US20070114220A1

US20070114220A1 - Electric oven

Info

Publication number: US20070114220A1
Application number: US11/650,892
Authority: US
Inventors: Giuseppe De'Longhi
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-04-08
Filing date: 2007-01-08
Publication date: 2007-05-24
Also published as: US7173217B2; ITMI20040715A1; US20050252905A1; CN100574687C; CN1689492A; FR2868829A1

Abstract

An electric oven has a housing defining a cooking chamber, a door hinged on the housing and pivotal between an open position and a closed position, at least one rotatable rack supported by one of the removable racks, and rotation actuation means for rotating the rotatable rack about an upright axis and positioned peripherally and tangentially to the rack. The rotatable rack has a circular outer edge. The actuation means has a pinion engaged with a circumferential edge surface of the rotatable rack at the edge thereof.

Description

CROSS REFERENCE TO RELATED-APPLICATIONS

This application is a division of copending application Ser. No. 11/102,560 filed 5 Apr. 2005 with a claim to the priority of Italian application MI 2004A 000715 filed 9 Apr. 2004.

FIELD OF THE INVENTION

The present invention relates to an electric oven in particular for cooking or heating food products. In particular, the invention relates to ovens equipped with one or more electrical resistance wires capable of irradiating energy in the form of infrared radiation.

BACKGROUND OF THE INVENTION

In such apparatuses one or more racks are provided, generally in the form of metal wire grids, for directly supporting the food or trays containing food to be cooked or roasted.
One of the drawbacks of conventional cooking apparatuses during cooking consists of the fact that to obtain a homogeneous distribution of heat and an equally homogeneous cooking or browning of the food it is necessary to remove the trays from the cooking chamber to mix the food or turn the trays, involving a waste of energy that is lost with the opening of the door of the apparatus, a lengthening of the cooking times and the need for the operator to be present attending to the food.
In some cooking devices, for example in many microwave ovens, the support plate for the food or for a tray containing the food is made to rotate by a mechanism that has a pulling piston that engages the plate centrally and at the bottom. Such a system could only be implemented in an oven of the type referred to above by eliminating the crumb tray arranged below the resistance wires that produce the heat and therefore would cause a substantial complication of the cleaning operations. Indeed, providing such a system in an oven of the type described above would prevent forward ejection from the crumb tray.
Another drawback of conventional ovens consists of the fact that it allows only a single rack arranged at a predetermined height in the cooking chamber to be removed.
Yet another drawback of conventional ovens is that the ejection system of such a rack can have a substantial metal mass that introduces a thermal inertia that hinders the correct roasting or browning of food.

OBJECTS OF THE INVENTION

An object of the present invention is, therefore, making an electric oven in particular for cooking or heating food that allows the aforementioned technical drawbacks of the prior art to be eliminated.
In this technical task an object of the invention is making an electric oven in particular for cooking or heating food that allows optimal cooking without lengthening cooking times and/or without wasting energy and/or without requiring the operator to be present watching over the food.
Another object of the invention is making an electric oven in particular for cooking or heating food that allows many racks to be removed simultaneously from the cooking chamber without the cleaning operations being penalized and/or without complicating the forward ejection of the crumb tray.
The last but not least object of the present invention is making an electric oven in particular for cooking or heating food that allows the maximum possible flexibility of use by allowing the racks to be interchanged while keeping the functionality of the apparatus unchanged.
The last but not least object of the invention is making an electric oven in particular for cooking or heating food that allows a correct roasting and/or browning of food.

SUMMARY OF THE INVENTION

These and others objects, according to the present invention, are attained by making an electric oven in particular for cooking or heating food, comprising a cooking chamber housing one or more removable racks suitable for supporting said food and slidably engaged with corresponding side guides of said cooking chamber, with at least one rotatable rack supported by one of said removable racks, and with rotation actuation means for the rotatable rack positioned peripherally and tangentially to it.
The present invention also is an electric oven in particular for cooking or heating food, comprising a cooking chamber having one or more removable racks engaged with corresponding guides, and a closing door hinged at the open front side of the cooking chamber, with simultaneous ejection means of the one or more removable racks.

BRIEF DESCRIPTION OF THE DRAWING

Further characteristics and advantages of the invention shall become clearer from the description of a preferred but not exclusive embodiment of the oven according to the invention, illustrated for indicating and not limiting purpose in the attached drawings, in which:
FIG. 1 is a perspective view from the front of a preferred way of making the cooking apparatus of the present invention, in which for the sake of clarity the racks have been removed from the cooking chamber;
FIG. 2 is a perspective view from the front of the cooking chamber of the device of FIG. 1, in which two removable racks are illustrated (with the door of the cooking chamber in closed position) one of which carries the rotatable rack;
FIG. 3 is a perspective view from the front of the cooking chamber of the device of FIG. 1, in which two identical removable racks are illustrated (with the door of the cooking chamber closed) that can be used should it not be necessary to rotate the food to be cooked inside the cooking chamber;
FIG. 4 is a perspective view from an outer side of the cooking chamber of the device of FIG. 1, in which the ejection system is in the configuration with the door of the cooking chamber closed;
FIG. 5 is a different perspective view from an inner side of the cooking chamber of the device of FIG. 1, in which the ejection system is in the configuration with the door of the cooking chamber being open; and
FIG. 6 is a perspective view from an outer side of the cooking chamber of the device of FIG. 1, in which the ejection system is in the configuration with the door of the cooking chamber open.

SPECIFIC DESCRIPTION

With reference to the quoted figures, an electric oven in particular for cooking or heating food products is shown wholly indicated with reference numeral 1. The oven 1 has an outer housing 2 in which a cooking chamber 3 is housed having a front side 4 closed by a door 5 hinged preferably about a horizontal axis arranged substantially at the base of the same front side 4 of the cooking chamber 3. The bottom 6 of the cooking chamber 3 slidably supports a crumb tray 7 that can be removed from the front side 4 of the oven 1 through a slit situated between the bottom 6 itself of the cooking chamber 3 and the door 5. Preferably, the crumb tray 7 in withdrawn position in the cooking chamber 3 extends outside the cooking chamber 3 with a handle 9 for moving it.
In the space between the outer housing 2 and a lateral side of the cooking chamber 3 there are the controls (not illustrated), the operating parameters of which (for example cooking time and temperature) can be controlled by the operator through suitable adjustment knobs 10 on the front side 4 of the oven 1 to one side of the door 5.
Inside the cooking chamber 3, immediately above the crumb tray 7, a first electrical resistance 11 is positioned horizontally suitable for cooking the food. Preferably, at least one second electrical resistance (not shown) is also positioned horizontally immediately below the top side of the cooking chamber 3.
The cooking chamber 3 has pairs of opposite lateral guides 12 in which corresponding removable racks 13 slidably engage, in particular pairs of opposite guides 12 formed as horizontal grooves 14 of the side walls of the cooking chamber 3 and suitable for receiving the side edges of the removable racks 13. Each removable rack 13 consists of one or more metal wire elements 15, rectilinear and/or shaped and/or intertwined and connected to form a grid, since the structure must not hinder a correct and homogeneous distribution of the heat and at the same time must ensure that crumbs or whatever else coming from the cooking and/or roasting of the food can be collected by the tray 7. The removable racks 13 are intended to support the food directly or through a cooking container. At least one removable rack 13, in particular the bottom one, can also be intended to support a rotatable rack 16 that can be made to rotate by suitable actuation means 17 positioned tangentially and peripherally to it (FIG. 1).
The rotatable rack 16, supported by the removable rack 13, is in turn intended to directly or indirectly support the food to be cooked, and it can be made to rotate by actuation means 17 (FIG. 1 only) about a vertical axis substantially passing through its center. In the preferred embodiment illustrated here the rotatable rack 16 has a circular outer edge and a section suitable for supporting, coaxially or fixedly, accessories such as a circular grill 18 (or a pan), of substantially the same diameter. The removable rack 13 intended to support the rotatable rack 16 has at least one first circular metal wire element 37 for supporting the rotatable rack 16, and the first circular wire element 37 is supported from diametrally opposite sides by second and third shaped wire elements 19 in turn slidably engaged in grooves 14 of the side walls of the cooking chamber.
The actuation means 17 preferably has a magnetic motion transmission between a pinion 22 and the rotatable rack 16, which in such a case is metallic. The pinion 22 is therefore made from magnetic material, for example a permanent magnet, and is arranged with its rotation axis horizontal so that its side surface is in contact with the bottom surface of the rotatable rack 16. The pinion 22 is actuated by the shaft of a motor 23 positioned preferably in the space between a side wall of the housing 2 and the adjacent lateral side of the cooking chamber 3, and exerts an attraction on the contact surface with the rotatable rack 16 avoiding sliding thereof. In a different configuration the motor 23 could also be behind the cooking chamber. The magnetic transmission of rotary motion between the pinion 22 and the rotatable rack 16, as well as ensuring perfect effectiveness even when one of the two parts is greasy, is particularly quiet, does not have problems of interlocking and can easily be inspected and cleaned. The magnetic pinion 22 can be made with a cylindrical permanent magnet having opposite poles at its ends, or else with a plurality of magnetic disks and non-magnetic metal disks stacked alternately with two non-magnetic metal disks at the ends. In the second case it is possible to obtain an increase in magnetic flow density through the lateral surface of the pinion 22 and at the same time to limit the force of the magnetic field directed axially.
The transmission of motion between the pinion 22 and the rotatable rack 16 can also be of the mechanical type, in a first case via a high-friction coating of the pinion 22, for example made from rubber, in a second case by providing the pinion 22 with teeth that mesh with a rack extending circumferentially on the rotatable rack 16.
Of course, the rotation of the rotatable rack 16 can be enabled or disabled by the operator through a suitable button that commands the opening/closing of a switch of an electric power supply circuit of the motor 23.
According to another aspect of the invention, the oven 1 has ejection means of the removable racks 13, preferably able to be actuated by the opening/closing of the door 5. Such ejection means comprise a linkage 25 housed in the space between a side wall 27 of the cooking chamber 3 and the housing 2 of the oven 1, preferably in the same space where the motor 23 is found. The linkage 25, which is oriented in a vertical plane, comprises an equalizer lever 26 pivoted at 50 on the side wall 27 and/or to the housing 2 and having a first arm 28 on which is pivoted one end of a connection link 29 also pivoted on the door 5 and a second command arm 30 of a thruster element 31 of the removable racks 13. The link 29 is pivoted on the end of the equalizer lever 26 and on the door 5, in particular at a vertical edge thereof.
The thruster element 31 has a first part 32 outside the cooking chamber 3 and slidably engaged in an L-shaped slot 33 of the second arm 30 of the equalizer lever 26, and a second part 34 inside the cooking chamber 3 and slidably engaged in an opening 35 in particular behind the removable racks 13. The first part 32 of the thruster element 31 is fixed to a substantially vertical rotation axis 38 and has at least one horizontally extending first element 39 engaged with the slot 33. The second part 34 of the thruster element 31 has a second vertically extending element 40 engaged in the opening 35 of the racks 13.
The slot 33 is preferably angular in shape so that the first element 39 is engaged with one of the legs of the slot 33 when the door 5 is open and with the other leg when the door 5 is closed.
The operation of the oven according to the invention is clear from what has been described and illustrated and, in particular, is substantially the following:
Let us suppose that two different foods must be cooked in the oven, one of which, arranged on the rotatable rack 16, needs to be rotated in order to be cooked more homogeneously. After having set the cooking time and temperature and having enabled the rotation of the rack 16, the operator closes the door 5 and switches on the oven.
After the oven has been switched on, the motor 23 periodically or continuously rotates the pinion 22, which transmits its rotation to the rack 16, for rotation of the food supported by it.
At the end of cooking of one or both of the foods, the operator opens the door 5.
During opening of the door 5, the link 29 makes the equalizer lever 26 rotate, the slot 33 of the equalizer lever 26 in turn makes the thruster element 31 rotate, since it is engaged with the first element 39 of the thruster element 31, and the second element 40 of the thruster element 31 goes from a first withdrawn operating position substantially close to the rear of the cooking chamber 3 to a second advanced operating position toward the front of the cooking chamber 3.
Since the element 40 is fixed to the opening 35 of the removable racks 13, as it advances it also drags them forward to the point of partially ejecting them from the cooking chamber 3.
The element 40 comes out from the opening 35 during advancing to definitively free the rack 13.
The unhooking of the element 40 from the racks 13, for example for cleaning or inspection, takes place by pulling the racks 13, which at the end of the opening stroke of the element 40 are disengaged from it.
In the reverse operation, by closing the oven door, the element 40 in its curved return trajectory once again engages in the opening 35 of the removable racks 13 pulling them inside the cooking chamber.
The oven thus conceived can undergo numerous modifications and variations, all of which are covered by the inventive concept; moreover, all of the details can be replaced with technically equivalent elements. In practice, the materials used, as well as the sizes, can be whatever according to the requirements and the state of the art.

Claims

1. An electric oven comprising:

a housing defining a cooking chamber;

a door hinged on the housing and pivotal between an open position and a closed position;

at least one rotatable rack supported by one of the removable racks; and

rotation actuation means for rotating the rotatable rack about an upright axis and positioned peripherally and tangentially to the rack.

2. The electric oven defined in claim 1 wherein the rotatable rack has a circular outer edge.

3. The electric oven defined in claim 1 wherein the actuation means comprises a pinion engaged with a circumferential edge surface of the rotatable rack at the edge thereof.

4. The electric oven defined in claim 3 wherein the actuation means has a magnet coupling the pinion to the rotatable rack.

5. The electric oven defined in claim 4 wherein the pinion consists of a cylindrical permanent magnet, and at least the outer edge of the rotatable rack is made of magnetic metal.

6. The electric oven defined in claim 4 wherein the pinion consists of a plurality of magnetic metal disks stacked alternately with non-magnetic metal disks and ending at opposite ends with one of the non-magnetic metal disks, at least the outer edge of the rotatable rack being made of magnetic metal.

7. The electric oven defined in claim 3 wherein the actuation means has mechanical coupling formations between the pinion and the rotatable rack.

8. The electric oven defined in claim 7 wherein the coupling formations include a high-friction coating on the pinion engageable with the circumferential edge surface.

9. The electric oven defined in claim 3 wherein the coupling includes teeth on the pinion meshing with a rack formed along the circumferential edge surface.

10. The electric oven defined in claim 3 wherein the pinion has a horizontal rotation axis.

11. The electric oven defined in claim 3 wherein the actuation means comprises a rotation actuation motor of the pinion in a space between a casing of the oven and a lateral outside wall of the cooking chamber.

12. The electric oven defined in claim 1, further comprising:

guides in the chamber; and

a rack slidable inside the housing on the guides.