Creel for circular knitting machines

The frame of a creel includes vertical support columns rigidly interconnected at their upper ends by a framework arranged so as to permit the frame to be positioned astride a circular-knitting machine with the columns disposed around the machine itself and with the framework at a height such as not to interfere with the movement of personnel about the machine. A vertically-movable slide is associated with each column, the slides being rigidly interconnected by a peripheral bobbin-carrier support structure. A driving device is provided for raising and lowering all the slides in unison in order to raise the peripheral structure to an upper position at a height at which it does not interfere with the movement of personnel about the machine and to lower it, respectively, to a lower position in which the structure surrounds the machine and is located at a height such as to allow manual access to bobbins which are on the bobbin-carrier.

The present invention relates to creels for supplying yarn to the yarn 
feeds of knitting machines and relates in particular to a creel for 
circular knitting machines, of the type comprising a frame which carries 
at least one horizontal row of bobbin carriers. 
Modern circular knitting machines are being constructed with ever greater 
numbers of systems or yarn feeds for increasing the productivity of the 
machine, and consequently require an ever greater number of bobbins. 
Moreover, the need to reduce to a minimum the frequency at which the 
bobbins are replaced leads to the adoption of ever larger and heavier 
bobbins, as well as to an ever greater use of the so-called "head-to-tail" 
system in which each fall has a corresponding pair of adjacent bobbins, 
and in which the tail end of the yarn of one of the bobbins is connected 
to the leading end of the yarn on the other bobbin. The "head-to-tail" 
system allows bobbins to be changed without the machine ever being stopped 
since, whilst one bobbin of each pair is in use, being unwound, an 
operator can replace the empty bobbin with a new one. 
The main result of the increase in the number and weight of the bobbins is 
that the bobbin-carrier becomes loaded with very considerable weights. For 
example, a machine with 72 yarn feeds (and machines exist with even 96, 
120 and more yarn feeds) requires 144 bobbins. If bobbins of 3 kg are used 
(and bobbins of even 5 Kg exist) the weight carried by the bobbin carrier 
exceeds 400 kg. 
In normal machines, in which the bobbin carriers are supported by an upper 
annular structure carried in its turn by the frame of the machine, the 
significant weight of the bobbins is borne directly by the machine itself 
causing deformation of the frame to the detriment of the centring of the 
machine. Since the bobbins must be located at a height of at least 1.80 m 
to permit free access to the zone immediately surrounding the machine, 
their replacement becomes rather inconvenient and tiring, especially if 
the bobbins are arranged in different concentric circles with rather 
limited spaced between them. 
The said disadvantages, that is to say the excessive weight carried on the 
machine and the difficulty of replacement of the reels, are eliminated by 
the use of side-creels, which can be of various types. side creels, which 
are units entirely separate from the machine, have, however, other 
disadvantages of greater or lesser importance. The first of these is their 
bulk since the creels occupy a significant floor space on two sides of the 
machine. Since they are also loaded from their outer side with respect to 
the machine it is also necessary to leave a free corridor between one row 
of creels associated with one machine and a parallel row of creels 
associated with an adjacent machine. 
Even modular creels, which are disposed around the machine, have 
significant bulk and constitute a considerable inconvenience for the 
associated personnel. 
A second characteristic disadvantage of side creels is the notable 
difference in the distances between the upper most central bobbins and the 
lower side bobbins. This difference in distance affects the tension of the 
threads. In this connection it should be mentioned that the thread guides, 
that is, the points of introduction of the threads into the machine, are 
disposed in a circle, whilst the bobbins are arranged in lines at 
different heights and distances. 
A third disadvantage lies in the fact that, in side creels, the bobbins are 
oriented with their axes horizontal so that the threads must undergo a 
change of direction 90.degree. more than in the vertical axis arrangement 
characteristic of conventional reel carriers supported directly by the 
machine frame. 
The object of the present invention is to eliminate all the said 
disadvantages. 
To achieve this object, according to the present invention, there is 
proposed a creel of the type mentioned at the beginning, characterised in 
that the frame comprises vertical support columns rigidly interconnected 
at their upper ends by a framework arranged so as to allow the framework 
to be positioned astride the machine with the columns disposed about the 
machine itself and with the framework at a height such as not to interfere 
with the movement of personnel about the machine. A vertically-movable 
slide is associated with each column with the slides being rigidly 
inter-connected by a peripheral bobbin carrier support structure. Means 
are provided for driving raising and lowering movements of all the slides, 
in unison, in order to raise the peripheral structure respectively to an 
upper position at a height at which it does not interfere with the 
movement of personnel about the machine, and to lower it to a lower 
position in which the said structure surrounds the machine and is located 
at a height such as to allow manual access to the bobbins which are on the 
bobbin carriers. 
In a creel according to the invention, the weight of the bobbins assembled 
in one set, or preferably several sets, around the peripheral structure 
does not bear on the machine. However the set or sets of bobbins are 
located entirely around the upper part of the machine, that is to say, 
their disposition is analogous to that of bobbins carried directly by the 
machine itself. By this arrangement the disadvantage of side creels, that 
is, differences in the distances between the bobbins and the thread guides 
of the machine, is eliminated. 
The bobbin carriers can advantageously be mounted on the peripheral support 
structure in such a way that the axes of the bobbins are substantially 
vertical, as in the case of reels carried directly of the machine, so that 
the said supplementary change in direction of the threads, by 90.degree. 
characteristic of conventional side creels, is eliminated. 
Finally, perhaps the most important advantage of a creel according to the 
invention is that, in normal working conditions, all the equipment 
comprising the peripheral structure with its bobbins is located in an 
elevated position and the only obstacles around the machine are the 
columns. The bulk of these columns can be made entirely negligible since 
these columns can be very slender. 
The possibility of lowering the said equipment when it is necessary to 
change the bobbins offers the further advantage that the bobbin can be 
lowered into a machine operator's reach without the operator having to 
mount a ladder, platform or the like. Moreover, since the lowering and 
raising of the bobbins causes merely an elongation and shortening of 
thread paths, and does not obstruct them in any way, the bobbins can, to 
advantage, be replaced without the machine being stopped and, hence, 
without any down time in the working of the machine.

In FIG. 1 there is schematically shown, in broken lines, a circular 
knitting machine generally indicated M, which includes, among other 
things, a frame I which supports, by means of vertical rods A, a system of 
annular rails R. The rails R, in turn, carry sets of thread tensioners 
(not shown). 
Referring to FIGS. 1 to 4, a creel formed as a preferred embodiment of the 
invention includes a set of three vertical support columns 10 disposed at 
the edges of an equilateral-triangular prism. The columns 10 are 
constituted by slender tubular-metal elements having, for example, a 
diameter of the order 80 mm. Each column 10 is provided at its lower end 
with a ground-engaging foot 12. 
The upper ends of the columns 10 are rigidly interconnected by a triangular 
framework 14 which comprises, among other things, a set of three 
horizontal box section beams 16, disposed along the sides of an 
equilateral triangle. Each pair of beams 16 is connected to a column 10 by 
means of a box-like connection plate. Two of these connection plates have 
been indicated by 18 in FIGS. 1 and 3, whilst the third connection plate, 
of different configuration, has been indicated by 19 in FIGS. 1 and 3 for 
reasons which will become apparent below. 
The structure including the columns 10 and the framework 14 is intended to 
be positioned astride the machine M, as illustrated in FIG. 1. 
As will readily be understood, the columns 10 constitute the only elements 
of the creel which occupy any floor space. This space is very little since 
the three columns 10 can be very slender, having a diameter of the order 
mentioned above. The height, or vertical length, of the columns is such 
that the framework 14 is located at a height such as not to interfere with 
the movement of personnel about the machine M. 
Each column 10 is provided with a slide 20 constituted by a tubular metal 
sleeve, vertically movable along the column itself. 
The sleeves or slides 20 are rigidly interconnected by a peripheral bobbin 
carrier support structure generally indicated 22. The structure 22 
comprises, among other things, a pair of concentric circular rails 24, 
fixed to the sleeves 20 and located one above the other. 
The rails 24 carry, in their turn, respective sets of rod-like arms 26 
which project radially outwardly from the rails themselves. Each arm 26 
carries a pair of adjacent bobbin carriers 28 which are radially spaced. 
The preferred arrangement, shown in FIGS. 1 and 4, includes two 
vertically-spaced circular horizontal rows of bobbin-carrier pairs 28, the 
rows being arranged around the knitting machine. The bobbin carriers of 
each pair are radially adjacent to allow them to carry a pair of bobbins B 
usable alternately to supply one of the yarn feeds of the machine M 
according to the so-called "head-to-tail" system. 
The said arrangement is not the only one possible, however, since it would 
also be possible to have more than two vertically-spaced circular 
horizontal rows of bobbin-carrier pairs arranged around a machine having a 
higher number of yarn feeds, or even a single row arranged around a 
machine having fewer yarn feeds. 
In the illustrated arrangement, in which there are two vertically-spaced 
circular rails 24, the upper rail 24 carries, by means of rod-like 
brackets 30, a further circular rail 32 which, in turn, carries thread 
guides 34 through which pass the threads of the bobbins B before passing 
to the thread tensioners (not shown) carried by the uppermost rail R of 
the machine M. 
The peripheral structure 22 is intended to be located normally at a height 
above that of a tall person. For example, the height H (FIG. 4) of the 
lower rail 24 from the ground may, in normal working conditions, be of the 
order of slightly more than 1.80 m. In this arrangement the bobbins B of 
the two vertically-spaced rows are practically inaccessible to a person 
standing on the ground, but no part of the peripheral structure 22 
constitutes an obstruction to movement and to the working space around the 
machine M. 
The creel is provided with means for driving the raising and lowering 
movements of all the sleeves 20 in unison in order to displace the 
peripheral structure 22 between the normal raised position, corresponding 
to the height H, and a lowered position, in which the same structure 22 
surrounds the machine M and is located at a height such as to allow manual 
access to the bobbins B for the purpose of replacing these bobbins. 
In FIG. 4 the raised position of the structure 22 has been shown in 
continuous lines whilst the lowered position has been shown in broken 
lines. In this latter position the lower rail 24 is located at a height h 
above the ground which is preferably of the order of 1.30 m. In these 
conditions the bobbins B of the lower row are located at about the height 
of the shoulder of a short operator, whilst the bobbins B of the upper row 
are located at head-height or slightly higher, and can also be reached by 
hand. 
The preferred drive means for raising and lowering the movable members 
which make up the structure 22 will now be described with reference to 
FIGS. 1, 2 and 3. 
In each tubular column 10 is rotatably, but not slidably, mounted a 
vertical threaded shaft 36. Each column 10 has, outwardly with respect to 
the frame, a vertical slit 37 over which extends a fillet 40 rigidly 
connected to the respective sleeve 20 by screws 42. The screws extend 
through the slit 37 into nut 44 and constitute members for rigidly fixing 
the respective sleeve 20 to a nut 44 slidably mounted within the column 
10. A key member 45 is clamped by the screws 42 between the fillet 40 and 
the nut 44. The key member 45 is slidably engaged in the slit as an aid to 
prevent the nut from rotating. Each nut 44 is threadedly engaged with the 
threaded part of the respective shaft 36. 
On the upper end of each shaft 36 there is keyed a respective toothed chain 
sprocket wheel 38. The sprocket wheels 38 are located within the 
respective box-like connector plates 18, 19 and their common generally 
horizontal plane is located at a mid level of the cavities of the box 
beams 16. The sprocket wheels 38 are interconnected by an endless 
transmission chain 41 the arms of which extend within the box beams 16 
where they are supported by shoes such as 43 (FIG. 2) of material having a 
low coefficient of friction, such as polytetrafluroethylene or polyamide. 
Within the box-like connector plate 19 there is also located a chain 
tensioner system which comprises a pair of sprocket wheels 45 and 46. The 
position of the sprocket wheel 45 is adjustable to adjust the tension of 
the chain 41. 
As will be understood, the threaded shafts 36 and hence the nuts 44 and the 
three sleeves or slides 20 are interconnected by the chain 41 in such a 
way as to perform identical and simultaneous movements. 
One of the threaded shafts 36 (that on the left in FIGS. 2 and 3) is 
extended upwardly and constitutes the output shaft of a worm screw 
reduction gear box 48. The reduction gear box 48 is carried by the 
box-like connection plate 19 and in turn carries a flanged reversible 
electric motor 50. 
The motor 50, as will be understood, serves to drive the lowering and 
raising of all the movable members which make up the peripheral framework 
22 carrying the bobbins B. 
The upper and lower limits of the course of movement of the assembly, 
corresponding respectively to the heights H and h (FIG. 4) are defined by 
end-of-course switches. These switches are indicated by 52 and 54 in FIG. 
2 and are rigidly connected to the connection plate 19, that is to say to 
the fixed frame-work 14. 
The switches 52 and 54, which are of the push-button type, have associated 
therewith a vertical shaft 56 adapted to be displaced vertically but held 
in a fixed, unstable position by the force of two opposing springs 58. A 
striker lug 60 carried by the left hand sleeve 20 (FIG. 2) slides 
vertically on the shaft 56. 
Above and below the lug 60 the shaft 56 carries two collars 62 and 64 the 
positions of which are adjustable along the length of the shaft itself. 
The shaft 56 also carries, adjacent the push-buttons 52 and 54, an 
olive-shaped cam 66 able to cooperate with these push-buttons. When, 
during a descending movement of the movable assembly, the striker lug 60 
strikes the lower collar 64, the shaft 56 is thrust downwardly so that the 
cam 66 engages the push-button of the switch 54 stopping the assembly in 
the lowered position. 
Similarly, on raising of the assembly, when the striker lug 60 engages the 
upper collar 62, the shaft 56 is thrust upwardly and the cam 66 engages 
the push-button 52 thus stopping the assembly in the raised position. 
The lowering and raising of the movable assembly and of the bobbins B, 
whilst the machine M is in operation, merely lengthens or shortens the 
path of the threads which are being unwound from the bobbins B, leaving 
the threads themselves still with the correct tension for knitting. This 
allows the replacement of the bobbins B without the machine being stopped. 
If the raising movement were to take place with the machine stopped, the 
threads of the various yarn feeds could become entangled. To avoid this 
inconvenience, a gating system is interposed in the electrical control 
circuit for the motor 50 which prevents the raising of the movable 
assembly when the machine M is not working. 
The main advantages of a creel according to the invention have already been 
mentioned in the introduction. A further advantage of the arrangement 
illustrated lies in the fact that, by adequately dimensioning the circle 
on which the bobbins B lie, that is the diameter of the rails 24 and of 
the cylinder in which the axes of the columns 10 lie, it is possible to 
leave sufficient space between the rails 24 and the machine M, when the 
bobbins B are in the lowered position, for the innermost bobbins to be 
replaced by an operator positioned between the rails 24 and the machine M 
with greater ease than if the operator had to replace the innermost 
bobbins from an outer position. This characteristic is on the other hand 
also allowed by the fact that the diameter of the circle on which the 
innermost reels B lie is not limited by considerations of size, given 
that, in normal operation, the whole of the movable assembly is located at 
a height at which it does not interfere with the movement of personnel 
about the machine. 
Naturally, the creel is susceptible of different variations within the same 
principle of the invention. Thus, the slides associated with the columns 
could have a different configuration from the sleeves and also the drive 
means for their movement could be different from the screw and nut system 
illustrated. Thus also, the reversible electric motor 50 could be replaced 
by a source of movement of different type, such as for example an 
hydraulic motor.