Improved staking machine

Abstract

An improved staking machine (1) for softening and stretching flexible laminar products, such as industrial leathers and the like which have opposite sides, the machine comprising at least one pair of beating plates (6, 7) facing each other and configured to act on the opposite faces of the laminar products, motorized advancement means (5) for conveying the products along a predetermined longitudinal direction (L) and comprising at least one upper elastic belt (8) and at least one lower elastic belt (9) facing each other. The elastic belts (8, 9) have an annular extension and they are wound respectively on at least one pair of upper end rollers (10, 11) and one pair of lower end rollers (12, 13). The advancement means (5) comprise a first (14) and a second electric motor (15) respectively coupled to an upper end roller (10, 11) and a lower end roller (12, 13), to allow said elastic belts (8, 9) to advance at the same advancement speed (v1, v2) regardless of the elongation of each individual belt over time and to keep the interposed laminar products perfectly flat, stretched and free from creases and unevenness during advancement thereof.

Description

IMPROVED STAKING MACHINEDESCRIPTIONField of the invention

[0001] The present invention is applicable to the general field of machinery for the tanning industry and it particularly relates to an improved staking machine for softening and stretching flexible laminar products.Background art

[0002] In the tanning industry, there has been long known the use of machines called stacking machines, designed to carry out softening and stretching of flexible laminar products such as industrial leathers and similar products which have opposite faces called grain side and flesh side.

[0003] These machines are used in operations subsequent to tanning and / or drying operations so as to allow the product to reacquire a natural softness, besides increasing the extension, that is the “footing”.

[0004] Generally, these machines comprise at least one pair of beating plates which are arranged facing each other and configured to act on the opposite faces of the laminar products with an alternating motion, to mutually approach and move away in a direction substantially perpendicular to the faces of the product.

[0005] Each plate is further provided with tools or rungs adapted to interact with corresponding cavities or recesses having a complementary shape and arranged on the opposite plate.

[0006] Typically, a staking machine comprises motor-driven advancement means for the products to be processed along a predetermined direction, for example formed by a pair of elastic belts with annular extension arranged facing each other and between which there are interposed laminar products to be stacked.

[0007] Such advancement means comprise an upper elastic belt and a lower elastic belt wound respectively on at least one pair of upper end rollers and a pair of lower end rollers.

[0008] The elastic belts serve not only for driving the laminar products as they advance between the beating plates, but also for keeping the products being processed well stretched on the entire surface extension thereof avoiding creases and curling as much as possible.

[0009] Thus, for processing purposes, it is very important that the elastic belts may advance at the same advancement speed especially at their mutually facing areas.

[0010] However, over time and due to the transversely directed stress induced by the beating plates, the elastic belts partly lose their initial elastic properties and, as a result, they tend to loosen and slide at speeds different from the predetermined ones.

[0011] As a result, the feeding efficiency for the laminar products is partly reduced, and, in borderline cases, the products are fed into the machine in a non-even manner, facilitating the formation of processing creases and defects such to make the finished product unusable.

[0012] As a matter of fact, if an elastic belt advances at a different speed with respect to the other belt, the laminar product advances along the machine with the presence of transverse creases which lead to the formation of surface defects on the processed product.

[0013] Accordingly, a drawback of these prior stacking machines lies in the fact that the laminar products interposed between the upper belt and the lower belt may curl or fold and they do not remain perfectly stretched.Technical problem

[0014] In the light of the prior art, the object of the present invention is to solve the technical problem of providing a staking machine which allows an effective and optimum adjustment of the advancement speed of both elastic belts automatically and their adaptation to the needs of the processing operations on the products to be processed, in such a manner to avoid processing creases and defects.Summary of the invention

[0015] An object of the present invention is to solve the aforementioned problem and overcoming the drawbacks of the prior art by providing a staking machine for softening and stretching flexible laminar products which is highly effective and cost-effective.

[0016] A particular object of the present invention is to provide a staking machine of the type indicated above which allows to adjust the advancement speed of the elastic belts automatically and accurately as required for the specific type of product.

[0017] Another object of the present invention is to provide a staking machine of the type indicated above which allows to confer to the belts an advancement speed such to avoid the slipping of the laminar products and ensure the even processing thereof.

[0018] A further object of the present invention is to provide a staking machine of the type indicated above which avoids the curling of the laminar products and formation of transversal creases on the products being processed.

[0019] Another object of the present invention is to provide a staking machine of the type indicated above which allows to reduce waste.

[0020] The objects mentioned above and others which will be more apparent hereinafter, are achieved by a staking machine for softening and stretching flexible laminar products, such as industrial leathers and the like which have opposite faces, as claimed in claim 1 .

[0021] The machine comprises at least one pair of beating plates which are arranged facing each other and configured to act on the opposite faces of the laminar products and motorized advancement means for conveying the products along a predetermined longitudinal direction and comprising at least one upper elastic belt and at least one lower elastic belt which are arranged facing each other.

[0022] The elastic belts have an annular extension, and they are wound respectively on at least one pair of upper end rollers and a pair of lower end rollers.

[0023] According to a peculiar aspect of the invention, the advancement means comprise a first and a second electric motor respectively coupled to an upper end roller and a lower end roller, so as to allow said elastic belts to advance at the same advancement speed regardless of the elongation of each single belt over time and for keeping the laminar products interposed perfectly flat, stretched and free from creases and unevenness during advancement thereof.

[0024] Thanks to this combination of features, the machine allows an effective and optimum adjustment of the advancement speed of both elastic belts automatically and adapting them to the processing needs of the products to be processed, so as to prevent processing creases and defects.

[0025] In one embodiment, each electric motor of the pair is coupled to a respective end roller by means of a respective direct gearmotor.

[0026] According to the invention, the machine comprises electronic control means connected to the advancement means to change the advancement speed of the laminar products.

[0027] The electronic control means comprise a pair of electric sensors adapted to respectively detect the rotation speed of an upper end roller and of a lower end roller and configured to generate first and second electrical signals.

[0028] Furthermore, the pair of electric sensors comprises an upper sensor and a lower sensor which are respectively associated with an upper idle end roller and with a lower idle end roller.

[0029] The electronic control means comprise an encoder associated with a respective gearmotor configured to generate the position electrical signals.

[0030] As a matter of fact, the machine comprises a microcontroller electronic unit on which there is installed a computer program configured to receive the electrical signals and process them to automatically adjust the advancement speed of the elastic belts and keep them constantly equal to the reference advancement speed values.

[0031] Advantageous embodiments of the invention are conceived according to the dependent claims.Brief description of the drawings

[0032] Further features and advantages of the invention will be more apparent in the light of the detailed description of a preferred but not exclusive embodiment of a staking machine for softening and stretching flexible laminar products like the one mentioned above, shown by way of non-limiting example with the aid of the following drawings wherein:FIG. 1 is a lateral view of a staking machine according to the prior art;FIG. 2 is a lateral view of a staking machine according to the invention;FIG. 3 is an enlarged lateral view of a detail of the machine of Fig. 1 , according to the prior art;FIG. 4 is an enlarged perspective view of a detail of the staking machine of Fig. 2 according to the invention;FIG. 5 schematically shows the flow chart for the operation of the staking machine of Fig. 2.Detailed description of a preferred embodiment

[0033] With particular reference to the figures mentioned above, there is shown a staking machine, globally indicated with the reference numeral 1 , configured to soften and stretch flexible laminar products, not shown in the figures, such as industrial leathers and the like which have opposite faces.

[0034] The staking machine 1 comprises a base 2 adapted to define an inlet area 3 for the inlet of the products to be treated and an outlet area 4 for the outlet of the treated laminar products and motorized advancement means 5 for conveying the products along a predetermined longitudinal direction L from the inlet area 3 to the outlet area 4.

[0035] The machine 1 further comprises at least one pair of beating plates 6, 7 facing each other and substantially parallel to the advancement means 5 and configured to act on the opposite faces of the laminar products being processed.

[0036] The upper plate 6 may comprise a plurality of rung-shaped tools, not shown in the figures, while the lower plate 7 may comprise a plurality of cavities or holes, also not shown in the figures, that have a complementary shape and aligned with respect to the rungs.

[0037] During the working, the upper plate 6 is fixed and the lower plate 7 is movable and is connected to drive means, not shown in the figures. The latter impart to the movable plate 7 a reciprocating approaching and moving away motion with respect to the fixed plate 6 with a predetermined number of beats.

[0038] In a per se known manner, the upper plate 6 may be moved to allow the adjustment of the penetration level of the plurality of rungs compared to the respective plurality of cavities or holes, generally comprised between 0 and 10mm.

[0039] The beating plates 6, 7 interact at the time of the beating to exert with the rungs and the holes a pressure of a predetermined value on the advancing laminar products.

[0040] Obviously, the tools may also be different or they may have a different order, with the holes formed on the fixed plate 6 and the rungs formed on the movable plate 7, without departing from the scope of protection of the present invention.

[0041] The advancement means 5 comprise at least one upper elastic belt 8 and at least one lower elastic belt 9 facing each other and with mutual contact, interposed between the pair of beating plates 6, 7 to retain and advance the products along a longitudinal direction L.

[0042] The upper elastic belt 8 has an annular extension and it is wound on a pair of upper end rollers 10, 11 having transverse and parallel rotation axes.

[0043] Similarly, the lower elastic belt 9 has an annular extension and it is wound on a pair of lower end rollers 12, 13 also having rotation axes that are transverse and parallel to each other and to the upper end rollers 10, 11.

[0044] The pair of elastic belts 8, 9 may have respective substantially straight and horizontal portions 8A, 9A facing each other to retain the laminar productsinserted into the inlet area 3 of the machine 1 and advance them towards the outlet area 4.

[0045] As a matter of fact, the elastic belts 8, 9 allow to drive the laminar products during advancement thereof between the beating plates 6, 7 and keep the products being processed well stretched throughout their surface extension so as to avoid creases and curling.

[0046] Thus, for processing purposes, it is very important that the belts 8, 9 may advance at equal speed vi, V2 especially at their mutually facing portions 8A, 9A

[0047] It is known that, over time and due to the transversely directed stress induced by the beating plates 6, 7, the elastic belts 8, 9 partly lose their initial elastic features and, as a result, they tend to loosen and slide at speeds vi, V2 different from the predetermined ones.

[0048] According to a peculiar aspect of the invention, the advancement means 5 comprise a first 14 and a second electric motor 15 respectively coupled to an upper end roller 10, 11 and to a lower end roller 12, 13.

[0049] This allows to independently adjust the advancement speed vi of the upper elastic belt 8 and the advancement speed V2 of the lower elastic belt 9.

[0050] Therefore, such configuration allows the elastic belts 8, 9 to advance with the same advancement speed vi, V2 regardless of the elongation of each single belt 8, 9 over time so as to keep the interposed laminar products perfectly flat, stretched and free from creases and unevenness during their advancement.

[0051] The advantages listed above cannot be achieved by a staking machine of the prior art, shown by way of example in FIG. 1 and having a single motor-driven system.

[0052] In one embodiment, each electric motor 14, 15 is coupled to a respective end roller 10, 11; 12, 13 by means of a respective gearmotor 16, 17, preferably of the directly-driven type.

[0053] Preferably, the first electric motor 14 of the upper elastic belt 8 is coupled to the upper end roller 11 of the outlet area 4 for the outlet of the processed laminar products.

[0054] Similarly, the second electric motor 15 of the lower elastic belt 9 is coupled to the lower end roller 13 of the outlet area 4 for the outlet of the processed laminar products, as shown in FIG. 2 and 4.

[0055] Advantageously, the machine 1 comprises electronic control means 18 connected to the advancement means 5 for automatically varying the advancement speed vi, V2 of the elastic belts 8, 9 and therefore of the laminar products.

[0056] In one embodiment, the electronic control means 18 comprise a pair of electric sensors, not shown in the figures, adapted to respectively detect the rotation speed of an upper end roller 10, 11 and of a lower end roller 12, 13 and configured to generate first Ei and second electrical signals E2.

[0057] Advantageously, such pair of electric sensors comprises an upper sensor and a lower sensor respectively associated with an upper idle end roller 10 and a lower idle end roller 12.

[0058] As better shown in FIG. 5, the electronic control means 18 comprise an encoder 19, 20 associated with a respective gearmotor 16, 17 and configured to generate third positioning electrical signals E3, E4.

[0059] Therefore, the electronic control means 18 allow to measure the advancement speed vi, V2 of the elastic belts 8, 9 to automatically vary the rotation speed of the motors 14, 15 and of the respective rollers 11 , 13 and correct any advancement speed difference vi - V2 of the elastic belts 8, 9 increasing the speed of the slower roller 11 , 13 alone.

[0060] As a matter of fact, the staking machine 1 according to the invention, comprises a microcontrolled electronic unit on which there is installed a computer program configured to receive the electrical signals E1, E2, E3, E4 and process them to automatically adjust the advancement speed vi, V2 and keep them constantly equal to reference advancement values vn, vr2 that are preset by an operator on an interface I of the microcontrolled electronic unit.

[0061] In one embodiment, the electronic control means 18 may comprise a first inverter 21 and a second inverter 22 which are operatively connected to the microcontrolled electronic unit and adapted to respectively feed the first 14 and the second electric motor 15.

[0062] Suitably, with the first electric motor 14 and with the second electric motor 15 there are associated respective idle leather-detachment rotary brushes 23, 24 by means of respective toothed belts 25, 26.

[0063] In particular, each toothed belt 25, 26 comprises a respective belt tensioning device 27, 28.

[0064] Thus, each brush 23, 24 allows the detachment of the laminar product exiting from the outlet area 4 of the staking machine 1 which through electrostatic current or due to the adhesion caused by the friction between the laminar product and a respective belt 8, 9 tend to adhere to these latter.

[0065] Furthermore, the system formed by the toothed belts 25, 26 and the respective belt tensioning devices 27, 28 is a silent system which does not require lubrification, maintenance and cleaning.

[0066] Such advantage cannot be achieved by a staking machine of the prior art, shown by way of example in FIGS. 1 and 3, and having motor-driven leather-detachment brushes due to pinions and chains connecting the respective end roller to the respective brush.

[0067] In the light of the foregoing description, it is apparent that the staking machine 1 according to the invention achieves the pre-established objects and in particular it allows an effective and optimum adjustment of the advancement speed of both elastic belts automatically and adapting them to the processing needs of the products to be processed, so as to avoid processing creases and defects.

[0068] The staking machine according to the invention is susceptible to numerous modifications and variants all falling within the inventive concept outlined in the attached claims.

[0069] Even though the staking machine has been described with reference to the attached figures, the reference numbers utilised in the description andin the claims are meant for improving the intelligibility of the invention and thus do not limit the claimed scope of protection in any manner whatsoever.

[0070] Throughout the description, reference to “one embodiment” or “the embodiment” or “some embodiments” indicate that a particular feature, structure or element described is comprised in at least one embodiment of the present invention.

[0071] Furthermore, the particular features, structures or elements may be combined in any appropriate fashion in one or more embodiments.Industrial applicability

[0072] The present invention is applicable at industrial level because it can be manufactured on industrial scale by industries belonging to the leather and leather goods processing tanning industry.

Claims

CLAIMS1. An improved staking machine (1) for softening and stretching flexible laminar products, such as industrial leathers and the like which have opposite faces, the machine comprising: at least one pair of beating plates (6, 7) facing each other and configured to act on the opposite faces of the laminar products; motorized advancement means (5) for conveying the products along a predetermined longitudinal direction (L) and comprising at least one upper elastic belt (8) and at least one lower elastic belt (9) facing each other; wherein said elastic belts (8, 9) have an annular extension and are wound respectively on at least one pair of upper end rollers (10, 11) and one pair of lower end rollers (12, 13); characterised in that said advancement means (5) comprise a first (14) and a second electric motor (15) respectively coupled to an upper end roller (10, 11) and a lower end roller (12, 13), to allow said elastic belts (8, 9) to advance at the same advancement speed (vi, V2) regardless of the elongation of each individual belt over time and to keep the interposed laminar products perfectly flat, stretched and free from creases and unevenness during advancement thereof.

2. Machine as claimed in claim 1 , characterised in that each of said electric motors (14, 15) is coupled to a respective end roller (10, 11 ; 12, 13) by means of a respective direct-drive gearmotor (16, 17).

3. Machine as claimed in claim 1 , characterised in that it comprises electronic control means (18) connected to said advancement means (5) to vary the advancement speed (vi, V2) of said elastic belts (8, 9).

4. Machine as claimed in claim 3, characterised in that said electronic control means (18) comprise a pair of electric sensors adapted to respectively detect the rotation speed of an upper end roller (10, 11) and of a lower end roller (12, 13) and configured to generate first and second electrical signals (Ei, E2).

5. Machine as claimed in claim 4, characterised in that said pair of electric sensors comprises an upper sensor and a lower sensor which are respectively associated with an upper idle end roller (10) and with a lower idle end roller (12).

6. Machine as claimed in claim 2 and 3, characterised in that said electronic control means (18) comprise an encoder (19, 20) associated with a respective gearmotor (16, 17) configured to generate third electrical position signals (E3, E4).

7. Machine as claimed in claim 4 and 6, characterised in that it comprises a microcontrolled electronic unit on which there is installed a computer program that is configured to receive said electrical signals (E1-E4) and process them to automatically adjust said advancement speeds (vi, V2) and keep them constantly equal to reference advancement speed values (vn, vr2) preset by an operator on an interface (I) of said microcontrolled electronic unit.

8. Machine as claimed in claim 1 , characterised in that it comprises an inlet area (3) for the products to be treated and an outlet area (4) for the treated products, said first (14) and second electric motor (15) being coupled to the respective end rollers (11 , 13) of said outlet area (4).

9. Machine as claimed in claim 1 , characterised in that a respective leather detaching idle brush (23, 24) is coupled to said first (14) and second electric motor (15) by means of a respective toothed belt (25, 26).

10. Machine as claimed in claim 9, characterised in that each toothed belt (25, 26) comprises a respective belt tensioning device (27, 28).

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