Patent Application
20130231012
The invention relates to a crimp barrel and to a connecting element having such a crimp barrel.
Joining methods with which two components are mechanically connected to each other by means of plastic deformation are used, among other places, in electrical engineering. Such mechanical joining methods are also referred to as crimping and constitute an alternative to conventional connections such as soldering or welding. Crimping is used especially to create a homogeneous connection between a conductor and a connecting element that is difficult to undo and that ensures high electrical and mechanical reliability. The connecting element is often a plug with an appropriate crimp barrel. Wherever it is not easily possible to lay a wire that already has plugs, the wire alone is laid all the way to its destination site and only there is an electric contact part installed at the end of the conductor (for example, by crimping a plug onto it).
Crimping pliers (or a crimping tool) are used to non-positively connect the crimp barrel of the plug to the wire. These tools are usually operated by a toggle mechanism since manual force is not sufficient to achieve a permanent deformation of the crimp barrel. This connection technique has found widespread use, particularly in the realm of high-frequency electronics and telecommunications, since it offers not only connection reliability but also a considerable simplification in terms of handling. This procedure is carried out with special crimping pliers. Here, the tool and the compressive force of the crimping pliers have to be precisely adapted to the crimp barrel. A gas-tight connection is created when crimping is carried out properly. The deformation of the crimp barrel and of the small-gauge conductor gives rise to a structure that is largely shielded from oxygen and whose interior is thus largely protected against corrosion.
However, if insufficient force is applied during the crimping procedure or if the crimping tool used is too big, then the small-gauge conductors are inadequately compressed. In this case, oxygen can reach the individual small-gauge conductors. This brings about an increase in the transfer resistance between the conductor and the crimp barrel due to corrosion of the individual small-gauge conductors. Moreover, the risk exists that an incompletely compressed conductor can be pulled out of the crimp barrel. Furthermore, the cross sections of bulky and small-gauge conductors can be impermissibly reduced if the compression is excessive or if the crimping tool is too small. This can cause the current carrying capacity of the connection to be impermissibly diminished as a result of the reduced cross section. Moreover, if the compressive force is exceeded to an extreme extent, there is a risk that, in the case of small-gauge conductors, individual conductors might be sheared off. Furthermore, the crimp barrel can become unusable if it cracks or ruptures.
Therefore, when it comes to making a reliable crimped connection, crimping profiles that are precisely adapted to the crimp barrel and to the conductor cross section are used to achieve a precisely prescribed deformation of the crimp barrel and of the conductor. Document DE 10 200 004680 A discloses a crimp barrel whose shaping makes it possible to crimp conductors in the small cross section range from 0.08 mm2 to 0.13 mm2 Since the conductor cross sections can also be significantly larger (for example, 0.35 mm2), different crimp barrels and crimping tools that are suitable for these cross sections have to be kept on hand. Therefore, it would be desirable to put forward crimp barrels that are equally suited for wires with different cross sections and that can thus be applied by the same crimping tool.
Consequently, it is the objective of the invention to put forward a crimp barrel that is equally suited for wires with different cross sections in order to make a reliable connection between the wire and the crimp barrel.
This objective is achieved by a crimp barrel comprising a base part and at least two deformable crimping wings in order to make a crimped connection with a wire, whereby the crimping wings each have a first zone connected to the base part, a second zone, and a middle zone situated between the first zone and the second zone, whereby the base part is thicker than the middle zone of the crimping wings, the first zone tapers from the base part towards the middle zone, at least on a first side, and the second zone tapers further starting from the middle zone, at least on a second side that is opposite from the first side.
The interaction of a relatively thick base part and crimping wings that are thinner according to the invention is decisive for the fact that this crimp barrel can yield a reliable crimped connection between the crimp barrel and the wire equally well for larger and for smaller wire cross sections. The base part has to have sufficient mass so that, after the crimped connection has been made, it can form a solid bottom for the connecting element with a strong connection between the crimp barrel and the wire. For this purpose, the base part can have a thickness of, for instance, 0.8 mm, which means, for example, that wires with cross sections between 0.35 mm2 and 0.75 mm2 can be reliably crimped with a crimp barrel according to the invention. The tapering in the thickness of the first zone of the crimping wings is necessary so that, on the one hand, there is still enough material in the side area of the crimped connection and so that, on the other hand, an optimal compacting of the conductor can be achieved by means of the ratio thus established between the height and width of the crimped connection. Here, the term “tapering” refers to the reduction in the thickness of the crimping wings, which can be uniform or non-uniform. The further tapering of the second zone allows the crimping wing to roll up in this zone when the crimped connection is made, resulting in a reliable crimped connection with a large material cross section that presses from above onto the wire and onto the bottom part situated underneath it (with the base part as a part of it). For example, the thickness of the middle zone can be between 0.4 mm and 0.5 mm In this context, the term “zone” refers to a section in the crimping wing having a certain length as seen perpendicular to the envisaged wire direction. As seen in a sectional side view, the tapering can have any suitable shape. It can be, for example, monotone or it can be provided with a contour (non-monotone). Examples of monotone tapering would be tapering along a circular arc or else linear tapering. Within the scope of the present invention, the person skilled in the art can also consider other tapering shapes.
Here, the term “crimped connection” refers to any form of connection that creates a mechanically strong connection through material deformation (crimping) of the barrel and of the object when a mechanical pressure is exerted onto an object surrounded by a barrel. When it comes to the crimping of wires, the surrounded object is the stripped wire, so that a good electrical contact with the crimp barrel can be established by means of the crimped connection. Here, the term “barrel” does not necessarily refer to a closed shape before the crimped connection is made. For example, before the crimped connection is made, the barrels can be open or closed barrels into which the stripped wire is laid or inserted. Open barrels are usually available with a pre-curved shape (crimp shape), so that the crimped connection can be easily made by means of an appropriately shaped tool. The crimp shape is preferably in the form of a “V”, with a rounded-off bottom, in which the base part and the first zones of the crimping wing form the base of the rounded-off V-shape. The completed crimped connection has a bottom and side area having an approximately rectangular cross section. The side on which, when the crimping tool is applied, the crimping wings touch each other, roll up and press on the wire situated underneath is referred to as the top of the crimped connection. Accordingly, the opposite side (bottom part) of the crimp barrel is referred to as the bottom. The parts between the bottom and the top are the above-mentioned side areas. The first side is defined as the side of the crimp barrel that completely faces the wire after the crimped connection has been made. Accordingly, the second side is the side of the crimp barrel that is opposite to the first side. The second side of the crimping wings refers to the side of the crimping wings that faces away from the wire, at least in the bottom area and in the side areas after the crimped connection has been made.
The crimp barrels according to the present invention, at least in the area of the base part and of the crimping wings, have to consist of readily deformable and electrically conductive material such as a copper alloy (for example, brass, bronze, copper, nickel silver), steel or aluminum alloys. The crimping wings can have, for example, a rectangular cross section as seen in the direction leading from the base part to the second zone. So that the electric current can be transmitted from the wire via the crimp barrel, for example, to an electric device, the crimp barrel is preferably part of a connecting element that is provided for purposes of connection to the electric device, and/or the crimp barrel is connected to the electric device via an electrically conductive path. Crimping tools are commercially available tools for making a crimped connection between a crimp barrel and an electric wire, for example, hand-held crimping tools.
The term “wire” here comprises all kinds of electric wires with suitable cross sections, for example, single-strand or multi-strand wires or else wires consisting of numerous fine flexible leads.
In one embodiment, the base part has a constant thickness in the uncurved state. This thickness can be, for instance, 0.8 mm Here, the base part has to have sufficient mass so that, after the crimped connection has been made, it can form a solid bottom for the connecting element, with a strong connection between the crimp barrel and the wire. A constant thickness of the base part is advantageous so that the base part, as the support area under the wire, has enough stability to withstand pressure while the crimped connection is being made. A constant thickness translates into a sturdy crimped bottom.
In one embodiment, the first zone tapers linearly in the uncurved state. In the present invention, the term “linear tapering” refers to a decrease in the thickness of the material as seen in a sectional side view along a straight line with a certain gradient. Non-linear tapering, on the other hand, would be tapering like a circular arc, e.g. This tapering provides sufficient material in the area of curvature adjoining the base part, so that the compressed volume of the wire in the crimp barrel has a height-to-width ratio that allows compacting of the conductor in the wire. The first zone is then on the crimped bottom in the crimped state, at least partially as a side area (where the crimping wings are at least not severely deformed). In this manner, a gas-tight crimped connection with good electrical contact and conductive properties can be made.
In an alternative embodiment, the first zone has at least a first sub-zone adjoining the base part and at least a second sub-zone adjoining the middle zone, whereby the tapering in the first and second sub-zones is of a different magnitude in the uncurved state. In this manner, in addition to the above-mentioned advantages (in the case of linear tapering), a curvature of the first side that is virtually like a circular arc is achieved in the crimp shape before the crimped connection is made. The wire can fit especially well into this virtually circular curved first side. For this purpose, the tapering is greater in the first sub-zone than in the second sub-zone, since the crimping wings are more markedly curved in the first sub-zone for making the crimp shape than in the second sub-zone. The term “more markedly” refers here to a linear tapering with a greater gradient. In this manner, a virtually circular curved first side can be easily made. For this purpose, in one embodiment, the first sub-zone adjoins the second sub-zone. For this purpose, in another embodiment, the tapering in the first and second sub-zones is configured linearly with a different gradient. Both of these embodiments can also be combined. If the tapering in the second sub-zone were to be more marked than in the first sub-zone, then it would hardly be possible to create a circular first side crimp shape in the form of a “V”, and the support for the wire that is to be crimped would not be as good, since there would be more room in which the wire could slip. The tapering between the base part and the middle zone should be as steep as possible so that the crimping wings are as long as possible in the crimped state. Consequently, this promotes an ideal crimping behavior.
In another embodiment, the lateral extension of the base part and of the crimping wings is adapted in such a way that, in the crimped state, a bottom part is made up of the base part and of the first sub-zones. Thus, with normal material thicknesses in the base part and with the tapering in the first sub-zone, even wires with very small cross sections can be reliably crimped. The term “lateral extension” refers to the extension in the direction that is perpendicular to the envisaged direction of the wire in the crimp barrel. This achieves a good stability of the crimp shape.
The tapering of the second zone can be, for example, monotone or it can be provided with a contour (non-monotone). An example of monotone tapering would be tapering along a circular arc. Within the scope of the present invention, the person skilled in the art can also consider other shapes for the tapering. In one embodiment, the second zones of the crimping wings taper linearly in the uncurved state. For example, the second zone tapers at a gradient of approximately 20° relative to the second side in the middle zone. When the crimping wings are in the uncurved state, the faces of the second zone are perpendicular to the second side of the first and second zones as well as of the base part. During the crimping (making the crimped connection), this linear tapering of the second zone on the second side causes the crimping wings to roll up in the shape of a spiral that, as a shared large surface, presses on the wire. This prevents the second zones of the crimping wings from being left behind as sharp front edges during the crimping that could then push through the wire and possibly shear off one or more wire strands. Since the second zones roll up to form a spiral, a reliable and strong crimped connection with the wire is made.
In another embodiment, the magnitude of the linear tapering of the second zones is adapted in such a way that the second sides of the second zone are essentially parallel to each other in the case of a crimp barrel with an open crimp shape in the form of a “V”. This facilitates the insertion into the crimping trough of the crimping tool, which leads to a good crimping process. The expression “essentially” includes all crimp shapes that differ by a few degrees from an exact parallelism of the crimping wings in the second zones.
In one embodiment, in the uncurved state, the middle zone tapers along the first side toward the second zone. Here, the crimping wing thickness is defined in such a way that the ratio of the material thickness to the cross sectional shape is similar to a standard crimp barrel. The part of the middle zone facing the first zone can have a thickness, for instance, of 0.5 mm, which tapers toward the second zone, for example, to 0.4 mm This tapering is preferably linear. In a preferred embodiment, the tapering of the middle zone of the first side extends likewise over the second zone as well. This further promotes the rolling up of the second zones during the crimping procedure.
In another embodiment, the second side of the crimping wings outside of the second zone and the bottom of the base part in the uncurved state form a flat surface. This is advantageous from a manufacturing standpoint (e.g. in a stamping process) during the production of the crimping wings. Since the deformations are easier to produce from above, it is advantageous if the bottom remains flat (planar).
The invention also relates to a connecting element with a crimp barrel according to the present invention. Preferably, such a connecting element also comprises at least one insulation crimp for securing a wire (with or without insulation) and a functional part that is in electrical contact with the crimp barrel. The insulation crimp protects the crimped connection between the wire and the crimp barrel against mechanical effects such as bending load, buckling load and tensile load as well as against vibrations, all of which only act on the insulation crimp in case of a good crimped connection. The insulation crimp can be made of any desired material that can be sufficiently deformed mechanically in order to create a proper crimped connection. Preferably, the insulation crimp is made of the same material as the crimp barrel. Especially preferably, the entire connecting element is made of the same electrically conductive material, for example, brass, bronze, copper, nickel silver or steel. Preferably, the functional part is a plug. This makes a good connection to the functional part possible.
These aspects as well as other aspects of the invention are shown in detail in the figures below.
BM (see broken lines). The second zone B2 has a first side S1 that, corresponding to the surface of the middle zone MB, likewise extends, i.e. with the same tapering angle, along the second zone B2 as well. The other opposite side S2 of the second zone B2 tapers V2 markedly toward the tip of the crimping wings 12. At the boundary to the middle zone MB, the second zone B2 has a thickness d2 (e.g. 0.4 mm) that is considerably larger than the thickness d3 (e.g. 0.15 mm) of the second zone B2 at its tip. In this example, the tapering V2 is configured in such a way that the second side S2 in the area of the second zone B2 encloses an angle of approximately 70° to the face of the second zone B2. This corresponds to an angle of approximately 20° between the two sides S2 in the middle zone MB and in the second zone B2. Furthermore,
In contrast,
The embodiments shown here are merely examples of the present invention and should not be construed in any limiting manner. Alternative embodiments considered by a person skilled in the art are likewise encompassed by the protective scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102010031505.2 | Jul 2010 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP11/62033 | 7/14/2011 | WO | 00 | 5/1/2013 |
