GB2031184A

GB2031184A - A device for positioning a part under viewing apparatus

Info

Publication number: GB2031184A
Application number: GB7932146A
Authority: GB
Original assignee: Alcatel CIT SA; Compagnie Industrielle de Telecommunication CIT Alcatel SA
Current assignee: Alcatel CIT SA
Priority date: 1978-09-21
Filing date: 1979-09-17
Publication date: 1980-04-16
Also published as: BE878813A; IT7968844A0; FR2437030B1; FR2437030A1; NL7906984A; GB2031184B; DE2937533A1; LU81702A1; CH632348A5; IT1119167B

Abstract

A small object e.g. a printed circuit as seen through viewing apparatus is to be moved by a positioning device so that it occupies a desired position and orientation. During movement the object (5) is lifted clear of a support (3) by a retractible rod (10). In previous devices the rod has been rotatable about its own axis. This makes it difficult to match the position of the object with a reference position since the axis of rotation of the object as viewed is displaced by translation of the object. This is overcome by mounting the means for translating the rod (15, 16, 17, 18, 19) on a turntable 11 arranged to rotate about a vertical axis which is unaffected by the means for translating the rod. <IMAGE>

Description

SPECIFICATION A device for positioning a part under viewing apparatus The present invention relates to a device for positioning a small size, generally plane part under viewing apparatus, the device comprising a vertically movable rod for lifting the part above a support on which it is to be positioned, means for moving the rod in two perpendicular directions in a horizontal plane, and means for rotating the rod about a vertical axis.

As a general rule with such a device, the small part is observed through a microscope equipped with cross-wires to define a reference point. In operation, the small part is moved in a horizontal plane until a corresponding reference point on the part is aligned with the cross-wires, and then, when necessary, the part is rotated to obtain a desired angular position.

Unfortunately, on known devices, the means for moving the small part horizontally also move the axis of rotation by the same amount as the small part is moved, with the result that any correction of angular position also results in a disalignment of the reference point and the cross-wires. The part must therefore be positioned by successive approximations, which takes a relatively long time, particularly when the positioning must be very accurate.

Preferred embodiments of the present invention provide a part positioning device which avoids such trial and error, which are both fast and accurate to use and which make it possible to position a long series of parts in a production line at a rate equal to that at which they are processed by the rest of the line.

The present invention provides a device for positioning a small size, generally plane part under a viewing apparatus, the device comprising a vertically movable rod for lifting the small part off a support relative to which it is to be positioned, means for moving the rod in two perpendicular directions in a horizontal plane, and means for rotating the rod together with the said means for moving the rod in two perpendicular directions about a vertical axis which is unaffected by the said means for moving the rod in two perpendicular directions.

Preferably the means for rotating the rod comprise a turntable on which the rod and the said means for moving it in two perpendicular directions are mounted. The turntable may include a handle projecting therefrom for manual rotation thereof.

In a preferred embodiment the means for moving the rod in two horizontal directions comprises: a first platen mounted on the turntable and free to slide thereon in a first horizontal direction relative thereto; a second platen mounted on the first platen and free to slide thereon in a second horizontal direction perpendicular to the said first horizontal direction; and a lever freely pivoted about a point of the turntable and linked with the second platen, whereby movement of the lever causes the second platen to move relative to the turntable in any direction in a horizontal plane, the rod being mounted on the second platen.

It is advantageous if the rod includes means for moving it vertically downwards to a rest position, said means further serving to return both the means for rotating the rod and the means for moving it in a horizontal plane to respective rest positions.

The invention also provides an assembly comprising viewing apparatus and the above-defined positioning device, the viewing apparatus including a sight aligned with the vertical axis for rotation of the positioning device.

A device for positioning printed circuits on a support for their further processing is described below by way of example with reference to the figures of the accompanying drawings, in which: - Figure 1 is an elevation of the device with viewing apparatus mounted thereon; and - Figure 2 is a section through the housing which supports the positioning mechanism.

The device comprises a housing 1, having an upper plane surface with two studs such as 2 projecting therefrom for positioning a printed circuit suction support thereon, the support being provided with a suction channel 4. A printed circuit 5 is placed on the support 3 to be accurately positioned relative thereto.

Viewing takes place using a binocular microscope having two objective lenses 6 whose separation is adjustable by means of a knurled knob 7 thereby adjusting the plane in which the binocular images coincide. The eye pieces 8 are adjustable by means of a rotatable knob 9 so that the image can be observed; alternatively the image may be projected on a television screen.

Avertical rod 10 mounted on a turntable 11 passes through a bore 12 in a plate 13. The rod is normally held in a low position by a helical spring 14, but it is upwardly moveable by means of a jack, not shown, in order to lift the printed circuit 5 a few tenths of a millimetre.

The device for moving in two perpendicular directions in a horizontal plane is as follows. The plate 13 is supported on two superposed platens 15 and 16, the platen 16 being slidable in one direction on the turntable 11 and carrying the platen 15, while the platen 15 is slidable in a perpendicular direction on the paten 16. A lever 17 has a fixed point 18 fast with the turntable 11 and is articulated at a point 19 which is fast with the plate 13. The lever is movable in two vertical perpendicular planes, as shown in figure 2: in the plane of the figure and in the perpendicular plane. It can be seen that when the vertical rod 10 is raised and supports the printed circuit, operating the lever 17 makes it possible to move the printed circuit in two perpendicular directions so as to bring a predetermined point on the printed circuit into coincidence with a sight (e.g.

cross-wires) in the microscope. Since the axis of the turntable 11 is arranged to coincide with the sight there then only remains to adjust the angular position of the printed circuit.

The angular adjustment is performed by means of a handle 22 which is fast to the turntable 11 which is itself free to rotate on a base plate 23.

When the rod 10 is lowered again after positioning the printed circuit, it is automatically returned to its initial position both in a horizontal plane with respect to the base and angularly with respect to the plate, by a camming arrangement between a lug which engages in a cone, one of these items being fast with the rod and the other with the plate or with the base (not shown).

It is worth observing that although the X-Y frame of reference is, in theory, rotated by rotating the turntable 11, so far as an operator of the device is concerned, the lever 17 can continue to be moved along the same X and Y directions as before regardless of the rotation. The only point at which the operator needs to take care is to let the lever 17 move freely while he is rotating the part by means of the handle 22. Even in an alternative system in which the operator's control of X-Y displacement is more indirect, e.g. by means of a potentiometer joystick that does not rotate with the turntable but which controls electric X and Y actuators that do rotate with the turntable, the operator can still readily use his joystick to accurately position the part in the viewing apparatus simply by paying attention to the image rather than to his joystick-operating hand.

The invention is applicable in particular to positioning circuits (e.g. integrated and printed circuits) which are to be measured or which are to be processed at one or several points on their surfaces (e.g. by connecting leads thereto).

Claims

1. A device for positioning a small size, generally plane part under a viewing apparatus, the device comprising a vertically movable rod for lifting the small part off a support relative to which it is to be positioned, means for moving the rod in two perpendicular directions in a horizontal plane, and means for rotating the rod together with means for moving the rod in two perpendicular directions about a vertical axis which is unaffected by the said means for moving the rod in two perpendicular directions.

2. A positioning according to claim 1, wherein the means for rotating the rod comprise a turntable on which the rod and the said means for moving it in two perpendicular directions are mounted.

3. A positioning device according to claim 2, wherein the turntable includes a handle projecting therefrom for manual rotation thereof.

4. A positioning device according to claim 2 or 3, wherein the means for moving the rod in two horizontal directions comprises: a first platen mounted on the turntable and free to slide thereon in a first horizontal direction relative thereto; a second platen mounted on the first platen and free to slide thereon in a second horizontal direction perpendicularto the said first horizontal direction; and a lever freely pivoted about a point of the turntable and linked with the second platen, whereby movement of the lever causes the second platen to move relative to the turntable in any direction in a horizontal plane, the rod being mounted on the second platen.

5. A positioning device according to any preceding claim, wherein the rod includes means for moving it vertically downwards to a rest position, said means further serving to return both the means for rotating the rod and the means for moving it in a horizontal plane to respective rest positions.

6. A device for positioning a small size, generally plane part under a viewing apparatus, the device being substantially as herein described with reference to and as illustrated in figure 2 of the accompanying drawings.

7. An assembly comprising a viewing apparatus and the positioning device of any preceding claim, the viewing apparatus including a sight aligned with the vertical axis for rotation of the positioning device.

8. An assembly comprising a viewing apparatus and the positioning device of any one of claims 1 to 6, the assembly being substantially as herein described with reference to and as illustrated in figure 1 of the accompanying drawings.