Door opening and closing system in electric oven

A door opening and closing system for a electric oven is provided. The system includes: at least one latch provided at one side surface of a door; a door interlocking structure having a rotary lever, a switch and an elastic spring to sense opening and closing of the door, the rotary lever being pushed by the latch to rotate about one side, the switch sequentially contacting with the rotary lever, and the elastic spring allowing the rotary lever to be supported in one direction; and a door locking structure having a motor, a rotary unit and a latch guide unit, the motor rotating after it is sensed that the door is closed by the door interlocking structure, the rotary unit engaged with and rotated about a rotary shaft of the motor, and the latch guide unit being associated with the rotary unit to change a rotation motion of the rotary unit into a straight-line motion such that the door is latched to the latch to prevent an erroneous opening of the door.

TECHNICAL FIELD

The present invention relates to a door opening and closing system for an electric oven, and more particularly, to a door opening and closing system for a electric oven in which a door opening and closing operation can be accurately indicated, and when a door is locked, a cavity can be safely shielded.

Further, the present invention relates to a door opening and closing system for a oven in which when the oven is erroneously used, it stops its operation, thereby more safely using the oven.

BACKGROUND ART

Generally, a electric oven is an apparatus for heating and cooking food by an electric heater at a tray of within a cavity. The electric oven can perform functions of a grill and an oven by radiant heat of the electric heater or by a convectional hot blast caused by a convection fan. Additionally, in case where a magnetron is further provided, the magnetron irradiates microwave into the cavity to more promptly cook the food.

Generally, the electric oven has a door at a front thereof. The door performs an opening and closing operation up and down by a hinge provided at a lower side of the door. Additionally, a latch provided at an upper end of the door is inserted and latched in a latch insertion hole provided at a front surface of the electric oven. Accordingly, the door can be safely maintained in a closed state. Additionally, when the user opens the door, the latch is unlatched using a predetermined unit to allow the user to open the door. Further, a predetermined door switch is provided to sense the insertion of the latch into the latch insertion hole. In case where it is determined that the latch is inserted into the latch insertion hole, it is determined that the door is closed and the electric oven initiates its operation. In case where it is determined that the latch is not inserted into the latch insertion hole, the electric oven does not initiate its operation even though a start button is pressed.

Alternatively, the related-art electric oven has a drawback as follows.

First, there is a drawback in that when the user opens the door without recognizing that the internal of the cavity reaches a high temperature, he/she can get burned. In order to prevent this, U.S. Pat. No. 6,315,336 entitled “MOTORIZED SELF-CLEANING OVEN LATCH” has been disclosed. Since the U.S. patent has a drawback due to a complicated structure in that an actual embodiment is difficult and a manufacture cost is increased.

Second, in case where the user inserts a long stick into the latch insertion hole for fun, it can be erroneously sensed as if the door is closed. At this time, since the electric oven can be operated even without any manipulation, the user can get burned. Furthermore, there is also a drawback in that the indoor fire can be caused in case where the electric oven performs the above operations in an overheating state.

DISCLOSURE OF THE INVENTION

Accordingly, the present invention is directed to a door opening and closing system for a electric oven that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a door opening and closing system for a electric oven in which an accident can be prevented while the electric oven is used.

Another object of the present invention is to provide a door opening and closing system for a electric oven in which a reliable door opening and closing system is provided, thereby increasing a user's convenience much more.

A further another object of the present invention is to provide a door opening and closing system for a electric oven in which an endangerment of a user caused by a careless use is reduced or a danger of indoor fire caused by heat of the electric oven is reduced.

A still another object of the present invention is to provide a door opening and closing system for a electric oven in which it can be simplified in structure, thereby reducing a manufacture cost and enhancing a convenience in product application.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, there is provided a door opening and closing system for a electric oven, the system including: at least one latch provided at one side surface of a door; a door interlocking structure having a rotary lever, a switch and an elastic spring to sense opening and closing of the door, the rotary lever being pushed by the latch to rotate about one side, the switch sequentially contacting with the rotary lever, and the elastic spring allowing the rotary lever to be supported in one direction; and a door locking structure having a motor, a rotary unit and a latch guide unit, the motor rotating after it is sensed that the door is closed by the door interlocking structure, the rotary unit engaged with and rotated about a rotary shaft of the motor, and the latch guide unit being associated with the rotary unit to change a rotation motion of the rotary unit into a straight-line motion such that the door is latched to the latch to prevent an erroneous opening of the door.

According another aspect of the present invention, there is provided a door opening and closing system for a electric oven, the system including: a latch provided at one side surface of a door; a first door opening and closing structure having a motor, a rotary unit, and a latch guide unit, the motor rotating in both directions when the latch is inserted/released, the rotary unit being engaged to a rotary shaft of the motor to rotate at a predetermined angle, and the latch guide unit having one end inserted into the rotary unit at a predetermined position and the other end latched to the latch; and a second door opening and closing structure provided at a position adjacent to the latch to indicate an opening and closing state of the door.

According to a further another aspect of the present, invention, there is provided a door opening and closing system for a electric oven, the system including: a protrusion protruded from one side surface of a door; a second door opening and closing structure having a rotary lever, a switch, and an elastic member, the rotary lever rotating in contact with the protrusion when the door is closed, the switch sequentially contacting with the rotary lever to perform a plurality of switching operations when the rotary lever is rotated, the elastic member applying one-direction elastic force to the rotary lever to indicate a position of the rotary lever; and a first door opening and closing structure maintaining the door to be in a locking state after the door is closed by the second door opening and closing structure.

The inventive door opening and closing system has an effect in that since it can prevent a great disaster from being generated when the electric oven is erroneously operated, a safety is more increased in use.

In particular, since the inventive door opening and closing system can prevent the door from being opened due to a careless use when an internal of the cavity is at a high temperature, the safety is more increased in use.

Further, the inventive door opening and closing system has an advantage in that it prevents the door from being erroneously sensed as being closed due to the foreign substance, there is not a danger of indoor fire caused by high heat of the electric oven.

Furthermore, the inventive door opening and closing system has an advantage in that the door opening and closing system for the electric oven is simplified in structure to reduce a manufacture cost and more increase a product application in convenience.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1is a perspective view illustrating a electric oven according to the present invention.

Referring toFIG. 1, the inventive electric oven1includes a cavity3having a heater; a door30selectively opened and closed at one surface of the cavity3to put food in and out the cavity; a latch150provided at one side of within the door30; an insertion hole6provided at one side surface of a housing5to insert the latch150, thereby fixing the door30to the housing5.

An operation of a door opening and closing system of the electric oven according to the present invention is described in brief.

If a user seals the cavity3by the door30, the latch150is inserted into the insertion hole6. At this time, a first door opening and closing apparatus latches the latch150in the insertion hole6. Additionally, when objects such as a spoon are erroneously inserted into the insertion hole6, a second door opening and closing apparatus senses that the inserted object is not the door30and determines that the door is not in a closed state, thereby enhancing safety in use. The first door opening and closing apparatus is a door locking apparatus, and the second door opening and closing apparatus is an interlocking apparatus.

In detail, the interlocking apparatus is a structure for preventing, when the user inserts a stick into the insertion hole6for fun, a door switch in the insertion hole6from sensing as if the door is in the closed state. In case where it is sensed as if the stick inserted for fun is the door, thereby initiating an operation of the electric oven, there is a danger in safety such as indoor fire. Therefore, only when the latch150is exactly inserted, it should be determined that the door is in the closed state.

Alternatively, the inventive electric oven can also include a manipulation unit4provided at an upper side of the cavity to manipulate the operation of the electric oven; and a hot plate2provided at an upper side of the electric oven to put a cooker thereon and cook food. However, the electric oven having the cavity without the hot plate2can be used.

FIG. 2is a plan view illustrating a first door opening and closing apparatus according to the present invention, andFIG. 3is a sectional view taken along line I-I′ ofFIG. 2.

FIG. 2illustrates the first door opening and closing apparatus, and can be understood when the latch150and the insertion hole6are horizontally observed.

Referring toFIGS. 2 and 3, the inventive first door opening and closing apparatus includes an upper plate101fixed to any one side of the housing5; a motor110being seated on the upper plate101and rotating in a forward direction or in a reverse direction; a disc-shaped rotary unit120for rotating by a motor shaft111at a lower side of the upper plate101; first and second contact protrusions123and124protruded from left and right peripheries of the rotary unit120; first and second micro-switches131and132being switched on/off by the contact protrusions123and124when the rotary unit120is rotated; and a latch guide140being reciprocated according to a rotary motion of the rotary lever120to lock or unlock the door latch150.

An operation of the inventive door opening and closing apparatus is described in brief. In order to completely lock the door in a state where the door is closed to insert the latch150, the latch guide140is moved forth and back. If the latch guide140is moved to latch the latch150, the door is locked. If the latch150is released, the door can be opened. If the latch150is latched using the latch guide140of the first door opening and closing apparatus, the door is not opened even though a user pulls the door. If the latch150is released using the latch guide140of the first door opening and closing apparatus, the user can pull and open the door.

In detail, the motor110is seated and fixed to the upper plate101. Additionally, the motor shaft111extended from a lower side of the motor110is inserted into a shaft insertion hole121. The shaft insertion hole121is provided at a center of the disc-shaped rotary unit120. The disc-shaped rotary unit120is provided at a lower side of the motor shaft111. Here, the disc-shaped rotary unit120has a guide shaft hole122at a circumference thereof, and has the first and second contact protrusions123and124protruded from a periphery thereof. Further, the rotary unit120has the guide shaft hole122and the contact protrusions123and124, which are disposed at an interval of 120°. The motor shaft111and the shaft insertion hole121have noncircular-shapes to allow a rotary force of the motor110to be transmitted without sliding.

As an example, the motor110and the rotary lever120can be also arrayed in a horizontal direction, not in a layered structure, to transmit a driving force, and can also employ other apparatuses.

Further, the first and second micro-switches131and132are installed adjacently to and outside the rotary unit120. The first and second micro-switches131and132respectively have first and second switch contacts133and134, which contact with the contact protrusions123and124, to be disposed within a rotation radius of the first and second contact protrusions123and124. As an example, the micro-switches131and132and the contact protrusions123and124can be correspondingly changed in position.

Furthermore, the guide shaft141upwardly protruded from one end of the horizontally disposed latch guide140is inserted into the guide shaft hole122of the rotary unit120. Accordingly, the guide shaft hole122guides the guide shaft141to allow the latch guide140to reciprocate with respect to a circular motion of the rotary unit120. For this, the guide shaft hole122is provided to have a relatively long and straight-line shape such that the guide shaft141can move within a predetermined range. Additionally, the latch guide140has at least one latch guide slot142. The latch guide140is guided within a range of a straight-line motion along a fixing guide member, such as a screw143, which is engaged to the latch guide slot142. Additionally, the door latch150is protruded from the other end of the latch guide140in an orthogonal direction. A latch through-hole145is provided at a center of the latch hooking unit144to lock the latch150. As an example, the latch hooking unit144can have an “L”-shape, and can be changed in shape as far as the latch150can be locked and unlocked.

An operation of the door opening and closing apparatus is described.

If a predetermined sensing apparatus senses that the door is closed and the latch150is inserted into the insertion hole6, the motor110rotates to allow a clockwise rotation of the rotary unit120. If the rotary unit120rotates, the latch guide140is pushed up to fit the latch150into the latch through-hole145, thereby fixing the latch150. Additionally, the first switch contact133can be pushed by the first contact123to terminate the rotary motion of the motor110. In this case, pyrolysis operation may be performed to maintain the cavity clean. Alternatively, when the door is attempted for opening, the motor110is rotated in an opposite direction of the above operation.

In detail, locking and unlocking states of the inventive door opening and closing apparatus are described with reference toFIGS. 4 and 5.

FIG. 4is a view illustrating an operation of the unlocking state of the door. If the door is closed, the door switch senses the locking of the door to supply a power to the motor depending on a key signal of a controlling unit. Accordingly, the motor shaft111is rotated in a predetermined direction, and the rotary unit120is engaged at its center to the motor shaft111to rotate clockwise. If the rotary unit120is rotated clockwise, the first contact protrusion123of the rotary unit120presses, at its right side, the first switch contact133of the first micro-switch131to perform a switch-on. At the same time, the clockwise rotation of the rotary unit120causes the latch guide140to perform a straight-line motion to the right. The latch guide140has the guide shaft141inserted into the guide shaft hole122of the rotary unit120. The first switch contact133is switched on to cut off the power supplied to the motor and terminate the operation. At this time, the door latch150is fitted and latched in the through-hole145of the latch hooking unit144, which is protruded from the other end of the latch guide140, to allow the door to be in the locking state.

FIG. 5is a view illustrating the unlocking state of the first door opening and closing apparatus according to the present invention.

When the door is attempted for opening, the motor shaft111rotates counterclockwise. If the rotary unit120is rotated counterclockwise, the second contact protrusion124of the rotary unit120presses the second switch contact134of the second micro-switch132to perform the switching. Additionally, as the rotary unit120rotates counterclockwise, the latch guide140is pulled downward along the screw143fitted into the guide slot142to perform the straight-line motion, and the door latch150is released from the latch through-hole145provided at the other end of the latch hooking unit144. The second switch contact132can be also pressed by the second contact protrusion124to switch off the power supplied to the motor.

As such, the protrusions123and124are provided at the left and right sides of the disc-shaped rotary unit120performing the rotary motion. The rotary force of the motor110and an on/off operation contacting of the first and second micro-switches131and132are sensed. Accordingly, the door latch can be stably operated. In other words, the door is stably locked and unlocked such that when the electric oven performs any operation such as pyrolysis, thereby generating a high heat, a user's safety can be more improved.

The door opening and closing apparatus is an apparatus for preventing the opening of the door to enhance the user's safety. Alternatively, the opening or closing of the door should be reliably sensed to operate the door opening and closing apparatus. An interlocking apparatus of the door is provided as an apparatus for meeting the above requirement. Hereinafter, the interlocking apparatus is described.

FIG. 6is a sectional view taken along line II-II′ ofFIG. 2, and illustrates the interlocking apparatus of the door as the second door opening and closing apparatus. A position and/or a place where the interlocking apparatus is installed can be changed unlike the disclosed embodiment.

Referring toFIG. 6, the interlocking apparatus includes the latch150latched to the door; a latch board220fixed to any position of the housing5; a rotary lever230being rotated, in contact with the door latch150, depending on the opening and closing of the door, and having step switches235and236at ends thereof; the micro-switch240having a plurality of switch contacts for performing an on/off operation depending on the rotary lever230; and an elastic spring237providing a predetermined elastic repulsive force with respect to the rotation of the rotary lever230. The micro-switch240can also employ a plurality of layered micro-switches and a single micro-switch having two contacts. However, it is enough only that contact switches are provided at two vertically spaced-apart positions. The latch150can be also inserted into the insertion hole6.FIG. 7is a sectional view taken along line III-III′ ofFIG. 6. InFIG. 7, a separate micro-switch240is comprised of a monitor switch contact241and a primary switch contact242that are layered up and down.

Alternatively, the latch150can employ a latch having a function of locking the door, but can also employ a separate protrusion being provided at an inner side surface of the door and opposing to a position at which the interlocking apparatus is installed.

An operation of the interlocking apparatus is described in brief.

The door latch150latched with the door pushes the rotary lever230. The rotary lever230rotates about a predetermined center to sequentially operate the monitor switch contact241and the primary switch contact242, which are provided at the micro-switch240. While this operation causes the closing of the door, the monitor switch contact241and the primary switch contact242are sequentially operated in a serial process. By this sequential operation, the closing of the door can be sensed. When the object such as a dinnerware is put in the electric oven, the interlocking apparatus determines that the object is not the door, thereby preventing the object from being erroneously sensed as if the object is the door.

A detailed construction and an operation or effect relating with the detailed construction of the interlocking apparatus are described with reference to the above construction.

If the door is closed, the latch150is inserted into the insertion hole6to push the rotary lever230such that the rotary lever230rotates about the rotary shaft232. A rotary guide protrusion231is engaged to an approximate center of the rotary lever230. Therefore, if the latch150is inserted, it contacts with the rotary guide protrusion231to wholly push the rotary lever230.

Additionally, if the rotary lever230is rotated, the first and second step switches235and236of the step protrusion234, which is provided at a front end of the rotary lever230, sequentially operate the monitor switch contact241and the primary switch contact242of the micro-switch240, which are vertically disposed. In detail, since the first and second step switches235and236are stepped up and down, the first step switch235pushes the monitor switch contact241to perform the switching. The second step switch236pushes the primary switch contact242to perform the switching. Additionally, only in case where the monitor switch contact241and the primary switch contact242are sequentially switched on/off at a predetermined time interval, it is sensed that the switching is performed using the latch150, to determine whether or not the door is normally opened and closed.

FIG. 7is a section view taken along III-III′ ofFIG. 6, andFIG. 8is a plan view illustrating the rotary lever.

Referring toFIGS. 7 and 8, the primary switch contact242and the monitor switch contact241are provided to have different heights at one side surface of the micro-switch240. Additionally, the step protrusion234provided at one end of the rotary lever230is comprised of the first step switch235and the second step switch236that are protrusively stepped in two rows. The first step switch235faces with the monitor switch contact241to perform the switching. The second step switch236faces with the primary switch contact242to perform the switching. Therefore, the plurality of switch contacts241and242pushes the switch contacts241and242within the rotation radiuses of the first and second step switches235and236to perform the switching.

In detail, in a state where the rotary lever220is rotatable about the rotary shaft111, the rotary lever220is engaged at one side to the rotary guide protrusion231and is pressed at the other side by the elastic repulsive force of the elastic spring237. In this state, when the door is closed, the door latch150pushes the rotary guide protrusion231. At this time, the rotary lever230is rotated about the rotary shaft232together. The elastic repulsive force of the elastic spring237is also acted. Additionally, when the rotary lever230rotates, the first step switch235provided at a front end of the step protrusion234presses the primary switch contact241of the micro-switch240to perform the switching. After a predetermined time, the second step switch236presses the monitor switch contact242of the micro-switch240to perform the switching. At this time, the monitor switch240is operated at a time point when the primary switch and the monitor switch are concurrently switched on. Further, only in case where the primary switch and the monitor switch are switched on at a predetermined time interval, it can be recognized that the door is closed. In case where the switch is operated due to the introduction of the foreign substance, the switch is not switched off at a predetermined sequence or at the time interval. Accordingly, it is determined that the door is not closed such that the operation of the electric oven is prevented.

A non-described numeral233denotes a boss fixed to one end of the rotary lever230. A non-described numeral252denotes a boss fixed to one end of the elastic spring237. A non-described numeral238denotes a fixing unit fixed to the other end of the elastic spring237.

FIGS. 9 to 12are views illustrating a sequential latch-inserting operation of the second door opening and closing apparatus.

In an initial state where the latch is inserted, as inFIG. 9, the monitor switch contact241and the primary switch contact242of the micro-switch are switched-off and the door is opened.

FIG. 10illustrates a state where the latch150is gradually moved forth as the door is closed. The latch150pushes the rotary guide protrusion231while the rotary lever230begins to rotate. At this time, the first step switch235, which is provided at the step protrusion234of the rotary lever230, presses the monitor switch contact241such that the monitor switch is changed to be in a switching-on state. However, the primary switch contact242is maintained to be in the off state such that it can be easily determined that the door is not fully closed.

FIG. 11illustrates a state where the latch150is moved a little more forth. The latch150pushes the rotary guide protrusion231while the rotary lever230is pushed a little more thanFIG. 10. At this time, the second step switch236provided at the step protrusion234of the rotary lever230presses the primary switch contact242to change the primary switch contact to be in the switch-on state. The monitor switch contact241is continuously maintained to be in the switch-on state.

FIG. 12illustrates a state where the monitor and primary switch contacts241and242of the micro-switch are in the switch-on states, and the door latch150is fully latched. Therefore, a general operation of the electric oven, which should be initiated after the door is closed, can be initiated. Alternatively, in case where the door is not sequentially closed at a time interval or one switch is not switched-on as inFIGS. 9 to 12, it is determined by the switching-on of the monitor switch contact241and the primary switch contact242that the door is not closed, thereby not initiating the operation of the electric oven. By doing so, the user can use the electric oven under more improved safety.

Alternatively, as the rotary lever rotates clockwise, the elastic spring has a greater elastic repulsive force. Accordingly, the elastic spring can be easily restored in an original state. Therefore, when the door is opened, the rotary lever230is pushed by the repulsive force of the elastic spring237such that the micro-switch240can be switched-off. At this time, it can be also sensed that the door is opened.

Further, when the monitor switch contact241and the primary switch contact242are all switched-on, it can be determined that the door is fully closed. Accordingly, the electric oven can initiate the normal operation, and the door locking apparatus described as the first door opening and closing apparatus can operate.

The door opening and closing apparatus according to the present invention concurrently embodies the first door opening and closing apparatus, and the second door opening and closing apparatus. The first door opening and closing apparatus is provided as the door locking apparatus to lock the door, thereby preventing the opening of the door. The second door opening and closing apparatus is provided as the door interlocking apparatus to accurately indicate the opening and closing of the door. Only in case where it is sensed that the door is fully closed by the second door opening and closing apparatus, the first door opening and closing apparatus can be operated. However, any one door opening and closing apparatus can be selectively employed depending on a detailed application for the electric oven. In detail, the first door opening and closing apparatus is mounted to safely operate the electric oven with the door not being opened. The second door opening and closing apparatus is provided to prevent the operation of the electric oven in a dangerous state caused by a user's unconscious action. However, in case where the first door opening and closing apparatus and the second door opening and closing apparatus are all used, a total scope of the present invention can be safely embodied.

Further, the first and second door opening and closing apparatuses perform the opening and closing operation by a single latch latched with the door, but can perform separate operations by each of latches. At this time, the first door opening and closing apparatus can be a certain apparatus for performing the reliably locking of the door, and the second door opening and closing apparatus can be a certain apparatus for preventing the foreign substance from being recognized as the door.

INDUSTRIAL APPLICABILITY

As described above, the inventive door opening and closing apparatus has an effect in that when the electric oven is erroneously operated, the apparatus can prevent a great disaster, thereby more increasing a safety in use.

In particular, the inventive door opening and closing apparatus has an effect in that when the internal of the cavity reaches a high temperature, the apparatus can prevent the opening of the door caused by a careless use, thereby much more increasing the safety in use.

Further, the inventive door opening and closing apparatus has an advantage in that it prevents the door from being erroneously sensed as if the door is closed due to the foreign substance, a danger of indoor fire is not caused by high heat of the electric oven.

Furthermore, the inventive door opening and closing apparatus has an advantage in that the apparatus is simplified in structure to reduce a manufacture cost and more increase a product application in convenience.