WO2019077446A1

WO2019077446A1 - Frame with rotating baskets for galvanization

Info

Publication number: WO2019077446A1
Application number: PCT/IB2018/057877
Authority: WO
Inventors: Adamo BERSAGLIERE
Original assignee: Me.Ga. - S.R.L.
Priority date: 2017-10-18
Filing date: 2018-10-11
Publication date: 2019-04-25
Also published as: IT201700117705A1; EP3697945A1

Abstract

Frame with rotating baskets for galvanic treatments, provided with plates (13-13'), each of which irreversibly fixed between two uprights (11), fixed and connected by means of gears (14-14') provided with a central metal plate (15) with a pair of protruding pins (16-16') adapted to be engaged with a corresponding pair of coupling holes (26-26') placed on a side cap (22-22') of a basket (20); said basket (20) having cylindrical shape and being adapted to contain said predetermined amount of metal objects to be galvanized, constituted by a side cylindrical surface (21) of metal mesh and by a pair of side caps (22 -22" ) placed at the bases of said cylinder; said gears (14- 14') rotating in a synchronized manner in order to cause the controlled rotation of said basket (20) and allow a perfect and uniform zinc-coating treatment over all the surfaces of all the contained objects; said basket (20) being provided with at least one of said side caps (22-22') reversibly openable in order to allow, once the galvanic process has ended and said basket (20) is disconnected from the relative gears (14- 14'), gently unloading said now-galvanized metal objects, by means of a simple lateral tilt of said basket (20), making said objects slide outward.

Description

"Frame with rotating baskets for galvanization"

Description Field of the art

The present invention operates in the field of surface treatments for metal objects, in particular of zinc-coating obtained by means of immersion of the objects to be treated in an electrolyte solution. Still more in detail, the present invention has its greatest application in the process of zinc-coating small-size objects currently worked with the rotary barrel technique and/or frame technique based on their fragility.

Prior art

Zinc-coating is the process with which a zinc coating is applied on a metal manufactured item, generally made of steel, alloy or zamak etc. in order to protect it from corrosion. Indeed the zinc-coating limits the formation of electrolytic micro-cells with anode action in the grain boundaries. By grain boundaries it is intended the interface between two grains, or crystals, of a metal material or any other polycrystalline material. Zinc-coating is only one of the numerous types of galvanic treatments that can be carried out on metal objects, regarding which the present invention can have application.

Among the various galvanization techniques, one of the most widespread is the so-called "rotary barrel" technique, typically used for treating objects of small size. It consists of filling a barrel with polygonal section (hexagonal, heptagonal or octagonal section) with all the objects to be treated and the immersion of the latter in the electrolyte solution where the galvanization process takes place. Said barrel is mounted on a rotatable support, which maintains it under constant rotation in order to allow the uniformity of the treatment over all the objects and over all the surfaces of the latter. Presently, the material constituting the barrel is a plastic material and at least two knockers, provided with a metal head, are placed therein with the function of applying the electrolytic charge to the particular items to be treated and thus allow the galvanic deposition.

Several international patents have as object that of improving the quality of the pieces resulting from this type of processes, such as the patent SI23452 with title "Process of electrolytic zincing with increased anticorrosive protection". This refers to a process of electrolytic zinc -coating, stratified passivation and subsequent treatment for increasing the anti-corrosive protection. Such process respectively comprises the preliminary cleaning of the pieces, the galvanization and the final treatment that provides for a plurality of immersions in a solution of water, silicates and polyurethane.

The patent just described, like the other currently existing patents, does not effectively resolve the problem of the impacts that the small pieces to be treated sustain during processing. A high percentage of processed objects must in fact be discarded at the end of the treatment since the sustained impacts have irreversibly damaged them. Such impacts are due firstly to the rotation of the barrel which, having polygonal shape, does not "accompany" the objects in the rotation but rather overturns them; secondly, during the rotation, the two knockers inside the barrel repeatedly impact against the objects contained therein and, thirdly, the unloading of the barrel at the end of the industrial process occurs by means of opening one of its long sides and overturning the barrel in order to make ail the pieces fall within a hopper. Since said objects to be processed are commonly made of a soft metal, they are fairly easily ruined and the industrial process to which they are subjected does not have any expedient for preventing their premature wear.

Such a serious drawback of the industrial processes used today ensures that most of the small- size material is worked with the "frame" mode due to the fragility of the material or to the shape of the pieces or to the narrow geometric tolerances. The "frame" processing requires a decidedly longer preparation time in order to arrange every single piece on a suitable support.

A first object of the present invention is therefore that of allowing the "rotary barrel" processing by means of the innovative basket described hereinbelow, as well as the processing of a considerable quantity of metal objects up to now treated with "frame" technology, increasing the productivity and the effectiveness of the industrial plant,

A second object of the present invention is also that of preventing all the trauma that the pieces to be treated sustain during processing, thus decreasing the discards and further increasing the productivity of the plant.

Description of the invention

According to the present invention, a frame is made that is provided with at least one, preferably a plurality of rotating and removable baskets for carrying out the electrolytic zinc- coating, effectively resolving the abovementioned problems,

Due to the system of the present invention, without any lengthening of the processing times, a considerable reduction of the discards is attained, considerably increasing the productivity of the industrial plant.

The frame used is constituted by a metal tube structure coated with an insulator material, for example any one elastomeric plastic polymer that prevents the deposition of the galvanic solution also on the metal of the frame. The use provides for the immersion, for a predetermined amount of time, in an acidic or alkaline electrolyte solution in which the zinc or other material is situated, chemically dissolved. During the immersion, it is essential to move the metal objects to be treated in order to ensure that the deposition of the material dissolved in the galvanic solution is uniform over ail the surfaces.

Said frame is constituted by uprights, upper crossbars and lower crossbars, which define a framework or a parallelepiped. Advantageously this can be provided, inferiorly, with at least one wheel, a pair of wheels, or a plurality of wheels which facilitate the movement thereof within the plant.

Between one upright and the next, at the short sides of said frame, at least one pair of plates is arranged, preferably a plurality of pairs of plates. The latter are irremovable and are advantageously made of the same metal material as said frame and coated with the same insulator material that coats said frame.

The plates are stably and removably connected with a corresponding pair of gears placed on the inner side of said plates, i.e. that directed towards the interior of the frame. Such connection occurs by means of suitable seats provided with bushes or ball bearings.

At the center of said gears, a central metal plate is advantageously present, provided with at least one pair of pins always protruding towards the interior of the frame. Such pins are adapted to be engaged, in a stable and reversible manner, with a corresponding pair of coupling holes placed on the side caps of a basket.

Said basket is the true heart of the present invention. It is constituted by a cylinder adapted to contain said metal objects to be treated, it has a diameter comprised between 80 mm and 500 mm, preferably 200 mm and length comprised between 400 mm and 3000 mm, preferably 1000 mm.

Advantageously, at least one of the side circular- caps of said basket, which constitute the circular bases of the cylinder, is reversibiy openabie in order to allow the loading and unloading of the objects to be treated and those already treated, by means of the simple lateral tilt of the basket. In this manner, the pouring of the objects occurs in a gentle manner and without trauma for the treated objects, considerably reducing the damage of the latter and consequently the discards. This characteristic resolves the problem of trauma sustained by the metal objects at the time of basket unloading, as the latter occurred by overturning and fall of the objects into a hopper.

At least one pair of said gears is connected to a toothed wheel of a common motor. Once the motor is actuated, advantageously, it transmits the motion to said pair of gears, causing the controlled rotation of all the baskets provided with the frame. In the case of a configuration with multiple baskets, in fact, the gears, arranged one on top of the other, will be suitably- positioned for transmitting the motion to each other.

Once all the baskets to be mounted on the frame are loaded and the latter are hooked to the relative gears, the frame is ready to be immersed in the electrolyte solution.

The gears confer, advantageously, rotary movement to the baskets, which gently rotate and due to their cylindrical shape accompany the metal objects to be treated during rotation, without overturning them as occurred for the rotary barrels in use up to now. Advantageously, for each basket, also only one gear can be arranged, while on the opposite side of the frame, at the metal plate, a simple rotation pin is present.

Another advantageous characteristic is the constituent material of the baskets, which have the side cylindrical surface made of metal mesh. Advantageously, this allows the passage of a suitable electric current that is uniformly distributed for the deposition of the zinc, or of any other material dissolved in the electrolyte solution, on the metal surfaces and, simultaneously, avoids the presence of internal knockers which can damage the objects. In some preferred embodiments, the baskets can be internally provided with at least one diametrical longitudinal separator, constituted by a partition, it too made of metal mesh, which divides the inner volume of the cylinder into two longitudinal sectors. Also smaller longitudinal separators can be provided for, which further divide the volume into two other compartments that are equal to each other or which even have different volumes.

In addition, there can also be transverse divisions of the inner volume of the baskets. This advantageously allows the simultaneous treatment of different loads of different metal objects, without these being mixed.

The coupling device that serves for the division into compartments of the baskets can be constituted, merely by way of a non-limiting example, by a longitudinal rail constituted by a metal C- shaped element within which the separator is inserted in a stable and reversible manner.

Advantageously, a further embodiment of the present frame provides for at least one additional crossbar, fixed or movable, constituted by a metal tubular element coated with any one elastomeric plastic polymer adapted to prevent the deposition of zinc, or of other material, on the external surface thereof, provided with a plurality of hooks, adapted to protrude towards the exterior of said frame in order to allow the stable and reversible engagement with a corresponding plurality of metal objects to be treated.

The advantages offered by the present invention are evident in light of the description set forth up to now and will be even clearer due to the enclosed figures and the relative detailed description. Description of the figures

The invention will be described hereinbelow in at least one preferred embodiment by way of a non-limiting example with the aid of the enclosed figures, in which:

- FIGURE 1 shows a basket 20 according to the present invention in which the following are indicated: the side cylindrical surface 21 in metal mesh and the two caps 22- 22^* which constitute the bases of the cylinder. At the latter, we see the two coupling holes 26-26^" which allow the connection with the frame represented in the subsequent figures.

- FIGURE 2 illustrates a possible configuration of the basket 20 with a diametrical longitudinal separator 23 and a smaller longitudinal separator 24. The connection of the separators with each other and with the side cylindrical surface 21 is made possible by the arrangement of a plurality of coupling devices 25 constituted by metal C-shaped elements. The area inside the basket 20 is thus divided into three conipartments 29-29'-29" .

-- FIGURE 3 shows a perspective view of a frame 10 on which four baskets 20 are mounted. We see the four uprights 11 of the frame, the four upper crossbars 12 and the four lower crossbars 12" which give stability to the structure. On the short sides of the parallelepiped formed by said frame 10, we see the plates 13 at which the gears 14-14' are fixed which are reversibly connected with said baskets 20 at the respective caps 22-22'.

- FIGURE 4 shows a perspective view of an embodiment of the present invention in which said frame 10 is provided with a plurality of additional crossbars 18 provided with hooks 19 for the galvanization of metal objects, using the classic "frame" technique.

-- FIGURE 5 shows a perspective view that illustrates more in detail the reversible coupling between a basket 20 and the plates 13 of the frame 10. At the internal surface of the gear 14', a metal plate 15 is placed that is provided with a pair of protruding pins 16-16' adapted to be engaged with the corresponding coupling holes 26-26^" placed on the caps 22-22' of the basket 20.

Detailed description of the invention The present invention will now be illustrated as merely exemplifying but non-limiting and non-binding, with reference to the figures which illustrate several embodiments relative to the present inventive concept.

With reference to FIG. 3, a preferred version of the present invention is shown that is adapted to allow the zinc -coating of the contents of four baskets 20 by means of the same frame 10, hence in a simultaneous manner.

The frame 10 is constituted by four uprights 1 1 , four upper crossbar's 12 and four lower crossbars 12' which define a parallelepiped. The constituent material is any one metal or metal alloy, coated with any one insulator, for example an elastomeric plastic polymer which prevents the deposition of the zinc also on the metal structure of said frame 10.

Between the pairs of uprights 11 which define the short vertical sides of the parallelepiped, four rows of plates 13-13' are arranged, fixed to the frame 10 in an irremovable manner. Such plates are made of the same metal as the frame 10 and are coated with the same insulator material. On the inner side 13.b of said plates 13-13', these are connected with corresponding gears 14-14' by means of a suitably-configured seat, with ball bearings or bushes, which allows the rotation of said gears 14-14'. It is obvious that in the configuration of the frame 10 having a plurality of baskets 20, like that described in detail herein, the gears 14-14' are interconnected with each other such that the movement of only one pair of gears 14-14' is automatically also transferred to all the other gear's 14-14' . The motion is started by a common motor, provided with a toothed wheel connected to a pair of said gears 14-14'.

The baskets 20 are actually containers, within which the metal objects to be galvanized are loaded. Such metal objects are constituted by cylinders with diameter equal to 200 mm and length equal to 1000 mm. Possibly, as FIG. 2 shows, the inner volume of said baskets 20 can be divided into a plurality of compartments 29~29'-29" by means of partitions constrained, in a stable but reversible manner, to the internal surface of the basket 20 by means of common coupling devices 25 constituted, merely by way of example, by C- shaped metal rails. The partitions can be constituted by larger diametrical longitudinal separators 23, which divide the basket 20 into two equivalent compartments, passing through the center of the cylinder, or smaller longitudinal separators 24, which are connected to the internal surface of the basket 20 and to the center of the diametrical longitudinal separator 23. Other possible compartment forms of the basket 20 load provide for arranging transverse separators within the cylinder.

Said baskets 20 have, at the bases, caps 22-22', regarding which at least one is openable in order to allow the loading of the material to be galvanized and the unloading at the end of the operations. Due to the opening at at least one of the caps 22-22', the loading and unloading of the objects occurs gently and without trauma, by means of the simple and slight tilt of the basket 20, reducing the discards and hence the economic loss.

The stable and reversible connection between said baskets 20 and said gears 14- 14' occurs due to the arrangement of a pair of coupling holes 26-26' at the caps 22-22' of the baskets 20 and of a pair of protruding pins 16-16' on a metal plate 15, preferably with rectangular shape, placed at the center of said gears 14- 14', on the side directed towards the interior of the frame 10.

One of the most important and advantageous novelties of the present invention lies in the constituent material of the baskets 20 and of the possible internal separators 23-24. These are constituted by a common metal mesh which allows avoiding the presence of knockers within the basket, and hence preventing possible damage to the objects due to the movement of the same.

With reference to FIG. 4, a second preferred embodiment of the present invention is shown. In addition to all the components described above, the frame 10 of this further version is provided with a plurality of additional crossbars 18, made of and coated with the same materials as the frame 10, each of which provided with a plurality of hooks 19 which protrude outside in order to allow the stable and reversible engagement with a corresponding plurality of metal objects to be galvanized. Possibly and preferably, said additional crossbars 18 are reversibly removable from the frame 10.

In this manner, by using a single frame 10 and a single process of immersion in the electrolyte solution, it is possible to uniformly galvanize without trauma both the small metal objects that are loaded in the baskets 20, and the larger- size objects, which cannot be galvanized in the baskets 20 but which require the classic "frame" zinc-coating treatment. Finally, it is clear that modifications, additions or variations can be made to the invention described up to now that are clear for a man skilled in the art, without departing from the protective scope that is provided with the enclosed claims.

Claims

1. Frame (10) with rotating baskets for carrying out the galvanization of common metal objects, adapted to allow the immersion of a predetermined amount of said metal objects, for a predetermined amount of time, in an acidic or alkaline electrolyte solution, in which there is zinc or any other material adapted to obtain a galvanization treatment, in solution, so as to obtain a galvanization treatment, preferably zinc-coating, over the entire surface of said metal objects and presen'e said metal objects from oxidation; said frame (10) consisting of a metal tubular structure coated with any one insulator, such as an elastomeric plastic polymer, so as to shield the underlying metal structure and prevent the deposition of said material in solution within said electrolyte solution on the same surface of said frame ( 10), said frame (10) consisting of a three-dimensional structure, preferably parallelepiped defined, by way of non-limiting example, by at least four uprights ( 11), at least four upper crossbars (12) and at least four lower crossbars (12'); said frame (10) being characterized in that it is provided with at least one pair of plates (13- 13'), each of which stably and irreversibly fixed between two uprights (11) of said frame (10), also made of the same metal material as said frame (10) and coated with the same elastomeric plastic polymer with which said frame (10) is coated; said plates ( ISIS ' ) being provided with an outer face (13. a) and an inner face (13. b) and being fixed and stably connected, by dedicated seats provided with ball bearings or bushes, with a corresponding pair of gears (14- 14') placed on the inner side ( 13.b) of said plates (ISI S'); said gears (14-14') being provided with a central metal plate (15), preferably rectangular in shape and provided with at least one pair of protruding pins ( 16-16') adapted to be engaged, in a stable and reversible manner, with a corresponding pair of coupling holes (26-26') respectively placed on the side caps (22-22') of a basket (20); said basket (20) being cylindrical in shape and being adapted to contain said predetermined amount of metal objects to be treated; said basket (20) consisting of a side cylindrical surface (21) made with a common metal mesh and a pair of side circular caps (22-22' ) placed at the bases of said cylinder, each of which provided with a pair of coupling holes (26-26') adapted to engage, in a stable and reversible manner, with said protruding pins (16-16') of the corresponding gears ( 14-14'); said gears ( 14- 14") being in contact with a toothed wheel of a common motor, so that when said motor is actuated, it transmits the motion to said gears (14-14') which in turn start rotating in a synchronized manner to cause the controlled rotation of said basket (20), allowing a perfect and uniform galvanization of all the surfaces of the metal objects to be treated placed within said basket (20); said basket (20) being provided with at least one of said side caps (22-22') reversibly openable to allow, both at the beginning and at the end of the galvanic process, once said basket (20) has been disconnected from the relative gears (14-14'), gently unloading said now-treated metal objects contained therein, by the simple lateral tilt of said basket (20), making said now-treated metal objects slide outwards.

Frame (10) with rotating baskets for carrying out the galvanization of common metal objects, according to the preceding claim 1, characterized in that it is provided with a plurality of pairs of metal plates (13-13'), provided with the respective gear's ( 14-14') adapted to be engaged, in a stable, rotatable and reversible manner, with a corresponding plurality of baskets (20).

Frame (10) with rotating baskets for carrying out the galvanization of common metal objects, according to any one of the preceding claims 1 or 2, characterized in that at least one of said baskets (20) is provided with at least one pair of coupling devices (25) adapted to allow the stable but reversible introduction, within the volume of said basket (20), of at least one diametrical longitudinal separator (23), consisting of a partition, made of the same metal mesh as the side cylindrical surface (21) of said basket (20), adapted to divide the inner volume of said basket (20) into at least two compartments (29-29') of equal volume.

4. Frame (10) with rotating baskets for carrying out the galvanization of common metal objects, according to the preceding claim 3, characterized in that at least one of the two surfaces of said diametrical longitudinal separator (23) is provided with at least one coupling device (25) adapted to engage, in a stable and reversible manner, with at least one smaller longitudinal separator (24), consisting of a partition, made of the same metal mesh as the side cylindrical surface (21 ) of said basket (20), adapted to further divide one of said compartments (29-29') into two equal volumes or different from each other.

5. Frame (10) with rotating baskets for carrying out the galvanization of common metal objects, according to any one of the preceding claims 3 or 4, characterized in that said coupling devices (25) consist of C-shaped metal elements adapted to act as rails running lengthwise on the inner surface of said basket (20), within which one of the longitudinal edges of said longitudinal separators (23-24) is inserted.

6. Frame (10) with rotating baskets for carrying out the galvanization of common metal objects, according to any one of the preceding claims, characterized i that at least one of said baskets (20) is provided with at least one transverse separator, consisting of a partition, made of the same metal mesh as the side cylindrical surface (21 ) of said basket (20), adapted to divide the inner volume of said basket (20) into at least two compartments provided with the same volume or different volumes.

7. Frame (10) with rotating baskets for carrying out the galvanization of common metal objects, according to any one of the preceding claims, characterized in that it is provided with at least one additional crossbar- (18), consisting of a metal tubular element coated with any eiastomeric plastic polymer adapted to prevent the deposition of said material in solution within said electrolyte solution on the outer surface thereof: said additional crossbar (18) being provided with a plurality of hooks (19) adapted to protrude outwards of said frame ( 10) to allow the stable and reversible connection of a corresponding plurality of metal objects to be treated.

8. Frame (10) with rotating baskets for carrying out the galvanization of common metal objects, according to the preceding claim 7, characterized in that said additional crossbar's (18) are reversibly removable from said frame (10).

9. Frame (10) with rotating baskets for carrying out the galvanization of common metal objects, according to any one of the preceding claims, characterized in that each of said baskets (20) has a diameter comprised between 80 mm and 500 mm, preferably 200 mm and length comprised between 400 mm and 3000 mm, preferably 1000 mm.

10. Frame (10) with rotating baskets for carrying out the galvanization of common metal objects, according to any one of the preceding claims, characterized in that said pair of gears (14-14') consists of a first gear (14), connected to a first plate (13), adapted to transmit the rotation motion to the gears (14) of the adjacent baskets (20) and a rotation pin (14'), connected to a second plate (13'), adapted to facilitate the rotation motion of said basket (20) imparted by said first gear (14).

11. Frame (10) with rotating baskets for carrying out the galvanization of common metal objects, according to any one of the preceding claims, characterized in that it is inferiorly provided with at least two wheels so as to be easily moved within the galvanization plant.