The present invention relates to a machine for colouring miscellaneous articles of leather and leatherette.
In particular, the present invention finds application in the field of colouring of the side edge of various articles, for example small leather items such as details for bags, saddlery or edges of shoe soles, shoe uppers, for colouring briefcases, purses and wallets, watch straps and irregularly shaped objects made of leather or leatherette, and having indentations or elbows to be coloured. Generally, leather or leatherette products undergo a colouring process, and finally a drying process to fix the colour.
The machines for colouring similar articles can be in line systems, comprising consecutive processing stations, or single machines with which the operator must interact directly. Examples of such single machines are shown in documents
In other words, for the colouring of small products or details of leather or leatherette, it is preferable to use machines comprising a colouring unit mounted on a body containing a driving engine.
This kind of machinery is particularly suitable to colour both products with regular and rectilinear forms and products having particular, irregular shapes, sharp concave and/or convex bends or very small details.
The colouring unit comprises a colouring roller having a cylindrical shape, rotatable about a preferably vertical axis. The colouring roller, properly fed with liquid colour, spreads a uniform layer of dye on the article which the operator approaches.
Under the colouring roller, there is a tray for collecting the colour, fixed to the colouring unit by screws.
The colour is poured directly inside the tray and a colour transport device, such as a screw conveyor, a suction pump system connected to a diffuser nozzle or a pad (as already known in patent
A scraper or doctor blade evenly distributes the colour on the entire surface of the colouring roller to avoid excessive colour deposits in discrete points of the product.
The excess colour, which is not transferred on the product, drips from the roller and is always recovered into the tray below.
After the colouring process, it is necessary to wash thoroughly all the parts that have come into contact with the colour, so that they can be used later also with different colours and avoiding colour changes with alteration of pigmentation.
It is therefore necessary to also remove the tray from the colouring unit, empty it and wash it thoroughly.
The maintenance operation is not easy because all the screws that hold the tray must be removed, the tray containing residual colour must be transferred to washing, the liquid colour must be disposed of if it is not reusable and, finally, the tray must be thoroughly washed and dried. Therefore, before colouring can be resumed, there is a very long machine downtime.
Also, if colour cannot be reused, this must be disposed of in liquid form, resulting in a remarkable environmental impact. Solid waste is nowadays more easily disposable and treatable, while waste in liquid form cannot simply be discharged into sewers, but must be treated with special methods.
What has just been described makes clear the need to provide a machine for colouring miscellaneous articles of leather and leatherette that is able to overcome the above-described drawbacks.
The object of the present invention is to provide a machine for colouring miscellaneous articles of leather and leatherette which overcomes the drawbacks of the described prior art.
A further object of the present invention is to propose a machine for colouring miscellaneous articles of leather and leatherette which avoids long and repeated downtime.
A further object of the present invention is to present a machine for colouring miscellaneous articles of leather and leatherette which speeds up the cleaning steps following colouring and allows a quick and efficient colour change.
Lastly, an object of the present invention is to provide a machine for colouring miscellaneous articles of leather and leatherette which has a low environmental impact.
These and other objects are substantially achieved by a machine for colouring miscellaneous articles of leather and leatherette as described in one or more of the appended claims.
Further features and advantages will become clearer from the detailed description of a preferred and non-limiting embodiment of a machine for colouring miscellaneous articles of leather and leatherette according to the present invention.
This description is provided with reference to the accompanying figures, also provided only by way of a non-limiting example, wherein:
The numeral 1 globally indicates a machine for colouring miscellaneous articles of leather and leatherette.
The machine 1 for colouring miscellaneous articles of leather and leatherette comprises a colouring unit 2 and a supporting frame 3 for the colouring unit 2.
The supporting frame 3 also acts as a housing for a driving system 4, for example an engine adapted to actuate the colouring unit 2.
The colouring unit 2 comprises a colouring head 5, adapted to apply by contact a liquid layer of colour directly on the article to be treated.
Below the colouring head 5, the unit 2 comprises a tray 6 including a removable basin 8 for collecting colour within which the colour used for the colouring of the product is contained.
The basin 8 serves both to contain the colour that is to be transferred on the colouring head 5, and to collect the colour that falls from the colouring head 5 during the colouring of the article to be treated.
The colour is transferred from the basin 8 to the colouring head 5 through a device 7 for transporting and dosing the colour, which will be described later.
The colouring head 5 is a roller, rotatable about an axis of rotation 5a that coincides with its own axis of symmetry. Preferably, the rotation axis is placed vertically.
The roller 5 has a conical or frusto-conical shape. Preferably, the tip 51 or, in case of frusto-conical shape, the smaller base 52 of the roller is turned downwards. Consequently, in both cases, the larger base 53 is facing upward. An alternative form, not shown, provides the larger base 53 facing downwards and the tip 51 or, in case of frusto-conical shape, the smaller base 52 of the roller is facing upwards.
The roller 5 may have an external lateral surface 5b having different geometries.
The external lateral surface 5b is obtained by rotating a right-angled triangle about one of the cathetuses. Depending on whether the hypotenuse is rectilinear or has a concave or convex shape, it is possible to have different geometries of the external lateral surface 5b, while always maintaining the conical or frusto-conical geometry.
Specifically, the external lateral surface 5b of the roller 5 can be at least partially planar, so as to have a side profile which is at least partially rectilinear.
Alternatively, the external lateral surface 5b of the roller 5 can be at least partially curved, in particular arched, in such a way as to have a side profile which is at least partially concave or at least partially convex.
Mixed solutions are also possible, i.e. involving an external lateral surface 5b having a rectilinear, a concave and a convex portion at the same time, or any possible combination of the three, then partially rectilinear and partially concave, or partially rectilinear and partially convex or partially concave and partially convex. If the colouring head 5 has a conical or frusto-conical shape, the smaller base can have a diameter between 0.1 mm and 20 mm, preferably between 0.1 mm and 15 mm. The particular geometry of the colouring roller 5 allows it to adapt more easily to the different dimensions and geometries of the product to be coloured. Specifically, the variation of the radius in the conical or frusto-conical surface can better adapt to the curved shapes of the object to be coloured. The conical or frusto-conical shape with the tip 51 or the smaller base 52 preferably facing downwards improves the visibility of the working area L, in that the source of light that comes from above does not create shadow zones.
Advantageously, the lighting is represented by an illumination source 16 placed vertically on the working area L with a diffusion that completely surrounds the colouring roller 5. A plurality of LEDs are preferably used. The layout and the type of lighting enhance the ergonomic aspect for the operator.
The tip 51 or the smaller base 52 of the colouring roller 5 are completely contained within the tray 6 for colour collection, particularly inside the basin 8.
The tray 6 for colour collection is movable relative to the colouring head 5, in such a way as to be easily moved away from the latter in order to allow emptying.
The tray 6 can be vertically translatable or rotatable, in both cases towards or away with respect to the colouring roller 5.
In the appended figures, only the latter configuration was represented, without any intention to exclude also the first solution with a translatable tray.
As can be seen in
The side 6a around which the tray 6 is pivoted is the rear side of the tray and is adjacent to the front wall 31 of the frame 3.
The tray 6 is movable rotatably with respect to such horizontal axis 3a between a working position (
Advantageously, the tray 6 may present in the front, in the opposite position to the hinging side 6a, 6b, a spout in such a way as to create a guide to facilitate the discharge of the residual colour when the tray is in the emptying position.
The rotation of the tray and the front spout part 6b make the emptying of the colouring liquid at the end of work both quick and easy.
The colouring unit 2 comprises a basin 8, which is disposable, insertable within the tray 6.
The basin 8 is supported inside the tray 6 without particular constraints, in such a way as to be easily removed at the end of work.
The basin 8 has substantially the same internal shape of the tray 6 with which it is coupled. Preferably, the colour is physically collected inside the basin 8, and not directly in contact with the tray 6. This constitutes a significant improvement in terms of cleanliness and greater speed to carry out the washing operations at the end of the job, or to change the type of colour.
In this way, the tray 6 is not affected by the colour and remains clean, so as to avoid having to disassemble completely and to wash.
The basin 8 with the residual colour can be easily removed from the tray 6 and washed, if required, or thrown away.
Consequently, the tray 6 remains constantly fastened to the unit 2, even if the possibility to completely disassemble the colouring unit 2, including the tray 6, remains anyway.
The liquid colour is taken from the basin 8 to the colouring head or roller 5 by the mentioned device 7 for transporting and dosing.
Such a device 7 for transporting and dosing the colour comprises a colour feed channel 9 inside which the liquid colour flows.
The feed channel 9 is placed behind the roller 5, in the opposite position to the working area L at which there is contact between the roller 5 and the article to be coloured. Advantageously, the feed channel 9 comprises a first end 9a and a second end 9b, opposite to the first and positioned at the top, then close to the larger base 53 of the colouring roller 5. The feed channel 9 is disposed almost horizontally, with a slight downward inclination, so that the liquid colour coming from the first end 9a, placed higher, flows by gravity towards the second end 9b, placed lower.
Once arrived on the top 53 of the conical or frusto-conical roller 5, the colour always flows downwards by gravity. The rotation of the roller 5 around its vertical axis of rotation 5a causes the complete fouling of the entire external lateral surface 5b of the roller 5.
Advantageously, the device 7 for transporting and dosing the colour also comprises a scraper or doctor blade 10.
The doctor blade 10 is positioned below the feed channel 9 and is coupled to the colouring roller 5 so as to follow its side profile.
The doctor blade 10, in fact, serves to dose the liquid colour on the surface of the roller 5: cooperating with the rotation of the roller 5, the doctor blade 10 distributes the colour uniformly over the entire external lateral surface 5b of the colouring roller 5 and avoids localized excesses of colour.
The doctor blade 10 and the feed channel 9 are contained in the same component placed in line behind the roller 5, in the opposite position to the working area L inside which contact between the roller and the article made of leather or leatherette to be coloured occurs.
In this way there is no interference between this component and the working area L, which remains completely free to give the operator the maximum freedom of movement of the product during the colouring step.
The device 7 for transporting and dosing the colour also comprises a transport element 11 adapted to remove the colour from the basin 8 to convey it to the colour feed channel 9.
In particular, the transport element 11 is a wheel, rotatable about a horizontal axis 11a, that draws the colour from the basin 8 and brings it at the top of the colour feed channel 9, pouring it in correspondence of the first end 9a of the feed channel 9.
The transport element 11 is also placed behind the roller 5, and in particular behind the feed channel 9, so as not to hinder any operational step.
Therefore, the whole device 7 for transporting and dosing has a very compact appearance that groups together in line the feed channel 9 and the doctor blade 10 in a single component. Moreover the compactness of the transport and dosing device 7 is also given by the position of the transport element 11, symmetrical with respect to the longitudinal axis of the feed channel 9 and placed behind the latter.
Altogether, the device 7 for transporting and dosing occupies an optimal position within the colouring unit 2 relative to the working area L, placed in front of the roller, since it is placed exactly on the opposite side with respect to the axis 5a of the roller 5, in the rear part of the roller. The doctor blade 10, the feed channel 9 and the transport element 11 are in a position opposite to the contact zone between the roller 5 and the product to be coloured, so as not to hinder the movement of the product around the roller 5.
The colours used are water-based, thus very sensitive to the ambient temperature and to the degree of humidity.
To allow the use of the machine even in very hot areas, a protective screen 13 applicable to the sides of the colouring roller 5 is provided, to leave uncovered only the working area L, immediately above the tray 6, so as to form a natural upward extension.
In this way, the colour inside the basin 8 is protected from dust or any other foreign body, in addition to being less subject to evaporation phenomena. Advantageously, the protection provided by the protective screen 13 prevents the formation of a thickened colour film on the surface of the same colour within the same basin 8.
The formation of this film is very detrimental to the quality of the treatment because it changes the percentage of concentration of colour compared to water and, if crushed, can generate lumps in the colour, with consequent problems of quality and appearance of colour application on the product.
All this requires a downtime for colour cleaning.
The protective screen 13 is removable to be able to freely enter the colouring unit 2. It can be made of plastic material, preferably transparent, to be able to constantly monitor the inside of the colouring unit 2.
The protective screen 13 protects the colour avoiding unnecessary waste and limiting its evaporation so as to significantly reduce the downtime for the recovery of the liquid during processing.
During the processing step, the detail to be coloured is moved by the operator's hands and placed in front of the machine.
The height of the colouring unit 2 compared to the operator is therefore an important factor for the ergonomics of the machine.
In known machines, the colouring unit is at a fixed and invariable height. This forces the operator to find improvised solutions to bring the colouring unit 2 to its height, or vice versa.
The colouring machine 1 object of the present invention is able to solve this drawback, by providing a colouring unit 2 that can be adjusted in height.
The colouring unit 2 is slidably constrained to the supporting frame 3, to be able to be moved vertically at will, until the optimal height is reached for the operator who at that time must interact with the machine 1.
The frame 3 has, on its front wall 31, a linear guide 14 mounted in vertical position. The colouring unit 2 can slide on this guide 14, so as to regulate the height position of the unit 2 with respect to the front wall 31 of the frame 3 (
Locking systems, not illustrated, are provided, which allow to fix the colouring unit at the established height.
The colouring unit 2 is connected to the power supply engine 4 through a plurality of components 15, such as return cylinders, tensioning rollers and a drive belt, which ensure the constant contact with the same driving engine 4, at the same time allowing the vertical translation along the guide 14.
The colouring unit 2 is completely dismantled for routine maintenance and a quick wash.
The invention allows to achieve the intended purposes in addition to ensuring enormous advantages.
The basin, insertable inside the tray for colour collection, allows to keep the tray clean, so as to avoid necessarily having to disassemble and clean also the tray at each colour change. It is sufficient to remove the basin 8 and replace it with a new and clean one.
The basin can be thrown away or washed and used again.
Downtime for colour change is thus reduced simply to the time required to remove the basin and insert a clean one.
Furthermore, if not reused, the residual colour in the basin, can be left to dry and then disposed of, with or without the tray, as a solid waste.
This has a much lower environmental impact compared to the disposal of colour in liquid form, since the treatment of solid waste requires a simpler and less invasive process.
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.