Abstract:
A head ( 5 ) is associated with a device ( 1 ) for dispensing measured dosages of a free-flowing material. The head has housing ( 3 ) with an interior space ( 59 ) with a fill opening ( 57 ) and a discharge orifice ( 62 ). A shutter bolt ( 80 ) is arranged in the housing to open and close the discharge orifice ( 62 ) and to loosen and advance the material. The head ( 5 ) has a dispensing position, in which the shutter bolt is oriented substantially vertically and a fill position. In the dispensing position, the material is dispensed through the discharge orifice ( 62 ). In the fill position, material is filled through the fill opening ( 57 ), which is positioned laterally on the housing when the head is in the dispensing position. A rest surface ( 51 ) is diametrically opposite the fill opening, so that the head lies on its rest surface in the fill position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is entitled to benefit of a right of priority under 35 USC §119 from European patent application 13177422.6, filed on 22 Jul. 2013, the content of which is incorporated by reference as if fully recited herein. 
       TECHNICAL FIELD 
       [0002]    The invention concerns a dispensing head which can be used as a part of a dosage-dispensing device that serves to dispense measured quantities of free-flowing substances, specifically powders and pastes. 
       BACKGROUND 
       [0003]    Dosage-dispensing devices are generally used for the purpose of dispensing small, precisely measured quantities of critical, for example toxic, substances into a target vessel. The latter is normally set on a balance, so that the weight of the dispensed substance can be monitored during the dispensing process and the further discharge of substance into the target vessel can be stopped when the target weight has been reached. 
         [0004]    Instruments of the current state of the art such as for example the dosage-dispensing device described in commonly-owned EP 1930702 A1 (also available as U.S. Pat. No. 8,245,883 B2) are characterized by a two-part design structure with, on the one hand, a control unit or base unit and on the other hand a dispensing unit, which can be installed in a receiving- or holding device of the base unit in such a way that the dispensing unit can easily be taken out and exchanged. The dispensing unit, which contains a supply of the substance to be dispensed, includes at least a dispensing head with a discharge orifice and with component elements that serve to open and close the discharge orifice, as well as in certain cases to propel and loosen the powderous or pasteous dosage material. As a further constituent part of the dispensing unit, a source container can be connected to the dispensing head for the purpose of accommodating a bigger supply volume. 
         [0005]    The control unit in the dosage-dispensing device of EP 1930702 A1 is a stationary base- or console unit which is set up on a work surface. In the operating state, the discharge orifice of the installed dispensing unit is directed downward, and the means for opening and closing the discharge orifice as well as, in certain cases, for propelling and loosening the powderous or pasteous dosage material are in releasable engagement with propulsion- or actuation elements that are part of the control unit. The dispensing unit in its installed state in the control unit is arranged in a laterally projecting part of the control unit, so as to provide space for a balance below the dispensing unit. For further details, the reader is referred to the European patent application EP 1930702 A1, whose disclosure content in its entirety is hereby incorporated by reference in the present description. 
         [0006]    In the dosage-dispensing device described in EP 1930702 A1, the functions of advancing and loosening the powderous or pasteous dosage material are performed through the stirring action of a stirring mechanism in the dispensing head and, in certain cases, a second stirring mechanism in the source container. A further dosage-dispensing device, which is described in commonly-owned EP 1959244 B1 (also available as U.S. Pat. No. 8,191,587 B2), shows the same design structure with a base unit on which an exchangeable dispensing unit is installed. However, the functions of propelling and loosening the dosage material are in this case achieved by imparting shocks to the dispensing unit. The control unit is equipped for this purpose with an impact mechanism, i.e. in essence a hammer mechanism. This solution proves to be particularly advantageous for certain powderous dosage materials such as for example corn starch, which would be compacted by stirring instead of being loosened, so that the flow of material through the dispensing head would be blocked and, as a consequence, no material could be discharged from the dispensing head even with the discharge orifice fully opened. For further details of this dosage-dispensing device with an impact mechanism, the reader is referred to EP 1959244 B2, which is hereby incorporated by reference as if fully recited herein. 
         [0007]    Further details and variations of the state of the art, specifically in regard to the dispensing head, can be found in commonly-owned EP 2088404 A1 (also available as U.S. Pat. No. 8,281,959 B2). Among other things, a dispensing head is described wherein the area of the discharge orifice consists of an elastic material, so that the for example slit-shaped orifice can be spread apart through mechanical action, and closed again by removing the mechanical action. In addition, different embodiments of propelling means are presented, as well as designs of the inside which complement the propelling means. 
         [0008]    All of the examples of the state of the art named above are characterized by the aforementioned two-part structure with a base/control unit and a dispensing unit that can be installed in the base unit. The ease of installing and removing or exchanging the dispensing unit is a particularly important aspect. A receiving device which is connected to the base unit and in which the dispensing unit can be seated and safely secured is described in commonly-owned EP 1959243 B1 (also available as U.S. Pat. No. 8042711 B2). 
         [0009]    In each of the dosage-dispensing devices of the state of the art the dispensing unit, which can include the dispensing head by itself or a dispensing head with an attached source container, is designed for long-term, repetitive use, i.e. as a unit which can be refilled again and again with the same or a different dosage substance and which can also be cleaned in between. 
         [0010]    In practice, however, a still unmet need has been discovered for a favorably priced, compact dispensing unit, preferably consisting of the dispensing head alone, which can be used, for example, for a small number of dispensing cycles with the same substance and which can subsequently be discarded with the left-over substance remaining inside it. A dispensing unit of this kind offers strong advantages in particular for the dispensing of toxic substances. 
         [0011]    It is therefore the object of this invention to provide a dispensing head which can be used as part of a dosage-dispensing device of the kind described for example in EP 1930702 A1 for the dispensing of free-flowing powderous and pasteous substances. The dispensing head should be configured in particular for small fill quantities (typically less than two grams), and its manufacturing cost should be low enough that it could be discarded after use as a consumable supply article. 
       SUMMARY 
       [0012]    This task is solved by a dispensing head with the features according to the independent main claim  1 . Further configurations and embodiments of the subject of the invention are presented in the subordinate claims. 
         [0013]    A dosage-dispensing head for the dispensing of free-flowing dosage material includes a housing with an interior space to receive the dosage material, a fill opening and a discharge orifice, as well as a shutter bolt arranged in the housing, wherein the shutter bolt is movable in the direction of a shutter bolt axis and rotatable about said shutter bolt axis to perform the functions of opening and closing the discharge orifice and of loosening and advancing the dosage material. In particular, the dispensing head can take on a dispensing position and a fill position that is different from the dispensing position, wherein in the fill position the dosage material can be filled in through the fill opening, and in the dispensing position it can be dispensed through the discharge orifice. In the dispensing position, where the orientation of the shutter bolt is essentially vertical and the discharge orifice is at the bottom end of the dispensing head, the fill opening is positioned laterally on the housing in an essentially vertical orientation. The dispensing head further has a likewise laterally arranged rest surface diametrically opposite the fill opening for the purpose that the dispensing head in the fill position, which is essentially tilted 90° from the dispensing position and thus horizontally oriented with the fill opening on top, can be stably seated on a work surface. The dispensing head further includes a cap to close the fill opening. 
         [0014]    In comparison to the dosage-dispensing units and dispensing heads of the state of the art, the arrangement according to the invention with the lateral fill opening and the diametrically opposite rest surface provides a particularly convenient way to fill and, if desired, to store the dispensing head, as the feature of the rest surface allows the filled dispensing heads to be stored or also to be set aside only temporarily without the need for special racks or holders. 
         [0015]    Advantageously, a clutch is arranged at the upper end of the shutter bolt (relative to the dispensing position), through which a drive shaft of a control unit can be releasably engaged to drive the axial displacement and rotation of the shutter bolt. 
         [0016]    The dispensing head of the invention preferably includes a snap connection between the cap and the housing, whereby in the closed state the cap can be secured in the fill opening. 
         [0017]    In advantageous embodiments, the fill opening and the cap preferably have smoothly curved mutually fitting contours of an, e.g., round or in particular elliptical shape. In comparison to an, e.g., rectangular shape of the cap and the fill opening, this makes it easier for the cap to snap into the fill opening. The elliptical contour of the cap and the fill opening is preferred over a circular shape, because it necessarily dictates a certain orientation for setting the cap in place. An elliptical contour has the advantage that the fill opening, while compatible with the rectangular exterior surface, is large and thus facilitates the filling operation, while the contour is free of corners, with a smooth, unbroken perimeter. The longer axis of the ellipse is oriented essentially in the direction of the longer side of the substantially rectangular outside surface of the dispensing head. 
         [0018]    The interior cavity of the dispensing head preferably has a cylindrical inside wall, at least in the area of the fill opening, and the inside of the cap, which in the closed state faces towards the interior cavity, is preferably also of cylindrical shape with a flush transition to the interior wall. This design is particularly advantageous in that it avoids edges, gaps and other irregularities in the interior cavity of the dispensing head, where dosage material could accumulate during the dispensing process. 
         [0019]    The housing in advantageous embodiments of the dispensing head has a recess on the same side as the fill opening, which serves as a seat for the cap where the latter could be set aside during time periods when the cap is not covering the fill opening, i.e. for example during the filling process or also on an empty dispensing head in either factory-fresh or cleaned condition. After the filling has been completed, the cap is taken out of the recess, set into the fill opening to close up the latter, and securely snapped into place. Only now is the dispensing head turned upright from the fill position into the dispensing position and installed in the base unit of a dosage-dispensing device. 
         [0020]    The dosage-dispensing head can further have a seat for a means of identification, for example an RFID transponder, on which data are stored concerning the dosage substance contained in the dispensing unit. As a practical consideration, the seat is designed so that the means of identification can be attached to, or removed from, the housing without a tool. 
         [0021]    In preferred embodiments of the dispensing head at least one stirrer element is formed on the shutter bolt, which serves to loosen up the dosage material and to prevent the formation of lumps. 
         [0022]    The housing of the dosage-dispensing head is preferably configured with a two-part design structure, wherein a first housing part and a second housing part can be joined together by means of a form-locking connection and without the need for a tool. The form-locking connection between the first and the second housing part is preferably designed as a snap connection. 
         [0023]    The upper end (relative to the dispensing position) of the shutter bolt carries a preferably cylindrical shutter bolt cap as a guide for centered movement in an axial passage opening of the dispensing head. The shutter bolt cap is preferably designed to be slid over the the upper end of the shutter bolt and to be attached to the latter through a form-locking snap connection. 
         [0024]    The dosage-dispensing head according to the invention contains a return spring which is preferably arranged so that a lower end of the return spring (relative to the dispensing position) is braced against the second housing part and an upper end bears against the shutter bolt cap so that the pre-tensioning force of the return spring pushes the shutter bolt into a rest position which is defined by an axial end stop of the shutter bolt, whereby the dosage-dispensing head is closed up. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    Details of the dosage-dispensing head of the invention are explained in the description of the examples that are illustrated in the drawings, wherein: 
           [0026]      FIG. 1  shows an exploded view of a dosage-dispensing head according to the invention; 
           [0027]      FIG. 2  shows the dosage-dispensing head of  FIG. 1  with the view directed at the fill opening; 
           [0028]      FIG. 3  shows the dosage-dispensing head of  FIG. 1  with the view directed at the rest surface; 
           [0029]      FIG. 4  shows the dosage-dispensing head of  FIG. 1  in a sectional view in the plane of the shutter bolt axis; 
           [0030]      FIG. 5  shows a dosage-dispensing device with the dosage-dispensing head according to the invention; 
           [0031]      FIG. 6  shows the cap of the fill opening of a dosage-dispensing head according to the invention in different views; and 
           [0032]      FIG. 7  shows the dosage-dispensing head of  FIG. 1  with an optional source container attached. 
       
    
    
     DETAILED DESCRIPTION 
       [0033]      FIG. 1  shows an exploded view of a preferred embodiment of the dosage-dispensing head  5  according to the invention. The two-part design structure of the housing  3  is evident with a first, lower housing part  50  (relative to the dispensing position) and a second, upper part  60 . The first housing part  50  includes the discharge orifice  62  which, in the dispensing position, is located at the lower end, as well as the laterally arranged and essentially vertical fill opening  57  which can be closed up with the cap  90 . A snap connection is used advantageously to keep the cap  90  securely seated in the fill opening  57 . Further, insertion guides  55  are arranged on the first housing part  50  on either side of the fill opening. To join the first and second housing parts  50 ,  60  together, the insertion guides  55  are set into the guide grooves  65  of the upper, second housing part  60 , whereby an exact alignment of the two housing parts  50  and  60  is achieved. The second housing part  60 , on the side which in  FIG. 1  faces the viewer, has a recess  52  in which the cap  90  can be kept when it is not seated in the fill opening  57 , i.e. for example during transport or during the filling process, or also on an empty dispensing head in either factory-fresh or cleaned condition. 
         [0034]      FIG. 1  further shows the shutter bolt  80  which, in the operating state of the dosage-dispensing head  5 , is rotatable about the shutter bolt axis  81  as well as movable up and down in the direction of the shutter bolt axis  81 . The further details of the shutter bolt  80  that are identified by reference symbols in  FIG. 1 , as well as the return spring  100 , the shutter bolt cap  70  and the means of identification  4  will be explained in the context of the following  FIGS. 2 to 4 . 
         [0035]      FIG. 2  shows the dosage-dispensing head  5  of  FIG. 1  with the housing parts  50  and  60  in the assembled state in dispensing position, with the view directed at the fill opening  57  which is closed by the cap  90 . Located above the closed fill opening  57  is the recess  52  which serves as a seat, where the cap  90  can be kept and advantageously secured by an easily releasable snap connection. In  FIGS. 2 and 3 , on the upward-facing side of the dosage-dispensing head  5 , the shutter bolt cap  70  can be seen which is attached to the shutter bolt  80  by a snap connection. The upward-facing end of the shutter bolt  80  which appears at the center of the shutter bolt cap  70  is configured as a clutch  85 , whereby a drive shaft  11  of a dosage-dispensing device  1  (see  FIG. 5 ) can be brought into a releasable engagement with the shutter bolt  80  to drive the axial and rotary movements of the latter. 
         [0036]      FIG. 3  shows the dosage-dispensing head  5  from the opposite side which faces away from the fill opening  57  and whose entire border area is designed as a rest surface  51  which, as already described, serves the purpose that in the fill position, i.e. when the dosage-dispensing head  5  is essentially tilted by 90° from the dispensing position, with the fill opening  57  on top and oriented horizontally, it can be stably positioned on a work surface. A recess  58  that is surrounded by the rest surface  51 , contains a seat  64  of a means of identification  4  which can exist, e.g., of an RFID transponder. Also shown in  FIG. 3  is an electrical contact pad  53  which serves to drain electrostatic charges which, during operation, can build up in the plastic material that the dosage-dispensing head  5  is made of and which, due to electrostatic cohesion, can impede the discharge of the dosage material from the dosage-dispensing head. The first housing part  50  in the illustrated embodiment is predominantly cylindrical and, in its lowest portion, conically tapered towards the discharge orifice  62 . Arranged at the transition from the cylindrical to the conical shape is a border ring  54  which serves a sealing function when the conical part of the dosage-dispensing head is set into a corresponding circular opening in the top panel of a draft shield housing (not shown in the drawings), in which a target vessel for the dispensed substance is located. 
         [0037]    The sectional view of  FIG. 4  illustrates in particular the arrangement of the shutter bolt  80  in the dosage-dispensing head  5 . When the dispensing head  5  is being assembled from its individual parts  50 ,  60 ,  70 ,  80 ,  90 ,  100 , the first step is to insert the shutter bolt  80  from below (relative to  FIG. 4 ) into the axial passage opening  66  of the second housing part  60 , to the point where the stop  83  of the shutter bolt  80  rests against the shoulder  68  of the passage opening  66 . Next, the return spring  100  is slid over the shutter bolt  80  from the upper end of the axial passage opening  66  and pushed home against the bottom of the ring-shaped seating groove  69 . The shutter bolt cap  70  is slid over the shutter bolt  80  and the return spring  100 , thereby compressing the latter, and by snap engagement with the circular groove  86 , the shutter bolt cap  70  is locked to the shutter bolt  80 . The first housing part  50  is set into the second housing part  60  and snapped securely into position. The cap  90  is set into the recess  52  of the second housing part, where it is held by an easily releasable snap connection until the dispensing head is put into operation. Likewise in the assembly process of the dosage-dispensing head  5 , a means of identification  4 , for example an RFID transponder unit, can be installed in the recess  58 . Configured as a projection on the right side (in  FIG. 4 ) of the first housing part  50 , the contact pad  53 , through electrical contact with the dosage-dispensing apparatus  1  (see  FIG. 5 ) serves to drain electrostatic charges from the first housing part  50  into the electrically grounded dosage-dispensing apparatus  1 . For this drainage of charges to take place, it is intended to produce the first housing part  50  with the contact pad  53  of an electrically conductive material. Advantageously, the contact pad consists of an electrically conductive polymer. 
         [0038]    When the dosage-dispensing head  5  is in its rest position as shown in  FIG. 4 , the stop  83  of the shutter bolt  80 , under the pre-tensioning force of the return spring  100 , is pushed against the shoulder  68  at the bottom end of the axial passage opening  66 , so that the shutter bolt cap  70  at the upper end (in  FIG. 4 ) of the shutter bolt  80  is flush with the level of the top surface of the dispensing head  5 , while the lower end of the shutter bolt  80  fills out, and thereby blocks, the discharge orifice  62 . 
         [0039]    The function of the shutter bolt  80  can be explained by means of  FIGS. 4 and 5 . To perform a dispensing process, a filled dispensing head  5  is set into the holder device  10  of a dosage-dispensing device  1  ( FIG. 5 ). Typically, a target vessel (not shown in the drawing) will be placed on a balance below the dosage-dispensing head  5 . In the dispensing process, which is in most cases controlled automatically, the drive shaft  11  which can rotate about its axis and in certain cases simultaneously perform a vertically pulsating knocking movement is lowered to the dispensing head  5  and brought into engagement with the clutch  85  of the shutter bolt  80 . When fully engaged, the drive shaft  11  pushes the shutter bolt  80  further in the downward direction against the biasing force of the return spring  100 , while the rotation and, if applicable, the superimposed axial knocking movement of the drive shaft  11  are transmitted to the shutter bolt  80 . With the downward displacement of the cutback  82 , a variable, controllable portion of the aperture cross-section of the discharge orifice is set free for the passage of dosage material. Simultaneously, the dosage material in the interior space  59  of the first housing part  50  is loosened and propelled towards the discharge orifice  62  by the rotation and, if applicable, the additional axial knocking movement of at least one stirrer element  84  which is formed on the shutter bolt  80 . In particular with the maximally possible downward displacement of the shutter bolt, which is delimited by the step  67  of the second housing part  60  stopping the shutter bolt cap  70 , the outside edge  87  of the stirrer element  84  which conforms to the interior wall contour is sweeping the latter in the vicinity of the discharge orifice  62 , whereby dosage material that is present in this zone is swept off and moved towards the discharge orifice  62 . 
         [0040]      FIG. 6  shows the cap  90  of the fill opening in three normal projections and in a perspective view. Two indentations  92 , one of which is visible in the drawing, serve to hold the cap  90  in the recess  52  through their easily releasable snap engagement with projections of complementary shape in the recess  52 . In the fill opening  57 , on the other hand, the cap  90  is fastened and sealed along it entire circumference. This fastening and sealing connection can be achieved for example with a ridge  95  (see  FIG. 4 ) which runs along the inside circumference of the fill opening  57  and snaps into a correspondingly shaped set-back  96  along the outside edge of the cap  90 . The cylindrical inside surface  91  of the cap is shaped so as to fit into the cylindrical wall of the interior space  59  with a practically break-free transition. 
         [0041]      FIG. 7  again shows the dosage-dispensing head  5  of  FIG. 1 , but instead of the cap  90  an adapter  93  is installed in the fill opening  57 , allowing a source container  94  to be connected to the dispensing head  5 . As the cap  90  is not used in this case, it remains in the recess  52 . 
         [0042]    Although the invention has been described through the presentation of specific examples, it will be evident to the reader that numerous further variant embodiments could be developed from the teachings of the present invention, for example by combining the features of the individual embodiments with each other or by interchanging individual functional units of the individual embodiments against each other.