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Title:
MOTOR-DRIVEN MECHANICAL SELVEDGE MACHINE
Document Type and Number:
WIPO Patent Application WO/2022/096922
Kind Code:
A1
Abstract:
Described is a motor-driven mechanical selvedge machine, including a containment casing (2), a foot-shear assembly (3), which grips and cuts to size a portion of weft thread coming out of the edge of a fabric being processed on a weaving machine and a needle assembly (4), equipped with a hook (5) around which the portion of the weft thread is wrapped to be dragged and folded towards the centre of the fabric and between the warp threads suitable for subsequent insertion of the weft. The control shaft (21) of the selvedge machine is connected to a servomotor (12), which is designed to move the selvedge machine in certain processing phases and to keep it stationary in other processing phases. The servomotor (12) is connected, by means of special connectors (13), to an electronic driver and is equipped with a first encoder, which continuously indicates the angular position of the servomotor (12) to the electronic driver. A second encoder is used to detect the movement of the weaving machine and maintain synchronism between the movement of the weaving machine and the movement of the selvedge machine.

Inventors:
SPEROTTO RINALDO (IT)
Application Number:
PCT/IB2020/060524
Publication Date:
May 12, 2022
Filing Date:
November 09, 2020
Export Citation:
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Assignee:
MANEA TEXTILE S R L (IT)
International Classes:
D03D47/48
Domestic Patent References:
WO1998028474A11998-07-02
Foreign References:
CN203625581U2014-06-04
CN201443007U2010-04-28
Attorney, Agent or Firm:
BURCHIELLI, Riccardo et al. (IT)
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Claims:
CLAIMS

1 . A motor-driven mechanical selvedge machine, comprising a containment casing (2), a foot-shear assembly (3) which provides for grasping and cutting to size a portion of a weft thread coming out from the edge of a fabric being processed on a weaving machine, a needle assembly (4), provided with a hook (5) around which said portion of the weft thread is wound to be dragged and folded towards the center of the fabric and between the warp threads in order to carry out a further insertion of the weft, said foot-shear assembly (3) and said needle assembly (4) being actuated by a drive shaft (21 ) of said selvedge machine, characterized in that said drive shaft (21 ) of said selvedge machine is connected to a servomotor (12) configured to move said selvedge machine during first processing steps and to keep said machine stopped during second processing steps, said servomotor (12) being connected, through suitable connectors (13), to an electronic driver and being equipped with a first encoder, which continuously indicates to said electronic driver the angular position of said servomotor (12), a second encoder being also used to detect the movement of said weaving machine and to maintain the synchronism between the movement of the selvedge machine and the movement of the weaving machine.

2. The selvedge machine as claimed in claim 1 , characterized in that said servomotor (12) is a brushless-type servomotor.

3. The selvedge machine as claimed in at least one of the previous claims, characterized in that said second encoder is a master encoder which synchronizes all the phases of the processing cycle of said weaving machine.

4. The selvedge machine as claimed in at least one of the previous claims, characterized in that a reduction element (14) is applied downstream said servomotor (12), so as to reduce the torque of the servomotor (12).

5. The selvedge machine as claimed in claim 4, characterized in that said reduction element (14) is a gear-type element.

6. The selvedge machine as claimed in claims 4 and 5, characterized in that said reduction element (14) has a pair of gears, so that said torque of the 6 servomotor (12) is reduced to 14 and said servomotor (12) operates with a speed which is equal to 4 times the speed of the selvedge machine.

Description:
MOTOR-DRIVEN MECHANICAL SELVEDGE MACHINE DESCRIPTION

This invention relates to the field of weaving, and in particular refers to an motor-driven selvedge machine.

More specifically, the invention relates to the improvement of a mechanical selvedge machine, suitable for any type of weft yarn (light, heavy, rigid, flexible, etc.), mechanically releasing the motion from that of the weaving machine on which it is mounted.

A fabric is an product obtained with a weaving machine (loom) by the interweaving between warp (row of yarns placed in longitudinal direction) and weft (yarn placed in transversal direction).

The weft is inserted by a vector (grippers, shell, air jet, water jet) into a compartment (shed or mouth) which is created by dividing the warp yarns into two high and low rows.

In modern weaving machines each weft yarn is cut at the two ends at a length a little longer than the width of the fabric; in this way, a 10-15 mm stretch of yarn protrudes on the two sides of the fabric, which in some good quality fabrics is not desired.

This is why special auxiliary machines, called selvedge machines, have been designed to be mounted at the edges of the fabric, which allow the protruding weft sections to be retracted into the fabric during weaving, in order to create a finished and stable edging (selvedge).

Selvedge machines are generally mechanical machines and normally comprise means of gripping and cutting the weft thread, to be inserted in the warp shed.

In practice, a needle is used to catch the end of the cut weft thread and make it re-enter, folded, into the warp mouth as soon as it has reopened for the next step, so that it can be beaten with the next weft, in order to make a retracted selvedge.

A machine of this type is known, for example, from patent document EP2800829A1.

There are also pneumatic selvedge machines, in which the shear is driven by a pneumatic cylinder and the return of the end is entrusted to a jet of air coming from the outside of the edge.

Whilst mechanical selvedge machines can be adapted to any type of weft thread (light or heavy, rigid or flexible), the use of pneumatic selvedge machines is limited to threads which are flexible and compliant enough to be bent by an air flow (wool, cotton, composite fibres, etc.).

On the other hand, the mechanical selvedge machines have the limit of being rigidly linked, through a mechanical transmission, to the weaving machine on which they are mounted.

This makes them unsuitable for certain types of fabric, such as for example a towelling sponge, in which the retraction of the weft head protruding from the fabric cannot be carried out at every insertion due to the fact that the comb contact is set back with respect to the insertion of the first two of three wefts and the retraction can therefore only be carried out at the third contact. As a result, the selvedge machine must remain stationary for two contacts and be activated only for the third contact. This operation can be obtained mechanically by disengaging and re-engaging the mechanical transmission by means of an element, such as a controlled joint, which must be maintained in phase with the position of the weaving machine and which is also subject to wear.

The main purpose of the invention is, therefore, to overcome the above- mentioned drawbacks of the prior art by making a motor-driven mechanical selvedge machine, whose motion is independent from that of the weaving machine on which it is mounted, so that it is adaptable to all types of fabric. Another aim of the invention is to make a selvedge machine which guarantees precision and operational and technological reliability, avoiding the use of mechanical transmissions and other mechanical components.

These and other aims, which will appear more clearly below, are achieved by an motor-driven selvedge machine, according to the attached claim 1 ; further technical characteristics are contained in the subsequent dependent claims.

Advantageously, according to the invention, the motion of the selvedge machine is mechanically disconnected from that of the weaving machine on which it is mounted, thus eliminating the mechanical transmission, by means of an electric shaft.

Further features and advantages of the motor-driven mechanical selvedge machine, according to the invention, will be more evident from the following description, referring to a preferred, but not limiting, example embodiment, and from the accompanying drawings, in which:

- Figure 1 is a perspective view of a mechanical selvedge machine, made according to the prior art;

- Figure 2 is a perspective view of a mechanical selvedge machine, made according to the invention;

- Figures 3 and 4 are two perspective views of some components of the mechanical selvedge machine, according to the invention.

With particular reference to Figure 1 , which shows a mechanical selvedge machine of the traditional type, reference numeral 2 denotes an external containment casing, numeral 3 denotes a foot-shear assembly, which grips and cuts to size the tail of the weft thread, which comes out from the edge of the fabric, whilst numeral 4 denotes a needle assembly, around the hook 5 of which the weft tail is wound to be dragged and folded towards the centre of the fabric, between the warp threads, prepared for the subsequent insertion of the weft.

As shown in detail in Figures 2, 3 and 4, according to the invention the transmission unit, consisting of the toothed pulleys 22, 25, toothed belt 23, belt tensioner 24 and drive shaft 20 of the weaving machine, is replaced by a servomotor 12 (brushless or equivalent), which is mechanically connected to the drive shaft 21 of the foot-shear assembly 3 and of the needle assembly 4 of the selvedge machine and connected, through connectors 13, to the electronic control driver (not shown in the drawings).

This allows the selvedge machine to move when needed and to keep it stationary during other steps.

The servomotor 12 is equipped with its own encoder or resolver (not illustrated), which continuously indicates its angular position to the electronic driver.

The synchronism between the movement of the selvedge machine and the movement of the weaving machine is ensured by the use of another encoder (not illustrated), which detects the movement of the weaving machine and which can also be the master encoder of the machine which synchronises all cycle phases.

Advantageously, in order to reduce the size of servomotor 12, with the same required power, it is possible to apply to the selvedge machine a reduction element 14, for example a gear-type element, positioned downstream of servomotor 12, which allows the torque of servomotor 12 to be reduced. For example, it is possible to apply a 1 :4 reduction, so as to reduce the torque of the servomotor 12 to , allowing it to operate at 4 times the speed of the selvedge machine, whilst remaining well below its maximum speed limit.

The choice to use a 1 :4 ratio is also dictated by the fact that it is possible to remain within the overall dimensions of the mechanical selvedge machine using only one pair of gears in the reduction element 14.

The characteristics of the motor-driven selvedge machine, according to the invention, clearly emerge from the description, as do the advantages thereof.

The invention thus conceived is in any case susceptible to numerous modifications and variations, all falling within the scope of the inventive concept of the attached claims; moreover, all the details may be replaced by other technically equivalent elements.

Where the characteristics and the techniques mentioned in the following claims are followed by reference signs, the reference signs have been used only with the aim of increasing the intelligibility of the claims themselves and, consequently, the reference signs do not constitute in any way a limitation to the interpretation of each element identified, purely by way of example, by the signs numbers.