IE53353B1

IE53353B1 - A method of attaching a printed circuit board to an electroplating frame,and of detaching the board from the frame after electroplating

Info

Publication number: IE53353B1
Application number: IE1765/82A
Authority: IE
Original assignee: Schering Ag
Priority date: 1981-07-24
Filing date: 1982-07-23
Publication date: 1988-10-26
Also published as: JPS6130075U; IE821765L; IT8220539A0; DE3129909A1; FR2510341B1; JPS5825499A; GB2104816B; IT1190756B; GB2104816A; CH657243A5; FR2510341A1

Abstract

The apparatus comprises rotary drive means 1 for screwing in and unscrewing the attachment screws 9 which mount the circuit boards 16 on the frame 15. The drive means is capable of engaging simultaneously a plurality of screw heads lying in substantially the same plane, and preferably comprises a plurality of independently operable pneumatically-powered drive units 5 with an individual detector switch to control each drive in accordance with the operation required.

Description

This invention relates to a method of attaching a printed circuit board to an electroplating frame, and of detaching the board from the frame after electroplating, respectively by screwing in and unscrewing attachment screws which are mounted on a support bar of the electroplating frame, and is concerned more especially with screwing in and unscrewing screws which are mounted in the electroplating frame in the same plane on both sides of a central cross-member.

There has been no previous proposal to use apparatus of this kind for mounting/demounting printed circuit boards in electroplating frames. Until now, the printed circuit boards have in each case been attached to or detached from electroplating frames manually by screwing in and unscrewing crossbar-headed screws. This is not only a particularly time-consuming procedure, but it also naturally leads to differences in pressure exerted on the printed circuit boards.

Xt is an object of the invention to provide an electroplating method using apparatus which can carry out mechanically and with a defined pressure the attachment and detachment of printed circuit boards on electroplating frames.

The present invention provides a method of attaching a printed circuit board to an electroplating frame, and of detaching the board from the frame after electroplating, respectively by screwing in and unscrewing attach ment screws which axe mounted on a support bar of the frame, the method including the use of apparatus comprising rotary drive means to screw in and unscrew the attachment screws, the rotary drive means comprising a plurality of rotary drive units and being capable of engaging simultaneously a corresponding plurality of screw heads lying in substantially the same plane. - 3 One or more of the following features may be incorporated in advantageous forms of apparatus for use according to the invention:(a) Each rotary drive unit is operated by a rack-and-pinion mechanism. (b) There is pneumatic drive means for the or each rack-and-pinion mechanism. (c) There is provided means for varying the torque applied to the or each rotary drive unit.

Preferably, when the rotary drive means is pressure-driven, the said torque-variation means comprises a drive-pressure regulating valve. (d) Each rotary drive unit includes a splined drive shaft provided with a screw-engagement coupling member which is axially movable along the splined shaft, and there is provided means for spring-biassing each coupling member into screw-engagement position. Such apparatus preferably includes disengagement means for moving each coupling member out of screw-engagement position against the action of the springbiassing means. The disengagement means is advantageously pneumatically operated and may comprise a movable plate. (e) There is provided means for locating an electroplating frame in position during operation of the rotary drive means. Such locating means may include one or more locating blocks and/or one or more locking sliders. (f) There is provided inductive or other detector switching means, preferably mounted adjacent - 4 to the rotary drive means, for controlling the operation thereof. tg) The rotary drive units are independently operable so that, in carrying out the method, either all or only some of the drive units are operated as necessary.

Apparatus for use according to the invention can be made in a form suitable for semi-automatic screwing-in and unscrewing of suitably headed screws which are mounted in an electroplating frame in the same piane on both sides of a central cross-member, and the invention is primarily concerned with such applications.

The screws will normally be cross-bar or toggle-headed, but other types of head may be used.

The following is a general description of the structure and operation of preferred forms of apparatus for use according to the invention:The rotary drive means comprises a plurality of independently operable rotary drive units. Rotary movement of each rotary drive unit is produced by means of a toothed rack which drives a spindle by way of a pinion. The toothed rack is in each case actuated by means of a pneumatic cylinder. As a result of the independence of the individual rotary drive units it is possible, in an optimum manner, in a suitable frame, to open and close the individual units with the same air pressure and independently with regard to timing.

The arrangement is advantageously such that the same air pressure produces the same torque for each of the screws on the electroplating frame. This torque is preferably adjustable by way of a pressure-regulating valve with manometer, and produces the corresponding gripping force when the printed circuit boards to be electroplated are being clamped. - 5 Each rotary drive unit is provided with a screwengagement coupling member. The latter is mounted on a splined shaft so as to be movable in an axial direction, and is pressed upwards by means of a spring towards the headed screws of the electroplating frame.

During the rotary movement the screw engages in the coupling member and rotates with the latter until either the toothed rack reaches the corresponding end position and the movement thus stops, or the resistance produced by the clamping of the printed circuit board is greater than the force produced by the pneumatic cylinder.

All the coupling members can be pulled downwards pneumatically by cylinders by way of an engaging plate in order that even when the electroplating frame is inserted the toothed rack may be pushed into the lefthand or right-hand normal position without the capstanheaded screws being engaged. In order to be able to insert the frame into the apparatus without hindrance, the coupling members can also be pulled down out of the way in the manner described. The electroplating frame is fixed in suitably shaped locating blocks and secured by pneumatically actuated locking sliders against lifting off.

The operation on the apparatus used according to the invention 533Ϊ.3 - 6 is very simple.

Before inserting each frame, the apparatus is set into the normal position in order to bring the toothed racks to the aero pesition.

The normal position may lie either on the lefthand or the right-hand side of the machine, depending on whether the operation starts with the headed screws in the open or closed position.

The opening travel and closing operations are monitored and controlled by means of inductive switches which are in each case mounted near the rotary drives.

One form of apparatus for use in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which Figure 1 shows a cross-section through the apparatus; Figure 2 shows a longitudinal section through the apparatus; Figure 3 is a detail plan view of the apparatus; Figures 4A and 4B show an electroplating frame with screws mounted with their heads in the same plane on both sides of a central cross-member.

Referring to Figure 1, there are shown screws (9) which clamp printed circuit boards (16) onto an electroplating frame (15) and are arranged to engage in the coupling member (7) of a rotary drive (1) when 3 3 53 - 7 the frame (15) is introduced into the apparatus.

The coupling members (7) are arranged to be axially movable on a splined shaft (6). The splined shaft (8) is connected by way of a sleeve (17) to a spindle (4) which carries, at its lower end, a pinion (3) which is not shown in Figure 1. The pinion engages in a toothed rack (2) which is connected by way of a connecting-piece (18) to the piston rod (19) of a pneumatic cylinder (5). The torque applied in tightening the screws f9) can be altered by way of the pressure of the compressed air fed to the pneumatic cylinder (5). A regulating means (6) is provided for this purpose.

In order that the printed circuit boards (16) may be inserted into the clamping apertures (34) of the electroplating frame at the correct level, supporting rods (21) which are adjustable in height are arranged on a work-table (20) of the apparatus. The supporting rods (21) also accommodate inductive switches (14), 2o the signals from which are evaluated for the automatic control of the device.

In order to allow the frame (15)· to be inserted and clamped in a precise position in the apparatus, the coupling members (7) must first be pulled down25 wards out of the way. This is cone by means of an engaging plate (11), which is also actuated pneumatically. - 8 After the frame (15) has been inserted, the engaging plate (11) is moved upwards and the coupling members (7), which are subject to spring pressure, engage in the cross-bar-headed screws (9) of the electroplating frame.

Figure 2 shows a spring (10) which produces the spring pressure on the coupling members (7).

Figure 2 also shows the position cf the pinion (3) which engages in the - 9 toothed rack (2). A locating block (12) serves to fix the electroplating frame (15) in the correct position.

A pneumatic cylinder (23) is connected to the engaging plate (11) and on actuation pulls the latter downwards, taking with it the coupling members (7).

Figure 3 shows an extract from a plan view of the apparatus. The electroplating frame (15) indicated is inserted in the device. It is fixed laterally by means of a retaining angle (24) and held down by a locking slider (13). Both the extended position (25) and the withdrawn position (26) of the slider are shown. The slider is also moved by means of a pneumatic cylinder. Figure 3 shows that with each rotary drive (1) there is associated an inductive switch (14) which registers whether there is a printed, circuit board present at that point and whether it has to be attached or released.

As a result, it is possible to set into operation only the rotary drives (1) that are required in each case.

Figures 4A and 4B show a complete electroplating frame (15), consisting of a frame head (27), support bar (28), clamps (29) with the clamping apertures (34) and the screws (9). By means of a handwheel (31) and pressure screw (32) the frame (15) can be clamped to a rail (33). Whilst hanging on the rail (33, the frame (15), or several frames at the same time, can be transported through the treatment stations of the electroplating plant.

From the side view (Figure 4B) it can be seen that the operating crossbar toggles of the screws (9) all lie S3333 -loin one plan·, whilst iron the front view (Figure 4A) it can he aeen that the screws are arranged on both aides of the central support bar (28). 533 93 - 11 The following key summarises the reference numerals used ia the drawings:- 1· Rotary drives 24. Retaining angle 2. Toothed racks 25. Extended position 3. Pinion 26. Withdrawn position 4· Spindle 27. Frame head 5. Pneumatic cylinder 28. Support bar 6. Regulating means 29. Clamps 7· Coupling member 30. Screws 6. Splined shaft '31. Eandwheel 9. Screws 32. Pressure Screw 10. Spring 33. · Rail 11. Engaging plate 12. Locating blocks 13. Locking slider 14. Inductive switches 15. Electroplating frame 16. Printed circuit boards 17. Sleeve 18. Connecting-piece 19. Piston rod 20. Work-table 21 . Supporting bar 23. Pneumatic cylinder 34. Clamping aperture

Claims

1. A method of attaching a printed circuit board to an electroplating frame, and of detaching the board from the frame after electroplating, respectively by screwing in and 5 unscrewing attachment screws which are mounted on a support bar of the frame, the method including the use of apparatus comprising rotary drive means to screw in and unscrew the attachment screws, the rotary drive means comprising a plurality of rotary drive units and being capable of engaging 10 simultaneously a corresponding plurality of screw heads lying in substantially the same plane.

2. A method as claimed in claim 1, wherein each rotary drive unit is operated by a rack-and-pinion mechanism.

3. A method as claimed in claim 2, wherein the said 15 apparatus includes pneumatic drive means for the or each rack-and-pinion mechanism.

4. A method as claimed in any one of claims 1 to 3, wherein the said apparatus includes means for varying the torque applied to each rotary drive unit. 20

5. A method as claimed in claim 4, wherein the rotary drive means is pressure-driven and the said torque variation means comprises a drive-pressure regulating valve.

6. A method as claimed in any one of claims 1 to 5, wherein each rotary drive unit includes a splined drive shaft provided 25 with a screw-engagement coupling member which is axially movable along the splined shaft, and there is provided means for spring-biassing each coupling member into screw-engagement - 13 position.

7. A method as claimed in claim 6, wherein the said apparatus includes disengagement means for moving each coupling member out of screw-engagement position against the action of the spring-biassing means.

8. A method as claimed in claim 7, wherein the disengagement means is pneumatically operated.

9. A method as claimed in claim 7 or claim 8, wherein the disengagement means comprises a movable plate.

10. A method as claimed in any one of claims 1 to 9, wherein the said apparatus includes means for locating an electroplating frame in position during operation of the rotary drive means.

11. A method as claimed in claim 10, wherein the said locating means includes one or more locating blocks.

12. A method as claimed in claim 10 or claim 11, wherein the said locating means includes one or more locking sliders.

13. A method as claimed in any one of claims 1 to 12, wherein the said apparatus includes inductive switching means for controlling the operation of the rotary drive means.

14. A method as claimed in claim 13, wherein the inductive switching means is mounted adjacent to the rotary drive means.

15. A method as claimed in any one of claims 1 to 14, wherein the rotary drive means is capable of engaging a 533 5 3 - 14 plurality of screw heads lying in substantially the same plane but distributed in an array on both sides of a central support member in an electroplating frame.

16. A method as claimed in any one of claims 1 to 15, in 5 which the rotary drive units are independently operable so that, in carrying out the method, either all or only some of the drive units are operated as necessary.

17. A method as claimed in claim 1, in which the said apparatus is substantially as hereinbefore described with 10 reference to, and as shown in, the accompanying drawings.