CH657736A5 - MACHINE-analyzing AUTOMATIC PRINTED CIRCUITS. - Google Patents

Description

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1. Automatic analysis machine for printed circuits of the type using a control unit (5) equipped with a plurality of plugs (13), electrically connected to a computer, suitable for connection with homologated perforated control points arranged on a printed circuit (6 ) to be analyzed, said control unit (5) being movable perpendicularly with respect to the storage plane of said printed circuit (6) allowing the insertion of part of said pins (13) within said control points, characterized in that it comprises: - a feed conveyor (30) movable horizontally with direction of advancement with respect to said control unit (5); - a loading device (31) of the printed circuits (6) to be analyzed, located upstream of said control unit (5) with respect to said direction of advancement, adapted to take, individually, the same from a stack (21) acting from warehouse, and to place them on said feed conveyor (30); - an abutment element (40), transversal with respect to said direction of advancement, placed in correspondence with said control unit (5) adapted to allow the interception and positioning, in correspondence of said pins (13), of each circuit printed (6) in transit on said control unit (5), said abutment element (40) being perpendicularly mobile, according to predetermined operating steps, with respect to said forward direction of said feed conveyor (30), means (43) being provided for locking said feed conveyor (30) during the control phase of each printed circuit (6) of said control unit (5); - an automatic device (49) for selecting and separating said printed circuits (6), located downstream of said control unit (5), electrically connected to said computer and controlled by it.

Machine according to claim 1, characterized in that said feed conveyor (30) comprises a pair of parallel motorized horizontal belts (30) on which respectively two opposing lateral ends of each printed circuit (6) coming from said stack ( 21) acting as a warehouse, the distance between said parallel belts (30) being adjustable, said belts (30) mounted on corresponding pulleys (29-29 ') adjustable in axial direction on their rotation shafts.

Machine according to claim 2, characterized in that the stack (21) acting as a warehouse is arranged above said pair of parallel belts (30) and is delimited by four mounted (22) connected inferiorly, two by two, to corresponding longitudinal structural elements (24) placed externally to said belts (30) and essentially parallel to them, said longitudinal structural elements (24) being supported by transverse bars (25) on which they are adjustable in position by varying their distance, at least two of said uprights (22) being adjustable in a longitudinal position with respect to said longitudinal structural elements (24), each being equipped at the bottom with a shoe (22 ') inserted in a corresponding longitudinal guide (23') obtained on each of said structural elements (24 ).

Machine according to claim 1, characterized in that said loading device (31) of the printed circuits to be analyzed consists of a plurality of protrusions (32-33), alternatively movable in a transverse direction with respect to said feed direction and places at the bottom of said stack (21) of printed circuits, said plurality of projections (32-33) being constituted, on each of the two sides of said stack (21) by a first series of support projections (32) aligned horizontally and movable simultaneously between them by a second series of shaped projections (33), also aligned horizontally at a higher level than the first and movable simultaneously with each other in synchronization alternately with said first support projections (32) according to a sequence of phases such as to allow the deposition by fall of a single printed circuit (6) on said feed conveyor (30), each of said shaped projections (33) having its own end (33 ' ) acting on the lateral edge of said printed circuits (6) provided with horizontal grooves (39) each having a height corresponding to the thickness (S) of a single printed circuit (6).

5. Machine according to claim 4, characterized in that said supporting projections (32) and said shaped projections (33) are connected to two corresponding series of control levers (35-35 ') operated by horizontal rods (36-36 ') each controlled by a pneumatic jack (37-37').

Machine according to claim 1, characterized in that said transversal striker element (40) comprises a horizontal plate (40) operated, according to said predetermined operating steps, by means of an electromagnet (48) placed below it, said plate ( 40) being equipped with a horizontal ledge edge (41), perpendicular to said direction of advancement, suitable for intercepting and positioning a printed circuit (6) on said control unit (5).

Machine according to claim 1, characterized in that said means (43) adapted to block said feed conveyor (30) consist of a microswitch (43) intercepted individually by each printed circuit (6), arranged in correspondence with said striker element (40) is electrically connected to the motor (28) of said feed conveyor (30).

Machine according to claim 1, characterized in that downstream of said control unit (5) with respect to said feed direction and in correspondence with said automatic device (49) for selecting and separating the printed circuits (6) is provided an evacuation conveyor (57) consisting of a pair of motorized parallel horizontal belts (57), mounted on corresponding pulleys (56-58), on which respectively the two opposing lateral ends rest in a printed circuit (6).

Machine according to claim 8, characterized in that said automatic device (49) for selecting and separating said printed circuits (6) is constituted by a pneumatic jack (59) controlled by said processor, placed in correspondence with said conveyor of evacuation (57), suitable to allow the reciprocal removal, transversely to the direction of motion of said avacuation conveyor (57), of said pulleys (56-58) of said second pair of belts (57), this mutual removal causing the fall of said printed circuit (6) on a collection shelf underneath said evacuation conveyor (57).

As is known, the verification of the printed circuits is carried out in analyzer machines equipped with suitable control units electrically connected to a computer capable of instantly verifying the goodness, or not, of each printed circuit subjected to the control test. More specifically, the control units essentially consist of a plurality of metal pins, arranged in such a way as to form a sort of horizontal «bed» (usually indicated in the sector with the English term «bed of nails» = «bed of nails ») on which they are positioned according to a grid, suitable for being inserted within the corresponding perforated control points present on the printed circuit board. The insertion of the metal pins within the control points of the printed circuit occurs by moving the horizontal plane of storage of the «bed» in a direction normal to the plate of the printed circuit.

Currently, in accordance with the technique known up to now, the positioning of each printed circuit on the machine control unit is mostly carried out manually by an operator who takes the printed circuits from a warehouse, places them in the machine and therefore,

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after checking, to separate them from the defective ones based on the signaling of the computer.

This procedure is obviously disadvantageous with reference, on the one hand, to the required operating times and, on the other hand, to the high costs deriving from the use of the personnel constantly engaged in the control operations. Furthermore, due to direct human intervention, errors cannot be excluded both in the phase of separation of the controlled circuits and during the positioning phase of each printed circuit on the control unit.

To overcome these drawbacks, automatic analyzer machines have been developed where the feeding of the printed circuits is carried out using an inclined plane, acting as a chute, along which the printed circuits themselves coming from a warehouse reach, by gravity, the control. These machines, structurally very complex, are intended exclusively for the control of printed circuits produced in large series (for use on very consumer products such as, for example, televisions, household appliances, etc.) therefore having all the same dimensions (limited) and a relatively small number of control points. The main drawback of these machines is therefore due to their rigidity of use, being intended exclusively for the control of printed circuits of only one type and, in any case, of small dimensions.

The essential object of the present invention is therefore to overcome the drawbacks mentioned, relating to the technique known up to now, by realizing a machine with which it is possible to automatically carry out the feeding, control and separation of printed circuits of various sizes, also relatively high, with great reliability and operating speed with consequent economic and technological advantages. This and other objects are all achieved by the automatic printed circuit board analysis machine of the type using a control unit equipped with a plurality of plugs, electrically connected to a computer, suitable for connecting with homologous perforated control points arranged on a circuit printed to be analyzed, said control unit being movable perpendicularly with respect to the storage plane of said printed circuit allowing the insertion of part of said plugs into said control points, characterized in that it comprises: - a feed conveyor movable horizontally with progress with respect to said control unit; - a device for loading the printed circuits to be analyzed, located upstream of said control unit with respect to said direction of advancement, adapted to take them individually from a stack acting as a warehouse, and to place them on said feed conveyor; - an abutment element, transversal with respect to said direction of advancement, placed in correspondence with said control unit suitable to allow the interception and positioning, in correspondence of said pins, of each printed circuit in transit on said control unit, said striker element being perpendicularly movable, according to predetermined operating steps, with respect to said direction of advancement of said feed conveyor, means being provided for locking said feed conveyor during the control phase of each printed circuit of said control unit ; - an automatic device for selecting and separating said printed circuits, located downstream of said control unit, electrically connected to said computer and controlled by it.

Advantageously, in accordance with an embodiment of the present invention, the feed conveyor consists of a pair of parallel motorized horizontal belts on which respectively two opposing lateral ends of each printed circuit rest, the distance between said parallel belts being adjustable in according to the dimensions of the printed circuits to be analyzed, said belts being mounted on corresponding pulleys adjustable in axial direction on their rotation shafts.

Further characteristics and advantages of the present invention will become clearer from the detailed description that follows of a preferred embodiment, illustrated purely by way of non-limiting example in the accompanying drawings, wherein:

- figure I shows the schematic top view of the machine with some parts removed to better highlight others;

- Figure 2 shows a top view of the control levers of the mobile projections suitable for loading the printed circuit boards to be analyzed onto the feeding conveyor;

- figure 3 shows the longitudinal section of part of the machine, made according to the line III-III of figure 1;

- figure 4 shows the cross section of part of the machine, made according to the line IV-IV of fig. 1.

With reference to the attached drawings, the machine object of the present invention has been indicated with (1) as a whole. From an overall point of view, the machine (1) essentially consists of a central part (2), comprising a control unit (5), a power supply part (3) of the printed circuits (6) to be analyzed and an end part (4) for evacuating and separating the controlled printed circuits (6).

The central part (2) essentially comprises a traditional printed circuit board analysis machine consisting (figs. 1 and 4) of a quadrangular structure (7) supported by four threaded bars (8), driven by a chain (9) and wheels. toothed (10), by a motor (11), on which is mounted a horizontal plate (12) movable in vertical direction with upward or downward motion according to the direction of rotation of the threaded rods (8).

On the horizontal plate (12) is fixed a small part of metal pins (13) (fig. 4), arranged in a grid in a per se known way, which are electrically connected to an electronic processor not shown in the figures. Above the bed (13) there is arranged, in a fixed horizontal position with respect to the plate (12), an exclusion mask (14), supported by shelves (15) integral with the structure (7), which is equipped with through holes (16 ), placed at the bed (13), distributed according to the particular configuration of the printed circuits (6) to be analyzed.

On the upper part, the central part (2) is equipped with a horizontal flat cover (17), slightly spaced from the underlying exclusion mask (14) so as to create a crack with a thickness (D) slightly greater than the thickness (S) of a printed circuit (6). The cover (17) is movable in the horizontal plane, in a known manner, in such a way as to allow inspections or manual interventions in the area below it, being driven, by means of a wheel (18), by a motor (19) (fig. 1).

The feeding part (3) of the machine (1) is supported by a pair of side members (20) fixed externally to one end of the structure (7). It should be noted that this fact is advantageous in itself since it allows to modify, according to the invention, machines of the known type without substantial interventions on the main components of the machines themselves.

With particular reference to Figures 1 and 3, indicated with (21) a stack of printed circuits (6) acting as a warehouse delimited on the corners by four vertical uprights (22), having an L-section; resting inferiorly on the horizontal edges (23) of a pair of longitudinal structural elements (24) parallel to each other supported by transverse bars (25) fixed, at their ends, to the side members (20). Two of the vertical uprights (22) are adjustable in position with respect to the elements (24), each being equipped at the bottom with a shoe (22 ') slidingly inserted in longitudinal guides (23') obtained on the edges (23) of the elements (24). These elements (24) are in turn adjustable in a transverse position (so as to vary their distance) being connected to the bars (25) by means of sleeves (26) which can be fixed by means of locking screws not shown in the figures.

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With this it is possible to adapt the described structure to any size (within certain limits) of the printed circuits (6) to be analyzed.

At the end of the side members (20) a shaft (27) pivoted transversely pivoted by a motor (28), on which two pairs of pulleys (29) are keyed (also adjustable transversely along the shaft (27)) on which is mounted a pair of parallel belts (30), constituting the feeding conveyor of the printed circuits (6), which, driven by the motor (28), move in the horizontal plane with the direction of travel (indicated with the arrows in fig 1) with respect to the control unit (5). The belts (30) are mounted, on a band opposite to the control unit (5), on corresponding return pulleys (29 '), as shown in fig. 1, removably fixed on the structure (7) so as to be able to be moved away or brought closer according to the dimensions of the printed circuits (6). To clarify what is illustrated in the figure, it should be noted that the pulleys (29) and (29 ') are respectively arranged in pairs for each belt (30), as a further underlying transmission is provided (indicated with (29' ') in fig. 3 ) and this in order to keep the belt (30) itself in the horizontal plane both as regards its active part (advancing towards the control unit (5)) and the inactive part (returning).

The belts (30) are arranged below the stack (21) so as to be in correspondence with the lateral edges of the printed circuits (6) which are gradually positioned on them by means of a loading device (31) illustrated in figures 2 and 3.

This loading device (31) consists of a double series of projections (32) and (33) arranged on the structural elements (24) and facing inside the area between them. More in detail, on each element (24) are arranged, aligned longitudinally, the supporting projections (32) and, at a slightly higher level, the shaped projections (33) also aligned longitudinally and staggered with respect to the former. The projections (32) and (33) consist of essentially cylindrical elements, housed in through seats (34) obtained in the structural elements (24), which are movable alternately in a transverse direction with respect to the direction of advancement of the belts (30) and protruding inside the structural elements (24) themselves. On the outside of each of these, the projections (32) and (33) are respectively hinged, each with control levers (35) and (35 ') (fig. 2) operated by means of two horizontal rods (36) and ( 36 ') controlled by corresponding pneumatic jacks (37) and (37').

At the bottom of the stack (21), at the height corresponding to the supporting projections (32), there is a first microswitch (38) (fig. 3), activated by each printed circuit 6, electrically connected to the pneumatic jacks (37) and (37 ') and suitable for controlling the following operating phases of the loading device (31). In a first step, the pile (21) is supported by the projections (32) (protruding from the elements 24) while the projections (33) are internal to the seats (34). Subsequently the projections (33) (which have a head (33 ') equipped with horizontal grooves (39) having thicknesses corresponding to the thickness (S) of each printed circuit (6) come out of the seats (34) and intervene on the pile (21) pressing in a perpendicular direction to it intercepting the lateral edges of the printed circuits (6) starting from the penultimate from below. At this point the projections (32) retract, letting a printed circuit (6) fall on the belts (30) (the last , forming the bottom of the pile (21) while the pile (21) is supported by the projections (33). Subsequently the projections (32) come out while the projections (33) re-enter causing the pile (21) to descend on the projections (32). The cycle resumes The microswitch (38), intercepted by the printed circuit board (6) at the bottom of the battery (21), triggers the starting of the phases described above, in fact if there are no more printed circuits (6) in the battery (21 ), the microswitch (38) remains deactivated stopping consequently m the loading device (31). The printed circuit board (6) loaded on the belts (30) then reaches the control unit (5) where a transverse striker element (40) is provided which is suitable for intercepting and positioning, at the bed (13), of the printed circuit board (6) itself.

This abutment element (40) consists of a horizontal plate (figs. 1 and 3) interposed between the belts (30) immediately downstream of the bed (13) with respect to the direction of advancement of these. It is equipped with a horizontal stop edge (41) perpendicular to the direction of advancement of the circuit (6) whose angular position is adjustable in the horizontal plane by means of adjustment screws (42). At this edge (41) there is a second microswitch (43) which, intercepted by the printed circuit (6), causes the belts (30) to lock being electrically connected to the motor (28). The striker element (40) is vertically movable being driven by an electromagnet (48) (shown schematically in fig. 3) housed below it and acting on a pair of vertical cylinders (44) supporting the inserted element (40) within corresponding holes in the structure (7).

The vertical movements of the striker element (40) are programmed. It is protruding above the exclusion mask (14) so as to be able to intercept the printed circuit board (6) carried by the belts (30) which slide above the mask (14) itself (fig. 4). As soon as the printed circuit (6) activates the microswitch (43), the belts (30) stop and the plate (12) goes up by inserting the bed pins (13) into the holes (16) of the mask (14) and, through they, at the control points of the printed circuit (6). Once the check has been carried out, the plate (12) goes down, the striker element (40) is lowered, operated by the electromagnet (48), and the belts (30) start moving away the printed circuit (6) downstream of the control unit (5). And the cycle starts again.

With particular reference to Figures 3 and 4, a further pair of belts arranged above and parallel to the belts (30) is indicated with (45). These belts (45), mounted on corresponding motorized pulleys (46) (similarly to the belts (30) so as to be lying in the horizontal plane) are arranged immediately downstream of the loading device (31) for the entire longitudinal extension of the underlying belts (30). The function of the belts (45) is to remedy any warping of the printed circuit board (6) coming from the stack (21) (which can occur in the case of relatively large printed circuits) while maintaining the printed circuit board (6 ) itself in a horizontal plane between the two pairs of belts (30) and (45).

As can be seen, in particular, from figure 4, the belts (30) and (45) slide within the thickness slot (D) identified by the mask (14) and by the cover (17) below which a cover sheet can be arranged (47) placed in contact with the belts (30) and (45).

Downstream of the control unit (5), there is the terminal part (4) of the machine (1) where an automatic device (49) for separating the printed circuits (6) is provided.

The end part (4) consists of a pair of longitudinal structural elements (50) (fig. 1), similar to the elements (24), equipped with sleeves (51) mounted on transverse bars (52) supported at the ends by a pair of support longitudinal members (53) fixed to the structure (7).

This constructional solution is also advantageous in that it allows to modify machines of the known type without particular interventions on their main components.

A shaft (54) is transversely pivoted at the end of the side members (53), driven by a motor (55), carrying two pulleys (56) on which are mounted respectively two belts (57) constituting the evacuation conveyor of the printed circuits ( 6). At the opposite end, the belts (57) (movable according to the direction indicated by the arrows in fig. 1) are mounted on return pulleys (58) connected to the ends of the elements

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(50). The distance between the belts (57), similarly to what has been described above, is adjustable according to the dimensions of the printed circuits (6) by appropriately positioning the sleeves (51) on the bars (52) and the pulleys (56) on the shaft ( 54).

The automatic device (49) for separating the circuits (6) analyzed, consists of a pneumatic jack (59) and opposing stems fixed transversely to the elements (50) below the horizontal plane of storage of the belts (57) which is electrically connected to the computer which, on the basis of the data collected on the circuit (6) analyzed in the control unit (5), commands its movements in the transverse direction. In correspondence with the jack (59), above it near one of the two belts (57), there is a third microswitch (60) adapted to be intercepted by the printed circuits (6) in transit. This microswitch (60), which is connected to the computer, has the function of signaling to the computer itself the presence at that point of the machine of a printed circuit (6).

Having memorized the sequence of checks carried out on the circuits (6), the computer determines, by means of the jack (59), the opening (or not) of the elements (50) when each circuit (6) intercepts the microswitch (60).

The actuation of the jack (59) will therefore take place if the circuit (6) intercepting the microswitch (60) is found to be defective following the control previously carried out in the unit (5).

At the bottom of the terminal part (4) of the machine (1) there is a collection shelf (not shown) of the defective printed circuits (6) while downstream of the machine (1) itself, with respect to the direction of advancement of the belts (57), 5 is provided a storage device (also not shown) of the printed circuits (6) which are free from manufacturing defects.

Naturally, the operating phases of the machine (1) will be regulated in such a way as to provide a sufficient distance between the printed circuits (6) in transit on the control unit (5) and on the separation device (49).

It should be noted that the machine in question, thanks to its structure and conception, is capable of using a universal control unit and therefore suitable for controlling printed circuits of various sizes.

The invention therefore achieves the intended aim. Obviously, the invention will also be able to take on forms other than the one illustrated above in its practical embodiment; in particular, numerous modifications of a practical and functional nature may be made which will appear evident to a technician in the sector, without thereby abandoning the scope of protection of this patent. All the details can also be replaced by technically equivalent elements and the materials used, the shapes and the dimensions, can be any according to the 25 needs.

3 drawings sheets