the improvement comprising a port in said chamber providing communication between said chamber and said conduit, a second port in said conduit providing communication between said conduit and the atmosphere, and means for simultaneously closing said first port and opening said second port while maintaining said door in closed position.

3. In a suction take-off for a circular knitting machine,

a tube adapted to receive fabric formed on the machine leading to and in communication with a collection chamber, a door in said chamber and a conduit leading from said chamber to a suction means whereby a fiow of air is created through said tube and chamber, the improvement comprising a port in said chamber providing communication between said chamber and said conduit, a second port providing communication between said conduit and the atmosphere, and pattern controlled means for automatically closing said first port and opening said second port at predetermined times in the operation of the knitting machine while maintaining said door in closed position at certain of said times. 4. A device as claimed in claim 3 in which said means for simultaneously closing said first port and opening said second port comprise solenoid operated closures for said ports and said controlling means comprises an electrical circuit and a pattern operated switch for opening and closing said circuit.

5. In a suction take-off for a circular knitting machine, a tube adapted to receive fabric formed on the machine leading to and in communication with a collection chamber, a door in said chamber, and a conduit leading from said chamber to a suction means whereby a flow of air is created through said tube and chamber, the improvement comprising means for normally maintaining said door in a closed position, means for opening said door, a port in said chamber providing communication between said chamber and said conduit, a port in said conduit providing communication between the conduit and the atmosphere, and pattern controlled means for at times closing said first port and opening said second port while said door is maintained in closed position and at another time substantially simultaneously with the operation of said door opening means.

6. In a suction take-off for a circular knitting machine, a tube adapted to receive fabric formed on the machine leading to and in communication with a collection chamber, a door for said chamber and a conduit leading from said chamber to a suction means whereby a flow of air is created through said tube and chamber, the improvement comprising means for normally maintaining said door in closed position, means for opening said door, a port in said chamber providing communication between said chamber and said conduit, a closure for said port normally maintained in open position, a port in said conduit providing communication between the port and the atmosphere, a closure for said second port normally maintained in closed position, means for operating said port closures, and pattern controlled means for energizing said port closure operating means to close said first port and simultaneously open said second port and at times to energize said door opening means to open said door substantially simultaneously with said operation of said closure operating means.

7. A device as claimed in claim 6 in which said door opening and closure operating means comprise solenoids and controlling means therefor comprising electrical circuits including switches operated by a pattern device.

References Cited in the file of this patent UNITED STATES PATENTS 961,364 Maclaren June 14, 1910 FOREIGN PATENTS 202,394 Australia July 5, 1956 801,449 Great Britain Sept. 17, 1958 1,183,041 France Jan. 26, 1959