Combing machine with variable speed circular comb

Abstract

 A combing machine envisages, between a motor (21) and a circular comb (20), a transmission device (30) having in input a motor shaft (36) with angular input speed (Win) and in output a driven shaft (19) with angular output speed (Wout), engaged with the circular comb (20). The ratio (R) between the angular output speed (Wout) and the angular input speed (Win) being defined, said ratio is variable depending on the angular position (α) of the circular comb and is between 1.55 and 0.45. In particular the ratio (R) depending on the angular position (α) is defined by the graph shown in figure 7.

Description

[0001] The present invention relates to a combing machine of a spinning line for processing fibre to obtain a yarn.

[0002] On a fibre processing line for the production of yarn, after the initial phases of opening and cleaning the fibre, carding is performed by carding machines, after which the fibre appears in the form of a web.

[0003] After processing, if any, on a lap-winder, in which various separate webs are combined to form a lap, the web or lap is combed by a combing machine, so as to obtain a web in which the fibres have been rendered highly clean and parallel.

[0004] Combing is performed by circular combs, which are used to comb the heads of the tufts of the lap, and by straight nipper combs, used to comb the tails of the same tufts of the lap. The combed tufts are fed to the tearing rollers, situated downstream of the combs, so that the edges overlap; the continuous web formed proceeds for subsequent processing.

[0005] The circular comb is provided with a continuous rotatory movement, synchronised with the alternate movement of the nipper, so as not to interfere structurally with it.

[0006] It is therefore extremely advantageous for the circular comb to have a variable rotation speed, so that rotation is slower when the nipper is near the tearing rollers (and the circular comb is therefore idle) and faster when the circular comb combs the fibre (and the nipper is therefore distant from the tearing rollers) and when the tearing rollers move the already previously combed tuft backwards for overlapping with the new one. By so doing, timing is optimised, reducing the dynamic severity of the movements, in particular of the tearing rollers, and paying particular attention in any case to avoiding structural interference between the circular comb and the nipper.

[0007] Solutions of circular combs with variable speed rotatory movements exist. For example, one embodiment is described in the International Application WO 2011/073942 in the name of the Applicant.

[0008] The purpose of the present invention is to make a combing machine with variable speed circular combs having a law of motion permitting an optimal combing to be performed, maintaining a high level of reliability of functioning and of the mechanical components used to achieve such law.

[0009] Such purpose is achieved by a combing machine according to claim 1 below.

[0010] The characteristics and advantages of the combing machine according to the present invention will be evident from the description below, made by way of a non-limiting example, with reference to the appended drawings, wherein:

[0011] - figure 1 shows a diagram of a combing machine, in a rearward position of the nipper, corresponding to an initial angular position of the circular comb (0° or 360);

[0012] - figure 2 shows the diagram of figure 1, in a forward position of the nipper, corresponding to an initial angular position of the circular comb opposite the position as in figure 1 (180°);

[0013] - figure 3 shows a kinematic diagram of a combing machine according to the present invention, according to one embodiment;

[0014] - figure 4 shows a transmission device of the combing machine, according to one embodiment,

[0015] - figure 5 shows the trend of the angular output speed of the transmission device depending on the angular position of the circular comb;

[0016] - figure 6 shows the trend of the angular output acceleration of the transmission device depending on the angular position of the circular comb; and

[0017] - figure 7 shows the trend of the ratio of the angular output speed to the angular input speed of the transmission device depending on the angular position of the circular comb.

[0018] A combing machine according to the invention comprises a fixed frame 2, a nipper 4 and a circular comb 20.

[0019] The nipper 4 comprises a lower jaw 6 and an upper jaw 8; the nipper 4 further comprises a straight comb 10, suitable for combing the tail of the tuft.

[0020] In addition, the nipper 4 comprises a rotating feed roller 12, supported by the lower jaw 6.

[0021] Downstream of the nipper 4, are pairs of tearing rollers 14, 16, having an alternate rotatory movement.

[0022] The nipper 4 has an alternate back and forth movement; in a forward position, the nipper occupies a processing zone and the jaws 6, 8 are next to the tearing rollers 14, 16 and open; in a rearward position of the nipper, the jaws 6, 8 are distal from the tearing rollers 14, 16 and closed, so as to nip the web being processed.

[0023] The circular comb 20 is joined in rotation to a main shaft 18 and has a continuous rotatory movement. The circular comb 20 operates on the head of the tuft of the web when it transits immediately upstream of the tearing rollers, in other words through the processing zone.

[0024] The rotatory movement of the circular comb 20 is synchronised with the alternate movement of the nipper 4, so that when the nipper is in the forward position, in other words in the processing zone immediately upstream of the tearing rollers, the comb 20 is inactive, that is to say outside the processing zone; when the nipper is in the rearward position, in which the jaws do not occupy the processing zone, the comb is in said processing zone and performs combing of the head of the tuft.

[0025] The combing machine further comprises an electric motor 21 able to impose an angular speed and a kinematism 22 for the transmission of the rotatory movement from the motor 21 to the main shaft 18.

[0026] The kinematism 22 comprises a transmission device 30 suitable for varying a uniform circular movement in input into a non-uniform circular movement in output, transmitting it to the main shaft 18.

[0027] According to one embodiment, the transmission device 30 comprises an intermittent drive, in particular of the flat type, comprising a first body or motor body 52, joined in rotation to the motor shaft 36 having an angular input speed Win, and a second body or driven body 54, joined in rotation to the driven shaft 19, having an angular output speed Wout; the driven body 54 meshing permanently with the motor body 52.

[0028] The term "intermittent drive" indicates herein a transmission wherein the motor body is composed of one or more cams and the driven body is composed of a plate bearing a series of rollers which form a shaped coupling with the cam at all times.

[0029] One of the two bodies 52, 54, for example the motor body 52, is shaped so as to form a plurality of lobes connected with each other. The other of the two bodies 52, 54, preferably the driven body 54, comprises a plurality of angularly spaced rollers 64, at least one of which is engaged with the other body 52, to ensure the transmission of movement to the driven shaft 19.

[0030] In particular the motor body 52 is shaped so as to ensure a variable speed circular movement to the driven body 54, for example a continuous circular movement.

[0031] Figure 5 shows the angular output speed Wout of the driven shaft 19 (and therefore of the circular comb 20, in the embodiment shown) depending on the angular position α of the motor shaft 36 (and therefore of the circular comb 20) and depending on the angular input speed Win (constant and equal to 500 rounds /min).

[0032] The maximum angular output speed (Wout) is less than 800 rounds/minute, in particular less than 700 rounds/minute, approximately equal to 670 rounds/minute.

[0033] The minimum angular output speed Wout is more than 200 rounds/minute, in particular more than 300 rounds/minute, approximately equal to 330 rounds/minute.

[0034] Figure 5 also shows the angular output speed Wprior of a known combing machine, extracted experimentally on a combing machine of a rival company.

[0035] Figure 6 shows, depending on the angular position α, the angular output acceleration Aout of the driven shaft 19 (and therefore of the circular comb 20).

[0036] The maximum angular output acceleration Aout is less than 1500 rad/s2 and the minimum angular output acceleration Aout is more than -1500 rad/s2.

[0037] In particular the maximum angular output acceleration Aout is less than 1200 rad/s2, for example approximately equal to 1000 rad/s2, and the minimum angular output acceleration Aout is more than -1200 rad/s2, for example approximately equal to -1000 rad/s2.

[0038] Figure 6 also shows the angular output acceleration Aprior of a known combing machine, extracted experimentally on a combing machine of a rival company.

[0039] Figure 7 shows, depending on the angular position α, the ratio R of the angular output speed Wout to the angular input speed Win of the transmission device.

[0040] The maximum ratio R is less than 1.55, and in particular less than 1.40, and about equal to 1.35.

[0041] The minimum ratio R is more than 0.45, and in particular more than 0.60, and about equal to 0.65.

[0042] Figure 8 also shows the ratio Rprior of the angular output speed to the angular input speed of a known combing machine, extracted experimentally on a combing machine of a rival company.

[0043] Innovatively, the transmission device of the combing machine according to the present invention, makes it possible to perform a particularly efficient combing, in that during the active phase of the circular comb, the angular speed is not excessively high, so that the fibres are not subject to an overly energetic action. This results in a higher quality of the finished product.

[0044] Advantageously, moreover, the angular output speed of the circular comb undergoes a limited variation during a combing cycle, so that the components of the kinematic system are subject to lesser forces of inertia. This results in a high level of machine reliability.

[0045] It is clear that a person skilled in the art may make modifications to the transmission device described above so as to satisfy contingent requirements while remaining within the sphere of protection of the following claims.

Claims

1. Combing machine (1) comprising:

- at least one pair of tearing rollers (14,16) suitable to rotate in alternating motion;

- a nipper (4) suitable to perform a back and forth movement from the pair of tearing rollers (14,16), between a forward position in which it is close to said rollers and positioned in an area of engagement with these, and a rearward position in which it is distanced from said rollers;

- a circular comb (20) moved in rotation in a synchronised manner with the movement of the nipper;

- a transmission device(30) having in input a motor shaft (36) movable in rotation with angular input speed (Win) and in output a rotatable driven shaft (19) with angular output speed (Wout) and kinematically engaged with the circular comb (20);

wherein, the ratio (R) between the angular output speed (Wout) and the angular input speed (Win) being defined, said ratio is variable depending on the angular position (α) of the circular comb and is between 1.55 and 0.45.

2. Combing machine according to claim 1, wherein said ratio (R) is between 1.40 and 0.60.

3. Combing machine according to claim 2, wherein said maximum ratio (R) is about 1.35 and said minimum ratio (R) is about 0.65.

4. Combing machine according to any of the previous claims, wherein said ratio (R) depending on the angular position (α) is defined by the graph shown in figure 7.

5. Combing machine according to any of the previous claims, wherein the angular output speed (Wout) is between 200 rounds/minute and 800 rounds/minute, preferably between 700 rounds/minute and 300 rounds/min.

6. Combing machine according to claim 5, wherein the angular output speed (Wout) depending on the angular position (α) is defined by the graph shown in figure 5.

7. Combing machine according to any of the previous claims, wherein the angular output acceleration (Aout) is between 1500 rad/s² and -1500 rad/s², preferably between 1200 rad/s² and -1200 rad/s².

8. Combing machine according to claim 7, wherein the angular output acceleration (Aout) depending on the angular position (α) is defined by the graph shown in figure 6.

9. Combing machine according to any of the previous claims, wherein the transmission device comprises a flat intermittent drive (30).

10. Combing machine according to claim 9, wherein the intermittent drive comprises a driven body (54) or second body, fitted with angularly spaced rollers loosely mounted in rotation and a first body (52) such as a motor body (52), joined in rotation to the electric motor (21) and permanently meshing with the driven body, provided with angularly spaced lobes.

Drawing