Patent Application
20080296421
The present invention relates to apparatus for disintegrating food waste and particularly to such apparatus including a rotor to which blades are fixed.
For use in a kitchen a waste disposer must be sufficiently versatile to satisfactorily process not just soft materials or viscous materials (such as fruit or cooked cereals) but also hard and tough materials (such as some vegetables and bones). Particularly in processing these latter materials the duration of grinding required is an important consideration in the design of a disposer.
Food waste in a conventional food waste disposer is forced by blades on a rotating grinding plate against teeth of a stationary grinding ring. Reduced processing times could be achieved if this action could be improved.
Additional time is also required, for example, if harder food fragments such as carrot and bone pieces rotate at the same speed as the grinding plate without being ground. This results in increased noise and vibration, as well as residual food left in the grinding chamber after the disposer is turned off. Over time, this residual food may cause unpleasant odours.
A further problem in designing a food waste disposer is jamming which occurs when hard objects such as bones enter the food waste disposer and get stuck between the blades of the rotating grinding plate and the stationary shredder ring.
It is an object of the present invention to overcome or substantially ameliorate the above disadvantages or more generally to provide an improved apparatus for disintegrating food waste.
According to one aspect of the present invention there is provided a food waste disposer comprising:
a waste receptacle having a base;
a grinding plate mounted at the base of the waste receptacle for rotation about an axis;
apertures in the grinding plate for the passage of waste;.
at least one blade mounted to the grinding plate for travel toward and away from the axis;
a grinding ring about the periphery of the grinding plate for cooperating with the blade to disintegrate the waste, and
inner and outer stop means engaging the blade at radially inner and outer travel limits of the blade respectively, the outer stop means engaging the blade as it is thrown outward by rotation of the grinding plate.
Preferably the blade is slidably engaged with guide means fixed to the grinding plate. The guide means preferably restrain the blade to move linearly, more preferably the guide means restrain the blade to move radially, most preferably the guide means restrain the blade to move radially parallel to a plane of the grinding plate.
Preferably the blade has at least one tooth having a leading face facing in a direction so as to confront materials to be disintegrated when the grinding plate is rotated, the leading face facing in the direction of rotation of the blade; a receding surface which extends away from the leading face in a direction directed outwardly from a tangent line, the receding surface having shear edges radially outward of the leading face for shearing waste.
The tooth preferably projects from the grinding plate substantially in the axial direction and includes a receding surface which extends away from the leading face in a direction directed axially outwardly from the leading face.
Preferably the guide means include upstands formed by stamping of the grinding plate. The blade preferably includes an elongate mounting portion extending in the radial direction from the tooth to an inner abutment, a saddle overlying the mounting portion and fixed to the grinding plate such that the abutment and tooth abut the saddle to limit the travel of the blade and provide the inner and outer stop means respectively.
Preferably two blades are mounted to the grinding plate for coaxial radial movement on opposing sides of the axis.
This invention provides a food waste disposer which is effective and efficient in operational use which, compared to comparable prior art disposers reduces processing times, especially for harder food fragments. The disposer is also less prone to jamming and moreover the device has an overall simple design which minimizes manufacturing costs and maximizes performance and reliability.
Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings, wherein:
a and 4b are pictorial views of a blade of the grinding plate of the assembly of
Referring to the drawings, particularly
As best seen in
The grinding plate 3 is a metal plate (for instance of stainless steel) and each of the upstands 12a-12h is formed by shearing and bending a section of the plate in a stamping operation. The upstands are arranged in two rows on either side of a radially-extending line 13 that bisects the grinding plate 3 and in sets of four symmetrically positioned either side of a line 14 bisecting the grinding plate perpendicular to line 13. Guide faces 15a-15d on each of the upstands 12a-12d are coplanar and parallel to the line 13 while respective opposing guide faces 15e-15h of the upstands 12e-12h offset to the other side of line 13 are also coplanar and parallel to the line 13.
Each of the blades 10a, 10b has an elongate mounting portion 18 extending in the radial direction and having parallel edges 16a, 16b that are received between the guide faces 15a-15h. A slot 80 parallel to the edges 16a, 16b in the base of the blades 10a, 10b reduces the contact area between the blades and the face 11, leaving the blades 10a, 10b supported upon coplanar support surfaces 17a, 17b. In this manner the blades 10a, 10b are restrained to move radially parallel to a plane of the grinding plate 3.
At the outer end of the mounting portion 18 a tooth 19 extends in the axial direction away from the face 11. The tooth 19 has a leading face 20 facing in the direction of rotation of the blade and aligned perpendicular to the tangent line 21 and to the support surfaces 17a, 17b so as to confront materials to be disintegrated when the grinding plate is rotated.
A receding surface 22 extends away from the leading face 20 to the trailing face 81 in a direction directed outwardly from the tangent line 21. The receding surface 22 is stepped, having first and second shear edges 24 radially outward of one another and of the leading face 20 for shearing waste.
The leading edge of the tooth 19 is chamfered to produce a planar chamfer face 26 extending away from the leading face 20 and inclined obliquely to the leading face 20 toward the axial end surface 28 on the axial tip of the tooth 19. The end surface 28 is planar and substantially parallel to the support surfaces 17a, 17b. Extending outwardly from the end surface 28 an upper oblique surface 27 is planar and inclined acutely to the end surface 28.
At the inner end of the mounting portion 18 an inner abutment nub 25 is formed, having an abutment face 46 on an outer side thereof. The abutment face 46 is positioned opposite an abutment face 27 formed on the tooth 19. At radially inner and outer ends of the blades 10a, 10b are arcuate surfaces 39, 41 respectively. The surface 39 is complementary to the cylindrical hub 40 and the surface 41 has the same radius of curvature as the peripheral edge 34.
A saddle 28 made, for instance, of corrosion-resistant steel has a symmetrical shape comprising parallel legs 29 joined by a web 30 to form a U-shape. The concave side 31 is complementary to the mounting portion 18 providing a sliding fit therebetween. The saddles 28 are permanently fixed to hold the blades 10a, 10b in place by rivets 90 extending through openings 32a-32d in the grinding plate 3. The nub 25 and tooth 19 provide stop means, the faces 46, 47 abutting the saddle 28 to limit the travel of the blades 10a, 10b.
Through-extending apertures 36 are provided in the grinding plate 3 for the passage of waste. Two protrusions 35a, 35b are formed in diametrically opposite positions in the plate by a stamping operation. The protrusions 35a, 35b have a smooth convex surface bounded by an irregular quadrilateral-shaped edge. A projecting lug 37 is formed in like manner to the upstands 12a-12h by shearing and bending a section of the plate in a stamping operation. Notches 38a-38c in the peripheral edge 34 provide additional cutting surfaces. The notches 38a-38c, lug 37 and protrusions 35a, 35b, like the blades 10a, 10b assist in breaking up the waste and driving it outwardly against the grinding ring 7.
When the grinding plate 3 is stationary the blades 10a, 10b are free to move radially, for instance, in response to water or waste being directed into the grinding chamber 1. In operation, rotation of the grinding plate 3 serves to throw the blades 10a, 10b outwardly, the nub 25 abutting the saddle 28 in a position where the arcuate surface 41 is radially aligned with the edge 34 adjacent the grinding ring 7. Material entering the tapering space between the receding face 22 and the grinding ring 9 tends to push the blade inwards, and in addition to the reaction forces acting to disintegrate the waste, clamping action may be provided, the blades holding the waste against the teeth 9 of the grinding ring 7.
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.
