Plants for immersion of bodyworks

A plant for immersion treatment of vehicle bodies may include at least one skid configured to support a body; at least one process liquid tank; a line configured to convey the at least one skid above the at least one tank; and/or a device configured to overturn and immerse, inside the at least one tank, the body on the at least one skid positioned over the at least one tank using the conveyor line. The at least one skid may include a base part and a support part. The support part may be supported rotatably on the base part using a rotatable shaft with axis arranged transverse to a direction of movement of the at least one skid on the conveyor line, so that the support part is rotatable between a first upper position and a second position for immersing the body in the at least one tank.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a national stage entry from International Application No. PCT/IB2015/059610, filed on Dec. 15, 2015, in the Receiving Office (“RO/IB”) of the World Intellectual Property Organization (“WIPO”), published as International Publication No. WO 2016/103108 A1 on Jun. 30, 2016, and claims priority under 35 U.S.C. § 119 from Italian Patent Application No. MI 2014 A 002221, filed on Dec. 23, 2014, in the Italian Patent and Trademark Office, the entire contents of all of which are incorporated herein by reference.

The present invention relates to a plant for the immersion treatment of bodywork, in particular for motor vehicles and the like.

In the art systems for the immersion treatment of vehicle bodies, in order to perform for example anti-corrosive and cataphoresis pre-treatments, are known.

These plants generally have one or more tanks containing treatment liquids and a conveyor which moves the bodies, mounted on special slides or skids, along the plant and above the tanks. Immersion systems are provided opposite the tanks and may perform for example overturning of the body inside the tank.

For the overturning operation, the body may be picked up by special means which raise it from the conveyor skid, or the skid itself may have motorized rotational shafts. Often the known immersion systems are complex, costly and bulky and require frequent maintenance.

Moreover, the final quality of the immersion treatment depends to a large extent on the method of immersion of the part to be treated. It is for example necessary to prevent air bubbles from remaining trapped during immersion or, on the other hand, the formation of liquid accumulations after re-immersion. The difficulty of achieving satisfactory results has the effect that the known devices are even more complex since they are provided, for example, with a sophisticated control system for the immersion movements, duration in the liquid and emersion. A known technique proposes, for example, skids with on-board immersion systems which require a relatively complex kinematic structure and electric motors on the skid which increase significantly the costs of said skid. Considering that along the line each body is supported by a skid, the total cost of the plant rapidly reaches a very high figure. In order to overcome this problem, movement systems which are fixed to the ground in the vicinity of the tanks, along with skids without associated immersion systems, have also been proposed. The movement systems fixed to the ground remove the body from the skid or engage the skid with the body and move it inside the tank and then deposit the body or the entire skid back on the conveyor system along the line. The immersion systems thus designed are, however, relatively complex and require sophisticated electronic management systems in order to ensure precise and reliable operation. This, however, once again increases further the costs and the complexity of the entire plant and may in any case negatively affect the reliability.

The general object of the present invention is to provide a small-size and low-cost immersion treatment plant which ensures a high degree of flexibility and optimum treatment quality.

In view of this object the idea which has occurred is to provide, according to the invention, a plant for the immersion treatment of vehicle bodies, comprising: at least one skid intended to support a body to be treated, at least one process liquid tank; a line for conveying the skid above the tank; means for overturning and immersing, inside the tank, the body on the skid which has been positioned above the tank by means of the conveyor line; the plant being characterized in that the skid comprises a base part for support and movement along the conveyor line and a part for supporting the body, the support part being supported rotatably on the base part by means of a rotatable shaft with axis arranged transverse to the direction of movement of the skid on the conveyor line so that the support part is rotatable between a first upper position and a second position for immersing the body inside the tank, the skid further comprising a toothed wheel which is connected kinematically to the shaft for controlled rotation thereof and, alongside the tank, there being provided at least one rotation actuating device which comprises a rack intended to engage said toothed wheel so as to actuate rotation of the skid support part by means of movement of the skid along a section of the conveyor line in the region of the rack.

Preferably, the skid comprises a controllable device for locking/unlocking the free rotation of the shaft which is advantageously set to the unlocking position by means of interference between its actuating shoe and at least one actuating surface present alongside the tank.

With reference to the figures,FIG. 1shows in schematic form a first example of a plant section or station for the immersion treatment of bodies, denoted generally by10and designed in accordance with the invention.

The plant10comprises at least one skid11intended to support a body12to be treated. Usually the skids will consist of a plurality circulating along the plant, each skid with a corresponding body to be treated.

The plant also comprises a conveyor line13for sequential conveying of the skids along the plant and above the tanks. The conveyor line may comprise travelways arranged parallel on the two sides of the tanks. The conveyor line may for example comprise a series of motorized rollers on which the skids rest and travel sequentially.

As can be seen inFIG. 2, the skids may comprise lateral elements or lateral runners14for resting on the conveyor line13, for example provided with motorized rollers which are arranged in two parallel rows on the two sides of the travelway and outside of the sides of the tanks of the plant.

The motorized rollers of the conveyor line may be all connected to a single motor, for example by means of a chain system, as may be easily imagined by the person skilled in the art.

Different sections of the conveyor system may also be motorized separately in order to obtain asynchronous conveying of the skids which may thus be moved at different speeds and/or stopped along the various sections.

The plant10also comprises at least one known process liquid tank15inside which the body must be immersed, for example for an anti-corrosive and cataphoresis pre-treatment. Below reference will be made to a tank, but it is understood that the tanks may consist of a plurality along the plant, also depending on the number and type of treatments required, as will be evident to the person skilled in the art.

The skid comprises advantageously a base part16traveling along the conveyor line and a part17for supporting the body, which is rotatable about a transverse axis18of a rotatable shaft19supported by the base part.

Advantageously, as can be clearly seen again inFIG. 2, the base frame of the skid may be H-shaped in plan view, with the sides of the H which are formed by the elements or runners14and a central crosspiece which connects together these elements or runners14and which comprises or is formed by the rotatable shaft19and its associated elements20for mounting on the frame. Among other things, this shape facilitates the rotation of the body about the axis18.

Advantageously, the frame has a transverse dimension such that the runners are situated outside the tanks.

As can be clearly seen inFIG. 1, the supporting or upper part of the skid may comprise support elements which are advantageously V-shaped and which extend from the rotatable shaft and are directed upwards in the normal conveying position shown inFIG. 1, for supporting and locking in position the body using known fixing means, if necessary with a support surface21arranged in between. The skid11also comprises a rotating mechanism22operated by the shaft19for bringing the body from a normal conveying position, as shown inFIG. 1, into an overturned immersion position, shown inFIG. 4.

The rotating mechanism22comprises a toothed actuating wheel23which is kinematically connected to the shaft19, optionally by means of a transmission with a suitable gear ratio (as will become clear below) for example formed by a chain of gears24,25,26, the first one being rigidly connected to the actuating wheel23and the last one being rigidly connected to the shaft19. Advantageously, the transmission between the wheel23and the shaft19will be such that the wheel23and the shaft19rotate in the same direction and preferably with a reduction in the number of revolutions.

Considering againFIGS. 1 and 2, the plant also comprises a rotation actuating device32which is arranged alongside the tanks in every position along the plant where it is required to perform controlled rotation of the body about the axis18of a skid.

As can be clearly seen inFIGS. 1 and 2, the device32comprises a rack33arranged along the direction of movement of the skids on the conveyor line13.

The rack33will have a form suitable for engagement with the toothed wheel23in order to rotationally actuate the wheel upon travel of the wheel along the rack owing to the movement of the skid along the conveyor line.

The skid also advantageously supports a device27for locking/unlocking the free rotation of the shaft19. In particular, as can be seen more clearly inFIG. 3, this device preferably interacts with the actuating wheel23and is preferably formed by a frame28pivotably mounted on the skid at29and provided with an engaging element30and an actuating shoe31. In the rest condition, the engaging element30engages in the wheel23and the relative position on the frame of engaging element30, shoe31and pivoting mechanism are such that raising of the shoe displaces the engaging element into the disengaging position.

Advantageously, owing to the weight of the frame in the rest condition (shown in broken lines inFIG. 3) the engaging element30is therefore engaged with the wheel23, locking it. The locking action may be deactivated by raising the shoe31(as will become clear below) so as to displace the frame about the pivot pin and thus disengage the engaging element30from the wheel23(as shown in continuous lines inFIG. 3). Usually, as will become clear from below, the shoe will be moved by an actuating surface alongside the tank. In particular, an actuating surface may be associated with the device32for actuating rotation of the skid.

Advantageously, as shown in the figures, the rack may be a roller rack and the wheel23may be a wheel which is correspondingly lobed so as to engage sequentially with its lobes between the rollers. This ensures safe, reliable and relatively silent engagement.

Moreover, the rollers may form the said surface for actuation of the shoe31into the raised position. Alternatively, an independent shoe actuating surface may be provided parallel to and alongside the rack.

Advantageously, the rack may be adjustable position-wise along its longitudinal extension, for example by means of a screw adjustment system34.

Moreover, again advantageously, the actuating device32may be movable controllably between the raised or operative position engaged in the wheel23, shown in continuous lines inFIG. 1, and a lowered or non-operative position (shown in broken lines) where the wheel may pass along the rack without engaging with it. The movement may be performed for example by means of a hinged parallelogram mechanism actuated by a motor38.

If it is required for any reason to convey a skid above a tank without performing rotation thereof it is thus sufficient to move the actuating device towards it non-operative position. For example, this may be useful in the case where there are bodies which must be treated in some tanks and bodies which must be treated in other tanks along the same conveyor line.

As can be seen inFIG. 4, in the normal condition for conveying along the line, nothing interferes with the shoe31and the skid may proceed conveying the body in the upper position, as though it were a normal rigid skid.

As can be clearly seen inFIG. 5, when the skid reaches an actuating device32, the skid locking/release device is actuated so as to free rotation of the shaft at the same time as engagement of the wheel with the rack in order to cause rotation of the body.

Release of the wheel and engagement of the rack are advantageously synchronized so as to be simultaneous, so that the shaft19is never idle, so as to avoid uncontrolled rotations, and ensure, on the other hand, that no jamming occurs. The position of the rack may be adjusted for this purpose.

The length of the rack may be established so as to produce a half rotation of the shaft or a complete rotation, or any angle of rotation which is desired.

In particular, at the start of a long tank a rack having a length such as to produce a half rotation of the shaft may be provided, so as to overturn completely the body and immerse it completely inside the tank. The skid may then proceed along the tank with the body immersed.

At the end of the tank a second rack may be provided, said rack having a length such as to produce another half rotation of the shaft so as to completely raise the body into the normal forward conveying position.

Alternatively, for example in the case of short tanks, a single rack may be designed with a length such as to cause the body to perform a full turn during the forward movement of the skid.

If necessary, the skid may also be stopped when the body is fully immersed, such as to cause it to remain in the liquid for the entire duration needed for the particular treatment.

It is also possible to consider causing the body to perform several immersion and emersion rotations, by means of a suitable longer rack or several racks in sequence, or cause only partial overturning operations, for example in order to keep the immersed body inclined, so as to allow the evacuation of air bubbles.

Advantageously, additional motorized driving means35(for example motorized drive rollers) may be provided, these being arranged so as to engage the skid when the rack is engaged with the wheel, so as to produce an additional driving power during the force for rotation of the body. For example, motorized rollers35may be arranged so as to rest on top of one of the runners14of the skid, formed with a suitable upper surface. The roller35may advantageously rest on the runner on the rack side so as to avoid possible raising of the runner owing to the force for rotation of the body imparted by the rack on the actuating wheel.

At this point it is clear how it is possible, simply by suitably actuating the conveyor line and any drive rollers35, to overturn a body with a predefined and also complex movement range and speed.

FIG. 6shows a possible variant of the plant according to the invention, where (advantageously in a position along the tank downstream of an actuating device32) a device36is provided for unlocking rotation of the shaft19, but not for engaging the rotational wheel23.

Preferably, this device is formed with a structure similar to that of the actuating device36, but the rack is replaced by an actuating surface37configured for actuation of the device27in order to unlock rotation. In particular, the surface37may comprise an initial section which is inclined upwards, a horizontal central section and an end section inclined downwards so as to move the shoe31into the unlocking position.

This device36may also advantageously perform a controlled vertical movement so as to move between an operative position (shown inFIG. 6) and a non-operative position where it does not interfere with the shoe31. In this way, when release is not required (for example in the case of a skid which must only pass over the tank) it is sufficient to displace the device into its non-operative position. Obviously, for safety reasons, the device36should perform release only when the body is already in its fully overturned position, so that the body may in this case be hanging, but may not produce a further uncontrolled rotation downwards. Advantageously a device for controlled pivoting of the body may be combined with the rotation unlocking device36.

FIGS. 7 and 8show an advantageous embodiment of such a device, denoted generally by40.

The device40is preferably arranged on the side of the tank opposite to the side where the unlocking device36is located and comprises a guiding and pivoting channel41which is arranged along the tank and inside which a carriage42rigidly connected to the shaft19enters and travels.

Preferably the carriage42has wheels43which travel along opposite walls of the channel41and are arranged off-centre with respect to the axis of the shaft19so as to provide an advantageous rotational arm of the shaft. The channel is formed with a desired winding progression along the tank such that, upon displacement of the skid along the tank, the carriage42causes corresponding pivoting rotations of the shaft and therefore pivoting movements of the body.

Obviously, the length and position of the channel must coincide with at least the central section of the surface37of the unlocking device36so that the pivoting movement of the carriage42takes place with the shaft19unlocked.

Additional driving means35(for example motorized drive rollers) may be provided also along the section for movement of the skid with pivoting of the body, in the case where the pivoting movement requires a greater thrust than that which can be transmitted to the skid by the conveyor line13.

As can be seen in the cross-section ofFIG. 8, advantageously the guide channel41(which is for example C-shaped) is movable between an operative position, where it may receive the carriage42, and a non-operative position, where the carriage may pass by without interfering with the channel. For example, for this movement, the guide channel may be mounted on a overturning frame50which can be inclined about an axis51by means of actuating system52arranged between the operative position (shown in continuous lines) and the non-operative position (shown in broken lines).

In this way, when pivoting of a passing body is not required, the channel may be displaced into the non-operative position. This is necessary for example when the corresponding unlocking device36is in its non-operative position.

At this point it is clear to the person skilled in the art how it is possible to combine the various parts of the plant according to the invention in order to obtain desired progressions of the bodies along the line, with great ease and flexibility.

FIG. 9shows in schematic form an example of a possible configuration of a plant10according to the invention.

In this embodiment, a first rotation actuating device32, a second unlocking device36with the associated controlled pivoting device40and a second rotation actuating device32are arranged in sequence at a suitable distance along a long tank15.

In this way, a skid11upon reaching the tank is controlled by the first device32so as to overturn the body inside the tank and immerse it in the treatment liquid, the body is then pivoted along a predefined path by the guide41of the pivoting device41and, finally, it is raised back into its normal conveying position by the second device32so as to continue its movement along the plant.

At this point it is clear how the predefined objects have been achieved.

It can be clearly seen from the figures that the treatment tank may be also only slightly greater than the size of the bodies to be treated, laterally requiring only a small amount of play between walls of the tank and side walls of the body and at the front and the rear only space to allow the movement for overturning the body and, if necessary, the displacement movement with the body immersed. The quantity of treatment liquid may therefore be minimal (with a reduction for example of about 15% compared to most conventional systems). Furthermore, a plant according to the invention allows a reduction in the widthwise volume which may for example be equal to about 25% compared to plants with body immersion arms and/or elevators.

The skids for all intents and purposes constitute both the conveyor means and the body overturning means and therefore both the classic skid and the classic transportation carriage used in the prior art are eliminated.

The skids may be designed with only mechanical members (not requiring for example electrical or electronic devices) and therefore may be used for transporting bodies not only in the pre-treatment and cataphoresis plant, but also in the following drying and polymerization ovens.

Moreover, the conveyor and overturning system remains entirely outside of the vertical plane of the tank and may be easily protected against contact with the treatment liquids.

Since the conveyor system is not situated within the vertical plane of the tank, it is possible to avoid any contamination of the liquid caused by any impurities which are transported by the plant or which may fall from the conveyor system owing to wear of the moving parts.

The system is moreover very simple and has few moving parts with low production and maintenance costs.

Obviously the description above of an embodiment applying the innovative principles of the present invention is provided by way of example of these innovative principles and must therefore not be regarded as limiting the scope of the rights claimed herein.

For example, especially along the sections which do not coincide with the treatment tanks, the skid transportation system may be of any different known type. It is also possible to easily imagine how the various embodiments and devices described may be combined with each other in any number in order to perform treatments which are complex and/or with immersion of a body in successive treatment tanks.

The conveyor line may also be designed with systems different from the motorized rollers on which the skids rest and travel. For example, other systems, such as linear motors or friction rollers, etc., may be used, as may be now easily imagined by the person skilled in the art. If the engagement between skid and conveyor line allows a sufficient transfer of driving force for the overturning operations (if for example a suitably powerful chain conveyor system is used) the motorized rollers35may be more easily dispensed with.