GB2050895A

GB2050895A - Improvements to machines for grooving sheets, particularly printed- circuit sheets

Info

Publication number: GB2050895A
Application number: GB8017600A
Authority: GB
Original assignee: ORLEANS ATEL OUTILLAGE
Current assignee: ORLEANS ATEL OUTILLAGE
Priority date: 1979-06-01
Filing date: 1980-05-29
Publication date: 1981-01-14
Also published as: GB2050895B; DE8014325U1; FR2457734A1; CH635257A5; FR2457734B1; DE3020292A1

Abstract

A machine for forming in the two faces of a printed-circuit sheet L oppositely positioned grooves making it possible to break the sheet along said grooves comprises two trains of oppositely positioned rotary milling cutters I1, I2 having parallel axes. The sheets are fed from a stock P by trolleys M driven by chains C1, C2, the sheets passing into an intermediate table 5 so as to be guided between the cutters which are at an adjustable distance h. <IMAGE>

Description

SPECIFICATION Improvements to machines for grooving sheets, particularly printed-circuit sheets The invention relates to machines for grooving sheets, in particular on the two faces thereof, and especially sheets for printed circuits.

Considering more especially in what follows said sheets for printed circuits, a process is already known in which the same sheet is intended to support several circuits printed respectively on as many boards as are formed in this sheet and which are separated, for use, by breaking along grooves provided in substantially orthogonal directions, preferably on each of the faces. To give a general idea, there is shown in Figure 3 a sheet P of this kind, with two sets of grooves Q opposite each other on each side of the sheet.

For preparing such sheets a conventional cutting machine is generally used comprising one or more coaxial milling cutters. The circuit-carrying sheet is then placed on a table adapted to be moved under the tain of milling cutters, then brought back rearwards. The sheet must then be turned over and the operation begun again on the other face. This process is slow, so costly. Furthermore, it is necessary to constantly alter the adjustment of the guide stops for the sheets, so as to make sure that the second series of grooves is indeed opposite the first.

It has also already been proposed to obtain the two sets of grooves by single passes, and to this end to cause the sheets to be grooved, carried by an appropriate frame, to pass between two sets of fixed punches facing each other in pairs. This arrangement has the disadvantage that the punches wear rapidly, leading to difficulties in adjustment, and the disadvantage of slowness, because of the need to draw the frame back to its starting position after each pass.

To remedy these different disadvantages, in accordance with the invention, the tools of the machine for providing the grooves in the sheet are formed of two trains of oppositely disposed rotary milling cutters with parallel axes.

Feeding of the sheets takes place advantageously from a magazine.

The invention relates to machines for grooving sheets, in particular on the two faces thereof, and especially sheets for printed circuits.

Considering more especially in what follows said sheets for printed circuits, a process is already known in which the same sheet is intended to support several circuits printed respectively on as many boards as are formed in this sheet and which are separated, for use, by breaking along grooves provided in substantially orthogonal directions, preferably on each of the faces. To give a general idea, there is shown in Figure 3 a sheet P of this kind, with two sets of grooves 0 opposite each other on each side of the sheet.

For preparing such sheets a conventional cutting machine is generally used comprising one or more coaxial milling cutters. The circuit-carrying sheet is then placed on a table adapted to be moved under the train of milling cutters, then brought back rearwards. The sheet must then be turned over and the operation begun again on the other face. This process is slow, so costly. Furthermore, it is necessary to constantly alter the adjustment.of the guide stops for the sheets, so as to make sure that the second series of grooves is indeed opposite the first.

Feeding of the sheets takes place advantageously from a magazine at the base of which each sheet is driven by trolleys carried by chains, the assembly being installed preferably in a variable-width system, so as to be able to be adapted to sheets of different dimensions. To this end, for example, the chains are carried respectively by two guides, one fixed, the other situated at an adjustable distance from the first.

Other adjusting means are provided, particularly for selectively spacing the two sets of cutters apart, depending on the desired depth of the grooves.

The invention comprises, apart from these arrangements, certain others which are used preferably at the same time and which will be more explicitly discussed hereafter.

And it will, in any case, be well understood with the help of the complement of description which follows, as well as the accompanying drawings, which complement and drawings are of course given especially by way of indication.

Figure 1 of these drawings shows in perspective, with parts cut away, a machine for grooving sheets of printed circuits, constructed in accordance with the invention.

Figure 2 shows separately and schematically, in perspective, the cutting system which this machine comprises.

Figure 3 shows, by way of indication, a printed circuit sheet, to be grooved in accordance with the invention.

Figure 4 illustrates separately, in section and on an enlarged scale, cutting elements.

Figure 5, finally, shows separately and on an enlarged scale, in perspective and with parts cut away, a feeding trolley which said machine comprises.

In accordance with the invention, desiring to proceed with the double grooving of printed circuit sheets, so as to then be able to readily separate the boards thus formed, the following or similar is the way to set about it.

Sheets P, suitably fed and guided, are caused to pass through the gap separating two trains of milling cutters themselves spaced apart at suitable distances, depending on the spacing of the grooves Q to be provided.

To this end, a machine is used for example of the kind such as shown in Figure 1 and comprising essentially on a frame A: - - two guides B and C positioned parallel to each other at adjustable distances, one B being for example fixed whereas the other C is adjustable, particularly by means of a screw system N or any other device, - - conveyor chains C1 and C2, mounted along said guides and adapted to feed, by means of trolleys such as shown schematically at M, the sheets P to be grooved, - an adjustable magazine L for sheets P, this magazine being disposed above the path of the chains so that, by appropriate drive means such as fingers carried by trolleys M and cooperating with the orifices of the sheets (or by any other means), said trolleys ensure the transfer to the cutter system of sheet P situated at the base, - two trains of milling cutters It 12 mounted on superimposed shafts I, supported by frames E, F and able to be set at adjustable distances h, by means of an adjustment system not shown in detail and operable for example at R, said shafts being controlled preferably from individual motors H and frames, E, F, or at least one of them at G, being themselves, if necessary, able to be adjusted so as to present therebetween a selectively adjustable distance, - - an intermediate table S, adapted to receive the sheet P to be grooved leaving magazine L, and to hold it there so as to ensure the formation of grooves Q, said sheet being able to receive, during at least a part of its travel, the weight of a pressure cylinder K, - - finally, a receiving member J at the outlet of the assembly, to receive the sheet which has just been treated.

It should be noted, with respect to intermediate table S, that the cutters Ii of one of the two trains 11 12 must travel therethrough. Since adjustment of the spacing of the cutters is provided, depending on the spacing to be provided between the grooves, this table is formed of several elements, as shown in Figure 2, these elements being supported by rods T on which they are secured in position, after adjustment, by means of screws U1 or by any other means.

By way of indication, there is shown schematically in Figure 5 a device for feeding each sheet P, at the base of magazine L, by means of a finger U of trolley M. This finger U, carried by a support base V and slidably mounted in said trolley, is retracted on entering the magazine by means of a ramp X. Said base V slides initially along a rail Y, by means of a bearing roller Z. Finger U is then retracted at the moment when it reaches the first ramp X, then it rises again on arriving at the second ramp X and thus engages in a corresponding orifice provided in sheet P to be fed.

To facilitate the operations it is advantageous to provide momentary slowing down of the trolley, which may be obtained for example by a magnetic brake acting remotely on the motor driving chains Ca c2.

Finally, the whole of the machine will be controlled from an appropriate control panel, visible at D.

Following which, a machine may be constructed whose operation is evident from what has gone before and may be resumed in the following way.

With the machine previously adjusted to comply with the spacing and depth of the grooves, by means of the different adjusting means which it comprises, a certain number of sheets Pare piled up in the magazine and motors H and chains C1 C2 are brought into operation. Thus the sheets are fed one by one at the outlet of the magazine, then grooves are formed in the same direction simultaneously on the two faces. The sheets thus treated are discharged at J and they may then be reintroduced, after adjustment and after a 90 rotation, into the magazine, so as to provide grooving in the direction orthogonal to the preceding one.

The rapidity of operation is then considerable and, at the same time, the maximum security is provided insofar as the coincidence of the grooves on the two faces is concerned.

The invention presents then numerous advantages in comparison with aiready-existing processes and machines of the kind in question, particularly: - possibility of working continuously and at high speed, because particularly of the fact that the cutters wear out and overheat relatively little, the cutting stress of a milling cutter being distributed over a relatively large length of the cutting edge if it is compared with that of a fixed punch, - accuracy and cleanness of the work; ; - flexibility of adjustment, allowing in particular grooves to be formed having different spacing and/or different depths in sheets of distinct thicknesses, - and possibility of forming grooves on a single side of the sheets, if so desired, since the two motors H are independent and since furthermore it may be arranged, by adjusting the positions of shafts I, for one of the trains of cutters to be put out of action.

As is evident, and as it follows moreover already from what has gone before, the invention is in no wise limited to those of its modes of application and embodiments which have been more specially considered; it embraces, on the contrary, all variations thereof.

Claims

1. A machine for grooving sheets on both faces thereof so as to make possible their subsequent breaking along these grooves, comprising two lines of tools capable of grooving respectively these two faces, and means for causing the sheets to pass between these tools, characterized in that said tools are formed by two trains of oppositely positioned rotary milling cutters having parallel axes.

2. The machine as claimed in claim 1, characterized in that it comprises, in addition to the two trains of cutters, a sheet magazine and a chain conveyor system adapted to feed successively the sheets leaving the magazine, so as to cause them to pass between the two trains of cutters.

3. The machine as claimed in claim 2, characterized by the fact that the distance between the drive chains, as well as the corresponding dimension of the magazine, are adjustable.

4. The machine as claimed in claim 3, characterized by the fact that it comprises two guides one of which is fixed and the other adjustable in position, these guides carrying respectively the two chains and the corresponding walls of the magazine.

5. The machine as claimed in any one of claims 2 to 4, characterized by the fact that the feeding of the sheets by means of the chains takes place with the assistance of trolleys carried by said chains and provided with interlocking means adapted to cooperate with corresponding elements of the sheets to convey them to the discharge station.

6. The machine as claimed in claim 5, characterized by the fact that the interlocking means are of the finger type capable of cooperating with holes provided in the sheets.

7. The machine as claimed in claims 5 and 6, characterized by the fact that the fingers are slidably mounted in the trolleys so as to be retracted on entering the magazine, then to project again so as to penetrate into the holes of the sheets.

8. The machine as claimed in any one of Claims 5 to 7, characterized by the fact that means are provided for slowing down the running of the trolleys at the moment when they engage with the sheet to be fed.

9. The machine as claimed in any one of the preceding claims, characterised by the fact that the sheet leaving the magazine is received on a table through which travel the cutters of one of the two trains of cutters, said table being preferably constructed from several removable and adjustable elements.

10. The machine as claimed in any one of the preceding claims, characterised by the fact that the two trains of cutters are carried by supports capable of being adjusted in position in relation to each other.

11. The machine as claimed in any one of the preceding claims, characterised by the fact that the two trains of cutters are adjustably mounted on their supports, so as to allow the distance separating them to be adjusted depending on the thickness of the sheets and/or of the depth of the grooves.

12. A machine for grooving sheets on both faces thereof, substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.