Title of Invention

SPRING-LOADED CLAMPED CONNECTION FOR AN ELECTRICAL CONDUCTOR .

Abstract

The invention relates to a spring-loaded clamped connection for the connection of an electrical conductor, which in conformance to the class has a busbar piece with a rectangular material rail, into which the clamping side end of a leaf spring dips in such a way that the clamping side end with a collar inner wall surface of the material rail forms a contact point for the electrical conductor. It is suggested that for the collar inner wall surface of the material rail a new formation is used with a cross-edge/lateral edge and to provide the contact point for the electrical conductor in the depth of the material rail, through which simultaneously a metal-jacketed conductor trap is formed.

Full Text

The invention relates to an electrical spring-loaded clamped connection. An important generic feature of such spring-loaded clamped connections is a rectangular material rail with a curved bottom through the busbar piece made of a flat material. The above mentioned rail serves as an opening for the insertion of a conductor and has a hollow collar extending in the direction of the conductor insertion, so that a contact point for an electrical conductor is formed between the inner wall surface of the collar and an end of a leaf spring extending into the material rail (see DE 28 25 291 C2). Such busbar pieces can be provided with one, but also with many material rails, which are preferably arranged in a line to obtain a possibly narrow structural form of the busbar piece (e.g. in the shape of a punched out material strip), as it is required, for example for the series terminal arrangements. In the region of the material rails, such particularly narrow busbar pieces have merely narrow edge-shoulders extending in the busbar direction, the current conduction cross-sections of which as a rule are not sufficient. This disadvantage is compensated by the collar of the material rails, the collar cross-sections of which are simultaneously also current conducting cross-sections, so that the cross- sections of the edge shoulders together with the collar cross-sections form a sufficiently large current conducting cross-section in the direction of the busbar piece. However, the known spring-loaded clamped connections of this type have the disadvantage that the current transition values between the inner wall surface of the collar and the clamped electrical conductor are very much insufficient. Practical tests to solve this problem by increasing the clamping forces of the leaf spring were unsatisfactory, because higher clamping forces have an adverse effect on the inserting forces, which are to be applied manually for the clamping of the electrical conductor. Therefore the task of the invention is to retain the advantages of the generic feature of a spring-loaded clamped connection having in its busbar, a material rail with a collar, but at the same time to improve the current transition values in the contact point without increasing the conductor inserting forces or deteriorating the conductor inserting action in another way. As per the invention, this task is solved such that a cross-edge projecting towards the electrical conductor and extending across the direction of conductor insertion is provided at the collar inner wall surface, which with the clamping side end of a leaf spring forms the contact point, and that the clamping side of the leaf spring is dimensioned and shaped in such a way that the end-side clamping edge of the clamping side end in the position of the clamping of the electrical conductor more or less faces the cross-edge present at the inner wall surface of the collar. The cross-edge can be provided at different positions of the arrangement along the stretch of the collar extending in the direction of conductor insertion, however a very advantageous and production-related extremely cost-effective embodiment provides for, that the cross-edge is formed by the bottom edge - in direction of conductor insertion - of the collar of the material rail. For this purpose, the aforesaid bottom edge is advanced towards the electrical conductor to be clamped. This can be effected either with an inclined arrangement of the busbar piece on the whole or for example, by upsetting, pressing or forging the assigned collar wall region. The other collar wall regions which contribute nothing to the formation of the contact point, are not affected by this measure, however can also be deformed, if this could facilitate the production-related procedures in the manufacture and shaping of the material rail and collar. As per the invention, the solution is new for spring-loaded clamped connections, which in their busbar piece have a material rail with a collar, and considerably improves the current conduction and contact security in the contact point. This results firstly from the advantage of the formation of a contact point, which appears as intersecting point between the electrical conductor and the projecting cross-edge at the collar inner wall surface and which geometrically minimises the contact bearing surface between the electrical conductor and the collar of the material rail to a smaller defined contact bearing surface; secondly in combination with a maximum possible application of contact forces, which results from the fact that the clamping side of the clamping spring is dimensioned and shaped in such a way that the end-side clamping edge of the clamping side end in the position of the clamping of the electrical conductor has an almost direct effect on the geometrically minimised bearing surface of the contact, as the clamping edge of the clamping side end more or less faces the cross-edge formed at the collar inner wall surface. A high specific contact pressure in the bearing surface of the contact, which improves the current conductions and in addition, a guaranteed gastight contact results from this. The positioning of the clamping side end of the leaf spring, more or less facing the cross-edge at the collar inner wall surface, has the additional advantage, that none of the overturning moment resulting from the clamping force of the leaf spring will act on the clamped electrical conductor. If preferably the "projecting cross-edge" at the collar inner wall surface is formed by the "advanced bottom edge" of the collar of the material rail, then the contact point for electrical conductor shifts to the maximum extent into the depth of the material rail, from which additional significant advantages result. Thus, in a preferred embodiment, the region of the collar inner wall surface which in the direction of the conductor insertion is extended in front of the contact point, can be designed as relatively large inclined planes and with smooth transitions formed without jerk or jolt (preferably flat shaped), which during the insertion action leads the forward end of the electrical conductor smoothly and softly (i.e. without "hard" jerky transitions), so that the conductor inserting forces are reduced and possibly existing surface coatings, such as for example, a tin coating on the collar inner wall surface and in the region of the contact point, are protected against undesired abrasion. The task, to provide a conductor trap for spring-loaded clamping connections of this type, so that even multiwire electrical conductors can be inserted without any problem, without their fanning out and/or deflecting in some other way. This task is solved thereby, that for uncoated and closed contact point, an end-side section of the clamping side of the leaf spring is located within the contour of the material rail (i.e. is positioned in the depth of the material rail), in fact with a flat extension of the section which is equal to or greater than the nominal cross-section of the conductor to be clamped, in such a way that the ring-shaped, closed collar inner wall surfaces with the end-side section of the clamping side form an all-sided metal enclosed conductor trap for the forward end of the electrical conductor which is to be inserted. For the geometrical shape of the aforementioned conductor trap, it is advantageous to provide the end-side section of the clamping side of the leaf spring to be, as far as possible, flat within the collar contour, so that a possibly blunt seating of the front face of the clamping side end against the surface of the electrical conductor results, whereby when conductor pull-out forces occur, a sharp-edged clamping of the conductor is prevented and even highly sensitive fine wire conductors can be clamped without any damages. The conductor trap as such bundles multiwire conductors and has for all types of electrical conductors. The advantage that in a plug-in connection, the front end of the electrical conductor is to be inserted first, without applying any force, into the conductor trap and as a result of this is fixed against deflecting movements, before the opening of the contact point is initiated by means of a manually applied axial force on the conductor. The task, of being able to open the contact point in spring-loaded clamped connections of this type even when the contact point is located in the depth of the material rail, is to be solved. In case of spring-loaded clamped connections of the generic type, it is always a problem, for opening the contact point, to be able to push back the clamping side of the leaf spring, by applying a force against its spring resistance, so far that the contact point is optimally, i.e. fully open. This is applicable especially when because of a compact wiring system the tool (screwdriver) can be pushed forward only axially for opening the contact point. This problem is solved with that a middle section of the clamping side of the leaf spring outside the contour of the material rail has a protrusion (convexity) in the direction of spring clamping force of the clamping side, to such an extent that a spinning tool placed on this protrusion and mainly perpendicular to the surface of the busbar piece pushes back the clamping side up to a position, in which the contact point is fully open. Basically it is to be noted that a spring-loaded clamped connection conceived as per the principle of the invention can be realised in the model with a leaf spring - in mirror image design - for two material rails arranged adjoining one another in a busbar piece (refer to the type in DE 28 25 291 C2) as well in a model with a leaf spring, which has a locating or holding side, which can be fixed to the busbar piece in any way (e.g. by riveting or pressing), or a type is selected, in which the spring leaf is bent U-shaped and has a locating side at its end which is opposite to the clamping side, which along with the clamping side of the leaf spring extends into the same material rail of the busbar piece and which rests against the collar inner wall surface, which faces the collar inner wall surface which forms the contact point. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS In the following an embodiment of the invention is described in detail with help of the drawings. They show: Figure 1 and Figure 2a + 2b a spring-loaded clamped connection as per the invention Figure 3,4, 5 functional sequence of the spring-loaded clamped connection as per Figure 1, when used as a plug-in connection Figure 6 the spring-loaded clamped connection as per Figure 1 upon opening the contact point. According to Figure 1 there is provided a busbar piece 10 with a rectangular material rail 11, which can be seen in detail in the illustration in Figure 2a (longitudinal section) and Figure 2b (top view). The piece of the busbar 10 described in Figure 2a and 2b also shows that any number of such material rails can be positioned adjoining one another in a row. For the busbar, the shape of a narrow material strip can be selected, which in the region of the material rails has edge shoulders 12 having a very small width. The material rail 11 has a ring-shaped closed collar 13 - drawn (by plunging) from the top surface of the busbar piece - with collar inner walls 14 and 15. The transitions from the top surface of the busbar piece to the collar inner wall surfaces can be designed as leading-in rounding or leading-in inclinations 16 and 17. A mainly U-shaped bent leaf spring is placed in the material rail, which in the given embodiment rests with its rear bend of the spring on a plastic mandrel 18 of an housing made of insulating material in which such spring-loaded clamped connections are mounted, and is thus additionally fixed in its position. The width of the leaf spring corresponds at least in the region of the locating side 19 extending into the material rail and of the clamping side 20 dipping into the material rail, to the width of the rectangular rail. Instead of the additional position-fixing by means of the plastic mandrel 18, for example, other means such as the locating shoulders of the locating side resting on the top side of the busbar piece and/or, for example, a press fit of the locating side in the material rail can be used for the additional position-fixing of the leaf spring. However, such kind of an additional position-fixing of the leaf spring can be entirely dropped in many applications, because the pre-tension of the U-shaped leaf spring ensures also a self- holding of the leaf spring in the material rail. For uncoated and closed contact point, the end-side clamping edge 21 of the clamping side 20 rests on the collar inner wall surface 15 and is thus held in the material rail by stop lug fixing. As per the principle of the invention, a cross-edge projecting towards the electrical conductor, i.e. in the direction of the center of the material rail and extending across the direction of conductor insertion through the material rail is formed on the collar inner wall surface 15. In the embodiment described, the aforesaid cross-edge is formed by the bottom edge 22 of the collar 13, which for this purpose is moved forward in the direction of the center of the material rail. Further, as per the principle of the invention, the clamping side 20 of the leaf spring is dimensioned and shaped in such a way, that in the position of the clamping of the electrical conductor 23 (refer Figure 5) it dips maximum into the depth of the material rail, whereby in the clamping of the electrical conductor its end-side clamping edge 21 more or less faces the bottom edge 22 of the collar, so that the electrical conductor is clamped free of overturning moment in the contact point 21/22. The embodiment described realises the formation of a so-called conductor trap 24 also (refer Figure 3). This results from the fact, that for uncoated and closed contact point, the end-side section 25 of the clamping side 20 is located within the contour of the material rail, in fact with a flat extension which is equal to or greater than the nominal cross-section of the conductor 23 which is to be clamped (refer Figure 3). The all-sided metal enclosed conductor trap 24 allows at first a force-free insertion of the forward end of the electrical conductor into the trap and prevents thereupon undesired deflecting movements of the front end of the conductor, when an axial force is applied manually for the insertion of the conductor in the contact point (so-called plug-in connection). Figures 4 and 5 demonstrate the functional sequence in the insertion of the electrical conductor in the contact point, whereby the formation of the collar inner wall surface 15 as smooth and flat-shaped inclined plane reduces the axial force, which is to be applied on the electrical conductor for the plug-in connection. The described embodiment of a spring-loaded clamped connection as per the invention considers also the requirement that it should be possible to use spring-loaded clamped connections of this type for non-pluggable electrical conductors (e.g. for fine-wire flexible conductors) also and/or to remove a clamped electrical conductor from the contact point. For this purpose, the clamping side 20 of the leaf spring has a protrusion 26 (refer Figure 5), which is provided outside the contour of the material rail in such a way that a spinning tool 27 placed on the protrusion and mainly perpendicular to the top side of the busbar piece pushes back the clamping side up to a position, in which the contact point is fully open (see Figure 6). We Claim : 1) Spring-loaded clamped connection with a busbar piece and a leaf spring for the connection of an electrical conductor, - said busbar piece being made of a flat material and has an opening for inserting the conductor, which is in the form of a rectangular material rail, having a collar extending in the direction of conductor insertion, - said leaf spring having a clamping side, the end of which dips into the rail in such a way that with a collar inner wall surface of the material rail, it forms a contact point for the electrical conductor, characterised in that - a cross-edge (22) projecting towards the electrical conductor (23) and extending in the direction of conductor insertion is provided at the collar inner wall surface (15), which with the clamping side end forms the contact point, the clamping side of the leaf spring is dimensioned and shaped in such a way that in the position of the clamping of the electrical conductor, the end-side clamping edge (21) of the clamping side end more or less faces the cross-edge present at the collar inner wall surface. 2) Spring-loaded clamped connection as claimed in claim 1, wherein : - the cross-edge present on the collar inner wall surface (15) is formed by the bottom edge (22) in direction of conductor insertion of the collar of the material rail, which for this purpose is advanced towards the electrical conductor which is to be clamped. 3) Spring-loaded clamped connection as claimed in claim 2, wherein : - the collar inner wall surface of the region of the collar, the edge (22) of which forms with the clamping side end of the leaf spring the contact point, is designed as an inclined plane (15) with smooth transitions formed without jerk or jolt. 4) Spring-loaded clamped connection as claimed in any one of the preceding claims, wherein : - the leaf spring is mainly bent U-shaped and has a locating side (19) at its end which is opposite to the clamping side, which along with the clamping side (20) of the leaf spring extends into the same material rail of the busbar piece and which rests against the collar inner wall surface (14), which faces the collar inner wall surface (15) which forms the contact point. 5) Spring-loaded clamped connection with a busbar piece and a leaf spring for the connection of an electrical conductor, - said busbar piece is made of a flat material and has an opening for inserting the conductor, which is in the form of a rectangular material rail, and having a collar extending in the direction of conductor insertion, - said leaf spring having a clamping side, the end of which dips into the rail in such a way that with a collar inner wall surface of the material rail, it forms a contact point for the electrical conductor, characterised in that - for uncoated and closed contact point, an end-side section (25) of the clamping side of the leaf spring is located within the contour of the material rail, in fact with a flat extension of the section, which is equal to or greater than the nominal cross- section of the conductor is to be clamped, in such a way that the ring-shaped, closed collar inner wall surfaces with the end-side section of the clamping side form a metal-enclosed conductor trap (24) for the forward end of the electrical conductor is to be inserted. 6) Spring-loaded clamped connection with a busbar piece and a leaf spring for the connection of an electrical conductor, - said busbar piece is made of a flat material and has an opening for inserting the conductor, which is in the form of a rectangular material rail, having a collar extending in the direction of conductor insertion, - said leaf spring having a clamping side, the end of which dips into the rail in such a way that with a collar inner wall surface of the material rail, it forms a contact point for the electrical conductor, characterised in that - a middle section of the clamping side of the leaf spring outside the contour of the material rail has a protrusion (26) in the direction of the spring clamping force of the clamping side of the leaf spring to such an extent that a spinning tool (27) placed on this protrusion and mainly perpendicular to the surface of the busbar piece pushes back the clamping side up to a position, in which the contact point is fully open. 7. A spring loaded clamped connection, substantially as herein described, particularly with reference to the accompanying drawings. The invention relates to a spring-loaded clamped connection for the connection of an electrical conductor, which in conformance to the class has a busbar piece with a rectangular material rail, into which the clamping side end of a leaf spring dips in such a way that the clamping side end with a collar inner wall surface of the material rail forms a contact point for the electrical conductor. It is suggested that for the collar inner wall surface of the material rail a new formation is used with a cross-edge/lateral edge and to provide the contact point for the electrical conductor in the depth of the material rail, through which simultaneously a metal-jacketed conductor trap is formed.

Documents:

445-KOL-2003-CORRESPONDENCE.pdf

445-KOL-2003-FORM 27.pdf

445-KOL-2003-FORM-27.pdf

445-kol-2003-granted-abstract.pdf

445-kol-2003-granted-claims.pdf

445-kol-2003-granted-correspondence.pdf

445-kol-2003-granted-description (complete).pdf

445-kol-2003-granted-examination report.pdf

445-kol-2003-granted-form 1.pdf

445-kol-2003-granted-form 18.pdf

445-kol-2003-granted-form 2.pdf

445-kol-2003-granted-form 3.pdf

445-kol-2003-granted-form 5.pdf

445-kol-2003-granted-gpa.pdf

445-kol-2003-granted-priority document.pdf

445-kol-2003-granted-reply to examination report.pdf

445-kol-2003-granted-specification.pdf