Electric plug connector with bending guard

Abstract

The invention relates to an electric plug connector consisting of a locking element for releasably connecting to a mating plug connector, a housing for receiving at least one cable and at least one contact element, and a bending guard which is made of an elastic material and prevents excessive bending of the connected cable, wherein the bending guard can be used for different cable cross-sections for field assembly.

Description

[0001] The invention relates to an electrical connector with strain relief according to the preamble of independent claim 1.

[0002] Such connectors are needed to connect lines, especially cables for transmitting electrical currents, signals and data, to device connections or corresponding connectors. State of the art

[0003] Typically, various bend protection devices, also known as kink protectors, are used in state-of-the-art technology to prevent the cables connected through the connector from twisting, excessive bending, or, in the worst case, kinking during operation. These stresses can damage the cable, the connector's contact elements, the connector as a unit, or, in the worst case, the connected device. Furthermore, bend protection devices are often also designed to act as strain relief.Strain reliefs provide relief to the connectors, the wires in the cable and the associated contact elements during tensile stress, which can occur unintentionally due to moving elements such as industrial trucks, people or similar circumstances, or due to normal operational movements of a device coupled to the connector, for example a connected machine.

[0004] In most current technologies, bend protection is achieved by molding a corresponding element onto the cable exit of a connector, typically using an overmolding process. However, these methods are relatively expensive and complex. Furthermore, the user / customer cannot install the cable or connector themselves.

[0005] The current state of the art for field-installable connectors mostly uses cable glands. In this method, sealing elements, such as plastic or rubber gaskets, are clamped between the cable and the housing of the electrical connector using a nut with a recess for the cable.

[0006] EP 3 132 506 B1 shows a cable exit for mounting on a cable exit socket of a device, housing or connector. A curable polymer is provided on the inside of the cable exit, which mechanically connects the cable exit, the connector clamp and the cable to be inserted.

[0007] US Patent 2,027,962 A claims a method for manufacturing articles with a plastic composition, at least partially consisting of thermoplastic resin material, comprising manufacturing a preform from the plastic composition and subjecting the preform to heat treatment to cause it to change its physical shape and assume its final shape and to make it heat-stable.

[0008] The current state of the art generally allows for field assembly of connectors with cables to be joined either a professional-looking connection, but only for predetermined cable cross-sections, or a less professional-looking connection, which, however, can be used for different cable cross-sections. The known screw connections or screw seals, on the other hand, can damage the cable or the conductors it contains if used improperly or carelessly.

[0009] The German Patent and Trademark Office has searched the following prior art in the priority application for the present application: DE 10 2014 105 442 A1, CN 108 321 653 A, US 2017 / 0227401 A1, CN 2 842 794 Y, DE 10 2015 219 654 A1 and DE 10 2015 221 898 A1. Task

[0010] The object of the invention is to provide a field-assemblable and visually appealing cable connection to a connector which can accommodate and seal different cable cross-sections.

[0011] The problem is solved by the subject matter of the independent claims.

[0012] Advantageous embodiments of the invention are specified in the dependent claims and the following description.

[0013] The invention relates to an electrical connector comprising a locking element for detachable connection with a mating connector, a housing for receiving at least one cable, at least one contact element, and a bend protection element. The bend protection element is made of an elastic material and prevents excessive bending of the connected cable. A connecting element is arranged between the housing and the bend protection element, wherein the connecting element can be moved from a first state to a second state, the second state being irreversible. The bend protection element is permanently fixed to the cable-side end of the housing by the connecting element as soon as the connecting element is in the second fixing state. Alternatively, the bend protection element irreversibly fixes the bend protection element to the cable, so that the bend protection element is in direct contact with the connector housing.In other words, during the assembly process, the strain relief and the connector are slid onto the cable. The connector is initially in its assembled state. The cable, or at least one conductor within the cable, is then fitted with at least one contact element and inserted into the housing. The connection between the cable and the contact element can, of course, also be made before the strain relief and / or the connector are attached. The connector is then brought to the cable end of the housing, and the strain relief is slid over the connector and onto the cable end of the housing. The connector is advantageously a single piece. The strain relief is also ideally a single piece.After the bend protection is positioned at the cable-side end of the housing, the connecting element transitions from a first state, the assembly state, to a second state, the operating state. In the operating state, i.e., the second state of the connecting element, the connecting element ensures an irreversible connection between the bend protection, the cable, and the housing of the electrical connector. The embodiment provides for the connecting element to be manufactured from at least two components, which are activated by heat and assume the second state, i.e., the operating state. Conveniently, at least one of the components of the connecting element exhibits an adhesive effect as soon as the change of state from the first to the second state is triggered.In this way, in addition to a mechanical connection between the housing, the bend protection, and the cable, a material-bonded connection can be established via the connecting element. An additional material-bonded connection would have the particular advantage of providing more reliable protection against the ingress of foreign substances, such as dust and / or water. Furthermore, the embodiment provides for the change of state of the connecting element from the first state to the second state to be implemented as an irreversible expansion. For this purpose, the connecting element is designed, for example, as an O-ring made of an expanding plastic, such as polyurethane.Similar to applications in the construction industry, a foam-forming polyurethane is selected, for example, which creates a particularly advantageous connection between the components of the electrical connector, i.e., the housing, the cable, and the bend protection. This embodiment appears particularly interesting as a retrofit solution, in which a bend protection according to the invention is applied to a previously manufactured, corresponding housing of an electrical connector, the housing having a thread on the cable side. As soon as the foam, or a similarly expanding material of the connecting element, is activated, it can expand between the threads and the bend protection to form a particularly advantageous connection with a sealing function.

[0014] In a practical embodiment, a change of state in the fastener is triggered by a temperature change exceeding 50°C. It seems particularly advantageous to select at least one component of the fastener that triggers the change of state by heating the fastener to a temperature above 100°C. This temperature change is intended to prevent unwanted activation of the fastener component. The desired temperature resistance is achieved primarily through the use of thermoplastic materials. The temperature required to activate the change of state in the fastener can, in principle, be influenced by the composition of the plastic. To ensure field assembly, a temperature should be chosen that can be reached with minimal effort, for example, using a hot air gun.Furthermore, it seems logical to manufacture both the housing and the bend protection from a material that can withstand at least the temperature required for activating the connecting element without damage.

[0015] An alternative embodiment of the invention proposes an electrical connector comprising a locking element for a detachable connection with a mating connector, a housing for receiving at least one cable and at least one contact element, and a bend protection device. The bend protection device is made of two components that are activated by heat and can thus be transitioned from a first state to a second state, the second state being irreversible. During the second state, the bend protection device is permanently fixed to the cable-side end of the housing.

[0016] The embodiment provides that the bend protection has a fundamentally hollow cylindrical shape, tapering conically from the cable-side end of the housing towards the cable. The bend protection is equipped with recesses that allow and / or enable limited, damage-free bending of the cable. These recesses generally allow for an aesthetically pleasing shape, similar, for example, to an injection-molded bend protection. Furthermore, a similar level of bend protection, or kink protection, is achieved as with an injection-molded bend protection, but with the sealing effect of heat-shrink tubing.

[0017] In one logical embodiment, this change of state of the bend protection is triggered by a temperature change of more than 50°C. It seems particularly advantageous to choose at least one material for the bend protection of the electrical connector whose change of state is triggered by heating the bend protection to a temperature above 100°C. These temperature changes are intended to prevent, in particular, unwanted activation of the bend protection material. This temperature resistance is achieved primarily through the use or combination of thermoplastic materials. In principle, the temperature required to activate the change of state of the connector can be influenced by the composition of the plastic. To ensure field assembly capability, a temperature should be selected that can be achieved with minimal effort, for example, using a hot air gun.Furthermore, it seems logical to manufacture the housing from at least one material that can withstand the temperature required for activating the bending element without damage.

[0018] According to this alternative embodiment of the invention, at least one of the components of the bend protection loses its adhesive effect as soon as the change of state from at least the first state to at least the second state is triggered. In this way, in addition to a mechanical connection between the housing, the bend protection, and the cable, a material-bonded connection can be established by the second component. An additional material-bonded connection would have the particular advantage of providing more reliable protection against the ingress of foreign substances, such as dust and / or water. Furthermore, in addition to the sealing and bend protection effects, strain relief is achieved. This means that the cable and the electrical connector used are less susceptible to damage from tensile stress. These tensile stresses can occur unintentionally, for example, due to an accident.Such loads can also occur intentionally under tension, for example through movements during the operation of a machine.

[0019] Furthermore, a practical design involves shaping the bend protection into an angle. Angles of 45° are particularly suitable. An angle of at least 90° is also advantageous. Other angles may be required depending on the application of the electrical connector. Example of implementation

[0020] An embodiment of the invention is shown in the drawings and is explained in more detail below. The drawings show: Fig. 1a is an exploded view of an electrical connector according to the invention with bend protection; Fig. 1a is a perspective view of an electrical connector according to the invention with an expanded connecting element; Fig. 2a is an exploded view of an alternative electrical connector according to the invention with bend protection; Fig. 2a is a perspective view of an alternative electrical connector according to the invention with an expanded connecting element; Fig. 3a is a perspective view of an electrical connector according to the invention with bend protection according to the invention in a first state; Fig. 3a is a perspective view of an electrical connector according to the invention with bend protection according to the invention in a second state.

[0021] The figures contain some simplified, schematic representations. In some cases, identical reference symbols are used for elements that are the same but may not be identical. Different views of the same elements may be scaled differently. Directional terms such as "top," "bottom," "left," "right," "front," and "back" refer to the respective views and may vary depending on the elements depicted.

[0022] The Fig. 1a Figure 1 shows an electrical connector 1 according to the invention in a partial exploded view. The electrical connector 1 is shown in the Figure 1aThe illustration shows a combination of a locking element 2, a housing 3, and several contact elements 4 arranged therein. The housing 3 is provided with a thread 5 at its cable-side end, so that cable glands commonly used in the prior art can be employed. A connecting element 6 according to the invention, in the form of an O-ring, is arranged between the cable-side end of the housing 3 and a bend protection element 7 according to the invention. The bend protection element 7 is designed as a hollow cylindrical body with an inner diameter on the housing side, which can be guided over the external thread 5 of the housing 3. The connecting element 6 is shown in a first state.

[0023] In the Fig. 1bThe electrical connector 1 according to the invention is shown in an end-assembled representation. The bend protection 7 is guided over a cable 9 which is connected to the contact elements 4 in the housing 3. The bend protection 7 is guided over the thread 5 and, according to the invention, is shown expanded by activation of the plastic of the connecting element 6. Activation is achieved according to the invention by the application of heat, for example, by a hot air gun. Alternatively, another component can be used for activation, which is, for example, arranged in a reservoir in the bend protection 7 or inserted through the cable-side opening of the bend protection 7. According to the invention, activation results in an irreversible expansion of the connecting element 6, so that the connecting element 6 expands into Fig. 1bin a second state, the operating state. Advantageously, the connecting element 6 expands in such a way that at least part of the thread 5 is also sealed by the connecting element 6. In the Fig. 2 The expanded connecting element 6 creates a material-bonded connection between the housing 3 and the bending protection 7.

[0024] The Fig. 2a and the Fig. 2b show a similar structure to the previously mentioned ones. Fig. 1a and Fig. 1b However, instead of an O-ring shaped connecting element 6, a hollow cylindrical connecting element 6' is used. Similar to the connecting element 6, the connecting element 6' can, through expansion, both provide a sealing effect and create a positive or material-locking connection between the cable-side end of the housing 3 and the bend protection 7.

[0025] An alternative embodiment of the invention is described in the Fig. 3aand the Fig. 3b As shown, in this embodiment, the bend protection 8 is designed as a shrinkable molded element. This eliminates the need for a connecting element 6, as shown in alternative embodiments. By skillfully crosslinking the materials in the bend protection 8, for example by electron beam crosslinking, a shape can be achieved that retains its form even after activation of the bend protection 8, for example by the application of heat. This creates a connection between the cable 9 and the housing 3 of the electrical connector 1, which also leaves a visually professional impression. Figure 3aFigure 1 shows the expanded form of the bend protector 8 after electron beam crosslinking, attached to the housing 3 of the electrical connector 1. The cable 9 is surrounded by the bend protector 8. Polyethylene and / or polybutene are particularly suitable materials for this purpose. In its expanded form, i.e., its first state, the bend protector 8 can be guided over the cable-side end of the housing 3, thus covering an existing thread 5. By transitioning the bending element 8 from its first to its Fig. 3bIn the second state shown, the thread 5 can be used as a particularly advantageous fixing of the bend guard 8 to the housing. A further advantage of the bending element 8 shaped in this way is the ability to accommodate different cross-sections of cables 9 with a similar bend guard 9. This means that the cable 9 shown, for example, can have a cross-sectional area of ​​either 10 mm² or 5 mm² and still be accommodated and sealed equally reliably by the bend guard 9 according to the invention. A clever further development provides for the following: Figures 3a and 3b In the illustrated embodiment of the bending element 8, its inner side is coated with an adhesive material. Even more advantageously, a material is used which acquires an adhesive effect when the bending element 8 is activated and transitions from a first state to a second state. Reference symbol list

[0026] 1 Electrical connector 2 Locking element 3 Housing 4 Contact element 5 Thread 6, 6' Connecting element 7 Bend protection 8 Bend protection 9 Cable

Claims

1. An electric plug connector (1), consisting of a housing (3) for receiving at least one cable (9) and a bending protection (7) that is manufactured from an elastic material and prevents the connected cable (9) from bending excessively, and wherein a connecting element (6) is arranged between the housing (3) and the bending protection (7), wherein the connecting element (6) can be transferred from a first state into a second state, wherein the second state is irreversible, wherein the bending protection (7) is permanently fixed to the cable-side end of the housing (3) by means of the connecting element (6) as soon as the connecting element (6) is in the second state, characterized in that the connecting element (6) consists of at least two components that are activated by heat and assume the second state, and at least one of the components of the connecting element (6) develops an adhesive effect as soon as the change of state from the at least first state into the at least second state is triggered, and wherein the change of state of the connecting element (6) from the first state into the second state occurs in form of an irreversible expansion.

2. The electric plug connector (1) according to claim 1, characterized in that a change of state of the connecting element (6) is triggered by a temperature change of more than 50°C.

3. The electric plug connector (1) according to claim 1, characterized in that a change of state is triggered by heating the connecting element (6) to a temperature above 100°C.

4. The electric plug connector (1), consisting of a housing (3) for receiving at least one cable (9) and a bending protection (7) that is manufactured from an elastic material and prevents the connected cable (9) from bending excessively, and wherein the bending protection (8) can be transferred from a first state into a second state, wherein the second state is irreversible, wherein the bending protection (8) is permanently fixed to the cable-side end of the housing (3) as soon as the bending protection (8) is in the second state, characterized in that the bending protection (8) has a fundamentally hollow cylindrical form that tapers conically running from the cable-side end of the housing (3) towards the cable (9) and is provided with cut-outs (10) that to a limited extent allow and / or render possible the cable (9) to bend, wherein the bending protection (8) consists of at least two components that are activated by heat and assume the second state; and at least one of the components of the bending protection (8) develops an adhesive effect as soon as the change of state from the first state into the second state is triggered.

5. The electric plug connector (1) according to claim 4, characterized in that a change of state of the bending protection (8) is triggered by a temperature change of more than 50°C.

6. The electric plug connector (1) according to claim 4, characterized in that a change of state is triggered by heating the bending protection (8) to a temperature above 100°C.

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