SHIELDING DEVICE FOR CIRCUIT BOARDS

Description

[0001] The invention relates to a shielding device for covering at least a partial area of ​​a circuit board during tempering of the circuit board in an oven, wherein the shielding device comprises a first shielding part with at least one first aperture and a second shielding part arranged opposite it with at least one second aperture, wherein an area of ​​a circuit board heated to approximately austenitizing temperature is arranged between the apertures, which is at least partially covered by the apertures, wherein the apertures are arranged opposite each other with respect to the circuit board, wherein the covered partial area of ​​the circuit board is shielded by the shielding device against further heat exposure and the uncovered area of ​​the circuit board is maintained or heated to austenitizing temperature by the heat exposure, wherein the first and the second shielding part are arranged at a distance from each other.which is larger than the thickness of the circuit board and a gap is formed between the apertures and the circuit board.

[0002] According to the invention, temperatures slightly below or above Ac3 are also detected. It is not necessary to set the Ac3 temperature precisely.

[0003] It is known in the prior art to cover parts of a circuit board by shielding it with a shielding device while heating the board in an oven. The shielding device is placed in an oven together with a circuit board heated to approximately austenitizing temperature and subjected to heat. The shielding device has a first and a second shielding part, the shielding parts being arranged opposite each other and spaced apart in the oven. The distance between the shielding parts is greater than the thickness of the circuit board, so that the circuit board can be positioned in a gap between the shielding parts without being touched by them.

[0004] The first and second shielding sections each have at least one aperture, with a portion of the circuit board positioned between the apertures and covered during heating. The spaced-apart apertures can, for example, cover a seam area of ​​the circuit board, with the seam lying between and covered by at least part of the apertures during heating.

[0005] The covered area is not heated further. A gap is provided between the apertures and the circuit board so that the apertures do not touch the board. The covered area cools slowly to a temperature below the austenitizing temperature and to a temperature slightly above the martensite start temperature, while the uncovered area of ​​the circuit board is heated to or held at the austenitizing temperature.

[0006] After a certain residence time, the blank is removed from the furnace and formed into a finished part in a forming tool and hardened. The residence time is determined such that the covered areas reach a predetermined temperature, which is below the austenitizing temperature and above the martensite start temperature, while the uncovered area is at austenitizing temperature.

[0007] Because the circuit board has areas with such different temperatures before it is formed, the formed part has corresponding areas with different strengths after forming and hardening, namely hard and soft areas or high-strength and ductile areas.

[0008] Such a shielding device is known, for example, from WO 2013 / 189597 A1, wherein cover elements are movably attached to the shielding device and can be moved over, under or around a shielded area of ​​a base body.

[0009] However, the shielding has the disadvantage that an undesirable transition zone with medium strength forms between the hard and soft areas. This transition zone arises because, when the circuit board is heated in the oven, some of the heat passes through the gap between the shielding components and through the gap between the shielding plates and the circuit board to the covered area, so that a portion of the covered area is heated despite the shielding. After the circuit board is formed, this heated area becomes the undesirable transition zone with medium strength.

[0010] In the prior art, no sharp demarcation is achieved between the area of ​​the circuit board heated or held at austenitizing temperature, which has high strength after forming, and the covered part of the circuit board, which is soft after forming.

[0011] The unwanted heat input to the covered area of ​​the circuit board slows down the cooling process, requiring a relatively long dwell time until the covered area reaches the desired temperature. During this dwell time, the uncovered area must be continuously heated. Consequently, energy consumption is high.

[0012] The object of the invention is to create a shielding device of the generic type that makes it possible to shield the covered part of the circuit board safely and in a narrowly defined manner, so that a transition area between hard and soft areas is avoided and energy can also be saved.

[0013] To solve this problem, the invention proposes that the shielding device has at least two closure bodies which are adjustable or repositioned transversely to the circuit board plane, wherein the closure bodies are spaced apart from each other and from the circuit board in a starting position and are approaching each other in a working position, such that the closure bodies are approaching each other with a gap in a first partial area of ​​the circuit board and / or are lying end-to-end against each other in a second partial area which is arranged next to the circuit board.

[0014] The closure bodies are preferably arranged in pairs on the shielding device, with one closure body being attached to the first shielding part and one closure body being attached to the second shielding part, and this pair of closure bodies being close to each other in the working position.

[0015] The shutter bodies of a pair of shutter bodies can be positioned close to each other in a first section of the circuit board during operation, so that the gaps between the shutters and the circuit board are at least partially closed and the covered section of the circuit board is reliably shielded. This virtually prevents heat from reaching the covered section of the circuit board and avoids a wide, indistinct transition zone between the hard and soft areas after the circuit board has been formed. The shutter bodies are positioned close to the circuit board, forming a gap, and preferably do not come into contact with it. This allows for cost-effective and virtually wear-free shielding.

[0016] Additionally or alternatively, the sealing elements of a sealing element pair can be positioned close together in a second area next to the circuit board in the working position, with their end faces touching. This ensures that the gap between the baffles is reliably closed and that the edge area of ​​the circuit board is shielded from the oven.

[0017] The locking elements can be designed and shaped such that part of them is positioned close to the first section of the circuit board, and another part is positioned close to each other in the second section. Such a design is possible, for example, if the locking elements have an approximately U-shaped or V-shaped cross-section, with one pair of legs being close to each other in the first section and another pair lying against each other in the second section, and the circuit board edge being arranged and shielded in a space between the legs.

[0018] The sealing elements prevent almost all heat from reaching the covered area, allowing it to cool down to the predetermined temperature more quickly. This results in a significantly shorter dwell time in the oven and considerable energy savings.

[0019] Preferably, at least one first shutter body is attached to the first aperture and at least one second shutter body is attached to the second aperture, wherein the apertures and the shutter bodies attached to them are congruent to each other and arranged opposite each other in a congruent manner.

[0020] This ensures that the shutter bodies lie exactly against each other in the working position, and the gap between the apertures and between the apertures and the circuit board is optimally sealed, so that at least virtually no heat can pass through the gap to the covered area.

[0021] Additional first shutter bodies can also be provided at the first aperture and additional second shutter bodies at the second aperture, wherein the first shutter bodies are each designed to be congruent with the second shutter bodies and are arranged in a manner identical to them.

[0022] Additional apertures with further shutter bodies can also be attached to the shielding parts in a corresponding manner.

[0023] It is preferably provided that the first shutter body in the initial position has an end face at least flush with or recessed behind a first surface of the first aperture facing the circuit board, and the second shutter body in the initial position has an end face at least flush with or recessed behind a second surface of the second aperture facing the circuit board, wherein the shutter bodies project beyond the surfaces of the apertures in the working position.

[0024] The circuit board can be easily inserted between the first and second shielding sections and positioned between the apertures without touching or tilting the shutter bodies, as long as the shutter bodies are in their initial position. Removing the circuit board is also simplified in this way.

[0025] Once the shutter assemblies are in their working position, they protrude beyond the surfaces of the apertures and at least partially close the gaps between the apertures and also between the apertures and the circuit board. Inserting or removing the circuit board is then no longer possible.

[0026] It is also preferred that the closure bodies consist of several closure parts.

[0027] Various closure parts can be assembled to form a closure body, and this also makes it possible to shield complex geometries.

[0028] Preferably, the shielding device has a recess for each shutter body in which the shutter body is guided and held displaceably transversely to the plane of the circuit board, wherein the first shutter body, when adjusted to the initial position, is completely arranged in the first recess and is at least flush with or recessed behind the first surface of the aperture facing the circuit board, wherein the second shutter body, when adjusted to the initial position, is completely arranged in the second recess and is at least flush with or recessed behind the second surface of the aperture facing the circuit board, and wherein the shutter bodies project beyond the surfaces when adjusted to the working position.

[0029] The recesses are dimensioned so that the respective shutter body is completely arranged in a recess in its initial position and its end face is preferably flush with the surface of the aperture.

[0030] The recess includes a guide that allows the locking body to be adjusted into the working position in which the locking body protrudes above the surface of the shielding part.

[0031] Furthermore, it is preferably provided that the shielding device is connected to a cooling circuit, wherein the shielding device is supplied with coolant during positioning in the oven and the closure elements are moved into the working position by a pressure set in the cooling circuit.

[0032] The cooling circuit supplies the shielding device with a coolant, which flows through the shielding device as soon as it is put into operation in the oven. The system pressure in the cooling circuit acts on the closure elements, thus adjusting them into their operating position. This allows for a particularly simple and cost-effective adjustment.

[0033] It is preferably provided that the locking elements are returned to their initial position by a spring.

[0034] The spring can, for example, be designed as a tension spring, which pulls the sealing elements back into their initial position after the system pressure in the coolant circuit drops. This solution is particularly cost-effective and easy to implement.

[0035] It is preferably provided that the locking bodies have a U-shaped cross-section, wherein the first locking body has a long first leg and a short first leg, and the second locking body has a long second leg and a short second leg, wherein in the working position the locking bodies are in close proximity to the first part of the circuit board with the short legs forming a gap, and lie against each other with the long legs in the second part.

[0036] The long legs of the sealing elements rest against each other at their ends next to the circuit board. The short legs enclose the circuit board. These are positioned close to the circuit board, with a small gap remaining between the end faces of the short legs and the circuit board to enable cost-effective and wear-free shielding.

[0037] This design of the shielding elements makes it possible to completely shield an entire edge area of ​​the circuit board with a single pair of shielding elements. Alternatively, the long and short legs can each be formed by a separate shielding element.

[0038] It is also preferred that the first shielding part and the second shielding part have further apertures with shutter bodies arranged on them.

[0039] This allows other areas of the circuit board to be shielded accordingly.

[0040] It may also be preferably provided that the shielding parts and the apertures are formed in one piece.

[0041] This enables cost-effective production of the shielding device.

[0042] Alternatively, it may be preferably provided that the shielding parts, the apertures and the shutter bodies are designed in multiple parts and are detachably connected to each other.

[0043] This allows the apertures to be exchanged, so the shielding device can be adapted to the product being shielded. The shutter bodies are preferably detachably attached to the apertures and can also be replaced. This allows, for example, the shielding device to be adapted to circuit boards of different thicknesses.

[0044] This has created a particularly flexible system that can be individually adapted to different products.

[0045] It is preferably provided that the shielding parts consist of several apertures which are assembled to form a shielding part.

[0046] An embodiment of a shielding device according to the invention is shown in the figures and explained in more detail below.

[0047] It shows: Fig. 1 a shielding device with a circuit board in a view; Fig. 2 the shielding device with the circuit board in a top view; Fig. 3 the section AA of the shielding device of the Fig. 2 .

[0048] Figure 1 Figure 1 shows a shielding device 1 for covering at least a partial area of ​​a circuit board 2 during tempering of the circuit board 2 in an oven, wherein the shielding device 1, together with a circuit board 2 heated to approximately austenitizing temperature, is placed in an oven and subjected to heat. The oven is not shown in the figures.

[0049] The shielding device 1 comprises a first shielding part 3 with a first aperture 4 and a second shielding part 5 with a second aperture 6 arranged opposite it. Both shielding parts 3, 5 have a further aperture, namely a further first aperture 4' of the first shielding part 3 and a further second aperture of the second shielding part 5, which is arranged opposite the further aperture 4' and is hidden and not visible in the figures. The first shielding part 3 is formed integrally with the apertures 4, 4'. The second shielding part 5 is also formed integrally with the aperture 6 and the further aperture. This enables cost-effective manufacturing of the shielding device 1.

[0050] The following describes the arrangement of circuit board 2 between the first aperture 4 and the second aperture 6. These descriptions also apply to the arrangement of any further section of circuit board 2 between additional pairs of apertures.

[0051] A section of the circuit board 2 is arranged between the apertures 4 and 6. This section is covered by part of the first and second apertures 4 and 6, with the covered section of the circuit board 2 being shielded against further heat exposure by the shielding device 1 and slowly cooling to a temperature below the austenitizing temperature and, for example, close to the martensite start temperature.

[0052] The uncovered area of ​​circuit board 2 is kept at or heated to austenitizing temperature by the application of heat.

[0053] Shutter elements 8 and 9 are arranged at apertures 4 and 6, ensuring improved and more precise shielding of the covered section of circuit board 2. This prevents or minimizes transition zones between hard and soft areas during subsequent forming and hardening processes. Furthermore, the improved shielding allows the sections to cool to the desired temperature more quickly, significantly reducing the dwell time of circuit board 2 in the oven and resulting in substantial energy savings.

[0054] Figure 3Figure 1 shows the first and second apertures 4, 6 and the section of circuit board 2 covered between the apertures 4, 6 in cross-section. The apertures 4, 6 are arranged at a distance from each other and from circuit board 2 such that a gap 7 is formed between circuit board 2 and the first aperture 4 and another gap 7' between circuit board 2 and the second aperture 6. Circuit board 2 is positioned between the apertures without being touched by the apertures 4, 6 or the shielding elements 3, 5. This non-contact shielding enables cost-effective and low-wear shielding.

[0055] The shutter bodies are attached to the apertures, with a first shutter body 8 attached to the first aperture 4 and a second shutter body 9, arranged opposite the first shutter body 8, attached to the second aperture 6. Both shutter bodies 8, 9 are adjusted to a working position perpendicular to each other, perpendicular to the plane of the plates. The direction of adjustment perpendicular to the plane of the plates is in Fig. 3 represented by a double arrow 27.

[0056] The first shielding section 3, with its integrally formed first and subsequent apertures 4, 4' and first shutter body 8, is congruent with the second shielding section 5, with its integrally formed first aperture 6 and subsequent aperture, as well as the second shutter body 9. Furthermore, the shielding sections 3, 5, together with the apertures 4, 6, are arranged congruently with each other. The shutter bodies 8, 9 are arranged as a pair of shutter bodies opposite each other and congruently, so that their end faces lie exactly against each other in the operating position. This ensures that the gap between the apertures 4, 6 and the gap 7, 7' between the apertures 4, 6 and the circuit board 2 are optimally sealed.

[0057] The other first and second apertures also have further first and second shutter bodies, which are attached to the shielding device 1 as shutter body pairs. These apertures and shutter bodies are correspondingly congruent and arranged identically to each other.

[0058] The paired, opposing locking bodies 8, 9 have a U-shaped cross-section. The first locking body 8 has a long first leg 19 and a short first leg 20. The second locking body 9 has a long second leg 21 and a short second leg 22. As shown in Figure 3As shown, the shutter bodies 8, 9 in their working position are each positioned with their short legs 20, 22 close to the first section 10 of the circuit board 2, creating a gap. The gaps 7, 7' between the apertures 4, 6 and the circuit board 2 are almost completely closed, preventing heat from reaching the covered section of the circuit board 2. This avoids a transition zone between the hard and soft areas after the subsequent forming of the circuit board 2. A small gap remains between the end faces of the short legs 20, 22 and the circuit board 2 to allow for contactless shielding. This makes the shielding particularly cost-effective and low-wear.

[0059] With their long legs 19, 21, the shutter bodies 8, 9 lie against each other in a second sub-area 11, which is arranged next to the plate 2. This completely closes the gap between the apertures 4, 6 next to the plate 2, preventing heat from reaching the edge area of ​​the plate 2.

[0060] The U-shaped design of the sealing elements 8, 9 allows a single pair of sealing elements to easily shield a seam area of ​​the circuit board 2. The area can cool down to the desired temperature quickly because no heat reaches the shielded area. This time saving results in significant energy savings.

[0061] As the Figure 3As shown, the shutter bodies 8, 9 are each guided and held in a recess 14, 15 of the shielding device 1 so as to be displaceable transversely to the plane of the circuit board, namely in the direction of the double arrow 27. The first shutter body 8 is attached in the first recess 14 in the first aperture 4. The second shutter body 9 is attached in the second recess 15 of the opposite aperture 6. In the initial position, which is not shown in the figures, the shutter bodies 8, 9 are completely recessed in their respective recesses 14, 15, so that the end face of the first shutter body 8 is flush with one of the first surfaces 12 of the aperture 4 facing the circuit board 2, and the end face of the second shutter body 9 is flush with one of the second surfaces 13 of the aperture 6 facing the circuit board 2 in the initial position.The gap between the apertures 4 and 6 is thus freely accessible and is not limited by parts of the protruding shutter bodies 8 and 9. The circuit board 2 can be easily placed between the apertures 4 and 6 without colliding with the shutter bodies 8 and 9 or becoming jammed when inserted between them.

[0062] After adjusting the locking bodies8,9 into the working position as described in Fig. 3 As shown, the shutter bodies 8, 9 then protrude beyond the surfaces 12, 13 of the apertures 4, 6 and extend into the gap between the apertures 4, 6. The gap between the apertures 4, 6 and the gap 7, 7' between the apertures 4, 6 and the plate 2 are at least partially closed by the shutter bodies 8, 9 in the operating position.

[0063] The recesses 14,15 extend in the form of a groove-like recess over a certain length section of the corresponding aperture 4,6. The shutter bodies 8,9 have a length corresponding to the length of the groove and are held in the respective groove and guided slidably.

[0064] The closure bodies 8, 9 can be composed of several closure parts, for example to shield complex geometries. For this purpose, a large number of closure parts can be placed side by side or next to each other, together forming a closure body 8, 9.

[0065] The shielding device 1 is connected to a cooling circuit. This is not shown in the figures. The system pressure of the coolant supply is used to adjust the closure elements 8, 9 into their working position. A coolant flows through the shielding device 1 as soon as it is put into operation in an oven. The system pressure in the cooling circuit acts on the closure elements 8, 9, so that they are at least partially pushed out of the recess 14, 15 and adjusted into their working position. This allows for a particularly simple and cost-effective adjustment. The closure elements 8, 9 are returned to their initial position by a tension spring 16, 17, which is arranged in the recesses 14, 15 and pulls the closure elements back into the corresponding recess 14, 15 after the pressure in the cooling circuit drops.

[0066] The locking elements 8, 9 are designed as separate components and are detachably attached to the shielding device 1. This offers the advantage that the locking elements 8, 9 can be replaced by locking elements with different dimensions and that the shielding device 1 can be used for different circuit boards 2, for example, with different thicknesses.

[0067] The invention is not limited to the exemplary embodiments, but is variable in many ways within the scope of the disclosure.

[0068] All individual and combination features disclosed in the description and / or drawing are considered essential to the invention.

Claims

1. A shielding device (1) for covering at least a portion of a board (2) during tempering of the board (2) in a furnace, the shielding device (1) comprising a first shielding part (3) with at least one first aperture (4) and a second shielding part (5) arranged opposite thereto with at least one second aperture (6), an area of a board (2) heated to approximately austenization temperature being located between the apertures (4, 6) and being at least partially covered by the apertures (4, 6), the apertures (4, 6) being arranged opposite to one another with respect to the board (2), the covered portion of the board (2) being shielded by the shielding device (1) against further heat exposure, and the uncovered portion of the board (2) being maintained at or heated to the austenization temperature by the heat eposure, the first and second shielding parts (3, 5) being arranged at a distance from one another that is greater than the thickness of the board (2), and a gap (7, 7') being formed between the apertures (4, 6) and the board (2), characterized in that the shielding device (1) comprises at least two closure bodies (8, 9) that are adjustable or are adjusted transversely to the plane of the board, the closure bodies (8, 9) being spaced apart from one another and from the board (2) in an initial position and being brought closer together in an operating position, such that the closure bodies (8, 9) are positioned close to one another in a first subregion (10) of the board (2) while forming a gap and / or lie flush against one another at their ends in a second subregion (11) located adjacent to the board (2).

2. The shielding device of claim 1, characterized in that at least one first closure body (8) is attached to the first aperture (4) and at least one second closure body (9) is attached to the second aperture (6), the apertures (4, 6) and the closure bodies (8, 9) attached thereto being formed to be congruent with one another and being arranged to be aligned opposite to one another.

3. The shielding device of claim 1 or 2, characterized in that in the initial position, the first closure body (8) abuts with at least one end face against a first surface (12) of the first aperture (4) facing the board (2) or is set back behind this surface (12), and the second closure body (9) in the initial position has an end face that is at least flush with a second surface (13) of the second aperture (6) facing the board (2) or is set back behind this surface (13), the closure bodies (8, 9) protruding beyond the surfaces (12, 13) of the apertures (4, 6) in the operating position.

4. The shielding device of one of claims 1 to 3, characterized in that the closure bodies (8, 9) consist of several closure parts.

5. The shielding device of one of claims 1 to 4, characterized in that the shielding device (1) has a recess (14, 15) for each closure body (8, 9), in which the closure body (8, 9) is guided and held so as to be movable transversely to the board plane, the first closure body (8), when adjusted to the initial position, being completely located within the first recess (14) and, with its first surface facing the board (2) (12) of the aperture (4) being at least flush with or set back from the surface (12), the second closure body (9), when adjusted to the initial position, being completely located within the second recess (15) and, with the second surface (13) of the aperture (6) being at least flush with or set back from the surface (13), and the closure bodies (8, 9) protruding beyond the surfaces (12, 13) when adjusted to the operating position.

6. The shielding device of claim 5, characterized in that the shielding device (1) is connected to a cooling circuit, a coolant flowing through the shielding device (1) during heating in the furnace, and the closure bodies (8, 9) being adjusted to the operating position by a pressure set in the cooling circuit.

7. The shielding device of one of claims 1 to 6, characterized in that the closure bodies (8, 9) are returned to its initial position by a spring (16, 17).

8. The shielding device of one of claims 1 to 7, characterized in that the closure bodies (8, 9) have a U-shaped cross-section, the first closure body (8) having a long first leg (19) and a short first leg (20), and the second closure body (9) has a long second leg (21) and a short second leg (22), the closure bodies (8, 9) being closely approximated in the working position with the short legs (20, 22) to the first subregion (10) of the board (2) while forming a gap, and with the long legs (19, 21) lying against one another in the second subregion (11).

9. The shielding device of one of claims 1 to 8, characterized in that the first shielding part (3) and the second shielding part (5) have additional apertures (4') with closure bodies arranged thereat.

10. The shielding device of one of claims 1 to 9, characterized in that the shielding parts (3, 5) and the apertures (4, 6) are formed as a single piece.

11. The shielding device of one of claims 1 to 9, characterized in that the shielding parts (3, 5), the apertures (4, 6), and the closure bodies (8, 9) are constructed in multiple parts and are detachably connected to one another.

12. The shielding device of one of claims 1 to 11, characterized in that the shielding parts (3, 5) consist of multiple apertures that are assembled into a shielding part (3, 5).