A BLADE CONNECTOR STRUCTURE FOR ELECTRICAL APPARATUS

Abstract: A blade connector structure (1) for the formation, in an extremely simple and rapid manner, of the connection of an electrical appliance both to a supply cable (2) and to an earthing point. The blade connector structure (1) essentially comprises an elongate body (2) made of insulating material, provided with an elongate axial median projection (3) ex­ tending from one end and on either side of which are fixed corresponding connecting conductor elements (5) each hav­ ing a pair of blade contacts. Spaced from these conductor elements on the insulating body (2) is fixed a suitably shaped small metal plate (9) provided with means (10, 11) for retaining the earthing wire (12) and means (13, 20) for its anchorage to the casing (18) of the appliance to which it is fitted.

Description: The present invention relates to a blade connector structure which can be fitted to an electrical appliance, in particular to a domestic electrical appliance incorporating an attachment by which preliminary connection of the supply cable and earthing of the metal casing thereof can be achieved. As is known, to avoid the possible risks of electrocution domestic electric apparatus in general requires an effective earthing connection of the metal housing or casing. For this purpose there is currently generally provided on the casing itself a captive screw or the like to which the terminal part of the earthing wire is anchored by means of a nut and an associated washer. The said arrangement obviously can involve some difficulties for its correct performance, and furthermore involves not insignificant times for connection of the said earthing wire. The document DE-U-8 226 692 discloses a blade connector structure for connecting an electrical supply cable to the internal wiring of an electrical appliance, it comprises an elongated body of insulating material having at one end an elongated projection extending axially and laying in a longitudinal median plane to either side of which are fixed respective conductive connector elements each having blade contacts. The reference US-A-3 188 596 discloses and electrical connector structure wherein blade connectors are used and, spaced apart from the connectors there is fixed a shaped metal plate provided with means for retaining an earthing wire and means for electrical connection thereof to the casing of the electrical apparatus to which the connector is to be fitted. The object of the present invention is that of eliminating the previously indicated disadvantage by providing a blade connector structure which is able to simplify the supply and, in particular the connection between the casing of an electrical appliance and the earth connection in the greatest possible manner. According to the present invention, there is provided a blade connector structure for connecting an electrical supply cable to the internal wiring of an electrical appliance, having the features of the main claim. A particular advantage of the invention is that of providing a blade connector structure which allows the preliminary connection of the supply cable, complete with the said earthing cable to be effected. Another advantage of the present invention is that of providing a blade connector structure which is easy to fit with a minimum of substantially elementary operations from the outside of the casing of a domestic electrical appliance or the like. A further advantage of the present invention is that of providing a blade connector structure which is constructionally simple and of great reliability. Two embodiments of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic side view of a connector structure formed as an embodiment of the invention; Figure 2 is a plan view from above of the same connector structure; Figure 3 is a plan view from below of the same connector structure; Figures 4 and 6 are two exemplary apertures which may be formed on the metal casing of apparatus to be supplied with electricity, for receiving the structure of the present invention; Figure 5 is a rear view of the same structure when fitted in an aperture such as that illustrated in Figure 4 and connected to the said casing; and Figure 7 is a plan view from above of a second embodiment of the invention. Referring now to the drawings, the connector structure of the invention, generally indicated 1, comprises a body 2 of insulating material having an elongate conformation with a flat plate-like longitudinally extending projection 3 at one end lying in a median axial plane, and a generally disc-like transversely enlarged head portion 4 at the other end with a central coaxial aperture for receiving an electrical connector cable 21 of conventional 3-core type having two current-carrier wires 16 and an earthing wire 12. This elongate body is shaped in such a way as to define, on opposite sides of the said median projection 3, corresponding seats to receive blade contacts 5 to which the current-carrier wires 16 are connected by means of a clamping screw 6. On the same elongate body 2 there is formed a substantially flat portion 7 provided with elastically deformable upwardly extending projections 8 which are able to retain a metal plate 9 provided with corresponding apertures 10. This plate, in particular, has a threaded hole for the engagement of a clamping screw 11 for forming an electrical connection between the earthing wire 12 and the small plate 9 itself. This plate, moreover, is provided with one or more right angle projections 13 provided with special small teeth having an enamel-breaking formation to make certain of the earthing contact to the casing of the apparatus the exterior of which is usually coated in enamel or other protective coating. The said right angle projections 13 extend orthogonally of the axis of the body 2 generally tangentially of the disc-like head end portion 4 thereof. In the region adjacent the head end 4 of the body 2 this latter has a substantially rectangular or oval transverse section matching the shape of an aperture 17 in a panel 18 of the casing of the electrical appliance to which the connector is to be fitted as shown in Figures 1,2 and 5. In practice, the connector 1, with the supply cable 21 preliminarily fitted thereto and the earth wire 12 connected to the plate 9 by the screw 11, is inserted into the aperture 17 in the casing 18 of the domestic electrical appliance. The panel 18 is also formed with two through-holes 19 to receive the shanks of corresponding, preferably self-tapping screws 20 by which the right angle brackets 13 of the small plate 9 can be connected to the casing panel 18 thereby securing the connector 1 to the panel 18 and at the same time connecting the earth wire 12 to the casing panel 18. In the embodiment illustrated the connector 1 can be mounted and dismounted directly from the exterior of the apparatus. The body 2 is provided, close to the disc-like enlarged head end 4, with resilient teeth 15 which serve to retain the body 2 in position when fitted into the aperture 17.

Claims: A blade connector (1) for connecting an electrical supply cable (21) to the internal wiring of an electrical appliance, comprising an elongate body (2) of insulating material having at one end an elongate projection (3) extending axially and lying in a longitudinal median plane to either side of which are fixed respective conductive connector elements (5) each having electrically conductive blade contacts, said body (2) having a substantially flat top portion (7), said flat top portion being provided with a plurality of deformable projections (8) for retaining a metal plate (9) for mechanically fixing and electrically earthing said connector, and provided with first screw means (11) for clamping an earthing wire (12) and second screw means (20) for removably electrically engaging said plate and connector in an opening (17) of a casing (18) of said electrical appliance, said elongate body (2) further including,at the opposite end from said elongate projection (3), an enlarged disc-like head portion (4), clamping screw means (6) being provided for connecting the ends of current-carrier wires (16) to said connector elements (5), said plate (9) having a threaded hole for engagement of said first screw means (11) for forming an electrical connection between said earthing wire (12) and said plate (9), said plate (9) further comprising right-angle projections (13) having holes therethrough for receiving said second screw means (20), said second screw means (20) being operable from without said appliance to electrically and mechanically connect the plate (9) to the casing. A blade connector according to Claim 1, characterized in that said insulating body (2) has, adjacent the disc-like head end portion (4), a part having a substantially rectangular transverse section from opposite faces of which project respective resilient deformable teeth (15). A blade connector according to Claim 1, characterized in that said second screw means (20) for electrically connecting said plate (9) to said casing (18) of said electrical appliance include shaped teeth having an enamel-breaking function. A blade connector according to Claim 1, characterized in that said projections (13) of said metal plate (9) comprise two tongues (13) bent at 90° to the plane of the plate and laying close to a threaded hole in which said earthing wire (12) is anchored. An electrical appliance provided with a blade connector (1) according to any preceding Claim, characterized in that the electrical appliance has in said casing two throughholes (19) closely adjacent said aperture (17) to receive the shanks of corresponding self-tapping screws whereby said metal plate (9) is connected to the casing panel (18) itself. An electrical appliance according to Claim 5, characterized in that said aperture (17) in the casing panel (18) has two diametrically opposed cavities to further facilitate insertion and removal of the body (2) of the connector (1) from outside the appliance.

Inventors: GELATI, BRUNO
Applicants: ELETTRO GIBI S.P.A.
Application year: 1987
Main classification: H01R13
IPC codes: H01R13