A loom includes a plurality of reciprocatably displaceable heald devices each generally disposed in a respective one of a plurality of parallel planes, and a plurality of levers each coupled through an intermediate element to a respective one of the heald devices. The respective pivot axis of each of at least two levers is differently spaced from the respective intermediate element to cause a respectively different displacement stroke for each of the at least two heald devices connected thereto. The respective pivot axis of each of the at least two levers is differently spaced from a plane which extends centrally of each heald device, parallel to the line of displacement thereof and perpendicularly to the planes of the heald devices.

BACKGROUND OF THE INVENTION 
The present invention relates to a loom. 
Looms comprising heald devices of shafts are known, in which for the 
movement of the heald devices, levers are used. The levers have pivot axes 
which are aligned with one another and extend at right angles to the 
planes spanned by the heald devices. When a greater number of heald 
devices is present in such looms for the weaving of patterned fabric, 
different heald devices are frequently displaced different distances from 
their rest positions in the formation of the sheds in order to attain a 
favorable deflection of the warp threads. In order to produce these 
different displacements, the levers operatively connected with the heald 
devices have different lengths. The levers have drive output points, where 
the levers are connected with the heald devices, which are in most of the 
levers inevitably removed relatively far from the plane of symmetry of the 
center plane which extends through the centre points of the heald devices 
parallel to the direction of motion of the heald devices and at right 
angles to the planes spanned by the heald devices. In a known type of 
loom, the levers at the drive output points engage parts which are rigidly 
fastened to the heald devices. In operation, turning moments arise in 
respect of the center points of the heald devices. These turning moments 
must be absorbed by heald device guides and therefore cause noise, 
increase the wear and limit the maximum possible weaving speed. 
In another loom, the levers are connected with the heald devices through 
flexible tension ropes. Although it is possible in that case to deflect 
the tension ropes by means of rollers and to fasten the tension ropes to 
the heald devices in the plane of symmetry or central plane, the 
additionally necessary deflecting rollers cause the manufacturing costs to 
be increased. Moreover, tension ropes deflected over rollers tend to 
deflect out laterally at great speeds, whereby the maximum weaving speed 
is limited. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide a loom in which the heald 
shafts are displaceable by different distances without the aforementioned 
disadvantages occurring. 
According to the present invention there is provided a plurality of heald 
devices each reciprocatably displaceable along respective paths and each 
generally disposed in a respective one of a plurality of parallel planes. 
The plurality of heald devices are disposed so that a common plane extends 
centrally of each of the plurality of heald devices, parallel to the paths 
and perpendicular to each of the parallel planes. Each of a plurality of 
levers is pivotable about a pivot axis to cause the displacement of a 
respective one of the plurality of heald devices. Each of a plurality of 
intermediate elements is connected between a respective one of the heald 
devices and a respective one of the levers. The pivot axis of at least two 
levers is differently spaced from the respective intermediate element to 
provide a different displacement stroke for each which corresponds to at 
least two heald devices and the pivot axis of each of said levers is 
differently spaced from said common plane. 
Thus, it is an object of the invention to provide a loom having a plurality 
of heald devices, each of the heald devices being generally disposed in a 
respective one of a plurality of parallel planes, and each of the heald 
devices being reciprocatably displaceable along a respective path in its 
respective one of the parallel planes. The plurality of heald devices is 
so disposed that a common plane extends centrally of each of the plurality 
of heald devices. The common plane is disposed parallel to the paths and 
perpendicular to each of the parallel planes. The loom includes a 
plurality of levers each pivotable about a pivot axis to cause the 
reciprocatory displacement of a respective one of the plurality of heald 
devices. The loom further includes a plurality of intermediate elements 
each connected between a respective one of the heald devices and a 
respective one of the levers. The pivot axis of each of at least two of 
the levers is differently spaced from the respective intermediate element 
connected thereto so as to provide a respectively different displacement 
for each heald device connected thereto. The pivot axis of each of the at 
least two said levers is differently spaced from the common plane. 
It is a further object of the invention to provide a loom which is simple 
in design, rugged in construction and economical to manufacture. 
For an understanding of the principles of the invention, reference is made 
to the following description of typical embodiments thereof as illustrated 
in the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIGS. 1 and 2 show parts of a tape loom including the shed-forming device 
thereof. The shed-forming device comprises several heald devices or heald 
shafts are arranged behind one another in the longitudinal direction of 
the warp threads and of which five are shown in FIG. 1 and designated by 
1, 2, 3, 4 and 5. The heald device 1 is disposed foremost, i.e. nearest to 
a reed 11 which is pivotably mounted in a bearing 13 of the machine frame. 
The remaining heald devices then follow one another sequentially so that 
the heald device 5 is furthest from the reed 11. Each device comprises a 
frame 1a, 2a, 3a, 4a and 5a and vertically, extending healds 1b, 2b, 3b, 
4b and 5b and with thread guide eyelets 1c, 2c, 3c, 4c and 5c. 
The warp threads are, prior to their entry into the shed-forming device, 
guided by means of a thread guide 15 so that they lie in, plane. The warp 
threads then extend through the shed-forming device. In operation, a weft 
thread loop is introduced into the just formed shed 20 by means of a 
weft-introducing needle 17 during each shed change. The fabric arising at 
the reed abutment point 19 is then guided and spooled by means of rollers 
(not shown). 
In the shed-forming device, each warp thread is guided through one of the 
thread guide eyelets 1c, 2c, 3c, 4c and 5c. In the formation of a shed 20 
the warp threads are deflected in layers by the heald devices, for which 
the heald device 1 holds the warp thread layer 21, the head device 2 the 
layer 22, the heald device 3 the layer 23, the heald device 4 the layer 24 
and the heald device 5 the layer 25. In the illustrated position of the 
heald devices, the warp thread layers 22 and 24 form the lower boundary of 
the shed 20. In the region of the shed 20, i.e. between the foremost heald 
devices 1 and the abutment point 19 of the reed 11, the lower warp thread 
layers 22 and 24 lie at least approximately in the same plane. 
Correspondingly, also the upper warp thread layers 21, 23 and 25 lie at 
least approximately in the same plane in the region of the shed 20. This 
deflection of the warp threads is attained thereby due to different 
displacements of different heald devices. 
Vertical rods 31 are fastened to the upper frame limbs of the heald devices 
1, 2, 3, 4 and 5. These are guided to be vertically displaceable above the 
warp threads in schematically illustrated guides 33 fastened to the frame 
of the loom. Furthermore, only schematically illustrated tension springs 
35 are shown, which at one end are fastened to the frame part 37 and at 
the other end engage at the rods 31 and pull the heald devices upwardly. 
A heald device driving means comprises a shaft 53, which is rotatably 
journalled by means of bearings 51 in the frame of the loom and which 
extends at right angles to the planes containing the heald devices. A cam 
disc 55, for each heald device, is fastened rotationally fast on shaft 53. 
Cams 57 can be mounted on cam disc 55 at points uniformly distributed 
around the disc circumference. The cams can, for example, be mounted at 
circumferential points which are spaced from one another by 60.degree. or 
a multiple thereof. For the remainder, the cam discs and cams are all 
identically constructed apart from the fact that the different cam discs 
can be equipped with differently arranged and different number of cams. In 
particular, all cam discs have the same diameter and all cams the same 
height. 
The heald device driving means furthermore comprises a lever for each heald 
device. The levers associated with the devices 1, 2, 3, 4 and 5 are shown 
in FIG. 3 and designated by 61, 62, 63, 64 and 65. The levers are 
pivotably mounted by pins, the pivot axes of which are designated by 71, 
72, 73, 74 and 75, in bearings 81, 82, 83, 84 and 85 fastened on the frame 
of the loom. Mounted at one end of each lever is a feeler roller 59, which 
bears against the circumferential surface of the cam disc 55 associated 
with the lever concerned and tracks the surface. 
Guide rods 41, 42, 43, 44 and 45 are each united by means of a hinge pin 47 
to a respective lever 61, 62, 63, 64 and 65 at the end of the lever remote 
from the feeler roller 59. The other end of each of the guide rods are 
united, by means of hinge pins 49 with straps which are rigidly fastened 
to the lower frame limbs of the heald devices. As is evident from FIG. 2, 
the pivot axes of the hinge pins 47 and 49 connecting the guide rods with 
the levers and heald device, respectively, extend at right angles to the 
planes containing the heald devices. Furthermore, the pivot axes of the 
hinge pins 49 lie in the plane extending parallel to the direction of 
displacement of the heald device, i.e. vertically, which forms a central 
plane 90 common to all heald devices 1, 2, 3, 4 and 5 as well as a plane 
of symmetry of the shaft frames. In one or two of the lever positions 
resulting during the following of the cam discs 55, the guide rods 41, 42, 
43, 44 and 45 extend exactly vertically so that then the pivot axes of the 
hinge pins 47 lie in the central plane 90. In the remaining lever 
positions occuring in operation, the pivot axes of the hinge pins 47 are 
slightly displaced from the central plane 90. During the raising and 
lowering of the heald devices, the hinge pins, which form the drive output 
points of the levers, thus move along circular arcs which have a tangent 
as well as chords which run parallel to the central plane 90. Lever arms 
61a, 62a, 63a, 64a and 65a, to which the feeler rollers 59 are journalled, 
are inclined with respect to the lever arms 61b, 62b, 63b, 64b and 65b 
which are connected with the guide rods 41, 42, 43, 44 and 45. The levers 
are arranged in such a manner that the lever arms 61b, 62b, 63b, 64b and 
65b extend horizontally in the case of the mean pivot positions of the 
levers occurring in operation, i.e. at right angles to the direction of 
displacement of the heald devices. 
The pivot axes 71, 72, 73, 74 and 75 of the different levers 61, 62, 63, 64 
and 65 are disposed at different distances from the common central plane 
90 of the heald devices. The feeler rollers 59 of all levers at 
corresponding lever positions all have approximately the same position 
with respect to the cam discs. When the feeler rollers 59 have been 
deflected to approximately half the height of the cams 57, their 
geometrical axes all lie approximately in one radial plane 93, through 
which the geometric axis of the shaft 53 extends. The pivot axes 71, 72, 
73, 74 and 75 all lie in one plane 95, which extends parallel to the 
geometric axis of the shaft 53 as well as at right angles to the radial 
plane 93. At half the deflection of the feeler rollers 59 into half the 
height of the cam, the axes of the feeler rollers lie at least 
approximately in the plane 95. The latter thus extends parallel to a 
tangential plane which touches the cam disc 55 at the radial plane 93. The 
different levers have different transmission ratios, i.e. they produce 
different strokes of the heald devices at equal deflections of their 
feeler rollers 59 forming lever drive points. When, for example, the 
levers 61 and 65 have been pivoted by identically constructed cams 
engaging at their feeler roller, the feeler rollers, of both levers are 
deflected an equal distance measured radially of the shaft 53. Since the 
lever arm 65a on the drive side of the lever 65 is shorter than the lever 
arm 61a on the drive side, the lever 65 is pivoted through a larger angle 
than the lever 61. Furthermore, the lever arm 65b on the output side is 
longer than the lever arm 61b on the output side. Therefore, the hinge pin 
47 forming the drive output point of the drive output lever arm 65b is 
displaced in vertical direction through a greater travel than the hinge 
pin 47 forming the drive output point of the drive output lever arm 61b. 
The positions of the pin axes 71, 72, 73, 74 and 75 are now chosen in such 
a manner that the heald device strokes become so great that the warp 
thread layers 22 and 24 as well as also the warp thread layers 21, 23 and 
25 in the region of the shed each lie in a common plane and that the axes 
of the hinge pins 47 each according to the instantaneous lever position 
lie more or less exactly in the central plane 90. 
In operation of the tape loom, the shaft 53 with the cam discs 55 is 
rotated. Thereby, the heald devices are drawn downwardly against the force 
of the spring 35 each time the cam 57 of an associated cam disc pivots an 
associated lever. During a complete revolution of the cam discs, six shed 
changes and weft insertions take place. Different patterns can thus be 
produced by appropriate arrangement of the cams on the cam discs. 
Since the geometric axes of the hings pins 49 lie in the central plane 90 
and this is more or less exactly the case for the hinge pins 47 according 
to the instantaneous lever position, the levers 61, 62, 63, 64 and 65 or 
the guide rods 41, 42, 43, 44 and 45, respectively, exert substantially 
only vertically directed forces, which engage in the central plane 90, on 
the heald devices. The latter and their guides 33 therefore do not have to 
absorb turning or tilting moments. Therefore, great weaving speeds are 
possible. For example, 3000 or more shed changes and weft insertions per 
minute can readily take place. 
Five heald devices are shown in FIG. 1. For the production of complicated 
patterns, however, more heald devices, for example twenty, can be 
provided. In that case, each of these heald devices is connected with a 
separate lever which follows a cam disc. In this case the pivot axis of 
each lever could also be displaced from that of the adjacent lever. Since 
in the case of a great number of heald devices they are arranged closely 
beside one another, for reasons of spacing, it is difficult in some 
circumstances for all levers to have pivot bearings displaced from one 
another. 
With a great number of heald devices, one can however, construct some 
adjoining levers identically and journal them on a common hinge pin. For 
example, between the levers 61 and 62 it is possible to arrange four 
additional levers which are similar to the lever 61 and also pivotable 
around the same pivot axis 71. If in an analogous manner four additional 
levers are arranged beside each of the remaining levers 62, 63, 64 and 65, 
twenty levers altogether are then present, by which twenty heald devices 
can be raised and lowered. 
The mutually adjacent, identical levers, pivotable about a common pivot 
axis, also provide equal transmission ratios and heald device strokes. 
Since the heald devices belonging to one group of identical levers are 
disposed closely beside one another, only relatively small deviations from 
the ideal position aimed at, in which all lower and all other warp threads 
each lie in a common plane, nevertheless arise during the deflection of 
the different warp thread layers in the region of the shed 20. In so far 
as the forces exerted on the heald devices are concerned, no turning 
moments are exerted on the shafts even if a few adjacent levers are 
pivotable around a common pivot axis, because all levers are connected 
with a guide rod approximately at the central plane 90. 
When the heald devices are arranged closedly beside one another, the heald 
device driving means can be constructed as shown in FIG. 4. A shaft 153 is 
journalled in the machine frame and carries a cam disc 155 fixedly 
fastened to the shaft to rotate therewith and provided with cams 157. 
Two groups of levers are present. The one lever group, of which only the 
lever 161 is shown, is disposed above the shaft 153 and the cam discs. The 
other lever group, to which the lever 162 belongs, is disposed below the 
shaft 153 and the cam discs. Feeler rollers 159, which track the 
associated cam discs, are journalled on the lever arms 161a and 162a of 
levers 161 and 162, respectively. The lever arm 161b and 162b are 
connected through a guide rod 141 and 142, respectively, with a heald 
device (not shown). The geometric axes of hinge pins 147, which connect 
the levers and guide rods with one another, again in accordance with the 
instantaneous lever position lie at least approximately in the vertical 
central plane 190 of the heald devices. The levers 161 and 162 are 
journalled by means of bearings 181 and 182 in the machine frame, while 
the pivot axes 171 and 172, about which the levers are pivotable, have 
different spacings from the central plane 190. 
In the heald devices driving means illustrated in FIG. 4, levers or lever 
groups, which are connected with successive heald shafts or heald device 
groups, can be arranged alternately above and below the shaft 153. The 
pivot axes of the upper levers or lever groups as well as also the pivot 
axes of the lower levers or lever groups are displaced from one another. 
In this manner, the spacings between the levers or lever groups can be 
enlarged so that more space is at disposal for the journalling of the 
levers and the hinge connections between the levers and guide rods. 
The heald device driving means shown in FIG. 5 comprises a shaft 253, 
journalled in the frame and carrying cam discs 255 provided with cams 257. 
Several levers are present, of which two are illustrated and designated by 
reference numerals 261 and 265. The levers each have a respective feeler 
roller 259 following a cam disc 255. Each lever 261 and 265 is journalled 
in a bearing 281 and 285, respectively, while the pivot axes 271 and 275 
of the levers are disposed at different spacings from the central plane 
290 of the heald devices. The levers 261 and 265 are one-armed, i.e. the 
guide rods connecting them with the heald device, of which the guide rod 
241 is visible, are connected by means of hinge pins 247 on the same side 
of the pivot axes 271 and 275, on which the feeler rollers are also 
disposed. The axes of the hinge pins 247 again lie at least approximately 
on the central plane 290. 
The heald device driving means shown in FIG. 6 comprises two shafts 353 
journalled in the machine frame and extending parallelly beside one 
another in a horizontal direction. Several cam discs 355 provided with 
cams 357 are fastened to each of these shafts. Both the shafts 353 are 
arranged in mirror image symmetry on different sides of the central plane 
390 of the heald device. Serving to follow the cam discs are levers, that 
include feeler rollers 359, two of which are illustrated in FIG. 6 and 
designated by 361 and 362. The levers 361 and 362 are journalled by means 
of bearings 381 and 382, respectively, on the frame of the loom. 
Illustrated in FIG. 7 in addition to the levers 361 and 362 are two other 
levers 363 and 364 as well as the shafts 353 of the cam discs, the cam 
discs themselves being omitted for simplicity. The pivot axes, about which 
the levers are pivotable, are designated by 371, 372, 373 and 374. The 
spacings of the pivot axes 371, 372, 373 and 374 from the central plane 
390 increase in the sequence of the reference numbers, while successive 
levers are arranged alternately on different sides of the central plane. 
Coreespondingly, also the cam disc followed by the feeler rollers 359 of 
successive levers are likewise arranged alternately on the two shafts 353. 
Connected to the levers by means of hinge pins 347 are guide rods, of 
which the guide rod 341 is shown in FIG. 6. The axes of the hinge pins 347 
again according to the instantaneous lever position lie more or less 
exactly in the vertical central plane 390, along which the heald devices 
are displaced. 
Some adjacent levers can be identical and be pivotable about a common axis 
in groups in the case of the heald device driving means shown in FIGS. 6 
and 7. Since the levers are distributed over two different sides of the 
central plane 390, they can be employed for the displacement of heald 
devices disposed relatively closely on one another. 
Three levers 461, 462 and 463 each with a respective feeler roller 459 are 
shown in FIG. 8. The levers are pivotable about pivot axes 471, 472 and 
473. The pivot axes 471, 472 and 473 are disposed at different spacings 
from the central plane 490 of the heald devices. The feeler rollers all 
have approximately the same spacing from the central plane so that they 
can follow cam discs which all sit on the same shaft. Approximately 
vertically extending guide rods 441, 442 and 443 are connected by means of 
hinge pins (not shown) to the ends of te levers remote from the feeler 
rollers. The axes 446 and 448 of the joints connecting the guide rods with 
the levers do not lie in the central plane 490, but are displaced with 
respect to this on different sides. Due to the axes 446 and 448 being 
displaced from each other, more space is available for the hinge 
connections. The spacings of the axes 446 and 448 from the central plane 
490 are however, small by comparison with the heald device width measured 
in the same direction and amount at most to 10% of the heald device width. 
Only relatively small turning moments are therefore exerted on the heald 
devices in the arrangement shown in FIG. 8. 
In the heald device driving means described with reference to the drawings, 
the pivot axes of the different levers of the lever groups are thus 
displaced from one another transversely to the axial direction and have 
different spacings from the central plane, which is common to all heald 
devices and runs parallel to the direct on of displacement of the heald 
devices. During the following of several cam discs, which are arranged on 
the same or at most on two different devices and are identical apart from 
the different cams, it thereby becomes possible to attain different 
transmission ratios of the levers and thereby different heald device 
strokes and nevertheless to arrange the drive output points of all levers, 
at which the latter transmit their motion to the heald devices, at least 
approximately in the central plane. The levers can in that case be 
arranged in such a manner that their drive output arms extend 
approximately at right angles to the named central plane. During the 
pivoting of the levers, their drive output points describe a circular arc 
which displays a tangent, and preferably also chords, which extend 
parallel to the direction of displacement of the heald devices as well as 
the central plane. It thereby becomes possible to transmit the movement of 
the levers to a point, lying in the named central plane, of the heald 
devices without turning moments worthy of mention being exerted on the 
heald devices. 
The looms can be modified in different aspects. The number of heald devices 
can be varied within wide limits in accordance with the desired patterning 
of the woven fabric. In order that a pattern can be produced at all, 
several heald devices, i.e. at least three, are of course required. Since 
a lever is present for each heald device, the number of the levers is of 
course also to be determined in accordance with the patterns. 
The cam pitch divisions can also be varied in the case of the cam discs. At 
most two, four, six or more cams can be arranged on each cam disc. 
Furthermore, the levers can be pivoted, instead of by cam discs, by 
contoured discs or other drive elements, for example, cam chains or 
punched cards. In all these cases, it is possible to use driving means of 
like kind for all levers on the driving side, thus for example cam discs 
or cam chains, which all have identically constructed cams and 
correspondingly impart approximately equal strokes to all levers. 
Furthermore, also the connections between the levers and heald devices can 
be modified in a different manner. For example, in place of the described 
guide rods, one could also provide rods rigidly fastened to the heald 
devices. The lower ends of these rods could then for example be provided 
with a pin which engages into a slot extending in the longitudinal 
direction of the drive output lever arm and present in the latter. In this 
case, the cam discs and bearings of the levers can be fastened to a 
support which is displaceable transversely to the common central plane of 
the heald shafts and to the direction of the displacement of the heald 
devices. Through displacement of the support, the size of the shed, i.e. 
the opening or angle between the upper and lower warp threads at the reed 
abutment location 19 could be varied. Another possibility is to provide 
flexible tension ropes in place of the guide rods. 
While specific embodiments of the invention have been shown and described 
in detail to illustrate the application of the principles of the 
invention, it will be understood that the invention may be embodied 
otherwise without departing from such principles.