Microwave oven

Abstract

 A microwave oven having an electric connector (100) for conveying current to a fan motor (44) and a tray drive motor. The electric connector including a plurality of male terminals (111,112 and 113) coupled on the fan motor; a plurality of female terminals (141, 142 and 143) for coupling on the male terminal; a plurality of terminal housings (131 and 132) for receiving the female terminal; and a device for guiding an inserting position of at least one of the female terminals into at least one of the male terminals. The devices includes a position guide projection (135) extending from a side of one of the terminal housing, the position guide projection being formed extending over one side end of the fan motor.

Description

[0001] The present invention relates to an electrical coupling comprising a first structure having a plurality of first terminals and a second structure having a plurality of second terminals for connecting with respective ones of the first terminals.

[0002] A conventional microwave oven is illustrated in Figure 1 and comprises a cabinet 10, a cooking chamber 20 and an electrical components chamber 30. Several components, necessary for the generation and transmission of microwaves, are mounted within the electrical component chamber 30 including a magnetron 31, a high-potential transformer 32 and a high-potential capacitor 33. A cooling fan 40 is used to dissipate the heat generated by the electrical components and to expel moisture and odour from the cooking chamber 20. A circuit board 45 is mounted to the rear wall above the cooling fan 40, and comprises a choke coil, for removing electrical noise, and a fuse for preventing damage to electric components. The incoming electric power is rectified by the circuit board 45 before being supplied to each electrical component.

[0003] A known cooling fan 40 is illustrated in Figure 2 and comprises a case 41 and a plurality of rotating blades 43 which are driven by a fan motor 44. The rotating blades 43 and the fan motor 44 are supported by a lattice-shaped supporting member 42, mounted within the case 41. A first, second and third male terminal 71, 72 and 73 are mounted on the upper end of the fan motor 44 which transmit electric power from the circuit board 45 (see Figure 1) to the fan motor 44 and beyond to a tray drive motor. The tray drive motor rotates a tray 21 mounted to the bottom of the cooking chamber 20 (Figure 1). The first second and third male terminals 71, 72 and 73 are coupled to the first, second and third female terminals 74, 75 and 76 respectively. The first female terminal 74 is connected to the first and second wires 77a and 78a, and the second and third female terminals 75 and 76 are connected to the third and fourth wires 78b and 77b respectively. The first and fourth wires 77a and 77b lead from the circuit board 45 and the second and third wires 78a and 78b lead from the tray drive motor.

[0004] The first and second male terminals 71 and 72 are connected to the second and third wires 78a and 78b via the first and second female terminals 74 and 75 and transmit electric power from the circuit board 45 to the tray drive motor. Meanwhile the first and third male terminals 71 and 73 are connected to the first and fourth wires 77a and 77b via the first and third female terminals 74 and 76 and transmit drive electric power to the fan motor 44. The first female terminal 74 is coupled to the ends of the first and second wires 77a and 78a by a single-type terminal housing 81, and the second and third female terminals 75 and 76 are coupled to ends of the third and fourth wires 78b and 77b by a dual-type terminal housing 82.

[0005] Since the first, second and third female terminals 74, 75 and 76 are separated by the single and dual-type terminal housings 81 and 82, the first male terminal 71 is prevented from being inserted into the dual-type terminal housing 82. This is further ensured by making the distance between the first and second male terminals 71 and 72 different from the distance between the second and third male terminals 72 and 73.

[0006] However, this electrical connecting structure has a drawback in that the dual-type terminal housing 82 may be reversed and coupled wrongly, such that the second and third female terminals 75 and 76 are connected to the third and second male terminals 73 and 72, respectively. Wrong assembly of the connecting structure causes the tray motor to be damaged by high voltage.

[0007] It is an aim of the present invention to ameliorate the aforementioned problem.

[0008] An electrical coupling according to the present invention is characterised in that the second structure is provided with a projection, and the first terminals are arranged such that the projection can extend beside the first structure, so as to allow mating of the first and second terminals, only when the first and second terminals are brought together in a predetermined orientation.

[0009] Preferably, the first terminals are male and the second terminals are female.

[0010] An electrical coupling according to the present invention may be employed in a microwave oven which includes a cooling fan and a cooling fan driving motor. The electrical coupling is suitable for supplying electric current to the cooling fan driving motor, and preferably the first structure comprises a planar element mounted to the motor and the first terminals project from a face of the planar element.

[0011] An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:

Figure 1 is a partial sectional view illustrating an electric component chamber of a conventional microwave oven;

Figure 2 is a rear view illustrating a conventional electrical connecting structure;

Figure 3 is a rear view illustrating an electrical connecting structure of a cooling fan according to a preferred embodiment of the present invention; and

Figure 4 is a view illustrating a coupling state of the electrical connecting structure according to a preferred embodiment of the present invention.

[0012] A cooling fan 40 may comprise a case 41, a support structure 42, a plurality of rotating blades 43 mounted to a front side of the support structure 42 which are driven by a fan motor 44 mounted to the rear side of the support structure 42. A coil board 120 for supporting a motor coil 121 is mounted on an upper end of the fan motor 44.

[0013] An electrical connecting structure 100 comprises a plurality of male terminals 111, 112 and 113 which extend outward from the coil board 120 and a plurality of female terminals 141, 142 and 143 respectively corresponding to the male terminals 111, 112 and 113. A first terminal housing 131 receives the first female terminal 141, while a second terminal housing 132 receives both the second and third female terminals 142 and 143. The first terminal housing 131 is of a single type and is inserted onto the first male terminal placed to the left side of the coil board 120. The second terminal housing 132 is of a dual-type and is inserted onto the second and third male terminals 112 and 113 found on the coil board 120.

[0014] To prevent the plurality of female terminals 141, 142 and 143 being incorrectly inserted onto the plurality of male terminals 111, 112 and 113, due to the first and second terminal housings 131 and 132 being switched, the distance between the first and second male terminals 111 and 112 is designed to be different from the distance between the second and third male terminals 112 and 113.

[0015] Now, the first female terminal 141 within the first terminal housing 131 is connected to the first and second wires 151a and 152a, while the second and third female terminals 142 and 143 within the second terminal housing 132 are connected to the third and fourth wires 152b and 151b respectively. Consequently, a relatively low voltage appears across the first and second male terminals 111 and 112 which is then transmitted, through the second and third wires 152a and 152b, to the tray drive motor in order to rotate the tray 21. Similarly, a relatively low voltage appears across the first and third male terminals 111 and 113 which is then transmitted, through the first and third wires 151a and 151b, to the fan motor 44.

[0016] Using a position guide projection 135 will also prevent the second terminal housing 132 from being inversely inserted. The projection 135 includes a vertical portion V extending a predetermined length from a side of the second terminal housing 132 and a horizontal portion H extending from a front end of the vertical portion V toward the coil board 120.

[0017] Figure 4 illustrates the successful connection of the electrical connector 100 to the coil board 120 where the horizontal portion H is formed extending over a right edge of the coil board 120 so that the horizontal portion H does not contact the coil board 120.

[0018] Attempts to couple the second terminal housing 132 in an inverted state will fail, since the horizontal portion H of the projection 135 meets the coil board 120 before the terminal housing 132 is inserted. The second terminal housing 132 is thus prevented from be inserted in a state where it is inverted.

[0019] It will be appreciated that many modifications can be made to the embodiments described above.

Claims

1. An electrical coupling comprising a first structure (120) having a plurality of first terminals (112, 113) and a second structure (132) having a plurality of second terminals (142, 143) for connecting with respective ones of the first terminals (112, 113), characterised in that the second structure (132) is provided with a projection (135), and the first terminals (112, 113) are arranged such that the projection (135) can extend beside the first structure (120), so as to allow mating of the first and second terminals (112, 113, 142, 143), only when the first and second terminals (112, 113, 142, 143) are brought together in a predetermined orientation.

2. An electrical coupling according to claim 1, wherein the first terminals (112, 113) are male and the second terminals (142, 143) are female.

3. A microwave oven including a cooling fan (43), a cooling fan driving motor (44) and an electrical coupling according to claim 2 for supplying electric current to the cooling fan driving motor (44), wherein the first structure (120) comprises a planar element (120) mounted to the motor and the first terminals (112, 113) project from a face of the planar element (120).

4. A microwave oven having an electric connector for conveying current to a fan motor and a tray drive motor, said electric connector comprising:

a plurality of male terminals coupled on the fan motor;

a plurality of female terminals for coupling on the male terminal;

a plurality of terminal housings for receiving the female terminal; and

means for guiding an inserting position of at least one of said female terminals into at least one of said male terminals.

5. A microwave oven of claim 4, wherein said means comprises a position guide projection extending from a side of one of the terminal housing, said position guide projection being formed extending over one side end of the fan motor.

6. A microwave oven of claim 5, wherein said terminal housing where the position guide projection is formed is a dual-type housing for receiving more than two female terminals.

Drawing