US3625027A - Thread guide unit for circular knitting machines - Google Patents

Abstract

THIS DISCLOSURE RELATES TO A THREAD GUIDE UNIT FOR RAPIDLY REPLACING ONE THREAD WITH ANOTHER BEFORE COMMENCING THE ROWS OF KNITTING, SAID UNIT COMPRISING A DRUM OSCILLATING ABOUT ITS OWN AXIS AND PROVIDED WITH PERIPHERAL GROOVES EXTENDING PARALLEL TO SAID AXIS, SAID GROOVES BEING ARRANGED TO HOUSE THREAD GUIDE MEMBERS, A STEP CAM FAST WITH SAID DRUM, A FIRST SLIDE MEMBER FOR CAUSING THE LOWERING OF ONE OF SAID THREAD GUIDE MEMBERS, A SEC-

OND SLIDE MEMBER ARRANGED TO ENGAGE SAID STEP CAM AND LOCK SAID DRUM, A SERIES OF CONTROL MEMBERS EQUAL IN NUMVER TO THE NUMBER OF STEPS OF SAID STEP CAM, EACH OF SAID CONTROL MEMBERS BEING ARRANGED TO ENGAGE A CORRESPONDING STEP OF SAID CAM AND CAUSE THE ROTATION OF SAID DRUM.

Description

Dec. 7, 1971 F. PIANA ETAI- 3,625,027

THREAD GUIDE UNIT FOR CIRCULAR KNITTING MACHINES Filed April 14, 1969 5 Sheets-Sheet 1 INVENTORS FRANCESCO PIANA BY ANGELO BREGA Dec. 7, 1971 F. PIA NA ETAL 3,625,027

THREAD GUIDE UNIT FOR CIRCULAR KNITTING MACHINES Filed April 14, 1969 5 Sheets-Sheet 2 lNVENTOR-S FRANCESCO PIANA ANGELO BREGA PIANA ETAL 3,625,027

THREAD GUIDE UNIT FOR CIRCULAR KNITTING MACHINES Dec. 7, 1971 5 Sheets-Sheet 5 Filed April 14, 1969 Dec. 7, 1971 PlANA ETAL 3,625,027

THREAD GUIDE UNIT FOR CIRCULAR KNITTING MACHINES Filed April 14, 1969 5 Sheets-Sheet 4 INVENTORS FRANCESCO PIANA ANGELO BREGA AGENT THREAD GUIDE UNIT FOR CIRCULAR KNIT'QIIYG MACHINES Filed April 14, 1959 v F. PIANA E'rAL '5 Sheets-Sheet 5 United States Patent O 9,2 Int. Cl. D04]: 9/06, 15/58 US. Cl. 66-19 6 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a thread guide unit for rapidly replacing one thread with another before commencing the rows of knitting, said unit comprising a drum oscillating about its own axis and provided with peripheral grooves extending parallel to said axis, said grooves being arranged to house thread guide members, a step cam fast with said drum, a first slide member for causing the lowering of one of said thread guide members, a second slide member arranged to engage said step cam and lock said dr-um, a series of control members equal in number to the number of steps of said step cam, each of said control members being arranged to engage a corresponding step of said cam and cause the rotation of said drum.

BACKGROUND OF THE INVENTION The present invention relates to a thread guide unit for a circular kniting machine.

In circular knitting machines, comprising a fixed framework and a rotating equipment, and fed with a plurality of threads by an equal number of bobbins or reels, it is necessary to be able to replace one thread with another promptly and with precision, before starting the formation of rows of stitches of the knitted fabric. It is known, in fact, that in circular knitting machines, at each rotation of the rotating equipment with respect to the fixed framework, there occurs the formation of many new rows of knitting with threads coming from the feed unit and supplied by respective thread guides (which are equal in number to the feed units). After the completion of a certain number of rows with a given type of thread (for example with a given color) it is necessary, without interrupting the work rhythm of the machine, to replace the thread used until that moment with a new thread, for example of different color, in order to effect one or more successive rows of the knitting. Since the operative speed of circular knitting machines can reach high values and since it is necessary to successively feed the knitting with numerous different threads, it is clear that it is necessary to provide a thread guide distributor unit of rational conception which is such as to guarantee a sure working in all conditions of use.

SUMMARY OF THE INVENTION The thread guide unit according to the invention is designed to guarantee a precise feeding of the threads to the zone of the machine in which the formation of the knitwear takes place and to guarantee that the passage of the feeding of one thread to that of the feeding of another thread, at the moment in which a suitable control is given by the programmer unit, occurs rapidly and without uncertainties in the selection of the thread among the many available or in its positioning in the work zone.

Another object of the present invention is that of providing a thread guide unit for circular knitting machines which is of simple and sturdy structure and comprises a limited number of moving parts, so that the inertias in play during the rapid operations which lead to the re- 3,625,027 Patented Dec. 7, 1971 placement of the thread feeding the machine are as small as possible.

These and other objects which will better appear hereinafter are achieved by a thread guide unit for circular knitting machines formed by two parts, of which one part constitutes the fixed framework and the other part constitutes the mobile equipment, and in which fast with one of said parts there is a plurality of bobbins for feeding the thread guide unit with a plurality of threads, while the other of said parts carries the members for the formation at each turn of the rotating equipment of the successive rows of knitting; said thread guide unit being characterized in that it is associated to one of said parts and comprises: a drum member oscillating about its own axis against the action of spring means, and provided with parallel grooves or guides along its generatrixes, said guides being designed to slidably house respective thread guides fed by said bobbins and provided with a ridge radial to said drum, the ridges of all the thread guides being arranged to follow one another along at least a co-axial circumferential arc of said drum; a step cam circumscribing the drum for an are at least equal to said co-axial circumferential arc and fast with said drum, said step cam defining steps which are at least equal in number to the number of thread guides; a first slidable slide member co-operating with spring means and arranged inside a guide which is fixed with respect to said drum and parallel to the axis of said drum, said slide member being arranged to engage, during its downward movement, the ridge of the adjacent thread guide in order to cause the lowering of the latter along the respective guide and arrange the thread guide in the work position; a raising member fast with said slide member and designed to engage the ridge of the thread guide which is in the work position so as to cause, during the upward movement of said slide, the raising of said thread guide from the lowered work position; a second slidable slide member co-operating with spring means and arranged in a guide which is fixed with respect to said drum and which extends parallel to the axis of said drum, said second slide member being arranged to engage the steps of said step cam and lock the drum in the angular position in which one of the steps is locked by said second slide member; on the other part of the said circular knitting machine there being provided superposed first control members, equal in number to the number of steps of said cam and arranged to engage a respective step due to the rotation of said first or second part of the machine; second control members in phase relationship with said first control members and equal in number to the steps of said cam, said second control members being arranged to cause the disengagement of said second slide member from the step cam; and means arranged to engage said first slide member and cause the raising and lowering thereof in phase relationship with said first and second control members.

BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics and advantages will appear more clearly from the detailed description of a preferred, but not exclusive, embodiment of a thread guide unit according to the invention, in its application to a circular knitting machine of the kind in which the rotation equipment carries all the members which govern the feeding of the thread, while the fixed framework carries the members for the formation, at each turn of the rotating equipment, of the successive rows of knitting (needles and the like).

There is particularly considered a machine designed to form an open tubular fabric, that is a fabric which is made by knitting along only an arc of the circumference of the machine, so that each row of stitches begins at a generatrix of the needle cylinder of the machine and terminates at another generatrix thereof at a distance from said first generatrix equal to said arc. Machines which manufacture open tubular fabric are known, e.g. from the British Patent No. 1,000,387.

In the accompanying drawings which relate to the application of the thread guide unit to the machine of the described type:

FIG. 1 is a. perspective view of the complete thread guide unit in rest position;

FIG. 2 is an exploded view of some of the main members of the same unit;

FIG. 3 is a frontal view of the unit with a thread guide in the work position;

FIG. 4 is a partially sectioned view of the connection between the revolving drum which carries the thread guides and the fixed cover or cowling;

FIG. 5 is a cross-section of the drum which carries the thread guides;

FIG. 6 is a longitudinal section of the unit in the situation in which one thread guide is in work position;

FIG. 7 is a section similar to the preceding one when none of the thread guides are in the work position;

FIG. 8 is a plan view from below of the thread guide unit;

FIGS. 9, and 12 show cross-sectional views, similar to that of FIG. 5 of the sequence of the phases which lead to the substitution in the work position of two thread guides which follow one another in anti-clockwise direction on the drum;

FIGS. 11 and 13 show the same sequence seen frontally;

FIGS. 14, and 16 show, in front view, the sequence of the phases which lead to the substitution, in the work position, of two thread guides which follow one another in clockwise direction on the drum.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to said figures, on the rotating equipment of the machine there is provided a plurality of thread guide units arranged along its periphery. Only one of these units will be considerd. Each of said units is fed by any number of yarns coming from respective reels. In the illustrated embodiment the thread guide unit is fed by five yarns indicated at 1 which may inditferently be single or double yarns.

The thread guide unit is contained inside a cover or hood 2 fixed to the rotating equipment and internally hollow.

In the front portion of the hood member 2 projecting towards the outside of the rotating unit there is provided a front vertical milling 3 designed to act as a guide and a vertical through groove 4 which is also designed to act as a guide as will be seen hereinafter. In the upper portion of the hood 2 there is also provided a through hole which communicates with the interior of the chamber defined by the hood. Inside the hood 2 there is arranged an oscillating drum 5 which is pivoted at its top to the hood by means of the pin 6. Between the drum 5 and the fixed hood there is interposed a torsion spring 6a which tends to maintain the drum in a rest position which, in the illustrated embodiment, is achieved with an anticlock-wise rotation of the drum. On the lateral surface of the drum 5 there are provided parallel grooves. or guides 7 which extend along generatrixes of the drum and are equal in number to the threads 1 (besides a further guide, as will be seen hereinafter). Said guides 7 extend along only an arc of the drum surface. Inside each of said guides 7 there is arranged a vertically movable thread guide 8 which is provided at its upper end with a lug 9 which extends outwardly and radially to the drum.

In the upper portion of the drum 5, adjacent each of the thread guides there are secured pairs of resilient 4 springs 9a which are spreadable. These springs 9a are designed to retain each thread guide in the raised rest position by acting as pincers which are inserted in grooves 911 provided on the two sides of each thread guide.

Consequently, when a thread guide has to be lowered the initial resistance of the springs 9a is overcome and the springs are forced to open and reclose on the grooves 911.

In the first guide 4 (which together with the second guide 3 is protected and closed by a plate 2a) there is guided a rod-like conveyor element or first slide member 10 for the thread guides. Said element 10 is provided on its outside with a pin tooth 11 which projects radially from the groove 12 of the plate 2a, and is provided on its inside with a snug 12a, and a ring are or raising member 13 which is arranged below the snug 12a and is spaced therefrom by a portion slightly greater in height than the lugs 9 of the thread guides 8. The conveyor 10 is normally maintained in the lowest or working position of its run along the guide 4 by the action of a lever 14 fulcrumed in 15 to the hood 2 and loaded by a spring 16. In such manner the lever, with its end roller 17, normally urges the upper end of the slide member 10 downwards (FIG. 6). The upper position, shown in FIG. 7, corresponds to the rest position of the thread guide. From said rest position the slide member 10 is brought into the working position in the manner described hereinafter.

The vertical stroke of the conveyor 10 is limited to the support which the ridge 8a of the thread guide finds with the sector 41 which surrounds all the zone of the drum in which the thread guides are arranged. To the lower portion of the cylindrical drum 5 there is secured a step cam member 18 which substantially comprises a plurality of descending steps 19 which cover the drum for a distance approximately equal to the length of the arcuate surface along which the guides 7 of the thread guides are arranged. The step cam 18, that is, oscillates fast with the drum 5. More precisely the step cam 18 is secured to the sector 41 which is secured to the drum 5.

In the second guide 3 there is slidably arranged a second rod-like slide member 20* which projects downwardly from said guide and engages the steps 19' of the cam 18. The slide member 20 is provided with a lower end 24 extending inwardly and radially to the drum 5 and defining a means for engaging the steps 19 aligned with the trajectory of the slide 20 (the maximum stroke of the slide member 20 is limited by the length of a slot 21 provided in the plate 2a and in which the pin tooth 22 secured to the element 20 slides). The element 20, which is thus designed to act as a stop latch for the step cam 18, is maintained urged downwards by the compressed spring 23.

Until now the members fast with the rotating equipment of the machine and mobile with respect to the fixed framework have been described. There will now be described the control means acting on the various parts of the thread guide unit, such means being arranged on said fixed framework.

Such means comprise a certain number of superposed latches which are generally indicated at 25. Their number is equal to that of the steps 19 of the cam 18. They are arranged superposed one above another and are displaceable from a retracted position in which they do not extend along the path of any member carried by the ro tating equipment to a second work position. In this work position, which they reach due to displacement towards the inside of the machine, they control certain members of the unit. More precisely, the latches 25 define a plurality of control means including a first portion 27, and a second portion 26 respectively, said second portion forming an extension of the first portion. The extension 27 of each latch is downwardly inclined from an upper end to a lower end to a level corresponding to that in which the tooth 24 of the slide 20 is carried when the latter engages the lowest step of the cam 18. In the Working position (latch projecting towards the inside of the machine) the position of the portion 26 is such as to be, with a lateral projection thereof, in the path of the step cam 18 during its rotational movement fast with the rotating equipment. In analogous manner the position of the extension 27 of each latch is such as to be in the path of the tooth 24. The selection of the latch which must be displaced from the rest position to the work position is given by a suitable control apparatus, not shown, and controlled, for example, by a program tape. Besides said latclies, on the fixed framework of the machine, adjacent the peripherally extending zone thereof in which the substitution of one thread guide with another must take place, there is provided a pair of flat inclined earns 28 and 29 which, in rest conditions, do not lie in the path of the members fast with the rotating equipment but which move, in work conditions, so as to reach the path of the lug 11 of the conveyor 10. In such manner the cam 28, the operative position of which is shown in FIG. 6, is designed. assuming that the rotating equipment moves in anti-clockwise direction, to raise the conveyor which is then re-lowered when the lug or snug 11 slides downwards on the cam 29, the operative position of which is shown in dotted lines in FIG. 7.

There will now be described in detail a single thread guide 8. The thread guide 8 is fast with a resilient lamina 30 which is secured at its upper end 31 to the thread guide. Said lamina is normally maintained resting on the body of the thread guide and acts as a thread braking pincer designed to retain near its lower end the end of the thread when it is cut adjacent the end selvage of the fabric. The pincer must re-open adjacent the front selvage of the fabric in order not to obstruct the free advancement of the thread during the formation of the knitwear. For such purpose rods 32 (equal in number to that of the thread guides) are arranged radially to cross the body of the drum '5 at the side of each thread guides and to push end-wise against the laminas 30. Said rods 32 are arranged, in rest conditions, as illustrated in FIG. 7 by means of compressed springs 33. In this position a respective ridge 32a of each stem 32 abuts against a plate 32b. The end of the rod relative to that of the thread guide which is arranged in the work position (and that is in front of the conveyor 10) is urged by a bell-crank lever 34 which is pivotable about its pivot axis 35 which secures it to the rotating equipment. Again secured to the rotating equipment there is provided a fixed sleeve 36 in which a hollow piston 37 slides. Between the horizontal arm of the lever 34 and the piston 37 there is interposed a spring 38 while on the outside of the piston there is provided a step 39 designed to co-operate with the tooth 40 which projects inwardly from the vertical portion of the lever 34. The lever member 34 can thus pass from the position shown in FIG. 6 to that shown in FIG. 7, which corresponds tothe open and closed positions of the pincers, respectively. In fact, twoseparate control members (not shown) are provided which are designed to act, when a change of thread is requested, along the arrows F1 "and F2, respectively, on the piston 37 so that it slides upwardly and on the base of the lever 34 causing the latter to move outwards, radially with respect to the machine. Due to the control along F1 of the piston, the tooth 40 zengages beneath the step 39 and raises the stem 32 considered into the retracted position, while under the action of the force F2 the tooth 40 frees the step 39 and permits the lowering of the piston 37 under the action of the spring 38, so that the stern once again projects. Advantageously the lever 34 engages the stem 32 by means of a curved profile 34a which is designed to also act as a support surface for the ends of the various rods 32 during the rotation of the drum 5.

In this case the actions F1 and F2 cause the simultaneous retraction and projection of more than one stem 32 but not of all (see FIG. 8), and therefore the closure and the opening of the corresponding pincers or laminas 30. The opening occurs to a different extent for each of said pincers because of the shape of the profile (see FIGS. 2 and 8). Finally, 41 indicates a seal sheath for the thread guides which is fast with the drum.

The working of the thread guide unit according to the invention is as follows.

It is supposed that at the end of the formation of a row of the knitting, there is programmed in the machine a change of the thread employed in the formation of the knitting, and, that is, a replacement of the thread guide in operation with another thread guide which clock-wise follows the former in clock-wise direction along the skirt of the drum. In relation to this, from the unit of latches 25 projects the latch corresponding to the new thread guide to be utilized.

Due to the interrupted rotation of the rotating equipment (which is, as stated, anti-clockwise), the end of the extension 27 is engaged (FIG. 14) by the end 24 of the slide 20, which moves along the inclined plane of said extension 27 so that the slide 20 rises to the highest level of said plane. With the progressive raising of the slide 20, and therefore with the disengagement of the slide 20 from the step which previously retained it, the drum is caused by the spring 6a to rotate in anti-clockwise direction until a new step 18 is positioned below the now raised sh-de 2U. Continuing the raising of the slide 20, the drum continues to rotate step-wise until a further rotation of the step cam and the drum fast therewith is stopped by the final engagement between said slide and the underlying step (FIGS. 15 and 16). In this position the new thread guide is carried exactly adjacent the slide or conveyor 10.

There is thereby obtained the passage from one thread guide to the other, the two thread guides following each other in clockwise direction along the guides of the drum. In the case in which the substitution must take place between two thread guides which follow each other in anticlockwise direction on the drum (for example starting from the position of FIGS. 9, 11), the rotation of the corresponding step cam is caused by a respective latch 25 whose portion 26 extends along the path of the step cam 18 and engages the step which passes adjacent the line of action of the latch (FIG. 10) and causes the rotation of the cam in clockwise direction against the action of the spring 6a until, by rotating the mobile equipment, the step passes tangentially out of the zone of engagement with the latch (FIG. 12). correspondingly the slide 20 is lowered along the steps under the thrust of the compressed spring 23. When said step is no longer pushed by the latch, the tooth of the slide 20 locks the drum in the angular position reached at that moment.

It will be understood that, when the actuation of the thread guides involves different thread guides, as it occurs above with regard to FIGS. 9, l0, 12, the latches involved are different, however, when one and the same thread guide is involved the actuating latch is always one and the same. In fact the latch 25 used in the above described case, in which the portion 26 engages the steps 19 of the drum 5, is the same as the latch 25 used in the first case explained previously, in which the portion 27 engages the slide member 20, when the same step 19 has to be finally engaged by the slide member 20. In other words each step 19 (or each thread guide) has its own latch and the same latch is used both when the drum has to be oscillated in clockwise and anti-clockwise direction to reach the same final position.

The operation of substitution of the thread guide in the above-described Work position is preceded by the raising the conveyor, guided by the inclined cam 28, rises and the tooth 12a and ring 13' entrains upwards the thread guide which has ceased working. There then takes place the above-described switching operation, so that the new thread guide is arranged adjacent the conveyor 10, with the respective lug 9 arranged below the extension 12a of the conveyor. At the end of the switching, the snug 11 slides along the downward incline of the cam 29 which pushes the conveyor 10 and consequently the new thread guide into the work position. Before these operations there takes place the closure of the lamina 30 of the previously described thread braking pincers. After the substitution of the thread guide the lamina 30 is opened and the relative thread is freed.

It should be noted that two conjointly controlled thread guides may be arranged in a single guide 7 of the drum. Moreover, advantageously the angular positions which the drum can assume are one greater than the number of thread guides operating; that is to say that a supplementary groove 41a is provided without a thread guide and, in relation thereto, a supplementary step in the cam 18. This is in order to be able to interrupt every feeding of thread from the thread guide unit under consideration, during one or more turns of formation of the knitting. This occurs due to the fact that in front of the slidable conveyor 10 there is arranged precisely the groove 410, so that, during the lowering of the conveyor, the tooth 12a slides freely in the groove 41a without causing the lowering of any thread guide (note FIG.

It may also be noted that the presence of the half-ring 13 constitutes a safety measure in case of the accidental lowering of thread guides other than those to which the selection controls are automatically imparted. As deducible from the foregoing, an accidentally lowered thread guide will be raised by the half-ring 13 at the next thread change and before the rotation of the drum 5.

We claim:

1. In a circular knitting machine having a fixed framework and a rotating equipment, a thread guide unit arranged on said rotating equipment and comprising a hood member, a drum member oscillatingly supported by said hood member, spring means provided between said hood member and said drum member for subjecting said drum member to a torque, parallel grooves distributed on the lateral surface of said drum member at least over a sector of said drum member, thread guides slidably mounted inside said grooves, to move from a rest position to a working position, a step cam circumscribing the drum for an are at least equal to said sector and defining a plurality of steps at least equal in number to the number of said grooves, a first and a second guide arranged inside said hood member substantially, parallel to the axis of oscillation of said drum member, a first and a second slide member lengthwise movable inside said first and said second guide, respectively, said first slide member having means for engaging a selected thread guide to move it from said rest position into said working position and vice versa, and said second slide member having means for engaging said steps of said step cam to lock said drum member against the torque of said spring means, a plurality of superposed control means corresponding in number to the number of said steps of said step cam and having each a working position lying in the path of said step cam and of said second slide member, respectively, to cause a rotation displacement of said drum member in the one or the other sense to selectively position a thread guide for activation by said first slide member, and means arranged in the rotation path of said first slide member for raising and lowering it in phase relationship with the operation of said control means.

2. A thread guide unit according to claim 1, wherein each said thread guide comprises an upper end provided with a lug projecting outwardly and radially to said drum member and wherein said means provided on said first slide member for engaging said thread guides comprises a raising member fast with said first slide member and shaped according to an arc of a circle engaging said lug of said thread guide from the bottom, thus raising it from said working position to said rest position, and a snug rigid with said first slide member, mounted over said raising member and spaced therefrom engaging said lug from the top, thus urging said selected thread guide from the rest position into the working position.

3. A thread guide unit according to claim 1, wherein a supplementary empty groove is provided on said drum member parallel to said grooves of said drum member; a step being provided on said step cam cooperating with said supplementary empty groove for interrupting thread feeding from the said thread guide unit of the circular knitting machine.

4. A thread guide unit according to claim 1, further having thread braking means associated to said thread guides, said thread braking means comprising a plurality of thread braking pincers equal in number to the number of the thread guides and each formed by a resilient lamina with an upper end secured to the thread guide and a lower end arranged free to clamp the thread between the associated thread guide and said lower end, a plurality of rods mounted on said drum member substantially transversely to said laminas and engaging said laminas nearthe lower end thereof, a lever means pivotally mounted'on said hood member, a curved cam means fast with said lever means for selectively engaging the rod associated with the selected thread guide, and actuating means for said lever means causing said cam means to urge said selected rod against said lamina to free the thread'braked by said lamina.

5. A thread guide unit according to claim 1, wherein said plurality of superposed control means comprises a plurality of latches arranged one over the other and having each an inclined portion extending between a lower and an upper end thereof, said lower and said upper ends and said inclined portion lying in said working position in the path of said means of said second slide member engaging said steps of said step cam for disengaging said second slide member from one of said steps and engaging with another of said steps after a rotation displacement of said drum member due to said spring means.

6. A thread guide unit according to claim 1, wherein said plurality of superposed control means comprises a plurality of latches arranged one over the other and having each a lateral projection lying in said working position in the rotation path of one of said steps of said step cam, thus causing the engagement of the relative latch .with said step and a rotation displacement of said drum member against the action of said spring means and locking of said drum member by said second slide member'in another position.

References Cited UNITED STATES PATENTS 971,986 10/1910 Gee 66l39 2,961,857 11/1960 Green 66138 X 3,521,466 7/1970 Tannert 6619 FOREIGN PATENTS 402 1876 Great Britain 6 ,6l39

ROBERT R. MACKEY, Primary Examiner U.S. Cl. X.R. 66-139

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