Apparatus for detaching platelets which are adhering to a strip

Abstract

Apparatus for detaching platelets which are adhering to a strip of ribbon comprises a holder for the ribbon wound to form a ribbon coil and a deflecting edge on the holder. The ribbon withdrawn from the spool is guided over the deflecting edge and as a result is deflected through about 180.degree.. The platelets are arranged on the side of the ribbon which is directed away from the deflecting edge and are largely detached from the ribbon in passing over the deflecting edge because of their inherent rigidity. A manually actuated transport mechanism on the holder comprises a driver element which, with the actuation of transport mechanism, presses a part of the ribbon already drawn off the ribbon spool against a slide surface on the holder and so displaces it on the said surface that another section of the ribbon is drawn off the ribbon spool.

Description

BACKGROUND OF THE INVENTION

At the present time, the production of printed circuits is normally effected by first of all producing an enlarged original, which is then reduced in size photographically. On the original, the conductor tracks are stuck on to the drawing support in the form of black strips. Circular black platelets having a central hole are used for soldering points, which platelets are likewise stuck on to the drawing support. In similar manner, other drawing symbols in the form of platelets are applied to the drawing support.

It is known to arrange the platelets which represent, for example, soldering points or other symbols, on a supporting strip or ribbon. The platelets are for this purpose provided with an adhesive coating, which permits a self-bonding adhesion of the platelets on the support ribbon. The adhesive bond which is thereby formed is however not very strong; in actual fact, because the ribbon is guided with its side not provided with platelets around a sharp guiding edge, it is possible for the platelets to be extensively detached from the support ribbon because of their inherent rigidity.

With the known apparatus, it is necessary for the ribbon to be drawn off by hand from the ribbon spool clamped in the holding means. Since a relatively strong friction occurs at the sharp deflection edge, a fairly strong pulling force has to be applied. For this purpose, it is necessary for the holding means to be held in one hand, while the ribbon is pulled off the spool with the other hand. The platelet thereby being detached cannot however be immediately gripped, since no hand is available for this gripping action. The gripping of the platelet and the transfer to another support can in fact only be carried out when the stripping is completed and the platelet has either fallen off or assumes a more or less favourable receiving position in the holding means.

Another disadvantage of the known apparatus is that the stripping or transfer cannot be effected with the desired continuity, because of the said strong friction. On the contrary, the transferring operation generally takes place with a jerky action, so that the feed cannot be controlled. Thus, it can, for example, happen that when an appropriate force is applied, such a large section of the ribbon is stripped off the ribbon spool that simultaneously two or more platelets are detached, and these in their turn stick to one another.

SUMMARY OF THE INVENTION

The invention accordingly has for its object to improve an apparatus of the type as described above in such a way that the stripping or withdrawal of the ribbon from the ribbon spool and hence the detachment of the platelets from the ribbon can be effected in a definite manner and with much smaller application of force, using only one hand, so that the other hand is free for the transfer of the platelet being detached.

With the known apparatus, the guide edge is formed by one edge of a guide plate, the ribbon being first of all guided along the one side of the guide plate, then around the edge and thereafter over the other side of said plate. The housing for the ribbon spool is arranged on the side of the guide plate over which the ribbon is first guided. Disposed on the other side is a stripper device, which tapers off to the guide edge. The stripper is connected fast to the apparatus, so that it is impossible for platelets being detached from the ribbon to be transferred directly to the support, for example, the drawing support, by correspondingly bringing the apparatus up to the support.

This disadvantage is avoided with the apparatus according to the invention by a construction which permits the platelets being detached to be rolled directly on to the drawing support.

An extraordinarily high positioning accuracy can be achieved by appropriate shifting of the apparatus.

It is to be further mentioned in this connection that it is also known to arrange platelets on a transparent strip or ribbon and in such a way that a portion of each platelet projects over the edge of the ribbon. The transfer is then effected by the ribbon being stretched with both hands over the drawing support and displaced until the platelet which is to be deposited is disposed above the envisaged position. Pressure is then applied with the thumb of one hand and from above to the platelet, so that the latter adheres to the drawing support. In this connection, however, the disadvantage arises that the vision of the operator is obstructed by his own thumb just at the moment of pressing down the platelet. The consequence thereof is that eventually errors in positioning can still occur.

This is impossible with the apparatus according to the invention, in that the apparatus rests on one side, with a side wall on the drawing support, while on the other side, using the free hand for pressing down the platelet being detached, the operator can so guide a pin-like object to the position in question that he still has sufficient visual control.

In the present invention the effect is obtained that the ribbon, in passing around the first wire, is even deflected by more than 180.degree., whereby the detachment of the platelets is further assisted.

In the present invention a stirrup member is swung into the swivelled position in which the free end of the stirrup member extends alongside the first wire, and it is thereby possible to achieve the result that the platelets to be released are not directly deposited on the support to be transferred, but initially on the free end of the stirrup member. This still makes possible a supplementary readjustment of the apparatus, in order that the platelets are deposited with the maximum possible accuracy on the support, for example, on the drawing support.

By means of an adapter it is possible for the platelets being detached to be initially set down on the mounting surface. From this position, they can then be transferred with a special transfer instrument to a new support. This is particularly expedient when the support is too small or difficulty accessible, for example, for the mounting of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

One constructional example of the invention is hereinafter described by reference to the drawings, wherein:

FIG. 1 is a side elevation of the apparatus according to the invention;

FIG. 2 is a front view of the apparatus shown in FIG. 1;

FIG. 3 is a top plan view of the apparatus which is shown in FIG. 1;

FIG. 4 is an underneath plan view of the apparatus which is shown in FIG. 1;

FIG. 5 is a view similar to that of FIG. 1, but in which that side wall of the holding means and of the ribbon spool housing facing the observer are removed;

FIG. 6 is a top plan view of the adapter;

FIG. 7 is a section through the adapter which is shown in FIG. 6;

FIG. 8 is an enlarged view of the forward portion of the apparatus according to the invention with the adapter fitted.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The apparatus according to the invention consists of a holding means 1 having two side walls 2, 3 and a bottom wall 4. Arranged in the holder 1 is a ribbon spool housing 6 with a ribbon spool 7. The ribbon spool housing 6 is formed with a slot 33 for the ribbon 8 which is to be withdrawn from the ribbon spool 7.

The ribbon 8 is covered with platelets 9, which adhere to the ribbon 8 by means of an adhesive coating which is provided on said platelets. In the present case, it is intended that the platelets 9 should be positioned on a drawing support, which is to serve as an original for a printed circuit. Accordingly, the platelets 9 represent soldering lugs.

The bottom wall 5 is provided at its one end with a recess 25, in which are tensioned two wires 26, 27. The ribbon which is pulled off the ribbon spool 7, after passing through the slot 33, travels first of all over a guide pin 29, which extends between the two side walls 2, 3 of the holder 1. The strip then travels beneath the wire 26 and obliquely upwards over the wire 27. The platelets 9 are arranged on that side of the ribbon 8 which is remote from the wire 27 as the ribbon travels around the wire. The ribbon runs almost completely around the wire 27 and is then once again guided underneath the wire 26 and on to the inside of the bottom wall 4 of the holder 1. As illustrated in FIG. 5, the section of the ribbon extending from the wire 26 to the wire 27 forms an acute angle with that section of the ribbon which is running from the wire 27 to the wire 26. The inside of the bottom wall 4 forms a slide surface 5. In running around the wire 27, the platelets 9 are detached almost completely from the ribbon 8, because of their natural rigidity.

The withdrawal of the ribbon is effected by means of a transport mechanism. This consists of a two-armed lever 10, which is rotatable about a shaft 11, which extends between the two side walls 2, 3. Provided at the bottom end of the lever 10 is a driver element 15. This element can be pivoted about a pivot shaft 17 which is arranged on the lever 10. The said element 15 is provided at its bottom end with a cutting edge 16. The cutting edge 16, with the slide surface 5, forms an acute angle facing the feeding direction.

A coiled torsion spring 12 is wound around the pivot shaft 11 of the transporting lever 10. One end 13 of the said coiled spring 12 bears against the said lever 10. The other end 14 bears against a connecting pin 24 between the two side walls 2, 3 of the holder 1. This end 14 of the said spring 12 serves for holding the ribbon spool housing 6 in the holder 1.

By means of a coiled torsion spring 20, the driver element 15 is forced with its cutting edge downwardly towards the ribbon 8 resting on the slide surface 5. So that the ribbon 8 may not bulge upwardly on the slide surface 5 before the driver element 15, a retainer spring 19 is also provided above the said surface 5, which spring is wound around a connecting pin 18 between the two side walls 2, 3 of the holder 1.

The transport lever 10 is swivellable between two end positions, the coiled torsion spring 12 tending to hold the said lever in the end position which is shown in FIGS. 1 and 5. This end position is defined on the one side by the connecting pin 23 and on the other side by a stop head 22. The stop head 22 is on a screw 21 which can be turned in the transporting lever 10. When the screw 21 is so rotated that the said head 22 is moved towards the right, the transporting stroke or travel can thereby be reduced. The other end position is defined by the connecting pin 24, against which the lever 10 strikes when its upper arm is swung towards the right.

Formed in the side wall 3 of the holder 1 is a hole 32, which is in alignment with a hole 31 in the ribbon spool housing 6 and the central hole of the ribbon spool 7. When the apparatus is being used, it is now possible for the top portion of the thumb of the left hand to be introduced into the holes 31, 32, while the upper end of the transporting lever 10 is moved towards the left with the fingers. In this case, the driver element 15, with its cutting edge 16, shifts the ribbon 8 bearing on the slide surface 5 towards the left. The effect of this displacement is that another section of ribbon is pulled off the ribbon spool 7. When the transporting lever 10 is released again, the cutting edge 16 slides back on the ribbon 8 towards the right, without carrying the said ribbon with it. This ratchet mechanism is assisted by the retainer spring 19. Provided on the right end of the holder is a stirrup member 28, which is pivotable about the connecting pin 29. The free end 30 of the stirrup 28 extends parallel to the wire 27 when the stirrup is in the lowered position. Consequently, a platelet 9 being detached does not drop directly on to the support, on which is mounted the bottom wall 4 of the holder 1, but the platelet 9 is lowered on to the free end 30 of the stirrup 28. Consequently, it is possible for the apparatus, prior to the final depositing of the platelet 9 on the support, to be once again displaced, so that the position for the depositing operation is accurately adjusted. However, it is also possible for the platelet 9 being respectively detached to be immediately deposited on to the support; in this case, the stirrup has to be swung upwardly.

Also provided on the holder is a sleeve 34, on which the end of a ribbon can be fixed, and on which the apparatus can for example be suspended from a drawing board which is disposed vertically or substantially vertically. It is also possible to guide the ribbon around a guide roller and to fix a counter-weight on the other end of the ribbon.

If it should not be desirable for the platelets which are being detached to be directly transferred from the apparatus to a new support, for example, on to a drawing support, but for the transfer to be effected by means of a special pointed instrument, an adapter 35 can be mounted on the right-hand end of the holder. This is shown in FIGS. 6 and 7. How the fitting is effected can be seen from FIG. 8.

The adapter 35 consists of a block member 36, on to which is screwed a fork-shaped clamping member 37 with two clamping arms 38, 39. Arranged on the block 36 between the clamping arms 38, 39 is a circular mounting plate 40 consisting of silicon rubber. A hole 41 is formed in this circular plate 40. Formed in the block 36 underneath this hole 41 is another hole 42 which is in alignment therewith.

With the mounting of the adapter 35, the two clamping arms 38, 39 are pushed over flanks which surround the recess 25 in the bottom plate 4. As can be seen from FIG. 8, the platelets 9 now roll directly on the plate 40. The silicone rubber guarantees that the adhesion between the surface of the depositing plate 40 and the deposited platelet 9 is very small, so that the platelet 9 can easily be lifted off the plate 40 by means of a pointed instrument, which is introduced into the hole in the platelet 9.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

Claims

I claim:

1. Apparatus for detaching platelets which are adhering to a strip or ribbon, for the purpose of transferring the platelets to another support, more particularly for the production of originals for printed circuits, comprising a holder for the ribbon wound to form a ribbon coil and a deflecting edge on the holder, over which the ribbon withdrawn from the ribbon spool is guided and as a result is deflected through about 180.degree. the platelets being arranged on that side of the ribbon which is directed away from the deflecting edge and are largely detached from the ribbon in passing over the deflecting edge, because of their inherent rigidity, characterized by a transport mechanism to be manually actuated on the holder which comprises a driver element which, with the actuation of the transport mechanism, presses a part of the ribbon already drawn off the ribbon spool against a slide surface on the holder and so displaces it on the said surface that another section of the ribbon is drawn off the ribbon spool and further characterized in that the transport mechanism is formed by a transport lever which is pivotable on the holder about a pivot shaft at a mid part of the lever to provide an upper lever arm for manual actuation and a lower lever arm mounting the driver element, said driver element having an upper end pivotally mounted on the lower lever arm about a pivot shaft which is parallel to the pivot axis of the transport lever and having a lower cutting edge which is disposed so that the angle formed between the cutting edge and the plane of the slide surface for the ribbon is an acute angle facing in the direction of ribbon movement over the slide surface.

2. Apparatus according to claim 1 characterized in that the driver element comprises a toothed cutting edge.

3. Apparatus according to claim 1, characterized in that the holder is provided with a resilient retainer member which is arranged above the slide surface before the driver element when seen in the direction of advance of the ribbon and tends to prevent any upward bulging of the ribbon running on the slide surface with the return movement of the dirver element after completing a feeding stroke.

4. Apparatus for detaching platelets which are adhering to a strip or ribbon, for the purpose of transferring the platelets to another support, more particularly for the production of originals for printed circuits, comprising a holder for the ribbon wound to form a ribbon coil and a deflecting edge on the holder, over which the ribbon withdrawn from the ribbon spool is guided and as a result is deflected through about 180.degree., the platelets being arranged on that side of the ribbon which is directed away from the deflecting edge and are largely detached from the ribbon in passing over the deflecting edge, because of their inherent rigidity, characterized by a transport mechanism to be manually actuated on the holder which comprises a driver element which, with the actuation of the transport mechanism, presses a part of the ribbon already drawn off the ribbon spool against a slide surface on the holder and so displaces it on the said surface that another section of the ribbon is drawn off the ribbon spool, and further characterized in that the transport mechanism is formed by a transport lever which is pivotable on the holder about a pivot shaft at a mid part of the lever to provide an upper lever arm for manual actuation and a lower lever arm mounting the driver element, the ribbon spool being arranged in a box-shaped housing, which is provided with a passage slot for the ribbon which is drawn off, characterized in that a coiled torsion spring extends around the pivot shaft of the transport lever and of which a projecting end bears against the end of the transport lever, while its other projecting end bears on the ribbon spool housing and holds the latter in the holder.

5. Apparatus according to claim 4, in which at least one side of the ribbon spool housing is made flat, characterized in that the ribbon spool housing rests with the said flat side on the ribbon travelling on the slide surface, and that the other projecting end of the coiled torsion spring presses against that side of the ribbon spool housing which is opposite the said flat side.

6. Apparatus for detaching platelets which are adhering to a strip or ribbon, for the purpose of transferring the platelets to another support, more particularly for the production of originals for printed circuits, comprising a holder for the ribbon wound to form a ribbon coil and a deflecting edge on the holder, over which the ribbon withdrawn from the ribbon spool is guided and as a result is deflected through about 180.degree., the platelets being arranged on that side of the ribbon which is directed away from the deflecting edge and are largely detached from the ribbon in passing over the deflecting edge, because of their inherent rigidity, characterized by a transport mechanism to be manually actuated on the holder which comprises a driver element which, with the actuation of the transport mechanism, presses a part of the ribbon already drawn off the ribbon spool against a slide surface on the holder and so displaces it on the said surface that another section of the ribbon is drawn off the ribbon spool and further characterized in that the slide surface is formed by the inside of a side wall belonging to the holder and that the deflecting edge is formed by a first wire which is tensioned transversely of the ribbon-feeding direction in a recess formed on one end of the side wall, the holder being adapted to be mounted with the outside of this side wall on the support to which the platelets are to be transferred.

7. Apparatus according to claim 6, characterized in that a second wire is tensioned in the recess parallel to the first wire, and that the ribbon to which platelets are attached and which is drawn off the ribbon spool is guided from above the slide surface beneath the second wire, around the first wire, once again beneath the second wire and through on to the slide surface, that section of the ribbon extending from the second wire to the first wire forming beneath the second wire an acute angle with that section of the ribbon which is running from the first wire to the second wire.

8. Apparatus according to claim 6, characterized in that the holder has provided thereon a pivotable stirrup member movable between a first, lower position parallel to the first wire and a second, upper position removed from the first wire, the free end of which is so arranged that it extends, in a pivoted position of the stirrup, approximately parallel to the first wire on its side remote from the second wire, and that the distance between the free end of the stirrup and the first wire is so chosen that the platelets which are detached from the ribbon, when the latter is running around tha first wire, are deposited on the free end of the stirrup.

9. Apparatus according to claim 6, characterized in that an adapter is provided which can be fitted on that end of the side wall which is formed with the recess, said adapter comprising a mounting surface for the platelets which are detached from the ribbon when the latter runs around the first wire, and that the said surface is formed with a hole.

10. Apparatus according to claim 9, characterized in that the mounting surface consists of silicone rubber.

11. Apparatus for detaching platelets which are adhering to a strip or ribbon, for the purpose of transferring the platelets to another support, more particularly for the production of originals for printed circuits, comprising a holder for the ribbon wound to form a ribbon coil and a deflecting edge on the holder, over which the ribbon withdrawn from the ribbon spool is guided and as a result is deflected through about 180.degree., the platelets being arranged on that side of the ribbon which is directed away from the deflecting edge and are largely detached from the ribbon in passing over the deflecting edge, because of their inherent rigidity, characterized by a transport mechanism to be manually actuated on the holder which comprises a driver element which, with the actuation of the transport mechanism, presses a part of the ribbon already drawn off the ribbon spool against a slide surface on the holder and so displaces it on the said surface that another section of the ribbon is drawn off the ribbon spool and further characterized in that the holder is formed with a hole which is in alignment with the central ribbon spool hole when the ribbon spool and the ribbon spool housing are in the inserted position, so that the tip of the thumb of the hand with which the apparatus is to be actuated can be inserted through both holes and the transporting means can be actuated with the remaining fingers.