Turntable for Use in a Microwave Oven

1. Field of the Invention

The present invention relates to an up-and-down turntable for use in a microwave oven, and more particularly, a turntable which enables to be moved up and down during its rotation for uniformly heating the cooking object.

2. Description of the Prior Art

In a conventional art, a microwave oven as shown in FIG. 1 contains a turntable which, during its rotation, is moved up and down to heat the cooking object although the heat cannot heat the cooking object uniformly.

The conventional turntable 1' as shown in FIG. 1 is operatively disposed in an annular holder 11' of a bottom plate 10'. An annular cam member 6' disposed in a case 3' includes a gear 8' disposed thereon and an inclined cam face 6". The case 3' is provided with a motor 2' of which a shaft 2a is coaxially mounted with a super gear 9' which gears together with the gear 8' of the cam member 6' which is adapted to receive an axle 7' disposed therein.

According to the prior art (FIG. 1) the turntable is driven for rotation by the super gear 9' which is mounted coaxially with the shaft 2a' of the motor 2'. And the rotation of the super gear 9' is caused to rotate the cam member 6' by gearing together with the gear 8' and also to rotate the turntable which is operatively connected to the cam member 6'.

The inclined cam face 6" disposed on the bottom surface of the cam member 6' operatively contacts with a roller 12', therefore, the rotating turntable 1' is moved up and down the distance between the dotted line position and the solid line position as shown in FIG. 1.

However, the conventional turntable is required many components since the mechanism of the up-and-down movement of the turntable in rotation becomes complicated. Furthermore, since the cam face 6" has a fixed, inclined configuration, the cam face limits the up-and-down movement of the turntable. Therefore, the microwave applies only in a limited portion of the cooking object.

Accordingly, the present invention relates to a turntable which includes a tray supporting an object to be heated and a motor which is directly coupled to each other and a roller revolving on the surface of a case floor, attached to the tray for rotating, and rocking sideways the tray while the turntable moves up and down.

FIG. 1 is a sectional view of a turntable of a conventional art;

FIG. 2 is a sectional view of a turntable of the present invention;

FIG. 3 is a cross-sectional view of a roller of the present showing a clearance during its vertical operation;

FIG. 4 is a sectional and enlarged view of the roller the present invention showing a width during its rocking sideways operation; and

FIG. 5 a sectional view illustrating another embodiment of the present invention.

Referring now in detail to the drawings for the purpose of illustrating preferred embodiment of the present invention, as shown in, FIG. 2 the turntable of the present includes a rotating tray 1 provided with an annular holder 11 disposed in a bottom plate 10 which is adapted to be operatively mounted to a stem portion 1a extended from the tray 1. The stem portion 1a includes a cavity 4 disposed along its center thereof for being adapted to receive a shaft 7 extended from the motor 2. A case 3 fixed to the bottom plate 10 has a motor 2 attached thereto, which includes a shaft 2a thereof so as to rotate and move up and down the tray 1 during the rotation of the motor 2. The tray 1 is provided with a recess 5 disposed in one side thereof large enough to receive a disc roller 6 having a pin hole 6a for being slidably received a pin 7 therewithin through an aperture 5a disposed in a rotatable axle 1a.

The pin hole 6a of the roller 6 is formed a larger diameter than a diameter of the pin 7 and is located at an eccentric position disposed on the disc roller 6 as shown in FIG. 3. The rotation of the tray 1 driven by the motor 2 operates within a differential height .alpha. between an upper and lower dead centers A and B during the up-and-down movement of the disc roller 6.

According to the enlarged section view of the roller 6 as shown in FIG. 4, the roller 6 has a Disc-shaped configuration with its rounded edges and is provided with the pin hole 6a disposed at an eccentric position for being adapted to slidably receive the pin 7. Also the pin 7 passes away in the aperture 5a disposed in the stem portion 1a so that the roller 6 rocks sideways in an angle .theta. in the recess 5 disposed in the tray 1 and maintains, in rocking sideways, the horizontal balance of the tray 1 in the same angle .theta..

In the present invention, while the tray 1 is horizontally rotated by the rotation of the motor causing the roller 6 to make it roll along the surface of a case floor 3a.

Therefore, the rotation of the roller 6 from the lower dead center A to the upper dead center B, in turn, from the upper dead center B to the lower dead center A gives a differential height .alpha. so that the continual rotation of the roller 6 is a reciprocating motion in the range of the distance .alpha. along with the same up-and-down movement of the rotating tray 1.

Besides, the tray 1 in the up-and-down movement rocks sideways in the angle .theta. since the roller 6 rocks sideways in the angle .theta..

According to another embodiment of the present invention as shown in FIG. 5, the tray 1 is provide with a gear 8a' at its lower portion, that is, at the stem portion 1a for gearing together with a housing gear 8 disposed in an inner wall of a housing 9. The structure of the device as shown in FIG. 5 is so constructed that the tray is rocked during its rotation horizontally and simultaneously vertically. The drive power from the motor 2 is spreadably transmitted to the tray 1 through the gear 8 to the housing gear 8a. The rotation of the tray 1 and the roller 6 with the eccentrically positioned pin 7 is to cause the up-and-down movement of the tray along with the rocking movement of the roller 6 for bringing forth a better application of the microwave to the object on the tray.

As shown above, the construction of the present invention, wherein the motor is directly coupled to the tray which contains the roller being arranged to roll on the surface of case floor at the eccentric position so as to not only simplify but also readily facilitate the assembling process.

In addition, the clearance of the pin hole gives a side rocking of the roller in the angle .theta. which, in turn, rocks the tray with cooking objects in horizontally rotation and in vertically up-and-down movement for achieving the uniform heat to the object to be cooked.