Crossing thread supply system for a weaving machine

The crossing thread supply system for the weaving machine employs a rotatable bobbin carrier and a thread tensioning means for controlling a thread pay-out from a bobbin on the carrier as a function of thread tension. The tensioning means employs a control lever which is pivotable under the influence of the paid-out thread and a pivoting lever which engages via a pawl with a ratchet wheel connected to the bobbin carrier. The control lever serves to pivot the pivoting lever when moved to an innermost position. This disengages the pawl from the ratchet wheel to permit indexing of the ratchet wheel and bobbin carrier.

This invention relates to a crossing thread supply system for a weaving 
machine. More particularly, this invention relates to a crossing thread 
supply system for a weaving machine for making fabric containing leno 
weaves. 
Heretofore, it has been known to provide weaving machines with a crossing 
thread supply system, for example as described in Swiss Pat. No. 227,334. 
In such cases, a crossing thread is drawn from a reserve bobbin over a 
thread brake for delivery to the weaving machine. The thread is then 
passed over a spindle whorl for incorporation into a shed of warp yarns 
formed by heddles of the weaving machine. However, during rotation of the 
spindle whorl or during movement of the heddles from an extreme position 
into a closed shed position, the crossed threads lose their tension more 
or less and may droop. This, in turn, may cause disturbances in the 
weaving operation. 
Accordingly, it is an object of the invention to provide a thread supply 
system in which reserve threads can be continuously supplied under 
tension. 
It is another object of the invention to provide a crossing thread supply 
system of relatively simple construction for mounting on weaving machines. 
It is another object of the invention to provide a crossing thread supply 
system for supplying threads under continuous tension to a weaving 
machine. 
Briefly, the invention provides a crossing thread system for a weaving 
machine which is comprised of at least one pair of thread reserve bobbins 
for paying out threads and a spring biased thread tensioning means for 
controlling each thread pay-out as a function of thread tension. The 
system allows the paid-off crossing thread to be supplied continuously 
under a desired thread tension. Thus, the thread can no longer droop and 
become caught on any machine part. As a result, the weaving operation of 
the weaving machine will not be disturbed. 
In one embodiment, the crossing thread supply means includes a rotatable 
bobbin carrier for receiving a reserve thread bobbin and a thread 
tensioning means for controlling the thread pay-out from the bobbin as a 
function of thread tension. In this case, it is possible to mount the 
bobbin under especially low friction so that the thread can be kept under 
low tension and be subject to relatively low stresses. 
The tensioning means includes a control lever having a thread eyelet which 
is movable under the influence of the tension in the thread passing 
through the eyelet to move from an outer position towards an inner 
position. In addition, the tensioning means includes a spring biasing the 
lever towards the outer position and means for indexing the carrier in 
response to the control lever moving into the inner position. The indexing 
means allows the carrier to move ahead incrementally to pay-out a fresh 
length of thread to the weaving machine while the control lever moves back 
to an outer position.

Referring to FIG. 1, the weaving machine is constructed in conventional 
fashion. As shown, the weaving machine includes two machine cheeks 2, 3 
across which a main shaft 5 is mounted and driven via a motor 4. A weft 
thread 6 is drawn off a stationary bobbin 8 by means of a projectile 7 and 
is inserted into a shed of warp yarns formed within the machine by means 
of a multiplicity of heedles 11. The projectile 7 is picked into the shed 
by a picking mechanism 9 on one side of the machine and received in a 
catch mechanism 10 on the opposite side of the machine. A suitable read 12 
is provided for beating up the picked weft thread and a cloth beam 14 is 
provided for winding up the resulting fabric 13. As shown, the two edges 
15 of the fabric 13 contains leno weaves, for example half twist weaves or 
twist leno weaves. These weaves are produced by two crossing thread supply 
systems 16. 
Referring to FIGS. 2 and 3, each crossing thread supply system is secured 
on a support 17 connected with the frame of the weaving machine 1. As 
indicated in FIG. 3, each supply system 16 contains a base plate 18 which 
is secured in suitable manner to the support 17. A drive shaft 21 for the 
supply system 16 is housed in the support 17 and passed through the plate 
18. This shaft 21 is driven off the weaving machine in known manner and 
continuously rotates during operation of the weaving machine 1. 
A pinion 22 is mounted on the drive shaft 21 and meshes with two gears 23 
(only one of which is shown in FIG. 3). Each gear 23 is mounted on an axle 
25 journalled in the base plate 18 and carries a disk 26 at the upper 
surface for rotation therewith. As shown in FIG. 2, an intermediate gear 
31 is also in mesh with the pinion 22 as well as with two further gears 23 
with disks 26 disposed on the right. 
Referring to FIGS. 4 and 5, each disk 26 carries a pair of rotatable bobbin 
carriers 28 for receiving thread reserve bobbins 29 (only one of which is 
shown). Each disk 26 is also coupled to a thread guide tube 33 (FIG. 5) 
through which a thread pair 45, 46 paid-out from the two associated 
bobbins 29 is guided downward and supplied, for example to a spindle whorl 
(not shown) and, thereupon, introduced into the weaving machine. As shown, 
each guide tube 33 extends through the disk 26 at a central point coaxial 
with the axle 25 (see FIG. 3). 
A thread tensioning means is also mounted on each disk 26 adjacent a 
respective carrier 28 for controlling a thread pay-out from a bobbin 29 as 
a function of thread tension. As shown in FIG. 4, each tensioning means 
includes a control lever 37 which is pivotally mounted on an axle 35 
secured to the disk 26. The control lever 37 is provided with a thread 
eyelet 36 at the free end which is disposed in the path of a thread 45, 46 
and is spring biased by a spring 55 to move from an inner position to an 
outer position opposite to the direction of thread pay-out to impart a 
tension in the thread. As shown in FIGS. 5 and 6, the spring 55 is wrapped 
about a threaded extension 61 of the axle 35 with one end anchored in an 
intermediate point of the control lever 37 and the opposite end 63 
anchored in a nut 54 threaded into the axle extension 61. A locking nut 62 
is also threaded onto the extension 61 to lock the adjusting nut 54 in in 
place. The tension of the spring 55 can be adjusted to a desired amount 
during weaving by turning of the nut 54. 
Referring to FIG. 4, each tensioning means is also provided with a means 
for indexing a carrier 28 in response to the control lever 37 moving into 
the inner position. As shown, the indexing means includes a ratchet wheel 
27 which is connected to the carrier 28 and a second pivoting lever 40. 
The ratchet wheel 27 is secured in coaxial relation with the bobbin 
carrier 28 in any suitable manner for coincident rotation. Each ratchet 
wheel 27 is mounted in freely rotatable relation on the disk 26 to rotate 
independently of the rotation of the disk 26. The pivoting lever 40 is 
mounted on the axle 35 in common with the control lever 37 and carries a 
thread guide 38 at the free end. The pivoting lever 40 also has a curved 
slot 39 at an intermediate point and a pawl 41 which engages the ratchet 
wheel 27. The slot 39 receives a bolt 42 (see FIG. 6) which is secured to 
the control lever 37 and depends into the slot 39. 
The levers 37, 40 are independently pivotable about the axle 35. However, 
the pivoting lever 40 is caused to pivot with the control level 37 when 
the control lever 37 moves into an inner position with the bolt 42 
abutting against the innermost edge of the slot 39. At this time, the pawl 
41 disengages from the ratchet wheel 27. 
Referring to FIG. 2, during operation, the four disks 26 of the supply 
system 16 are set into rotation continuously from the drive shaft 21 via 
the gears 23 according to the arrows 43 so that pairs of bobbins 29 
arranged on the same disk 26 rotate about a thread system 44 disposed at 
the upper end of a thread guide tube 33. 
Referring to FIG. 4, the crossing thread 45 paid-out from the bobbin 29a is 
shown in solid line while the thread 46 paid-out from the bobbin 29 is 
shown in broken line. The bobbins 29, 29a rotate in the direction 
indicated by the arrows 47, 48. The threads 45, 46 are drawn off in the 
direction indicated by the arrows 49, 51 and pass through the eyelet 44 
into the guide tube 33 and are drawn off downwardly as indicated by the 
arrows 53 in FIG. 5 to the weaving machine (not shown). As shown in FIG. 
4, the thread 45 passes through the eyelet 38 on the pivoting lever 40 and 
the eyelet 36 on the control lever 37 before passing to the eyelet 44. 
Likewise, the thread 46 passes through the eyelets 38, 36 of the levers 
40, 37 of the other tensioning means. 
As shown in the upper part of FIG. 4, before paying-out the thread 46, the 
control lever 37 is in an outer position so that the bolt 42 is located at 
the outer end 53 of the slot 39 of the pivoting lever 40. Upon consumption 
of warp thread or of the crossing thread in the weaving machine, the 
control lever 37 successively moves towards the inner position against the 
bias of the spring 55. The thread loop 56 thus becomes shorter and the 
bolt 42 finally reaches the other end 57 of the slot 39 (i.e. the position 
shown for the lower control lever 37a). 
Upon a further inward pivoting of the control lever 37, the pivoting lever 
40 is taken along via the bolt 42. Both levers 37, 40 are then pivoted 
about the axle 35 in a clockwise manner, as viewed, so that the pawl 41 
disengages from the ratchet 27 to actuate the play-out of the thread 45. 
The ratchet wheel 27 then advances by one step in the direction indicated 
by the arrow 47, i.e. clockwise, under the action of the slight tension in 
the thread 45. As the tensile stress in the thread 45 then decreases, the 
control lever 37 is pivoted counter clockwise by the spring 55 as viewed 
in FIG. 4 with the pivoting lever 40 following in the same direction of 
rotation. As indicated, the control lever 37 is pivoted to the outer 
position by the spring 55 so that the bolt 42 strikes the outer end of the 
slot 39 such that the pivoting lever 40 moves counterclockwise as viewed. 
The pawl 41 is thus engaged with the next following tooth 57 of the 
ratchet wheel 27. The ratchet wheel 27 and the associated bobbin 29 are 
again secured against relative rotation and the process at the levers 37, 
40 repeats. 
The crossing thread supply means can be used, for example as a complete 
crossing (leno) system. To this end, a spindle whorl would be connected 
after the guide tube 33. Alternatively, the supply system may be used in 
connection with a half-twist device. For this purpose, the thread guide 
tube 33 would be followed, for example by a leno-edging suspended in the 
heddles 11 of the weaving frame 1. In this case, the drive shaft 21 and 
gears 23 of the disk 26 would be eliminated, for example as indicated in 
FIG. 7 wherein like reference characters indicate like parts as above. In 
this case, the system contains pairs of disks 26 with associated bobbin 
parts 29, 29a mounted on a base plate 18. 
In the various embodiments, the levers 37, 40, pawl 41 and ratchet wheel 27 
serve as a control for the paying-out or pulling off of the crossing 
threads 45, 46 from the bobbins 29 as a function of the tension of these 
threads. 
It is to be noted that the pivoting movement of the control lever 37 which 
occurs under spring action allows the differences of length of the 
crossing threads 45, 46 which result during the rotation of a following 
spindle whorl, or during an up and down movement of the heddles, to be 
absorbed and the crossing threads maintained continuously under 
approximately equal tensile stress.