FR2707430A1 - Electrical connection device, especially for a cylindrical terminal - Google Patents

Abstract

An electrical connection device supplies power to a terminal 1 of a heating element (resistance). The device comprises a connection socket 4, including a series of little strips 8a-8e, and a crimping unit 3 including two pinching members 5, 6. Application to the electrical supply of heating elements of domestic electrical appliances or industrial appliances.

Description

ELECTRICAL CONNECTION DEVICE, ESPECIALLY
FOR CYLINDRICAL TIP
The invention relates to an electrical connection device, in particular for a cylindrical end piece.

 Currently used in known household appliances such as electric stoves, dishwashers, washing machines, dryers or the like, electrical resistances in which an electric current flows with an intensity of the order of several amps heating this resistance by Joule effect cyclically at temperatures above 200 "C.

 These known electrical resistors have at least one cold end intended for electrical connection generally in the form of a cylindrical end piece. On this cylindrical end piece, attempts have been made in the past to forcibly thread a supply connector in the form of a split cylinder made of elastic material. However, as a result of thermal cycling, the aforementioned connector gradually lost its elastic characteristics: this adversely affected the quality and reliability of the electrical connection.

 Because of this drawback, it is now usual to solder to the cold end of a resistor to supply a male tab of an electrical connector intended to cooperate with a female lug of known type, or to directly crimp an electrical supply contact. on the aforementioned cylindrical cold end when the latter has a small diameter of the order of 2 mm.

 The object of the invention is to improve the electrical supply of cylindrical end pieces, in particular cylindrical end pieces of heating resistors, by allowing direct connection by plugging in without modification, welding or additional crimping on these cylindrical end pieces.

 The subject of the invention is an electrical connection device, in particular for a cylindrical end piece, capable of supplying an electrical heating resistor comprising at least one substantially cylindrical cold end, characterized in that the device comprises a connection socket comprising a series of strips arranged alternately on either side of the endpiece to be clamped.

According to other additional features of the invention
- The device comprises a crimping block with a first clamp for a central conductor, a second clamp for the peripheral insulator and a recess provided to define a stop for driving in the peripheral insulator
- The connection socket has two raised edges extending longitudinally in the direction of insertion;
- the raised edges constitute mechanical stiffeners and thermal radiators, so as to homogenize the temperature and to avoid any permanent deformation resulting from thermal cycling
- each strip has a general V shape with two curved parts in tangential contact with the end piece
- the tangential contact is made according to a generator in the case of a cylindrical tip
- the tangential contact is carried out according to a specific zone
- the curved parts include a chamfer or an engagement slope of the end piece;
- the curved parts have a part slightly inclined relative to the direction of insertion
- the curved parts comprise at least one anchoring edge preventing the withdrawal of the endpiece.

The invention will be better understood thanks to the description which follows given by way of nonlimiting example with regard to the appended drawings in which
Figure 1 shows a schematic perspective view of a device according to the invention.

 FIG. 2 represents a schematic view in longitudinal section of a device according to the invention.

 FIG. 3 represents a schematic view in the direction of insertion of a device according to the invention.

 Figure 4 shows a partial sectional view along line IV-IV of Figure 3 of a device according to the invention.

 With reference to FIGS. 1 to 4, the identical references designate in each figure elements which are identical or functionally equivalent to the corresponding elements in the other figures.

 A heating resistor R shown diagrammatically in broken lines comprises a cold supply end constituted by a cylindrical end piece 1.

 The relative movement of the electrical connection corresponds to a translation indicated by the arrow of reference 2 until the position of complete insertion of the resistor inside the device according to the invention.

 The device according to the invention comprises for example a crimping block 3 on a supply conductor not shown and a connection socket 4 on the cylindrical end piece 1.

 The crimping block 3 comprises a first clamp 5 for the metallic central conductor and a second clamp 6 for the peripheral insulation of the metallic central conductor. According to the invention, a recess 7 is provided which defines a sinking stop for the peripheral insulator and prevents excessive penetration of the metallic central conductor so as to prevent any undesired direct electrical contact between the metallic central conductor and the end. cold 1: it is thus ensured that the electrical supply current passes entirely through the device according to the invention.

 The connection socket 4 comprises a series of strips 8a to 8e arranged alternately on either side of the cylindrical end piece 1 which they enclose elastically, as well as two raised edges 9, io extending longitudinally in the direction of plugging in 2.

 Thanks to the arrangement according to the invention, the plugging of a cylindrical end piece with a device according to the invention is carried out gradually by spreading only one pair of elastic strips at a time, while the rigidity of the socket connection is preserved by the raised edges 9 and 10 which constitute both mechanical stiffeners and thermal radiators homogenizing the temperature of the device according to the invention, so as to avoid any permanent deformation during the thermal cycling to which the device is subjected the invention.

 Advantageously, the strips 8a to 8e have the general configuration illustrated in FIG. 3: each strip 8a to 8e has a general V shape, each wing of which has two curved parts defining a line or a point of tangential contact with the cylindrical end piece 1 Each strip 8a to 8e thus comprises two curved parts 11a, 12a to island, 12e in tangential contact with the cylindrical end piece 1 according to a generatrix of the cylinder 1.

 Due to the fact that the contact is made only along a line or a point, the plugging of the device according to the invention on the cylindrical end piece 1 is carried out with a low longitudinal friction, although the transverse support of the parts curved 11 and 12 on the cylindrical end piece produced by the elastic V-shaped conformation of each strip takes place with a high contact pressure ensuring good electrical transmission at these support points.

 Preferably, according to a particular variant of the invention shown in FIG. 4, each curved part 11a to island, 12a to 12e, comprises a chamfer 13 or an engagement slope for the cylindrical end piece 1, a slightly inclined part 14 with respect to the insertion direction 2 facilitating the insertion, lifting and deformation of the corresponding strip 8 and an anchoring edge 15 which prevents the withdrawal of the cylindrical end piece 1 in the opposite direction to the insertion direction symbolized by the arrow 2.

 This particular conformation causes, during the thermal cycling to which the resistance is subjected, an oblique twist of the curved parts 11 and 12, which tends to anchor them deep in the cylindrical end piece, by achieving reliable mechanical support and perfect electrical contact. without hot spots, due to the fact that the electric current flows in a distributed manner at ten contact points corresponding to the curved parts 11a to 11a and 12a to 12e.

 The electrical connection devices according to the invention are entirely satisfactory; the invention also covers any modification of shape, in particular the case of a connection of wires perpendicular to the insertion axis, or any other variant embodiment in a resilient material ensuring the preservation of the mechanical, elastic and electrical properties during continuous thermal cycling produced by a heating resistor of known type.

Claims (10)

 1. - Electrical connection device, in particular for a cylindrical end piece, capable of supplying an electrical heating resistor comprising at least one cold end which is substantially cylindrical, characterized in that the device comprises a connection socket (4) comprising a series of strips ( 8a-8e) arranged alternately on either side of the endpiece to be clamped.  2. - Device according to claim 1, characterized in that the device comprises a crimping block (3) with a first clamp (5) for a central conductor, a second clamp (6) for the peripheral insulator and a recess ( 7) provided to define a sinking stop for the peripheral insulation.  3. - Device according to one of claims 1 or 2, characterized in that the connection socket (4) has two raised edges (9, 10) extending longitudinally in the direction of insertion (2).  4. - Device according to claim 3, characterized in that the raised edges (9, 10) constitute mechanical stiffeners and thermal radiators, so as to homogenize the temperature and to avoid any permanent deformation resulting from thermal cycling.  5. - Device according to one of the preceding claims, characterized in that each strip (8a-8e) has a general V shape with two curved parts (lla-lle, 12a-12e) in tangential contact with the nozzle ( 1).  6. - Device according to claim 5, characterized in that the tangential contact takes place according to a generator in the case of a cylindrical tip (1).  7. - Device according to claim 5, characterized in that the tangential contact takes place in a point area.  8. - Device according to any one of claims 5 to 7, characterized in that the curved parts (lla-lle, 12a-12e) comprise a chamfer (13) or an engagement slope of the end piece (1) .  9. - Device according to any one of claims 5 to 8, characterized in that the curved parts (lla-ller 12a-12e) have a part (14) slightly inclined relative to the direction of insertion (12).  10. - Device according to any one of claims 5 to 9, characterized in that the curved parts (lla-lle, 12a-12e) comprise at least one anchoring edge (15) preventing the withdrawal of the end piece ( 1).