Crimp element for crimp connection

[0001] The invention relates to a collet and a connecting element with such a collet.

Background of the invention [0002] A joining technique in which two elements are mechanically joined together by plastic deformation is used, among others, in electrical engineering. Such mechanical joining techniques are also called crimping and are an alternative to conventional joints such as soldering or welding / welding. Crimping is used in particular to make a homogeneous, hardly detachable connection between the conductor and the connecting element, which ensures high electrical and mechanical reliability. The connecting element is often a plug with a suitable collet. Wherever it is not possible to lay the finished cable with plugs, the cable itself is laid to its destination and only there the electrical contact part is fixed at the end of the cable (e.g. by tightening the plug).

[0003] Crimping pliers with a cable are connected by force connection using pliers (or a crimping tool). They usually operate through the knee lever, because the hand force is too weak to permanently deform the collet. Especially in the field of high-frequency electronics and telecommunications, this type of connector has adopted, because in addition to the reliability of the connection, it also brings a significant simplification of operation. This operation is carried out using special clamping pliers. The tool and the pressure force of the crimping pliers must be adjusted exactly to the collet. When crimped, the gas-tight connection is formed when properly made. Due to the deformation of the collet and the thin-stranded conductor, a structure is created that is largely insulated from oxygen, and therefore, in the interior is largely protected against corrosion.

[0004] However, if sufficient force is not applied to the crimping or if a too large clamping tool is used, then the thin-stranded wires are insufficiently compressed. In this case, oxygen may reach the individual thin-wire conductors. As a result, the transition resistance between the conductor and the collet increases as a result of corrosion on individual thin-wire conductors. In addition, there is a risk that the incompletely compressed hose can be pulled out of the collet. Also, if the compression tool is too tight or the tool is too small, solid and thin-stranded wires may cause an unacceptable reduction in cross-sections. This may cause an unacceptable reduction in the current carrying capacity of the connection due to the reduced cross-section. In addition, if the pressure force is exceeded excessively, there is a risk of individual wires being cut off with thin-wire conductors. In addition, the collet may become unusable due to cracks or breaks.

[0005] For reliable clamping, clamping profiles precisely adapted to the collet and cross-section of the conductor are used in order to achieve the precisely defined deformation of the collet and the conduit. Document DE 102008004680 A discloses a collet whose shape allows crimping of wires in the range of small cross sections from 0.08 mm2 to 0.13 mm2. Because the cross-sections of the conductors may also be significantly larger (e.g. 0.35 mm2), various collets and crimping tools suitable for these cross-sections must be available on site. Therefore, it would be desirable to provide crimp sleeves that are equally suitable for cables with different cross-sections and can therefore be fastened with the same crimp tool.

[0006] JP ​​2004 303 526 A shows a collet according to the preamble of claim 1.

Summary of the Invention [0007] It is therefore the object of the invention to provide a collet that is equally suitable for cables with different cross-sections for producing a reliable connection between the cable and the collet.

[0008] This task is solved by a collet according to claim 1.

[0009] The interaction of the relatively thick base part and according to the invention the shadow of the shorter clamping wings determines that with this collet, for both larger and equally smaller cable cross-sections, a reliable crimp connection between the collet and the collet can be made cable. The basic part must have sufficient weight to form a solid foundation for the connecting element with the permanent connection of the collet and cable after the compression connection has been made. For this purpose, the base part can have a thickness of, for example, 0.8 mm, whereby cables with cross-sections from 0.35 mm2 to 0.75 mm2 can be reliably crimped using the collet according to the invention. The narrowing of the thickness of the first clamping flap area is necessary so that, on the one hand, there is still enough material in the lateral clamping connection area, and on the other hand that optimum condensation can be achieved by using the ratio between the height and width of the clamping connection. The narrowing is called reducing the thickness of the clamping wings, which can be even or uneven. Further narrowing of the second area allows the clamping flap to be folded in this area when making the clamp connection, so that there is a reliable crimp connection with a large cross-section of material that presses from above on the cable and the underlying bottom part (with the basic part as its part). The thickness of the central area can be, for example, from 0.4 mm to 0.5 mm. The term area means a segment in the clamping flap with a length seen perpendicular to the intended direction of the cable. The shape of the narrowing can have any suitable form when viewed from the side. It can, for example, be uniform or have a contour (non-uniform). An example of uniform narrowing would be a narrowing along a circular arc or a linear narrowing. One of ordinary skill in the art may also consider other shapes of narrowing in the context of the present invention.

[0010] In this connection, a crimped connection is any form of connection which, by exerting mechanical pressure on an object surrounded by a sleeve, creates a mechanically permanent connection by deforming the material of the sleeve and the object (crimping). The surrounded object when crimping cables is an insulated cable so that a crimp connection can make good electrical contact with the crimp sleeve. The term "sleeve" does not necessarily mean a closed form before making a crimp connection, also referred to herein as a crimp connection. The sleeves before the compression connection can be, for example, open or closed sleeves into which an insulated cable is inserted or plugged in. Open sleeves are usually supplied in a pre-bent form (clamping form) to be able to easily make a crimp connection with a suitably shaped tool. The clamping form preferably has a V-shaped rounded bottom, in which the base part and the first clamping flap areas form the base of the rounded V-shaped shape. The completed clamping connection has a lower and lateral area which has an approximately rectangular cross-section. The side on which the clamping wings are in contact with the clamping tool, curling and pressing on the cable underneath is called the top side of the clamping connection. The opposite part (bottom area) of the collet will be called the underside accordingly. The parts between the underside and the top are the above-mentioned side areas. The first side is called the side of the collet, which after the compression connection is completely facing the cable. The other side is respectively the opposite side to the first side of the collet. The other side of the clamping flaps means the side of the clamping flaps, which at least in the bottom and side areas after the clamping connection has been turned away from the cable.

[0011] The collets according to the present invention must be made of easily deformable and electrically conductive material such as copper alloy (for example brass, bronze, copper, new silver), steel or aluminum alloys at least in the area of ​​the base part and the clamping wings. The clamping wings may have, for example, a rectangular cross-section in the view direction from the base part towards the second area. In order for the electric current to be transmitted from the cable through the collet, for example to an electrical device, the collet is preferably a part of a connecting element that is intended to be connected to an electrical device and / or is connected to it by an electrically conductive path. Crimping tools are commercially available tools for making a crimp connection between a collet and an electric cable, for example hand crimping tools.

[0012] The term "cable" here includes all types of electric cables with suitable cross sections, for example single or multi-strand cables or cables with many thin facing wires.

[0013] In an embodiment of the invention, the base part in a non-curved state has a constant thickness. This thickness can be, for example, 0.8 mm. The base part must have sufficient mass to form a solid foundation for the connecting element with the permanent connection of the collet and cable after the clamp connection has been made. The constant thickness of the base part is preferred so that the base part as a contact area under the cable has sufficient stability to exert pressure when making the clamp connection. The constant thickness ensures a stable clamping ground.

[0014] In an embodiment of the invention, the first area has at least a first sub-area connecting to the base part and at least a second sub-area connecting to the central area, wherein the tapering in the first and second sub-areas in a non-curved state has a varying degree. In this way, in addition to the above advantages (with linear narrowing), an almost circular curvature of the first side in the clamp form is obtained before the clamp joint is made. The cable can fit particularly well into this almost circularly curved first page. For this purpose, the narrowing is greater in the first sub-area than in the second sub-area, because the clamping wings in the first sub-area to produce the clamp form are more curved than in the second sub-area. The term "stronger" here means a linear narrowing with a greater slope. In this way, an approximately circularly curved first page can easily be produced. In one embodiment, the first sub-area borders for this purpose with the second sub-area. In another embodiment, the constriction in the first and second sub-areas is made linearly for this purpose with a different slope. Both embodiments can also be combined with each other. If the narrowing in the second sub-area was greater than in the first sub-area, then it would be difficult to create a circular first side in the V-shaped clamp form and support for the crimped cable would be less advantageous because there would be more slack for the cable sliding. The narrowing between the base part and the central area should be as steep as possible so that the clamping wings in the clamped state are as long as possible. This supports ideal crimping characteristics.

[0015] In a further embodiment, the lateral dimension of the base part and the clamping wings is adjusted such that the bottom part in the clamped state consists of the base part and the first sub-areas. In this way, using normal material thicknesses in the base part and narrowing in the first sub-area, cables with very small cross-sections can also be reliably clamped. The term "lateral dimension" means a dimension in a direction that is perpendicular to the intended direction of the cable in the collet. As a result, good clamping stability is achieved.

[0016] The narrowing of the second areas may for example be uniform or may have a (non-uniform) contour. An example of uniform narrowing would be a narrowing along the arc of a circle. One of ordinary skill in the art may also consider other shapes of narrowing in the context of the present invention. In one embodiment, the second areas of the clamping tabs narrow in a linear manner in a non-curved state. The second area tapers, for example, with a slope of about 20 ° relative to the other side in the middle area. The front sides of the second region in the non-curved condition of the clamping wings are perpendicular to the second side of the first and second regions and the base part. This linear narrowing of the second area on the other side leads during crimping (crimping) to wind the clamping wings into a worm shape, which as a common large surface presses on the cable. This prevents the other areas of the clamping flaps from remaining during crimping, forming sharp front sides, and thus squeezing through the cable and eventually cutting off one or more wires of the cable. The winding of the second areas in the shape of a worm makes it possible to obtain a reliable durable clamp connection with the cable.

[0017] In a further embodiment, the degree of linear narrowing of the second areas is adapted such that the second sides of the second areas in the collet with an open V-shaped clamp are substantially mutually parallel. This makes it easier to insert the clamping tool into the crimping mold, which leads to a good crimping process. The expression "essentially" includes all clamping forms which differ by several degrees from the exact parallelism of the clamping wings in the second areas.

[0018] In one embodiment, the middle region in a non-curved state narrows along the first side to the second region. Here, the thickness of the clamping wings is defined so that the ratio of material thickness to cross-sectional shape approaches the standard collet. The part of the central area facing the first area may have a thickness of, for example, 0.5 mm, which decreases towards the second area, for example, to 0.4 mm. This narrowing is preferably linear. In a preferred embodiment, the narrowing of the central area of ​​the first page extends equally to the second area. This aids even more the folding of the second areas when crimping.

[0019] In another embodiment, the other side of the clamping wings outside the second area and the underside of the base portion in a non-curved condition form a flat surface. It is technologically advantageous (e.g. in the punching process) in the manufacture of clamping wings. Since the deformations can be made more easily from above, it is advantageous if the underside remains flat (planar).

[0020] The invention further relates to a coupling element with a collet according to the present invention. Such a connecting element preferably further comprises at least one insulation clamp for fixing the cable (with or without insulation) and a functional part in electrical contact with the collet. The insulating clamp protects the clamping connection between the cable and the collet against mechanical influences such as bending, buckling and tensile loads as well as vibrations, all of which only act on the insulating clamp if the connection is good. The insulation clamp can be made of any material that is sufficiently mechanically deformable for a sufficiently good clamping connection. The insulating clamp is preferably made of the same material as the collet. Particularly preferably, the entire connecting element is made of the same electrically conductive material, for example brass, bronze, copper, new silver or steel. The functional part is preferably a plug. This enables a good connection with the functional part.

Brief Description of the Drawings [0021] These and other aspects of the invention are shown in detail in the following drawings.

Fig. 1: Collet according to the state of the art in a pre-bent form (clamping form).

Fig. 2: collet according to the present invention in a pre-bent form (clamp form).

Fig. 3: collet according to the present invention in a non-curved form.

Fig. 4: clamp connection between the collet and cable (a) according to the state of the art and (b) according to the present invention.

Fig. 5: an embodiment of a connecting element according to the present invention.

Detailed Description of Embodiments [0022] Figure 1 shows the collet (CF-SdT) in a pre-bent form (cross section perpendicular to the later cable direction in the clamp connection) according to the prior art. The pre-bent form (clamping form) has the shape of the letter "V" with a curved base and upwardly pointing clamping wings, the maximum mutual distance of which is BR1 and is the width of the clamping form CF. The radius R1 of the curvature of the curved base is selected so that a cable 4 with a specific cross section can be inserted into the curved base. To be able to obtain a radius R1 of curvature suitable for cable 4, the base must have a thickness of a1. The collet has a first side S1, which in the crimped connection faces the cable, and a second side S2, which is the side of the collet opposite the S1 side. The tops of the clamping wings P have a thickness of a2, smaller than the thickness a1, so that the clamping wings can curl during crimping.

[0023] Figure 2 shows the collet 1 in a pre-bent form (CF form) as a cross-section along the AA direction, see also figure 5. The pre-bent CF form also has a "V" shape with the curved base part 11 and facing upwards clamping wings 12 whose maximum mutual distance is BR2 and is the width of the clamp form CF. The radius R2 of the curvature of the curved base is selected so that a cable (not shown here for clarity) with a specific cross section can be inserted into the curved base. To be able to obtain a radius of curvature R2 suitable for cable 4, the base must have a thickness d1. The first part of the clamping wings 12 is connected to the basic part 1, which, as shown here, is divided into two sub-areas L1 and L2 (hatched in the left clamping wing). In alternative embodiments, instead of L1 and L2, the first area could also be made without dividing into sub-areas. The clamping wings 12 narrow V1 clearly in sub-areas L1 and L2, which allows to create the appropriate radius of curvature for individual cables with different cross-sections. The collet 1 has a first side S1, which in the crimp connection faces the cable, and a second side S2, which is the side of the collet opposite the S1 side. The middle area of ​​the clamping wings 12 has a thickness d2, smaller than the thickness d1, which narrows V2 further in the second area of ​​the clamping wings, so that the clamping wings 12 can also be folded when crimping in the case of cables with small cross-sections.

[0024] Figure 3 shows the collet in a non-curved UK form as a cross-section along the AA direction, see also figure 5. Base part 11 with a thickness d1 (e.g. 0.8 mm) and lateral dimension D (perpendicular to the later cable direction in the clamp connection ) forms the central area of ​​the collet 1. In this embodiment, clamping clamps 12 connect to the base part in this embodiment, each of them consisting of a first area B1, a central area MB and a second area B2. The clamping wings 12 are connected by a first area B1 to the base part 11 along the entire length of the clamping wings 12 (see Figure 5). In order to be able to make a crimp connection with the cable in a suitable form in the subsequent clamping connection, which ensures a secure fit of the cable and eliminates the risk of cutting it, the thickness of the clamping wings 12 clearly narrows in the first area B1, which contains two sub-areas L1, L2 (hatched). Here, the narrowing of V11 in the first L1 sub-area is greater (greater decreases 13) than the reduction of V12 in the second L2 sub-area. The first area B1 is then connected to the central area MB of the clamping wings 12 with a thickness of, for example, 0.5 mm at the border with the first area B2. In this central area MB, the clamping wings 12 narrow further, but not as much as in the first area B1. If the first side S1 is extended thoughtfully along the surface of the central area MB, then the narrowing angle β is obtained with the thought extended side S2, which is flat in the base part 11, the first area and the middle area BM (see dashed lines). The second area B2 has the first side S1, which, according to the surface of the central area MB, extends evenly, i.e. with the same narrowing angle, also along the second area B2. The other opposite side S2 of the second area B2 tapers V2 clearly towards the top of the clamping flaps 12. The second area B2 has a thickness d2 (e.g. 0.4 mm) on the border with the central area MB, which is clearly greater than the thickness d3 (e.g. 0.15 mm) of the second area B2 at its apex. The constriction V2 in this example is shaped so that the other side S2 in the area of ​​the second area B2 forms an angle of about 70 ° with the face of the second area B2. This corresponds to an angle of about 20 ° between the other sides of S2 in the middle area MB and in the second area B2. Figure 3 also shows the cross-section of the central area MB parallel to the basic part 11. The central area MB has along this section a rectangular shape with a thickness dm, which, however, depends on the location of the cross-section. The closer the cross-section lies to B2, the smaller dm. Directly at the border with the second area B2, dm is equal to d2 For example d2 = 0.4 mm [0025] Figure 4 shows crimping sleeves with cables after crimping using a suitable crimping tool for crimping sleeves (a) according to the state of the art and (b ) according to the present invention. Figures 4 (a) and 4 (b) are not shown here faithfully in scale relative to each other, so that the proportion of size cannot be transferred directly from one drawing to another. In figure 4a it can be seen that the prior art ferrules in the case of cables with a small cross-section 4 curl in such a way that the tops P of the ferrules clearly dig into the cable 4 and in this way can possibly also cut the cable. On the one hand, this leads to an insecure mounting of the clamping sleeve on the cable, on the other hand, it negatively affects the conductivity of the cable. Too small cross-sections of the conductor in the clamped state eventually lead to reduced conductivity in this area. In addition, the air connection could not be cut off in such a connection, which could result in corrosion damage to the clamp connection over time.

[0026] In contrast, Figure 4b shows the ideal form of a crimp connection with a crimp sleeve according to the present invention, wherein the crimped cable has a smaller cross-section than the ideal cross-section. The lower part 2 comprises a basic part 11 (0.8 mm thick) and the first sub-areas L1 of both clamping flaps 12. The lateral parts of the clamping connection are located on the outer areas of the lower part 2. On the upper side of the clamping connection, the clamping wings 12, due to their constructions shaped in accordance with the invention, easily curl in their second areas B2, without, however, cutting into the cable 4 with sharp edges (in contrast to the state of the art shown in Figure 4a). A crimped cable 4 with a primary cross-section of 0.5 mm2 has a rectangular cross-section here with good fastening and conduction properties. This S1 side or cable shape after the clamp connection is made possible for a wide range of cable cross sections only by using the collet according to the present invention.

[0027] Drawing 5 shows the connecting element 3 with the collet 1 in a top view (drawing 2 in a top view). The AA plane, in which Figures 2 and 3 are shown, is shown here with the line marked "A". The collet has a base part 11 between the clamping flaps 12. The collet in this embodiment is part of a connecting element 3, which further comprises two insulation clamps 31 for fixing the cable in the area with intact cable insulation. The insulating terminals 31 are intended to keep the mechanical loads on the cable 4 away from the clamp connection with the insulated cable 41. The connecting element 3 further comprises a functional part 32 which is in electrical contact with the collet. This functional part 32 can be, for example, a plug for connecting to an electrical device. The clamping wings 12 have tapered thicknesses relative to the base part 11, which is shown in Figure 5 as a hatched area. This narrowing for better clamping may extend even towards the insulation terminals 31 and functional part 32 (see area 34) in order not to subject these parts to excessive stress after the clamping. The collet or the entire connecting element can be made of the same electrically conductive material, for example copper alloys (brass, bronze, copper, new silver, etc.), steel or aluminum alloys.

[0028] The embodiments shown here are examples of the present invention only and should therefore not be construed as limiting. Alternative embodiments contemplated by one of ordinary skill in the art are equally within the scope of protection of the present invention.

List of references [0029] Clamping sleeve, basic part, clamping wings, lower part (= basic part + first subareas), connecting element, insulation clamp, functional part, cable, isolated part of the cable

B1 first area of ​​the clamping flap

L1 first sub-area of ​​the first area

L2 second sub-area of ​​the first area

B2 second clamping flap area

MB middle area of ​​clamping flap

S1 first side of the collet

S2 the other side of the collet

V1 narrowing in the first area

V11 narrowing in the first sub-area of ​​the first area

V12 narrowing in the second subarea of ​​the first area

V2 narrowing in the second area

UK collet in non-curved condition

CF collet (collet in pre-bent form)

CF-SdT collet (collet in pre-bent form) according to the state of the art

BR1 clamping width according to the state of the art

BR2

H1

H2

R1

R2

P

D d1 d2 d3 dm a1 a2 α

^β clamp width according to the present invention clamp height according to the prior art clamp height according to the present invention curved radius of the curved clamp according to prior art curvature radius of the curved clamp according to the present invention (it could be a line) tip of the clamp flaps according to prior art side dimension of the basic part thickness of the base part thickness of the second area thickness top of the second area thickness of the central area in cross-section view thickness of the basic part according to the prior art thickness of the top of the collet according to the prior art narrowing angle V2 in the second area narrowing angle in the central area

STOCKO Contact GmbH & Co. KG

Proxy:

84P37913PL00

EP 2 596 552 B1