Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is entitled to benefit of a right of priority under 35 USC §119 from European patent application 12152579.4, filed 26 Jan. 2012, the content of which is incorporated by reference as if fully recited herein. 
     TECHNICAL FIELD 
     The disclosed embodiments concern a dosage-dispensing device for free-flowing dosage materials, specifically powders, granulates and pastes, with a support column and with a horizontal support arm that is cantilevered on the support column and includes a seat for an exchangeable dosage unit from which defined quantities of the dosage material are dispensed into a target container that is set up below the dosage unit, typically standing on a load receiver platform of a balance. 
     BACKGROUND 
     Dosage-dispensing devices with dosage units that normally include a source container and a dispensing head are used in particular for applications where small dosage quantities of, e.g., toxic substances are dispensed with high precision into small target containers. In many cases, the target container is placed on a balance in order to weigh the amount of substance dispensed from the dosage-dispensing device so that the latter can subsequently be processed further in accordance with a given purpose. 
     A dosage-dispensing device in which a dosage unit with a source container and a dispensing head can be emplaced is described in commonly-owned and co-pending US published application 2011/0220686. The source container is in essence a cylindrical container which, after having been filled with dosage material, is closed up with the dispensing head. The dispensing head includes a base unit which has an end surface and a coupling area for the source container or for a closure lid. Arranged in the end surface of the base unit is an outlet orifice which is connected to the coupling area. The dispensing head further includes a slide shutter which is held in a linear track in the base unit allowing guided movement parallel to the end surface. The slide shutter is controlled by an actuating member which is arranged on the base unit, rotatable about an axis that is orthogonal to the end surface, and includes a window, wherein for any position of the actuating member relative to the base unit, the outlet orifice lies within the area of the window. The slide shutter has a passage opening and is arranged between the base unit and the actuating member. By turning the actuating member relative to the base unit, the slide shutter can be moved in a straight line relative to the base unit and, in consequence, the aperture profile of the dispensing head can be varied as a result of the passage opening being shifted relative to the outlet orifice, and the stream of free-flowing material through the passage opening can be regulated. 
     In the operating position, the dosage unit installed in the dosage-dispensing device is oriented with the dispensing head facing downward and the outlet orifice located directly above the target container. The dosage unit therefore has to be already in the upside-down position when it is put into a seat of the dosage-dispensing device, or the dosage-dispensing device has to be equipped with seat that can be turned upside down and in which the dosage-dispensing unit can be secured by a restraining device against falling out. 
     A dosage-dispensing device with a seat for a dosage unit that can be turned upside down is shown in  FIG. 6  of US 2011/0220686 which has already been cited above. After it has been set into the seat in upright orientation, i.e. with the dispensing head on top, the dosage unit is locked in place by a holder ring which can swivel, slide and be locked on a guide rod, before the seat is turned upside down, whereby the dosage unit is brought into the operating position. 
     Especially in the interest of operating safety, it appears highly desirable to automate the function of locking and unlocking the dosage unit and in particular to couple the locking/unlocking function with the turning-over of the dosage unit in its seat in such a way that it is absolutely impossible for the dosage unit to drop out of the seat. However, based on  FIG. 6  and the accompanying description in US 2011/0220686 one has to conclude that the three steps of the securing procedure, i.e. the swiveling, sliding and locking of the holder ring have to be done manually by a human operator, before the seat with the dosage unit is turned upside down about a horizontal axis. 
     However, on closer examination of the securing concept with a holder ring that swivels, slides and locks on a guide rod, it is evident that a suitable actuating mechanism for this process would be relatively complicated and thus expensive. This clearly indicates a need for a fundamentally different concept to secure the dosage unit in the seat of the dosage-dispensing device. 
     Furthermore, in connection with the dosage-dispensing device of  FIG. 6  in US 2011/0220686, it is proposed to loosen up the dosage material by turning the dosage unit in its seat about a horizontal axis repeatedly back and forth in alternating succession before the dosage-dispensing process. However, for the loosening of the dosage material as well as for separating it from the inside wall of the source container, shock movements are much more effective than the comparatively gentle turning-over movement about the horizontal axis. 
     A present objective, then, is to provide a dosage-dispensing device with a seat for a dosage unit, wherein the dosage unit that has been placed into the seat is secured by a holder device against falling out when turned upside down and can furthermore be subjected to a shock movement to loosen up the dosage material, wherein the holder device as well as the device for generating the shock movement are designed for a simple automated mode of operation. 
     SUMMARY 
     This task is solved by a dosage-dispensing device as claimed below. Advantageous embodiments and details thereof are presented in the dependent claims. 
     A dosage-dispensing device for preparing measured quantities of free-flowing substances has a support column as well as a horizontal support arm which is cantilevered on the support column and includes a holder unit on which at least one movably supported receiving unit is arranged. The receiving unit is designed for at least one dosage unit to be put in place as well as to be taken out, wherein the holder unit contains at least one agitation actuator acting on the receiving unit. The movement of the receiving unit which is generated by the agitation actuator serves to loosen the dosage material which is located in the dosage unit. 
     The design of the dosage unit which normally includes a source container and a dispensing head is described and illustrated in detail in US 2011/0220686 which in regard to the content of its disclosure is hereby fully incorporated herein by reference. 
     After the dosage unit has been set in place in the receiving unit, it can be fastened to the receiving unit by means of a pre-tensioned clamping module. Fastened this way, the dosage unit is protected against falling out of its seat in the receiving unit. This is indispensable in particular in dosage-dispensing devices where the dosage unit is set into the receiving unit with the dispensing head up and is subsequently brought into the dispensing position by turning the receiving unit upside down. Besides, in order to effectively transmit the aforementioned movement for the loosening of the dosage material, it is likewise important that the dosage unit remains firmly tied to its seat in the receiving unit. To release the clamp when a dosage unit is to be put in or taken out, the clamping module is designed so that it can be spread apart from a dispensing position into a loading position by means of an opener module that is based on the holder unit, wherein the opener module is uncoupled from the receiving unit when the apparatus is in the dispensing position. In other words, the opener module is engaged and in contact with the clamping module only in the loading position in order to spread the clamping module apart and hold it open while the dosage unit is set in place or removed. 
     The clamping module in a preferred embodiment of the dosage-dispensing device includes at least one spring element which, in the dispensing position of the apparatus, is under pre-tension and thereby produces the clamping force. Especially practical is a solution where two identical halves of the clamping module are formed as stamped sheet metal parts and configured in such a way that they can be spread apart through elastic deformation, so that the function of the spring element is incorporated in the clamping module halves. However, it is also possible to produce the clamping module through other suitable manufacturing processes including for example die-casting, milling or laser-cutting. 
     A preferred embodiment of the clamping module has two clamping jaws. When the clamping module is in the dispensing position, the dosage unit is held between the two clamping jaws in a vertically defined and immovable position relative to the receiving unit. In relation to a vertical central axis of the dosage unit the clamping jaws are arranged diametrically opposite each other. 
     Advantageously at least one of the clamping jaws is equipped with a position-defining element. Through mutual engagement between the position-defining element and a complementary surface feature that is formed on the dosage unit, the latter can be set into the receiving unit in a defined rotary position relative to the vertical central axis. 
     The clamping module in preferred embodiments is fastened to the receiving unit. Accordingly, the clamping module is a part of the receiving unit and therefore participates in the movements of the receiving unit during the dispensing process. 
     The opener module has preferably two pusher arms which are designed to push apart the two clamping jaws of the clamping module so that the dosage unit can be put in place or taken out. 
     Each pusher arm has a first end and a second end. The first end of each pusher arm is pivotally connected to the holder unit, while the opposite, second end of the pusher arm is arranged in a free space between the dosage-dispensing unit and the clamping jaw. 
     It is advantageous if the second end of each pusher arm has a nose-shaped contour projection directed towards the respective clamping jaw so that, in the interest of a compact design, the free space between the dosage unit and the clamping jaw can be kept as narrow as possible. Especially for cylindrical dosage units, this design feature is conducive to a compact arrangement. 
     As mentioned above, in the dispensing position the opener module is uncoupled from the receiving unit. In the dispensing position, the second ends of the pusher arms are therefore removed from contact with the receiving unit and with the clamping module that is connected to it. 
     In a preferred embodiment of the opener module, the pusher arms can be moved from the dispensing position to the loading position by means of a rotatable actuator element. The actuator element can be configured for example as a rotatable disk with an elliptical guide track. Through the cooperation of the guide track with pins that are arranged on the pusher arms, a rotation of the actuator element causes the pusher arms to move from the closed position into the spread-apart loading position. 
     The movable constraint of the receiving unit on the holder unit is preferably realized in the form of a flexible connection, for example through an arrangement where the receiving unit is movably constrained to the holder unit by elastic parallel-guiding members. 
     The at least one agitation actuator which is based in the holder unit and acts on the receiving unit includes preferably a motor which, by way of a cam- or contour disk, imparts shaking- or shocking movements to the resiliently constrained receiving unit with the purpose of loosening the dosage material contained in the dosage unit. 
     In preferred embodiments of the dosage-dispensing device, the support arm on the support column can be turned about a horizontal axis H from a loading position into a dispensing position. However, the invention also covers embodiments where the support arm is not movable and the dosage unit is therefore not turned upside down after it has been set into the receiving unit. In this case, too, it is still important to retain the dosage unit firmly in its seat in the receiving unit in order to allow the aforementioned shaking- and shocking movements to be transmitted effectively to the dosage material contained in the dosage unit. 
    
    
     
       BRIEF DESCRIPTION 
       Details of the dosage-dispensing device will become apparent from the description of the examples of embodiments that are illustrated in the drawings, wherein identical parts are identified by identical reference numbers and wherein: 
         FIG. 1  is a perspective view of a schematic embodiment of the dosage-dispensing device with the support arm in loading position and with a dosage unit in place; 
         FIG. 2  is an exploded view of a dosage unit according to the state of the art; 
         FIG. 3  is a detail view of the support arm of the  FIG. 1  dosage-dispensing device in loading position, but without a dosage unit; 
         FIG. 4  shows the support arm of  FIG. 3  in dispensing position; 
         FIG. 5  shows the support arm of  FIG. 3  in loading position with the view directed at the pushed-apart clamping module and opener module; 
         FIG. 6  shows the support arm of  FIG. 3  in dispensing position with the view directed at the closed clamping module and opener module; 
         FIG. 7  shows the support arm of  FIG. 3  in dispensing position seen from the side, with pushed-apart clamping module; 
         FIG. 8  is a schematic view of a second embodiment of the clamping module in dispensing position; 
         FIG. 9  is a schematic view of the second embodiment of the clamping module in loading position; and 
         FIG. 10  is a schematic representation of the actuating functions to which the dosage unit in the dosage-dispensing device is subjected. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates the principal arrangement of a dosage-dispensing device with a support column  2  which holds a support arm  10  with the ability to rotate about a horizontal axis H as indicated by the circular arrow  3 . The support arm  10  includes a holder unit  20  as well as a receiving unit  30  which is movably supported on the holder unit  20 . Seated in the receiving unit  30  is a dosage unit  70  which includes a source container  71  and a dispensing head  72  and whose configuration is described in detail in US 2011/0220686 which has been cited above. The holder unit  20  includes at least one agitation actuator (not visible in  FIG. 1 ) to generate the movement indicated by the bidirectional arrow  31  which serves to loosen and to discharge the dosage material that is contained in the dosage unit  70 . The dosage-dispensing device  1  in  FIG. 1  is shown in loading position, where the dosage unit  70  is set into the receiving unit  30  with the source container  71  first, i.e. with the dispensing head  71  pointing upward. This orientation of the dosage unit  70  is preferred for the storage of pre-filled dosage unit, because it prevents the risk that the outlet orifice  78  could become clogged up by compacted dosage material. For the dispensing process, the dosage unit  70  is secured in its seat  32  in the receiving unit  30  as will be described below and turned upside down through the aforementioned rotation  3  about the horizontal axis H, so that the outlet orifice  78  is located above the target container  6  which is standing on the weighing pan  5  of a balance  4 . The support column  2  can have a stationary bottom part  7  and top part  8  which can be raised and lowered as indicated by the bidirectional arrow  9 , so that the vertical position of the support arm  10  is adaptable to target containers  6  of different heights. The balance  5  can be a unit that is permanently connected to the dosage-dispensing device  1 , or it could also be a free-standing laboratory balance which is arranged below the support arm  10 . 
     As can be seen in  FIG. 2  (which has been taken over from US 2011/0220686), a dosage unit  70  that fits into the seat opening of the receiving unit  30  is essentially cylindrical and includes a source container  71  as well as a dispensing head  72 . The dispensing head  72  includes a base unit  73  designed to be screwed onto the source container  71 , a slide shutter  75  which is constrained for linear movement in a guide track  74  of the base unit  73 , as well as an actuating member  76  which fits over the base unit  73  like a cup and can be turned relative to the base unit  73 . With a rotary movement of the actuating member  76  about the cylinder axis Z of the dosage unit, an eccentric  77  which is formed on the inside of the actuating member  76  causes the slide shutter  75  to change its position, whereby the aperture profile of the outlet orifice  78  can be varied continuously between the open and the closed position. 
     In a perspective view directed at an angle from above,  FIG. 3  shows a detailed representation of the support arm  10  of the dosage-dispensing device  1  in the loading position, including the holder unit  20  and the receiving unit  30 , but without a dosage unit  70  in the seat  32 . One will note in particular the clamping module  60  with the two clamping jaws  61  shown here in the loading position, i.e. spread apart. In the illustrated embodiment, the clamping jaws  61  are sheet-metal stampings made of a spring-elastic material and are fastened to the sides of the receiving unit with screws. In the dispensing position, i.e. when the clamping module  60  is not pushed apart, the dosage unit  70  or, more specifically, the actuating member  76  of the dispensing head  72  is held between the two clamping jaws  61  in a vertically defined and immovable position relative to the receiving unit  30 . In relation to the seat  32  the clamping jaws  61  are arranged diametrically opposite each other. At least one of the clamping jaws  61  is equipped with a first position-defining element  62 , configured here as a first indent  62  in the contour of the clamping jaw  61  that is farther away from the viewer. Through mutual engagement between the first indent  62  and a complementary projection  79  of the actuating member  76  of the dispensing head  72  (see  FIG. 2 ), the actuating member  76  is held in a defined rotary position relative to the receiving unit  30 . The hollow cylindrical seat  32 , on the other hand, is rotatably supported in the receiving unit  30  and carries at its upper rim a second position-defining element  33  in the form of a second indent  33  which, through mutual engagement with a complementary projection  80  of the base unit  73  (see  FIG. 2 ) transmits a rotary movement of the seat  32  to the base unit  73 . As explained above with the help of  FIG. 2 , turning the base unit  73  relative to the actuating member  76  causes a linear movement of the slide shutter  75 , whereby the discharge of dosage material from the outlet orifice can be controlled. The required rotary movement of the seat  32  is generated by a position-setting module  85  with a second actuator motor  86  which is arranged at the forward-facing side (in  FIG. 3 ) of the holder unit  20  and connected to the rotatable seat  32  through a revolving motion-transmitting means  87 . 
       FIG. 4  shows the same support arm  10  in the dispensing position. In the upper part of the drawing, the actuator mechanism  23  can be seen which generates the movement of the receiving unit  30  (as indicated in  FIG. 1 ) for the loosening of the dosage material in the dosage unit  70 , and in the lower part the opener module  40  which actuates the opening and closing of the clamping jaws  61 . The actuator  50  and the opener module  40  will be described in detail below in the context of  FIGS. 5 to 7 .  FIG. 4  further illustrates the design of the clamping module  60 , whose identical halves are produced as stampings of a flat elastic material, with a spring portion or spring element  63  formed between the fastening area  64  and the clamping jaw  61 , so that in the dispensing position the clamping jaws  61  are pressed against the actuating member  76  of the dosage unit  70  (see  FIG. 2 ) by a pre-tension of the spring elements  63 .  FIG. 4  further illustrates how the position-setting module  85  (see  FIG. 3 ), by way of a revolving motion-transmitting means  87 , for example a drive belt  87  with a drive pulley  88  and a tensioning pulley  89 , sets the rotary position of the seat  32  to which the base unit  73  of the dispensing head  72  is locked in joint rotation, wherein the rotary position of the base unit  73  relative to the actuating member  76  determines, through the slide shutter  75  (see  FIG. 2 ) the aperture profile of the outlet orifice  78 . 
     In  FIGS. 5 and 6 , which show the support arm  10 , the view is directed at the clamping module  60  and the opener module  40  in loading position ( FIG. 5 ) and in dispensing position ( FIG. 6 ). The two pusher arms  41  of the opener module  40  have first ends  42  pivotally connected to the base plate  21  of the holder unit  20 . In the loading position shown in  FIG. 5 , the nose-shaped second ends  43  of the pusher arms  41  are pushing from the inside against the two clamping module halves, whereby the clamping jaws  61  are spread open. In the dispensing position shown in  FIG. 6 , on the other hand, the second ends  43  of the pusher arms  41  are removed from contact with the clamping module halves, so that the clamping jaws  61  are pressed by the pre-tension of the spring elements  63  against the actuating member  76  of a dosage unit  70  that is in the seat  32 . Each of the pusher arms  41  carries a guide pin  44  between the first and the second end. The guide pins  44  extend through openings  22  ( FIG. 7 ) in the base plate  21  into the interior of the opener module  40 , where they are engaged in an elliptical guide track  48  of the rotatable actuating element  47 , so that a 90° turn of the actuating element  47  moves the pusher arms  41  between the open and the closed position. In the loading position as shown in  FIG. 5 , the elliptical guide track  48  (drawn with dotted lines) is oriented with its longer main diameter transverse to the pusher arms, so that the pusher arms  41  are held in the maximally open position by the guide pins  44 . In the dispensing position shown in  FIG. 6 , on the other hand, the shorter main diameter of the elliptical guide track  48  is oriented transverse to the pusher arms, so that the latter are held in the maximally closed position by the guide pins  44 . 
       FIG. 7  serves to illuminate details of  FIGS. 4 to 6  showing again in a side view the support arm  10  with the actuator  50  in the upper part and the opener module  40  in the lower part of the holder unit  20 . The actuator  50  includes a parallel-guiding mechanism with a first parallelogram leg  53  firmly attached to the holder unit  20  and with a second, movable parallelogram leg  54  which supports the receiving unit  30  and is constrained to the first parallelogram leg  53  by parallel-guiding members  55 , so that the receiving unit can move up and down in relation to the holder unit  20  within a limited vertical range. A drive motor  51  mounted on the rear wall (relative to the viewer) serves to impart by way of the cam disk  52  a shocking or shaking movement to the second parallelogram leg  54  with the connected receiving unit  30  for the purpose of loosening the dosage material inside the dosage unit  70 . 
     The drive mechanism inside the holder unit for the opener module  40  includes a first actuator motor  45 , a reduction gearbox  46 , as well as the actuator element  47  which is configured as a disk-shaped gear  47  carrying on its underside next to the base plate  20  the elliptical guide track  48  that engages the guide pins  44  of the pusher arms  41  which protrude through the openings  22  of the base plate  20 . The opener module is active only during short work phases in which the first actuator motor  45  turns the actuating element  47  by 90° and, by way of the elliptical guide track  48  and the guide pins  44 , controls the opening and closing of the pusher arms  41 , as the longer main diameter of the elliptical guide track  48  is oriented alternatingly in the transverse and lengthwise direction of the support arm  10 . 
       FIGS. 8 and 9  show a schematic cross-sectional view of an alternative, second embodiment in a plane that is orthogonal to the horizontal axis H and contains the central axis Z. The support arm still includes a holder unit with an opener module and an actuator as well as a receiving unit with a clamping module. In contrast to the embodiment of  FIGS. 3 to 7  which has been described above, the support arm in the embodiment of  FIGS. 8 and 9  is not rotatable about a horizontal axis H. In the loading phase, the dosage unit  170  is set into the receiving unit  130  with the dispensing head  172  already facing downward, with the shoulder of the source container resting on a ledge  134  of the seat  132 . The two halves of the clamping module  160  in this example are not formed as stampings of an elastic sheet material, but are of a rigid, non-elastic design and have a pivoting connection to the receiving unit (not shown in detail) to enable their mobility between the dispensing position ( FIG. 8 ) and the loading position ( FIG. 9 ). Spring elements  163  in the form of tensile springs press the clamping jaw  161  in the dispensing position against the actuating member of the dispensing head  172  and in the loading position against the spread-apart pusher arms  141  of the opener module. 
     Except for differences in the detail design of the clamping module  160  in  FIGS. 8 and 9 , it should be emphasized here that the inventive concept of a clamping module which can be closed and opened with an opener module can also be advantageously employed in dosage-dispensing devices where the support arm is not rotatable and where the dosage unit is thus not being turned upside down after it has been set into the receiving unit. This applies in particular to dosage-dispensing devices that are equipped with an actuator to generate shaking- or shocking movements, during which the dosage unit must remain in solid contact to its seat in the receiving unit in order to ensure that the movements are transmitted to the dosage material to produce the desired loosening effect. 
       FIG. 10  schematically illustrates the receiving unit of  FIGS. 3 to 7  in a sectional plane that is orthogonal to the horizontal axis H and contains the cylinder axis Z of the dosage unit  70 . The purpose is to clarify once more and in general terms—i.e. independent of specific implementations of individual modules and elements—the functions to which a dosage unit of a dosage-dispensing device  1  is subjected, namely:
         holding the dosage unit  70  secured in the receiving unit  30 , for which purpose the actuating member  76  of the dispensing head  72  is clamped through spring tension between the clamping jaws  61  of the clamping module  60 , wherein the clamp grip can be released and activated by swiveling the pusher arms  41  of an opener module  40  between an open and a closed position;   opening and closing the outlet orifice  78  to a variable extent, which is accomplished with a position-setting module  85  (see  FIG. 3 ) turning the seat  32  (horizontally hatched part in  FIG. 10 ) in the receiving unit  30  (diagonally hatched) about the central axis Z and thereby turning the base unit  73  (which is taken along in the rotation) with the screwed-on source container  71  against the actuating member  76 ;   loosening the dosage material contained in the dosage unit  70  through a shocking- or shaking movement (indicated by the arrow  31 ) by means of an actuator  50 ; and   (if the apparatus has the requisite capability) turning the dosage unit  70  upside-down about a horizontal axis H (indicated by the circular arrow  3 ) by turning the support arm  10  relative to the support column  2 .       

     Although the invention has been described through the presentation of specific examples of embodiments, it will be evident to the reader that numerous further variant embodiments could be developed from the teachings of the present invention, wherein for example the movement of the clamping jaws between the pulled-apart loading position and the clamped-down dispensing position could be controlled by the actuating force of electromagnets that are switched on or off. It is also conceivable that the pusher arms of the opener module are force-biased in the closing direction by a tensile spring and that the guide pins glide along the outside edge of an elliptical contour disk instead of in an elliptical guide track. It goes without saying that any such variations of the examples described herein with design elements that are familiar to practitioners in the relevant technical field are considered to be within the scope of the present invention.

Technology Category: 3