Yarn feeding apparatus for multi-feed knitting machines

The apparatus comprises a support on which a rotatable wheel is mounted an area of the cylindrical surface whereof is in contact with a belt effective to press a yarn thereon which is led through an eye carried on an inlet arm and, respectively, through an eye carried on a yarn outlet arm, such arms being movable between a position whereat they hold the yarn in the nip between the belt and wheel, and a position whereat they hold the yarn out of contact with the belt. The inlet arm is positioned and dimensioned such that, in the condition whereby it holds the yarn inoperative, that is out of contact with the belt, the eye carried thereon is shifted to the opposite side of said belt relatively to a plane led through the longitudinal side edge of the belt lying closer to the eye; whereas, in the operative condition, the inlet arm eye is shifted to the same side of the belt relatively to said plane. Further, the inlet arm eye is located between the belt-to-wheel contact area and a fixed inlet eye which is in substantial alignment with the inlet arm eye, in the condition whereby it is at a position with the yarn inoperative, and the adjacent belt edge.

BACKGROUND OF THE INVENTION 
This invention relates to a yarn feeding apparatus for multi-feed knitting 
machines, in particular circular knitting machines. 
It is known that with multi-feed knitting machines, i.e. machines whereon a 
knitted fabric is formed by means of needles arranged to pick up plural 
feed yarns from a number of cops, reels, or the like, the yarns are picked 
up from said cops or reels and fed to the needles through feed 
apparatuses, comprising each a wheel set for free rotation about its own 
axis and having a substantially cylindrical shaped surface whereon a yarn 
can be pressed and held by a belt having a smaller height than the wheel 
driven through a motor means. The belt movement causes the wheel to rotate 
and entrain the yarn from a respective cop, said yarn being accordingly 
fed at a preset rate to the respective needles, whereto it is released 
from the belt and wheel. 
In the instance of circular knitting machines, wheels of this type are 
arranged in a circle at the machine top and the belt which drives them 
rotatively is a single closed loop configuration. 
Feed apparatuses of the wheel type as outlined above are described, for 
example, in German Pat. Nos. 1 585 298 and 1 635 893. 
It is a known fact that it is often necessary to take one or more yarns out 
of contact with the belt, by shifting the yarn in question along the wheel 
axis direction, to one side of the cited belt; the yarn is allowed to slip 
over the surface of the wheel which continues to be rotated by the belt no 
longer acting, however, on the yarn. This occurs, for example, when the 
stitch length of the knitting machine is to be changed, or when the type 
of fabric knitted on the machine is to be changed, or when a knitwork is 
to be produced which has stripes of different colors and one or more yarns 
of a given color must be left out of the knitwork being knitted. 
Owing to the knitting machines being operated at a high speed, where it 
becomes necessary to discontinue the feeding of a given yarn, the yarn in 
question has to be removed very quickly from its position in the nip 
between the belt and related wheel. Each yarn feeding apparatus is 
provided with a movable yarn inlet arm which is guided to and from the 
contact area between the belt and wheel, and with a movable outlet arm on 
which the yarn leaving the apparatus is passed; this outlet arm is 
responsive to the tension of the outgoing yarn, thereby lowering the 
tension on the outgoing yarn results in a decrease of the pressure applied 
on said arm, which acts mechanically or otherwise on the inlet arm or 
feeding finger, which moves up and takes the yarn out of the pressure area 
of the belt onto the wheel. The movable outlet arm which is somewhat 
longer than the yarn inlet arm, and the yarn trained over the cited wheel 
is moved and guided through two eyes, made each rigid with each of the 
arms. The two arms are rigid with each other by the provision of a 
rotatable shaft carried on the wheel holder; as the yarn is being picked 
up, both arms are shifted toward the belt so as to retain the yarn under 
the belt in a substantially longitudinal attitude with respect to the 
belt. When the feeding of said yarn is to be discontinued, the 
displacement of the two arms pulls the yarn out of contact with the belt 
and respective wheel. As mentioned, feed apparatuses of this type are well 
known and are described, for example, in German Pat. Nos. 1,585,298 and 
1,635,893; however, they have the disadvantage of requiring a 
comparatively long time from the moment when the movable outlet arm acts 
on the movable inlet arm to shift the yarn laterally with respect to the 
belt. That time period is governed by the time required, consequently for 
the displacement and bias force transmitted by the outlet arm, for the 
inlet arm to move from the inoperative position into the operative one, 
and viceversa, to move the oncoming yarn to the apparatus from out of 
contact into the nip under the belt, where it is held pressed against the 
wheel. In other words, the time involved to take the yarn into the nip 
between the belt and wheel or move it out of that position, will depend on 
the effort to be exerted on the yarn by the inlet arm and on the angle 
wherethrough said arm is to be moved. 
With conventional appratuses, the yarn is led to the eye of the inlet arm 
from a substantially parallel direction to the wheel axis, so that the 
inlet arm must increase or reduce the amount of yarn picked up therfrom 
whenever its attitude is to be changed; since the oncoming yarn to the 
apparatus always tends to apply a pull on the arm with a significant force 
toward the point where the yarn comes from, it follows that the rotational 
movement is considerably hindered by the action exerted thereon by the 
yarn, the arm thus inducing a significant variation in the amount of yarn 
being fed during the arm moving step. This results in a decrease of the 
apparatus responsiveness to variations in the pressure exerted by the 
outgoing yarn on the outlet arm, and hence a relatively low readiness of 
the apparatus to react to the requirement of changing the yarn feeding 
conditions or stopping altogether. 
Moreover, with conventional apparatuses, the yarn inlet arm is always 
located in the proximity of the adjacent belt free edge, whereas to cause 
the apparatus to put the yarn into and out of feed, a shaped member is 
provided having a sloping surface over which the oncoming yarn to the 
apparatus is caused to slide, it moving outward, and respectively under, 
the contact area between the belt and wheel. 
This arrangement for moving the yarn out of knitting, or respectively into 
knitting, namely for feeding it to the opening machine or viceversa, is a 
time consuming one which does not allow the yarn feeding to the knitting 
machine to be discontinued or, respectively, initiated at the high rate 
which would instead be desirable. 
SUMMARY OF THE INVENTION 
It is a primary object of this invention to provide an improved yarn 
feeding apparatus, wherein the time required to discontinue the yarn 
feeding and resume it can be extremely short, and wherein that operation 
can be controlled by exerting but a minimal effort on the yarn outlet arm 
for the yarn being fed into the knitting machine. 
A further object of the invention is to provide such an apparatus, whose 
operation is purely mechanical and, hence, of simple construction and low 
manufacturing cost. 
These and other objects are achieved by a yarn feeding apparatus comprising 
a wheel mounted for idle rotation on a rigid support attachable to a 
knitting machine and having a plurality of pegs distributed over a 
cylindrical surface coaxial with said wheel, over an arc of said surface 
there being trained a belt whose height is lower than the height of said 
pegs, mounted on said rigid support there being a rotatable shaft 
extending perpendicularly to the wheel axis and having two oscillating 
arms keyed thereto, said oscillating arms projecting from two 
diametrically opposed sides of said wheel and carrying at the free ends 
thereof an eye or shaped element to let the yarn through, a yarn inlet arm 
being proximate to the area whereat said belt contacts said wheel, and a 
yarn outlet arm being proximate to the area whereat said belt separates 
from said wheel, said arms being arranged to oscillate from an inoperative 
position wherein the yarn is held out of contact with said belt and the 
eye of said yarn inlet arm is shifted to the opposite side of said belt 
with respect to a plane containing the longitudinal side edge of said belt 
lying closer to said eye and an operative position wherein the yarn is 
held level with said belt and the yarn inlet arm eye is shifted toward 
said belt, the apparatus being characterized in that said yarn inlet arm 
has a length dimension whereby, in said operative position, the yarn inlet 
arm eye is shifted to the same side of said belt relatively to said plane 
containing the longitudinal side edge of said belt, and that said rigid 
support is made integral with a fixed inlet eye wherethrough there is 
passed the yarn being fed to the eye of said yarn inlet arm which is 
located between said fixed eye and said belt, said fixed inlet eye being 
positioned in the proximity of said plane containing the belt longitudinal 
edge and substantially aligned with the adjacent longitudinal side edge of 
said belt and with the eye of said yarn inlet arm in the inoperative 
position thereof.

DESCRIPTION OF A PREFERRED EMBODIMENT 
This apparatus, as shown in the drawing figures, comprises a rigid support 
1 attachable to the frame of a knitting machine and having, mounted 
thereon for idle rotation about its axis, a small wheel 2 which has a 
cylindrical surface bordered by an array of pegs 3, as clearly shown in 
the drawings. In use, over an arc of the wheel cylindrical surface, there 
is trained in pressing relationship a belt 4 whose height is smaller than 
the height of the cited pegs. 
Mounted for idle rotation about its axis, lying perpendicularly to the axis 
of the wheel 2, there is on the support 1 a small shaft 50 whose two ends 
project from two diametrically opposed sides of the wheel and carry an 
oscillating inlet arm 5 and oscillating outlet arm 6, respectively, having 
each, at their free ends, an eye 7, respectively 8, through which the 
oncoming yarn and, respectively, outgoing yarn to/from the apparatus are 
passed. As shown in the drawing figures, the inlet arm 5 is located 
proximate to the area where the belt 4 contacts the wheel 2, the outlet 
arm 6 being proximate the area where the belt separates from the wheel. 
As may be seen in the figures, the inlet arm is dimensioned and positioned 
such that, in the inoperative condition when the yarn is held out of 
contact with the belt (FIGS. 1 and 2), the eye 7 is shifted to the 
opposite side of the belt 4 with respect to a plane containing that belt 
longitudinal side edge which lies closer to the eye 7. 
An essential feature of the present apparatus is that the inlet arm 5 has a 
length dimension such that, as the inlet arm is shifted into the operative 
position whereat it feeds the oncoming yarn 10 below the contact area in 
between the belt and wheel (FIGS. 3 to 5), the eye 7 of the inlet arm is 
shifted to the same side of the belt with respect to the cited plane 
conducted through the longitudinal side edge of the belt. 
A further essential feature of this apparatus is that, integral with the 
rigid support 1, is a fixed inlet eye 11 through which is passed the yarn 
from a yarn supply cop, the yarn being fed into the eye 7 of the inlet arm 
5 and the fixed inlet eye 11 being positioned in the proximity of the 
cited plane containing the longitudinal side edge of the belt. In the 
embodiment presently described, it would be located on the opposite side 
of the belt with respect to said plane. Further, the fixed eye 11 is 
substantially aligned with the belt and with the eye 7 of the inlet arm 5 
with the latter in its inoperative position shown in FIG. 1. The yarn from 
the cop supply, after passing through the fixed inlet eye 11, eye 7 of the 
inlet arm, and training over a cylindrical portion of the wheel 2, is 
passed through a fixed outlet eye 12, also made rigid with the support 1 
and located above the plane which contains the top free edge of the belt 
(relatively to FIGS. 1 to 4), to be then passed under a fixed rigid rod 13 
(FIGS. 2,4 and 5) and through the eyes 8 of the outlet arm 6. 
When the yarn 10 is not picked up by the knitting machine, a spring holds 
the two arms 5 and 6 in the raised position shown in FIGS. 1 and 2. In 
this condition, the eye 7 of the arm 5 holds the yarn 10 above the belt 4, 
thereby, even if said belt rotates the wheel 2, the yarn 10 is not picked 
up from the cop and slides over the surfaces of the pegs 3. 
It is now assumed that the yarn 10 is being picked up by the knitting 
machine: in this condition, the pull exerted on the yarn 10 will cause the 
outlet arm 6 to be lowered, which results in a counterclockwise rotation 
of the arm 5 (FIG. 3), thus causing the eye 7 to be lowered on the same 
side of the belt with respect to the plane conducted through the top edge 
of the belt. 
It may be noted that such lowering of the inlet arm is quite easily 
effected and responsive, for two essential resons, one of which is that, 
in the inoperative condition of FIG. 1, the yarn section included between 
the fixed inlet eye 11 and the area where it contacts the wheel surface, 
is substantially rectilinear, thereby the downward movement of the eye 7 
results in just a small deflection of said yarn section, and involves no 
drawing of significant amounts of yarn from the cop; the other important 
reason is that the arm 5 is dimensioned and positioned such that, while 
performing small oscillations around its own shaft (in common with the arm 
6) to move from the yarn non-knitting position (FIG. 1) into the yarn 
knitting position (FIG. 3), the eye 7 which entrains the yarn 10 is caused 
to move from a position overlying the plane through the top edge of the 
belt into a position below the arm itself, that is on the same side of 
said plane as the belt. The ease and speed at which this transfer of the 
eye 7 from one side to the other of the cited plane is effected will be 
facilitated by that, in the operative condition of FIG. 3, the arm 5 forms 
an angle other than 90.degree., preferably an angle of about 50.degree., 
with a perpendicular plane to the wheel axis. In fact, in going from the 
inoperative position of FIG. 1 to the operative one of FIG. 3, the 
vertical (relatively to the figures) component of the eye 7 displacement 
is a comparatively large one, that is, there occurs a substantial vertical 
movement of the eye 7 for even small angles of rotation of the arm 5. 
By contrast, when considering the operative condition of FIGS. 3,4 and 5, 
if the knitting machines stops picking up the yarn 10, that yarn will 
cease to exert a downward pull (relatively to the figures) on the outlet 
arm 6, which owing to the action of a spring provided within the support 
1, immediately tends to be raised upwardly into the position shown in FIG. 
1, thus causing the inlet arm 5 to rotate in a clockwise direction which, 
while performing but a small angle of rotational movement, will quickly 
move the yarn 10 upwards out of the area of contact with the belt 4, thus 
discontinuing the drawing of that yarn; this movement is facilitated by 
the yarn section included between the eye 11 and belt, which yarn section 
will urge the eye 7 upwards. 
In FIGS. 1-6, the eye 12 has been shown as fixedly attached to the support 
1. In actual practice, it could be carried on an auxiliary moving arm 60, 
FIG. 8, connected to the outlet arm 6 and such as to shift said moving eye 
to one side, or respectively to the other side, of the cited plane in the 
two different operating steps of the apparatus. Of course, the above-cited 
moving eye could also be made rigid with the outlet arm 6. The operation 
of placing the apparatus in the inoperative state is facilitated by the 
provision of the fixed outlet eye 12 which holds the yarn emerging from 
the contact area with the wheel raised upwardly, that is above the belt 4. 
If desired, a rigid shaped element 55, FIG. 7, may be made integral with 
the fixed support which would define a sloping surface toward the belt, 
intersecting the plane containing the top edge of the belt, that portion 
of the sloping surface which is closest to the belt being located on the 
same side of the belt with respect to the cited plane; said element should 
be placed between the inlet arm 5 and the belt, and is well known in the 
art, and disclosed, for example, in German Pat. Nos. 1 585 298 and 1 635 
893. 
Shown in FIG. 6 is a modified embodiment of the apparatus described above, 
in that figure all those parts which have similar constructions and 
functions to those shown in FIGS. 1 to 5 being designated for simplicity 
with the same reference numerals. 
In the apparatus of FIG. 6, there is provided a fixed bracket 20 which 
supports an inlet eye 21 which, as shown in the drawing, is arranged on 
the same side of the belt with respect to a plane conducted through the 
top longitudinal edge of the belt. It may be noted that the apparatus 
rigid support carries an elongate peg 22 which is located laterally to the 
wheel and extends parallel to the wheel axis and to the pegs 3. 
The yarn inlet arm, generally indicated at 23, has a portion 24 thereof 
shaped as a somewhat elongate slot and extending between the peg 22 and 
wheel. In FIG. 6, the yarn inlet arm has been shown in full lines in the 
inoperative position thereof, and in dash lines in the operative position, 
i.e. the position whereat the yarn (also shown by a dashed line in this 
condition) is caught between the belt and wheel and entrained by the 
latter. It may be seen that the yarn, as the arm is moved from the 
operative position into the inoperative one (and viceversa), slides along 
the elongate slot of the arm, which causes it to be shifted along the peg 
22 on which the yarn being picked up by the apparatus moves. This 
embodiment of the invention is no further described because its 
construction and mode of operation will be apparent from the foregoing 
discussion. 
The present apparatus has a purely mechanical character, a very simple and 
reliable operation mode, and is inexpensive to make, while ensuring in all 
cases a very high speed of transfer of the yarn from the knitting position 
to the non-knitting position, and viceversa, by virtue of the size and 
positioning of the inlet arm 5 and of the provision and positioning of the 
fixed inlet eye 11, which features have been duly discussed in the 
foregoing. 
It will be appreciated that the belt 4, instead of being arranged to rest 
on the lower portion of the wheel, with reference to FIGS. 1 to 4, may be 
arranged to bear on the upper portion of the wheel, in which case the arm 
5 will form, with respect to the arm 6, a larger angle than 90.degree., 
whereas in the instance illustrated in the drawings that angle is smaller 
than 45.degree., said angles being computed on the basis of the diagrams 
provided in FIGS. 1 and 3; in that case, the length of the arm should be 
adequate to permit the eye carried thereon to locate itself below a plane 
conducted through the belt free longitudinal bottom edge with the yarn in 
the non-knitting position.