GB2308795A

GB2308795A - Microwave oven turntable driving apparatus

Info

Publication number: GB2308795A
Application number: GB9626458A
Authority: GB
Inventors: Hyoung-Joo Kang
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 1995-12-28
Filing date: 1996-12-20
Publication date: 1997-07-02
Anticipated expiration: 2016-12-20
Also published as: KR0176798B1; BR9606169A; CN1158962A; GB9626458D0; KR970047176A; GB2308795B

Description

MICROWAVE OVEN TURNTABLE DRIVING APPARATUS The present invention relates to a microwave oven, and more particularly to a microwave oven turntable driving apparatus capable of moving the turntable up and down as well as rotating same.

As shown in Figure 1 showing a structural view of a conventional turntable driving apparatus of a microwave oven, on a lower surface of a bracket 1 there is provided a motor 2 which is connected by a rotation shaft 3 to transmit rotation force generated by the motor 2 to a turntable base 4 connected to an upper end of the rotation shaft 3, and a turntable 5 is placed on the turntable base 4.

The operation and disadvantages of the thusly provided conventional turntable driving apparatus of a microwave oven will now be described.

First, when electrical current activates the motor 2, the motor shaft 3 is rotated in accordance with rotation force generated by the motor 2 so that the turntable base 4 provided on the upper end of the shaft 3 is rotated accordingly, thus to rotate the turntable 5 placed on the turntable base 4.

At this time, the turntable 5 receiving food thereon is rotated at the same rpm as the motor shaft 3, and high frequency micro wave energy generated from a magnetron (not shown) is applied to the food to warm or heat the food.

However, a lower portion of the food may not be evenly warmed or heated, compared to an upper portion thereof, mainly due to the horizontally rotating movement of the turntable 5.

Therefore, it is an aim of certain embodiments of the present invention to provide a microwave oven turntable drivi apparatus for moving the turntable up and down as well as rotating the turntable.

To achieve the above-described aims, the microwave oven turntable driving apparatus includes: a driving member provided on an upper portion of a motor, an engaging member provided adjacent to one side of the driving member for thereby being engaged to the driving member, a vertical movement guide provided on a lower surface of the engaging member and moving up and down the engaging member in a vertical rotation mode thereof, a shaft for transmitting engaged force of the engaging member while moving up and down along the vertical movement guide, and a turntable base mounted on a top end of the shaft.

Preferred embodiments of the present invention will now be described hereinbelow by way of example only with reference to the accompanying drawings in which: Figure 1 is a structural view of a conventional turntable driving apparatus of a microwave oven; Figure 2A is a cross-sectional view showing a turntable raised to a certain level, in a turntable driving apparatus of a microwave oven embodying the present invention; Figure 2B is a cross-sectional view showing the turntable lowered back to an initial level, in the turntable driving apparatus of a microwave oven embodying the present invention; Figure 3A is a plan view showing an inner guide of the turntable driving apparatus of a microwave oven embodying the present invention; Figure 3B is a partial cross-sectional view taken along line 0-III in Fig. 3A;; Figure 3C is a partial cross-sectional view taken along line 0-111 in Fig. 3A; Figure 4A is a developed view of SEC. A in Fig. 3A; Figure 4B is a developed view of SEC. B in Fig. 3A; Figure 5 is a developed perspective view provided by separating SEC. A from SEC. B in Fig. 3A; and Figures 6A and 6B are views showing the vertical operation of the turntable driving apparatus of a microwave oven embodying the present invention; with reference to Figs. 2A and 2B, on a lower surface of a lower bracket 10 there is mounted a motor 11 operating at a certain rpm. On a motor shaft 12 extending from the motor 11 there is provided a driving gear 20 operating in accordance with driving of the motor 11.

The driving gear 20 includes a first gear toothing 22 formed in the outer periphery of a disc-shaped outer body 21 connected to the motor shaft 12 extending from the motor 11, and a pair of projections 23 extended from an upper surface of the outer body 21 thus to be parallel and symmetrical to the motor shaft 12 in a static mode thereof.

A microswitch 30 is provided on an inner side surface of the lower bracket 10 and adjacent to the outer body 21 and also aligned, in a static mode, with the pair of projections 23 thus to serve to enable the driving of the gear 20 by the motor to be halted by sensing the projections 23.

The first gear toothing 22 formed on the side of the driving gear 20 is engaged to a second gear toothing 42 formed on the side of an outer-guide gear 40 which includes: the second gear toothing 42 formed in the outer periphery of a cylinder shaped body 41; an inner guide recess 43 formed in body 41 along a certain radius; and a cone shaped first sliding projection 44 having a rounded apex and extended from the outer periphery of the guide recess 43.

Here, the circumference of the body 41 of the outer-guide gear 40 is identical to that of the body of the driving gear 20 for thereby resulting in a rotation proportional to the rotation frequency of the driving gear 20.

On a lower portion of the outer-guide gear 40 and at a certain portion of the lower bracket 10 there is provided a ring shaped inner guide 50 for moving the outer-guide gear 40 up and down when rotating. In the center of the outer-guide gear 40 there is inserted an end portion of a shaft 60 so that a rotation force of the outer-guide gear 40 can be delivered to the shaft 60 while moving up and down along the inner guide 50.

A lower end of the shaft 60 is inserted in a disc shaped support plate 70 and a cone shaped second sliding projection 71 is formed along the outer periphery of the support plate thus to be rotated while supporting an inner lower portion of the inner guide 50. On an upper end of the shaft 60 there is mounted a turntable base 80 to be engaged to the outer-guide gear 40 and to have a moving path identical to that of the outer-guide gear 40, and on an upper surface of the turntable base 80 there is placed a turntable 81.

Around the middle of the shaft 60 there is provided a bearing bracket 80 fixed to an upper bracket 90, and inside the bearing bracket 82 toward the shaft 60 there is provided a bearing 83 to thereby support the shaft 60.

As shown in Fig. 5, a first orbit 51 approximating to a sine curve is formed in the upper side of the inner guide 50 so that the first sliding projection 44 of the outer-guide gear 40 can contact and slide therealong to an outer portion of the upper surface of the inner guide 50, and a second orbit 52 shaped after a sine curve is formed in the lower side of the inner guide so that the second sliding projection 71 of the support plate 70 can contact and slide therealong to the inner portion of the lower surface of the inner guide 50.

The operation and effect of the thusly provided turntable driving apparatus for a microwave oven in accordance with the present invention will now be described.

First, when electrical current is applied to cause rotation of the motor 11, the driving gear 20 provided on the motor shaft 12 of the motor 11 is rotated, and the outer-guide gear 40 and the driving gear 20 are engagedly rotated, with the shaft 60 inserted in the outer-guide gear 40 rotatably supported by the bearing 83 mounted in the bearing bracket 82.

At this time, as shown in Figs. 6A and 6B, the first sliding projection 44 and the second sliding projection 71 are moved along the corresponding paths of the orbits 51,52 of the inner guide 50, wherein the first sliding projection 44 of the first orbit 51 begins moving along the periphery of the orbit 51 at 0 , and at the same time the second sliding projection 71 of the support plate 70 begins moving along the periphery of the orbit 52 at 0", whereby the outer-guide 40 is caused to be moved up and down as well as to horizontally rotate.

The turntable base 80 mounted on the upper end of the shaft 60 is horizontally rotated with the rotation of the outer-guide gear 40 and at the same time moves up and down, and accordingly the turntable 80 moves along the same path of the turntable base 80.

Consequently, the turntable 81 rotates horizontally and at the same time moves up and down, whereby food placed on the turntable 81 can be evenly warmed or heated without regard to the lower or upper portion thereof.

When the food has been heated to a desired extent, the microswitch 30 detects a position wherein the projections 23 of the driving gear 20 are aligned therewith thus to halt the driving of the driving gear 20. Here, the first sliding projection 44 is located at 0 or 1800 of the first orbit 51 of the inner guide 50 as shown in Fig. 6A, and the second sliding projection 71 of the support plate 70 is located at 0 or 1800 of the second orbit 52 of the inner guide 50 as shown in Fig. 6B for thereby fluctuating the turntable 81.

As described above, the microwave oven turntable driving apparatus according to the present invention enables the turntable to make a vertical movement as well as a horizontal movement simultaneously thus to evenly warm or heat food on the turntable, thereby obtaining an enhanced function thereof.

Claims

CLAIMS:

1. A turntable driving apparatus for a microwave oven, comprising: a driving means provided on an upper portion of a motor for transmitting driving force of the motor; an engaging means provided adjacent to one side of the driving means for thereby being engaged to the driving means; a vertical movement guide provided on a lower surface of the engaging means and moving up and down the engaging means in a vertical rotation mode thereof; a shaft, a lower portion thereof being inserted in the engaging means thus to transmit engaged force from the engaging means while moving up and down along the vertical movement guide; and a turntable base mounted on a top end of the shaft and moving along a movement path of the engaging means.

2. The apparatus of Claim 1, wherein the driving means comprises a driving gear having a first gear toothing formed in an outer periphery of a disc-shaped outer body thereof connected to a shaft of the motor, and including a pair of projections extended from an upper surface of the outer body horizontally symmetrical to the shaft in a static mode thereof.

3. The apparatus of Claim 1 or 2, wherein the engaging means comprises a guide gear including a second gear toothing formed in an outer periphery of a cylinder shaped body thereof and engaged to a first gear toothing of a driving gear, a guide recess being formed along an inner radius of the body, and a cone shaped first sliding projection having a round apex and extended from an outer periphery of the guide recess.

4. The apparatus of any of Claims 1, 2 or 3, wherein a lower end of the shaft is inserted in a disc shaped support plate, and a cone shaped second sliding projection is formed along an outer periphery of the support plate thus to be rotated while supporting an inner lower portion of the vertical movement guide.

5. The apparatus of any of the preceding claims, wherein the vertical movement guide comprises a ring shaped inner guide including a sine-curve shaped first orbit formed in an upper side thereof so that a first sliding projection of a guide gear can contact and slide therealong to an outer portion of the upper surface of the inner guide, and a sine-curve shaped second orbit formed in a lower surface thereof so that a second sliding projection of a support plate can contact and slide therealong to an inner portion of the lower surface of the inner guide.

6. The apparatus of Claim 2 or any of Claims 3 to 5 when dependent on Claim 2, wherein a microswitch is provided on an inner side surface of a lower bracket and adjacent to the outer body thus to enable the driving means to halt by sensing the projections of the outer body.

7. The apparatus of Claim 3 or any of Claims 4 to 6 when dependent on Claim 3, wherein a circumference of the body of the guide gear is identical to that of the body of the driving gear.

8. A turntable driving apparatus for a microwave oven substantially as hereinbefore described with reference to Figures 2A, 2B, 3A, 3B, 3C, 4A, 4B, 5, 6A and 6B of the accompanying drawings.