EP0274676B1

EP0274676B1 - Device to piece up rovings of textile fibres

Info

Publication number: EP0274676B1
Application number: EP87118296A
Authority: EP
Inventors: Piero Bigagli
Original assignee: S BIGAGLI AND C SpA
Current assignee: S BIGAGLI AND C SpA
Priority date: 1987-01-15
Filing date: 1987-12-10
Publication date: 1995-11-02
Anticipated expiration: 2007-12-10
Also published as: IT8783302A0; EP0274676A1; ES2080718T3; DE3751577D1; IT1214141B; DE3751577T2

Description

This invention concerns a device suitable for the piecing-up of rovings of textile fibres.
The invention concerns also spinning machines which employ such device.
The invention is properly employed in piecing-up rovings on spinning machines for carded and combed yarns, the fibres of the rovings being free of substantial twists.
More particularly, the piecing-up device is fitted to spinning machines equipped with automatic systems for changing the rolls of roving or packages of yarn being fed.
There are already known in the prior art methods and devices to piece-up roving which are applied to spinning machines.
According to IT 83351 A/85 (EP-A-0.196.127) of the present applicant with regard to a device applied to carded yarn, the heads or tails of the roving are positioned on an aspiration grill, and the aspiration effect causes the fibres of the two ends of the roving to become intermingled and thus generates the actions of bonding and piecing-up the roving.
The above solution produces a splice which often lacks sufficient strength and leads to breakage of the roving and interruption of the spinning process.
In general the known devices can hardly be used for piecing-up rovings where automatic systems are employed, such as the automatic change of the rolls or roving or yarn packages being fed.
The present invention eliminates such drawbacks, thus obtaining a resistant splice and improving the efficiency of the automatic systems for changing the rolls of roving and packages of yarn being fed.
The invention therefore tends to make the operations of the spinning machine more reliable.
This is achieved by means of a spinning machine having the features described in Claim 1, while the dependent claims describe advantageous forms of embodiment of the invention.
The device according to the invention consists of a chamber into which nozzles deliver fluid under pressure to obtain the piecing-up of the roving.
This chamber consists of two parts called half-chambers, which are coupled together momentarily during the piecing-up step.
The first of the two half-chambers is rigidly attached to the structure of the spinning machine and is connected to the working elements which perform the spinning cycle. The roving being processed lies continuously in the first half-chamber.
The second half-chamber is solidly fixed to the movable means which change the rolls of roving automatically.
The head of the roving coming from a full roll is positioned in this second half-chamber by means of a gripper or a like element having the same function as a gripper.
The momentary coupling together of the first and second half-chambers provides a piecing-up chamber, which consists conveniently of a cylindrical cavity. This cavity stretches lengthwise along the whole length of the chamber, thus enabling the fluid under pressure to flow out laterally.
In the step before the piecing-up the rovings to be united are contained in each of the two half-chambers and are therefore brought near to each other at the moment when the half-chambers are coupled together to form the piecing-up chamber.
The device obtains the piecing-up of the rovings by the fluid-dynamic action of at least one flow of air under pressure introduced into the piecing-up chamber by nozzles solidly fixed advantageously to the second movable half-chamber.
Such nozzles are suitably positioned and oriented in relation to the piecing-up chamber and act with a fluid-dynamic action on the terminal portions of the rovings in a direction substantially at a tangent to those portions.
The fluid-dynamic actions can be oriented in differentiated directions, for instance one to the right and the other to the left.
The piecing-up is obtained by twisting the ends of the rovings on each other and interlacing the fibres of the same.
In a variant the piecing-up is carried out with one single nozzle suitably positioned and oriented in relation to the piecing-up chamber.
In a further variant both the half-chambers contain nozzles.
According to a preferred embodiment of the invention the piecing-up chamber is cylindrical and has a smooth inner surface.
In a variant such inner surface is grooved and the grooves may cover a part or the whole of the axial length of the chamber.
In another variant the inner surface has a helicoidal profile, which may extend along a part or the whole of the axial length of the chamber.
Such grooved or helicoidal surfaces cause the fluid under pressure to flow according to controlled circumferential trajectories.
In a variant the piecing-up chamber has a lengthwise prismatic shape, the base of the prism being a convenient flat figure.
In another variant the generating lines of the chamber are straight but not parallel to the axis of the chamber.
In a further variant the generating lines of the chamber are not straight.
The attached figures, which are given as a non-restrictive example, show the following:-

Fig. 1: shows a perspective of an embodiment according to the invention;
Fig. 2: gives a front view of the embodiment of Fig.1;
Fig. 3: shows a lengthwise section of the embodiment of Fig.1;
Fig. 4: shows a variant;
Figs. 5, 6 and 7: show variants of the inner surface of the chamber;
Fig. 8: shows diagrammatically a section of a spinning machine with the device of the invention attached.

The device comprises a chamber 10 consisting of two parts which are momentarily coupled together, namely a first half-chamber 11 and a second half-chamber 12.
In the example shown the first half-chamber 11 is solidly fixed to the structure of a spinning machine 13 (Fig.8) and lodges permanently roving 14 being processed, which feeds a package of spun yarn 15.
Such first half-chamber 11 cooperates with a means 19 that shears the roving 14 during the step of introducing a new roll of roving 18 when the previous roll 118 is exhausted.
In the example shown the second half-chamber 12 is solidly attached to movable elements which change the rolls of roving 18-118 automatically and, in particular, to a movable rod 17 connected to means which handle the full rolls of roving 18.
As we said earlier, the inner surface of the chamber 10 consisting of two half-chambers 11-12 advantageously has a roughness less than 3.2 micrometres.
The diameter D of the chamber 10 may range between 5 and 20 mm., depending on the properties of the roving 14 being processed.
The second half-chamber 12 comprises nozzles 21 fed with a fluid under pressure. During the coupling of the two half-chambers the feed of fluid may be continuous or pulsating or else may have a momentarily variable value.
In the example of Fig.2 the fluid acts according to the arrows and generates torques in opposite directions.
The nozzles 21 act in two separate positions in the chamber 10 along axes 22 and 23, which are positioned at a distance apart from each other of between 10 and 100 mm.,depending on the propoerties of the rovings 14 and 114.
The axes 22-23 form between them an apparent angle B which may vary between 0° and 120°; the present applicant has found that a value in the neighbourhood of 60° is best.
Each of the axes 22-23 may possibly intersect the lengthwise axis 24 of the chamber 10.
Each of the axes 22-23 (Fig.3) forms together with the lengthwise axis 24 of the chamber 10 an actual or apparent angle A which will vary advantageously between 90° and 120°.
The diameter of the nozzles 21 is selected to suit the properties of the rovings 14-114, as also is the maximum and/or minimum pressure of the fluid supply.
The second half-chamber 12 comprises terminal grippers 25 and 26 to retain the roving 114 of the replacement roll for performance of the automatic change of the rolls of roving. Such grippers 25-26 consist of elements 27-28 and 127-128 fitted so as to be able to oscillate on pivots 29 at the two ends of the chamber 10.
The elements 27-127 and 28-128 are connected together with attachment rods 30; a resilient element 31 is advantageously included which is able to apply a resilient return force to the rods 30.
The grippers 25-26 have two positions of stable equilibrium.
The grippers 25-26 retain the new roving 114 until the moment when the two half-chambers 11-12 are coupled together; the half-chambers do not hinder the formation of the splice, nor do they damage the splice when made.
In the example shown the opening of the grippers 25-26 and resulting release of the new roving 114 are obtained by the encounter of the grippers 25-26 with abutment pins 16 rigidly connected to the first half-chamber 11.
When the grippers 25-26 have opened, the nozzles 21 enter into action and separate the new roving 114 from the grippers 25-26.
In a variant (Fig.4) there is only one nozzle 121, which is positioned suitably in one portion of the chamber 10; such portion may be varied as required, the nozzle 121 being oriented according to an angle B in relation to the lengthwise axis of the chamber 10.
In the example shown in Fig.4 the first half-chamber 111 is so conformed that it can itself open the gripper elements 227-228, which themselves constitute the second half-chamber 112.
Figs.5 to 7 show variants of the inner surface 20 of the chamber 10.
Fig.5 shows as an example grooved chamber surfaces obtained by rotating dies having teeth of a rectangular (5a), trapezoidal (5c) or triangular (5b) shape about the lengthwise axis 24 of the chamber 10.
Fig.6 shows helicoidal surfaces obtained by rotating dies having teeth of a rectangular (6a), trapezoidal (6c) or triangular (6b) shape about the lengthwise axis 24 of the chamber 10 and by traversing such dies at the same time in the direction of the above axis 24.
Fig.7 shows as an example surfaces of the same types as 5a and 6c but with an intermediate cylindrical segment (7a and 7b).

Claims

Device to piece up rovings of textile fibres on a spinning machine for carded or combed yarns, equipped with an automatic system for changing the rolls of roving being fed, comprising a piecing-up chamber (10) consisting of a first half-chamber (11) solidly fixed to the structure of the spinning machine (13) and a second half-chamber (12) connected to a movable element (17) of said automatic system, whereby such half-chambers (11-111, 12-112) are coupled together momentarily when such movable element (17) is moved in an actuating position, the first half-chamber (11-111) containing permanently the roving being processed, whereas the second half-chamber (12-112) comprises grippers (25-26) which retain the roving (114) of a full roll (18) until the moment when the two half-chambers (11-12) are coupled together, and at least one nozzle (21-121) to deliver fluid under pressure into the piecing-up chamber which enters into action when the grippers (25-26) have opened.
Device as in Claim 1, in which the second half-chamber (12-112) comprises at least two nozzles (21) to deliver fluid which are positioned in different portions of the piecing-up chamber (10).
Device as in Claim 1 or 2, in which the axes of the nozzles (21) form between them an apparent angle "B" which may vary between 0° and 120° (Fig.2).
Device as in any claim hereinbefore, in which the apparent angle "B" is 60° (Fig.2).
Device as in any claim hereinbefore, in which the nozzles (21-121) lie along a line at a tangent to the surface of the chamber (10).
Device as in any claim hereinbefore, in which the axes of the nozzles (21) together with the lengthwise axis (24) of the chamber (10) form an actual or apparent angle "A" which may vary between 90° and 120° (Fig.3).
Device as in any claim hereinbefore, in which the grippers (25-26) constitute the second half-chamber (112).
Device as in any claim hereinbefore, in which the first half-chamber (11-111) comprises abutment means (16) to open the grippers (25-26).
Device as in any of Claims 1 to 6 inclusive, in which the first half-chamber (111) itself constitutes an abutment means to open the grippers (25-26).
Device as in any claim hereinbefore, in which the piecing-up chamber (10) has a smooth inner surface (20) with a roughness less than 3.2 micrometres.
Device as in any of Claims 1 to 8 inclusive, in which the inner surface (20) of the chamber (10) is at least partially grooved.
Device as in any of Claims 1 to 8 inclusive, in which the inner surface (20) of the chamber (10) is at least partially helicoidal.
Device as in any of Claims 1 to 8 inclusive and in Claim 11, in which the inner surface (20) of the chamber (10) comprises two zones having opposed helicoidal grooves (Fig.7b).
Spinning machine for carded or combed yarns equipped with a system for the automatic changing of rolls of roving, which comprises a device to piece-up the rovings fed, the device comprising a piecing-up chamber (10) consisting of a first half-chamber (11-111) solidly fixed to the structure of the spinning machine (13) and a second half-chamber (12-112) connected to a movable element (17) of said system, the two half-chambers (11-111, 12-112) being coupled together momentarily when such movable element is moved in an actuating position, the first half-chamber (11-111) containing permanently the roving being processed, whereas the second half-chamber (12-112) comprises grippers (25-26) which retain the roving (114) of a full roll (18) until the moment when the two half-chambers (11-12) are coupled together, and at least one nozzle (21-121) to deliver fluid under pressure into the piecing-up chamber which enters into action when the grippers (25-26) have opened.