EP2189554A1 - Carrying device and method of galvanising one or more workpieces - Google Patents

Abstract

Support device (1) comprises a holding unit (13) which rotates about an axis of rotation (A) which runs inclined at an acute angle (alpha ) in relation to the vertical (V). An independent claim is also included for a method for galvanizing workpieces (29) using the above support device.

Description

The present invention relates to a support device for holding one or more workpieces during plating, wherein a holding device is suspended rotatably about an axis of rotation on the support device, wherein the holding device is configured such that one or more workpieces are radially spaced from the axis of rotation, and wherein a drive for rotating the holding device about the axis of rotation is provided, and a method for galvanizing one or more workpieces.

High-quality coatings of metallic workpieces are of exceptionally high interest in many applications. For example, in the high-pressure fuel line of a modern common-rail injection system for internal combustion engines in the form of a pipe feed line is required, which has applied to the outer surface coating of the pressure accumulator serving pipe section of high quality. In addition, to allow particularly short pressure rise times and multiple injections per stroke, the inner surface of the common pipe inlet must be particularly homogeneous and smooth, in order to keep the flow resistance at the pipe inner wall as low as possible and to avoid attack points for deposits. Therefore, the inner surface must not be damaged by corrosion, which can occur when liquid can not flow out of the interior of the pipe after a galvanizing.

In addition, there are numerous other application examples such as cooking pots, in which a homogeneous and smooth surface of a metallic workpiece of importance. For the coating of metallic workpieces or workpieces with at least electrically conductive surface, the known electroplating process for the electrolytic deposition of a coating material is generally used. Often this is a zinc or zinc / nickel coating. However, any other suitable for an electrolytic deposition coating can be applied depending on the application.

In electroplating, it is common practice to perform the coating process by several immersions in different baths with different bath media, such as cleaning baths, ultrasonic baths, pickling baths, acidic or alkaline baths, degreasing baths and electroplating baths. For this purpose, it is known from the prior art to use holding frames or racks so that the workpieces can be held during the immersion operations. From the US 4,872,963 , of the US 4,233,149 or the US 4,481,098 For example, such holding frames are known.

In order to enable a removal of air bubbles, which form in the course of the dipping process on the workpiece, it is advantageous, as in the US Pat. No. 6,630,059 B1 , of the US 2006/0204668 A1 or the DE 103 09 401 A1 described to fasten the workpieces spaced apart to a horizontal shaft and to rotate the shaft during a dipping operation about the horizontal axis. The rotation after a dipping process also allows a uniform drainage of the liquids can be achieved.

A disadvantage of the in the US Pat. No. 6,630,059 B1 , of the US 2006/0204668 A1 and the DE 103 09 401 A1 described support devices is that the rotatable mounting is located at both ends of the shaft during the immersion process in the bath medium and the power supply to the workpieces is made difficult. Furthermore the resulting coating does not have the desired quality. In particular, the layer thicknesses over the entire surface of the workpiece can not be sufficiently uniform, and the roughness can be too large.

From the CH 694 643 A5 is also known to rotate workpieces during a dipping process about a vertical axis of rotation. This has the advantage that the upper storage and the power supply of the vertically arranged shaft is outside the bath medium. However, a residue-free ventilation of the workpiece as in a rotation about a horizontal axis does not take place here. In addition, there is the risk that after the immersion liquid remains inside the workpieces, so that it can come later to corrosion.

It is therefore starting from the DE 103 09 401 A1 the object of the present invention to provide a support device and a method for electroplating one or more workpieces, by which an improved coating quality and in particular a residue-free ventilation of the workpiece can be achieved.

This object is solved according to the present invention by the features of independent claims 1 and 9. Advantageous embodiments of the invention are covered in the respective dependent claims.

According to a first aspect of the present invention there is provided a support apparatus for holding one or more workpieces during plating, wherein a support means is rotatably suspended about an axis of rotation on the support apparatus, wherein the support means is configured such that one or more workpieces are radially spaced from the axis of rotation are held, and wherein a drive for rotating the Holding device is provided around the axis of rotation, characterized in that the axis of rotation is inclined at an acute angle with respect to the vertical.

In the context of this invention, the term "electroplating" refers to all process steps in electroplating. This includes not only the actual coating steps in electroplating baths, but also all immersion steps in various other baths with different bath media such as cleaning baths, ultrasonic baths, pickling baths, acidic or alkaline baths and degreasing baths. In this sense, "plating" further includes a dripping, drying or cleaning step before or after a dipping operation.

The acute angle to the vertical includes all inclination angles between a horizontal and a vertical axis of rotation, ie between 0 ° and 90 ° to the vertical except for these critical angles. An exact horizontal and an exactly vertical arrangement of the axis of rotation are thus explicitly excluded.

As a result of the inclination angle according to the invention, it is achieved that the workpieces are vented without residue by a rotation of the holding device about the axis of rotation inclined to the vertical during a step during galvanizing and the coating quality is improved by a more homogeneous layer thickness distribution. The inclination of the axis of rotation also ensures that after removing the workpieces from a galvanizing bath and a further rotation about the axis of rotation no liquid remains in the workpieces and so the risk of corrosion is reduced.

It is also advantageous over the prior art that the holding device is not completely submerged in a bath medium must be, but an upper end during a dipping process outside the bath medium can remain and thus both the drive for the rotation and the power supply is much easier.

Preferably, the acute angle between 5 ° and 45 °. It has proved to be particularly advantageous to choose an acute angle between 10 ° and 20 ° and in particular an angle of about 15 °.

In a preferred embodiment of the invention, the support device can also be designed so that the acute angle is changeable between 5 ° and 45 ° adjustable. In this way, the device can be adapted to different Werkstükke.

For the electroplating process, the surface of the workpiece to be coated must have an electrical potential difference with respect to the bath medium. This can be achieved in that the holding device is designed to be electrically conductive and in electrically conductive contact with the workpiece to be coated, so that then a voltage between the holding device together with the clamped workpieces and other electrodes of the electroplating can be applied. In order that the holding device can be used as part of the external circuit of the electroplating and thereby not coated, the holding device is preferably formed of electrically conductive material such as copper or steel and is substantially completely covered with an electrically insulating layer with the exception of the contact areas with the to be coated workpieces.

According to an advantageous embodiment of the carrying device according to the invention, this comprises an upper and a lower carrier, and the holding device comprises a support shaft with an upper and a lower end. One or more retaining struts are provided on the support shaft, which extend substantially in the radial direction to the axis of rotation of the support shaft. The support shaft is rotatably mounted with the upper end on the upper support and with the lower end on the lower support about the axis of rotation. In this case, the upper bearing of the support shaft is located during a step during electroplating outside of a bath medium, so that the drive for the rotation and the power supply to the support shaft is easily possible. In this embodiment, the holding device is particularly simple and compact.

The drive is advantageously mounted on the upper support and operatively connected to the upper end of the support shaft. In this case, the support shaft may be mounted with the lower end in a ball joint and be connected at the top with the upper end via a bolt or universal joint with a vertically rotatable connection shaft. The acute angle of inclination can be carried out particularly easily in this embodiment by a horizontal displacement of the vertically rotatable connection shaft along the upper support of the support device.

Preferably, a plurality of holding devices is provided, wherein each holding device is rotatably suspended about a rotational axis associated therewith in the carrying device and wherein the holding devices are configured such that one or more workpieces are held radially spaced from their associated axes of rotation, and wherein a drive to Rotating the holding devices is provided to their associated axes of rotation. In this case, the support shafts can each be mounted with the lower end in a ball joint and connected at the top with the upper end via a bolt or universal joint, each with a vertically rotatable drive shaft.

In this embodiment, the drive can have, for each holding device, a vertically rotatable connecting shaft which can be driven jointly via a horizontally arranged drive shaft which extends substantially along the upper carrier. In this embodiment, the capacity of the carrying device can be increased.

1. a) Befestigen der zu beschichtenden Werkstücke in einer Halteeinrichtung, die in einer Tragvorrichtung drehbar um eine Drehachse aufgehängt ist, so dass die Werkstücke radial beabstandet von der Drehachse gehalten werden und die Drehachse in einem spitzen Winkel bezüglich der Vertikalen geneigt verläuft, und
2. b) Rotieren der Halteeinrichtung um die Drehachse während eines Schrittes beim Galvanisieren.

According to another aspect of the present invention, there is provided a method of electroplating one or more workpieces, comprising the steps of:

1. a) attaching the workpieces to be coated in a holding device, which is suspended in a support device rotatably about an axis of rotation, so that the workpieces are radially spaced from the axis of rotation and the axis of rotation is inclined at an acute angle with respect to the vertical, and
2. b) rotating the retainer about the axis of rotation during a plating step.

In this method, the advantages already explained in connection with claim 1 of the present invention are achieved, namely that the workpieces are deaerated residue-free and the coating quality is improved by a more homogeneous layer thickness distribution.

Preferably, the acute angle is set in the range between 5 ° and 45 ° during the attachment step. It is particularly advantageous if, during the fastening step, the acute angle is set to a value between 10 ° and 20 °, in particular about 15 °.

In a preferred embodiment of the method according to the invention, a carrying device according to one of claims 1 to 8 is used.

• Figur 1 zeigt einen Längsschnitt der Tragvorrichtung mit den gehaltenen Werkstücken.
• Figur 2 zeigt einen Querschnitt der Halteeinrichtung senkrecht zur Drehachse samt gehaltener Werkstücke.
• Figur 3 zeigt einen Längsschnitt der Tragvorrichtung mit einer Mehrzahl von Halteeinrichtungen.

In the following, the present invention is based on the FIGS. 1 to 3 explained, which represent only a preferred embodiment of the support device according to the invention.

• FIG. 1 shows a longitudinal section of the support device with the held workpieces.
• FIG. 2 shows a cross section of the holding device perpendicular to the axis of rotation together with held workpieces.
• FIG. 3 shows a longitudinal section of the support device with a plurality of holding devices.

In the FIG. 1 and 2 Supporting device 1 shown has an outer support frame 3, which comprises an upper support 5 and a lower support 7 and side elements 9, 11. Between the upper and the lower carrier 5, 7, a holding device 13 is suspended rotatably about a rotation axis A on the support device 1, wherein the axis of rotation A is inclined at an acute angle α with respect to the vertical V. The holding device 13 has a support shaft 15 extending along the axis of rotation A, which is connected to an upper end 17 via a vertical connecting shaft 19 with the upper carrier 5. In order that the support shaft 15 can rotate about its longitudinal axis and thus about the axis of rotation A inclined at an acute angle α relative to the vertical V, the upper end 17 of the support shaft 15 is connected to the drive 21 via a pin joint 20. At the lower end 23, the support shaft 15 is pivotally and rotatably mounted in a ball joint 25 and thus connected to the lower carrier 7.

From the support shaft 15 extend radially from the axis of rotation A holding struts 27, which are adapted to clamp workpieces 29 by means of a spring tension. On the support shaft 15 are radially extending from the support shaft 15 extending plate-shaped plates 30, followed by the support struts 27 connect. The holding struts 27 have loops 31 which can generate a spring tension in the longitudinal direction of the axis of rotation A. Two holding struts 27 can each act on an upper and on a lower engagement surface of a workpiece 29 and hold the workpiece 29 by opposing spring tension. By means of this construction it is achieved that the workpieces 29 are held radially spaced from the axis of rotation A. In the FIGS. 1 and 2 It is shown how a plurality of workpieces 29 are held radially spaced from the axis of rotation A via the holding struts 27 extending radially from the axis of rotation A. In this embodiment, the workpieces 29 are essentially oriented parallel to one another on a jacket plane surrounding the support shaft 15. The workpieces 29 are shown as pipe sections with radially projecting and pierced end fittings 33. The pierced extensions 33 provide with the inner surfaces of the holes for the clamping of the workpiece 29 necessary attack surfaces on which the retaining struts 27 attack. About this attack surfaces also flows necessary for a galvanization electric power. The engagement surfaces that are in contact with the support struts 27 can not be coated because they do not come in contact with the bath medium. The engagement surfaces for attaching the workpieces 29 should therefore be relatively small and be located on a relative to the coating quality relatively insignificant part of the workpiece 29.

It can serve as attack surfaces but also the annular top and bottom cross-sectional areas at the ends of the pipe section. In this case, the support struts 27 in the form of tapered printheads with a diameter of the Pipe section superior extent selectively grip in the upper and lower pipe opening and hold the workpieces 29 each with a compressive stress from above and below. In this case, especially at the upper end of the pipe section may not be completed to allow a residual-free ventilation of the inner region of the workpiece 29. It may also be necessary that the lower tube opening is not completely closed, so that after removing the workpieces 29 from the electroplating bath 29 by a rotation of the support shaft liquid from the workpieces 29 can run completely, so it later not to corrosion inside the workpieces 29 is coming.

In principle, the workpieces 29 may have any shape suitable for being held radially spaced from the axis of rotation A. For example, the workpieces 29 may be cooking pots or other items that require a high quality plating coating.

The drive 21 comprises in this embodiment a drive motor 35, a horizontally arranged drive shaft 37 and a vertically rotatable connection shaft 19. The drive motor 35 is provided to drive the horizontal drive shaft 37 in rotation. During operation, the rotation of the horizontal drive shaft 37 is transmitted to the vertical rotatable connection shaft 19 through a gear 39 so that it rotates about a vertical axis. Thus, the support shaft 15 can rotate about its longitudinal axis and thus at an acute angle α with respect to the vertical V inclined axis of rotation A, the upper end 17 of the support shaft 15 is connected via the pin joint 20 with the vertical drive shaft 19 of the drive 4.

The acute angle of inclination α between the vertical V and the axis of rotation A can be in this preferred embodiment by horizontal displacement of the vertical drive shaft 19 together with gear 39, as indicated by the double arrow 41 set. It is therefore also conceivable that the inclination angle α is fixed. The acute angle .alpha. Can in principle encompass all inclination angles between a horizontal and a vertical axis of rotation A, but the range is limited here because of the construction. However, the exact horizontal axis and the exactly vertical axis of rotation A are explicitly excluded. Preferably, the acute angle α is set between 5 ° and 45 °. It has proved to be particularly advantageous to set an acute angle α between 10 ° and 20 ° and in particular an angle α of about 15 °.

Since the drive 21 and the upper end 17 of the support shaft 15 are outside a bath medium during galvanization, a power supply to the support shaft 15 and thus to the coating workpieces 29 is easily possible. In order for the holding device 13 to be used as part of the external electrical circuit of the electroplating plant and not itself electroplated, the holding device 13 is preferably made of electrically conductive material such as copper or steel and is substantially completely covered with an electrically insulating layer with the exception of the contact areas with the workpieces to be coated 29 and its attack surfaces.

In FIG. 3 an embodiment of the support device 1 is shown, wherein a plurality of holding devices 13 is provided in order to coat as many workpieces 29 in one step during electroplating can. In this case, each holding device 13 is rotatably suspended about its associated axis of rotation A in the support device 1 as described above. The holding devices 13 are configured such that one or more workpieces 29 are held radially spaced from their associated axes of rotation A. A drive 21 for rotating the holding devices 13 about their associated axes of rotation A is also provided.

Each holding device 13 is in this case designed as described in the preceding embodiment. In this case, the support shafts 15 are each pivotally and rotatably mounted with the lower end 23 in a ball joint 25 and thus connected to the lower carrier 7. In this embodiment, the drive 21 has, for each holding device 13, in each case a vertically rotatable connection shaft 19, which together with a horizontally arranged drive shaft 37, which extends substantially along the upper carrier 5, with the drive motor 35 or from the outside by an external motor can be driven.

Out FIG. 1 In addition, it becomes clear how the method according to the invention for galvanizing preferably proceeds. The workpieces 29 to be coated are first fixed in the holding device 13, wherein this is suspended in the carrying device 1 rotatable about the axis of rotation A. The workpieces 29 are held radially spaced from the axis of rotation A, and the axis of rotation A extends at an acute angle α with respect to the vertical V inclined. As indicated by arrow 43 in the Figures 1 and 2 is indicated, the holding device 13 is rotated about the axis of rotation A during a step in electroplating. Galvanizing encompasses all process steps in a galvanizing process. This includes not only the actual coating steps in electroplating baths, but also all immersion steps in various other baths with different bath media such as cleaning baths, ultrasonic baths, pickling baths, acidic or alkaline baths and degreasing baths. In this sense, plating further includes a dripping, drying or purging step before or after a dipping operation.

During the attachment step, the acute angle α can be set in the range between 5 ° and 45 ° by the horizontal drive shaft 19 including the gear 20 is moved horizontally. The setting of an acute angle of inclination α between 10 ° and 20 °, and in particular of 15 °, has proved to be particularly advantageous for the coating thickness distribution of the coating and the venting of the workpieces 29.

Claims (12)

Carrying device (1) for holding one or more workpieces (29) during electroplating, wherein a holding device (13) is suspended rotatably about an axis of rotation (A) on the carrying device (1), wherein the holding device (13) is designed such that a or a plurality of workpieces (29) radially spaced from the axis of rotation (A) are held, and wherein a drive (21) for rotating the holding device (13) about the axis of rotation (A) is provided,
characterized in that
the axis of rotation (A) is inclined at an acute angle (α) with respect to the vertical (V). Carrying device (1) according to one of the preceding claims, wherein the acute angle (α) is between 5 ° and 45 °. Carrying device (1) according to one of the preceding claims, wherein the acute angle (α) between 10 ° and 20 °, in particular about 15 °. Carrying device (1) according to one of the preceding claims, wherein the acute angle (α) is adjustable in the range between 5 ° and 45 °. Carrying device (1) according to one of the preceding claims, wherein the holding device (13) is formed of an electrically conductive material and is substantially completely covered with an electrically insulating layer with the exception of the contact areas with the workpieces to be coated (29). Carrying device (1) according to one of the preceding claims, wherein the carrying device (1) has an upper and a lower carrier (5, 7) and the holding device (13) has a support shaft (15) with an upper (17) and a lower end (23 ), wherein the upper end (17) of the support shaft (15) is connected to the upper support (5) and the lower end (23) of the support shaft (15) is rotatably connected to the lower support (7) about the rotation axis (A) , and wherein on the support shaft (15) one or more support struts (27) are provided, which extend substantially in the radial direction to the axis of rotation (A) of the support shaft (15). Carrying device (1) according to claim 6, wherein the drive (21) is mounted on the upper support (5) and connected to the upper end of the support shaft (15). Carrying device (1) according to one of the preceding claims, wherein a plurality of holding devices (13) is provided, wherein each holding device (13) is rotatably suspended about its associated axis of rotation (A) in the carrying device (1), and wherein the holding devices ( 13) are configured such that one or more Werkstükke (29) radially spaced from their associated axes of rotation (A) are held, and wherein a drive (21) for rotating the holding means (13) to their associated axes of rotation (A) is. Method for electroplating one or more workpieces (29), comprising the following steps: a) fixing the workpieces (29) to be coated in a holding device (13) which is suspended in a support device (1) rotatable about an axis of rotation (A), so that the workpieces (29) radially spaced from the axis of rotation (A) held be, and the axis of rotation (A) is inclined at an acute angle (α) with respect to the vertical (V), and b) rotating the holding device (13) about the axis of rotation (A) during a step in electroplating. A method according to claim 9, wherein during the fixing step, the acute angle (α) is set in the range between 5 ° and 45 °. A method according to claim 9 or 10, wherein during the fixing step, the acute angle (α) is set to a value between 5 ° and 45 °, in particular about 15 °. Method according to one of claims 9 to 11, wherein a carrying device (1) according to one of claims 1 to 8 is used.

Images