Method and apparatus for transferring a loop from a selected needle to an adjacent needle for creating a decorative open work pattern

A method for creating an opening in tubular knitted fabric articles, including the steps of providing a knitting machine having a plurality of needles mounted in axial needle slots in a needle cylinder, the needles having a hook formed in a top end of a needle shank and a latch pivotally mounted on the needle shank below the hook for opening and closing the hook. A deflector is provided for deflecting a loop of yam being formed by a needle into the vertical plane of an adjacent needle. A needle is selected from which a loop is to be transferred. The loop on the selected needle is enlarged by deflecting the loop out of the vertical plane of the selected needle laterally into the vertical plane of an adjacent needle while the adjacent needle is in a lowered, non-interfering position relative to the deflected loop. The adjacent needle is moved upwardly into the enlarged loop, and the selected needle is thereafter removed from the deflected loop, whereby the loop is transferred to the adjacent needle and an opening is present in the fabric in the position of the selected needle. An apparatus for practicing the method is also disclosed and claimed.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION 
The present invention generally relates to circular knitting machines 
capable of manufacturing apparel, including hosiery and like articles. 
More particularly, the invention relates to a method and apparatus for 
transferring a loop or loop from a selected needle to an adjacent needle 
by enlarging the loop on the selected needle and then inserting the other 
needle through the enlarged loop before the selected needle releases the 
loop. The term loop is used below to define the segment of yarn being 
manipulated by the needles, but the term "stitch" can be used 
interchangeably. 
Circular knitting machines knit together multiple strands of arn into a 
tubular fabric, hosiery blank or other structure. The hosiery blank is 
then finished according to conventional processes to create finished 
hosiery articles, such as socks, hose and stockings. Such machines include 
a plurality of needles positioned in axial slots formed in an exterior 
surface of a rotatable needle cylinder. Each needle includes a shank 
having opposed ends. A hook is formed in a top end of the needle shank and 
a butt is formed in the bottom end of the needle shank. A plurality of 
sinkers are mounted in a sinker ring positioned on a top end of the needle 
cylinder such that the sinkers are alternately positioned between the 
needles. Circular knitting machines also include a feeder mechanism that 
delivers yarn onto the passing needles. The yarn forms a loop or loop 
around each needle. 
Hosiery articles with decorative patterns formed by open-work in the fabric 
created by transferred knitting loops is old and conventional. The space 
not occupied by the transferred loop creates a hole in the fabric, and the 
pattern of holes in the fabric collectively create the desired decorative 
effect. Heretofore such designs have been limited to relatively coarse 
gauge fabrics due to the difficulty in transferring very small loops 
between fine gauge needles. Thus, there is a need for a knitting machine 
and method which permits the creation of decorative open-work patterns in 
fine gauge knitted fabric, including fine gauge fashion hosiery, such as 
tights, pantyhose and similar articles. 
For example, U.S. Pat. No. 3,838,583 to Rumi et al. discloses apparatus 
which modifies a circular knitting machine so that it can create openings 
with transfer loops. The Rumi apparatus includes a dial plate 
eccentrically positioned over and internal to a needle cylinder and a 
planetary gear eccentrically positioned over and external to the needle 
cylinder. The upper surface of the dial plate is provided with a plurality 
of internal punches slidable in a radial direction, and the upper surface 
of the planetary gear is provided with a plurality of external punches 
slidable in a radial direction. The internal punches are inclined suitably 
in the direction opposite of the direction of rotation. Devices are 
provided to control the axial movement of the internal and external 
punches and cam means are provided to raise the needles to the level of 
the punches. Finally, a plurality of movable sinkers are positioned on the 
needle cylinder and each partially surround one of the needles. The 
strands of yarn loop around the needles and extend over the sinkers. 
In operation, the selectors raise a specified needle or group of needles 
past their normal working position. The loop on the needle catches on a 
needle shoulder which raises the loop above the sinker surrounding the 
needle. The sinker, which has an end hook, then advances and its hook 
enters the loop causing the loop to enlarge. Immediately afterwards, 
either of the two punches enter the loop by passing adjacent to an 
undercut in the needle. The needle is then returned to its normal position 
leaving the loop on the punch. The punch transports the loop to the 
intended needle which is raised up through the loop. That needle continues 
to rise until the loop is removed from the punch and then returns to its 
normal position. If the internal punch is used, the loop is transferred to 
the needle preceding the needle from which the loop was taken. If the 
external punch is used, the loop is transferred to the needle following 
the needle from which the loop was taken. 
The Rumi apparatus, like other existing apparatus used for transferring 
loops, first removes the loop from the selected needle and then transfers 
that loop to the following needle. This practice can only be used 
effectively on circular knitting machines operating with one hundred and 
twenty (120) needles or less because the small size of the needles and 
loops on most circular knitting machines operating more than one hundred 
and twenty (120) needles prevents the apparatus from reliably transferring 
the loop. A missed transfer creates a defect which results in a less than 
first-quality product. The missed transfer problem is naturally 
exacerbated when the diameter of the needle cylinder is decreased and/or 
the number of needles being operated is increased. 
Consequently, transfer loops cannot be reliably made on prior art fine 
gauge circular knitting machines. A need, therefore, exists for a method 
and apparatus for effectively transferring loops from a selected needle to 
an adjacent needle without dropping a loop and without creating other 
defects in hosiery articles manufactured on a circular knitting machine 
capable of creating fine gauge articles. 
SUMMARY OF THE INVENTION 
Therefore, it is an object of the invention to provide a method and 
apparatus for reliably transferring loops to create hosiery having a 
pattern of small openings which collectively create a decorative 
appearance to the fabric. Unlike existing methods and apparatus, the 
present invention enables open-work patterns to be formed in very fine 
gauge hosiery created on, for example, circular knitting machines 
operating 120 or more needles positioned on a needle cylinder having a 
diameter of 3.5 inches or less. The invention is capable of being used on 
any gauge machines with as little as 1 mm spacing between needles. 
Accordingly, a principal object of the present invention is to provide a 
method for virtually error-free transfer of a loop from a selected needle 
to a following needle on a circular knitting machine, including but not 
limited to a fine gauge circular hosiery knitting machine, such as one 
having 120 or more needles positioned on a needle cylinder having a 
diameter of 3.5 inches or less. 
A further object of the invention is to provide a method of or transferring 
a loop from a selected needle to a following needle by securing the loop 
on the following needle before the selected needle releases the loop. 
A further and more particular object of the invention is to provide a 
method and apparatus for transferring a loop from a selected needle to a 
following needle by widening the loop on the selected needle, inserting 
the following needle through the widened loop, and only then removing the 
selected needle from the widened loop thereby causing the selected needle 
to release the loop. 
Another object of the invention is to provide an apparatus for performing 
the transfer loop operation. 
Another object of the invention is to provide enlarging means and cam means 
for performing the transfer loop operation. 
Another object of the invention is to provide means for adapting a common 
circular knitting machine by inclusion of the invented apparatus to 
minimize manufacturing cost, to guarantee reliable operation, and to avoid 
the necessity of requiring operator re-training. 
The method according to the invention involves transferring a loop from a 
selected needle to a following needle during the operation of a circular 
knitting machine. As used herein, a selected needle is a needle from which 
the transfer loop is removed, and a following needle is an adjacent needle 
onto which the transfer loop is placed. It is contemplated by the present 
invention that the following needle may be either the needle immediately 
preceding the selected needle with respect to the direction of needle 
cylinder rotation or the needle immediately succeeding the selected needle 
with respect to the direction of needle cylinder rotation. 
To perform the transfer loop operation, the loop on the selected needle is 
enlarged or widened. Once the loop on the selected needle is sufficiently 
enlarged, the following needle is inserted through the enlarged loop such 
that the loop may then be secured around the following needle. Finally, 
the selected needle is removed from the enlarged loop thereby causing the 
selected needle to release the loop. As a result, the loop is completely 
transferred from the selected needle to the following needle and a 
controlled perforation is formed in the hosiery article. A pattern of 
openings may be formed in the hosiery article by selecting needles in 
accordance with a pre-determined set of instructions. 
The apparatus for performing the invented method includes means for 
enlarging the loop on the selected needle and cam means for controlling 
the movement of the needles to effectuate the transfer of the selected 
loop from the selected needle to the following needle. 
Each needle has a latch positioned below the hook. The latch pivots between 
a hook closed position in which the distal end of the latch abuts the 
distal end of the hook and a hook open position in which the latch abuts 
the shank of the needle and is distally disposed with respect to the hook. 
The hook and latch of each needle are aligned in a radially outwardly 
manner with respect to the needle cylinder. The butts formed in the bottom 
end of each needle extend radially outwardly beyond the circumference of 
the needle cylinder. The bottom end of each needle abuts a top end of a 
selector shank which is also positioned in the axial slots of the needle 
cylinder. The selector shanks each have teeth extending radially outwardly 
beyond the circumference of the needle cylinder. 
An actuator engages the teeth on the selector shanks and vertically moves 
particular needles according to a pre-programmed set of instructions. 
Typically, the actuator is controlled by a computer which repeatedly 
selects a particular group of needles to create a desired pattern of 
openings in the hosiery article being formed. 
In a preferred embodiment, the loop-enlarging means is a deflector 
integrally formed with and extending laterally from the shank of each 
needle at a location below the latch and the cam means includes an upper 
cam and a lower cam positioned adjacent the exterior surface of the needle 
cylinder. The deflectors are generally delta shaped, sharing a common edge 
with the needle shank and increasing in width from top to bottom. A distal 
region of each deflector extends beyond the plane of the following needle. 
Finally, the deflectors initially extend radially outwardly, but they then 
curve radially inwardly toward the longitudinal axis of the needle 
cylinder. A loop-retaining means, such as a catch, is preferably formed in 
the distal region of each deflector. 
The lower cam is positioned proximate to the bottom end of the needle 
cylinder. The lower cam has a gradually upwardly sloping contact surface 
for guiding the teeth of the selector shanks below the selected needles. 
Only the selected needles raised by the actuator encounter the contact 
surface of the lower cam. The lower cam raises the selected needles such 
that the butts of those needles are properly positioned with respect to 
the upper cam. 
The upper cam preferably includes three members. The first member of the 
upper cam is positioned above the lower cam and is off-set from the 
contact surface of the lower cam in the direction of needle cylinder 
rotation. The second member of the upper cam is positioned above the first 
member of the upper cam and is generally triangular in shape. The second 
member ofthe upper cam has an upwardly sloping upper contact surface for 
guiding the butts of the selected needles upwardly thereby forcing the 
selected needles to further rise. 
For simplicity of understanding, the following discussion of the operation 
of the invented apparatus describes one complete rotation of the needle 
cylinder in which only one needle is selected. There are at least three 
zones encountered by the needles during each complete revolution of the 
needle cylinder. The first zone is the loop feed zone in which the feeder 
mechanism delivers yarn onto the hooks of the needles. The last zone is 
the loop release zone. Between the loop feed zone and loop release zone is 
at least one loop transfer zone. Multiple loop transfer zones can be used 
to either create more complex patterns or transfer loops more than once. 
As the needles enter a loop transfer zone, the needles are positioned 
below their respective sinkers and the latches on the needles are in the 
hook closed position. 
In a loop transfer zone, the actuator selects a needle by engaging a tooth 
on the selector shank below that needle. The actuator raises the selector 
shank and the selected needle to a position that aligns a tooth on the 
selector shank with the contact surface of the upper cam. Consequently, 
the selected needle rises as the selector tooth travels upwardly along the 
contact surface of the upper cam. This upward movement of the selected 
needle causes the loop on that needle to slide downwardly past the latch 
thereby moving the latch down to the hook open position. During this 
upward movement of the selected needle, the following needle (and all 
non-selected needles) engage the lower cam which initially maintains the 
hooks of the non-selected needles below the sinkers. 
As the butt of the selected needle travels upwardly along the upper cam, 
the loop on that needle continues to slide downwardly where it encounters 
a deflector formed on the shank of the needle. The loop widens as it 
slides down the deflector. When the butt of the selected needle reaches 
the apex of the upper cam, the loop is enlarged laterally into the plane 
of the following needle. The hook at the distal end of the deflector 
catches the loop which prevents it from sliding down past the deflector. 
While the butt of the selected needle is traveling along the upper cam, the 
butt of the following needle engages the lower cam which causes the 
following needle to rise. The following needle is raised to the extent 
that the loop on that needle travels far enough down the shank of the 
needle to move the latch downwardly to the hook open position. The loop, 
however, does not move past the latch. A downwardly sloping lower contact 
surface of the upper cam then forces the following needle to move back 
down below its sinker but the latch on that needle remains down in the 
hook open position. 
Naturally, more than one loop transfer zone can be used to accelerate the 
loop transfer process and to create more complex open-work patterns in the 
fabric being formed. 
After the needles exit the loop transfer zones, they enter the loop release 
zone. In the loop release zone all of the needles are first raised to a 
height sufficient to cause the loops on the needles to slide past the 
latches and are then lowered down below the sinkers. Consequently, all of 
the needles release their respective loop. The needles then leave the loop 
release zone and again rotate past the feeder mechanism where yams are 
again placed on all of the needles and the process is repeated. 
These and further and other objects and features of the invention are 
apparent in the disclosure, which includes the above and ongoing written 
specification, with the claims and the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT AND BEST MODE 
Referring now specifically to the drawings, a segment of a knitting machine 
with needles according to the present invention is illustrated in FIGS. 
1-7, and shown generally at reference numeral 10. The knitting machine 10 
may be a modification of a lace pantyhose machine, or other knitting 
machine suitable for forming tubular knit fabrics with open-work areas. 
Such machines 10 typically have a hollow needle cylinder 12 mounted in a 
housing (not shown). The cylinder 12 is rotated by conventional means 
about its longitudinal axis during fabric formation. A plurality of axial 
slots 16 are formed in an exterior surface 18 of the needle cylinder 12, 
and a plurality of needles 30 are slidably mounted in the slots 16 for 
reciprocating up-and-down movement under the control of mechanical, 
electromechanical or electronic patterning and fabric formation devices. A 
needle 30 suitable for use with the machine 10 is shown generally in FIG. 
11 and described in connection with FIGS. 1-7. 
A plurality of resilient rings (not shown) are positioned around the 
needles 30 and the needle cylinder 12 to maintain the position of the 
needles 30 in the slots 16. Due to the rotation of the needle cylinder 12, 
the needles 30 revolve about the vertical axis of the needle cylinder 12. 
A plurality of sinkers 20 are positioned on a top end 22 of the needle 
cylinder 12. 
Each needle 30 has an elongate shank 32 having opposed ends. A hook 34 with 
a pointed loop-penetrating extension 34A is formed in a top end 36 of the 
needle shank 32, and a butt 50 is formed in the bottom end 40 of the 
needle shank 32. Below the hook 34, a latch 42, pivotally attached to the 
needle shank 32, opens and closes the hook 34. The latch 42 pivots between 
a hook closed position in which the distal end 44 of the latch 42 abuts 
the distal end 46 of the hook 34 and a hook open position in which the 
latch 42 abuts the needle shank 32 and is distally disposed with respect 
to the hook 34. The hook 34 and latch 42 are radially aligned with respect 
to the needle cylinder 12 with the open side of the needle 30 facing 
outwardly. In a loop transfer zone, an actuator selects a needle 30a in a 
conventional manner and raises the selected needle 30a to a position that 
aligns needle butt 50 with a contact surface of the a lower cam 102a. 
Consequently, the selected needle 30a rises as the butt travels upwardly 
along the contact surface of the lower cam 102a. This upward movement of 
the selected needle 30a causes the loop 60 on the selected needle 30a to 
slide downwardly past the latch 42 thereby moving the latch 42 down to the 
hook open position, as shown in FIG. 2. The lower cam 102a raises the 
selected needle to a position in which the butt 50 of the selected needle 
30a is aligned with an upper contact surface of the upper cam 102b. During 
this upward movement of the selected needle 30a, the following needle 30b 
(and all non-selected needles) engage the lower cam 102a which initially 
maintains the hooks of the non-selected needles below the sinkers 20. 
As the butt 50 of the selected needle 30a travels upwardly along the upper 
cam 102b, the loop 60 continues to slide downwardly where it encounters 
the deflector 26 carried on the shank 32 of each needle 30. The yarn 
slides down the curved surface of the deflector 26, which causes the loop 
to widen. When the butt 50 of the selected needle 30a reaches the apex of 
the upper cam 102b, the loop is enlarged sufficiently to reside with the 
plane of vertical movement of the following needle 30b. The catch 28 at 
the distal end of the deflector 26 catches the loop which prevents it from 
sliding off of the lower end of the deflector 26 and onto the lower 
portion of the needle shank 32. While the butt 50 of the selected needle 
30a is traveling along the upper surface of cam 102b, the butt 50 of the 
following needle 30b engages a first section of the upper cam 102b which 
causes the following needle 30b to rise. The following needle 30b is 
raised to the extent that the loop on that needle travels far enough down 
the shank 32 of the needle 30b to move the latch 42 downwardly to the hook 
open position. The loop, however, does not move past the latch 42. The 
upper cam 102b then forces the following needle 30b to move back down 
below its sinker 20 but the latch 42 on the needle 30b remains down in the 
hook open position. 
The cam 102a again raises the following needle 30b. Because the apex of the 
cam 102a corresponds to the apex of the cam 102b, the following needle 30b 
rises up through the enlarged loop positioned around the bottom end of the 
deflector 26 of the selected needle 30a. The hook 34 of the following 
needle 30b is positioned above the loop, but the distal end of the latch 
42 of the following needle 30b remains below the loop. The following 
needle 30b remains in this position until its butt 50 encounters the 
contact surface of cam 102c. The second cam 102b and third cam 102c are 
spaced apart to provide sufficient time for the following needle 30b to 
rise up through the enlarged loop. The cam 102c is generally shaped like a 
trapezoid inverted with respect to the cam 102a. The cam 102c has a 
downwardly sloping contact surface proximate the cams 102a and 102b. See 
FIGS. 4 and 5. 
The butt 50 of the selected needle 30a engages the downwardly sloping 
contact surface of the cam 102c causing the selected needle 30a to move 
downwardly. The loop 60 slides upwardly on the shank 32 of the selected 
needle 30a. The loop 60 forces the latch 42 to move upwardly to the hook 
closed position which prevents the loop from returning into the hook 34 of 
the selected needle 30a. When the hook of the selected needle 30a moves 
down below its sinker 20, the loop is released. The cam 102c forces the 
selected needle 30a down below the sinker 20 before it forces the 
following needle 30b to do the same. The loop 60 is caught in the hook 34 
of the following needle 30b which is still positioned above its sinker 20 
and which still has its latch 42 in the hook open position. Finally, the 
cam 1 02c forces all of the needles 30 to move down below their respective 
sinkers 20. Naturally, more than one loop transfer zone can be used to 
accelerate the loop transfer process and to create more complex 
perforation patterns in the hosiery article being formed. 
After the needles exit the loop transfer zones, they enter the loop release 
zone. In the loop release zone all of the needles 30 are first raised to a 
height sufficient to cause the loops 60 on the needles to slide past the 
latches 42 and are then lowered down below the sinkers 20. Consequently, 
all of the needles 30 release their respective loop 60. The needles then 
leave the loop release zone and again rotate past the feeder mechanism 
where loops are again placed on all of the needles and the process is 
repeated. 
An apparatus and method for producing fine gauge open-work tubular knitted 
fabrics is described above. Various details of the invention may be 
changed without departing from its scope. Furthermore, the foregoing 
description of the preferred embodiment of the invention and the best mode 
for practicing the invention are provided for the purpose of illustration 
only and not for the purpose of limitation--the invention being defined by 
the claims.