Abstract:
An appliance includes a housing ( 1 ) containing a motor ( 2 ) whose output shaft ( 8 ) passes through the housing base ( 4 ) and drives in rotation a tool ( 16 ) housed in a bowl ( 9 ) locked on the housing and closed by a lid ( 12 ); and a safety device ( 25 ) having a vertical thruster ( 27 ) mounted sliding in the bowl ( 9 ) peripheral wall ( 30 ) and actuated by a cam ( 43 ) borne by the lid ( 12 ) so as to penetrate in an opening ( 39 ) provided in the base to be urged to actuate a switch controlling the motor. A rigid cover ( 49 ) is mounted on the base movable between an inoperative position wherein it conceals the base opening ( 39 ), when the bowl is not on the base ( 4 ), and an operative position wherein it clears the opening ( 39 ) by the action of an actuating member ( 51 ) borne by the bowl ( 9 ) when the latter is locked on the base ( 4 ).

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This is the 35 USC 371 national stage of International Application PCT/FR98/01426 filed on Jul. 3, 1998, which designated the United States of America. 
     FIELD OF THE INVENTION 
     The present invention relates to an electric household appliance for the processing of foods, of the type particularly, but not exclusively, of the food processor type, which comprises a housing enclosing an electric motor group and having a region forming a base whose upper surface is traversed by the output shaft of the motor group, and a bowl removably locked on the base of the housing, closed to lock with a removable cover, and receiving a working tool adapted to be driven in rotation by the motor shaft. 
     It relates more particularly to an apparatus of this type which moreover comprises a safety device comprising a switch arranged in the supply circuit of the motor, a pusher mounted vertically slidably in a recess provided over all the height of the peripheral wall of the bowl, whose lower end is disposed in alignment with an opening provided in the periphery of the base of the housing, when the bowl is locked on the base, and whose upper end is adapted to be actuated by a cam carried by the cover, when this latter is locked on the bowl in place, such that the pusher is lowered into the opening in the base, as well as a control mechanism disposed in the housing, actuated by the pusher when it is pushed down into said opening, and controlling the opening of the switch to permit controlling the closure of the switch to permit supply of the motor. 
     BACKGROUND OF THE INVENTION 
     It is known that in such apparatus, it is important to avoid any contact of the hand with the rotating working tool, constituted generally by a slicing tool considered dangerous, so as to prevent accidents and, to this end, the safety device of the above type with which the apparatus is provided is adapted to permit the operation of the motor only when the bowl is locked on the base of the housing, and when this bowl is itself locked by the cover. 
     In an electrical household appliance provided with a known safety device of this type, as described in FR-A-2 472 925, the opening of the base adapted to the passage of the pusher opens outwardly when the bowl is not in place on the base, and is closed in its lower portion by a flexible deformable membrane which is maintained by a lip formed on the internal surface of the base, such that during locking of the cover on the bowl once in place on the base, the cam carried by the cover actuates the pusher which is then pushed down into the opening of the base, which pusher stretches the membrane and acts on the control mechanism of the switch to cause closing of the electrical supply circuit of the motor. However, this flexible membrane itself constitutes a costly member, difficult to emplace, adapted to come off, and subject to deterioration with time, even to be torn by the repeated stretching under the action of the pusher, thus rendering the apparatus unusable. Moreover, the opening of the base being outward, and hence visible, when the bowl is not in place, the latter tends to attract the attention, in particular of a child, and thus lead to accidental starting of the motor by stretching of the membrane with any object introduced into this opening. Moreover, this opening in the base forms a food trap which is therefore apt to frustrate the control of the switch, and which is difficult to clean. 
     SUMMARY OF THE INVENTION 
     The invention particularly has for its object to overcome these drawbacks and to provide an electrical household appliance, of the type described above, in which the safety device operates perfectly and with high reliability. 
     According to the invention, the safety device comprises moreover a rigid piece forming a cover which is movably mounted on the upper surface of the base of the housing between a rest position to which it is automatically brought when the bowl is not in place on the base and in which it masks the opening of the base, and an active position in which it is moved under the action of an actuating member carried by the bowl upon locking the latter on the base and in which it uncovers the opening of the base so as to permit passage of the pusher. 
     Thus, this rigid cover constitutes thereafter a truly robust mechanical piece, and hence is reliable, simpler, lost costly, easy to make and perfectly adapted to mass production. Moreover, the opening in the base being masked automatically by the cover in the rest position, when the bowl is not in place, this cover constitutes itself a member adapted to dissuade any child from having access to the control mechanism of the switch, and hence accidentally to start the motor, which especially increases the safety of the device. This increase in safety is the more justified as the movement of the cover permits uncovering the opening of the base which is itself subjected to the locking of the bowl on the base. 
     According to a preferred embodiment, the cover is horizontally slidably mounted, in a direction transverse to the vertical axis of the motor shaft, in a recess which is provided in the upper surface of the base extending to the peripheral edge of said base, and into which opens the opening of the base, said cover being slidably mounted the action of a return spring which tends to return it to the rest position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The characteristics and advantages of the invention will become more apparent from the description which follows, by way of non-limiting example, with reference to the accompanying drawings, in which: 
     FIG. 1 is a schematic exploded view in vertical cross-section of a housing, of a bowl and of a cover of an electrical household appliance according to the invention; 
     FIG. 2 is a view similar to FIG. 1, after locking the bowl on the housing; 
     FIG. 3 is a view similar to FIG. 2, after locking the cover on the bowl; 
     FIG. 4 is a schematic perspective view, on an enlarged scale, of a cover on which is pivotally mounted a swinging lever; 
     FIG. 5 is a schematic perspective view, on a larger scale, of this swinging lever; and 
     FIGS. 6,  7  and  8  are schematic plan views of a sliding control member for two switches, associated with the cover of FIG. 4, and adapted to occupy three positions corresponding respectively to a rest position (FIG. 6) in which the bow is not locked on the base (FIG.  1 ), an intermediate position (FIG. 7) in which the bowl is locked on the housing (FIG.  2 ), and a closure position (FIG. 8) in which the cover is locked on the bowl in place (FIG.  3 ). 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The electric household appliance for food processing, shown in FIGS. 1 to  3 , is a food processor comprising a housing or a base  1  having a general L shape which encloses an electric motor group  2  and which has a region forming a base  4 , for example of circular shape, whose upper surface  6  is traversed by the vertical output shaft  8 , along an axis XX′, of the motor group. On this base  4  is adapted to be mounted removably a working bowl or receptacle  9  made of transparent plastic material and provided with a handle  10 . The bowl  9  is adapted to be closed by the removable cover  12  provided with a hopper or feed tube  13  into which are introduced the foodstuffs to be prepared. 
     The bowl  9  has a bottom wall  14  surmounted by a chimney  15  (FIG. 1) in which the output shaft  8  of the motor group  2  is engaged, and houses a rotating working tool  16 , such as a knife, which is fitted on the chimney  15  and which is coupled in rotation with the output shaft  8  of the motor group  2 . 
     The bowl  9  is locked on the base  4  by means of a bayonet securement system and, to this end, the upper surface  6  of the base  4  has a projecting disk  18  whose upper surface  19  is provided laterally, regularly about its periphery, with a plurality of notches  21 , better seen in FIG. 1, in which are inserted, upon rotation of the bowl  9 , lugs  22 , better seen in FIG. 1, carried by the external surface of the bottom wall  14  of the bowl  9 . 
     The cover  12  is locked on the bowl  9  by means of a securement system of the bayonet type, of which one of the elements is designated  23  in FIGS. 1 and 2. 
     The food processor, FIGS. 1 to  3 , moreover comprises a safety device, designated by the overall reference numeral  25  in FIGS. 1 and 3, comprising a pusher  27  mounted vertically slidably in a recess  29  provided over all the height of the peripheral wall  30  of the bowl  9  located facing the handle  10  of the bowl. The pusher  27  is slidably mounted against the force of a return spring  32  interposed between the horizontal bearing surface  33  formed in the peripheral wall  30  of the bowl and a small horizontal wing  34  formed at right angles on the pusher  27 , in the lower part of this latter, see FIG.  1 . 
     This pusher  27  has a lower end  36  which projects slightly through an opening  37  provided in the bottom of the peripheral wall  30  of the bowl  9 , as shown in FIG. 1, and which is disposed in line with an opening  39  (FIGS. 2 and 3) provided in the periphery of the base  4 , when the bowl  9  is locked to the base  4  as shown in FIG.  2 . 
     The pusher  27  also has an upper end  41  which is actuated by a cam  43  carried by the cover  12 , when this latter is locked on the bowl  9  in place as shown in FIG. 3, such that the pusher  27  is received within the opening  39  of the base against its return spring  32 , see FIG.  3 . 
     The safety device  25 , FIG. 3, also comprises a control mechanism  45 , which will be described in detail later, disposed in the housing  1 , actuated by the pusher  27  when it is received in the opening  39  (see FIG. 3) and controlling the closing of a first switch, designated  47  in FIGS. 6 to  8 , arranged in the supply circuit of the motor group. 
     According to the invention, this safety device moreover comprises a rigid member forming a cover  49  which is movably mounted on the upper surface  6  of the base  4  between a rest position (FIG. 1) to which it is automatically brought when the bowl  9  is not in place on the base  4  and in which it masks the opening  39  in the base, and an active position (FIG. 2) to which it is moved under the action of an actuating member  51  carried by the bowl  9  during locking of this latter on the base  4  and in which it uncovers the opening  39  in the base so as to permit the passage of the pusher  27 . 
     According to a preferred embodiment of the invention, shown in FIGS. 1 to  3 , the cover  49  is in the general shape of a rectangular plate which is slidably horizontally mounted, in a direction orthogonal to the vertical axis XX′ of the output shaft  8  of the motor group  2 , in a recess  53  which is provided in the upper surface  6  of the base  4  extending to the peripheral edge of this base, and into which opens the opening  39  in the base. This cover  49  is slidably mounted against the action of a return spring  55  connected to the control mechanism  45  and adapted to return it to the rest position (FIG.  1 ). 
     In this embodiment, the base  4  has at its periphery, on the same side as the cover  49 , an integral vertically projecting bulge  57  having an upper portion forming a wing  58 , for example of substantially semicircular shape as shown in broken lines on FIGS. 6 to  8 , which raises it to a certain height relative to the upper surface  6  of the base  4 . In this embodiment, the cover  49  comprises itself, at its front end located at the periphery of the base  4 , a vertical wing  61 , of a shape identical to that of the wing  58 , in this instance of substantially semicircular shape but inverted relative to the shape of the wing  58  as is seen in FIGS. 4 and 6 through  8 , which raises it to the same height as this wing  58  relative to the upper surface  6  of the base  4 . Thus, when the cover  49  is in the rest position (FIG.  1 ), the two wings  58  and  61  are laterally secured to each other by their flat surface, thereby providing a seal for the housing  1 ; when the cover  49  slidably occupies, after a short movement, of the order of 3 millimeters, its active position (FIG.  2 ), the wing  61  of the cover  49  is then separated from the wing  58  of the bulge  57  so as to form between them a space  63  opening into the recess  53  of the cover and constituting itself the passage opening for the pusher  27 . 
     As shown in FIG. 1, one of the notches  21  of the disk  18  extends to the level of the cover  49  and has an opening  64  through the disk, whilst the member  51 , adapted to actuate the cover  49  upon rocking of the bowl  9  on the base  4 , is in the form of a ramp provided on one of the lugs  22  of the bowl which is associated with this notch  21 . The cover  49  carries a transverse rib  65  which is positioned in the opening  64  of this notch  21  in a manner subjacent to the upper surface of the disk  18 , when the bowl  9  is not in place on the base  4 , see FIG.  1 . During locking by rotation of the bowl  9  on the base  4 , the ramp  51  of the lug  22  of the bowl acts on the rib  65  of the cover  49  thereby to effect sliding of the cover  49  toward the center of the base  4 , whose wing  61  separates from the wing  58  of the bulge  57  to form the opening  63  for passage of the pusher  27 , as shown in FIG.  2 . 
     Preferably, the cover  49  as well as its wing  61  and its rib  65  are molded of a single piece of rigid plastic material, as for example polypropylene. 
     It will here be noted that, when the bowl  9  is not in place on the base  4  (FIG.  1 ), the passage opening for the pusher  27  is closed by contact of the two wings  58  and  61 , and the rib  65  of the cover is hidden below one of the lugs  21  of the disk  18 , such that the cover  49  effectively prevents any child from manipulating this cover to make it slide in a way that could accidentally start the motor, thereby increasing the safety of the apparatus. 
     The control mechanism  45 , FIGS. 1 to  3 , comprises a swinging lever  68  extending below the cover  49 , of which one end  69  is located adjacent the peripheral edge of the base  4  and is adapted to be actuated by the pusher  27  when the latter enters the opening  63  (FIG.  3 ), and whose other end  70  is shaped as a small lever  72 , better seen in FIG. 5, which is articulatedly mounted on the upper surface of the cover  49 , as seen in FIG. 4, through a recess  74  provided in the cover, by means of two pivots  76  constituting the swinging axis of the lever  68 . This small lever  72  is urged by an energy storage compression spring  78  which, before swinging of the lever  68 , extends in a plane parallel to the latter passing through the return spring  55  of the cover  49 , as shown in FIG.  1 . 
     This control mechanism  45  moreover comprises a control member  81 , better seen in FIGS. 6 to  8 , which is traversed by the output shaft  8  of the motor group, and which is horizontally slidably mounted in the housing  1 , in the same direction as the cover  49 . This control member  81  is associated with a vertical tongue  83  carried by the lever  68 , below the small lever  72 , and is urged by the return spring  55 . 
     As seen in FIGS. 6 to  8 , the control member  81  has at its rear portion two horizontal fingers  85  and  86 , parallel to each other and extending perpendicularly to the direction of sliding of the control member  81 , as indicated by the arrow F in FIGS. 6 and 7. The finger  85  is adapted to coact with pushbutton  87  for the switch  47  for controlling the closing of the supply circuit of the motor group, whilst the finger  86  is adapted to coact simultaneously to the finger  85  with a pushbutton  89  of a second switch  90 , mounted reversely, and connected electrically to a device (not shown) but known per se, to control the braking of the electric motor. 
     By way of example, this braking device can be designed to cause to flow in the electric motor, if the latter is of the universal type, a countercurrent which creates a magnetic field tending to cause the motor to rotate reversely. 
     Preferably, the control member  81  and the two actuating fingers  85  and  86  are molded of a single piece of plastic material. 
     When the bowl  9  is not in place on the base  4 , as shown in FIG. 1, the cover  49  is in rest position in which the passage opening for the pusher  27  is completely closed by the lateral contact of the two wings  56  and  61 , and the control member  81  also occupies a rest position, shown in FIG. 6, in which the two fingers  85  and  86  do not actuate the two switches  47  and  90 , respectively. 
     During locking by rotation of the bowl  9  on the base  4 , FIG. 2, the cover  49  slides to expose the opening  63  into which penetrates the lower end  36  of the pusher  27 ; in the course of this sliding of the cover  49 , the tongue  83  of the lever  68  articulatedly mounted on the cover  49  causes the sliding of the control member  81  against the return spring  55 , in a first portion of the path of said approach, designated d in FIG. 6, at the end of which the two fingers  85  and  86  come into contact with the respective pushbuttons  87  and  89  of the two switches  47  and  90 , as shown in FIG.  7 . 
     Then, in the course of locking by rotation the cover  12  on the bowl  9 , as shown in FIG. 3, the pusher  27  enters the opening  63  under the action of the cam  43  carried by the cover  12  and acts by its lower end  36  on the end  69  of the lever  68  which thus swings in a clockwise direction about the pivots  76  of the small lever  72 . During swinging of the lever  68 , the tongue  83  which carries this latter causes a new sliding of the control member  81 , again against the return spring  55 , on a second portion of the path, designated d′ in FIG. 7, at the end of which the two fingers  85  and  86  depress the respective pushbuttons  87  and  89  of the two switches  47  and  90 , as shown in FIG.  8 . The switch  47  is then closed so as to permit a supply of the motor group  2 , whilst the switch  90  remains in an open position. 
     It should be emphasized here that the energy storage compression spring  78  has a compressive force which is substantially greater than that of the return spring  55 , so as to maintain pushed in the two respective pushbuttons  87  and  89  of the two switches  47  and  90  at the end of the path (d+d′) of said control member  81 . 
     After processing the food, the user unlocks the cover  12  in the course of which the cam  43  which it carries frees the pusher  27 , which then rises under the action of its return spring  32  and which gives rise to a swinging in the counterclockwise direction of the lever  68 ; the assembly formed by the control member  81  and the cover  49  then slides in the reverse direction under the action of the return spring  55 , along the portion of the path d′ (FIG. 7) at the end of which the two fingers  85  and  86  free the respective pushbuttons  87  and  89  of the two switches  47  and  90 , as shown in FIG.  7 . The switch  47  opens, whilst the switch  90  passes from the closed condition in which it controls the braking device of the motor group  2 , so as to stop very rapidly the rotation of the tool  16 , and this even before the cover is completely withdrawn, thereby preventing any possibility of injury to the user. 
     The user then proceeds to unlock the bowl  9 , then upon its withdrawal in the course of which the control member  81  and the cover  49  again slide in the reverse direction, along this time the portion of the path d (FIG.  6 ), to return to their rest position, as illustrated in FIGS. 1 and 6, in which the cover  49  closes the opening of the passage for the pusher  27 . 
     It will be noted that the above description has been given with reference to a safety device for a food processor. Of course, this safety device is equally applicable to any other electrical household appliance for processing foods, such as in particular an electric chopper with a rotating knife, so designed that the housing enclosing the motor group will be arranged below the working bowl.