WO1991009983A1

WO1991009983A1 - Frame rod

Info

Publication number: WO1991009983A1
Application number: PCT/DE1990/000879
Authority: WO
Inventors: Günther Strecker; Gerhard Wilhelm
Original assignee: Schering Ag, Berlin Und Bergkamen
Priority date: 1989-12-21
Filing date: 1990-11-15
Publication date: 1991-07-11
Also published as: DE3942418A1

Abstract

A frame rod (2) for dip-galvanizing plate-shaped objects has holding devices (8) consisting of two clamps (10, 12) which are screwed to the frame rod (2) in such a manner that the facing legs (18, 22; 20, 24) of the two clamps form an insertion slot (26). Disks (46, 48) supported on inclined planes (38, 40) in one leg (22, 24) clamp the plate-shaped object between the disks and contact surfaces (42, 44) on the front faces of the other leg (18, 20).

Description

Rack rod

description

The invention relates to a rack rod for electroplating objects, in particular plate-shaped objects such as printed circuit boards, with holding devices fastened to the rack rod for fixing the objects to the rack rod, the holding devices each having a rolling body which is mounted on an inclined plane and can be rolled The plate-shaped object can be inserted into the holding device via an insertion slot and can be clamped between the rolling element and an opposite contact surface.

Usually, in the galvanizing of objects, in particular printed circuit boards, the objects are attached or attached to galvanizing racks in galvanic baths and immersed together with them in a galvanic bath. Power is supplied via the mounting rails, which are arranged across the treatment bath and on which the galvanizing racks are attached. The objects to be treated in the galvanic bath are attached to the lower part of the galvanizing frame, the so-called frame rod. The above-mentioned holding devices are used to fix the objects to the frame rods

REPLACEMENT LEAF provided in which the plate-shaped object can be clamped between a ball mounted on an inclined plane and an opposite contact surface.

In a known arrangement, cages are welded to the frame rod, the side walls of which define the inclined plane and the contact surface between which the clamping ball is mounted, the front of the cage having a slot for inserting the plate-shaped object into the cage.

A major disadvantage of this known construction can be seen in the fact that the cages mentioned are comparatively thick, that is to say they protrude considerably beyond the profile of the frame rod, so that the field line course is disturbed due to the large height of the known cages after the Field lines are strongly deflected, so that the desired uniform layer distribution on the plate to be galvanized cannot be achieved with the desired quality. Furthermore, in the known construction, the insertion slots are not arranged centrally with respect to the frame rod, which results in different field line configurations on the front and on the back of the circuit boards, so that the front and rear of the circuit board are coated differently, that is to say not uniformly.

In the known construction, it was also found to be disadvantageous that it is extremely inflexible in terms of subsequent necessary changes in the position of the cages on the frame rod. Finally, due to the welded construction, the precision of the known construction is also not optimal.

REPLACEMENT LEAF A further construction of a rack bar, in which the holding devices are also designed in the form of rolling bodies guided on an inclined plane and corresponding stop surfaces, is such that the rack bar has a longitudinal groove and that recesses are provided in one side wall of the longitudinal groove at predetermined intervals are formed in which the rolling body is mounted. With this construction, the problems of the strong deflection of the field lines and the different field line configurations on the front and back of the printed circuit board to be coated, which arise in connection with the first-mentioned construction, are avoided, but it also remains here however, the disadvantage of the lack of flexibility of the design when changing requests. In addition, the known construction is disadvantageous in terms of washing technology, since material can be retained in the longitudinal groove of the frame rod which is difficult to remove. Furthermore, the known construction is technically complex and therefore expensive. Furthermore, the problems with the current transfer can arise after the plate to be coated lies over its entire length on the side wall of the longitudinal groove of the rack rod and the contact pressure is thus low. Finally, it is disadvantageous that, due to the longitudinal groove and the cage construction integrated into the frame rod, the electrically conductive cross section of the frame rod is considerably reduced.

The invention is therefore based on the object of creating a rack of the type mentioned at the outset, in which the disadvantages of the known prior art are substantially avoided, the rack rod according to the invention being distinguished primarily by good electrical properties

REPLACEMENT LEAF and distinguish technical washing properties with a simple and inexpensive construction.

According to the invention, this object is essentially achieved in that the holding device is formed by two angular parts, one leg of which is screwed to the frame rod on opposite sides of the frame rod and the other legs of which are connected to one another on a side of the frame rod connecting the opposite sides taper and face each other to form said insertion slot, one of the two legs for forming the inclined plane and for receiving the rolling body between itself and the frame rod being provided on its side facing the frame rod with a correspondingly shaped recess, and the end face of the other leg facing this leg forms the abovementioned opposite contact surface.

The insertion slot is preferably arranged essentially centrally with respect to the frame rod, and the rolling body is also designed as a disk.

Although the angular parts could be L-shaped and then a pair of these angular parts define a holding device, it is provided in a preferred development of the invention that the angular parts are each designed as U-shaped clips, the base of which can be screwed onto the frame rod, wherein two opposite legs of a pair of clips each form a holding device on opposite sides of the frame rod, that is, a single pair of clips defines two holding devices.

_ERSA TZBLATT The construction according to the invention has a number of advantages over the known prior art. On the one hand, the overall height of the brackets can be kept comparatively low, as a result of which there is only a slight electrical shielding in the area of the brackets and the field line configuration is only slightly influenced. Due to the preferably central arrangement of the slot, the field line distribution on the front and rear of the circuit board is uniform, which results in the same conditions for the coating on the front and rear of the circuit board. Furthermore, since the printed circuit boards to be coated only rest in the area of the clamps on the frame rod, the clamping area is comparatively small, and due to the high contact pressure that can be achieved in this way, good contact between frame rod and printed circuit board can be assumed.

Another considerable advantage of the construction according to the invention can be seen in its high flexibility, since the angular parts or brackets need only be screwed into other screw holes on the frame rod if necessary, in individual cases changes in the arrangement should be necessary or desirable his. In addition, welding work can be dispensed with, and the frame rod as a component remains practically unchanged in the case of the construction according to the invention with the exception of the threaded bores to be formed. Due to the avoidance of welded constructions, high manufacturing precision can be achieved.

In a preferred development of the invention it is provided that in each pair of clips the two legs of the one clip are each provided with a recess and the end faces of the two legs of the other clip.

REPLACEMENT LEAF always define the opposite contact surface. With such a construction, only a single clamp of a pair of clamps has to be machined to form the recesses, while the other clamp can remain unchanged.

It is particularly preferred that the two clips of a pair of clips have essentially the same cross section, so that all clips can be produced from the same U-shaped profile material.

It is also preferably provided that the frame rod has a single, continuous threaded bore for each pair of angle parts or brackets; the only change that the rack rod thus experiences as a component is a single threaded hole for two holding devices in each case.

In a preferred development of the invention, it is provided that the longitudinal edges of the frame rod are chamfered, which on the one hand achieves a more favorable field line distribution by avoiding sharp edges and on the other hand results in a construction which is optimized in terms of washing technology, after in such a case additionally the area can be rinsed between the inner edge of the clip and the frame rod.

Further advantageous features of the invention emerge from the remaining subclaims and from the following description, in which several exemplary embodiments of the invention are explained in more detail with reference to the drawing. The drawing shows:

FIG. 1 shows a ^" partial view of a rack rod according to the invention in a side view,

REPLACEMENT LEAF FIG. 2 shows a side view in the direction of arrow II according to FIG. 1,

FIG. 3 shows a top view of the rack rod in the direction of arrow III according to FIG. 1,

Figure 4 is a plan view of an alternative embodiment of the contact surface of the bracket legs of the holding device, and

Figure 5 is a side view of an alternative embodiment of the contact surface of the bracket legs of the holding device.

First of all, reference is made to the exemplary embodiment according to FIGS. 1 to 3. The reference number 2 denotes a frame rod to which a holding device, designated overall by reference number 8, is fastened. It goes without saying that at least two holding devices 8 are generally arranged in a longitudinal direction on a rack bar 2 after each printed circuit board or the like to be held on the rack bar 2 or the like on each rack bar generally by means of two holding devices 8 is held. However, since the holding devices 8 are each constructed identically, it is sufficient for the purpose of the present description to explain only a single holding device 8 in more detail.

Each holding device 8 comprises two brackets 10, 12 which, as can be seen in particular from FIG. 3, are each substantially U-shaped in cross section and each have essentially identical dimensions. The brackets 10 and 12 each have a base 14 and ^'16, and at both ends of the base 14, 16 each comprise a right angles thereto extending leg 18,

REPLACEMENT LEAF 20 or 22, 24. The clear width between the legs 18, 20 or 22, 24 essentially corresponds to the corresponding dimension of the frame rod 2, so that the clamps 10, 12 grip the frame rod from opposite sides practically without play.

The length of the legs 18, 20, 22 and 24 is in each case the same and dimensioned such that when clips 10, 12 are mounted on the frame rod 2, the legs 18 and 22 or 20 and 24 face each other to form an insertion slot 26 which is of sufficient width has in order to receive the plate-shaped object to be treated at its edge region. It follows from the foregoing that the insertion slots 26 are arranged exactly in the center with respect to the frame rod 2.

In the rack rod 2, through-threaded bores 28 are formed at suitable positions, which run perpendicular to the longitudinal direction of the rack rod 2 and in the center and for receiving mounting screws 30, 32 on both sides, by means of which the clamps 10 and 12 are screwed to the rack rod 2 become.

As can be seen from FIGS. 1 and 3, recesses 34, 36 are formed on the inner sides of the legs 22, 24, the rear side of the recess facing the base 16, as can be seen in particular from FIG. 1, in each case as an inclined plane 38, 40 is formed, which increasingly approaches the base 16 from bottom to top. In the space zwi¬ rule the rack bar 2, the legs 22 and 24, respectively, of the rail slat fen plane 38, 40 and this opposing Anlage¬ surface 42 and ^'44, 18 and 20 of the bracket from the front side of the leg 10 is defined, a disc-shaped rolling body 46, 48 is captive and with

REPLACEMENT LEAF sufficient play freely rotatable. In order that the disks 46, 48 cannot fall out upwards in the illustration according to FIG. 1, securing pins 50 are fastened to the clamp 12, which on the one hand sufficiently close off the space accommodating the disks 46 and 48 to slide out to prevent the panes, on the other hand, not significantly impair flushing through this space. It should also be noted that the securing pins 50 are not shown in the case of the illustration according to FIG. 3 for the sake of clarity.

The edges of the frame rod 2 are beveled, as can be seen in particular from FIG. 3, the width of the bevels 6 being at least a few millimeters. The outer, longitudinal edges of the brackets 10, 12 are also clearly bevelled.

As can be seen from FIG. 1, the lower corners of the legs 18, 20, 22, 24 of the brackets 10, 12 are also chamfered in order to define insertion bevels in this way which facilitate the insertion of the plate-shaped objects to be treated into the holding devices 8. To fix the plate-shaped objects to be treated to the frame rod 2, the plate-shaped objects are inserted from below via the insertion bevels into the insertion slot 26 of the holding device 8, the disks receding upwards on the inclined plane, and the plate-shaped object is then removed with a short Pulled downwards so that the plate is clamped between the disk 46 or 48 and the opposite contact surface 42 or 44 of the clamp 10.

REPLACEMENT LEAF In the above exemplary embodiment, the system surfaces 42, 44 are designed as flat surfaces. According to FIG. 4, these contact surfaces can also be designed as a roof-shaped elevation 52, in which case there is essentially a line contact with the plate-shaped object and the contact pressure of the plate-shaped object against the clamp 10 is thus increased. In a further alternative embodiment, the contact surfaces 42 and 44 can be provided with nub-shaped elevations 54, so that in this case there is essentially point contact between the plate-shaped object and the clamp 10. Those skilled in the art are familiar with further configurations of the contact surfaces which serve to increase the contact pressure.

Instead of the disks, balls or rollers can also be used as rolling elements.

REPLACEMENT LEAF

Claims

Expectations

Rack rod for electroplating objects, in particular plate-shaped objects such as printed circuit boards, with holding devices (8) fastened to the rack rod (2) for fixing the objects to the rack rod, the holding devices (8) in each case on an inclined plane (38, 40 ) have rollably mounted rolling elements (46, 48), and the plate-shaped object can be inserted into the holding device via an insertion slot (26) and can be clamped between rolling elements (46, 48) and an opposing contact surface (42, 44), characterized in that the Holding device (8) is formed by two angle parts (10, 12), one leg (14, 16) of which is screwed to the frame rod on opposite sides of the frame bar (2) and the other legs (18, 22) and 20, 24) run towards each other on a side of the frame rod connecting the opposite sides and face each other to form the insertion slot (26) mentioned rest, one (22, 24) of the two legs (18, 22 or 20, 24) to form the inclined plane (38, 40) and to receive the disc (46, 48) between itself and the frame rod (2) is provided on its side facing the support rod with a correspondingly shaped recess (34, 36), and the end face of the other leg (18, 20) facing this leg (22, 24) has the abovementioned opposite contact surface (42, 44) forms.

REPLACEMENT LEAF

2. rack rod according to claim 1, characterized in that the angular parts are each formed as U-shaped brackets (10, 12), the base (14, 16) of which can be screwed onto the rack (2), two opposite ones in each case Legs (18, 22 or 20, 24) of a pair of clamps (10, 12) each form a holding device (8) on opposite sides of the frame bar (2).

3. Rack rod according to claim 2, characterized in that in each pair of brackets (10, 12) the two legs (22, 24) of the one bracket (12) are each provided with a recess (34, 36) and the end faces of the two legs (18, 20) of the other bracket (10) each define the opposite contact surface (42, 44).

4. Rack rod according to claim 2 or 3, characterized in that the two brackets (10, 12) of a pair of brackets have substantially the same cross section.

5. Rack rod according to one of the preceding claims, characterized in that the rack rod (2) for each pair of angular parts or brackets (10, 12) has a single, continuous threaded bore (28).

6. Rack rod according to one of the preceding claims, characterized in that the longitudinal edges of the rack rod (2) are chamfered.

SPARE BLADE

7. Rack rod according to one of claims 2 to 6, characterized in that the outer, the base (14 or 16) and the legs (18, 20 or 22, 24) connecting longitudinal edges of the brackets (10, 12) are chamfered .

8. Rack rod according to one of the preceding claims, characterized in that the legs (18, 20, 22, 24) are each provided on their undersides with an insertion bevel.

9. Rack rod according to one of the preceding claims, characterized in that the contact surfaces (42, 44) of the legs (18, 20, 22, 24) are provided with at least one elevation (52, 54).

10. Rack bar according to one of the preceding claims, characterized in that the rolling body is designed as a disc (46, 48).

11. Rack rod according to one of the preceding claims, characterized in that the insertion slot (26) is arranged substantially centrally with respect to the rack rod (2).

REPLACEMENT LEAF