CONNECTION DEVICE FOR ELECTRICALLY CONTACTING AN ELECTRICAL APPLIANCE

Description

[0001] The invention relates to a connecting device for electrically contacting an electrical device with a power plug, a power cable, the power cable having a neutral conductor and a phase conductor, and a device connection device. The power plug is arranged at one end of the power cable and the device connection device is arranged at another end of the power cable or centrally. The device connection device has a clamping spring and can be mounted on a housing of the electrical device. Furthermore, the invention relates to an electrical device with a connecting device.

[0002] Connecting an electrical device to a suitable power plug is a complex task for electrical device manufacturers, as the plugs must be adapted to the respective electrical connections in each country. Furthermore, a grounding contact must also be established. Such grounding contacts in the housing of an electrical device are typically implemented by screwing or plugging.

[0003] Screwing in the cable requires a lot of effort, and the connection can come loose during insertion. Another disadvantage is that screwing in the cable loses its clamping force because the pressure of the screw on the cable causes the cable material to melt over a longer period of time. This can disrupt the grounding of the electrical device in question during its service life, which poses significant hazards.

[0004] Installing a grounding conductor by plugging in a plug requires additional components within the electrical device, namely a plug-in terminal or a similarly designed receptacle for the plug. For example, if the housing of the electrical device is to be grounded, a plug-in terminal must also be provided on this housing, for example, by welding or screwing.

[0005] Furthermore, the design of such contact systems for electrical devices, particularly their mains connection, is disadvantageous from an electromagnetic compatibility perspective, since the protective conductor is routed through the housing wall into the device without being effectively contacted at the point where it penetrates the housing. This means that the Faraday cage effect of such a device's housing is not utilized.

[0006] DE 2020 13101698 U1 discloses a connecting device for electrically contacting an electrical device with a power plug, wherein a grounding conductor and / or a ground connection can be electrically contacted by means of a plug on a plug lug of a housing plate. EP2978075A2 discloses a connecting device according to the preamble of claim

[0007] The object of the invention is to improve the state of the art.

[0008] The problem is solved by a connecting device for electrically contacting an electrical device with a mains plug, a mains cable, the mains cable having a neutral conductor and a phase conductor, and a device connection device, the mains plug being arranged at one end of the mains cable and the device connection device being arranged at another end of the mains cable or centrally, and the device connection device having a clamping spring and being mountable on a housing of the electrical device, the earthing conductor being electrically contacted with the housing by means of the clamping spring designed as a tongue loaded by means of elastic deformation, so that when the device connection device is mounted on the housing of the electrical device, a force is exerted on the housing by means of the clamping spring and earthing of the housing sheet receptacle is made possible by means of the housing sheet receptacle.

[0009] The connection device according to the invention allows the user to establish the main protective conductor connection from the mains protective conductor to the device housing with a single movement. For this purpose, the connection device is pre-prepared in such a way that only a clamping spring allows contact with the protective conductor.

[0010] According to the invention, the grounding conductor is clamped to the housing of the electrical enclosure only with the clamping spring, so no additional sheet metal or cover is required. The clamping spring can connect the stripped strands of the mains protective conductor to the metal housing of the electrical device without the need for an additional cover.

[0011] This significantly reduces the number of steps required by electrical device manufacturers. Another advantage is that insertion, for example, only occurs in a single direction. Any additional locking action through a separate movement in a different direction, such as rotation, is therefore not always necessary.

[0012] Alternatively, locking can also be achieved by a separate movement, such as rotation or angular movement.

[0013] The following terms are explained here:

[0014] "Electrical contact" of an electrical device refers to the connection of the electrical device to an electrical supply network, for example, to an AC power supply. Electrical contact particularly includes the connection of a phase conductor and a neutral conductor, but can also mean connection to a three-phase AC power supply. In this case, for example, there are three phase conductors and a common neutral conductor. Furthermore, electrical contact includes the connection of an earthing conductor, also called a protective conductor, which serves as the protective conductor for the electrical supply of the electrical device and must contact metallic components of the electrical device, such as the housing, to prevent danger to persons in the event of a malfunction of the electrical device.In such a case, the earthing or protective conductor discharges fault voltage so that an electric shock to a person is mitigated or avoided as best as possible.

[0015] A "housing" is a hollow body enclosing the electrical device, which, in particular, prevents or impedes mechanical and electrical access to the device's internal components. In particular, such a housing within the meaning of the present invention is a sheet metal housing, a metal housing, or another electrically conductive housing. Such a housing is then subject to the obligation to contact the electrical device's grounding or protective conductor.

[0016] A "mains plug" can be any standardized or non-standardized connection option that includes an electrical contact for connecting such an electrical device to a country-specific power supply network. For example, such a plug is a so-called Schuko plug, a CE plug, or a three-phase plug with a connected load of 16 amps or 32 amps.

[0017] A "power cord" is, for example, the connecting cable of an electrical device, in which several strands or cables are arranged to connect the power plug to the electrical device. For example, this power cord includes one or more phase conductors, a neutral conductor, and an earthing or protective conductor.

[0018] A "device connection device" is, for example, a terminal, a cable bushing, or a cable grommet with a means of connection to a device housing, as well as equivalent devices. For example, a device connection device is a combined cable bushing that also allows the cable to be mounted on a device housing with strain relief.

[0019] A "clamp spring" can be, for example, a bent sheet metal strip, a spring-loaded tongue, or another device by means of which a force or pressure can be exerted through elastic deformation. In particular, this clamp spring can be made of metal, thus enabling electrical contact. Such a clamp spring can serve as a contact element on the housing of an electrical device or can press a grounding or protective conductor directly against such a housing to establish electrical contact.

[0020] A "housing sheet" is, for example, a steel sheet, an aluminum sheet, or a sheet made of another conductive material. The housing sheet serves, in particular, to close an opening in the housing of an electrical device as a component of the connection device, particularly after the connection device has been installed. Such a housing sheet can therefore also be made of an identical or similar material and, for example, with an identical or similar sheet thickness to the housing of an electrical device. Such a "housing sheet" can also be referred to as an "insertion sheet" or "cover."

[0021] A "housing sheet receptacle" is, for example, a recess, an opening, or a slot within the housing of an electrical device. The housing sheet receptacle is designed, for example, so that a housing sheet can be accommodated in this housing sheet receptacle. In particular, the housing sheet receptacle is designed to correspond to the housing sheet and / or to the device connection device, so that electrical contact is also established, for example, with the housing sheet or the protective conductor.

[0022] A "crimp contact" can be any device suitable for accommodating a cable, conductor, stranded wire, or other end portion of an electrically conductive system and for electrically contacting individual components through permanent plastic deformation. In particular, such crimp contacts are contacted using a special tool, namely crimping pliers or the tool of a crimping press.

[0023] "Grounding" refers to the sum of all means and measures for earthing, i.e., for diverting fault voltages or currents from electrical devices via the mains protective conductors and / or the earthing equipotential bonding, for example, to the star point of the power supply transformer. Such grounding serves to equalize potentials and also to prevent the flow of a tripping or fault current to shut down faulty devices and networks, thus protecting living beings and devices.

[0024] Grounding diverts electrical voltage or potential in such a way that, at best, it has no effect on a person, or at least a greatly reduced effect. Grounding is usually achieved using a grounding or protective conductor, which is then grounded, for example, via a power plug with grounding or protective contacts.

[0025] To ensure particularly secure and easy contact with the grounding conductor, i.e., particularly simple and safe implementation of the grounding connection, the grounding conductor is stripped in the middle or in an area associated with the other end. This creates a contact point, and this contact point is electrically connected to the housing sheet or a component of the housing of an electrical device. Alternatively, the stripped point can also be directly connected, for example, with a clamping spring, to an electrically conductive part of the housing of an electrical device.

[0026] In addition, grounding can be established before the connection device is mounted on the housing panel. This eliminates the need for separate contact with another stranded wire. Contact can be established via a crimp connection attached to the housing panel or a cover, or directly via a contact spring.

[0027] A "contact point" is, for example, a stripped area of ​​the grounding conductor, an area where the insulation of the grounding conductor is severed or pierced, or any other possibility of electrically contacting an area within the grounding conductor, such as a stranded wire or a wire. In particular, this can also be an area of ​​insulation partially severed with a quick connector to connect the conductor to the quick connector.

[0028] In one embodiment, the power cable and the housing sheet are connected to one another by means of a fastening element, in particular by means of an injection-molded element, so that the device connection device is thereby formed.

[0029] Such an injection-molded element can, for example, also serve as a feedthrough for a power cable, so that only the component formed by the injection-molded element needs to be installed as a device connection device. All necessary contacts can be made beforehand within or through this injection-molded element, eliminating the need for further assembly work.

[0030] A "fastening element" is, for example, an injection-molded plastic component, a component with another electrically insulating design, or a flange that combines multiple functions. In particular, such a fastening element is a component that serves for mechanical mounting on a housing of an electrical device and simultaneously performs the functions according to the invention.

[0031] An "injection-molded element" can be any component made by injection molding. For example, this component is then manufactured using the injection molding process from a polyamide, a polyethylene, or another plastic that is thermoplastic or semi-thermoplastic and, in particular, electrically non-conductive.

[0032] Furthermore, such an injection-molded element can also be manufactured separately from, for example, an anti-kink strain relief grommet in the form of one or more assembly parts in a separate manufacturing process and mounted on the power cable complete with the earthing elements.

[0033] In order to reliably implement the connection device, the device connection device has a corresponding housing sheet counter-receptacle so that the device connection device can be positioned in a defined manner in the housing sheet receptacle.

[0034] This design ensures that the device connection device, with its housing plate counter-receptacle, is designed to directly match the housing plate receptacle. This ensures error-free assembly. Furthermore, with regard to electromagnetic compatibility, it allows for the formation of a closed Faraday cage with the housing, in which, in particular, the housing plate is precisely integrated.

[0035] In a further embodiment, the clamping spring is designed such that the clamping spring releasably and firmly clamps the device connection device to the housing sheet receptacle, so that there is an electrical contact between the housing sheet and the housing sheet receptacle.

[0036] This design enables particularly secure contact.

[0037] In order to easily connect the power cable, in particular the neutral conductor and the phase conductor or several phase conductors within the electrical device, the power cable of the electrical devices is stripped on the inside so that the earthing conductor, phase conductor and neutral conductor are present as stranded wires.

[0038] In addition, the individual strands, such as the phase conductor, the neutral conductor and of course also the earthing conductor or protective conductor, can have a plug or a contact plug at their end, with which the internal electronics or other functional elements can also be electrically contacted.

[0039] In addition, the object is achieved by an electrical device according to claim 8, which comprises a connection device according to one of the previously described embodiments.

[0040] Such an electrical device can be designed to be easy to install and advantageous for quality assurance using the connection device. The connection device allows installation in a single step and without additional tools, thus virtually eliminating installation errors, which would be particularly critical and dangerous when installing the grounding system.

[0041] The invention will be explained in more detail below using an exemplary embodiment. Figure 1a perspective view of a cable entry (in a partial housing receptacle, in a slide-in position, Figure 2a further perspective view of the cable entry from Figure 1Figure 3 shows the cable entry with a separate housing sub-holder, and Figure 4 shows a perspective view of a slide-in plate. Figure 5 shows a cable entry with a direct clamping spring and a crimp connection, and Figure 6 shows a cable entry with a direct clamping spring.

[0042] A cable feedthrough 101 comprises a cable 103 and a housing insert contact 102, with the stranded wires 109, 111 located in the cable 103 being led out stripped on one side of the housing insert contact. The housing insert contact 102 is formed by an insert plate 105 and a contact clamping spring 107, which are secured by an injection-molded holder 117. The insert plate has a crimp connection web 123 and a crimp contact 125, with the insert plate 105, the crimp connection web 123, and the crimp contact 125 being integrally manufactured from a single metal sheet.

[0043] In addition, the injection-molded holder 117 has a guide gap 119 on both sides. Side parts of the housing receptacle (shown schematically here as cutout 121) can be guided through this guide gap 119.

[0044] A grounding wire 111 has a stripped center section 115 of the grounding wire 111. The grounding wire 111 is led out of the cable and is bent toward the insertion plate 105 in such a way that the crimp contact 125 can be electrically connected to the stripped center section 115 of the grounding wire 111 using crimping pliers. After crimping, the stripped center section 115 is electrically connected to the insertion plate 105.

[0045] Both the earthing strand 111 and the strands 109 for the phase and neutral conductors have a plug connection 113 at their end.

[0046] In this case, the housing insert contact 102 is inserted into the cutout 121, so that the contact clamping spring 107 is inserted into the cutout 121 in a lower area, so that the clamping spring clamps both the insert plate 105 and the cutout 121. Thus, the insert plate 105 serves both as a cover for the housing and as a conductor for the grounding wire 111.

[0047] The contact clamping spring 107 is suspended in the insertion plate 105 and held by the injection-molded holder 117.

[0048] Once the cable entry 101 is connected to an electrical housing, the plug connections 113 of the strands 109 and the grounding strand 111 can be connected to the internal electrical system of the electrical device.

[0049] Furthermore, the cable gland 101 ensures that the cable 103 is mounted with strain relief, directly in the same way as the cable gland is attached to the housing.

[0050] In an alternative ( Figure 5 ) the earthing, namely the contact of the earthing wire 111 as a protective conductor directly to the housing, is realized as follows:

[0051] The cable gland 101 with strain relief is inserted into the cutout 121 of a device housing as described above. The grounding wire has a stripped central portion 115, which is directly connected to the contact clamp spring 107 on the cutout 121 of the housing sheet metal, thus providing an electrically conductive connection.

[0052] The grounding wire 111 is also attached to the crimp connection bar 123 with the crimp contact 125. This attachment can be achieved either with a grounding wire stripped at this point or with a grounding wire still insulated. Even if no electrical contact is made at this point on the crimp contact 125, the electrical contact of the grounding wire 111 is ensured by the contact clamp spring 107.

[0053] If the ground wire 111 on the crimp contact 125 is also stripped, double contact with the cutout 121 of the device housing is ensured.

[0054] In another alternative ( Figure 6) the cable entry 101 has no crimp connection web 123 and no crimp contact 125 on the insertion plate, so that contacting of the earthing wire 111 by means of the clamping spring 107 is effected by pressing the stripped middle part 115 of the earthing wire 111 onto the cutout 121 of the housing plate.

[0055] In each of the cases shown, the cable 103 is mechanically held in the housing of an electrical device by the cable bushing 101 and at the same time is provided with a strain relief, whereby the electrical contact of the earthing or the protective conductor is ensured by means of the insert plate 105 or the contact clamping spring 107. List of reference symbols

[0056] 101Cable entry with strain relief 102Housing insert contact 103Cable 105Insert plate 107Contact clamp spring 109Wire 111Grounding wire 113Plug connection 115Stripped center section 117Injection-molded holder 119Guide gap 121Cutout 123Crimping connection bar 125Crimp contact

Claims

1. Connection device (101) for electrically contacting an electrical appliance with a mains plug, a mains cable (103), wherein the mains cable has an earthing conductor (111), a neutral conductor and a phase conductor, and an appliance connection unit (102), wherein the mains plug is arranged at one end of the mains cable and the appliance connection unit is arranged at another end of the mains cable or in the centre and the appliance connection unit has a clamping spring (107) and can be mounted on a housing of the electrical appliance, characterised in that the earthing conductor is connected to the housing in an electrically contacting manner by means of the clamping spring designed as a tongue loaded by elastic deformation, such that when the appliance connection unit is mounted on the housing of the electrical appliance, a force is exerted on the housing by means of the clamping spring and earthing of the housing plate receptacle is made possible by means of the earthing conductor.

2. Connection device according to claim 1, characterised in that the earthing conductor is stripped of insulation in the centre or in an area assigned to the other end, such that a contacting point is present and this contacting point is connected to the housing directly or via an insertion plate in an electrically contacting manner.

3. Connection device according to any one of the preceding claims, characterised in that the mains cable and the appliance housing plate are connected to one another by means of a fastening element, in particular by means of an injection moulding element (117), such that the appliance connection unit is formed thereby.

4. Connection device according to any one of the preceding claims characterised in that the appliance connection unit has a corresponding mating housing plate receptacle (119) such that the appliance connection unit can be positioned in a defined manner in the housing plate receptacle.

5. Connection device according to any one of the preceding claims, characterised in that the clamping spring firmly connects the appliance connection unit to the housing plate receptacle in a releasable clamping manner, such that there is electrical contact between the housing plate and the housing plate receptacle.

6. Connection device according to any one of the preceding claims, characterised in that the mains cable is bare on the inside of the electrical appliance such that the earthing conductor, phase conductor and neutral conductor are stranded.

7. Connection device according to any one of the preceding claims characterised in that the earthing conductor, the phase conductor and / or the neutral conductor each have a contact plug (113), such that an electrical connection to an appliance electrical system can be realised in a pluggable manner.

8. Electrical appliance having a connection device according to any one of the preceding claims.