The patent's inventor is Rummler, Maik (Baunach, DE).
This patent was filed on
From the background information supplied by the inventors, news correspondents obtained the following quote: "Field of the Invention
"The invention relates to a mounting method for mounting a circuit board in a housing. The invention also relates to a mounting tool for carrying out the method. In the application that is primarily targeted, the housing is an electronics module in a motor vehicle, in particular an electrical window lifter.
"A circuit board conventionally comprises an insulating supporting board (also referred to as a 'substrate'), which is provided with electrical conductor tracks and also electrical or electronic components. In the case of circuit boards such as are used particularly for electronics modules for motor vehicles, the conductor tracks are often printed onto the substrate from electrically conductive material. These are also referred to as 'PCBs' (i.e., printed circuit boards).
"In a production process that is particularly advantageous for automated production in particular, circuit boards are press-contacted with electrical terminal conductors when they are inserted into the housing. This involves press-in pins or 'press-fit pins' (also referred to hereafter as press-contact pins) of the housing being pressed into corresponding metalized contact holes of the circuit board, whereby a solder-free electrical connection is established. In order that such press-contact connections are however closed reliably and durably, very precise positioning of the circuit board with respect to the housing is necessary when establishing such a press-contact connection. Even minor maladjustment of the press-contact pins with respect to the contact holes may lead to inadmissible widening of the contact holes, bending or breaking of individual press-contact pins or other production defects.
"For easy and precise adjustment of the circuit board during insertion, protruding pilot pins onto which the circuit board is fitted with corresponding centering holes (hereafter also referred to as 'pilot holes') are often provided in a circuit board holder of the housing. The pilot pins generally taper in the region of their free ends, in order to facilitate the fitting on of the circuit board. As a result of the structural design, the circuit board to be inserted is still guided with a certain amount of play on the pilot pins because of the tapering when it comes into contact with the tips of the press-contact pins during the inserting operation. The reason for this is in particular that the pilot pins can only protrude beyond the press-contact pins to a small extent because of the often very flat construction of the housing. As a result, the circuit board often initially rests on the tips of the press-contact pins before the press-contact pins 'find' the associated contact holes and the pressing-on operation can be concluded. This may disadvantageously have the effect that the press-contact pins damage the metalized area around the contact holes, which may lead to material abrasion or uplift. Damage to the metal layer in the contact hole may--in the case of a multilayered circuit board--particularly lead to undesired delamination."
Supplementing the background information on this patent, VerticalNews reporters also obtained the inventor's summary information for this patent: "It is accordingly an object of the invention to provide a mounting method for mounting a circuit board in a housing which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which makes it possible to position the circuit board particularly precisely in a housing by simple means. It is a further object of the invention to provide a (mounting) tool with which the mounting method can be carried out particularly well.
"With the foregoing and other objects in view there is provided, in accordance with the invention, a method of mounting a circuit board in a housing, the method which comprises:
"providing a circuit board with at least one pilot hole and placing the circuit board onto a mounting tool having a number of pilot pins, wherein each of the number of pilot pins protrudes through and projects beyond the circuit board on a side facing away from the mounting tool;
"displacing the mounting tool toward a circuit board holder of the housing to cause the pilot pins or at least one of the pilot pins to engage in a corresponding centering hole of the circuit board holder;
"fixing the circuit board in the housing; and
"withdrawing the mounting tool by detaching each pilot pin from the corresponding pilot hole, with the circuit board remaining in the circuit board holder.
"Preferably, the at least one pilot hole is one of a plurality of pilot holes formed in the circuit board and the mounting tool is provided with a plurality of pilot pins disposed at locations corresponding to locations of the pilot hoes of the circuit board.
"With the above and other objects in view there is provided, in accordance with the invention, a mounting tool for mounting a circuit board on a circuit board holder in a housing, the mounting tool being configured to carry out the above-summarized mounting method. The novel mounting tool comprising:
"a tool upper plate having associated therewith one or more pilot pins, and a tool lower plate having a housing holder for positioning the housing;
"wherein the circuit board can be placed with the or each pilot hole provided therein onto the respectively corresponding pilot pin, and
"wherein the tool upper plate is displaceable toward the lower plate to thereby cause the circuit board to be inserted into the circuit board holder of the housing.
"According to the invention, the housing is not provided with pilot pins--or at least not only the housing is provided with pilot pins--for the circuit board to be inserted therein. Rather, according to the invention the (mounting) tool used for mounting the circuit board is (at least also) provided with at least one pilot pin, but preferably a number of pilot pins, which can be inserted into a number of corresponding pilot holes of the circuit board, corresponding in number to the pilot pins. According to the method, the circuit board provided with the at least one pilot hole is first placed onto the or each corresponding pilot pin of the tool. The length of the or each pilot pin is in this case dimensioned such that the or each pilot pin protrudes beyond the fitted-on circuit board on the side facing away from the tool. Preferably, at least two pilot pins and a corresponding number of corresponding pilot holes are provided in order to adjust the circuit board on the tool securely in terms of turning and tilting.
"Expediently, the or each pilot pin is aligned with respect to its longitudinal direction (also: axial direction) substantially perpendicularly to the pushed-on circuit board and is dimensioned in such a way that it protrudes beyond the pushed-on circuit board by a multiple of the circuit board thickness, for example by at least five times.
"After the fitting of the circuit board onto the tool, the latter is displaced toward a circuit board holder of the housing, so that at least one pilot pin of the tool engages in a corresponding centering hole (also: centering bore) of the circuit board holder. The tool is thereby advanced toward the circuit board holder until the circuit board has reached its intended mounting position in the circuit board holder.
"In the same way as the corresponding pilot hole and the possibly associated centering hole, the or each pilot pin preferably has a round cross section. However, the pilot pin, the pilot hole and the centering hole may also be provided with a non-round cross section, made to match one another. This is particularly advisable for securing the circuit board against twisting with respect to the tool whenever only one pilot pin, and correspondingly only one pilot hole and one centering hole, are provided.
"The circuit board holder is preferably formed as a concave, particularly pan- or shell-like depression of the housing, which encloses the inserted circuit board from a number of sides. The circuit board holder may, however, in principle also be a planar housing area onto which the circuit board is placed in a freestanding manner. In this case, the circuit board holder is also referred to as a circuit board rest.
"During or after the advancement of the tool, the circuit board is fixed in the housing. Subsequently, the tool is withdrawn, the or each pilot pin being pulled out from the corresponding pilot hole of the circuit board, and the circuit board remaining in the circuit board holder. The fixing of the circuit board in the housing may in principle take place here by any desired fastening method, such as for example by clamping, interlocking, welding or else adhesively bonding the circuit board in the housing.
"A major advantage of the mounting principle according to the invention is that the or each pilot pin arranged on the tool can be designed largely independently of the geometry and other structural requirements of the housing. In particular, the or each pilot pin may in principle be of any length, whereby play-free guidance of the pilot pin in the or each centering hole of the housing can be realized comparatively easily. In particular, sufficiently long dimensioning of the or each pilot pin advantageously makes it possible that it already engages in the corresponding centering hole with little play manner before the circuit board comes into contact with the circuit board holder. Consequently, damage to the circuit board or the components located on it by component parts of the circuit board holder can be reliably avoided.
"In a particularly preferred embodiment of the mounting method, during the introduction of the circuit board into the circuit board holder of the housing, a press-contact connection is closed in that a press-contact pin of an electrical terminal conductor that is located in the housing penetrates into a corresponding contact hole of the circuit board, so that the circuit board material in the area around the contact hole is deformed and, as a result, a force closure or friction fit is formed between the press-contact pin and the circuit board. In a way that is in itself customary, the press-contact pin is in this case pressed into the contact opening of the circuit board. In an equivalent way, the or each contact pin may also be fastened on the circuit board and interact with a contact hole in the housing to establish the press-contact connection. In principle, it would also be possible to provide both contact pins and corresponding contact holes respectively on both the circuit board and the housing.
"In principle, furthermore, in addition to the press-contact connection, further means for fixing the circuit board to the housing may be provided, for example engaging lugs at the edge of the circuit board holder, which engage with a form fit around the inserted circuit board. In a preferred embodiment of the invention, however, the circuit board is fixed in the housing or in the circuit board holder exclusively or at least predominantly by the press-contact connection. The term 'predominantly' should be understood here as meaning that the press-contact connection has a greater tear-off resistance than all the further means there may possibly be for fixing the circuit board in the circuit board holder.
"In a particularly expedient embodiment of the invention, when the circuit board is placed onto the tool, the or each pilot pin forms with the pilot holes of the circuit board a--nondestructively releasable--force closure or form fit, which holds the circuit board captively on the tool, at least counter to its own weight. In particular, at least two pilot pins are for this purpose dimensioned with respect to the corresponding pilot holes in such a way that they are elastically deformed slightly during the placing on of the circuit board.
"In an expedient development of this variant of the invention, it is provided that, after the insertion and fixing of the circuit board in the circuit board holder, the captive securement of the circuit board on the tool that is brought about by the or each pilot pin is forcibly released, or at least forcibly loosened, by means of a detaching mechanism, which can be moved with respect to the or each pilot pin.
"The forcible release or loosening of the force closure or form fit that is formed between the or each pilot pin and the circuit board has the effect that the stress that would act on the circuit board during the withdrawal of the tool on account of the force closure or form fit of the circuit board on the tool on the one hand and on account of the fixing of the circuit board in the circuit board holder on the other hand is suppressed or at least reduced. In other words, the tool can therefore be withdrawn without the circuit board being stressed to a considerable extent between the tool and the housing. Consequently, the mounting method treats the circuit board gently, and the risk of production defects is reduced.
"In a particularly simple embodiment, the detaching mechanism is formed by an ejector, in particular in the form of a ram, the position of which is initially kept unchanged during the withdrawal of the tool, so that the ejector holds the circuit board in the circuit board holder.
"As an alternative or in addition to such an ejector, the detaching mechanism may also comprise means which deform, in particular laterally bend or narrow, the or each pilot pin during the withdrawal of the tool.
"The mounting tool provided for carrying out the mounting method according to the invention particularly comprises a (tool) upper plate, on which the or each pilot pin is directly or indirectly provided, and a (tool) lower plate, which has a housing holder for holding the housing. In this case, the circuit board can be placed as intended onto the or each pilot pin. By displacing the upper plate toward the lower plate, the circuit board can be inserted into the housing or into a circuit board holder of the housing as provided by the mounting method according to the invention.
"In a preferred embodiment of the mounting tool, the or each pilot pin runs conically, at least in a portion of the free end, and consequently tapers, advantageously facilitating on the one hand the fitting of the circuit board onto the or each pilot pin but on the other hand also the centering of the pilot pin in the at least one centering hole of the housing.
"For further assisting good positioning of the circuit board in the housing, the upper plate is preferably linearly guided with respect to the lower plate in a direction of advancement. In an embodiment that is expedient and can be easily realized, for this purpose the mounting tool has at least one guiding bolt, preferably at least two guiding bolts, which in interaction with associated guiding grooves or bores align the upper plate with respect to the lower plate transversely to the direction of advancement with little play and guide it during the advancement.
"For low-stress forcible detachment of the circuit board from the upper plate of the tool, in an expedient design the tool has an ejector of the type and operating mode described above, in particular in the form of at least one ram that can be displaced in relation to the upper plate of the tool in the direction of advancement.
"In an application that is primarily pursued, the mounting method according to the invention and/or the associated mounting tool are used for circuit board mounting in the case of an electronic vehicle module, particularly an electrical window lifter.
"Other features which are considered as characteristic for the invention are set forth in the appended claims.
"Although the invention is illustrated and described herein as embodied in Mounting method for mounting a circuit board in a housing and associated mounting tool, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
"The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings."
For the URL and additional information on this patent, see: Rummler, Maik. Mounting Method for Mounting a Circuit Board in a Housing and Associated Mounting Tool. U.S. Patent Number 8782881, filed
Keywords for this news article include: Electronics, Circuit Board,
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