GB2303771A

GB2303771A - Microwave oven with moveable heater

Info

Publication number: GB2303771A
Application number: GB9613879A
Authority: GB
Inventors: Sang-Young Bae
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 1995-07-24
Filing date: 1996-07-02
Publication date: 1997-02-26
Anticipated expiration: 2016-07-02
Also published as: BR9603136A; CN1155054A; KR970006489U; KR0136606Y1; GB9613879D0; CN1088173C; GB2303771A8; DE19629290A1; GB2303771B

Description

2303771 MICROWAVE OVEN WITH A MOVABLE HEATE

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates in general to a microwave oven provided with a movable heater inside a cavity of the oven housing and, more particularly, to a structural improvement in a heater rotating unit of such a microwave oven for manually rotating the movable heater outside the oven housing.

Description of the Prior Art is As well known to those skilled in the art, composite- heating type microwave ovens with both a magnetron for primary heating and an additional heater for secondary heating have been proposed and used. The heater in the above ovens is typically provided in the cavity of the oven housing In the above composite-heating type microwave ovens, the heater is rotatably mounted to the rear portion of a cavity and is rotated to adjust the position thereof so as to uniformly heat food in the cavity. The construction of a typical composite-heating type microwave oven is shown in Fig.l. As shown in Fig. 1, a turntable 2 is rotatably mounted to the bottom of the cavity 1. A movable heater is 1 pivotally mounted to the rear portion of the cavity top wall by a pin 4.

In order to uniformly heat food in the cavity 1 of the above microwave oven, the position of the heater 3 must be often adjusted manually with a jig 11J11 with the cavity door open during a cooking process of the oven.

When the movable heater 3 fails to be held in an adjusted position inside the cavity 1, the heater 3 may cause microwave concentration onto only a part of the fpod or may prevent the food from being uniformly heated. In order to overcome the above problems, the typical microwave oven with such a heater 3 may be provided with a structure for holding the heater 3 in an adjusted position as shown in Figs. 2 and 3.

Is The above heater holding structure comprises a guide 6 which is provided on a given position in each side of the rear wall 5 of the cavity 1. Each guide 6 has upper and lower elastic hooks 6a and 6b spaced apart from each other. A stopper 8, which is integrated with the heater 3 into a single body, is placed relative to the above guide 6 in a way such that the stopper 8 can be brought into engagement with either hook 6a, 6b in accordance with a rotating motion of the heater 3. Due to the above heater holding structure, the stopper 8 engages with either hook 6a, 6b when the heater 3 is manually manipulated by the jig 11J91 in order to place the heater 3 in the upper or rear position inside the cavity 1.

2 The heater 3 can be thus held in the adjusted position.

In the drawings, the reference numeral 9 denotes an input terminal of the heater 3.

However, whenever the position of the heater 3 is adjusted, the above heater 3 must be manually manipulated by the jig "J" with the cavity door open during the cooking process of the oven. It is thus difficult to adjust the heater position inside the cavity I and is inconvenient to users. In addition, the jig "ill for operating the heater 3 must be always placed near the oven and loss of the jig may force the user to purchase new one.

Another disadvantage of the above oven resides in that the user may happen to be burnt while manually handling the high temperature heater 3 with the jig "J".

U.S. Patent No. 4,629,850 discloses a microwave oven with an automatically-rotated heater which can overcome the problems caused by the above manually-rotated heater.

However, the microwave oven disclosed in the above U.S. patent has a problem in that it must be equipped with a heater operating and controlling unit having a complex construction. The above apparatus, which comprises a motor for rotating heater, a detection unit for detecting heater position, motor control circuit and the like, thus increasing the cost of the oven. Another disadvantage of the above microwave oven resides in that the position of the heater automatically varies in accordance with the types of food in Is 3 the cavity, thus causing microwave concentration onto only a part of the food.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a microwave oven with a movable heater in which the above problems can be overcome and whose movable heater can be manually rotated outside the housing of the oven, thus being convenient to users.

In order to accomplish the above object, a microwave oven in accordance with the present invention comprises a movable heater installed inside the cavity of the oven, and a heater rotating unit including a heater handling means mounted outside the housing of the oven, and a power transmission means for transmitting the rotating force of the heater handling means to the heater and thereby causing the heater to be rotated in accordance with a manipulation of the heater handling means.

In this invention, the heater handling means may comprise a rotating dial or lever which is rotatably mounted to the top wall of the oven housing and generates the rotating force to be transmitted to the heater through the power transmission means.

The above power transmission means may comprise a first gear fixed to the rotating body of the movable heater, and a 4 second gear fixed to an integrated central shaft of the rotating dial or lever and gearing into the first gear.

The above rotating dial may comprise a handle knob provided outside the top wall of the oven housing, and a holder rotatably fitted into the knob by a fitting structure and including a plurality of hooks extending downward from the holder and caught by the top wall of the oven housing to retain the knob In the rotatable position with respect to the top wall. Meanwhile, the rotating lever is provided outside the top wall of the oven housing and can be rotated within a given rotating angle.

In accordance with another embodiment, the heater handling means may comprise a rotating lever which is rotatably mounted to either rear or side wall of the oven is housing and generates.the rotating force to be transmitted to the heater through the power transmission means.

When the heater handling means comprises the rotating lever mounted to the rear wall of the housing, the power transmission means preferably comprises a first gear fixed to the body of the movable heater, and a second gear fixed to an Integrated central shaft of the lever and gearing into the first gear.

When the heater handling means comprises the rotating lever mounted to a side wall of the housing, the power transmission means preferably comprises the rotating shaft of the rotating lever which is directly linearly coupled to the rotating shaft of the movable heater. In this case, the rotating shaft of the heater is directly coupled to the rotating lever.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be moreclearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a side view of a typical microwave oven, showing the rotating motion of the movable heater inside the cavity; Figs. 2 and 3 show the construction of a typical heater is holding structure adapted for holding the movable heater in an adjusted position, wherein Fig. 2 is a side sectional view of the heater holding structure; Fig. 3 is a left-hand side view of the heater holding structure of Fig. 2; Fig. 4 is a schematic front view of a microwave oven provided with a heater rotating unit for manually rotating the movable heater outside the oven housing in accordance with a primary embodiment of the present invention; Fig. 5A is an enlarged view of the portion "All of Fig.

6 Fig. 5B is a right-hand side view of the portion "All of Fig. 4; Fig. 6 is a sectional view of the portion "B" of Fig. 4; Fig. 7 is a plan view of the portion "B" of Fig.4; Fig. 8 is a side sectional view showing the onstruction of a microwave oven provided with a heater rotating unit in accordance with another embodiment of the present invention; and Fig. 9 is a right-hand side view of the heater rotating unit of Fig. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figs. 4 to 7 show the construction of a microwave oven provided with a heater rotating unit for manually rotating the movable heater outside the oven housing in accordance with a primary embodiment of the present invention. in the following description, elements common to both the prior art and the present invention will carry the same reference numerals.

As shown in Figs. 4 to 7, the microwave oven of this invention comprises a movable heater 13 which is installed inside the cavity 12 of the oven. In the above oven, the heater rotating unit includes a heater handling means mounted outside the housing of the oven. The above unit also includes a power transmission means which transmits the 7 rotating force of the heater handling means to the heater 13 and thereby causes the heater 13 to be rotated in accordance with a handling direction of the heater handling means.

In the above embodiment, the heater handling means for generating the rotating force to be transmitted to the heater 13 through the power transmission means comprises a rotating dial 15, which is rotatably mounted exteriorly to the top wall 14 of the oven housing.

The above power transmission means includes a first gear 17 fixed to the rotating body 16 of the movable heater 13 as shown in Fig. 5A. The above power transmission also includes a second gear 19 which is f ixed to the distal end of an integrated central shaft IS of the rotating dial 15 and gears into the above first gear 17.

As shown in Fig. 6, the above rotating dial 15 includes a handle knob 20 which is provided outside the top wall 14 of the oven-housing. The above central shaft 18 with the second gear 19 is integrated with the bottom center of the above knob 20 into a single body and vertically penetrates down through the top wall 14 thereby extending inside the top wall 14. In the above knob 20, an annular bottom recess is defined on the bottom surface of the knob 20 around the shaft 18. The above dial 15 further includes an annular knob holder 22 which holds the knob 20 in the rotatable position with respect to the top wall 14. The above holder 22 is rotatably fitted into the bottom recess of the knob 20 by 8 is means of a fitting structure 21 comprising a prominence and depression. In the above fitting structure 21, the prominence is formed on the outer edge of the holder 22, while the depression is formed on the mating side wall of the bottom recess in the knob 20. A plurality of hooks 22a vertically extend downward from the holder 22 and are caught by the top wall 14 to retain the knob 20 in the rotatable position with respect to the wall 14.

The above holder 22 not only prevents the knob 20 from sudden separation from the top wall 14, it also allows a smooth rotation of the knob 20 thus preventing frictional contact between the knob 20 and the top wall 14 during the rotating motion of the knob 20.

Integrally mounted to the bottom side of the first gear 17 is a stopper 8. , In the present invention, it is preferred to use a zerol bevel _gear pair with Intersecting axes as the first and second gears 17 and 19 of the power transmission means.

The operation of the microwave oven according to the present invention will be described hereinbelow.

When the handle knob 20 of the rotating dial 15 is manually rotated in a desired direction, the central shaft 18 is rotated. The above shaft 18 thus in turn rotates the second gear 19 fixed to the distal end thereof. Since the f irst and second gears 17 and 19 gear into each other as described above, the first gear 17 is rotated by the rotating 9 f orce of the second gear 19. Due to the rotating motion of the first gear 17, the movable heater 13 inside the cavity 12 is rotated in the desired direction and thereby displaced into an adjusted position.

While the heater 13 is rotated by the rotating motion of the f irst gear 17 as described above, the stopper 8 of the first gear 17 is also rotated in the same direction and thereby is caught by either hook 6a or 6b of the guide 6 as described for the prior art microwave oven. therefore, the above heater 13 stably remains in the adjusted position.

In the present invention, the above knob 20 of the rotating dial 15 may be substituted with a rotating lever which is fixed to the central shaft 18. The construction of the heater handling means comprising the rotating lever Is instead of the knob 20 may be referred to the embodiment shown in Figs. 8 and 9. The above rotating lever has an advantage in that it simplifies the construction of the heater handling means and makes it easy to handle the heater handling means.

Figs. 8 and 9 show the construction of a heater rotating unit in accordance with another embodiment of the present invention. In this embodiment, the heater handling means comprises a rotating lever 24 that is rotatably mounted to the rear wall of the oven housing.

In the power transmission means of the above embodiment of Figs. 8 and 9, the first gear 17 is fixed to the rotating body 16 of the movable heater 13 as described for the primary embodiment of Figs. 4 to 7. Meanwhile, the second gear 19 gearing into the above first gear 17 is fixed to the distal end of a central shaft 25 of the above rotating lever 24.

In the operation of the above embodiment, the central shaft 25 of the lever 24 rotates the second gear 19 when the lever 24 is manually rotated in a desired direction. Thus, the first gear 17 gearing into the second gear 19 is rotated by the rotating force of the second gear 19 and thereby rotates the movable heater 13 inside the cavity 12 and adjusts the position of the heater 13.

While the heater 13 is rotated by the rotating motion of the first gear 17, the stopper 8 of the first gear 17 is also rotated in the same direction and thereby is caught by either Is hook 6a or 6b of the guide 6 as described for the primary embodiment. The above heater 13 thus stably remains in the adjusted position.

In accordance with a further embodiment of the present invention, the rotating shaft of the movable heater 13 may be directly coupled to the rotating shaft of a rotating lever mounted to a side wall of the oven housing. That is, the heater 13 may be directly coupled to the rotating lever without the power transmission gears 17 and 19 and thereby directly rotated by handling the lever outside the oven housing. In this case, the lever can be more easily handled since the lever is mounted to the side wall instead of the 11 is rear wall of the oven housing. Another advantage of the above unit resides in that it is free from the power transmission gears, thereby simplifying the construction and reducing the cost.

As described above, the present invention provides a microwave oven with a structural ly-improved heater rotating unit. In the above microwave oven, the movable heater provided inside the cavity is easily rotated to a desired position by manually handling a heater handling means provided outside of the oven housing. Since the movable heater inside the cavity is handled outside the oven housing in accordance with the present invention, the present invention eliminates the problems caused by the typical microwave oven with the movable heater which must be directly handled by a user with a jig with the cavity door open during the heating operation of the oven.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, hose skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

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Claims

WHAT IS CLAIMED IS:

1. A microwave oven comprising: a movable heater provided inside a cavity of an oven housing; and a heater rotating unit for allowing said heater to be manipulated outside the oven housing, said unit including:

a heater handling means mounted outside said oven housing; and a power transmission means for transmitting the rotating force of said heater handling means to the heater and thereby causing the heater to be rotated in accordance with a handling direction of the heater handling means.

2. The microwave oven according to claim 1, wherein said heater handling means comprises: a rotating dial exteriorly mounted to a top wall of said oven housing and generating the rotating force to be transmitted to the heater through said power transmission means.

3. The microwave oven according to claim 1, wherein said heater handling means comprises: a rotating lever exteriorly mounted to a top wall of said oven housing and generating the rotating force to be 13 transmitted to the heater through said power transmission means.

4. The microwave oven according to any one of claims 1 to 3, wherein said power transmission means comprises:

a f irst gear fixed to a rotating body of said movable heater; and a second gear fixed to. an integrated central shaft of said heater handling means and gearing into said first gear.

5. The microwave oven according to claim 2, wherein said rotating dial comprises:

a handle knob provided outside the top wall of the oven housing; and a knob holder adapted for holding said knob in a rotatable position with respect to the top wall of the oven housing, said holder being rotatably fitted into said knob by means of a fitting structure and having a plurality of hooks, said hooks vertically extending downward from the holder and being caught by the top wall to retain the knob in the rotatable position with respect to the top wall.

6. The microwave oven according to claim 1, wherein said heater handling means comprises: a rotating lever exteriorly mounted to a rear wall of said oven housing and generating the rotating force to be 14 transmitted to the heater through said power transmission means.

7. The microwave oven according to claim 6, wherein said power transmission means comprises: a first gear fixed to a rotating body of said movable heater; and a second gear fixed to an integrated central shaft of said rotating lever and gearing into said first gear.

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8. The microwave oven according to claim 4 or 7, wherein said first and second gears comprise a bevel gear pair.

9. A microwave oven comprising: a movable heater provided inside a cavity of an oven housing; and a rotating lever adapted for handling said heater outside the oven housing, said lever having a rotating shaft directly linearly coupled to a rotating shaft of said heater.

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10. A microwave oven constructed and arranged substantially as described in relation to Fig.4 or Fig.8 of the accompanying drawings.

11. A heater rotating unit constructed and arranged substantially as described in relation to Figs.4-7, or Figs.8 and 9, of the accompanying drawings.

12. A heater handling means constructed and arranged substantially as described in relation to Figs. 6 and 7, or Figs.8 and 9, of the accompanying drawings.

13. A power transmission means constructed and arranged substantially as described in relation to Figs.4,5A and 5B, or Fig.8, of the accompanying drawings.

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