WO2022037645A1

WO2022037645A1 - Air fryer

Info

Publication number: WO2022037645A1
Application number: PCT/CN2021/113521
Authority: WO
Inventors: Matthew Alfred CROWE
Original assignee: Crowe Matthew Alfred
Priority date: 2020-08-19
Filing date: 2021-08-19
Publication date: 2022-02-24

Abstract

An air fryer includes a motor-driven rotor supporting a removable food container for rotation so as to tumble the food and ensure even cooking.

Description

AIR FRYER

Technical field

The present invention relates to cooking devices of the air fryer type that use a high velocity current of hot air to rapidly cook food.

Background of the Invention

Typically, air fryers are electric countertop appliances that comprise a cooking chamber that receives an air-permeable rack or basket for supporting the food, for example potato chips (fries) or chicken. Hot air is blown around and through the food at a relatively high speed, allowing it to be cooked using much less oil than is needed for deep frying, or even using no oil at all.

However, many old air fryers have some of the same drawbacks as conventional ovens, particularly in regard to accessing the cooking chamber. For instance, to allow for safe handling of hot food, a handle may be fixed to the rack or basket, but an adequately sized handle that projects outside the cooking chamber tends to significantly increase the overall dimensions of the appliance. Furthermore, to ensure even cooking, the food needs to be turned and opening the cooking chamber to do this causes heat to be lost and cooking time extended. It is an object of the present invention to overcome or substantially ameliorate the above drawbacks or, more generally, to provide an improved air fryer.

Disclosure of the Invention

According to one aspect of the present invention there is provided an air fryer, comprising:

a housing;

a food container received in the housing, the food container having sidewalls, a bottom wall at one end of the sidewalls and an opposing end of the sidewalls defining a mouth of the food container, wherein the bottom wall and/or sidewalls include an air inlet for passing hot air into the food container;

a fan for inducing an air stream through the air inlet into the cooking chamber;

a heater for heating the air stream;

a rotor supporting the food container for rotation about an axis extending through the bottom wall and mouth of the food container, and

a drive for applying torque to turn the food container about the axis.

By driving the food container to rotate, food items cooked in the air fryer are tumbled and more evenly exposed to the stream of hot air.

Preferably the housing and sidewalls are substantially cylindrical and coaxial with the axis.

Preferably the mouth of the food container is disposed adjacent one axial end of the housing, and a door is fixed to the one axial end is provided for closing the mouth of the food container, and the fan and heater are disposed inside the other axial end of the housing.

Preferably the drive operates to periodically reverse the torque and oscillate the food container.

Preferably the controls are provided to allow the user to select different speeds of oscillation. Optionally, user controls may allow the user to select different angular amplitudes of oscillation.

Preferably the housing comprises an inlet port through which the air stream is drawn and exhaust vents from which it exits the housing. Alternatively, a portion of the air stream may be drawn from inside the housing, thus providing a degree of recirculation.

Likewise, the fan may also induce an air flow that is not heated and does not pass through the air inlet into the food container, and this air flow may be used for cooling purposes inside the housing, as for motor cooling.

Preferably the drive comprises a reversible rotary electric motor connected by a transmission to the food container.

Preferably the transmission comprises a speed-reducing gear pair, a driving gear of the gear pair fixed to an output shaft of the motor, and a driven gear of the gear pair fixed to the food container. However, many alternative types of motorised drive may be used, for instance a belt drive may be used, as with the belt directly engaging the exterior of the sidewall and a pulley turned by the motor, or the food container may be driven directly by the motor.

Preferably the air inlet is disposed in the bottom wall and the axis extends through the air inlet.

Preferably the heater is disposed downstream of the fan in a duct connected between an outlet of the fan and the air inlet to the food container. Preferably the heater comprises a resistance wire heater.

Preferably the air fryer further comprises a base adapted for resting upon a horizontal surface and a pivot connecting the housing to the base to allow for inclining of the housing to vary of an angle of elevation of the axis.

Preferably the housing can be manually inclined. Preferably an anti-rotation arrangement holds the housing at a selected angle of elevation to which it is manually inclined. The anti-rotation arrangement may comprise, for instance, friction in the pivot, or a detent.

Preferably the elevation angle may vary such that the mouth may face upwardly, downwardly or horizontally, as by between + 30° from a horizontal.

Preferably the base comprises a pair of stanchions between which the housing is received and the pivot comprises coaxial axles each connecting a respective one of the stanchions to housing.

Preferably a handle may be fixed to the housing for the purpose of manually inclining the housing about the pivot.

Preferably the transmission further comprises a first coupling part for engagement with a complementary second coupling part on the bottom wall of the food container, the first and second coupling parts being connectable to transmit torque to the food container and dis-connectable to remove the food container from the housing. The coupling parts may comprise axially aligned complementary projections and recesses.

Preferably the door comprises a window.

By mounting the housing to turn about the pivot, when combined with the rotation of the food container about the axis, not only does this supplement the tumbling action but cooked food is readily dispensed by tilting the mouth of the cooking container downward.

Brief Description of the Drawinqs

Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings, wherein:

Figure 1 is a schematic cross section in an upright plane through the housing of an air fryer according to an embodiment of the invention;

Figure 2 is a perspective view of the air fryer;

Figures 3 and 4 are schematic pictorial views of the air fryer of Fig. 2 in which the housing is shown sectioned in a longitudinal upright plane, showing the food container respectively removed from, and inserted into, the housing, and

Figures 5 to 7 are schematic pictorial views of the air fryer of Fig. 2 illustrating different inclinations of the housing relative to the base.

Description of the Preferred Embodiments

Referring to Figs 1 and 2, an air fryer 10 comprises a base 11 adapted for resting upon a benchtop, or like horizontal surface, and which supports a housing 12. The housing 12 is closed by an oven door 13 and holds a removeable food container 14 which defines the chamber in which the food 15 is cooked.

The food container 14 has sidewalls 16 which may be substantially cylindrical and integral with a bottom wall 17 formed an inner end of the sidewalls 16 so to define a mouth 18 of the food container 14 at an opposing outer end of the sidewalls 16. A periphery of the bottom wall 17 may be radiused to smoothly join the cylindrical sidewalls to a planar section 21 of the bottom wall 17. The housing 12 may be substantially cylindrical and coaxial with the sidewalls 16, with the mouth 18 disposed at a front side of the housing 12 where it is closed by the door 13. In this manner an internal annular space 20 is formed between the outer side of the sidewalls 16 and an inner side of the housing 12. An air inlet 22 may be formed centrally in the section 21 for passing hot air into the food container 14 and may comprise a mesh or foraminous section of the wall.

The bottom wall 17 may engage a rotor 23 carried on a bearing 25 for rotation about a central longitudinal axis 25 of the food container 14 extending through the bottom wall 17 and mouth 18. The coupling of the bottom wall 17 and a rotor 23 is described below in more detail with respect to Figures 3 and 4. In addition to the bearing 24 other bearing means may help support the food container 14 to rotate, such as journal blocks (not shown) engaging the sidewalls 16.

For applying torque to turn the rotor 23 and attached food container 14 about the axis 25, a drive may comprises a reversible rotary electric motor 26 with an output shaft 27. A driving gear 28 fixed to the output shaft 27 engages a driven gear 29 which may be formed on the periphery of the rotor 23, the gear ratio providing a speed reduction.

Next to the rotor 23 inside the space 30 at the inner axial end 31 of the housing 12 is a motor-driven blower or fan 32 for inducing an air stream (indicated by the arrows 34) through the air inlet 22 and a heater 33 for heating the air stream. The heater may be of the resistance wire type and disposed downstream of the fan 32 in a duct 36 connected between an outlet 37 of the fan and an opening 35 in the centre of the rotor 23 located opposite the air inlet 22 in the bottom wall of the food container 14. Air supply to the fan 32 is drawn from outside the appliance through an inlet port 38 in the inner axial end 31 of the housing 12. Air drawn in through the inlet port 38 is heated by heater 33 and this hot air passes through the opening 35 and air inlet 22 into the food container 14 where it is forced through the food 15. The air may then pass out of the mouth 18, through the annular space 20 to then exhaust through vents (not shown) in the inner axial end 31 of the housing 12.

A pivot 39 connects the housing 12 to the base 11 and may be aligned horizontally to allow for inclining of the housing 12 to vary of an angle of elevation of the axis 25. The base 11 may comprises a pair of

stanchions

41, 42 between which the housing 12 is received with the pivot 39 comprising coaxial axles 43 each connecting a respective one of the

stanchions

41, 42 to the housing 12. Controls 47 may be mounted to the base 11 for controlling the air fryer, as for the selection of the speed of the fan 32, air temperature and speed of the motor 26 for turning the food container 14. The drive operates to periodically reverse the motor 26 to oscillate the food container 14, and the controls 47 may allow the user to select different speeds of oscillation.

The housing 12 drive operates to periodically reverse the torque and oscillate the food container. The housing 12 may be inclined manually by grasping a handle 40 fixed thereto. An anti-rotation arrangement holds the housing 12 steady at the angle of elevation to which it is manually inclined and may comprise, for instance, friction in the pivot, or a detent. With the housing 12 inclined about the pivot 39 as shown in Fig. 2, such that the mouth 18 is facing upward, the food container 14 is suitably oriented to be filled with food, passed in through the open door 13. The door 13 may comprise a frame 44 that holds a window 45. The frame 44 may be connected to the housing 12 by a hinge 46, as with its hinge axis aligned tangentially relative to the housing 12. A latch (not shown) secures the door 13 closed.

Figs 3 and 4 illustrate the releasable coupling of the bottom wall 17 and rotor 23 in which a first coupling part may comprise four like projections 48 arrayed around the air inlet 22. Complementary recesses 49 of like form comprise a second coupling part and are disposed in axial alignment with each of the projections 48. With the food container 14 moved axially (from the position shown in Fig. 3) into the housing 12 (to the position shown in Fig. 4) the projections 48 are entered into the recesses 49, thereby allowing the transmission of torque from the rotor 23 to the food container 14. In this position, closing and latching of the door 13 secures the food container 14, preventing it moving axially.

Figures 5-7 illustrate some of the different inclinations of the housing 12 relative to the base 1 about the pivot 39. Figs 5 and 7 illustrate opposite extremities of the inclination, with the mouth 18 facing upward and downward respectively, at respective elevation angles 50 of + 30° from a horizontal. Fig. 6 shows an intermediate position with the axis 25 horizontal. It should be understood that the friction or detent action may hold the housing at any intermediate position between those of Figs. 5 and 7.

In use, the handle 40 is pushed backwards to raise the mouth 18 to the position of Fig. 5, such that the mouth 18 is facing upward for filling with food. During cooking, by driving the food container 12 to rotate, food items cooked in the air fryer are tumbled and more evenly exposed to the stream of hot air. This tumbling action can be supplemented by manual inclination of the housing. Also, to visually inspect the food, tilting the mouth 18 forward, as to the horizontal position of Fig. 6, brings the food nearer to the window 44. If the food is cooked, the housing 12 is inclined as shown in Fig. 6 with the mouth 18 facing downward. After placing a dish (not shown) below the mouth 18, the door 13 may then be opened to dispense the food. Combined with the rotation of the food container about the axis 25, the tumbling action also assists in dispensing the food.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof.

Claims

An air fryer, comprising:

a housing;

a food container received in the housing, the food container having sidewalls, a bottom wall at one end of the sidewalls and an opposing end of the sidewalls defining a mouth of the food container, wherein the bottom wall and/or sidewalls include an air inlet for passing hot air into the food container;

a fan for inducing an air stream through the air inlet into the cooking chamber;

a heater for heating the air stream;

a rotor supporting the food container for rotation about an axis extending through the bottom wall and mouth of the food container, and

a drive for applying torque to turn the food container about the axis.
The air fryer of claim 1 wherein the housing and sidewalls are substantially cylindrical and coaxial with the axis.
The air fryer of claim 1 or claim 2 wherein the mouth of the food container is disposed adjacent one axial end of the housing, and a door is fixed to the one axial end is provided for closing the mouth of the food container, and the fan and heater are disposed inside the other axial end of the housing.
The air fryer of any one of the preceding claims wherein the drive operates to periodically reverse the torque and oscillate the food container.
The air fryer of any one of the preceding claims further comprising controls to allow the user to select different speeds of oscillation.
The air fryer of any one of the preceding claims wherein the housing comprises an inlet port through which the air stream is drawn and exhaust vents from which it exits the housing.
The air fryer of any one of the preceding claims wherein the drive comprises a reversible rotary electric motor connected by a transmission to the food container.
The air fryer of any one of claim 7 wherein the transmission comprises a speed-reducing gear pair, a driving gear of the gear pair fixed to an output shaft of the motor, and a driven gear of the gear pair fixed to the food container.
The air fryer of any one of the preceding claims wherein the air inlet is disposed in the bottom wall and the axis extends through the air inlet.
The air fryer of any one of the preceding claims wherein the heater is disposed downstream of the fan in a duct connected between an outlet of the fan and the air inlet to the food container.
The air fryer of any one of the preceding claims wherein the heater comprises a resistance wire heater.
The air fryer of any one of the preceding claims further comprising a base adapted for resting upon a horizontal surface and a pivot connecting the housing to the base to allow for inclining of the housing to vary of an angle of elevation of the axis.
The air fryer of any one of claim 12 wherein the housing can be manually inclined about the pivot.
The air fryer of claim 13 wherein an anti-rotation arrangement holds the housing at a selected angle of elevation to which it is manually inclined.
The air fryer of any one of claims 12 to 14, wherein the elevation angle may vary such that the mouth may face upwardly, downwardly or horizontally, as by between ± 30° from a horizontal.
The air fryer of any one of claims 12 to 15, wherein the base comprises a pair of stanchions between which the housing is received and the pivot comprises coaxial axles each connecting a respective one of the stanchions to housing.
The air fryer of any one of the preceding claims wherein a handle is fixed to the housing for the purpose of manually inclining the housing about the pivot.
The air fryer of claim 7 or claim 8 wherein the transmission further comprises a first coupling part for engagement with a complementary second coupling part on the bottom wall of the food container, the first and second coupling parts being connectable to transmit torque to the food container and dis-connectable to remove the food container from the housing.
The air fryer of any one of the preceding claims wherein the door comprises a window.