APPLIANCE TO THE ELECTRICAL NETWORK

The present invention relates to a connector for the electrical connection of an electrical appliance to the electrical network.

Examples of such electrical or electronic equipment to be connected are generally electric tools, such as a hair dryer, vacuum cleaner, iron, pressure washer, but the main use illustrated in the preferred embodiment is for a hair dryer.

A type of connector for domestic equipment is illustrated in patent US5409403, which describes a connector consisting of a male and a female part capable of rotating relative to each other by 360°. The female connector has a plurality of concentric metal rings and the male connector has similar concentric metal rings which contact when the male is inserted into the female, resulting in the electrical connection. The rings on the female connector and those on the male have a concave profile, so that when the male is inserted into the female, the two parts bind together in the axial direction, while they remain free to rotate relative to each other.

Patent DE19902034 describes a connector comprising a coaxial plug and a corresponding coaxial socket. The coaxial electrical contacts of both the male and female parts are rings which abut each other, creating the electrical contact between the two parts.

Patent EP2258028 describes a device for the electrical connection of domestic appliances or electric tools, comprising a female receptacle provided with two seats and a male connector which can be inserted inside said female receptacle. The male connector is provided with a first means of electrical contact formed by a pin or tip and a second means of electrical contact formed by a ring. Said male connector is provided with a plastic body to which the electrical contacts are fixed.

The tip and ring are concentric to each other, and are removably inserted inside said female receptacle housings so as to allow a continuous rotation of the male connector relative to the female receptacle around the longitudinal axis.

The housings consist of two retention springs of a metallic nature and are essentially cylindrical in shape with a radius which allows the pin or tip and ring to be inserted and disengaged therefrom and have adequate elastic properties.

The applicant has observed that in the connectors described above, the female contacts are generally cylindrical in shape and accommodate the male so that the physical and electrical contact between the male and the female is 360°.

Although ensuring a good reliability of the electrical connection, this results in significant friction between the male and female when rotating relative to each other. Furthermore, the electrical contact surface between male and female is a significant area which generates an equally significant amount of heat, which can be difficult to control in an electrical appliance.

Such connectors are, for example, used to connect the power cable of a hair dryer, which when used especially professionally by a hairdresser, is rotated very frequently; in essence, having the cable free to rotate around its axis with respect to the hair dryer when the latter is being handled prevents the cable from twisting, and knots from forming along the same.

Therefore, if the aim is to make a rotating connector, i.e., to allow free rotation at will between the male and the female and at the same time ensure a reliable electrical connection between the two parts, connectors with cylindrical contacts are not an optimal choice. Since the friction is distributed overthe entire cylindrical surface of the annular contacts, it becomes relevant for the long-term reliability of the electrical connection.

The present invention is intended to overcome the aforementioned drawbacks by proposing a connector for the electrical connection of an electrical appliance to the electrical network having the characteristics of the attached claim 1.

The characteristics and advantages of the present invention will be clearer and evident from the following illustrative and non-limiting description, of an embodiment of the connector, with reference to the attached figures which illustrate respectively:

• figure 1 depicts the connector in perspective and exploded view according to the present invention;

• figure 2 depicts the connector in perspective view with the rotating body assembled and the annular element disassembled according to the present invention;

• figure 3 depicts the connector in perspective view with the rotating body assembled and the annular element partially coupled to the rotating body according to the present invention;

• figure 4 depicts the connector in perspective view fully assembled according to the present invention;

• figure 5 depicts the connector inserted in a portion of the handle;

• figure 6 depicts the connector inserted in the end part of a handle formed by two shells, of which one of the two shells has been omitted.

The connector according to the present invention can be used in all electrical equipment with a handle or grip which is frequently moved by the operator during use, who consequently also moves and/or rotates the power supply cable.

Advantageously, the connector of the present invention can be used in equipment where the power supply cable enters them from the handle/grip, or close thereto. Examples of such types of equipment are a hair dryer, a hair straightener, an iron, a pressure washer, etc.

With reference to the above-mentioned figures, the rotating electrical connector comprises a rotating body 2, which is associated with such a power supply cable, and an annular element 3, which surrounds such a rotating body and which, when coupled thereto, determines the electrical connection therebetween through respective electrical contacts. The rotating body 2 and the annular element 3, when assembled together, are capable of rotating relative to each other around a longitudinal axis X of the rotating body.

The rotating body 2 is made of an electrically insulating material (i.e., a plastic material), is elongated in shape and comprises a first DI and a second D2 electrical contact, both of which appear as discs (a first disc DI and a second disc D2) of electrically conducting material (i.e., metal), preferably concentric and overlapping. Such contacts are made near the head 21 of the rotating body, which is essentially cylindrical in shape. Preferably, such discs are superimposed one on top of the other and may be interspersed with a spacer 22 of insulating material, also disc-shaped. Moreover, such discs are advantageously of equal radius.

The discs DI and D2 comprise respective electrical connection cylinders Cl and C2 inside which the electrical wires Fl and F2 (phase and neutral) of such a conventional power supply cable are inserted, which are positioned vertically in contact with the lower surface of the respective disc and extend downwards inside suitable communication channels obtained inside the rotating body 2, in which the aforementioned phase and neutral wires of the cable also pass, so as to exit from a lower tail 23 of the rotating body itself.

Such a tail 23 is essentially truncoconical, and the arrangement of the channels therein also allows centring the connector of the discs DI and D2 in the rotating body during assembly.

The electrical wires are fixed inside such cylinders Cl and C2 by 'crimping', which is done by mechanically crushing the tubular, so that the cable remains clamped on the connector due to the pressure (crushing) exerted. This ensures a good electrical contact, which is superior to what welding would ensure. The crimping operation is irreversible, meaning that once the connector is applied to the end part of the cable, it is impossible to remove it without damaging the cable and connector. A conventional grommet (not shown) is then moulded on such a portion of the tail.

The head 21 of the rotating body 2 comprises at its upper end an annular groove 211 and at its lower end, in the junction area with the tail 23, it comprises an annular projection 212. Such a groove determines the correct positioning of the annular element 3 when coupled around such a rotating body.

The annular element 3 is also made of an electrically insulating material (i.e., a plastic material) and comprises a pair of jaws 31 and 32, preferably of a substantially rectangular radial shape, which close on the rotating body 2. Inside at least one of the two jaws, a third Pl and a fourth P2 electrical contact are made which, when the jaws are coupled to the rotating body, go to abut the corresponding first and second electrical contact DI and D2 of the rotating body itself. Specifically, the electrical contacts Pl and P2 of the jaws appear as pliers grasping the respective disc, making a sliding contact, whereby an upper arm of the pliers Pll or P21 rests on the upper surface of the disc Dll or D21 and the lower arm P12 or P22 abuts the lower surface of the same disc D12 or D22. The arms of the pliers have inverse convexity relative to each other so that their ends are normally open to facilitate the insertion of the edge of the respective disc.

In the fulcrum area, the pliers are shaped so as to facilitate their interlocking fixing in the jaw body and, furthermore, have electrical connection terminals T1 and T2 emerging from conduits 311 and 312 obtained vertically in the jaw. The arrangement of the ducts in the jaw also determines the correct positioning of the pliers Pl and P2 in relation to the discs DI and D2 when assembling the connector.

The jaws preferably comprise a groove 33 in their upper surface, which when assembled on the rotating body corresponds with the upper annular groove 211, determining the correct positioning and assembly of the connector and optimal electrical contact between the pliers and the discs.

The groove 211 prevents the inadvertent vertical disassembly of the connector, simultaneously ensuring the comfortable rotation of the rotating body between the jaws.

Once the rotating body 2 has been assembled with the annular element 3, the connector can be inserted in a special seat of the handle M of the electrical equipment, or more generally in the body of the electrical equipment. The annular element is locked in the handle while the rotating body can rotate freely around such a junction axis X, together with the power supply cable of the equipment, without causing kinking.

The connector as described above allows to obtain a stable electrical contact (even over time) and at the same time ensures sufficient freedom of rotation between the two parts. In fact, the pliers ensure a stable electrical contact with the discs, resulting in low friction between the parts sliding with each other and thus limited wear over time. Lastly, the constraint of the wires by 'crimping' also improves the quality of the electrical contact.

The connector can be assembled inside the equipment handle as illustrated in figures 5 and 6, or elsewhere on the equipment.

The handle M, or the insertion point in the equipment, is formed by two shells, for example semi-cylindrical (of which only one Ml is shown in figure 6) which have ribs MR through which the annular element 3 is locked therein. Such ribs also determine the formation of air passages between such an element and the inner surface of the shell, which promote heat exchange with the outside of the handle so as to maintain the electrical connector at an optimal temperature. The rotating body 2 is imprisoned in the handle through its annular projection 212, which inserts into a special annular seat NA obtained on both shells of the handle. Such a seat favours and does not constitute an impediment to the rotation between handle M and rotating body 2.

The ease of rotation between the rotating body 2 and the annular element 3 made integral with the handle M or the insertion point in the equipment prevents the kinking of the power supply cable, safeguarding the maintenance of the electrical connection and the stability of the operating temperature inside the annular element 3.