Patent Abstract:
Container comprising
   a first element  2  and at least a second element  3  movable relative to the first element  2  between a closed position and an open position, and a drive device  5  for moving the second element  3,      wherein at least one deformation measuring unit  6  is provided with a deformation sensor  11  on at least one of the elements  2, 3  for detecting a force exerted on one of the elements  2, 3  and   wherein a control unit  12  is provided for receiving and evaluating a deformation signal transmitted by the deformation measuring unit  6  and is provided for actuating the drive device  5.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the U.S. national stage of PCT/EP2014/059535 filed May 9, 2014, which claims priority of German Patent Application 10 2013 104 866.8 filed May 11, 2013. 
     FIELD OF THE INVENTION 
     The invention relates to a container having a first element and at least a second element movable relative to the first element between a closed position and an open position, as well as a drive device for moving the second element. The container can be a piece of furniture, a household appliance, as for example a kitchen appliance or built-in kitchen appliance, or a vending machine. 
     BACKGROUND OF THE INVENTION 
     A piece of furniture of the above named type is known from WO 2008/141348 A2. The piece of furniture has a first element in form of a furniture shell and a second element in form of a movable flap. By means of the drive device, the flap can be automatically transferred into an open or a closed position. For actuating, i.e. switching-on the drive device, a switching element is provided. The switching element is arranged and formed such, that by a movement of the flap caused by a user, the drive device is actuated. In this case, the flap is arranged in its closed position such, that it covers the switching element and abuts the same. Because of a pressure loading onto the flap in direction towards the piece of furniture a pressure switch of the switching element is switched and the drive device is actuated. In this case, a sufficient large compression path has to be provided for the pressure switch and thus for the flap, which compression path has to be provided between the flap and the piece of furniture. This can, for example, be ensured by a spring buffer. It can be disadvantageous, that with each pressure application onto the flap the drive device is actuated and the flap is transferred into the open position, even when the flap was pushed accidentally. WO 2008/141348 A2 proposes alternatively to provide a position measuring device, by means of which also the velocity and acceleration of the movement of the flap can be calculated. This allows, that driving of the flap by means of the drive device is carried out in dependency of the determined sizes of the flap. In this case, also a corresponding pushing path has to be provided via spring buffers. A further alternative, which is proposed in WO 2008/141348 A2, are capacitive switching elements, which operate free of contact. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a container of the above named type, in which it is possible to realise that for actuating the drive device, an as small as possible path, which preferably is not noticeable for the user, can be achieved for actuating an actuating device. 
     The object is met according to the invention by a container, which comprises a first element and at least one second element movable relative to the first element between a closed position and an open position as well as a drive device for moving the second element, wherein at least one deformation measuring unit is provided with a deformation sensor on one of the elements for detecting a force exerted on one of the elements, and wherein a control unit is provided for receiving and evaluating a deformation signal transmitted by the deformation measuring unit and for actuating the drive device. 
     A deformation sensor has several advantages compared to commonly used switching elements. The deformation sensor detects the deformation of a component and transmits it as a deformation signal, wherein the course of the deformation changes can be read. This means, that not a digital/binary signal is transmitted, as this is the case in a switching element, but makes an analog course of deformation or a deformation change available as deformation signal. The term “analog” does not mean, that the deformation signal cannot be scanned digitally and can be transmitted as a digital signal. It is, rather, meant, that not only two conditions of a measuring value, as this is the case in a switching signal (on/off), can be determined, but an analog signal or a digitally determined signal of a course of measuring values with an accuracy depending on the digital resolution. 
     This has the advantage, that assembly tolerances of the two element towards each other and the deformation measuring unit have no influence, when the drive device is actuated. Commonly used switching elements have a precise switching point, when reaching it or exceeding it, the switch is switched from one condition to another condition. Thus, it is clearly set, in which position of the switching element the drive device is actuated. The position of this switching point depends on the assembly tolerances. Especially then, when the drive device is actuated by a force exerted on an element of the container, i.e. the switching element is switched indirectly, e.g. via a flap of the container, the switching point is pre-set by the assembly tolerances. This is not the case, when using a deformation sensor. In this case, only an initial initialization has to take place, so that the control unit is taught such, that it knows at given assembly conditions the deformation signal, existing in the closed position, as a reference point and starting from this reference value can process relative deformation changes. 
     Preferably, the container is a piece of furniture or a household appliance, especially a fully integrated kitchen appliance. The first element can be a furniture shell and the second element can be an element held movable relative to the shell, especially a lid, a flap, a drawer or a door. 
     The deformation sensor is preferably a sensor for recording a relative deformation change, especially a piezo element with a piezo crystal or a strain gauge. Piezo elements and strain gauges have the advantage, that they enable deformation signals, which can already be evaluated during deformations, which are not noticed by a user. 
     The second element can be supported via the deformation measuring unit on the first element. The deformation measuring unit can, for example, be arranged on a first element in form of a shell of a piece of furniture, wherein the second element, for example in shape of a flap or a lid, is supported on the deformation measuring unit. The deformation measuring unit can be incorporated in a side wall of the shell such, that the deformation sensor projects slightly over the front edge of the side wall, so that the flap can come into abutment with the deformation sensor. In this case, the flap completely covers in the closed position the deformation measuring unit, so that it is not visible to the user. By of a force exerted from the outside onto the flap in direction towards the shell of the piece of furniture and, thus, towards the deformation sensor, the deformation signal thus produced is changed, whereby an actuation of the drive device can be triggered. Especially, when the deformation sensor is a piezo element with a piezo crystal, the necessary path or the necessary deformation is so small, that it is not noticed by a user, which leads to a pleasant haptical feeling during the actuation of the flap or of the drive device. Furthermore, such a deformation measuring unit can also be used in containers, in which sealing elements are provided between the shell of the piece of furniture and the flap or the first element and the second element, which only have to be deformed by a very small amount, to actuate the drive device. 
     The deformation measuring unit can have an accommodation element accommodating the deformation sensor, wherein the accommodation element is mounted in or on the first element. In this case, the second element is supported on the deformation sensor. 
     Furthermore, in the accommodation element an additional switch for actuating the drive device can be integrated. This can, especially, be of advantage, when the container is a wall unit with a flap moving upwards. By means of a pressure application onto the flap arranged in the closed position, the drive device can, as described above, be actuated, as the flap is supported via the deformation measuring unit on the shell. As soon as the flap is in the open position, a further device has to be provided, to move the flap again back into the closed position. This is achieved by a switch, which is preferably arranged in the accommodation element of the deformation measuring unit. Thus, no separate switching unit has to be provided. The present deformation measuring unit can be used, which then represents a single component with the deformation sensor and switches. 
     The deformation measuring unit can also be arranged on a component, especially a front of one of the elements. The deformation measuring unit does not have to be arranged between the two elements. The deformation can for example be detected by means of a strain gauge on a front of the second element. It is also possible, that the deformation measuring unit is arranged on the first element, for example on or in a shell, wherein even during a force loading on the second element, the deformation can be determined in the first element, insofar as the second element is supported on the first element. Thus, the deformation measuring unit can be arranged such, that it is not visible to a user. 
     Preferably, one of the elements, for example the second element, includes a first component and a second component, wherein the deformation measuring unit is arranged between the two components. Thus, a deformation or displacement of the two components relative to each other can be determined. 
     In this case, the first component of the second element can be represented in form of a front and the second component in the form of a support element, wherein the support element is, for example, a frame, which is displaceable within the first element and supports the front. 
     In a preferred embodiment the deformation sensor is formed like a plate and is arranged such, that it is bent during a force loading on the first component. Alternative, also a deformation sensor can be provided, which is stressed by compression. 
     In the preferred embodiment, the deformation measuring unit has an accommodation element accommodating the deformation sensor. The accommodation element is supported on the first component and on the second component. 
     In this case, the accommodation element can be formed with a pressure portion supporting the first component. The accommodation element has then preferably two support portions supporting the accommodation element on the second component. The deformation sensor is supported on a first side on the pressure portion and on a second side, facing away from the first side, on the support portions. Thus, during a displacement of the pressure portion relative to the two support portions, a deformation of the deformation sensor takes place. 
     As the deformation sensor records relative deformation changes, it can be provided, that the deformation sensor is held prestressed between the pressure portion and the support portions. Thus, always a deformation signal is provided, even when no deformation of the two components to each other or of one of the components has taken place. Thus, an existing play, which would lead to a measuring inaccuracy, is removed. 
     The pressure portion can have an attachment portion, wherein attachment projections of the second component are clamped between the attachment portion and the support portions. A deformation of the accommodation element is achieved during a force loading in the area between the two support portions, which can be detected by the deformation sensor. 
     Furthermore, the object is met by a method for actuating a drive device of a container according to the above type, wherein the course of the relative deformation change is evaluated by using of the deformation signal and by actuating the drive device when specific conditions are met. In this case, the deformation signal is evaluated such, that an unintended actuation of the drive device is prevented. Depending on the force loading, a specific course of the deformation signal is achieved, wherein by means of the course of the deformation signal it can be differentiated between different force loadings. The force loading onto the deformation measuring unit for example during a switching movement of a person can clearly be distinguished, from the course of the deformation signal during an unintended hitting or leaning against the second element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments are described in detail in the following using the figures and herein it shows: 
         FIG. 1  a perspective representation of a cabinet having a shell and a lid in its closed position; 
         FIG. 2  a cabinet of  FIG. 1  having a lid in its open position; 
         FIG. 3  a perspective representation of a deformation measuring unit of  FIGS. 1 and 2 ; 
         FIG. 4  an internal view of the cabinet having the deformation measuring unit of  FIG. 3 ; 
         FIG. 5  a second embodiment of a cabinet with a shell and a pullout/drawer; 
         FIG. 6  a perspective view of a deformation measuring unit for the application in a cabinet of  FIG. 5 ; 
         FIG. 7  a cross-sectional view along the intersection line VII-VII of  FIG. 6  and 
         FIG. 8  a cross-sectional view through a part of the pullout/drawer of the cabinet of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 and 2  show a first embodiment of a container according to the invention, wherein the container is formed as a cabinet  1  and comprises a first element in form of a shell  2  and a second element in form of a lid  3 . The lid  3  is connected via a drive device  5  in form of a lid opener to the shell  2  and can be moved relative to the shell  2  from the closed position shown in  FIG. 1  to the open position shown in  FIG. 2 . The drive device  5  includes, in this case, an electric drive (e.g. an electric motor), which enables an automatic displacement of the lid  3 . 
     The shell  2  has a side wall  4 , into which a deformation measuring unit  6  is incorporated. The deformation measuring unit  6  is shown in detail in  FIGS. 3 and 4 .  FIG. 4  shows a partial cross-sectional view through the cabinet  1  of  FIG. 1  with the lid  3  in its closed position. Furthermore, the deformation measuring unit  6  is shown schematically in a longitudinal sectional view. 
     The deformation measuring unit  6  includes an accommodation element in form of a housing  7 . The housing  7  is received in a recess  8  of the side wall  4 . The recess  8  starts from an end face  10  as well as from an inner face  14  of the side wall  4 . The end face  10  is facing the lid  3 , wherein the lid  3  covers the end face  10  in the closed position. The deformation measuring unit  6  comprises a sensing arm  9 , which is, in the present example, formed integrally with the housing  7  and is arranged deformably relative thereto. Preferably, the housing  7  is manufactured from plastic, so that the sensing arm  9  is connected via a film hinge  16  to the housing  7  and is elastically movable. In this case, the sensing arm  9  projects over a front face  13  of the housing  7  and over the end face  10  of the side wall  4 . The lid  3  is, as can be seen in  FIG. 4 , supported in its closed position via the sensing arm  9  on the deformation measuring unit  6  and, thus, indirectly on the shell  2 . 
     In the inner of the housing  7 , a piezo element  11  is arranged, which is schematically shown in  FIG. 4 . By means of a force loading on the sensing arm  9  in direction of the piezo element  11 , a force is thus acting on the piezo element  11 , which comprises a piezo crystal, so that a deformation signal is produced by the piezo element  11 . The deformation signal is transmitted to a control unit  12 , which is an integral component of the deformation measuring unit  6  or is provided as a separate unit, which is connected via a common data connection, for example a radio link or a cable connection, to the deformation measuring unit  6 . The control unit  12  is, furthermore, connected via common data connections to the drive device  5 , so that during a force loading on the lid  3  via the sensing arm  9  onto the piezo element  11 , an actuation of the drive device  5  is possible. 
     On the side of the deformation measuring unit  6 , which projects from the side wall  14  out of the recess  8 , a separate switch  15  is provided. The switch  15  can be actuated manually, so that when the lid  3  is open, the lid  3  can be transferred by means of the easy reachable switch  15  from its open position again into its closed position. For this the switch  15  is also connected to the control unit  12  via a data connection. 
     In  FIGS. 5 to 8 , a second embodiment of a container according to the invention is shown in the form of a cabinet  30 , having a first element in form of a shell  31  and a second element in the form of a pullout/drawer  32 . In  FIG. 5  the shell  31  is shown schematically by indication of the outer edges. The pullout  32  includes a front  33  ( FIG. 8 ) and a support element  34 . The support element  34  is arranged linearly displaceable within the shell  31  and is driven electrically by a drive device  35 , so that by actuating the drive device  35  the pullout  32  can be driven out and again back into the shell  31 . A solution may also be considered, in which the pullout is only expelled a bit from the shell  31  and the further movement is achieved by free-wheeling or manually. Several shelves  36  are arranged on the support element  34  for storing objects. Between the front  33  and the support element  34 , a deformation measuring unit  37  is provided, which actuates the drive device  35 . 
     The deformation measuring unit  37  is shown in detail in  FIGS. 6 to 8 . The deformation measuring unit  37  comprises a deformation sensor  38 , formed plate-like. The deformation sensor  38  is not shown in  FIG. 6  for clarity. The deformation measuring unit  37  includes further an accommodation element  39 , formed frame-like. The deformation sensor  38  is mounted on the accommodation element  39 . The accommodation element  39  has a fixing portion  40  with a circular through opening  41 . Towards one side, the through opening  41  has an annular fixing recess  42 , into which the deformation sensor  38  can be inserted. A pressure arm  56  with a central pressure projection  59  projects radially from the edge of the through opening  41  up to the center of the through opening  41 . The deformation sensor  38  is arranged between the pressure arm  56  and the fixing recess  42  or is held by the pressure arm  56 . The pressure arm is supported with a pressure projection  59  on the deformation sensor  38 , in the fixing recess  42 . Thus, the deformation sensor  38  is fixed on the accommodation element  39 . 
     The accommodation element  39  has further a pressure portion  43 , which is arranged centrally to a longitudinal axis L of the accommodation element  39 . The pressure portion  43  has an attachment portion  44 , which comprises two tabs  45 ,  46 , projecting respectively from one side of the longitudinal axis L. 
     Two support portions  47 ,  48  of the accommodation element  39  are provided on both sides of the longitudinal axis L. 
     For attaching the accommodation element  39 , the support element  34  has a vertically extending pillar  49  with an also vertically extending attachment groove  50 . The attachment groove  50  is facing the front  33 . The attachment groove  50  is flanked along its longitudinal extension direction at both sides by plate-like attachment projections  51 ,  52 , which form together with the attachment groove  50  respectively an undercut. The accommodation element  39  is inserted with the attachment portion  44  into the attachment groove  50  such, that the tabs  45 ,  46  engage behind the attachment projections  51 ,  52 , wherein the tabs  45 ,  46  are supported on the latter on the side of the attachment projections  51 ,  52  facing the attachment groove  50 . The support portions  47 ,  48  are supported on the side of the attachment projections  51 ,  52  facing away from the tabs  45 ,  46  on the pillar  49 . The accommodation element  39  is, in this case, preferably dimensioned such, that the attachment projections  51 ,  52  are clamped with bias between the tabs  45 ,  46  and the support portions  47 ,  48 . 
     In this case, the accommodation element  39  is arranged between the pillar  49  of the support element  34  and the front  33 , so that a loading force is introduced in the force introduction direction P. The accommodation element  39  is deformed via the pressure portion  43 . The accommodation element  39  is supported on the front  33 , wherein this deformation is transferred to the deformation sensor  38 . During a deformation in force introduction direction P, the attachment portion  44  is pushed deeper into the attachment groove  50 , wherein the tabs  45 ,  46  lift off the attachment projections  51 ,  52 . To facilitate this deformation, the support portions  47 ,  48  have support projections  53 ,  53 ′,  54 ,  54 ′, which project in direction towards the pillar  59  from the support portions  47 ,  48  and by means of which the support portions  47 ,  48  are supported on the pillar  49 . The support projections  53 ,  53 ′,  54 ,  54 ′ are formed burled and form thus points of rotation, around which the accommodation element  49  can pivot during deformation. 
     The attachment portion  44  comprises further a bore  55 , which is aligned with the attachment groove  50  and extends starting therefrom in direction to the front  33 . The attachment portion  44  can be rigidly screwed to the front  33  via the bore  55  or can be connected in any other way. Thus, also a force in opposition to the force introduction direction P can be achieved, wherein in this direction, the tabs  45 ,  46  are supported on the attachment projections  51 ,  52  and no deformation of the accommodation element  39  is produced. Thus, the deformation measuring unit  47  can also be used for pullouts  32 , which have a drawbar on the side of the front  33  facing away from the pillar  49 . The deformation measuring unit  47  behaves elastically, thus, when a force is produced in an opposite direction to the force introduction direction P and is rigid against the force introduction direction P. 
     The pressure arm  56  on the pressure portion  43  serves also for the better transmission of the deformations of the accommodation element  39  onto the plate-like deformation sensor  38 . The pressure arm  56  projects radially into the through opening  41  and is supported centrally on the deformation sensor  38 . Thus, a pressure force, which acts in the force introduction direction P onto the front, is transmitted centrally onto the deformation sensor  38  and ensures a sufficient deformation of the deformation sensor  38  also at low pressures. 
     The accommodation element  39  has a web  57 , on which end a control unit  58  is mounted. The control unit  58  receives via a common data connection the deformation signal of the deformation sensor  38  and processes this. Furthermore, the control unit  58  is connected to the drive device  35  via a data connection, like for example a cable connection or a radio link, to be able to actuate the drive device  35 . 
     REFERENCE NUMERALS LIST 
     
         
           1  cabinet 
           2  shell 
           3  lid 
           4  side wall 
           5  drive device 
           6  deformation measuring unit 
           7  housing 
           8  recess 
           9  sensing arm 
           10  front face 
           11  piezo element 
           12  control unit 
           13  end face 
           14  inner face 
           15  switch 
           16  film hinge 
           30  cabinet 
           31  shell 
           32  pullout/drawer 
           33  front 
           34  support element 
           35  drive device 
           36  shelf 
           37  deformation measuring unit 
           38  deformation sensor 
           39  accommodation element 
           40  fixing portion 
           41  through opening 
           42  fixing recess 
           43  pressure portion 
           44  attachment portion 
           45  tab 
           46  tab 
           47  support portion 
           48  support portion 
           49  pillar 
           50  attachment groove 
           51  attachment projection 
           52  attachment projection 
           53  support projection 
           54  support projection 
           55  bore 
           56  pressure arm 
           57  web 
           58  control unit 
           59  pressure projection 
         L longitudinal axis 
         P direction of the force introduction

Technology Classification (CPC): 0