WO1986007388A1

WO1986007388A1 - Tentering-perching machine for the treatment after drying of tanned hides

Info

Publication number: WO1986007388A1
Application number: PCT/IT1986/000040
Authority: WO
Inventors: Angelo Guarise
Original assignee: Officine Di Cartigliano S.P.A.
Priority date: 1985-06-05
Filing date: 1986-05-30
Publication date: 1986-12-18
Also published as: EP0259332A1; PT82708B; AU5960386A; DK44987A; IT1188010B; PT82708A; DK44987D0; IT8585560A0; KR880700082A; ES294597Y; ES294597U; CN86103861A

Abstract

The machine comprises a conveyor belt (1) which forward feeds each hide to be treated by engaging the hide between two drums (5-6) which are ribbed in opposite directions in order to operate the tentering and perching of said hide held by a gripper (2), which advances at reduced speed along guides (3) by the action of a drive device (4). The machine is optionally completed by a second pair of drums (7-8) associated to a second drive device (11) and to a second gripper (10), said drums (7, 8) providing for the working of the second half of each hide.

Description

EXTENDING-DRAWING MACHINE FOR THE AFTER-DRY TREATMENT OF TANNED SKIN -

The present invention relates to a machine intended to be used in the tanning industry in order to operate the enlargement and stretching of the skins, cold or hot, by passing between working rollers.

This machine was more specifically designed to bring together in a single phase the work of finishing the skins at the end of the process intended for their conditioning. In fact in this phase, the skins are presented in a rather rigid manner, in the stiffened state and with the shrunk fibers, so that in order to be able to pass to the final finishing phase, it is necessary to bring the skins back to a state of flexibility and fiber stretching, this operation is normally carried out using special machines.

Another operation developed immediately after, aims to widen the skins by stretching them as much as possible, in order to obtain the largest surface area, without however compromising the quality of the products. This operation is carried out with automatic so-called "finishing" machines which, taking advantage of the vacuum and the heating of the support surface, bring the skins to a temperature capable of predisposing them to be subjected to a mechanical enlargement action by maintaining between two vacuum rubber mats.

A third operation must be planned for buffing and ironing the hides on the "flower" side, this operation being carried out using machines with rotating cylinders.

It is easy to understand the advantages that a machine which, by means of a single operation, is able to carry out all the operations described above in a single time.

To this end, the machine according to the invention comprises at least one pair of drums rotating in opposite directions, which have inverted helical ribs suitable for interpenetration and between which the skin to be treated is caused to pass in order to undergo an action. compression and simultaneous progressive enlargement action directed from the center outwards. The free part of the skin is held in a appropriate clamp which advances with a conveyor belt at a speed lower than the driving speed of the two opposite rib drums, thereby ensuring complete elongation of the skin. In a first embodiment of the machine, particularly intended for the treatment of large skins, two pairs of rib drums are provided, arranged in series and fed by an input conveyor belt and by an output conveyor belt. The operating sequence of this first embodiment is as follows: The skin bears on the feed conveyor which, as a result of its movement, brings it close to the working drums. The stop is made using a line of photoelectric cells and at this moment the mobile clamp intervenes which, after having grasped the skin, advances it to engage it between the drums of the first pair, while the drums of the second pair are in the open position, allowing the skin to be transported by the second output belt using a second movable clamp which is in the standby position near the second pair of drums. This second clamp then closes by grasping the skin and driving it at the same speed as the first to bring said skin into the exit phase and control the reversal of the direction of penetration of the two pairs of rib drums, bringing the second pair of drums and discarding the first.

The second embodiment of the invention relates to a simplified machine for the treatment of skins of smaller dimensions. This variant, which falls within the scope of the invention, comprises a single pair of ribbed drums and a single conveyor belt provided with a single clamp which during work retains the skin adhering to the conveyor belt.

Of course in such a case, after having been treated for at least half of its length using a first pass, the skin must be put back on the feed conveyor belt again, but in the inverted position, and this by retracting the retaining clip, before being able to pass between the rib drums for the treatment of approximately the second half of its length. The appended drawing, given by way of example, will allow a better understanding of the invention, the characteristics which it presents and the advantages which it is capable of providing: FIG. 1 is a schematic side view showing a machine according to the first embodiment of the invention, said machine being provided with two conveyor belts, two clamps and two pairs of rib drums. Fig. 2 similarly shows a machine according to the second embodiment of the invention, this machine being equipped with a single conveyor belt, a single clamp and a single pair of rib drums.

Fig. 3 is a cross section showing a pair of rib drums. Fig. 4 is a perspective view showing two superimposed drums with their helical ribs or helices.

Fig. 5 is a detail view on a larger scale showing in the developed state the crossover area of the propellers presented by the two drums according to FIG. 4. In the first embodiment as illustrated in FIG. 1, the machine comprises a first conveyor belt 1 equipped with a retaining clamp 2 with linear movement which moves along horizontal guides 3 under the action of a drive mechanism 4 with belt and return pulleys. This conveyor belt 1 causes the skin to work, retained by the rear part using the clamp 2, between two opposed rib drums 5 and 6 which rotate in opposite directions and which are brought close to each other in the vertical direction indicated by arrows F ₁ and F ₂ . During this working phase, the drums 7 and 8 of a second pair are spaced apart from each other in the vertical direction indicated by the arrows F ₃ and F ₄ , so that they allow free passage the skin which is thus brought onto an outlet conveyor belt 9 where it is gripped by a second clamp 10, itself driven by a linear movement. When about half of the skin has been treated by the first pair of drums 5 and 6, these deviate from each other, always in the direction of the arrows F ₁ and F ₂ , while at otherwise the two drums 7 and 8 approach each other (arrows F ₃ and F ₄ ) thus being able to treat the skin which advances on the conveyor belt 9 while being pulled by the clamp 10, which is in turn set in motion by a driving device 11; of course the skin has been released by the clamp 2 which automatically returns to its starting position A. When the clamp 10 reaches the end of its stroke indicated in D, it controls its own opening and its return to the primitive position C, while the conveyor belt 9 continues in the same direction of movement to transfer outside the machine the skin thus softened and stretched both in the longitudinal direction and in the transverse direction.

The two clamps 2 and 10 having been brought back to positions A and C, the machine is thus ready for a new work cycle. Photoelectric cells 21 and 22 allow the movement of the drums 5, 6, 7 and 8 to be brought closer or apart during the passage of the skins.

In the variant embodiment illustrated in FIG. 2, the machine comprises a single conveyor belt 12 associated with a single clamp 13, movable along guides 14 under the effect of a drive device 15. There is also provided a single pair of rib drums 16 and 17 which rotate in opposite directions to grip the skin in order to stretch and soften it over about half of its length. A photoelectric cell 23, obscured by the passage of the skin during treatment, controls the bringing together of the drums 16 and 17.

Fig. 2 illustrates the starting position of a processing cycle. The clamp 13 is in position A ', while the conveyor belt 12 moves in the direction indicated, said clamp thus being brought to position B'. The skin bears on the moving carpet 12 and is thus advanced until it meets the axis of the cell 23 which stops said carpet and closes the clamp.

At this time and at a determined forward speed of the clamp 13, the skin engages through the two drums 16 and 17.

Once the clamp 13 has arrived at position B ′ its movement is reversed and it is therefore brought back to position

A ', after which said clamp opens, releasing the skin and allowing it to be turned over so that it can be worked on its second half.

As indicated above, this second type of machine lends itself especially to being used for the treatment of skins of smaller dimensions.

In fig. 4, one has shown in perspective one of the pairs of drums used in one and the other of the two machines described above, for example the drums 5 and 6. It may be noted that each drum has a first series of ribs helical which extends over one half of its length and another series of helical ribs on the other half, these ribs having opposite inclinations. In addition, the two drums of the same pair are ribs in opposite directions relative to each other. It is understood under these conditions that if these drums are rotated in opposite directions, as indicated by the arrows F ₅ and F ₆ , the skin 18 to be treated tends to be enlarged while being stretched for each of its two halves, from the center towards the periphery. In fig. 3, it can be observed that when the opposite drums, for example those assigned with references 5 and 6, are in the working position, that is to say with their axes close to each other, the ribs of one penetrates into the grooves of the other while the skin advances in the direction of the arrow F ₇ .

It will also be noted that the drums 5 and 6 of FIG. 3 are provided with heating means, for example of the induction type, which have been indicated very schematically by the references 19 and 20. These means ensure the uniform heating of the drums so as to bring them to the optimum temperature according to the characteristics of the skins to work.

Fig. 5 shows that the helical ribs 24, 25 and 26 of different lengths of the first half of the drum 5 are interposed between the ribs 27, 28, 29, themselves of different lengths, of the second half of the same drum. Similarly, the ribs 30, 31 and 32 of the first half of the drum 6 and the ribs 33, 34 and 35 of the second half of the same drum, all of different lengths and shown in broken lines in FIG. 5, inter wedge between the first so as to prevent the skin to be worked from wrinkling in the central zone and on the contrary being perfectly stretched at the level thereof.

Advantageously, it is expected that at least one of the drums of each pair 5-6 or 7-8 has, not a cylindrical profile, but may have a slightly biconical profile, that is to say with a diameter in the center. somewhat less than the diameter of each end. This arrangement ensures better stretching of the skin at the ends at the same time as it improves the flat shape of said skin. The degree of conicity is in any case quite reduced and it is determined according to practical experience.

In another alternative embodiment, it can be provided that in each pair of drums, while the upper drum in contact with the "flower" of the skin has ribs with rounded surface as shown in the drawing, the lower drum in contact with "the flesh" has more lively ribs, at the limit in the form of rectangular blades, so as to better compress the surface of the flesh in order to eliminate its roughness and to improve the final effect on the side considered .

It is easy to understand the advantages which can be obtained using the machine according to the invention which makes it possible to carry out stretching and softening of the skins, hot or cold, which clearly improves the characteristics multiple machines hitherto used to obtain an equivalent result. The tests demonstrated that the skins treated using the machine according to the invention exhibited greater flexibility and a more uniform stretch, while ensuring a better yield by increasing the useful surface of the skins.

It should moreover be understood that the foregoing description has been given only by way of example and that it in no way limits the field of the invention from which one would not depart by replacing the execution details described by all other equivalents.

Claims

1. Widening-stretching machine for the treatment after drying of tanned hides, characterized in that it comprises on the one hand at least one pair of drums (5, 6) which have helical ribs oriented in opposite directions from the center towards the periphery and which are arranged at the outlet of a conveyor belt (1) suitable for ensuring the advancement of each skin until its introduction between the aforementioned rollers, on the other hand at least one clamp (2) which grasps each skin by its rear edge during the advance of the belt (1) and which actuated by a driving device (4) advances said clamp at a speed lower than that of advance of the drums (5, 6) so cause stretching and enlargement of the skin during treatment.

2. Machine according to claim 1, characterized in that it comprises a second pair of drums (7, 8) capable, like the first ones, of being moved transversely (arrows F ₁ , F ₂ , F ₃ , F ₄ ) and associated a second conveyor belt (9) and a clamp (10) actuated by a driving device (11) in order to effect the stretching and the enlargement of the second half of each skin after the first pair of drums (5, 6) has been discarded while the second pair has been closed.

3. Machine according to claim 1, characterized in that it comprises a conveyor belt (12) which ensures the engagement of each skin between rotating drums ribs (16-17) which ensure the stretching and widening of the skin in the transverse direction with respect to its advance movement over approximately half the length of said skin, the latter then being taken in the inverted position by the clamp (13) in order to ensure stretching and l enlargement of the second half of the skin.

4. Machine according to claim 1, characterized in that the opposite drums of each pair (5-6 or 7-8) are provided with heating means (19-20), for example of the induction type, which uniformly raise the temperature of the drums up to the optimum temperature depending on the characteristics skins to be treated.

5. Machine according to claim 1, characterized in that the ribs (24, 25, 26), of different lengths, of a first half of one of the drums of each pair are interposed at different positions between the ribs ( 27, 28, 29), also of different lengths, of the second half of the same drum, while the ribs (30, 31, 32) of the first half of the opposite drum, themselves established at different lengths, are interposed with the former so as to prevent the skin during work from becoming thirsty, wrinkled in the central zone, thereby ensuring perfect stretching in said zone.

6. Machine according to claim 1, characterized in that at least one of the drums of each pair has, not a cylindrical profile, but a slightly biconical profile with a diameter in the center slightly smaller than that of each end, in order to '' operate a larger extension of the skin at said ends.

7. Machines according to claim 1, characterized in that in each pair of drums it is provided that the lower drum intended to come into contact with the "flesh" of the skin has more lively ribs, substantially in the form of rectangular blades while retaining the pitch and inclination of the rib, so as to improve the final appearance of the flesh.