The invention relates to a weaving device comprising means
for forming a shed of warp yarns, as well as a lay, wherein a launching device is
disposed on one side of the shed for inserting a carrier which envelopes a weft
yarn in the form of a packed clew of yarn, which clew of yarn unwinds from the carrier
into an elongated weft yarn upon insertion of the carrier into the shed, and wherein
guide means are provided, which guide the carrier during its passage through the
Weaving devices of the kind referred to in the introduction
are generally known and described in
Dutch patent application No. 73/09850
, for example. With weaving devices of this type, a weft yarn from a supply
bobbin is connected to a projectile, also called shuttle, which projectile is launched
by the launching means disposed on either side of the shed, using a medium under
pressure, for example compressed air, and carried through the shed via guides disposed
in the shed.
Dutch patent application No. 1023943
in the name of the present applicant, the carrier is made of a lightweight
material, whose dimensions are barely larger than those of the clew of yarn to be
transported through the shed.
Because of the erratic nature of the carrier during its
passage through the shed,
uses a guide, which envelopes the carrier during its passage through the
shed. Such a weaving machine has drawbacks from a weaving point of view, however:
the carrier is constantly in contact with the guide, which, in addition to extra
wear, results in a loss of energy and thus a loss of velocity. To prevent extra
wear and a loss of velocity of the carrier with the yarn and the guide, the guide
must be practically stationary during insertion, which leads to high mechanical
loads on the weaving machine during high-speed operation.
The object of the invention is to provide a weaving device
of the above-described kind, which enables weaving with a carrier which is made
of a lightweight material and which has dimensions barely larger than those of the
clew of yarn to be inserted into the shed, and which does not have the complex construction
of the prior art but which enables higher weaving speeds whilst avoiding weaving
According to the invention, the guide means comprise guide
elements which are provided with a recess having an opening larger than the carrier,
such that the carrier is movable with respect to the guide during operation in a
direction transversely to the insertion direction, and wherein the guide means further
comprise blowers, which blowers are at least partially arranged for blowing air
jets in the direction of the recess of the guide elements for the purpose of keeping
the carrier in the recess during its passage through the shed.
Thus, the carrier is prevented from undesirably moving
out of the recess as a result of the erratic flight behaviour of the lightweight
carrier during its passage through the shed.
In a first embodiment, the guide elements are movable along
with the lay in a direction transversely to the direction of movement of the carrier
through the shed upon insertion of the carrier. This enables a further increase
of the weaving speed, whilst the occurrence of weaving flaws is reduced.
In various embodiments, at least some of the blowers are
oriented at an angle to the guide elements, seen in the direction of movement of
the carrier through the shed, or transversely to the guide elements or parallel
to the guide elements. With these embodiments an effective guidance of the carrier
moving through the shed at a high velocity (with the weft yarn formed into a clew
of yarn) is realised, wherein, in addition to an additional propulsion of the carrier
through the guide elements (by the blowers with the oblique or parallel orientation),
a retainment of the moving carrier in the guide elements is effected (by the blowers
with the transverse orientation), thereby preventing undesirable movement of the
carrier out of the guide elements (and thus a malfunction in the weaving process).
In one embodiment, the guide elements comprise several
lamella-like elements arranged between successive warp yarns, which are each provided
with a recess, such that the recesses of lamellae disposed adjacent to each other
form an open guide channel, through which the carrier can move freely.
In yet another embodiment, the guide elements at least
partially form part of the reed of the weaving device.
In yet another embodiment, the outlet opening of the launching
device and the guide elements are not aligned near the insertion side of the shed
at the moment when the carrier exits the outlet opening during operation. In this
way, too, a faster operation of the weaving devices is realised.
The launching device may in that case be disposed in such
a manner that the insertion direction extends at an angle to the guide elements.
The invention will now be explained in more detail with
reference to a drawing, in which:
- Figure 1 shows a first embodiment of a weaving device according to the invention;
- Figure 2 is a detail view of figure 1;
- Figures 3a-3c are plan views of figure 1;
- Figures 4a-4c are perspective views of figure 1;
- Figure 5 is another detail view of figure 1; and
- Figures 6a-6c show other embodiments of a detail view of figure 1.
For a better understanding of the invention, like parts
are indicated by the same numerals in the description of the figures below.
Figure 1 shows an embodiment of a weaving device according
to the invention. The weaving device 1 comprises a shed formed by warp yarns 7,
whilst launching means 3 are disposed on one side (or both sides) of the shed 7
for inserting a weft yarn 8 in the form of a packed clew of yarn, which weft yarn
is at least partially enveloped by a carrier 9.
The launching means 3 consist of a launching tube 3, through
which the carrier 9 with the clew of yarn 8 is accelerated by means of a medium
under pressure, for example compressed air. Although this is not relevant for a
correct understanding of the invention, clamping means (not shown) are furthermore
provided, which hold the free end of the clew of yarn, so that the clew of yarn
extends from the moving carrier 9 to the weft yarn 8 during the flight of the carrier
9 through the shed 7.
The length of the weft yarn 8 is such that the front end
thereof is substantially in line with the right-hand side (in figure 1) of the shed
7. Receiving means 6 are disposed near the exit side of the shed 7 for receiving
the carrier 9, which is empty at that stage, for example for reuse thereof.
The carrier 9 is made of a very light material and constructed
so that the dimensions of the carrier substantially correspond to those of the clew
of yarn. Such a lightweight carrier 9 is difficult to control during its passage
through the shed and in order to influence the movement of the carrier 9 through
the shed - in order to avoid weaving flaws - the weaving device 1 is provided with
a guide 4, which forms part of the reed 2 in this embodiment. The reed 2 is built
up of a large number of lamellae 2a extending parallel to each other, which are
connected to the lay 2b.
Figures 3a-3c in conjunction with figures 4a-4d show various
operating situations of the weaving device according to the invention. As is shown
in the figures, the guide means 2, 2a, 5 are arranged for moving along with the
lay 2b upon passage through the shed 7 of the carrier 9 with the weft yarn 8 in
the form of a clew of yarn. The launching device 3 is stationary with respect to
the weaving device in these situations, such that the insertion direction of the
launching device extends parallel to the guide elements 2a (figure 3a).
Upon insertion of a carrier 9 with the clew of yarn 8 into
the shed by the launching device 3, the position of the lay 2b with the guide means
2, 2a, 5 with respect to the weaving device is as shown in figures 3a and 4a.
To keep the carrier within the passage formed by the individual
recesses 4 during its movement through the shed 7, auxiliary blowers 5 are provided,
which blow a medium under pressure, for example air, in the direction of the recess
4 via a jet orifice 5a. In this way the carrier 9 is prevented from undesirably
moving out of the recess 4 as a result of the erratic flight behaviour of the lightweight
carrier during its passage through the shed. Thus a force transversely to the insertion
direction is exerted on the carrier 9.
This is shown in subfigures 3b and 3c (figures 4b and 4c,
respectively). This ensures an improved control of the movement of the carrier 9
together with the weft yarn 8 in the form of a clew of yarn through the weaving
device. In one embodiment, the lay 2b with the frame 2, 2a, 5 returns to its starting
position in figure 3c (figure 4c) after insertion of the clew of yarn 8 and extension
thereof into a weft yarn, such that the outlet opening 3a of the launching device
3 and the open guide elements 2a or the guide channel formed by the recess 4 are
not aligned near the insertion side of the shed 7 at the moment when the carrier
9 exits the outlet opening.
In another embodiment, said forward movement of the lay
2b with the frame 2, 2a, 5 can take place at a moment when the carrier 9 is still
present in the recess 4 of the guide elements 2a that functions as a guide, as is
clearly shown in figure 4c (and figure 4d). Thus the weaving device can be prepared
more quickly for the next stroke, thereby realising a higher weaving speed.
As is shown in figures 6a-6c, the lamella-like elements
2a each have a recess 4 provided with an opening 4a, such that the recesses 4 of
adjacent lamella-like elements 2a form a guide channel 4 which is open on one side
of the shed 7. The carrier 9 can be guided through said guide channel, so that a
more stable movement through the shed 7 is realised and the occurrence of weaving
flaws is prevented or at least minimised.
In the embodiment that is shown in figure 1, the launching
means and in particular the launching tube 3 are arranged parallel to the direction
of movement of the carrier 9 through the shed 7. In another embodiment, however,
as shown in figure 5, the launching tube 3 may include an angle a with the launching
direction through the shed 7. By making said angle a adjustable, a velocity component
that is not parallel to the direction of movement of the carrier 9 through the shed
7 can be imparted to the carrier.
The movement of the carrier through the guide 4 and the
shed 7 may be further supported by using the auxiliary blowers 5 shown in figures
1 and 2, which are disposed beside the reed 2 in the shed 7. Said auxiliary blowers
5 direct a medium under pressure, for example an air jet, in the direction of movement
of the carrier and thus impart an additional velocity and direction component to
the carrier 9. On the one hand it is thus possible to bridge a comparatively large
distance in the shed 7 with the carrier 9, so that a simple and less robust construction
may be used for the launching means 3. On the other hand it is possible to correct
the movement of the carrier 9 through the shed 7 by means of the auxiliary blowers
5 by imposing a direction component on the carrier, resulting in a better retainment
of the carrier in the guide 4.
The auxiliary blower 5 may have a curved nozzle end 5a,
if desired, for directing an compressed air jet at the guide 4.
Figures 5a-5c likewise show various operating situations
of the carrier 9 being moved through the recesses 4 of the lamella-like elements
2a together with the weft yarn 8. The lamella-like guide elements 2a of which the
reed 2 is built up comprise two flange parts 11 a-11 b, in which a recess 4 is formed,
which recess is open on one side (numeral 4a). The recess 4 of an individual lamella-like
guide element 2a and the other recesses 4 of the adjacent lamella-like elements
2a jointly form the guide channel 4 for the carrier 9 and the weft yarn 8. The recess
4 has an open dimension at least larger than the diameter of the carrier 9.