This application claims the benefit of the filing date under 35 U.S.C. § 119(a)-(d) of Italian Patent Application No. 102019000004893, filed on Apr. 2, 2019.
The present invention relates to a connector and, more particularly, to a component of a connector preventing heat dissipation or flame propagation from reaching affected areas of the connector.
‘Raster Anschluss Steck Technik’ (RAST) is a modularized connector system widely used in home appliances. RAST connectors are based on regular pitch connection plug technology and are used, next to household appliances, also in automobiles and industrial control systems for electrical connection between electronic components such as wires and circuit boards. Due to the increase of the functions of household electrical appliances, the number of connectors for connecting function modules to the main controller is correspondingly increasing. The standardized and modularized RAST connector system may be integrated with multiple single devices and a plurality of connectors, optimizing installation time and minimizing the risks of errors while minimizing the space occupied on the PCB and the manufacturing costs.
In the appliance global market, RAST and other types of connectors must fulfill specific requirements and pass specific tests which simulate the working conditions within a house appliance. In particular, in order to get the approval of RAST or other types of connector products by the global appliance customers, the nichrome wire test on flammability must be fulfilled. Heat and flames generated inside a connector should not spread from the connector area into the surrounding parts. The nichrome wire test was introduced in the UL standard for different household appliances. Examples of these standards are: UL 749[1] for dishwashers, UL 2157[2] for electric clothes washing machines and extractors and UL 2158[3] for electric clothes dryers. The result of the nichrome wire test depends from multiple factors, which make it a complex test. It is closely related to the geometry and the type of plastic material used for the connector, for the counterpart and for the surrounding parts, the orientation of the connector inside the household appliance and the distance of the surrounding parts above the connector part.
U.S. Pat. No. 8,057,261 discloses a connector with a housing adapted to receive a flag terminal. The connector comprises an L-shaped housing into which the flag terminal can be inserted. The connector is partially insulated by the housing and has a rear opening for inserting the flag terminal. In order to comply with the proposed standards for consumer appliances, the connector has to be fully insulated in order to avoid accidental contact with exposed terminals. Thus, a rear cover is provided that can be mechanically pushed into the rear opening. The rear cover features tabs that are latched onto the respective apertures of the housing. The housing and cover are composed of an electrical insulating plastic, such as nylon. In order to reduce the risk of flame propagation or heat dissipation to the surrounding area, the housing and cover can be composed of flame retardant nylon compound.
A disadvantage of this system is that the cover is an additional part which must be installed by mechanically pushing it into the terminal opening. Also, as the shape of the cavity and the capture mechanism employed can differ for different flag terminals, the shape of the cover must be adapted so that each cover has a design specific to each flag terminal. Additionally, the cover is installed by pushing it into the terminal, meaning that the choice of the material is limited as the material chosen for the cover must be mechanically compatible with the material of the housing. Also, the main function of this cover is to isolate the electric wires, but not the terminal, therefore the flame-retardant features will be relevant only for a limited portion of the connector. Finally, this system has the disadvantage of being intended to be installed by a machine only.
U.S. Pat. No. 9,692,163 discloses a connector including a housing with a rear opening for inserting a terminal into the housing. The housing features tabs enabling a rear cover to be latched onto the housing closing the rear opening. The cover contains a plurality of retaining arms for receiving the tabs. The cover is fitted externally onto the housing and closes the housing after insertion of the terminal. The housing comprises a material that provides the housing with electrically insulating properties. This system does not address the main need of fulfilling the flammability test as the major surface of the terminal is not protected by the cover. Also, this system has a quite complex geometry and construction.
A connector component for a connector includes a plate and a pair of fastening devices freely protruding from the plate and securing the plate to a connector housing. The plate and the fastening devices are made of a metal or plastic material having a higher inflammability resistance than the connector housing and are adapted to extend on more than one of a plurality of external surfaces of the connector housing.
The invention will now be described by way of example with reference to the accompanying Figures, of which:
The present invention will now be more fully described hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that the disclosure will convey the scope of the invention to those skilled in the art.
In particular, although certain features of the exemplary embodiments below will be described using terms such as “top”, “bottom”, “front”, “rear” and “side”, these terms are used for the sole purpose of facilitating the description of the respective features and their relative orientation and should not be construed as limiting the claimed invention or any of its components to a use in a particular spatial orientation. Like numbers refer to like elements throughout the description.
A connector component 100, as shown in
The two plates 101, 102, as shown in
The fastening devices 103 and 104, as shown in
As shown in
In an embodiment, the connector product 120 includes the connector housing 105, a cavity for receiving an electric wire, an insertion slot perpendicular to the wire receiving cavity for receiving a metallic contact, and the connector component 100. In an embodiment, the connector is a power connector. A method of assembling the connector includes the steps: molding the connector housing 105; inserting the metallic contact and inserting the electric wire; and latching the connector component 100 on the connector housing 105 before or after inserting the metallic contact, or before or after inserting the electric wire. The connector component 100 is latched on the connector housing 105 during the appliance assembly.
In another embodiment, a household appliance includes the connector component 100.
During the flammability test on the connector, the area of the connector which is most affected by the heat is identified. The test is performed as described in the UL standard. For example, samples may be subjected to a test current of 11 Amp for 20 minutes induced by an energized nichrome wire coil. A condition of overheating is generated, which will cause melting of the connector housing 105.
The test allows verification that the thermal stresses that will act on the connector within a house appliance are not homogeneously distributed, some portions will be subjected to higher stress, some to lower. For this reason, only some portions, as for example in this case the rear surface 107 and the top surface 110 of the connector housing 105, require shielding from the surrounding by the connector component or cover 100, while some others, like 106, 108, 109, 111, do not need to be shielded. The connector component 100, is made by a material with higher flammability resistance than the connector itself. For example, looking at the component 100 in
The cover, or the flame retardant cover 100, can be made of high thermal resistance polymers, such as polyphenylenesulfide. Other suitable materials are polyamide, or polybutylene terephthalate or polyethylene terephthalate and polycarbonate or any other plastic materials that can prevent heat and flames from spreading from the connector area to the surrounding parts within the appliances. In an embodiment, the connector component 100 is made of a material having a higher inflammability resistance than a material of the connector housing 105. Also other forms can be used, such as liquid crystal polymers. Alternatively metals can also be used. In an embodiment, the connector component or cover 100 can be made of different materials with different chemical-physical properties and thermal resistances.
If a higher surface needs to be covered, the cover 300 of
For situations in which the top surface 110 of the connector does not need a cover, while the sides 108 and 109 can be protected, the cover or component 400 of
A further possible configuration is shown in
The components 100, 300, 400, 500 according to the above-described embodiments can be used to meet the standards for consumer appliances, such as a dishwasher, and should prevent the surrounding parts from catching fire.
The above mentioned embodiments are intended to be illustrative and not restrictive. For example, as discussed for
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Entry |
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Italian Search Report, App No. 102019000004893, dated Dec. 18, 2019, 8 pages. |
Extended European Search Report, Appln. No. 20166608.8-1201, dated Aug. 24, 2020, 8 pp. |
European Patent Office Communication, Application No. 20166608.8-1201, dated Jan. 12, 2022, 6 pages. |
Number | Date | Country | |
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20200321724 A1 | Oct 2020 | US |