Abstract:
A feeding tube ( 101 ) is presented for conveying a food article to a food processing tool ( 104 ). The feeding tube ( 101 ) comprises an inlet opening ( 107 ) and an outlet opening ( 108 ), and an inner wall ( 112 ) connecting the inlet opening ( 107 ) and the outlet opening ( 108 ). The feeding tube&#39;s inner wall ( 112 ) defines a passage ( 111 ), through which a food article is conveyable in a conveying direction ( 109 ) from the inlet opening ( 107 ) to the outlet opening ( 108 ). The inner wall ( 112 ) has an adjustable inner wall portion ( 118 ) for adjusting a cross section (A 2 ) of the passage ( 111 ) in a direction having a component perpendicular to the conveying direction ( 109 ), which inner wall portion ( 118 ) is adjustable irrespective of the food article being present. The adjustable inner wall portion ( 118 ) is integrated with the feeding tube ( 101 ). The minimum passage cross section (A 2 ) of the feeding tube ( 101 ) can be changed in a user friendly way without the need for a variety of parts being difficult to store and prone to loss.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a feeding tube for conveying a food article to a food processing tool, the feeding tube comprising an inlet opening and an outlet opening, an inner wall connecting the inlet opening and the outlet opening, said inner wall defining a passage, having a passage length, through which a food article is conveyable in a conveying direction from the inlet opening to the outlet opening. 
         [0002]    The invention further relates to a food processor having a housing, a food processing tool, provided in said housing, for processing a food article, and a feeding tube for conveying a food article to be processed to the food processing tool. 
       BACKGROUND OF THE INVENTION 
       [0003]    Food processors having a feeding tube for conveying food articles to food processor processing means are widely known. In general, feeding tubes have an inlet opening in which the food article is to be inserted, and an outlet opening for delivering the food article to the processing means, the inlet opening and the outlet opening being connected by a passage allowing the food article to be conveyed from the inlet opening to the outlet opening. Feeding tubes have to comply with health and safety legislation in most countries. Due to this legislation there is a relation between the height of the feeding tube and the cross section of the passage through which the food is conveyed. This implies that when a large passage cross section is required, e.g. to allow reasonably large food items to be conveyed, a tall feeding tube must be constructed. Ease of use of the food processor requires the feeding tube to allow passage of such reasonably large food articles, reducing the need to cut the food article into small pieces before the food article can be processed. The passage cross section is therefore rather large. However, when small food articles are to be processed, a feeding tube with a smaller passage cross section can be beneficial. It would therefore be desirable if the feeding tube passage cross section could be changed. 
         [0004]    German Offenlegungsschrift DE 2 302 943 discloses a feeding tube in which an insert can be placed to reduce the feeding tube&#39;s passage cross section. A comparable approach is taken in the French patent application FR 2 681 279, which identifies the problem that the feeding tube is only rarely well adapted for the food article to be processed. This latter patent document suggests to provide multiple insert tubes having different inner diameters to be inserted in the feeding tube. The user has to insert the insert tube most suited for the size of the food article to be processed before inserting a food article into the feeding tube. When food articles of different sizes have to be processed, this requires the user to assess the suitability of the insert tube and possibly change the insert tube before the next food article can be processed. This is a tedious task for the user and slows down the processing. Furthermore the approach of FR 2 681 279 requires a manifold of insert tubes. 
         [0005]    These known approaches require separate insert bodies to create different feeding tube passage cross sections. When a number of different feeding tube passage cross sections are required, a variety of different insert parts is required as well. This leaves the user with a large number of parts which are prone to loss and the task of selecting the appropriate insert part for the food article to be processed. Furthermore, each part requires storing volume in for example a kitchen closet. 
       SUMMARY OF THE INVENTION 
       [0006]    It is an object of the invention to provide a feeding tube of which the minimum passage cross section can be changed in a user friendly way without the need for a variety of separate insert parts being difficult to store and prone to loss. 
         [0007]    The object of the invention is realized by the feeding tube as defined in claim  1 . Particularly, the feeding tube according to the invention includes an inner wall comprising an adjustable inner wall portion for adjusting a cross section of the passage in a direction having a component perpendicular to the conveying direction, which inner wall portion is adjustable irrespective of the food article being present. 
         [0008]    When a user requires one or more food articles to be processed using a food processor configuration comprising the feeding tube of the invention, he or she first sets up the food processor so that it is ready to operate. This might include connecting the feeding tube of the invention to the food processor in case a removable feeding tube is used. In other cases, the feeding tube might already be connected to the food processor. The latter being self-evident when a food processor with a non-removable feeding tube is used. A food processor can be any device processing food articles, e.g. a slicer, juicer, grater, blender, chopper, masher or a device offering a combination of food processing possibilities. Depending on the size of the food article to be processed, the user can choose to adjust the cross section of the passage in a direction perpendicular to the conveying direction, i.e. to adjust a reduced passage, by adjusting the adjustable inner wall portion such that the food article to be processed fits well into the feeding tube&#39;s passage. The cross section can be adjusted for the entire passage length between the inlet opening and the outlet opening, or for a part of the passage length without deviating from the invention. The minimum cross section of the passage can be defined as that cross section, considered in a direction perpendicular to a longitudinal axis of the feeding tube&#39;s passage, which is smallest when taking into account the entire passage from the inlet opening to the outlet opening. In the remainder of this document, the term passage cross section will denote the minimal passage cross section unless stated otherwise. When using the feeding tube of the invention, the user can easily adjust the passage cross section to the food article to be processed. This adjusted passage provides an optimal passage for the relevant food article, allowing the user on the one hand to feed the food article without any difficulties into the feeding tube, and on the other hand to limit the play of the food article in the passage during processing. The limited play of the food article in the feeding tube&#39;s passage prevents the food article from bouncing around the passage during processing. Different kinds and/or sizes of food articles to be processed may require different minimum cross sections. The processing of the food article in a food processor typically involves high-speed rotating food processing tools. Such tools, for example a slicing knife or a grating disc, exert forces on the food article being processed. In the undesired situation that the food article has much play in the feeding tube&#39;s passage, said forces will cause the food article being processed to spin and/or bounce around the passage of the feeding tube. Due to these movements of the food article, the end result of the food processing can be influenced. For example, when slicing a food article, such as a carrot, cucumber or the like, the slices become irregular, which can be very inconvenient if the user intends to have regular slices, e.g. to make a well presented salad. Also, the bouncing of a food article can produce quite a lot of sound, especially when hard food articles are to be processed. In cases where the food article bounces violently, the user might develop some fear of using the food processor. However, when the food article is processed using a feeding tube according to the invention, the user can use the adjustable inner wall portion to create a feeding tube passage in which the food article fits nicely. Therefore, the food article has almost no space for bouncing and a more controlled end result is reached. When for example the food processor is used for slicing a food article, the slices will all be of a regular form. 
         [0009]    As the adjustable inner wall portion is integrated with the feeding tube, no loose parts are needed for adjusting the passage cross section. Therefore, no parts can get lost or require storage space in for example a kitchen closet. It is very convenient for the user not to have separate parts to insert into the feeding tube as required by the prior art. Not only as no parts can get lost or require a search before being located, but also as the user does not have to spend time to correctly place the insert in the feeding tube passage. While the food article is being processed, the user might use a pusher to force the food article through the passage as is widely known in the art. 
         [0010]    In an advantageous embodiment the minimum cross section of the passage is continuously adjustable. In such an embodiment, the user can adjust the cross section of the passage such that is has an optimal size for the food article to be processed. 
         [0011]    In a preferred embodiment of the feeding tube according to the invention, the passage is variable in length. In such an embodiment, the passage length can for example be adjusted to the length of the food article to be processed. E.g. a short food article, like a tomato, can be conveyed to the food processing tool using a shorter passage, i.e. a passage having a smaller height, while a long food article, e.g. a cucumber, can be conveyed using a longer passage, i.e. a passage having a larger height. Adjusting the height of the passage to the food article to be conveyed can lead to an improved control of the conveying process. Generally speaking, the inner wall of the passage limits the movement of the part of the food article in the passage. In, for example, the case of a larger food article being conveyed, when only a relatively small portion of the food article is in the passage, encompassed by the feeding tube&#39;s inner wall, the end of the food article outside the passage can cause the food article to be top heavy and fall out of the passage. When the food article is encompassed by the feeding tube&#39;s inner wall, such falling out of the passage is not possible or at least unlikely. This saves the user from re-inserting the food article in the inlet opening and cleaning up any mess made by the food article falling out of the passage. On the other hand, when considering small food articles, a variable length of the passage can be advantageous for controlling the conveying of the food article. For example, when a small food article gets stuck in the passage relatively far away from both the inlet opening and the outlet opening, changing the passage length allows the user to get closer to the stuck food article. This will allow an easy removal of the stuck food article. A passage having a variable length contributes to the user-friendliness of the feeding tube. 
         [0012]    In a practical embodiment of the feeding tube according to the invention the length of the feeding tube is coupled to the passage length. Accordingly, the feeding tube length is changes when the passage length is changed. A variable feeding tube length is advantageous e.g. when storing the feeding tube as a feeding tube with a reduced length requires less space for storage. Therefore the user friendliness of the feeding tube is increased. 
         [0013]    In a preferred embodiment of the feeding tube according to the invention an adjustable wall portion comprising a slideable body for changing the distance between the adjustable wall portion and an inner wall portion opposite the adjustable wall portion. This type of adjustable inner wall portion is easy to implement and thereby reduces design and manufacturing costs. The slidable body can be can be made of any hard material, especially metals (e.g. aluminum, copper, stainless steel, or the like), or hard plastics. To improve the cleanability of the slidable body, it can be coated with a smooth material, for example polytetrafluoroethylene (PTFE), a nano-coating or a sol-gel material. This coating can also improve the slideability of the sliding body. 
         [0014]    In a preferred embodiment of the feeding tube according to the invention in which the feeding tube has a variable passage length, the adjustable wall portion comprises a deformable body deformable by, during use, changing the passage length, wherein the deformable body, based on its state of deformation, determines the distance between the adjustable wall portion and an inner wall portion opposite the adjustable wall portion. This embodiment allows the passage length to be reduced, which can lead to a shorter feeding tube length which requires less storage space than traditional feeding tubes. 
         [0015]    In a practical embodiment the deformable body is chosen such that the relation between the passage length and the feeding tube height of the one hand, and the passage cross section on the other hand satisfies the health and safety regulations applying. This can e.g. be realized by using a deformable body of substantially constant volume. In many countries health and safety regulations require that the minimum cross section of a food processor feeding tube to be related to the feeding tube height in order to prevent fingers or other parts of the user&#39;s hands to reach the food processing tool and thereby preventing the user from getting injured or mutilated. 
         [0016]    In a preferred embodiment of the feeding tube according to the invention, the feeding tube comprises a first part and a second part, wherein the first part and second part are mutually moveable for varying the passage length Moving two parts with respect to each other is a very user friendly way of changing the passage cross section for creating the most suitable passage cross section. From everyday experience the user already has the expectation that when compressing a body in a first direction, it will expand in a second direction substantially perpendicular to this first direction. This is for example the case when a football, tennis ball or the like is pressed. Changing the cross section of the passage by moving two parts with respect to each other is thus also very intuitive. The deformable body can be made of e.g. a thin, pliable sheet of material like metal, rubber, plastic or the like. Alternatively, the deformable body might comprise a bag filled with some fluid, or a solid piece of flexible material. 
         [0017]    In a practical embodiment the first part and the second part both constitute the feeding tube shaft, e.g. the upper and the lower part of the feeding tube shaft. By mutually moving these parts, the length of the feeding tube as seen in a direction along a longitudinal axis of the feeding tube will be adjusted as well. This has the advantage that it is easy for the user to store the device in a kitchen closet or the like by adjusting the feeding tube length to its minimum. 
         [0018]    In a preferred embodiment of the feeding tube according to the invention the first part and the second part are slidably mounted with regard to each other for mutual moving. This type of configuration is especially user friendly as a good structural relation between the first part and the second part is maintained while changing the passage cross section. 
         [0019]    In a practical embodiment the user can slide the first part and the second part to any position between the position in which the distance between the adjustable wall portion and an inner wall portion opposite the adjustable wall portion is maximized and the position in which this distance is minimized, thereby allowing the user to select the passage cross section most suited for the food processing task at hand. 
         [0020]    In a practical embodiment of the feeding tube according to the invention, the first part and the second part are mutually mounted by means of a screw connection for mutual moving. A screw connection implies a spiral line of movement of the first part and the second part with regard to each other and leads to a longer path length over which the first part and the second part are moved with respect to each other between the minimum and the maximum distance between the adjustable wall portion and an inner wall portion opposite the adjustable wall portion when compared with a straight line of movement. The amount of change in said distance per unit of path length when applying a screw connection is smaller than when applying a straight line of movement. This allows the user to select the passage minimum cross section more precisely and also requires less force to be applied by the user to change the passage minimum cross section, thereby improving the user friendliness of the feeding tube. 
         [0021]    In a preferred embodiment of the feeding tube according to the invention the first part and the second part are releasably lockable in their relative positions. When the first part and the second part are locked, the user does not need to hold the first part and/or the second part to maintain the desired passage cross section while using the feeding tube, thereby allowing the user to use both hands to feed food articles to the feeding tube, or e.g. to control the food processor while feeding food article. This further improves the user friendliness of the feeding tube of the invention. 
         [0022]    In a practical embodiment of the feeding tube according to the invention the feeding tube is provided with a detents and notches structure for releasably locking the first part and the second part in their relative positions. A detents and notches structure is an easy to manufacture way to realize a releasably lockable configuration. 
         [0023]    In a preferred embodiment of the feeding tube according to the invention the adjustable wall portion comprises at least one inflatable body, which inflatable body, depending on its state of inflation, determines the distance between the adjustable wall portion and an inner wall portion opposite the adjustable wall portion. This embodiment does not require parts of the adjustable inner wall portion to slide against each other or against other parts of the inner wall or the feeding tube, thereby reducing wear. 
         [0024]    In a preferred embodiment of the feeding tube according to the invention the adjustable inner wall portion has a profile, being in the passage, which profile increases, seen in a direction along the conveying direction from the inlet opening to the outlet opening. Having such a profile, the adjustable inner wall portion will act as a guiding element for the food article to be processed. This reduces the effort the user has to make to position the food article correctly with respect to the passage cross section, improving the user friendliness of the feeding tube. 
         [0025]    In a preferred embodiment of the feeding tube according to the invention the feeding tube has a control unit located on its outer side for controlling the adjustable inner wall portion. A control unit on the outer side of the feeding tube is easy to access for the user as the user does not have to put his or her fingers inside the feeding tube passage to adjust the adjustable inner wall portion. Furthermore, the control unit on the outer side of the feeding tube is likely to stay clean during use of the feeding tube, while the inner side of the feeding tube can get soiled during use. Having a control unit on the outer side of the feeding tube improves its user friendliness and ease of use. 
         [0026]    In a preferred embodiment of the feeding tube according to the invention the feeding tube further comprises an actuator for non-manually actuating the adjustable inner wall portion. Such an actuator relieves the user from the burden of manually operating the adjustable inner wall portion. This contributes to the ease of use and user friendliness of the feeding tube. This is especially true for users which have only limited abilities to operate the adjustable inner wall portion by hand, e.g. elderly users which have lost power in their hands, or persons with disabilities like spasms or a disease like rheumatism. 
         [0027]    In preferred embodiment of the feeding tube according to the invention the actuator comprises an electric actuator unit. Electric motors are cheap and well-known components of kitchen appliances. Implementing an electric motor, i.e. an electric actuator unit, as part of the actuator leads to comparatively low design and manufacturing costs as design staff is well aware of the practicalities of implementing electric motors. 
         [0028]    In a preferred embodiment of the feeding tube according to the invention further comprises a measurement unit for measuring the size of a food article, during use inserted into the feeding tube passage, and a control unit for controlling the actuator for actuating the adjustable inner wall portion, wherein the control unit, during use, controls the actuator to adjust the adjustable inner wall portion to the size of said food article measured by the measurement unit. Automatic adjustment of the passage cross section based on measurement of the size, e.g. the cross section of the food article as seen in a direction perpendicular to the conveying direction, relieves the user from the burden of adjusting the passage cross section and adapting it when the cross section of the food article changes, e.g. when a food article has a changing cross section along its longitudinal axis which is the case when feeding for example a pear, piece of apple, or the like, or when different food articles being processed after each other have a different cross section. The passage cross section is thus automatically adjusted to the what is needed when processing a given food article. 
         [0029]    The invention further relates to a food processor having a housing, a food processing tool provided in said housing, for processing a food article, and the feeding tube according to the invention cooperating with said housing. 
         [0030]    In a preferred embodiment of the food processor according to the invention, having a housing, a food processing tool, provided in said housing and configured for processing a food article, a feeding tube according to the invention comprising an actuator for non-manually actuating the adjustable inner wall portion, said feeding tube arranged for cooperating with said housing, and a user interface for controlling the food processor, the actuator is controlled via the user interface. In this configuration the user is able to control both the food processor and the feeding tube passage minimum cross section from one user interface. This simplifies operation of the food processor, making the food processor more user Friendly 
         [0031]    With reference to the claims it is noted that the invention also relates to all possible combinations of features and/or measures defined in the various claims. 
         [0032]    It is to be noted that the patent application WO 2007/080571 A2 discloses a food processing device having a feeding tube comprising a plurality of so-called fingers which are radially displaceable leaf springs located near the end of the feeding tube near to the food processing tool. These fingers are located on the inside of the feeding tube in its passage and are manipulated by the food article being moved through the passage. Contrary thereto the feeding tube according to the invention comprises an adjustable inner wall portion that can be actuated fully independent from the moving food article, but under full control of the user. The feeding tube according to the invention allows adjustment of the adjustable wall portion irrespective of the presence of a food article. The user can actuate the device by direct manual manipulation. Alternatively, magnetic and/or electric actuators can be used. The use of air or hydraulic pressure, or many other ways of actuating the adjustable inner wall portion are feasible as well. 
         [0033]    It is to be noted that German patent document DE-A-10 2007 021 371 discloses a hopper comprising a hingeable wall element for releasing articles stuck in the hopper. The moveable wall element is not disclosed to be suited to adjust the cross section to limit play of the food article during processing as its main purpose is to create play in order to release the stuck food article. 
         [0034]    It is further to be noted that US patent document U.S. Pat. No. 4,624,030 discloses a stuffing machine having a supporting device for releasably embracing a portion of the stuffed material. During the embracing the portion of the stuffed material is rotated relative to another part of the stuffed material. While being held in embrace, the stuffed material cannot move in the device disclosed by U.S. Pat. No. 4,624,030. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0035]    A detailed description of the invention is provided below. The description is provided by way of a non-limiting example to be read with reference to the drawings in which: 
           [0036]      FIG. 1A  shows a first schematic side view, partly cut, of a first embodiment of the feeding tube according to the invention, connected to a food processing device. 
           [0037]      FIG. 1B  shows a second schematic side view, partly cut, of the first embodiment of the feeding tube according to the invention as shown in  FIG. 1A . 
           [0038]      FIG. 2A  shows a first schematic bottom view, partly cut, of the first embodiment of the feeding tube according to the invention as shown in  FIG. 1A . 
           [0039]      FIG. 2B  shows a second schematic bottom view, partly cut, of the first embodiment of the feeding tube according to the invention as shown in  FIG. 1A . 
           [0040]      FIG. 2C  shows a third schematic bottom view, partly cut, of the first embodiment of the feeding tube according to the invention as shown in  FIG. 1A . 
           [0041]      FIG. 3A  shows a first schematic side view, partly cut, of a second embodiment of the feeding tube according to the invention, connected to a food processing device. 
           [0042]      FIG. 3B  shows a second schematic side view, partly cut, of the second embodiment of the feeding tube according to the invention as shown in  FIG. 3A . 
           [0043]      FIG. 4A  shows a first schematic side view, partly cut, of a third embodiment of the feeding tube according to the invention, connected to a food processing device. 
           [0044]      FIG. 4B  shows a second schematic side view, partly cut, of the third embodiment of the feeding tube according to the invention as shown in  FIG. 4A . 
           [0045]      FIG. 5A  shows a first schematic side view, partly cut, of a fourth embodiment of the feeding tube according to the invention, connected to a food processing device. 
           [0046]      FIG. 5B  shows a second schematic side view, partly cut, of the fourth embodiment of the feeding tube according to the invention as shown in  FIG. 5A . 
           [0047]      FIG. 6A  shows a first schematic top view, partly cut of the fourth embodiment of the feeding tube according to the invention. 
           [0048]      FIG. 6B  shows a second schematic top view, partly cut, of the forth embodiment of the feeding tube according to the invention as shown in  FIG. 6A . 
           [0049]      FIG. 7  shows a schematic front view of a first embodiment of the food processor according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0050]    In figures showing the same embodiment or the same parts thereof, the same numbers are used for the same parts. 
         [0051]      FIG. 1  shows a feeding tube  101  attached to a food processor  102  of which only its top part, namely the upper side of its housing  103 , the food processing tool  104  and the drive shaft  105  which drives the food processing tool  104  during operation, are visible. Not shown in  FIG. 1  is a power unit which powers the drive shaft. Such power units, e.g. an electric motor, are well known from the art, as is their construction within a food processor. In this particular case the food processing tool  104  is a slicing knife. Other types of food processor tools are known, e.g. grating disks, chopping disks, mashing disks, et cetera, and can be implemented with the feeding tube  101  alike. Feeding tube  101  has a longitudinal axis  106 , an inlet opening  107 , and an outlet opening  108 . The inlet opening  107  and outlet opening  108  are connected by a passage  111  defined by an inner wall  112  of the feeding tube  101 . During use, a food article to be processed (not shown) is introduced into the feeding tube  101  through inlet opening  107 . In this embodiment, the inlet opening  107  and outlet opening  108  are located on the longitudinal axis  106 . In other embodiments, one or both of these openings may be located in a feeding tube side wall. Along passage  111  the food article is directed, e.g. by a pusher unit (not shown) or other suitable device known in the art, towards the outlet opening in a conveying direction  109 . In the specific embodiment of  FIG. 1A  the food article will move from the inlet opening  107  to the outlet opening  108  under influence of gravity as well, possibly removing the need for the user to use a pusher or the like. In this specific embodiment, the longitudinal axis  106  of the feeding tube  101  and the passage  111  coincide. In other embodiments the longitudinal axis of the feeding tube and the passage may not coincide, or even have a different orientation. A consequence of the longitudinal axis  106  of the feeding tube  101  and the passage  111  coinciding in this specific embodiment is that the conveying direction  109  is oriented along the longitudinal axis  106 . In some other embodiments the orientation of the conveying direction with respect to the longitudinal axis of the feeding tube may change along the passage. With relation to the invention, the passage cross section is measured in a plane perpendicular to the conveying direction  109 . The passage cross section can be changed by adjusting an adjustable inner wall portion  118 . When the adjustable inner wall portion  118  is adjusted, the distance between the adjustable inner wall portion  118  and an opposite wall portion  110  is changed. The passage cross section is related to the passage diameter. As the invention is applicable to feeding tubes having all kinds of passage cross sections, like circular, elliptical, the overlap of two circles having a different radius, or any other suitable form known in the art, it is noted, in order to prevent confusing when using the term diameter, that when reference is made to a diameter of a cross section, the largest possible length of a straight line through the center of the relevant object from side to side is implied. The distance between the adjustable inner wall portion  118  and the opposite inner wall portion  110  can coincide with this diameter. 
         [0052]    Near the inlet opening  107 , the passage cross section is A 1 . The feeding tube  101  further comprises an adjustable inner wall portion  118 , being a slideable body  113  in this embodiment, which can be adjusted by moving handle  114  into or against the direction of arrow  115 . On movement of the handle  114 , the slideable body  113  will slide in or out of the passage  111 , depending on the direction of movement applied to handle  114 . When moving the handle  114  into the direction of arrow  115 , the feeding tube passage diameter changes. In this figure, the adjustable inner wall portion  118  has been adjusted to have the passage cross section reduced to A 2  by adjusting the adjustable inner wall portion  118  such that the distance between the adjustable inner wall portion  118  and the opposite wall portion  110  is d 2 . A 2  is relatively small when compared to A 1 , thereby the adjustable inner wall portion  118  has adjusted the feeding tube passage  111  to small diameter food articles, like e.g. carrots, leek, asparagus, or the like. The adjustable inner wall portion  118  has a profile  116 . In this specific embodiment the profile  116  is such that the profile increases seen in a direction of the along the longitudinal axis  106  of the feeding tube  101 , from the first end  109  to the second end  110 . In this embodiment, the profile is substantially of an S-shape. Other profile shapes are possible as well, such as a ramp or a curved sloping line. 
         [0053]      FIG. 1B , shows the embodiment of  FIG. 1A  wherein the adjustable inner wall portion  118  is adjusted to accommodate large cross section food articles, like e.g. apples, pears, potatoes, beetroot or onions, to pass through the passage  111 . To realize this, the slideable body  113  was slid outward by moving the handle  114  into the direction of arrow  117 . In this  FIG. 1B , the position of the slideable body  113  creates a cross section A 3 , related to the distance between the adjustable inner wall portion  118  and the opposite wall portion  110  being d 3 . As the slideable body  113  is slid to its maximal outer position, diameter A 3  is substantially equal to diameter A 1 , thus allowing food articles to pass the passage having a large diameter. 
         [0054]    The slidable body  113  can be can be made of any hard materials, especially metals (e.g. aluminum, copper, stainless steel, or the like), or hard plastics. To improve the cleanability of the slidable body  113 , it can be coated with a smooth material, for example polytetrafluoroethylene (PTFE), a nano-coating or a sol-gel material. 
         [0055]      FIGS. 2A ,  2 B and  2 C further illustrate the notion of the minimum cross section by showing a schematic cut through of the embodiment shown in Figures IA and  1 B.  FIG. 2C  corresponds with the embodiment shown in figure IA cut along the line indicated I, looking towards the inlet opening  107 . A food article (not shown) can pass the feeding tube  101  when it has a cross section smaller or equal than the minimum cross section A 2 . When the food article cross section is substantially equal to the minimal cross section A 2  of the food article, the food article will be fixated with respect to the longitudinal axis  106  of the feeding tube  101 . Consequently, no or little play is present, preventing the food article from violent behavior in the passage  111  of the feeding tube  101  during processing. While also referring to  FIGS. 1A and 1B , the processing of the food article in a food processor  102  typically involves high-speed rotating food processing tools  104 . Such tools, for example a slicing knife or a grating disc, exert forces on the food article being processed. When the food article has little play, these forces cannot lead to bouncing or the like. This can lead to good food processing results, i.e. regularly cut slices, e.g. to make a well presented salad. Also, little play prevents noise being produced by violent behavior of the food article, e.g. when bouncing. This is especially the case when hard food articles are to be processed. 
         [0056]      FIG. 2A  corresponds with the embodiment shown in  FIG. 1B  cut along the line indicated II, looking towards the inlet opening  107 . The minimum cross section A 3  is substantially equal to the cross section A 1  of the inlet opening  107  (visible in  FIG. 1B ). 
         [0057]      FIG. 2B  shows a third position of the slideable body  113  of the adjustable inner wall portion  118 . This position of the slideable body results in the minimum cross section being adjusted to A 4 . 
         [0058]    In  FIGS. 2A ,  2 B and  2 C, d 3 , d 4  and d 2  indicate the distances between the adjustable inner wall portion  118  and the opposite wall portion  110  corresponding to respective passage cross sections shown. 
         [0059]    An embodiment of the feeding tube of the invention having a deformable body is depicted in  FIGS. 3A and 3B . In this embodiment the feeding tube  201  having a passage  211  comprises a first part  220  and a second part  221  which are mutably movable along the directions of arrows  223  and  224 . A deformable body  222  is provided on an inner side  212  of feeding tube  201 . The deformable body  222  might comprise a bag filled with some fluid, such as water, oil, gel or the like, or can be made of one piece of resilient material like rubber or some plastic. The feeding tube  201  is shown as being cut in a plane containing the feeding tube&#39;s longitudinal axis  206 . Any orientation of this plane would have resulted in a similar cut through as the feeding tube  201  is substantially rotational symmetric. During use, the user will introduce a food article (not shown) in the feeding tube inlet opening  207 . The food article will travel through passage  211  towards the outlet opening  208 . By changing the relative position of parts  220  and  221  the passage cross section can be adjusted. This movement can be a straight up-down movement as shown in this embodiment. In other embodiments this can for example be a screw movement. In such a screw movement configuration the first part  220  and second part  221  typically have a screw thread and cooperation screw groove. Screw configurations are known per se and not further detailed here. 
         [0060]      FIG. 3A  shows the feeding tube  201  being adjusted to have a maximal passage cross section, implying a maximal distance d 6  between the adjustable wall portion  225  and the inner wall portion  226  opposite the adjustable wall portion  225 . This can be seen from the passage  211  having a cross section A 6  equal to the inlet opening cross section A 5 . The person skilled in the art will appreciate that when cross section A 6  is larger than cross section A 5 , the same effect will be reached, that is the effect that the passage cross section is maximized. A maximized passage cross section as shown in  FIG. 3A  is especially suited when large food articles have to be processed. To accommodate efficient and effective processing of thin food articles the first part  220  and the second part  221  can be moved with respect to each other in the direction of arrow  224  or arrow  223  respectively. An example of a resulting feeding tube is according to this embodiment is shown in  FIG. 3B . The passage cross section has been narrowed down to A 7 .This implies that the distance between the adjustable wall portion  225  and the inner wall portion  226  opposite the adjustable wall portion has been reduced compared to  FIG. 3A . In  FIG. 3B  this distance is denoted as d 7 . Consequently, only smaller food articles can be fed through passage  211 .  FIG. 3B  also illustrates another important feature of the feeding tube according to this embodiment, namely that the feeding tube height is related to the passage cross section. A large height, such as h 1  in  FIG. 3A  is related to a large passage cross section, a small height, such as h 2  is related to a small passage cross section. In many regions safety regulations are in place with respect to the relation between feeding tube height and feeding tube passage cross section. The embodiment of the feeding tube according to the invention shown in  FIGS. 3A and 3B  has the additional benefit that at least in some jurisdictions the relation between the feeding tube height and the minimal passage cross section is in compliance with the safety regulations for all heights of the feeding tube, given that the deformable body volume has a certain minimum value. This minimum value is dependent on the precise configuration of the feeding tube and not part of this invention. Furthermore, an additional advantage of this embodiment of the feeding tube according to the invention is that the feeding tube height can be reduced when storing the feeding tube. A feeding tube with reduced height needs less volume in a kitchen closet or other storage space, allowing for easier storage. 
         [0061]    Another embodiment of the feeding tube of the invention having a deformable body is depicted in  FIGS. 4A and 4B . In this embodiment the feeding tube  301  having a passage  311  comprises a first part  320  and a second part  321  which are mutably movable along the directions of arrows  323  and  324 . A deformable body  322  is provided on an inner side  312  of feeding tube  301 . This deformable body  322  is an adjustable inner wall portion  318 . In this embodiment the deformable body  322  can be made of e.g. a thin, pliable sheet of material like metal, rubber, plastic or the like. The operation of this embodiment is more or less similar to that of the embodiment shown in  FIGS. 3A and 3B  and will not be detailed further. In addition, a detent  325  is present on the inner side  312  of the first part  320  of the feeding tube  301  for cooperation with notch  326  being present on the outside  327  of second part  321  of feeding tube  301 . When the first part  320  is moved in the direction of arrow  324  the minimal cross section of passage  311  is decreased while the deformable body  322  is compressed in the direction of the longitudinal axis  306  of the feeding tube  301 . In effect, the adjustable inner wall portion  329  will move closer to its opposite inner wall portion  328 , thereby reducing the distance between these two wall portions. Due to being compressed, the deformable body will generate a force having a component in the direction of arrow  323 . To relieve the user from the effort of holding the first part  320  and the second part  321  in a desired relative position, detent  325  and notch  326  are provided. Detent  325  can releasably connect with notch  326 . Such a connection is shown in  FIG. 4B . Releasable detent and notch structures are known from the art and not detailed any further.  FIG. 4A  shows one notch  326  only. In other embodiment a plurality of holes can be provided to cooperate with one or more bolts. 
         [0062]      FIGS. 5A and 5B  show an embodiment of the feeding tube of the invention having an inflatable body. Feeding tube  401  has an inlet opening  407  and an outlet opening  408 . A passage  411  is connecting the inlet opening  407  and the outlet opening  408 . On the inner side  412  of the feeding tube  401  an inflatable body  440  acting as an adjustable inner wall portion  418  is arranged which can be inflated using air valve  441 . For supplying air to the air valve  441  an air pump  443  is provided, which is connected to the air valve  441  by tube  444 . The operation of the air pump  443  is controlled by the control unit  442 . The control unit  442  receives input from a measurement unit  446  through communication line  447 . In other embodiments this communication can be e.g. wireless. Measurement unit  446  measures a size of a food article (not shown). The control unit  442  controls the actuator, in this embodiment air pump  443  to actuate the adjustable inner wall portion  418 . The air pump  443 , for example based on an electric motor driving a fan (both not shown), than actuates through an actuator unit  443 A the adjustable inner wall portion  418  to obtain the required minimal cross section A 8 , A 9  of the passage  411  wherein the distance between the adjustable inner wall portion  418  and an inner wall portion  450  opposite the adjustable wall portion  418  is d 8 , d 9  respectively. Input means can for example be formed by one or more switches, sliders or the like. Other types of suitable, widely known input means can be applied as well. 
         [0063]    In another embodiment, somewhat resembling the embodiment of  FIGS. 5A and 5B , not having a measurement unit  446  being connected to the control unit  442 , the control unit  442  can have input means shown, allowing the user to input the required minimal cross section A 8  or A 9 . Input means can for example be formed by switches, slider or the like. Other types of suitable, widely known input means can be applied as well. In yet another embodiment a measurement unit  446  can be present as well as a control unit  442  allowing the user to input a desired minimum cross section  411 , e.g. by overriding the setting resulting from the measurement made by the measurement unit  416 . 
         [0064]    In this embodiment the inflatable body  440  can be inflated by varying the amount of air inside the inflatable body  440 . In other embodiments, it is feasible to use another fluid medium, either gaseous or liquid, for example helium or water. 
         [0065]      FIG. 5A  shows the inflatable body  440  to be inflated such that it allows a passage cross section A 8 . Following inflation by forcing air into valve  441 , the volume of the inflatable body increases, leading to a smaller passage cross section A 9  as shown in  FIG. 5B . When air is allowed to escape through  441 , the volume of the inflatable body can be reduced, and thereby the passage cross section enlarged. 
         [0066]      FIGS. 6A and 6B  show a cut through of the feeding tube of the invention according the embodiment shown in  FIGS. 5A and 5B  respectively, whereby the cut through is done in a direction perpendicular to the feeding tube  401  longitudinal axis  406 . Due to the orientation of the cut of  FIGS. 6A and 6B , the passage cross sections shown are perpendicular to the feeding tube&#39;s longitudinal axis  406 . The passage cross section is bounded by the inner side  442  of the inflatable body. 
         [0067]      FIG. 7  shows a food processor  702  having a feeding tube  701  for feeding food articles to be processed (not shown) to the food processing tool (not shown) located in the housing  703  of the food processor  702 . On the outside of the housing  703  a control unit  750  is provided. Food processors having a control unit for the control of the operation of food processors, e.g. to start or stop the food processor  702 , to control the speed of the food processing tool, to provide a timer for the duration of the food processing tool operation, et cetera, are widely known and not part of the invention. In this embodiment, the control unit  750  allows the user to control the adjustment of an adjustable inner wall portion being an integral part of a feeding tube according to the invention. The feeding tube  701  has an inflatable adjustable inner wall portion (not shown). Such an inflatable adjustable inner wall portion is described in more detail in the discussion of the embodiments shown in  FIGS. 5A ,  5 B,  6 A and  6 B. An electric air pump  751  is attached to the feeding tube  701 . Air pump  751  is connected to air valve  753  of the inflatable adjustable inner wall portion by tube  752  through an actuator unit  751 A. Further, the air pump  751  is connected to the control unit  750  by an electric wire  754  (shown dashed as this wire  754  is not visible from the outside of the food processor  702  and feeding tube  701 ). During operation a user can adjust the minimum cross section of a passage  711  of the feeding tube  701  by pushing buttons  755  and/or  756 . When the user desires to increase the cross section of passage  711  he or she will push button  755  which causes the control unit  750  to send a control signal through wire  754  to the air pump  751  indicating to the air pump  751  to decrease the amount of air in the inflatable adjustable inner wall portion, thereby increasing the cross section of passage  711 . If the user on the contrary desires to decrease the cross section of passage  711  he or she will push button  756  which, in a manner similar as described above, will result in a control signal being send to air pump  751  causing the air pump  751  to increase the amount of air in the inflatable adjustable inner wall portion of feeding tube  701 . 
         [0068]    While the invention has been illustrated and described in detail in the drawings and in the foregoing description, the illustrations and the description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. It is noted that the feeding tube as well as the food processor according to the invention and their components can be made by applying processes and materials known per se. In the set of claims and the description the word “comprising” does not exclude other elements and the indefinite article “a” or “an” does not exclude a plurality. Any reference signs in the claims should not be construed as limiting the scope. It is further noted that all possible combinations of features as defined in the set of claims are part of the invention.