Title of Invention

A CONTACT STRIP FOR MAKING ELECTRICAL CONTACT WITH METAL CONDUCTOR TRACKS RUNNING ON BOTH SIDES OF A PRINTED CIRCUIT BREAKER

Abstract

A contact strip (1) for making electrical contact with metal conductor tracks (21, 22) running on both sides of a printed circuit board (11), the contact strip (1) having a base body (2) having resilient contact elements (3, 3a, 3b, 3c), which are arranged opposite in the longitudinal direction of the base body (2) such that one narrow side of the printed circuit board (11) can be inserted between the mutually opposing contact elements (3, 3a, 3b, 3c) for the purpose of producing an electrical contact between the conductor tracks (21, 22) of said printed circuit board (11) and the contact elements (34, 3a, 3b, 3c), in each case mutually opposing contact elements (3a, 3b) being electrically insulated from one another within the base body (2), and each contact element (3, 3a, 3b, 3c) has at least two contact points (23) for the purpose of making electrical contact with in each case one conductor track (21, 22) of the printed circuit board (11) the based body (1) has a web (25), which is arranged in the longitudinal direction of the base body (1) between the mutually opposing contact elements (3, 3a, 3b, 3c) and in which a cutout (24) is provided which runs between the mutually opposing contact elements (3, 3a, 3b, 3c) and partially surrounds the narrow side of the printed circuit board (11) when said printed circuit board (11) is inserted.

Full Text

Description Contact strip for making electrical contact with metal conductor tracks running on both sides of a printed circuit board The invention relates to a contact strip for making electrical contact with metal conductor tracks running on both sides of a printed circuit board, the contact strip having a base body having resilient contact elements, which are arranged opposite in the longitudinal direction of the base body such that one end side of the printed circuit board can be inserted between the mutually opposing contact elements for the purpose of producing an electrical contact between the conductor tracks of said printed circuit board and the contact elements, in each case mutually opposing contact elements being electrically insulated from one another within the base body. Such contact strips are commonly known, for example, as so- called PCI plug connectors, which are arranged, for example, on motherboards of computers. Since the mentioned PCI plug connectors are only used for low currents and voltages, the individual contact elements of the PCI plug connectors can be arranged very close to one another without the dielectric strength of the plug connector being reduced. For example, the US patent application US 2002/0009929 has disclosed a contact strip for use in computer systems, for example for receiving processors or memory cards. Mutually opposing contact elements are electrically insulated from one another in the base body of the known contact strip. Owing to the fact that no problems as regards dielectric strength are to be expected in the voltage range in which the known contact strip is used, the mutually opposing contact elements can easily be arranged physically close to one another. Further contact strips for use at very low voltages are also known from the US patent specifications US 6,309,262, US 6,149,468, US 5,509,826 and US 5,848,920. Finally, a product catalog by the company Magnum (Cooper Bussmann) "Terminal Blocks Catalog, 2003", page 59, has disclosed a plug connector under the designation "Edge Connectors, Series 15104". However, with the known plug connector in each case opposing contact elements are electrically connected to one another and in each case adjacent contact elements have a greater distance from one another than the PCI plug connector mentioned initially, in order to ensure a relatively high dielectric strength of this plug connector. In order to make contact between a printed circuit board and metal conductor tracks arranged on its surface, such a printed circuit board is in each case inserted between the opposing contact elements and held in its position by the spring force of the individual contact elements. This embodiment has a comparatively high space requirement, in particular owing to the large distance between the adjacent contact elements. The invention is based on the object of specifying a contact strip of the type mentioned above which has a comparatively high dielectric strength with a relatively small physical size. This object is achieved according to the invention by the fact that a cutout is provided in the base body, runs in the longitudinal direction of the base body between the mutually opposing contact elements and partially surrounds the end side of the printed circuit board when said printed circuit board is inserted, such that there is an extended leakage path between mutually opposing contact elements. In this manner, the electrical leakage path between two opposing contact elements is increased in size when the printed circuit board is inserted by the fact that one end side of the printed circuit board is surrounded at least partially by the cutout; the leakage path is considerably extended by this labyrinth-like design. Furthermore, an inserted printed circuit board can be mechanically stabilized by this means. One advantageous design of this embodiment also provides for the base body to have a web, which is arranged in the longitudinal direction of the base body between the mutually opposing contact elements, and the cutout to be arranged in the web. Owing to the design of the web with the cutout, the leakage path between in each case two opposing contact elements can particularly advantageously be extended further, as a result of which the dielectric strength of the contact strip is increased "further. In order, in addition, to achieve increased current-carrying capacity, each contact element has at least two contact points for the purpose of making electrical contact with in each case one metal conductor track running on the printed circuit board. One advantageous embodiment of the contact strip according to the invention provides for the contact elements to have an undulating form in the region of their contact points. Owing to this design, it is particularly advantageously possible to achieve a situation in which the required number of contact points (for example two) is always connected to the corresponding conductor track of the printed circuit board, since a contact element, which has an undulating form in the region of its contact points, can be laid in a particularly flexible manner on the printed circuit board. One further advantageous embodiment of the contact strip according to the invention provides for the contact elements to be slotted at least once in their longitudinal direction in the region of their contact points. This particularly advantageously makes it possible to ensure that the contact elements with their contact points can be matched in a flexible manner to the position of the printed circuit board even if the printed circuit board is inserted at an angle or tilted. One further advantageous embodiment of the contact strip according to the invention provides for the contact elements to be prestressed in the direction of the respectively opposing contact elements such that, when there is no printed circuit board, an electrical contact is produced between such contact elements. This particularly advantageously makes it possible to achieve a situation in which in each case two opposing contact elements are electrically short-circuited when the printed circuit board is not inserted and there is thus no risk of an arc occurring between the contact elements which could damage the contact elements. In addition, it is thus advantageously possible to monitor the contact strip to establish whether a printed circuit board has been inserted. One further advantageous embodiment of the contact strip according to the invention also provides for the contact elements to be connected to in each case one electrical feed line using connections arranged in one plane on the base body, in each case the connections of adjacent contact elements being arranged such that they are offset with respect to one another in the plane. It is thus possible for the space required for the electrical connections to be kept as small as possible whilst maintaining the dielectric strength. As an alternative to this, provision may also be made for the contact elements to be connected to in each case one electrical feed line using connections arranged in at least two planes on the base body, in each case the connections of adjacent contact elements being arranged on different planes. Owing to the electrical connections arranged on at least two planes, in turn the space requirement can be substantially reduced with the same dielectric strength. In this case, provision may advantageously be made for the connections to be provided with clamping screws for the purpose of fixing electrical lines to be connected to be respective connections. In this manner, a particularly simple connection can be produced between the contact strip and further electrical lines via the respective connections of said contact strip. Brief description of the accompanying figures. In order to explain the invention in more detail, Figure 1 shows one exemplary embodiment of a contact strip according to the invention, Figure 2 shows a cross-sectional view of the contact strip illustrated in figure 1 with a printed circuit board inserted, Figure 3 shows an enlarged illustration of one exemplary embodiment of contact elements, Figure 4 shows a further exemplary embodiment of contact elements according to the invention, and Figure 5 shows a plan view of one exemplary embodiment of a contact strip according to the invention. Figure 1 shows a contact strip 1 having a base body 2. Contact elements 3, 3a, 3b, 3c which are resilient in the longitudinal direction of the base body 2 are arranged in two mutually opposing rows on the base body 2. The contact elements are made from an electrically conductive material and are designed to be resilient in the direction towards one another. In each case two mutually opposing contact elements (for example 3a and 3b) are electrically insulated from one another. The contact elements 3, 3a, 3b, 3c are surrounded by a box-shaped edging 4, as a result of which mechanical damage to the contact elements, for example during storage and transportation and uncareful handling of the contact strip, is prevented. Electrical line guides (not illustrated in figure 1) are located within the base body 2 and connect the individual contact elements 3, 3a, 3b, 3c in each case to one connection 5 on the outside of the base body. In order to make contact with conductor tracks provided on a printed circuit board, the end side of this printed circuit board is inserted from above between the mutually opposing rows of contact elements 3, 3a, 3b, 3c. Longitudinal guides 6 provided in the edging 4 simplify precise placement of the printed circuit board when it is inserted between the contact elements 3, 3a, 3b, 3c and mechanically stabilize the printed circuit board in its position when it is inserted. A cross-sectional view of the contact strip shown in figure 1 is illustrated in figure 2 with a printed circuit board inserted. In this case, the same references have been used for mutually corresponding components as those in figure 1. Figure 2 clearly shows the position of an inserted printed circuit board 11 between the two rows of contact elements, of which in this case the contact elements 3a and 3b (cf. figure 1) are illustrated by way of example. In addition, figure 2 shows a so-called "two-story" design of the contact strip having connections lying one on top of the other on two planes (for example 5a and 5c). By way of example, an electrical link 12 is indicated schematically between the contact element 3b and an electrical connection 5b. Such an electrical link is also present, for example, between the contact element 3a and the electrical connection 5a. A further contact element 3c (cf. figure 1), which is positioned in front of or behind the contact element 3a in the longitudinal direction of the contact strip, would be connected on the second connection plane, for example, to the electrical connection 5c. In such a way, contact elements (for example 3a and 3c) , which are positioned adjacent to one another, can always be connected to electrical connections on respectively different planes. Accordingly, a further contact element, following the contact element 3c, would in turn be connected to an electrical connection on the upper connection plane in a similar manner to the electrical contact element 3a. In this manner, despite the electrical connections which, for practical reasons, generally need to be designed to be very large and in which, for example cable shoes need to be inserted, a relatively space-saving design can be achieved in the-longitudinal direction of the contact strip. Figure 2 also shows a schematic illustration of a clamping screw 13, as an example of the electrical connection 5b, with the aid of which clamping screw 13 it is possible to fixedly clamp, for example, a cable shoe, which is inserted into the electrical connection 5b. Such clamping screws can also be used in the other electrical connections of the contact strip. In addition to the two-story design of the contact strip shown in figure 2, it is naturally also conceivable for there to be any desired higher number of connection planes. Figure 3 shows the contact elements 3a and 3b in a very enlarged view. The printed circuit board 11 (cf. figure 2) is inserted between the opposing contact elements 3a, 3b. The printed circuit board 11 is provided with metal conductor tracks 21 and 22, which in each case represent separate line guides on the printed circuit board. Consequently, the conductor tracks 21 and 22 are not necessarily at the same voltage potential and do not carry the same currents. When the printed circuit board 11 is inserted, there is an electrical contact between the contact element 3a and the conductor track 21, on the one hand, and the contact element 3b and the conductor track 22, on the other hand. Since the conductor tracks 21, 22 represent current paths which are separate from one another, the contact elements 3a and 3b also need to be electrically insulated from one another. As a result of the fact that in each case two mutually opposing contact elements 3a and 3b of the contact strip make contact with in each case different conductor tracks and are electrically insulated .from one another, the longitudinal extent of the contact strip can be reduced, for example, by a factor of 2 with the same number of contact-connected conductor tracks in comparison with a design in which the conductor tracks 21 and 22 would be at the same potential, and thus no electrical insulation between the contact elements 3a and 3b is provided. In order, however, to be able to carry currents which are as high as possible (for example in the range from approximately 10 A) without cold- welding occurring at a contact point 23 between a contact element (for example 3a) and the corresponding conductor track (for example 21) on the printed circuit board 11 owing to the high amount of heat developed, the contact elements 3a and 3b are designed such that they enter into an electrical connection with the conductor track 21 or 22 on the printed circuit board 11 in each case at at least two separate contact points. For this purpose, the contact elements 3a and 3b shown in figure 3 advantageously have an undulating form in the region of their contact points 23. In addition, this undulating design also ensures that the contact elements 3a, 3b can be matched in a flexible manner to the conductor tracks 21, 22, for example even when the printed circuit board 11 has a slightly inclined position. Owing to the embodiment with at least two contact points 23, which are separate from one another, per contact element 3a or 3b, it is possible, on the one hand, to achieve a situation in which, per contact point 23, approximately only half of the current flowing between a conductor track 21 or 22 and a contact element 3a or 3b needs to be conducted and thus less heat is developed at the contact points 23. On the other hand, owing to the respectively separated position of the contact points 23, a measured heat dissipation also takes place to the environment of each contact point 23. The number of contact points 23 per contact element 3a, 3b can be increased as desired in order to further improve the abovementioned effects. In- order to be able to use an embodiment with respectively electrically insulated opposing contact elements 3a, 3b even in the case of relatively high voltages, the distance between in each case any two points of the contact elements 3a, 3b in relation to one another needs to be kept as large as possible in order that no voltage flashovers can occur between the contact elements 3a, 3b, as a result of which both the contact elements 3a, 3b and electronic components on the printed circuit board, which may be connected to the conductor tracks of the printed circuit board, could be destroyed. In order to further increase the so-called leakage paths, i.e. the air line between two such desired points of the contact elements 3a and 3b, a cutout 24 is provided on the base body 2 of the printed circuit board, as shown in figure 3, the end 26 of the printed circuit board 11 penetrating a little way, so to speak, into said cutout 24. The leakage paths are particularly advantageously extended when this cutout 24 runs on a web 25 arranged on the base body. In such a case, leakage paths which are as long as possible are produced between any two desired points of the contact elements 3a and 3b by a labyrinth-like design. In order, in addition, to prevent voltage flashovers between the individual contact elements 3a and 3b even when the printed circuit board 11 is not inserted or in the case in which the printed circuit board 11 is withdrawn from the contact strip, said contact elements 3a and 3b can be (mechanically) prestressed with respect to one another, in the directions indicated by arrows Fl and F2, in each case so severely that the contact elements 3a and 3b move towards one another, owing to the resilient effect, when the printed circuit board 11 is not inserted or when it is withdrawn to such an extent that an electrical contact between its contact points 23 is produced. It is thus possible, for example, for the contact strip to be monitored to ascertain whether a printed circuit board 11 has been inserted or not. For this purpose, namely only one device for short-circuit monitoring needs to be provided between the contact elements 3a and 3b, which device emits a signal if there is a short circuit between the contact elements 3a and 3b. In addition, it can clearly be seen in figure 3 that the conductor tracks 21 and 22 are set back slightly from the end 26 of the printed circuit board in order to further extend the leakage path required for this embodiment as regards the dielectric strength of the arrangement. Figure 4 shows one possible embodiment of a contact element. In this case, the contact element 3b (cf. figure 3) is illustrated by way of example. In addition to a side view A, a front view B of the contact element 3b is shown. It can clearly be seen that the contact element 3b has a slot 33 between two lateral arms 31 and 32, that is to say it is slotted once. Owing to this embodiment, the individual contact elements (for example 3b) can also be matched in a more flexible manner to a printed circuit board which has been inserted into the contact strip at a slight angle or tilted. In addition, the individual contact points 23 are divided up into at least two contact point pairs 23a and 23b per contact point 23 owing to a slotted design, and said contact point pairs 23a and 23b are separated from one another by the slot 33. Further improved heat dissipation can thus be achieved per contact point 23a or 23b. Finally, figure 5 shows a plan view of a contact strip 1, in which, in turn, the same components are identified by the same references as in the previous figures. With reference to figure 5, a further possible embodiment of the electrical connections 5 is shown. In addition to the two-story or multi- story embodiment explained in figure 2, only one connection plane per contact strip 1 can also be used, in which in each case the electrical connections, for example 41 and 42, of adjacent contact elements, for example 43 and 44, are arranged offset with respect to one another in each case within the same plane. This embodiment also makes it possible for the required distance between the two mutually adjacent electrical connections, for example 41 and 42, to be achieved such that the required dielectric strength is provided. Contact strips of the type described can be used, for example, in electrical devices, such as electrical protection devices or control devices, where they can easily be connected to a housing of the corresponding electrical device owing to their relatively stable embodiment. Printed circuit boards having corresponding circuits can in each case be inserted into such a contact strip. In this manner, such an electrical device can be fitted with printed circuit boards in a very flexible manner. Owing to the embodiment explained, in particular with the respectively opposing, electrically insulated contact elements, the longitudinal extent of such a contact strip can be markedly reduced whilst maintaining the same number of contact-connected conductor tracks on the printed circuit board. This is particularly important since restrictions are often prescribed in the mentioned electrical devices in terms of the physical extent, in particular the width and height, of the electrical devices. WE CLAIM : 1. A contact strip (1) for making electrical contact with metal conductor tracks (21, 22) running on both sides of a printed circuit board (11), the contact strip (1) having a base body (2) having resilient contact elements (3, 3a, 3b, 3c), which are arranged opposite in the longitudinal direction of the base body (2) such.that one narrow side of the printed circuit board (11) can be inserted between the mutually opposing contact elements (3, 3a, 3b, 3c) for the purpose of producing an electrical contact between the conductor tracks (21, 22) of said printed circuit board (11) and the contact elements (34, 3a, 3b, 3c), in each case mutually opposing contact elements (3a, 3b) being electrically insulated from one another within the base body (2), and each contact element (3, 3a, 3b, 3c) has at least two contact points (23) for the purpose of making electrical contact with in each case one conductor track (21, 22) of the printed circuit board (11). characterized in that the based body (1) has a web (25), which is arranged in the longitudinal direction of the base body (1) between the mutually opposing contact elements (3, 3a, 3b, 3c) and in which a cutout (24) is provided which runs between the mutually opposing contact elements (3, 3a, 3b, 3c) and partially surrounds the narrow side of the printed circuit board (11) when said printed circuit board (11) is inserted. 2. The contact strip (1) as claimed in claim 1, wherein the contact elements (3, 3a, 3b, 3c) have an undulating form in the region of their contact points (23). 3. The contact strip (1) as claimed in Claim 1, wherein the contact elements (3, 3a, 3b, 3c) are slotted at least once in their longitudinal direction in the region of their contact points (23). 4. The contact strip (1) as claimed in one of the preceding claims, wherein the contact elements (3, 3a, 3b, 3c) are prestressed in the direction of the respectively opposing contact elements such that, when there is no printed circuit board (11), an electrical contact is produced between such contact elements. 5. The contact strip (1) as claimed in one of the preceding claims, wherein the contact elements (3, 3a, 3b, 3c) are connected to in each case one electrical feed line (12) using connections (41, 42) arranged in one plane on the base body (2), in each case the connections (41, 42) of adjacent contact elements (43, 44) being arranged such that they are offset with respect to one another in the plane. 6. The contact strip (1) as claimed in one of claims 1 to 4, wherein the contact elements (3, 3a, 3b, 3c) are connected to in each case one electrical feed line (12) using connections (5, 5a, 5b, 5c) arranged in at least two planes on the base body (2), in each case the connections (5a, 5c) of adjacent contact elements (3a, 3c) being arranged on different planes. 7. The contact strip (1) as claimed in either of claims 5 and 6, wherein the connections (5, 5a, 5b, 5c) are provided with clamping screws (13) for the purpose of fixing electrical lines to be connected to the respective connections (5, 5a, 5b, 5c).

Documents:

02255-kolnp-2005-abstract.pdf

02255-kolnp-2005-claims.pdf

02255-kolnp-2005-description complete.pdf

02255-kolnp-2005-drawings.pdf

02255-kolnp-2005-form 1.pdf

02255-kolnp-2005-form 2.pdf

02255-kolnp-2005-form 3.pdf

02255-kolnp-2005-form 5.pdf

02255-kolnp-2005-international publication.pdf

2255-KOLNP-2005-ABSTRACT 1.1.pdf

2255-KOLNP-2005-CANCELLED PAGES.pdf

2255-KOLNP-2005-CLAIMS 1.1.pdf

2255-kolnp-2005-correspondence.pdf

2255-kolnp-2005-correspondence1.1.pdf

2255-KOLNP-2005-DESCRIPTION (COMPLETE) 1.1.pdf

2255-kolnp-2005-examination report.pdf

2255-KOLNP-2005-FORM 1.1.1.pdf

2255-kolnp-2005-form 18.1.pdf

2255-kolnp-2005-form 18.pdf

2255-KOLNP-2005-FORM 2.1.1.pdf

2255-kolnp-2005-form 3.pdf

2255-kolnp-2005-form 5.pdf

2255-KOLNP-2005-FORM-27-1.1.pdf

2255-KOLNP-2005-FORM-27.pdf

2255-kolnp-2005-gpa.pdf

2255-kolnp-2005-gpa1.1.pdf

2255-kolnp-2005-granted claims.pdf

2255-kolnp-2005-granted-abstract.pdf

2255-kolnp-2005-granted-description (complete).pdf

2255-kolnp-2005-granted-drawings.pdf

2255-kolnp-2005-granted-form 1.pdf

2255-kolnp-2005-granted-form 2.pdf

2255-kolnp-2005-granted-specification.pdf

2255-kolnp-2005-international search report.pdf

2255-KOLNP-2005-OTHERS.pdf

2255-kolnp-2005-others1.1.pdf

2255-KOLNP-2005-PA.pdf

2255-kolnp-2005-pct priority document notification.pdf

2255-kolnp-2005-pct request form.pdf

2255-KOLNP-2005-PETITION UNDER RULE 137.pdf

2255-KOLNP-2005-REPLY TO EXAMINATION REPORT.pdf

2255-kolnp-2005-reply to examination report1.1.pdf

2255-kolnp-2005-translated copy of priority document.pdf

2255-kolnp-2005-translated copy of priority document1.1.pdf

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