Wire twisting pliers with clamping function

Abstract

Wire clamp (5) for fixing loose ends of wires for a pair of pliers (10) for twisting the wires, wherein the pliers have two pliers legs (1, 2) which are connected to one another in an articulated manner via a pliers rivet (3), characterized in that the wire clamp (5) is provided fastened to the pliers rivet (3).

Description

Technical FieldThe invention relates to a wire clamp for fixing loose ends of wires for a clamp for twisting the wires, wherein the clamp has two clamp legs which are connected to one another in an articulated manner by a clamp rivet. The invention also relates to pliers for twisting the wires, the pliers having two pliers legs which are connected to one another in an articulated manner by means of a pliers rivet.DESCRIPTION OF THE INVENTIONIn the field of the maintenance and maintenance of motors and transmissions, in particular in safety-critical applications such as aerospace technology, the use of wire fuses to secure screw connections against unintentional loosening is known. These are mechanical securing systems in which a so-called lead wire (also called securing wire) is guided through suitable bores in the screw head and / or nut. The free wire ends are then twisted together in order to create a form-fit and force-fit connection which effectively prevents the screw connection from being automatically loosened under operating conditions.In order to carry out this securing process, so-called drilling tongs are used in practice. These are hand-held tools which are specially designed for the uniform twisting of wire ends. In its typical embodiment, the twisting tongs have two tong-like gripping jaws, between which the wire ends to be twisted are clamped. By means of a rotatable pulling mechanism-regularly in the form of an axially movable handle with a return spring-the clamping mechanism is set in rotation, whereby the wire ends are twisted together. This process ensures uniform and reproducible twisting over the desired length of the wire. In many cases, the twisting tongs are additionally equipped with a cutting device in order to cut off the protruding wire ends to a defined length after twisting.Drilling tongs are used in particular in sensitive industrial applications in which there are the highest demands on process safety, functional reliability and avoidance of foreign bodies. In particular in the aerospace industry, it is absolutely necessary that no loose parts, chips or tool components can unintentionally get into safety-relevant assemblies when wire securing is used. Therefore, both the construction of the tool and the securing process itself are subject to stringent normative and safety requirements.The use of wire fuses in combination with drilling tongs represents a proven prior art for securing mechanical connections against oscillation loosening, thermally induced expansion effects and manipulation. The basic features of the twisting tong consist of a robust gripping mechanism, a torque-transmitting drawing mechanism for twisting and, if present, an integrated cutting device for post-processing the wire ends. The construction is usually made of high-strength tool steel, optionally with surface finishes to increase corrosion resistance in aggressive environments.Prior ArtElectronic side cutters of the nominal size of 125 mm are known, which are equipped with a wire holding function. This wire terminal serves to retain multi-core copper strands during the shortening of stripped ends in electronic wires. Copper wires generally exhibit an adhering behavior on the cutting edge during the cutting process and do not tend to spring away. However, it is known that, for wires of the same size and quality according to DIN ISO 5744:2006-09, Tables 1 and 2, the spring-off increases with increasing tensile strength of the wire material.The wire clamps used in the prior art are either plugged onto a tong leg or fastened in the joint region of both tong halves by means of an adapted screw connection. Both variants are only connected in a force-fitting manner and are thus not sufficiently secured against undesired detachment under mechanical stress. Constructions in which the wire clamp is an integral part of a special screw which at the same time serves as a joint connection of the tong legs are also known. These solutions require additional measures to secure the screw connection in order to prevent the pliers from coming apart.Furthermore, a variant is known in which the cutters are provided on one side with plastic parts which are intended to support a retaining function when separating wires. With regard to this embodiment with plastic inserts, additional disadvantages are evident: the connection between the inserted plastic and the tempered tool steel of the clamp must generally take place via an adapted adhesive connection. Such adhesive connections are subject to temperature-dependent influences as well as to the basic problem of the purely force-locking connection, which also remains non-destructively releasable. Added to this is the material-induced aging of the plastics used, in particular as a result of the loss of plasticizers, which leads to friability. This aging behavior is often underestimated in hand tools which are partially subject to changing climatic conditions.Various property rights publications are known in the art which deal with tong constructions and wire holding functions. DE 36 15 280 A1 describes a wire-tensioning clamp which is designed specifically for tensioning wires. Their construction takes into account ergonomic requirements for handling and angle of use and shows an embodiment in which the wire can be held securely during machining.DE 26 41 461 B2 discloses a wire clamp which is designed for a secure and stable fastening of wires. The solution described therein permits simple handling with simultaneously high connection reliability, which is relevant in particular for applications in which wire sections have to be fixed or secured against springing away.Known from DE 14 78 967 A1 is a forceps in which one of the two forceps jaws is rigidly connected to the forceps limb, while the second jaw can be moved via an adjustable mechanism. This embodiment enables a fine adjustment of the cutting or clamping action of the clamp in an application-oriented manner.EP 0 624 433 A1 describes pliers, in particular for securing rings, the halves of which are pivotably connected to one another via a threaded connection. This connection produces a particularly stable articulated construction which can also be transferred to other types of pliers in which an exact movement of the pliers jaws is necessary.By way of example, reference is made to the commercially available embodiment "Knipex Electronic Super Knips ®78 13 125 ESD", in which a wire clamp is integrated, which prevents the spring-away of wire sections during the separation.Disclosure of the InventionThe object of the invention is therefore to avoid disadvantages of the prior art and to provide a wire clamp for fixing loose ends of wires-especially on twist tongs-which makes it possible to hold wires securely on nut-screw combinations during the securing and shortening of seal joints and to prevent the loose wires from springing away. It is likewise necessary to ensure that the retaining function itself is secured against loosening.According to the invention, the object is achieved in that in the case of a wire clamp for fixing loose ends of wires for a clamp for twisting the wires of the type mentioned at the beginning, the wire clamp is provided fastened to the clamp rivet. Furthermore, the object is achieved in that, in the case of pliers for twisting the wires of the type at the outset, a wire clamp for fixing loose ends of wires is fastened to the pliers rivet.The invention is based on the principle that the tong rivet-which forms the articulated connecting element of the two tong legs-is additionally used as a fastening point for the wire clamp. As a result, the wire clamp can be integrated without changing the enveloping contour or impairing the pliers function. The effect is that loose wire ends are reliably and automatically fixed during the twisting or cutting process, whereby unintentional jumping away is avoided. At the same time, the plastic deformation of a tong rivet provided with a holding structure produces a positive-locking and self-locking connection between the wire clamp and the tong, which is permanently durable both in the radial and axial direction.This construction permits a reliable, durable and at the same time retrofittable integration of the wire holding function into existing tong designs-in particular also in combination tongs with an additional gripping function-without having to change the basic tong mechanism or have to access external additional parts.Compared to the known prior art, the proposed solution has several advantages. By fastening the wire clamp directly to the tong rivet of the tong, a particularly compact and installation space-neutral construction is produced, in which no additional fastening elements are required on the outside of the tong. The integration of the wire clamp into the existing functional element of the clamp enables a simple and cost-effective implementation as well as a stable, mechanically loadable connection.In contrast to plugged-on or screwed-on holding elements, which can become detached under load or during continuous use, the solution according to the invention provides a permanently secure fixing of the wire clamp. The plastically deformed and positively locking connection between the tong rivet of the wire clamp and the bore in the tong rivet reliably prevents the clamp from being rotated or pulled out.Another advantage is that the wire clamp is in close proximity to the cutting area, thereby allowing automatic retention of the cut ends when cutting wire ends. The unintentional jumping away of the wire pieces is thereby avoided, which is of importance in particular in safety-critical applications-for example in aviation and space technology.In addition, the holding function can be easily retrofitted in existing tong models without requiring a structural change of the tong body. The existing mechanics of the pliers are completely maintained, as are their gripping or cutting functions. The invention is thus suitable both for new constructions and for subsequent installation in existing tools.In an advantageous embodiment of the inventive wire clamp for pliers for twisting wires, the pliers rivet has a holding structure on its outer jacket, which is in particular corrugated, notched, grooved, napped, knurled and / or gridded. This structured surface achieves a particularly secure positive fit when the tong rivet is pressed plastically into a corresponding bore, which reliably prevents twisting or pulling out both in the radial and axial direction. This increases the mechanical stability and operational reliability of the connection even under repeated loading or vibration.In a further preferred embodiment of the wire clamp according to the invention, the tong rivet is introduced into a blind bore in a positively locking and plastically deformed manner, so that a plastic positively locking connection is produced between the bore jacket surface and the tong rivet jacket, which plastic positively locking connection prevents a relative movement in the radial and axial directions. This embodiment ensures a permanently fixed and self-locking connection which reliably prevents the tong rivet from being rotated or released both in the radial and in the axial direction. This results in a particularly robust and vibration-proof attachment of the wire clamp-ideally for applications under permanent mechanical stress.A further advantageous embodiment of the inventive wire clamp for pliers for twisting wires results from the wire clamp being made of spring steel wire. By using this material, the clamp has a high elastic restoring force and at the same time an excellent dimensional stability, whereby the wire ends are held reliably without the clamp deforming permanently during frequent use. In addition, spring steel wire is particularly resistant to fatigue and wear, which significantly increases the service life of the holding function.An advantageous further development of the wire clamp according to the invention provides that the wire clamp extends parallel to the cutting edges of the tongs, between the two tongs legs. This results in a particularly space-saving and contour-true arrangement in which the enveloping contour of the clamp is not changed. At the same time, this position enables a direct and reliable detection of the loose wire ends directly in the cutting region, so that these are automatically fixed when the cutters are closed-without additional alignment or manual intervention.A functionally particularly advantageous embodiment of the pliers according to the invention results from the fact that the pliers rivet has a holding structure on its outer side. This structure-for example in the form of a corrugation or knurl-permits an improved form-fit between the tong rivet and the bore, whereby the wire clamp fastened thereto is permanently secured against twisting and pulling out. This increases the mechanical reliability of the connection and ensures a stable holding function even when stress or vibration is repeated in use.A further technical advantage of a clamp according to the invention for twisting wires results if the clamp rivet is inserted into a blind hole bore in a positively locking and plastically deformed manner, so that a plastic positively locking connection is produced between the bore jacket surface and the clamp rivet jacket, which plastic positively locking connection prevents a relative movement in the radial and axial directions. This connection ensures a particularly secure and permanent fixing of the wire clamp, since it reliably prevents a relative movement both in the radial and axial direction. As a result, the holding function is ensured in a long-term stable manner even under permanent mechanical loading, vibration or temperature fluctuations, without the connection being able to be loosened or loosened.An advantageous further development of the pliers according to the invention provides that the pliers rivet forms a fixed bearing with the first pliers leg and a movable bearing with the second pliers leg in order to ensure that the legs slide without play. This bearing arrangement enables play-free and precise sliding of the two tong legs with respect to one another, which leads to uniform force transmission and high cutting accuracy. At the same time, wear is minimized, whereby the service life and functional reliability of the pliers are increased even in the case of frequent or intensive use.In a further preferred embodiment of the clamp according to the invention for twisting wires, the clamp is provided as a combined clamp with a gripping and cutting function. This enables multifunctional use of the tool, in which both the precise cutting and the selective gripping and positioning of workpieces can be carried out with only one tool. As a result, not only is the tool change reduced and the work sequence accelerated, but also the space requirement in the tool inventory is reduced, which is advantageous in particular in mobile or restricted use.Further embodiments and advantages result from the subject matter of the dependent claims and from the drawings with the associated descriptions. An exemplary embodiment is explained in more detail below with reference to the attached drawings.BRIEF DESCRIPTION OF THE DRAWINGFIG. 1 shows a schematically illustrated exemplary embodiment of a pliers head of a drilling pliers. FIG. 2 shows an isometric view corresponding to the exemplary embodiment of FIG. 1 FIG. 3 shows according to the invention an adapted tong rivet in the non-deformed state with a corrugation on the outer jacket. FIG. 4 shows a sectional view corresponding to the exemplary embodiment of FIG. 1 along A-A according to FIG. 1 in a greatly enlarged detail of the positive-locking tong rivet connection.Preferred EmbodimentFIG. 1 shows a schematic overall view of a preferred exemplary embodiment as a plan view of a clamp 10 with two clamp legs 1, 2, in particular a drilling clamp. The pliers 10 comprise a pliers head 12 which consists of two opposite pliers jaws 14, 16. The tong legs 1, 2 are connected to one another via a rivet 3. Reference numeral 4 denotes an adapted tong rivet to which a wire clamp 5 is fastened. The wire clamp 5 is made of resilient spring wire steel. Two subsequent gripping regions 18, 20 serve for manual actuation of the pliers 10. the wire clamp 5 runs substantially parallel to cutting edges 22 of the pliers 10, between the two pliers jaws 14, 16. The two pliers limbs 1, 2 are connected to one another in an articulated manner via the rivet 3, wherein the rivet simultaneously assumes a mechanical guiding and bearing function.FIG. 2 shows an isometric view of the tong head 12 according to the exemplary embodiment shown in FIG. 1. As far as the figures correspond, the same reference numerals are therefore also used. In this perspective illustration, the spatial arrangement and structural configuration of the individual components-in particular of the tong rivet 3, of the adapted tong rivet 4 and of the wire clamp 5 fastened thereto-can be seen better. The tong head 12 has the cutting edges 22 on the one hand and gripping surfaces 24 on the other hand, so that the tong 10 can be used as combined tong with a plurality of functions, such as gripping, cutting and twisting, for example. The geometric relationship between the rivet 3 and the additional tong rivet 4 adapted thereto for holding the wire clamp 5 is illustrated plastically.FIG. 3 shows an enlarged illustration of the adapted tong rivet 4 in the non-assembled and undeformed state. This has a structured outer lateral surface 26 with a circumferential corrugation 28. In the assembled state, this corrugation 28 serves to form a positive engagement with the inner surface of a blind bore 30 (see FIG. 4 ) in the rivet 3 shown in FIG. 4 The structure of the outer jacket 26 is designed such that it plastically deforms into the material of the bore wall 32 of the rivet 3 during the assembly of the tong rivet 4 and thereby creates a permanent, play-free, twist-proof and axially positive connection.FIG. 4 shows a sectional illustration along the section line A-A according to FIG. 1 in a greatly enlarged illustration, wherein the focus lies on the region of the positive connection between the rivet 3 and the adapted tong rivet 4 inserted therein. The sectional view illustrates in particular the formation of a structured inner wall of the blind bore 30, for example in the form of a threaded structure or a microtoothing, which engages with the corrugation of the outer jacket 26 of the tong rivet 4. This positive connection securely fixes the tong rivet 4 in the rivet 3 in the axial and rotational direction and ensures the fixed connection of the wire clamp 5.The tong head 12 illustrated in FIG. 1 has two functional regions of pairs of action: a first pair of action for gripping (e.g. wires) with the gripping surfaces 24 of the tong jaw 12 and a second pair of action for cutting with the cutting edges 22. The cutting function, on the other hand, is activated by the bringing together of the two cutters, wherein the wire clamp 5 is arranged in a neutral position between the cutters in the open position. During the closing process, the wire clamp 5 is positively guided over the severed wire ends by the cooperation of the cutters and holds these mechanically firmly as a result of the movement. As long as the pair of active cutting functions remains closed, the cut wire ends remain fixed in a force-fit manner between the wire clamp 5 and the cutting surfaces.The corrugation of the outer jacket 26 of the tong rivet 4 shown in FIG. 3 serves not only for mechanical fastening, but also brings about a permanent, play-free integration of the wire clamp 5 into the tong head by targeted plastic deformation in the material of the blind bore 30, without impairing the movability of the second tong leg 2. The bearing arrangement produced in this way allows a defined, play-free and mechanically reliable function of the cutting mechanism with simultaneously precise positioning of the wire clamp in the working region of the cutting edges 22.List of reference characters1 First pliers limb 2 Second pliers limb 3 Pliers rivet (base rivet for the articulated connection of the pliers limbs) 4 Adapted pliers rivet for fastening the wire clamp 5 Wire clamp 10 Pliers 12 Pliers head 14 First pliers jaw 16 Second pliers jaw 18 First gripping region 20 Second gripping region 22 Cutting edges 24 Gripping surfaces 26 Structured outer lateral surface of the adapted pliers rivet (4) 28 Circumferential corrugation on the outer lateral surface (26) 30 Blind hole bore in the pliers rivet (3) 32 Hole wall of the blind hole bore (30)References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 36 15 280 A1

[0009] DE 26 41 461 B2

[0010] DE 14 78 967 A1

[0011] EP 0 624 433 A1

[0012]

Claims

Wire clamp (5) for fixing loose ends of wires for a clamp (10) for twisting the wires, wherein the clamp has two clamp legs (1, 2) which are connected to one another in an articulated manner via a clamp rivet (3), characterized in that the wire clamp (5) is provided fastened to the clamp rivet (3).Wire clamp (5) for a clamp (10) for twisting wires according to claim 1, characterised in that the clamp rivet (4) has on its outer jacket (26) a holding structure (28) which is in particular corrugated, notched, grooved, napped, knurled and / or rastered.Wire clamp (5) for a clamp (10) for twisting wires according to one of claims 1 or 2, characterised in that the clamp rivet (4) is inserted into a blind bore (30) in a positively locking and plastically deformed manner, so that a plastic positively locking connection is produced between the bore lateral surface and the clamp rivet lateral surface (26), which plastic positively locking connection prevents a relative movement in the radial and axial directions.Wire clamp (5) for a clamp (10) for twisting wires according to one of claims 1 to 3, characterised in that the wire clamp (5) consists of spring steel wire.Wire clamp (5) for a clamp (10) for twisting wires according to one of claims 1 to 4, characterised in that the wire clamp (5) runs parallel to the cutting edges (22) of the clamp (10), between the two clamp legs (1, 2).Pliers (10) for twisting wires, wherein the pliers (10) have two pliers limbs (1, 2) which are connected to one another in an articulated manner via a pliers rivet (3), characterized in that a wire clamp (5) for fixing loose ends of wires is fastened to the pliers rivet (3).Pliers (10) for twisting wires according to claim 6, characterised in that the pliers rivet (4) has on its outer side a holding structure (28), which is in particular formed corrugated, notched, grooved, napped, knurled and / or gridded.Pliers (10) for twisting wires according to one of Claims 6 to 7, characterized in that the pliers rivet (4) is introduced into a blind bore (30) in a positively locking and plastically deformed manner, with the result that a plastic positively locking connection is produced between the bore lateral surface and the pliers rivet lateral surface (26), which plastic positive locking connection prevents a relative movement in the radial and axial directions.Pliers (10) for twisting the wires according to one of claims 6 to 8, characterised in that the pliers rivet (3) forms a fixed bearing with the first pliers limb (1) and a movable bearing with the second pliers limb (2) in order to ensure that the limbs (1, 2) slide without play.Pliers (10) for twisting wires according to one of claims 6 to 9, characterised in that the pliers (10) are provided as combined pliers with a gripping function with gripping surfaces (24) and a cutting function with cutting edges (22).

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