Mechanical device for inspecting parts

Abstract

The invention relates to a mechanical device for inspecting rotationally symmetrical parts (6) or machined parts. The mechanical device is suitable for a vertical optical inspection apparatus comprising an image sensor (1) and an observation surface (7). The mechanical device comprises a stationary base (3), a frame (4) that is tiltably mounted on the stationary base (3), and one or more positioning elements (5) mounted on the tiltable frame (4). The or each positioning element (5) is arranged to receive at least one part (6) of which an image can be captured by the image sensor (1) of the vertical optical inspection apparatus when the stationary base (3) of the mechanical device is positioned on the observation surface (7) of the apparatus (7). The mechanical device is arranged to allow the frame (4) comprising the or each positioning element (5) to tilt so as to position the axis of rotational symmetry of the or each rotationally symmetrical part (6), or a face to be inspected of the or each machined part, perpendicularly to the optical axis of the vertical optical inspection apparatus.

Description

MECHANICAL DEVICE FOR PARTS INSPECTION Technical field

[0001] The present invention relates to a mechanical device for inspecting parts, for example parts manufactured by turning, folded stamped parts or machined parts, with an optical control means whose elements are arranged in a vertical axis. State of the art

[0002] Machined, stamped, folded and machined parts frequently have a variety of geometries that make them difficult to position, orient and maintain during inspection with so-called vertical optical inspection devices.

[0003] The difference in the diameters and heights of the faces of the parts to be inspected means that when some parts are placed directly on the horizontal measuring table, which is perpendicular to the optical axis of the inspection device, they position themselves wobbly and sometimes roll on the table. This results in potential instability and a lack of perpendicularity to the optical axis of the inspection device. Under these conditions, the detection of the contours of the profile of the parts used for their measurement is potentially distorted and the parts cannot be inspected accurately and repeatably.

[0004] There are various solutions and approaches to solving these positioning problems. Generally, a pose that supports and compensates for the dimensional differences of the support areas will be used.

[0005] For parts of revolution, when the geometry and material of the parts allow it, we will use as much as possible an approach of axial positioning. This can take the form of positioning on a pin or clamping between two point keys for parts with axial drilling, or with hollow keys for parts without drilling.

[0006] There are also partial magnetic levitation positioning methods, as well as vacuum suction holding methods. All of these methods have the advantage of ensuring perpendicular positioning of the parts because they align with axial areas of the part. However, they have the disadvantage of sometimes masking or hindering the detection of part of the part to be measured.

[0007] There are also positioning devices supported on V-shaped profiles. Depending on the thickness of the holding profile, which can be made very thin, the hidden part of the part is marginal and therefore does not interfere with the measurement. However, this method requires a compensation adjustment of the dimensional differential between the two support zones in order to obtain the perpendicularity of the part. The thinness of the support surface of such a device can make the positioning of small parts or parts whose center of gravity is very off-axis unstable and ergonomically complicated.

[0008] Other approaches eliminate the need for alignment to some extent by positioning the parts between two inclined transparent walls. In these devices, the part is oriented in the direction of gravity and if it makes good contact with both walls along its entire length, it can be measured perpendicularly provided that it is observed in a horizontal plane and therefore perpendicular to the optical axis of a vertical type device. The disadvantage of this method is the need to have a control device whose optical control axis is arranged in a horizontal axis, which is not the norm, or to arrange angle return devices so that the image coming from a horizontal axis is transferred to a vertically oriented optical sensor. The degree of inclination of the transparent walls remains limited because if the angle were to be too wide, the edges of the walls could hinder the correct horizontal detection of the part to be measured. As a result, parts with a significant difference between their two support diameters over a short length will not make contact with the two walls symmetrically and therefore cannot be measured. As a final possible drawback, it should be noted that the measurement of images of parts obtained through one or more intermediate surfaces, however transparent they may be, can be subject to reflections and distortions of the image.

[0009] For stamped, folded and machined parts that do not lie flat and which by definition are not parts of revolution, they will most frequently be clamped in a fixed clamp if the clamping area allows perpendicular alignment of the face to be measured or in a rotating clamp which will be oriented until a perpendicular position is obtained.

[0010] All the methods described above have certain advantages and disadvantages. Depending on the size of the parts to be measured, each may at some point prove more suitable than the others. The smaller the size of the parts to be measured, the more complicated the ergonomics of their positioning and the sensitivity of profile contour detection become. Under these conditions, some of the methods described are no longer applicable or very difficult to implement.

[0011] On the other hand, it should also be mentioned that the revolution parts can also have milled geometries such as flats, slots or transverse holes which must also be measured and whose indexing to the optical axis must be obtained.

[0012] US2021 / 0140873 discloses a modular device for laying solutions, for the dimensional and aesthetic control of small parts, using manual or automated control devices Brief summary of the invention

[0013] An aim of the present invention is to propose a mechanical device allowing easy positioning of the part to be checked, so as to minimize the risk of the part falling from its support, to ensure maximum clearance of its contour, regardless of its size and this with a vertical optical control means in direct vision (without image return).

[0014] Another object of the present invention is to provide a mechanical device allowing the alignment and indexing of specific geometries in a repeatable manner and nevertheless to minimize the number of adjustments necessary for the correct alignment of the part to be controlled.

[0015] Another aim of the present invention is to provide a mechanical device with a certain modularity so as to allow the rapid and repeatable interchange of a variety of elements for positioning and indexing parts, which are nevertheless finely adjustable.

[0016] Another object of the present invention is to provide a mechanical device having multiple housings for multi-part control while ensuring that the positioning and indexing adjustments apply to all parts in an accurate and repeatable manner.

[0017] These aims are achieved in particular by means of a mechanical device for inspecting rotating parts or machined parts. The mechanical device is adapted for a vertical optical inspection apparatus comprising an image sensor and an observation surface. This mechanical device comprises a fixed base, a frame mounted in a tilting manner on the fixed base, as well as one or more positioning elements mounted on the tilting frame. The or each positioning element is arranged to receive at least one part of which an image can be captured by the image sensor of the vertical optical inspection device when the fixed base of the mechanical device is positioned on the observation surface of the optical inspection device. The mechanical device is arranged to allow the tilting of the frame comprising the or each positioning element so as to position the axis of revolution of the part or each part of revolution or a face to be inspected of the part or each machined part perpendicular to the optical axis of the vertical optical inspection device.

[0018] In one embodiment, the optical inspection apparatus further comprises a light source.

[0019] In one embodiment, the tilting frame includes one or more stop members. The or each stop member is aligned with the or each positioning member. Alignment of the or each positioned workpiece to the respective positioning member is achieved by the stop member.

[0020] In one embodiment, the mechanical device further comprises a carriage arranged to slide relative to the fixed base and to receive by fixing the stop element(s).

[0021] In one embodiment, the or each positioning element of the part or each part comprises at least one surface whose material allows the passage of light having a wavelength making it possible to distinguish the outline of the parts to be measured.

[0022] In one embodiment, the or each positioning element of the part or each part is composed of at least two inclined surfaces on either side of a plane of symmetry parallel to the axis of the optic. These two inclined surfaces form an angle between them of between 1° and 179°, preferably between 10° and 160°.

[0023] In one embodiment, the mechanical device further comprises a removable frame adapted to be fixed on the tilting frame. The removable frame comprises receiving means for the part positioning elements.

[0024] In one embodiment, the mechanical device further comprises a backlight integral with the fixed base and arranged to illuminate the or each part through its positioning element.

[0025] In one embodiment, the element or each element for positioning the part or each part of revolution is in the form of at least two rotating cylindrical rollers arranged side by side and the rotation of which makes it possible to induce the revolution of the part of revolution.

[0026] In one embodiment, the rotation of the cylindrical rollers is induced and regulated by a motorized device.

[0027] Another aspect of the invention relates to a vertical optical inspection apparatus comprising the mechanical device according to one of the above-mentioned embodiments. Brief of the fi

[0028] Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which: - Figure 1 illustrates a perspective view of a positioning device, according to one embodiment, placed on an observation surface of a vertical optical inspection apparatus between the image sensor and the light source of the apparatus; - figure 2 illustrates a top view of the positioning device of figure 1;. - Figure 3 illustrates a partial view of figure 2 at the level of the positioning of a part of revolution aligned in abutment and in indexing by a stop element according to one embodiment; - Figure 4 illustrates a view of the positioning of a piece of revolution aligned in abutment by a stop element according to another embodiment; - Figure 5 illustrates in profile the inclination of a part positioning element and of the set of stop elements; - Figure 6 illustrates an enlarged profile view of the perpendicular positioning of a part in the positioning element of Figure 5; - Figure 7 illustrates a perspective view of a variety of stop elements; - Figure 8 illustrates a perspective view of a removable frame mounted with positioning elements in the form of glass blades assembled in pairs and each forming a V-shaped profile, according to one embodiment; - Figure 9 illustrates a perspective view of a removable frame mounted with a single positioning element in the form of a window, according to another embodiment; - Figure 10 illustrates a perspective view of a removable frame mounted with positioning elements in the form of pairs of transparent rotating cylinders, according to another embodiment; - Figure 11 illustrates a perspective view of a positioning device which comprises lighting integral with the fixed base, according to another embodiment, and - Figure 12 illustrates a perspective view of a removable frame mounted with positioning elements in the form of pairs of transparent rotating cylinders, with a device for motorizing the rotation of the cylinders, according to another embodiment. Examples of embodiments of the invention

[0029] Referring to Figure 1, the mechanical device is intended to be used with an optical inspection apparatus comprising a sensor 1 of the photographic type, for example a camera, and integrating a light source 2. Figure 1 illustrates the basic principle of the invention which consists of placing the mechanical device on an observation surface 7 of a vertical optical inspection apparatus between the light source 2 and the camera 1, then tilting the part on which are placed parts of revolution or machined parts 6 to be inspected in order to correct any possible defect of perpendicularity with respect to the optical axis of the inspection apparatus and thus obtain a precise exposure of the contours of the parts to be measured from a direct vertical view.

[0030] According to an alternative embodiment, the optical inspection device is devoid of a light source. Instead, the observation surface 7 has a visual appearance chosen to have a certain contrast with the visual appearance of the parts to be inspected in order to clearly distinguish the outline of the parts to be measured. The observation surface may typically have a white color.

[0031] The mechanical device therefore has the advantages of facilitating the positioning and indexing of small parts that are difficult to handle and whose geometric shapes and relationships do not allow precise positioning with other existing methods.

[0032] The mechanical device comprises in particular a fixed base 3 adapted to be arranged on an observation surface 7 of the optical inspection apparatus horizontally relative to the vertical axis 12 of the apparatus, a movable part 4 angularly adjustable relative to the fixed base 3 and on which one or more positioning elements 5 intended to support the parts to be measured can be mounted. The mechanical device further comprises a movable carriage 11 which slides in the horizontal axis of the fixed base 3 and which supports stop elements 8 as illustrated in particular by figures 2 to 7. More particularly, these stop elements 8 comprise a fixing part fixed on the carriage 11. These stop elements 8 make it possible to maintain the axis of revolution in particular of turned parts 6 perpendicularly relative to the vertical optical axis of the inspection apparatus as illustrated in figure 6.

[0033] The fixing part has through holes 15 (figure 7) whose shape allows lateral and height adjustment relative to the carriage 11 by means of clamping screws 14. These make it possible to lock the fixing part, respectively the stop elements 8 on the carriage 11 at the desired position within the degree of freedom permitted by the through holes 15 which are in the example illustrated oblong in shape.

[0034] The regularity and repeatability of the focal distance in Z of all the parts is thus obtained by the stop elements 8 which are mounted on the sliding carriage 11 and which align the parts.

[0035] According to one embodiment, a tilting frame 4 is mounted on the fixed base 3. The tilting frame 4 is configured to receive a removable and interchangeable frame 13. With particular reference to FIG. 8, the positioning elements comprise transparent blades 9, 10 which are mounted on the removable frame 13 and which, depending on the execution of the housings 19 of the frame 13, can be arranged in a more or less inclined manner facing each other, for example to form an angle of 120° between them. The longitudinal edges 20 of the blades are precisely beveled at the angle of the housings 19, in order to join perfectly and thus minimize the residual line visible when observing their junction vertically.

[0036] The revolution parts 6 are placed in the V-shaped profile created by the transparent blades 9, 10 inclined so that the largest of the support diameters is oriented towards the tilt axis of the frame, which corresponds to the lowest point during angular adjustment.

[0037] Referring in particular to Figure 1, the carriage 11 is arranged to slide in the longitudinal axis of the fixed base 3, in order to allow the alignment of all the parts at the same distance relative to the tilting axis 21 of the tilting frame.

[0038] According to figures 2 and 11, a manual adjustment mechanism 22 by worm screw 25 or motorized makes it possible to adjust the inclination of the tilting frame 4 until a perpendicular positioning of the axis of a part of revolution 6 or of a face of a machined or stamped part to be checked is obtained relative to the optical axis of the inspection device. The correct perpendicularity of the parts can be observed visually by assessing the focal sharpness at each end of the part. If the functionalities of the optical inspection device allow it, the perpendicularity, respectively the height in Z of the two focal points of the ends can be measured by machine autofocus functions. It is also possible on the basis of the technical drawing of the part, to calculate the angle formed by the two support points of the part relative to its central axis, thus the inclination of the device can be directly adjusted to the corresponding angle.

[0039] Depending on the degree of inclination and the weight of the parts to be checked, the stop element 8 may be retracted when measuring the parts in order to completely clear their outline.

[0040] According to another embodiment, the sliding carriage 11 which is arranged to receive the fixing part of the stop elements 8 is provided with a drum system (not shown) allowing several stop elements 8 of different configurations to be mounted therein, thus allowing rapid alternation between various stop elements 8 by rotating the drum and this in connection with the variety of parts to be measured.

[0041] According to another embodiment, the carriage 11 can be provided with alignment elements which can be tilted by rotation around an axis 23 (figure 1) perpendicular to the sliding direction of the carriage.

[0042] According to another embodiment illustrated by FIG. 9, the removable frame 13 comprises a surface for positioning machined parts which is flat, as would be a window 24 for positioning parts other than parts of revolution.

[0043] According to another embodiment illustrated by Figure 10, the removable frame 13 comprises a surface for positioning the parts consisting of cylindrical rollers 17, 18 allowing the diascopic lighting of the optical inspection device to pass through. These rollers 17, 18 can for example be transparent or sandblasted to avoid reflections due to the curvature of the cylinder. The rollers 17, 18 are rotatable, allowing the revolution of the parts for checking beats and concentricities. The rotation of the rollers can be manual or motorized 19.

[0044] According to the embodiment illustrated by figure 11, the mechanical device further comprises a backlight 16 secured to the fixed base 3 and arranged to illuminate the parts 6 through the elements of positioning 5. The optical inspection device can thus be without a light source while the inspection surface 7 can have any visual appearance.

[0045] The mechanical device may optionally also include a device (not shown) for motorizing the inclination of the tilting frame 4.

Claims

Claims 1. Mechanical device for inspecting rotating parts (6) or machined parts, the mechanical device being adapted for a vertical optical inspection apparatus comprising an image sensor (1), and an observation surface (7), the mechanical device comprising a fixed base (3), a frame (4) mounted tiltably on the fixed base (3), as well as one or more positioning elements (5) mounted on the tiltable frame (4), the or each positioning element (5) being arranged to receive at least one part (6) of which an image can be captured by the image sensor (1) of the vertical optical inspection apparatus when the fixed base (3) of the mechanical device is positioned on the observation surface (7) of said apparatus (7),in which the mechanical device is arranged to allow the tilting of the frame (4) comprising the or each positioning element (5) so as to position the axis of revolution of the part or of each part of revolution (6) or a face to be inspected of the part or of each machined part perpendicular to the optical axis of the vertical optical inspection device., 2. Mechanical device according to claim 1, wherein the tilting frame (4) comprises one or more stop elements (8), the or each stop element (8) being aligned with the or each positioning element (5), the alignment of the or each part (6) positioned on the respective positioning element (5) being obtained by said stop element (8).

3. Mechanical device according to claim 2, further comprising a carriage (11) arranged to slide relative to the fixed base (3) and to receive by fixing the stop element(s) (8).

4. Mechanical device according to one of the preceding claims, in which the or each positioning element (5) of the part or of each part (6) comprises at least one surface whose material allows the passage of light having a wavelength making it possible to distinguish the outline of the parts to be measured.

5. Mechanical device according to one of the preceding claims, in which the or each positioning element (5) of the part or each part is composed of at least two surfaces (9, 10) inclined on either side of a plane of symmetry parallel to the axis of the optic, and forming an angle between them of between 1° and 179°, preferably between 10° and 160°.

6. Mechanical device according to one of the preceding claims, further comprising a removable frame (13) adapted to be fixed on the tilting frame (4), the removable frame (13) comprising receiving means for the positioning elements (5) of the parts.

7. Mechanical device according to one of the preceding claims, further comprises a backlight (16) secured to the fixed base (3) and arranged to illuminate the or each part (6) through its positioning element (5).

8. Mechanical device according to one of the preceding claims, in which the or each positioning element (5) of the part or of each part of revolution (6) is in the form of at least two rotating cylindrical rollers (17, 18) arranged side by side and the rotation of which makes it possible to induce the revolution of the part of revolution.

9. Mechanical device according to the preceding claim, in which the rotation of the cylindrical rollers (17 and 18) is induced and regulated by a motorized device (19).

10. Vertical optical inspection apparatus comprising the mechanical device according to one of the preceding claims.

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