Patent Publication Number: US-7712323-B2

Title: Device for producing ice cubes in a refrigerator

Description:
This invention relates to a device for producing ice cubes in a refrigerator. 
   More specifically, the object of the invention is a device for producing of ice cubes, of the type comprising
         a basin-like container in which partitioning baffles define a plurality of cavities or moulds open at the top, intended to hold a respective quantity of water put into them by means of a feed solenoid valve for the formation of corresponding ice cubes;   an ejection device, that includes an electric motor borne on a support structure, and to which a shaft is coupled rotatably with respect to the container, from which stretch a plurality of ejector elements capable of extending into said cavities or moulds and provoking the expulsion of the ice cubes formed in said cavities or moulds as an effect of the rotation of said shaft; and   means of control associated with the motor and with said water feed solenoid valve, and comprising a rotating element, operatively driven in rotation by the motor at a predetermined speed and cooperating with associated electric switching means in such a way as to define a predetermined operating cycle including at least one time interval of predetermined duration for the opening of said water feed solenoid valve.       

   Devices of this type are known, in which the means of control comprise a rotating disc bearing a plurality of electrically conducting tracks, operatively sliding against associated stationary electric contacts for the sequential activation of the various devices and components. 
   In these known devices, the duration of the time interval for opening the water feed solenoid valve is defined by the angular extension of one of these conducting tracks borne by the rotatable disc. 
   To obtain a fairly precise setting of the duration of the opening time interval of the water feed solenoid valve, at least one end of this conducting track is cut in a non-radial direction, and the position of the associated stationary electric contact intended to explore this track is radially adjustable, in an absolutely manual manner, by means of a screw device. 
   The known devices are therefore structurally complex and require a setting operation at the end of the production line. 
   The purpose of this invention is to overcome the problems outlined above in devices according to the prior art. 
   This and other purposes are realized according to the invention with a device of the type defined initially, characterized by the fact that the above-mentioned means of control comprise
         a first and second cam element, coaxial and adjacent to one another, mounted rotatably with respect to the abovementioned support structure and coupled to the motor in such a way that they rotate in operation at a first and, respectively, at a second speed, of which the second is higher than the first;   a feeler element which engages the profiles of said cam elements and is oscillatable around an axis essentially parallel to their axis of rotation, and cooperates with an associated electric switch controlling the opening of said water feed solenoid valve;   the first and second cam elements having at least one enabling profile and, respectively, a control profile the conformation of which is suitable for allowing the feeler to tend to place itself in a position in which it controls the opening of the water feed solenoid valve; the speed of the cam elements and the angular extensions of their respectively enabling and control profiles being such that with every revolution of the first cam element the control profile of the second is engaged by the feeler at least once in a time interval falling within the time interval in which the feeler engages the enabling profile of the first cam element;   the arrangement being such that the feeler is capable of assuming the abovementioned position of control of the opening of the water feed solenoid valve when it simultaneously engages the enabling and control profiles of the first and second cam element.       

   In the devices according to the invention it is not therefore necessary to carry out any adjustment operation at the end of the production line. 

   
     Further characteristics and advantages of the invention will appear from the detailed description which follows, which is purely exemplificative and not limitative, with reference to the attached drawings, in which: 
       FIG. 1  is a perspective view, partly exploded, of a device according to the invention; 
       FIG. 2  is a partial perspective view showing part of the device according to  FIG. 1 ; 
       FIG. 3  is an exploded perspective view of the part of the device illustrated in  FIG. 2 ; 
       FIG. 4  is a partly exploded view of a sub-assembly of the device according to the previous figures; and 
       FIG. 5  is a partial perspective view, partly sectioned, and on an enlarged scale, of part of the device according to the previous figures. 
   

   In  FIG. 1 ,  1  indicates the entire device according to the invention for the production of ice cubes in a refrigerator (not illustrated). 
   The device  1  comprises a basin-like container  2  with an elongated form, in which a plurality of parallel partitioning baffles  3  defines a corresponding plurality of cavities or moulds  4 , open at the top. 
   In a manner known per Se, the cavities or moulds  4  of the container  2  are intended to contain a respective quantity of water supplied by means of a solenoid valve of the on-off type for the formation of corresponding ice cubes. 
   In a manner known per se and not represented, an electric resistance heater device is also associated with the container  2 . 
   The container  2  can be realized, for example, with a metal material, such as an aluminium-based alloy, and the electric heater device can conveniently be a resistance heater arranged in a heat exchange relationship along the external surface of the container  2 . 
   Alternatively, the container  2  can be realized with a plastic material. 
   The electric heater device can be realized with a layer of electrically resistive ink, deposited by means of a printing process, screen-printing for example, on the surface (preferably the internal one) of the container  2 . 
   In any case, this electric heater device is intended, when activated, to provoke the detachment of the ice cubes from the wall of the respective cavities or moulds  4 , with a view to their subsequent expulsion. 
   The device  1  can also comprise an electric temperature sensor associated with the container  2 . This sensor, which is not visible in the drawings, can for example be a resistive filament resistor with a negative temperature coefficient (NTC). 
   Associated with the container  2  is an ejection device indicated overall by  5  in  FIG. 1 . 
   This device comprises a shaft  6 , supported in a rotatable manner with respect to the container  2 . Extending from the shaft  6  is a plurality of ejector elements  7 , protruding transversally, capable of extending themselves into the cavities or moulds  4  in the container  2  and provoking the expulsion of the ice cubes formed in them as an effect of the rotation of the shaft  6 . 
   The ejection device  5  also comprises a motor device, indicated overall by  8 . This device includes an electric motor  9 , of the type known per se, for example a synchronous alternating current electric motor, coupled with the shaft  6  by means of a gear speed transmission indicated overall by  10 . 
   With reference in particular to  FIGS. 1-3  and  5 , the motor device  8  is borne by a support structure  11  (see  FIG. 3  in particular), for example of a moulded plastic material. In particular, the electric motor  9  is coupled to a gear speed reducer  12  which has a toothed output wheel  13  coaxial and integral with a toothed sprocket  14  with a smaller diameter. The assembly formed by the electric motor  9  and by the associated speed reducer  12  is fixed to the support structure  11  by means of screws  15  ( FIGS. 3 and 4 ), with the interposition of a printed circuit board  16 , provided with a plurality of openings, one of which (indicated by  17  in  FIG. 3 ) is penetrated by the toothed sprocket  14 . This sprocket also extends through a corresponding opening  18  of the support structure  11 , beyond which it engages with a toothed wheel  19  with an increased diameter ( FIGS. 3 and 5 ). 
   The toothed wheel  19  has a hub  20  ( FIG. 3 ) supported in rotation in an integral bushing  21  of the support structure  11 . This hub extends through an opening  22  of the printed circuit board  16  ( FIG. 3 ) and is torsionally coupled with an axial tang  23  ( FIGS. 3 and 4 ) of a driving element  24  which, as can be understood by observing  FIG. 1 , is coupled rotatably with one end  6   a  of the shaft  6 . 
   As can be seen in particular in  FIGS. 4 and 5 , the driving element  24  has an intermediate formation  25 , essentially disc-like, with an increased diameter, the peripheral profile of which forms cam profiles which will be better described below. 
   With reference to  FIG. 4 ,  26  overall indicates a cam element, mounted rotatably around the root part of the axial tang  23  of the driving element  24 , coaxially with and adjacent to the disc formation  25  of said driving element. 
   The cam element  26  has a peripheral cam profile, which will be better described below. 
   On the side opposite the driving element  24 , the cam element  26  has an integral toothed wheel formation  27  which engages with the toothed output wheel  13  of the speed reducer  12  associated with the electric motor  9  (see  FIGS. 3 and 4  in particular). 
   The diameters of the toothed wheel  13 , of the sprocket  14 , of the toothed wheel  19  and of the toothed gear  27  of the cam element  26  are such that during operation the driving element  24  and its cam formation or element  25  rotate at a relatively low predetermined angular velocity, while the cam element  26  is made to rotate at a relatively higher predetermined angular speed. For this reason, the cam formation or element  25  can be defined as the “slow cam” while the cam element  26  can be defined as the “fast cam”. 
   Indicatively, the speed of the fast cam  26  can be at least four times the speed of the slow cam for example. 
   With reference to  FIGS. 2 to 4  in particular,  28  indicates a support element fixed to the printed circuit board  16  and bearing a plurality of electric switches  29 - 31  ( FIG. 4 ) on one face. These electric switches are also visible in  FIG. 5  where the depiction of the support element  28  has been omitted. 
   Electric switch  29  in particular is intended to control the activation of the solenoid valve feeding water to the cavities or moulds  4  of the container  2 . 
   As can be seen in  FIG. 5  in particular, the switch  29  has a control lever  29   a  pushed elastically (in a manner known per se) against a feeler element  40  ( FIG. 5 ) mounted in an oscillatable manner at one end around a pin  42  essentially parallel to the axis of rotation of the cam elements  25  and  26 . The distal end of the feeler  40  has a terminal formation  43  which presses against the peripheral profiles of both the cam elements  25  and  26 . 
   With reference to  FIG. 5 , the cam elements  25  and  26 , slow and fast respectively, have at least one respective enabling profile, the conformation of which is suitable for allowing the feeler  40  to tend to arrange itself in a position of control of the opening of the solenoid valve feeding water to the cavities or moulds  4  of the container  2 . 
   In the embodiment illustrated as an example, the slow cam element  25  has at least one radially protruding profile  25   a , in which at least one interruption  45  in the circumferential direction, with an extension of about 20° for example, is defined. 
   The cam element  26  has a radially protruding cam profile  26   a  which also has an interruption in the circumferential direction, indicated by  46  in  FIG. 5 . This interruption is more extended angularly than the interruption  45  described above in relation to the fast cam element  25 . Only one end of the interruption  46  of the cam profile  26   a  of the element  26  is visible in  FIG. 5 , the other end being “covered” by the other components of the device. As an example only, the interruption  46  can have an extension of 90°. 
   The terminal formation  43  of the feeler element  40  is capable of engaging both the profile  25   a  of the slow cam element  25 , and the profile  26   a  of the fast cam element  26 . This feeler element  40  is pushed in the direction of these profiles by the control lever  29   a  of the electric switch  29 . Only when both interruptions  45  and  46  of the cam elements  25  and  26  are simultaneously facing the terminal portion  43  of the feeler element  40  can the feeler element  40  arrange itself in a position radially close to the axis of the driving element  24 , in which it permits a displacement of the control lever  29   a  of the switch  29  so as to provoke the switching of the same, and therefore the opening of the water feed solenoid valve. 
   The adoption of the mechanism with one slow cam that defines at least one enabling time window for the water feed function, and with one fast cam that, within such a time window, defines the water supply time interval, makes it possible to reduce the imprecision in the water feed time resulting from the manufacturing tolerances of the components and from the assembly of the same, at the very least to such an extent that no adjustment device is required nor are setting operations at the end of the production line. 
   Naturally, without prejudice to the principle of the invention, the forms of actuation and the embodiment details can be widely varied compared with what has been described and illustrated for non-limiting exemplificative purposes only, without thereby leaving the framework of the invention as defined in the annexed claims.