[0001] The present invention relates to a device for forming chenilles on a crochet textile
machine for warp weaving, said textile machine being of the type comprising a plurality
of needles set side by side, at least one front bar presenting recesses for guiding
said needles, a plurality of thread passers positioned side by side parallel to the
front bar forward of the needles and set to engage each a respective warp thread,
a plurality of thread-guiding cops positioned above the needles and able to engage
each a respective woof thread and means for driving the needles longitudinally to
confer thereto an alternating motion along their longitudinal development.
[0002] As is well known, in crochet textile machines for warp weaving the formation of the
manufactured item is effected in correspondence with a front bar where a plurality
of needles set side by side and simultaneously driven in the sense of their longitudinal
development operates.
[0003] In front of the needles operates a plurality of thread passers through which the
warp threads pass.
[0004] The co-operation between needles and thread passers gives rise to a sequence of woven
stitches which form a plurality of parallel chains, as many as there are warp threads,
which descend progressively from the front bar. The chains are normally concatenated
with woof threads borne by respective thread-guiding cops operating above the needles.
[0005] Each woof thread is selectively laid astride one or more needles and passes underneath
them when they reach the return stop.
[0006] The woof thread placed below the needles is enmeshed in the woven stitches of the
warp threads in the following operative cycle.
[0007] If fabrics provided with chenilles are to be produced, to obtain such chenilles it
is necessary, as is well known, to cut the woof threads.
[0008] The prior art for the formation of chenilles in crochet textile machines consists
of placing a series of scissors cutting elements where space is available for their
operative installation, i.e. below the front bar. Such scissors cutting elements,
with double blade, require appropriate control means that allow to actuate the closure
and opening of one blade with respect to the other.
[0009] The prior art, summarily described above, presents important drawbacks.
[0010] First of all, the chenilles that are obtained from the cutting action of the scissors
elements, i.e. the sections of cut woof threads, are rather irregular with non uniform
length since, due to the considerable distance between the area where the stitches
are formed, i.e. the area of the needles, and the area where the woof threads are
cut, the fabric is never set at each cut exactly in the same position or with the
same alignment as the previous cut.
[0011] Moreover, prior art scissors cutting devices require their own control means and
present rather considerable constructive complexity.
[0012] Their mounting and setting-up operations are also generally not simple and need non
negligible operating times.
[0013] In this situation, the technical task constituting the basis for the present invention
is to conceive a device for the formation of chenilles for crochet textile machines
for warp weaving able substantially to obviate the aforementioned drawbacks.
[0014] Within said technical task, an important aim of the invention is to conceive a device
that allows to attain a high precision in the execution of the cut of the woof threads
and thereby to obtain regular and uniform chenilles.
[0015] Another important aim of the invention is to conceive a simple device of reliable
operation.
[0016] A further aim is to obtain a device that allows to set up rapidly with simple operations
a crochet textile machine when the production of chenille fabrics is required.
[0017] The technical task and the aims specified are essentially attained by a device for
the formation of chenilles on a crochet textile machine for warp weaving which is
characterised in that it comprises a plurality of cutting elements able to cut woof
threads and positioned immediately below the area occupied by the needles wherein
the woven stitches are formed and means for controlling said cutting elements.
[0018] The description is now provided, purely by way of indicative and non limiting example,
of a preferred but not exclusive embodiment of a device according to the invention
illustrated in the accompanying drawings, wherein:
- Figure 1 shows an interrupted perspective view, partially sectioned, of a portion
of crochet machine provided with a device according to the present invention;
- Figure 2 shows a view analogous to Figure 1 but in a different operative phase;
- Figure 3 highlights a section of the machine in Figure 1 according to a vertical plane
transverse to the front bar; and
- Figure 4 presents an enlarged front view of the front bar and of the manufactured
item.
[0019] With reference to the mentioned figures, the device according to the invention is
globally indicated with the number 1.
[0020] It is applied to a crochet textile machine known in the art comprising a plurality
of needles 2 set side by side parallel to each other and slidingly guided by recesses
3 obtained in a front bar 4.
[0021] Forward of the needles 2 and positioned side by side and parallel to the front bar
4 is a plurality of thread passers 5 set to engage each a respective warp thread 6.
[0022] Above the needles 2 operate, consecutively set side by side parallel to the front
bar 4, thread-guiding cops 7 able to carry woof threads 8 to be concatenated with
chains 9 formed by woven stitches 9a obtained from the warp threads 6 and all together
defining a manufactured item 10. Longitudinal drive means 11 impose on needles 2 a
simultaneous alternating motion along the direction of their longitudinal development.
[0023] Originally, the device 1 for the formation of chenilles comprises a plurality of
cutting elements 12 able to cut the woof threads 8 of the manufactured item 10 immediately
below the area occupied by the needles 2, i.e. the area wherein the stitches 9a are
formed.
[0024] More specifically, cutting elements 12 advantageously operate on the manufactured
item 10 in an area essentially comprised between a common base plane of the needles
10 and a lower edge 4a of the front bar 4.
[0025] The cutting elements 12 are defined by a plurality of blades slidingly housed in
guiding grooves 13 obtained in the front bar 4 and intercalated between the guiding
recesses 3 of the needles 2.
[0026] In practice the blades 12 present a longitudinal development parallel to that of
the needles and, similarly thereto, comprise L-shaped rear attachment ends 12a able
to be rigidly engaged to control means which, in a preferential embodiment, coincide
with the means 11 for longitudinally driving the needles.
[0027] Such means 11 for longitudinally driving the needles 2 and the blades 12 comprise
a movable front bar 14, actuated by appropriate kinematic mechanisms in a way known
in itself, which confers simultaneously the same alternating motion to the needles
and to the blades themselves.
[0028] The blades 12, to the side opposite to the attachment ends 12a, present each a front
cutting portion 12b provided with a chamfered cutting edge 12c, oriented upwards,
and with a pointed termination.
[0029] Advantageously the recesses 13 guiding the blades 12 present a depth suited to set
the cutting edges 12c of the blades 12 at an appropriate distance from the needles
2, essentially corresponding to two woven stitches (see figure 4) and in any case
preferably not exceeding five woven stitches.
[0030] The operation of the subject device, described above in a mainly structural sense,
is as follows.
[0031] At each advancing motion of the needles towards the thread passers 5, the blades
12 also move from a back position wherein they do not emerge from the front bar 4
(see Figure 1) to positions progressively emerging more and more therefrom (see Figure
2).
[0032] The woof threads 8 already enmeshed in the woven stitches 9a and interfering with
the cutting edges 12c of the blades 12 are cut by such advancing motion of the blades
themselves and form the chenilles 10a (see Figure 4).
[0033] Since each cutting action is performed in an area at a very short distance from the
needles 2, the positioning of the woven chains 9 in such area of intervention is repeated
always with the same precision and therefore the chenilles obtained present a high
degree of regularity.
[0034] The invention attains important advantages.
[0035] First of all, with respect to the prior art, a greater number of cutting elements
can be available, since each blade can be located without any problems between each
pair of adjacent needles.
[0036] This also makes it possible to work with values of refinement superior to those attainable
in the prior art.
[0037] The efficiency of the device in the formation of chenilles is therefore improved.
[0038] Moreover, the device is simpler and more reliable overall than the devices with scissors
cutting elements, as it requires no additional driving means.
[0039] Lastly, also the setting-up process of a textile machine for producing chenille fabrics
becomes easier and quicker since it is possible to have in stock a movable front bar
wherein both the needles and the blades are already mounted and engaged, to be easily
replaced with the movable front bar fitted only with needles, thereby avoiding the
complex operations of mounting and demounting the scissors cutting elements of the
prior art.
1. Device for forming chenilles on a crochet textile machine for warp weaving, said textile
machine comprising:
a plurality of needles (2) set side by side,
at least one front bar (4) presenting recesses (3) for guiding said needles (2),
a plurality of thread passers (5) positioned side by side parallel to the front bar
(4) forward of the needles (2) and set to engage each a respective warp thread (6),
a plurality of thread-guiding cops (7) positioned above the needles (2) and able to
engage each a respective woof thread,
and means (11) for longitudinally driving the needles to confer thereto an alternating
motion along their longitudinal development,
characterised in that it comprises a plurality of cutting elements (12) able to cut
woof threads (8) and positioned immediately below the area occupied by the needles
(2) wherein the woven stitches (9a) are formed, and means for controlling said cutting
elements.
2. Device according to claim 1, characterised in that said cutting elements (12) operate
on the woof threads (8) in an area essentially comprised between a base plane of the
needles (2) and a lower edge (4a) of the front bar (4).
3. Device according to claim 1, characterised in that said cutting elements (12) are
defined by a plurality of blades interposed between said needles (2) and in that said
front bar (4) presents grooves (13) for guiding said blades (12) intercalated between
said recesses (3).
4. Device according to claim 3, characterised in that said blades (12) present a longitudinal
development parallel to the needles (2) and said means for controlling the blades
are defined by said means (11) for longitudinally driving the needles and simultaneously
confer an alternating motion to the needles (2) and to the blades (12).
5. Device according to claim 4, characterised in that said means (11) for longitudinally
driving the needles and the blades comprise at least one movable front bar (14) rigidly
engaging rear attachment ends (12a) of the blades and of the needles.
6. Device according to claim 3, characterised in that each of said blades (12) presents
a front cutting portion (12b) provided with a cutting edge (12c) that is chamfered
and oriented upwards.
7. Device according to claim 6, characterised in that said grooves (13) for guiding the
blades present a depth suited to position said cutting edges (12c) of the blades (12)
at a distance from the needles (2) not exceeding five woven stitches (9a).