WO2010064107A1

WO2010064107A1 - Electric food processor

Info

Publication number: WO2010064107A1
Application number: PCT/IB2009/007576
Authority: WO
Inventors: Man Ping Li; Simeon Jupp; Bengt Ivarsson
Original assignee: Chiaphua Industries Ltd
Current assignee: Chiaphua Industries Ltd
Priority date: 2008-12-05
Filing date: 2009-11-27
Publication date: 2010-06-10
Anticipated expiration: 2011-06-05
Also published as: GB2465834A; GB0822179D0

Abstract

A food processor has a bowl for receiving a food product and an electric motor which drives coaxial drive outputs including a first high speed output for driving a knife and a second contra-rotating low speed output for driving a scraper for skimming a wall of the bowl, which is used for preparing pastes or similar viscous fluids. The first drive output is connected directly to the shaft of the motor, a compact gear train including an epicyclic gear set provides a large speed reduction between the motor and the second drive output. The motor and gear train may be located together in a housing adapted to close the top of the bowl, or the gear train is disposed within a lid which may be connected rotationally fast with the bowl.

Description

Electric food processor

Technical field

The present invention relates to a food processor having a bowl for receiving a food product and an electric motor which drives coaxial drive outputs at different rotational speeds for driving a knife and a scraper for skimming a wall of the bowl.

Background of the Invention

Food processors with electrically driven high-speed rotary knives are commonly used to comminute ingredients to produce powders and pastes. Particularly when producing pastes there is a tendency for the material thrown outwardly by the blades to adhere to the walls of the bowl. With a bowl of a small capacity the volume swept by the blades can be substantially equal to the bowl capacity, so even material adhering to the wall of the bowl is constantly engaged with the knives for good blending performance. However, when increasing the size of the bowl, food processor designers have traditionally considered it necessary to find a trade-off between increased cost on the one hand and reduced performance on the other. Increasing the swept volume of the knives along with the bowl size requires greater torque, requiring a larger motor and hence increasing the cost of the machine, whereas maintaining the same size blade in a larger bowl requires the user to periodically scrape the walls of the bowl to place the material adhering to the wall in the path of the blades, thus compromising the performance of the machine.

UK Patent Application GB2390985 describes a food processor having a motor-driven rotor to which a scraper blade and two tools are mounted. The scraper blade sweeps an outer volume adjacent the upstanding walls of the bowl, and two tools rotate relative to the rotor and sweep an inner volume within the boundaries of the outer volume. In this manner material adhering to the wall beyond the tips of the outermost tool is periodically removed, being picked up by the scraper blade and then falling into the path of the outermost tool. However a drawback with this design is that the tools rotate about the rotor axis at the same speed as the scraper blade, so for high speed operation the rotation of the scraper blade through the material being processed compromises performance and also requires a higher motor output. It is an object of the present invention to overcome or substantially ameliorate the above disadvantages or more generally to provide an improved food processor.

Disclosure of the Invention

According to one aspect of the present invention there is provided a food processor comprising:

a housing;

an electric motor disposed in the housing, the electric motor having a motor shaft with an axis;

a bowl engageable with the housing for receiving food to be processed, the bowl having a base and upstanding side walls symmetrical about the axis;

coaxial drive outputs driven at different rotational speeds, the drive outputs being received in the bowl to rotate tools therein and including a first drive output rotatable about the axis at a highest speed that is suitable for a mixing tool, and a relatively slower, second drive output coaxial with the first drive output;

a gear train to transmit torque between the motor shaft and the second drive output, and

a scraper for skimming the side walls, the scraper being engageable with the second drive output and having a blade portion elongated to lie adjacent the side walls.

The coaxial drive outputs may include any known coupler or dog for torque transmission.

Preferably the blade portion is elongated substantially axially and joined to a hub portion for releasably engaging the second drive output. Optionally the blade portion may be inclined relative to the axis, for instance it may have a helical form to provide axial propulsion to material downwardly as it rotates.

Preferably the blade portion has a cross-section in a transverse plane which is elongated circumferentially.

Preferably the gear train includes at least one epicyclic gear set comprising planet gears meshed with a sun gear and a ring gear, the planet gears being supported upon a planet carrier. Preferably the first drive output and the sun gear are driven directly from the motor shaft and the gear train further includes a first gear coaxial to and rotationally fast with each of the planet gears, the first gears being meshed internally with a second gear and wherein the second drive output is fixed to rotate with the second gear.

Preferably the planet gears and the first gears are integral. Preferably the gear ratio between the planet gears and ring gear differs from that between the first gears and the second gear. Preferably the first and second drive outputs are contra-rotating.

In a first embodiment the gear train is disposed within the housing, the housing defines a closure for closing the bowl and the first and second drive outputs are mounted to the housing, the second drive output including a sleeve portion extending about the first input.

Preferably the first drive output and the sun gear are fixed to the motor shaft.

In a second embodiment the food processor further includes a lid and a mixing tool, wherein

the lid is removably mountable to the bowl for closing the bowl;

the mixing tool has a first end for engaging the first drive output and an opposing second end with a first coupling;

the motor shaft extends through a recess in the base of the bowl;

the first drive output is fixed to the motor shaft, and

the second drive output and the gear train are mounted to the lid and the sun gear is drivingly connected to a second coupling engagable with the first coupling such that with the first and second coupling connected the mixing tool transmits torque from the first drive output to the gear train.

Preferably the sun gear and the second coupling are rotationally fast with an axially extending shaft.

Preferably the second drive output includes a sleeve portion extending about the second coupling.

Preferably the first and second couplings include axially projecting teeth. This invention provides a food processor which is effective and efficient in operational use, and which may be economically constructed. By providing a motorised scraper for the inner walls of the bowl a relatively large bowl can be provided without compromising performance or increasing costs.

Brief Description of the Drawings

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 vertical section through a food processor according to a first embodiment of the invention;

Figure 2 is an exploded pictorial view of the food processor of Fig. 1 ;

Figure 3 is an exploded pictorial view of the gear train of the food processor of Fig. 1 ;

Figure 4 is a section of the scraper along line AA in Fig.1 ;

Figure 5 is a vertical section through a food processor according to a second embodiment of the invention, and

Figure 6 is an exploded pictorial view of the food processor of Fig. 5.

Description of the Preferred Embodiments

Referring to Figs. 1 and 2, a first embodiment of the food processor includes a housing 10 enclosing an electric motor 11. The motor 11 has a drive shaft 12 extending from an inner end thereof and rotating about axis 13. As used herein, the term "axial" refers to a direction substantially parallel to the axis 13. The term "radial" refers to a direction substantially orthogonal to the axis 13. The term "circumferential" refers to the direction of a circular arc having a radius substantially orthogonal to the axis 13.

When assembled for use as shown in Fig. 1 , the bowl 14 is arranged upright with its mouth 15 bounded by rim 16 facing upwardly. The base 18 of the bowl is flat for supporting the bowl on a horizontal surface. The side walls 17 are cylindrical, upright, and coaxial with axis 13. In this manner, food to be processed drops to the base 18 where it is engaged with the knives 19 of a mixing tool 20. Driven to rotate coaxially with the mixing tool 20 is a scraper 21 for removing material adhering to the inner face 22 of the side walls 17. Located in a recess in the centre of the base 18 is a sleeve 54 which receives a locating shaft 71 which extends axially.

The housing 10 includes an upper portion 76 in which the motor 11 is received, it uppermost end located by bracket 23. Mounting plate 24 closes the end of the upper portion 76 and includes a recess for receiving a rotary switch 25 controlling actuation of the motor. A knob 26 is provided to actuate the switch 25. The lower portion 27 of the housing is relatively broader and includes a circumferential shoulder 28 for abutting the rim 16 and an annular flange 29 received within the mouth 15. In this manner the housing 10 closes the mouth of the bowl 14.

Fig. 3 illustrates a bevel gear speed-reduction gear train 75 which includes an epicyclic gear set 30. The epicyclic gear set 30 includes three planet gears 31 meshed with a sun gear 32 and a ring gear 33, the planet gears 32 being supported upon a planet carrier 77. Integral and coaxial with each of the planet gears 31 is a first gear 34. The first gears 34 are meshed internally with a second gear 35. Journals 36 support the planet gears 32 and first gears 34 for rotation about axially aligned shaft portions 37 of the planet carrier 77, and they are held in place by a retaining disc 38 fixed by fasteners 39 to the planet carrier 77.

Referring again to Figs. 1 and 2, the ring gear 33 is rotationally fast, fixed as by engagement with the housing 10 in an interference fit. The sun gear 32 is fixed to rotate with the motor shaft 12. It will be understood that, provided the gear ratio between the planet gears 31 and ring gear 33 differs from that between the first gears 34 and the second gear 35, then the rotation of the sun gear 32 drives the second gear 35 with a substantial speed reduction. In the compact gear train illustrated a speed reduction of 1:400 is achieved.

A first drive output 40 is fixed to the end of the motor shaft 12 and includes a plurality of axially projecting circumferentially spaced teeth 41. A second drive output 42 includes, at an inner end, a recess 43 in which the second gear 35 is received, such that the second drive output 42 rotates with second gear 35. Projecting from an opposing end of the drive output 42 is an octagonal sleeve portion 44. A retaining ring 45 is fixed by fasteners 46 to the housing 10 and serves to connect the second drive output 42 and the housing. The first and second drive inputs 40, 42 are thus collocated inside the upper part of the bowl 14, with the sleeve portion 44 extending about the first input 40.

An annular hub section 47 of the scraper 21 has an internal octagonal face 48 complementary to the sleeve portion 44. Circumferentially spaced around the hub section 47 are resilient hinges 49 each with an inwardly projecting tab 50 which is received in an annular groove in the second drive input 42 providing a detent for securing the scraper. The scraper 21 has a radially extending arm portion 52 that connects the hub section 47 to a blade portion 51 which is axially elongated and lies adjacent the sides walls 17. Having a face complementary to the inner face of the side walls, the blade portion 51 skims the side walls and sweeps a continuous volume adjacent the side walls, such that matter accumulated on the scraper drops to the base 18. The arm portion 52 includes a flange 73 and a radially aligned planar web section 72 that is fixed to the blade portion 51. As best seen in Fig. 4, the blade portion 51 is relatively thin in the radial direction 53, having a cross-section in a transverse plane which is elongated circumferentially.

In an alternative embodiment (not shown) the scraper 21 is moulded from a resilient polymer and an axially and radially extending slot may be provided in the hub section 47. The resulting penannular form allows a degree of resilient deformation of the hub 21 sufficient to allow the second drive output to rotate when rotation of the scraper 21 is blocked, thereby providing limited-slip clutch function for safety.

The mixing tool 20 includes an axially elongated post 56, the lower end of which is connected by fastening assembly 57 to the knives 19. The upper end of the post 56 includes axially projecting teeth 58 for engagement with the teeth 41 for transmitting torque to the tool 20. A blind opening 55 extending through the lower end of the post 56 aligned with an aperture in the knives 19 is provided for receiving the locating shaft 71.

A second embodiment of the food processor is illustrated in Figs 5 and 6 and like reference numbers are used to refer to like components shared with the first embodiment. The housing 110 has a flat base 60 and an upper end 61 that supports the bowl 114 upright. A separate lid 62 closes the mouth 15 of the bowl 114. The lid 62 has a cylindrical flange 68 complementary to the mouth 115 of the bowl. Nubs 69 project radially out from the cylindrical flange 68 and are angularly spaced apart. The mouth 115 includes correspondingly spaced apart L-shaped recesses for receiving the nubs 69, providing a bayonet-type coupling for securing the lid against rotation following a push-turn fastening action.

An axially aligned tubular part 63 of the bowl 114 extends upwardly from the base about an aperture 64. The first drive output 140 is received in the aperture 64 and is fixed to the motor shaft 12. A blind opening 155 in the lower end of the post 156 is complementary to the first drive output 140 for transmitting torque therebetween, for instance, the first drive output 140 and opening 155 may be hexagonal in cross- section.

A first coupling 70 on the upper end of the post 156 comprises teeth 58 projecting axially and a second coupling 64 (having the same form as the first drive output 40) includes complementary teeth 41. The second coupling 64 is fixed to an inner end of an axially extending shaft 65 supported for rotation in journals 66, 67 located in the lid 62 and second drive output 42 respectively. The ring gear 33 is fixed, as by an interference fit, to the lid 62.

The scraper 121 is generally alike the scraper 21 , having an annular hub section 47, radially extending arm section 52 and a blade portion 151 that is relatively thin in the radial direction 51 , having a cross-section in a transverse plane which is elongated circumferentially.

The tool 120 is directly driven by the motor, and transmits torque to the bevel gear speed-reduction gear train 75 fastened to the lid 62, which in turn drives the scraper 121 via the second drive output 42. Both embodiments therefore provide a first drive output 40, 140 driven at motor speed for a mixing tool 20, 120 and a slower speed contra-rotating second drive output 42, 42 for a scraper 21 , 121.

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

CLAIMS:

1. A food processor comprising:

a housing;

2. The food processor of claim 1 wherein the blade portion is elongated substantially axially and joined to a hub portion for releasably engaging the second drive output.

3. The food processor of claim 1 or claim 2 wherein the blade portion has a cross- section in a transverse plane, the cross-section being elongated circumferentially.

4. The food processor of any one of claims 1 to 3 wherein the drive outputs are collocated at an axial end of the bowl.

5. The food processor of any one of claims 1 to 4 wherein the gear train includes at least one epicyclic gear set comprising planet gears meshed with a sun gear and a ring gear, the planet gears being supported upon a planet carrier.

6. The food processor of claim 5 wherein the first drive output and the sun gear are driven directly from the motor shaft and the gear train further includes a first gear coaxial to and rotationally fast with each of the planet gears, the first gears being meshed internally with a second gear and wherein the second drive output is fixed to rotate with the second gear.

7. The food processor of claim 6 wherein each planet gear and respective first gear are integral.

8. The food processor of any one of claims 1 to 7 wherein the first and second drive outputs are contra-rotating.

9. The food processor of any one of claims 1 to 8 wherein the gear train is disposed within the housing, the housing defines a closure for closing the bowl and the first and second drive outputs are mounted to the housing, the second drive output including a sleeve portion extending about the first input.

10. The food processor of any one of claims 1 to 9 wherein the first drive output and the sun gear are fixed to the motor shaft.

11. The food processor of any one of claims 1 to 10 wherein the food processor further includes a lid and a mixing tool, wherein

the lid is removably mountable to the bowl for closing the bowl;

the motor shaft extends through a recess in the base of the bowl;

the first drive output is fixed to the motor shaft, and

12. The food processor of claim 11 wherein the sun gear and the second coupling are rotationally fast with an axially extending shaft.

13. The food processor of claim 11 or claim 12 wherein the second drive output includes a sleeve portion extending about the second coupling.

14. The food processor of any one of claims 11 to 13 wherein the first and second couplings include axially projecting teeth.