Dosing apparatus with a joint arrangement

[0001] This application is a §371 national stage entry of PCT International Application No. PCT/IB2010/051883 filed Apr. 29, 2010. PCT/IB2010/051883 claims priority to IT Application No. BO2009A000282 filed May 8, 2009. The entire contents of these applications are incorporated herein by reference.

[0002] The present invention relates to a dosing apparatus, in particular a volumetric dosing apparatus of the piston-cylinder type, which is associated with automatic filling machines for dosing determined and precise quantities of liquid.

[0003] In the pharmaceutical, cosmetic and food fields the use of volumetric piston pumps is known that are installed on filling machines for dosing or metering fluid products with variable viscosity in containers, such as bottles, miniature bottles, vials and the like.

[0004] In such devices, which are also called dosing pumps or syringes, a piston moves linearly with a reciprocating motion inside a dosing chamber made in a hollow, tubular cylinder. The piston stroke enables a defined volume of liquid product to be drawn and subsequently dispensed, the volume being a function of the stroke and of the diameter of the dosing chamber. The product to be dosed enters and exits the dosing chamber respectively through an inlet and outlet opening. The inlet opening is connected to a supply conduit connected to a tank of the product, whereas the outlet opening is connected to a delivery conduit connected, for example, to nozzles or cannulas for dosing the product in the containers.

[0005] External shut-off valves are provided on the supply and delivery conduits to alternately close and/or open the latter during syringe operation.

[0006] Some dosing syringes that replace external valves include a switching device that is placed inside the dosing chamber and is commanded so as to connect the latter alternatively to the supply and delivery conduits in phase with the rectilinear movement of the piston. Such switching device may consist of a rotating valve inserted inside the dosing chamber, that is able to open and close the inlet and outlet openings.

[0007] Alternatively, dosing syringes are known in which the switching device is formed on the piston and referred to as a valve-piston. In this case, the piston, in addition to sliding axially, can rotate about its longitudinal axis by a preset angle, in order to place the dosing chamber alternately in communication with the supply conduit and with the delivery conduit.

[0008] In dosing syringes, especially in the pharmaceutical field, the precision of the piston stroke is essential for the precision and accuracy of the dose.

[0009] Similarly, precision in rotating the valve piston is necessary to ensure correct suction and delivery of the product to be dosed.

[0010] In a dosing syringe provided with a separate rotating valve and piston, the cylinder is open at both ends to enable the piston and the valve to be connected to distinct driving members that provide alternating linear movement and rotation, respectively.

[0011] In dosing syringes provided with a valve piston, a top or bottom end portion of the valve piston is connected to driving members that both rotate and move the piston linearly.

[0012] Known filling machines include supporting frames that support a plurality of dosing syringes and, if provided, support the respective driving members of the pistons and/or valves.

[0013] The supporting frames include shaped seats inside which the dosing syringes are insertible and removably lockable, typically by fixing brackets that are fastened to the frame by screws or by quick connections of the tri-clamp type.

[0014] Known supporting frames ensure precise and firm support of the dosing devices but impose laborious and complex assembly and dismantling procedures that may also require the use of two operators. Such procedures are even more complex and inconvenient if the dosing syringes are associated with filling machines operating in an aseptic or sterile environment and thus filling machines are provided with housings that enable the processing zone to be accessed in which packaging of the product occurs only through openings provided with gloves (“gloveports”).

[0015] When the driving members are arranged above the syringes they are housed inside suitable containing casings or housing as they include motors, transmission and kinematic mechanisms, sensors, etc. that for reasons of cleanliness and hygiene have to be separated from the process zone.

[0016] The dimensions and the position of the aforementioned housings nevertheless have some drawbacks, which include a reduction in the accessibility to the process zone and to the operating devices located within the process zone, should the need arise to access the interior of the process zone (compromising the sterility thereof) in the event of failure or breakage of the aforementioned mechanical members and components to permit maintenance tasks to be performed. In addition, if the sterile and/or aseptic process zone is subject to a flow of sterile air, the dimensions and position of the aforementioned housings cause the airflow to be deviated or altered at the dosing zone increasing the risk that movement of dosing syringe pistons may generate particles that may be dragged by the airflow inside the housings below, contaminating the containers.

[0017] In order to overcome such drawbacks, particularly in the packaging of pharmaceutical products, the current trend is to have dosing syringes that are rotated and moved rectilinearly from the bottom so as to have corresponding movement members located inside a base of the filling machine.

[0018] For this purpose, a drive shaft exits the base of the filling machine and is removably connected to a lower end of the piston of the syringe by a joint of prismatic type that provides the necessary precision in the transmission of linear motion and rotation and at the same time enables the syringe to be assembled and dismantled.

[0019] In particular the joint typically includes a T-shaped element, fixed to the end of the piston and housed in a seat with a complementary shape that is obtained on an upper end of the drive shaft. The T-shaped element can slide transversely inside the seat, typically perpendicularly, to the movement direction of the piston. In this manner, the T-shaped element can be inserted and detached from the seat, respectively, to connect or disconnect the syringe to or from the movement members. Nevertheless, in order to enable the T-shaped element to be removed from the seat in any operating position of the piston, the stem of the latter has to be of a length that is such as to enable the lower end thereof to always remain outside the cylinder.

[0020] Owing to the considerable length of the pistons, such dosing syringes are bulky and difficult to handle, assemble, and dismantle. Also, the dimensions and the space requirements of the supporting frames that are necessary for supporting the dosing devices are significant and considerably limit accessibility to the processing zone of the filling machine.

[0021] Known dosing devices are generally made of stainless steel, a material that is suitable for contact with pharmaceutical and/or food products and which can undergo cleaning and sterilizing procedures.

[0022] Further, it is known to use ceramic materials owing to which it is possible to make components that have narrow dimensional tolerances and reduced surface roughness values.

[0023] Ceramic materials have very high coefficients of resistance to wear and to high temperatures and extremely moderate thermal expansion coefficients. These features make ceramic materials particularly suitable for making high-precision piston pumps that are set up for cleaning and sterilizing-in-place operations.

[0024] Ceramic materials nevertheless have limits in the mechanical field, inasmuch as they are relatively fragile, easily subject to breakage, fractures and splintering.

[0025] For this reason, the cylinders of pumps made of ceramic material are covered by a metal liner, typically made of stainless steel. The latter is hot-mounted through interference in such a manner as to form a single monolith body with the ceramic cylinder.

[0026] The external metal casing, in addition to protecting the ceramic internal cylinder, enables the syringe to be fixed to the supporting frame and the fittings of the supply and delivery conduits to be connected thereto.

[0027] In many applications, especially in the pharmaceutical field and in the foodstuffs field, it is required that the dosing syringes be subjected to cleaning and sterilizing operations in place, without any component thereof needing to be dismantled. Such operations, which are known by the name of CIP/SIP (Cleaning In Place/Sterilizing In Place), include a sequence of steps that are performed automatically or semiautomatically, in the course of which the inner part of dosing syringes is traversed by cleaning liquids at different temperatures and by pressurised steam. In this manner, within a relatively short amount of time it is possible to clean and sterilize all the parts of the syringe that came into contact with the product.

[0028] An essential condition for the correct and valid performance of a cleaning and sterilizing operation is that each internal surface of the syringe that has been in contact with the product is appropriately subjected to the necessary flowing speed by the cleaning and sterilizing fluids.

[0029] In addition, the structure of the syringe has to ensure correct draining and emptying of such fluids at the end of the cleaning and sterilizing cycles, i.e. there are no zones in which the fluids can accumulate and stagnate. In particular, the dosing syringes set up for CIP/SIP operations include a cleaning and sterilizing chamber connected to and coaxial with the dosing chamber, and provided with an opening for the exit of the cleaning and sterilizing fluids. In one syringe cleaning and sterilizing configuration, the piston is positioned inside the cylinder, in such a manner that the portions thereof that come into contact with the product are spaced from the internal walls of the dosing chamber and of the cleaning and sterilizing chamber. In this manner, the aforementioned portions of the syringes and the internal walls of the entire dosing chamber can be reached by the cleaning and sterilizing fluids.

[0030] FR 2797046 illustrates a volumetric dosing device including a hollow body defining a dosing chamber, provided with a supply conduit and with a delivery conduit of the product to be dosed, and a piston that is movable linearly and in rotation inside the dosing chamber. The latter extends below in a secondary chamber, arranged for housing an extension of the piston and closed on the bottom by a closing element, removably connected to the hollow body and provided with a conduit for discharging the cleaning and sterilizing fluids. The device further includes a cleaning and sterilizing chamber placed above the dosing chamber and provided with an inlet conduit for the cleaning and sterilizing fluids. The cleaning chamber includes a cylindrical tubular element removably connected to the hollow body and provided with a gap connected to the inlet conduit and separated from the cleaning and sterilizing chamber by a cylindrical baffle provided with transverse holes.

[0031] One drawback of such a dosing device is the complex, bulky and costly structure thereof, this structure including, among other things, four distinct conduits for the entry and exit, respectively, of the product to be dosed and of the cleaning and sterilizing fluids.

[0032] WO 2004027352 discloses a volumetric dosing device including a hollow body defining a dosing chamber, provided laterally with a supply conduit of the product to be dosed, and a piston that is movable linearly and in rotation inside the dosing chamber. The latter is closed by a closing element removably connected to the first hollow body and provided with a delivery conduit of the product to be dosed. A further hollow body, connected to a lower end of the hollow body, forms a cleaning and sterilizing chamber provided at the bottom of a discharge conduit of the cleaning and sterilizing fluids.

[0033] The aforementioned dosing syringe has a more compact and simpler structure than the syringe illustrated in FR 2797046, but is more demanding and laborious to handle as the piston may accidentally exit from the hollow bodies, during transport, thus becoming damaged and/or soiled.

[0034] Both the dosing devices discussed above include a plurality of components (hollow bodies, closing elements) that are removably connected to one another and can nevertheless have cleaning and sterilizing problems. In fact, it is possible that, owing to imprecision in the machining of the components and/or non-optimum coupling between components, in the interface or connecting zones of the latter there are slits or interstices of dimensions that permit infiltration and diffusion of the product to be dosed and/or of the cleaning and sterilizing fluids. In this case, in order to perform correct and complete cleaning of the syringe, it is necessary to completely dismantle the latter, thus increasing operating time and consequently increasing running costs.

[0035] Another drawback of the dosing devices disclosed above lies in the complex and delicate manual procedures that are necessary for correctly assembling the syringes and subsequently mounting the syringes on the filling machine. Such procedures require specialized and costly personnel.

[0036] One object of the present invention is to improve known volumetric dosing devices, in particular dosing devices of the valve piston type that are associated with filling machines.

[0037] Another object is to make a dosing device including a dosing unit which is automatically connected to or disconnected from a piston driving device provided in the filling machine, without requiring manual intervention of an operator and regardless of the operating position of the aforementioned piston.

[0038] A further object is to make a dosing device including a joint that is able to connect or disconnect the piston quickly and automatically to and from the corresponding movement mechanism and the joint at the same time ensuring precise and accurate transmission of the linear motion and rotation motion to the aforementioned piston.

[0039] Still another object is to make a dosing device including a supporting and locking device, associated with the filling machine that enables the dosing unit to be assembled and dismantled easily and quickly, while ensuring precise and firm positioning of the dosing unit in a mounting operating configuration.

[0040] A still further object is to provide a dosing unit that is able to dose with great precision and accuracy quantities of liquid in desired volumes and is further set up for cleaning and sterilizing-in-place (CIP/SIP) operations.

[0041] Another object is to make a dosing unit that has a particularly simple and compact structure and is at the same time tough and resistant to blows.

[0042] Still another object is to make a dosing unit that requires minimal and simple manual procedures for assembling and/or mounting the dosing unit on a supporting and locking device.

[0043] Owing to the dosing apparatus of the invention it is possible to connect or disconnect a piston of a dosing unit to/from a movement mechanism without having the end portion of the piston protrude outside the dosing unit. In particular, the end portion can always be contained, in any operating position, inside a cavity of the dosing unit.

[0044] This enables the length of the piston to be reduced and allows a dosing unit to be made that has a compact longitudinal dimension. Such an arrangement is particularly suitable for use in filling machines that require ample accessibility to the processing zone.

[0045] The piston is further connectable to or detachable from the movement mechanism in a completely automatic manner, without requiring manual intervention of an operator and thus reduces downtime and mounting errors.

[0060] With reference to FIGS. 1 to 7, there is illustrated a dosing apparatus 1 that is associated with a filling machine and including a dosing unit 2 that includes a piston 3 that is movable along a first longitudinal axis W1 in a cavity 4 of a casing or housing 5 to draw a desired quantity of liquid from an inlet 82 of the casing 5 and direct the quantity of liquid to an outlet 83 of the casing 5.

[0061] The apparatus 1 includes a supporting device 40 that is, for example, secured to an external wall 102a of a base 102 of the filling machine and arranged for supporting and locking the dosing unit 2 in a mounting configuration A.

[0062] The apparatus 1 also includes a joint 10 for removably connecting, in the mounting configuration A of the dosing unit 2, a first end portion 6 of the piston 3 to a movement or drive mechanism 101 arranged for moving the piston 3 linearly and rotationally.

[0063] The movement mechanism 101, which is of known type and is not illustrated in detail in the figures, is contained inside the base 102 of the filling machine.

[0064] With reference to the embodiment illustrated in the figures, the first end portion 6 of the piston 3 is the lower end portion, the dosing unit 2 thus being driven from the bottom by the movement mechanism 101.

[0065] The piston 3 is of the valve-piston type and includes a second end portion 7 that is opposite the first end portion 6, is slidable inside the cavity 4 and provided with a switching device 9 that connects the cavity 4 to the inlet 82 or to the outlet 83.

[0066] The piston 3 driven by the movement mechanism 101 is movable by reciprocating linear movement along the first axis W1 between a retracted or internal position and an extended or external position, and is movable around the first axis W1 with a rotating movement that is also reciprocating, between a suction position in which the switching device 9 connects the cavity 4 to the inlet 82 and a delivery position, in which it connects the cavity 4 to the outlet 83.

[0067] The casing 5 of the dosing unit 2 includes an internal tubular element 51, with a substantially cylindrical shape which contains the cavity 4, and an external covering element 52 that envelops the internal tubular element 51 and extends to an end, for example a lower end, of the latter in such a manner as to form a further cavity 53 provided with a respective opening 56 for the passage of the joint 10.

[0068] The internal tubular element 51 is made, for example, of ceramic material, whereas the covering element 52 is made of synthetic plastics. In particular, the covering element 52 is moulded directly around the internal tubular element 51 by injection molding in such a manner as to form a single body with the latter.

[0069] The covering element 51 further includes a handle-shaped gripping portion 52a, to enable the dosing unit 2 to be easily gripped and handled by an operator, particularly during a mounting/dismantling step as explained in detail below.

[0070] The cavity 4, which has a substantially cylindrical shape and extends longitudinally for the entire length of the internal tubular element 51, includes a lower dosing chamber 4a and an upper dosing chamber 4b that have different diameters and lengths. In particular, the lower dosing chamber 4a has a greater diameter than that of the upper dosing chamber 4b.

[0071] The upper dosing chamber 4b is flowingly connected via the inlet 82 to a circuit supplying the product to be dosed, the inlet 82 including a conduit made on side walls of the tubular element 51 and of the covering element 52 and being transverse, in particular almost orthogonal to the first axis W1. The upper dosing chamber 4b is further flowingly connected to a delivery circuit of the product via the outlet 83, including a respective conduit, for example made on a top portion 52b of the covering element 52, which closes the cavity 4 above, the respective conduit being substantially coaxial with the first longitudinal axis W1.

[0072] The inlet 82 and the outlet 83 are provided externally with fittings 82a, 83a for quick connection to the supply and delivery circuits, for example Tri-clamp quick connections. The fittings 82a, 83a are made directly on the covering element 52.

[0073] The dosing unit 2 of the invention is set up for cleaning and sterilizing CIP/SIP operations. Such operations, which do not require any component of the dosing unit 2 to be dismantled, include a sequence of steps that can be performed automatically or semiautomatically, in the course of which the inside of the unit is traversed by cleaning liquids at different temperatures and by pressurized steam.

[0074] For this purpose, the covering element 52 extends below the tubular element 51 in such a manner that a lower cylindrical portion 52c forms the further cavity 53 that acts as a cleaning and sterilizing chamber in a CIP/SIP operating step of the dosing unit 2. The further cavity 53 has a substantially cylindrical shape and has a diameter that is greater than that of the lower dosing chamber 4a. The further cavity 53 is flowingly connected to an external drainage circuit of the cleaning and sterilizing fluids via a further outlet 54, including a cleaning conduit, provided with a corresponding fitting 54a for quick connections.

[0075] The piston 3 includes an elongated cylindrical body that includes an intermediate portion 8 between the first end portion 6 and the second end portion 7, the portions being among themselves coaxial to the first longitudinal axis W1 and having different diameters and lengths.

[0076] The intermediate portion 8 is arranged for sealingly sliding inside the lower dosing chamber 4a, whereas the second end portion 7 is arranged for sealingly sliding in the upper dosing chamber 4b.

[0077] The first end portion 6 slides with clearance inside the further cavity 53.

[0078] In a cleaning and sterilizing configuration L, the piston 3 is arranged in such a manner as to connect the cavity 4 in a flow connection to the further cavity 53 and to the further outlet 54. In particular, in the cleaning and sterilizing configuration L, the second end portion 7 and the intermediate portion 8 of the piston 3 are contained respectively completely inside the lower dosing chamber 4a and the further cavity 53, whereas the first end portion 6 of the piston 3, partially contained inside the further chamber 53, shuts the opening 56 of the further cavity 53. More precisely, an external side wall 6a of the first end portion 6 sealingly abuts on a seal 55, including for example an annular seal of the O-ring type and provided in a respective internal wall of the further cavity 53 in such a manner as to provide a flow connection between the latter and the external environment (FIG. 13). In this manner a cleaning and/or sterilizing fluid delivered inside the cavity 4 through the inlet 82 and/or the outlet 83 can reach and lap with the necessary speed all the points of the dosing chambers 4a, 4b and of the piston 3 that have come into contact with the product to be dosed.

[0079] It should be noted that owing to the structure and the embodiment of the dosing unit 2 of the invention, in the interface or coupling zones between the covering element 52 and the internal tubular element 51 the presence of slits, interstices or the like is excluded in which the product to be dosed, or the cleaning and sterilizing fluids, may become deposited, making the CIP/SIP operations ineffective or at least unacceptable.

[0080] The covering element 52 that is made of synthetic plastics therefore not only coats and protects the ceramic internal tubular element 51 from shocks and blows but also enables the dosing unit 2 to be fixed to the supporting device 40 and enables the supply and delivery circuits of the product to be dosed and drainage circuits of the cleaning and/or sterilizing fluids to be connected to the dosing unit 2 via the fittings 82a, 83a, 54a.

[0081] The first end portion 6 of the piston 3 includes a seat 16 configured for removably receiving a clutch portion 11 of the joint 10, the clutch portion 11 being connectable in, and disconnectable from, the seat 16 along a coupling direction T substantially parallel to the first axis W1.

[0082] The clutch portion 11 and the seat 16 have a complementary shape, for example a cylindrical shape, and dimensions such as to minimize residual radial clearance.

[0083] The joint 10 includes a connecting element 25, that includes the clutch portion 11, and a further connecting element 26 an end portion of which is connected to the movement mechanism 101. The connecting element 25 and the further connecting element 26 are rotatably connected by a spherical element 27.

[0084] The further connecting element 26 is moved by the movement mechanism 101 along and around a second axis W2. In use the joint 10 is normally assembled on the movement mechanism 101.

[0085] A locking device or assembly 12 is provided for reversibly fixing the clutch portion 11 of the first connecting element 25 in the seat 16. The locking device 12 includes one or more stop elements 13, for example two, associated with the clutch portion 11 and movable in such a manner as to engage or disengage respective housings or recesses 39 made in the seat 16 respectively to lock or release the first end portion 6 on or from the joint 10. An actuating device 14 acts on the stop elements 13 to push the latter inside the housings 39.

[0086] With reference to the embodiment illustrated in the figures, the stop elements 13 have a spherical shape and are inserted into openings 18, made opposite on a side wall 19 of the clutch portion 11, from which they are maintained protruding by the actuating device 14, housed in a gap 17 made inside the aforementioned clutch portion 11. The actuating device 14 includes an actuating devices such as a pressing element 15 that is slidable inside the gap 17 and provided with a tilted wall 15a acting on the stop elements 13.

[0087] The pressing element 15 defines with a bottom wall of the gap 17 a sealed lower chamber 21 to which a pressurized fluid, typically compressed air, is supplied. On the side opposite the lower chamber 21 there is provided an elastic element 22, for example a coil spring inserted into the aforesaid gap 17 and arranged in such a manner as to exert an elastic force that opposes the action exerted by the pressurized fluid.

[0088] The housings 39 are formed, for example, by an annular groove made on an internal wall of the seat 16 and shaped in such a manner as to receive the protruding portion of the stop elements 13.

[0089] In one coupling configuration B of the joint 10, the stop elements 13 pushed by the pressing element 15, which is in turn pushed by the spring 22, protrude from the openings 18 and engage the housings 39 in such a manner as to firmly lock the clutch portion 11 on the first end portion 6.

[0090] In particular, an annular end face 6b of the first end portion 6 abuts on an upper face 20a of an annular crown 20 of the clutch portion 11.

[0091] In a release configuration which is not shown, the pressing element 15 is moved by the pressurized fluid supplied to the lower chamber 21 to a position that is such as to enable the stop elements 13 to return inside the openings 18 such as to disengage the housings 39 and to enable the clutch portion 11 to be disengaged from the first end portion 6.

[0092] A transmission is provided for connecting the first end portion 6 to the clutch portion 11 such that the latter can transmit rotation torque.

[0093] The transmission includes at least one dowel 23 fixed to the clutch portion 11 and arranged for engaging in a further seat 24 obtained on the first end portion 6.

[0094] In particular, the dowel 23 is fixed to the upper face 20a of the annular crown 20 substantially parallel to the first axis W1 in such a manner as to be connected to or disconnected from the further seat 24 when the clutch portion 11 is respectively inserted into or detached from the seat 16.

[0095] The connecting element 25 includes a fork portion 35 opposite the clutch portion 11, whereas the further connecting element 26 includes a further fork portion 36 opposite the end portion fixed to the movement mechanism 101.

[0096] The fork portion 35 and the further fork portion 36 are rotatably connected by the spherical element 27. The fork portions 35, 36 include respective pairs of arms that partially enclose the spherical element 27, the pairs of arms being arranged on respective planes that are substantially orthogonal to one another.

[0097] The spherical element 27 permits corresponding rotation between the two connecting elements 25, 26, simultaneously ensuring the transmission of traction/compression force between the movement mechanism 101 and the piston 3, to ensure the reciprocating motion of the latter along the first axis W1.

[0098] The joint 10 further includes a sleeve 38 that surrounds and contains the fork portions 35, 36. The sleeve 38 is connected to the connecting elements 25, 26 by respective pins 29, 30.

[0099] In particular, a first pin 29 connects the sleeve 38 to the connecting element 25, whereas a second pin 30 connects the sleeve 38 to the further connecting element 26.

[0100] The first pin 29 and the second pin 30 have a cylindrical shape and are arranged substantially parallel and transversely to one another, in particular substantially orthogonally to the first axis W1.

[0101] The first pin 29 is fixed at respective opposite ends to the sleeve 38, for example by coupling through interference, whereas it is rotatably housed in a first through opening 31 of the connecting element 25. The first through opening 31 substantially includes a through slot, having a cross section that is shaped in such a manner as to leave the first pin 29 a radial clearance of a set amount only in a direction parallel to the first axis W1.

[0102] Similarly, the second pin 30 is fixed at respective opposite ends to the sleeve 38, for example by coupling through interference, whereas it is rotatably housed in a second through opening 32 of the further connecting element 26. The second through opening 32 has a cross section that is calibrated and substantially equivalent to that of the second pin 30 to enable the latter to rotate only around the respective longitudinal axis with almost zero radial clearance.

[0103] The sleeve 38, owing to the pins 29, 30 rotatingly connects the two connecting elements 25, 26 i.e. it is able to transmit rotation torque or twisting moment.

[0104] The joint 10 further includes a bellows element 33 that connects the clutch portion 11 of the connecting element 25 to an external wall 102a of the base 102 of the filling machine for enclosing and separating at least the fork portions 35, 36, the spherical element 27, the sleeve 38 and the pins 29, 30 from an external processing environment 80 in which dosing of the product occurs.

[0105] The joint 10 thus constitutes a constant-velocity joint that is able to transmit movement torque and an axial force with great precision between the movement mechanism 101 and the piston 3 even if the latter are not aligned.

[0106] As illustrated in FIGS. 6 and 7, the connecting elements 25, 26 rotatably connected by the spherical element 27, and the first pin 29 that is slidable in the first through seat 31 enable the joint 10 to operate even if the first axis W1 of the piston 3 is misaligned and/or tilted in relation to the second axis W2 of the further connecting element 26 owing, for example, to mounting and/or manufacturing imprecisions of the dosing unit 2 and/or of the supporting device 40.

[0107] In a mounting step, after an operator has fixed the dosing unit 2 to the supporting device 40 in the mounting configuration A, the movement mechanism 101 is activated in such a manner as to move the joint 10, that is mounted thereupon, along the second axis W2 until the clutch portion 11 is inserted inside the seat 16 of the first end portion 6.

[0108] By activating the locking device 12 in the coupling configuration B it is thus possible to lock the clutch portion 11 firmly on the first end portion 6, i.e. connect the piston 3 to the movement mechanism 101.

[0109] By performing the opposite operation, i.e. first deactivating the locking device 12, to disengage the stop elements 13 from the housings 39 of the seat 16 and by subsequently activating the movement mechanism 101, it is possible to disengage the clutch portion 11 from the seat 6, decoupling the piston 3 from the joint 10 and thus from the movement mechanism 10.

[0110] It should be noted that by virtue of the configuration of the joint 10 and of the piston 3 of the dosing apparatus 1 of the invention—which enables the clutch portion 11 to be inserted into and detached from the seat 16 of the first end portion 6 along a coupling direction T that is almost parallel to the first axis W1—it is possible to connect or disconnect the piston 3 to and from the movement mechanism 101 without any need for the first end portion 6 to be positioned outside of the casing 5. In particular, the first end portion 6 is always contained, in any operating position thereof, inside the further cavity 53 of the casing 5.

[0111] This enables the length of the piston 3 to be reduced and a dosing unit 2 to be made that has a compact longitudinal dimension and is thus particularly suitable for use in filling machines that require ample accessibility to the processing zone.

[0112] The piston 3 is further connectable to or detachable from the movement mechanism 101 via the joint 10, in a completely automatic manner, without requiring the manual intervention of an operator and thus reduces downtime and the risk of mounting errors.

[0113] FIGS. 8 to 11 illustrate a version of the dosing apparatus 1 that differs from the previously disclosed embodiment for the joint 110 that connects a first end portion 106 of the piston 103 to the movement mechanism 101.

[0114] The joint 110 includes a connecting element 125 with an elongated shape and provided at one end with a clutch portion 111 arranged for engaging in a seat 116 obtained in the first end portion 106. The remaining end of the connecting element 125 is on the other hand connected to the movement mechanism 101, such as to be linearly movable along and rotated around a second longitudinal axis W2.

[0115] Also in this case, the clutch portion 111 is connectable to and detachable from the seat 116 along the coupling direction T that is substantially parallel to the first axis W1 or tilted by a few degrees in relation to the first axis W1, as explained in greater detail below.

[0116] The clutch portion 111 and the seat 116 have a complementary shape, for example a frustoconical shape.

[0117] The joint 110 includes a locking device 112 arranged for reversibly locking the clutch portion 111 in the seat 116.

[0118] The locking device 112 includes a seal 113 fixed to an end of the clutch portion 111 and abutting on an internal wall of the seat 116. The seal 113 includes, for example, a ring seal made of elastomeric material housed in an annular cavity 132 formed in the end of the clutch portion 111. The end of the clutch portion 111, the seat 116 and seal 113 define an upper chamber 121 of the locking device 112 that is connected via a conduit 122, to a vacuum source such as a vacuum circuit. In one coupling configuration B, owing to the negative pressure or vacuum that is created in the upper chamber 121, the clutch portion 111 firmly engages the seat 116 with a connecting force the size of which depends on the shape and dimensions of the upper chamber 121 and on the vacuum values therein.

[0119] When the upper chamber 121 is returned to atmospheric pressure, for example by interrupting the connection with the vacuum circuit, the clutch portion 111 can be easily and smoothly detached from the seat 116 to enable the piston 103 to be detached from the movement mechanism 101.

[0120] An abutment assembly is provided for defining a reciprocal axial position along the first axis W1 between the first end portion 106 of the piston 103 and the clutch portion 111 of the connecting element 125, in the coupling configuration B.

[0121] The abutment assembly includes a first abutting pin 114 fixed to a bottom wall 116a of the seat 116 and a second abutting pin 115 fixed to the clutch portion 111. An intermediate element 126 that has a spherical shape and is elastically connected to the clutch portion 111 is interposed between the two abutting pins 114, 115.

[0122] In the coupling configuration B, the abutting pins 114, 115 contact the intermediate element 126 on opposite sides with a connecting force made by the upper chamber 121 placed under negative pressure. It should thus be noted that in the coupling configuration B there is zero axial clearance between the piston 103 and the connecting element 125.

[0123] The intermediate element 126 also acts as a shutter to close the connection between the upper chamber 121 or the outside environment and the conduit 122, when the clutch portion 111 is detached from the seat 106.

[0124] For this purpose, the clutch portion 111 includes a further gap 117 on the bottom of which is fixed the second abutting pin 115 and inside which is inserted the intermediate element 126. A further elastic element 118, for example a coil spring, envelops the second abutting pin 115 and acts on the intermediate element 126 so as to push the intermediate element 126 outside the further gap 117. In a release configuration in which the clutch portion 111 is detached from the seat 106, the further spring 118 pushes the intermediate element 126 to abut on an annular ridge 119 and an adjacent further seal 139 provided on a mouth portion of the further gap 117. In this position the abutting element 126 seals the further gap 117, connected via the conduit 122 to the vacuum source.

[0125] A transmission is provided for connecting the first end portion 106 on the clutch portion 111 such that the latter can transmit rotation torque.

[0126] The transmission includes one or more dowels 123, preferably two, spaced apart at an angle, for example 180°, fixed to a side wall 131 of the clutch portion 111 and arranged for engaging in corresponding further seats 124 obtained on the first end portion 106.

[0127] The dimensions of the dowels 123 and of the further seats 124 are such as to minimize radial clearance between the piston 103 and the connecting element 125 to ensure the necessary precision and accuracy in rotation motion during operation of the aforementioned piston 3.

[0128] The dowels 123 are fixed substantially perpendicularly to a longitudinal axis of the connecting element 125 in such a manner as to be inserted into or detached from the further seats 124 when the clutch portion 111 is inserted into or detached from the seat 106. The further seats 124 include respective slots that are open below.

[0129] The joint 110 includes a bellows element 133 that connects the clutch portion 111 of the connecting element 125 to an external wall 102a of the base 102 of the filling machine to close an opening for the passage of the connecting element 125, made in the external wall 102a, by the processing environment 80.

[0130] In the coupling configuration B of the joint 110, the seal 113 is crushed between the clutch portion 111 and the internal wall of the seat 116 by the connecting force generated by the negative pressure in the upper chamber 121. The elasticity and deformability of the seal 113 not only ensures the insulation of the upper chamber 121 from the external environment, but is able to transmit rotation torque or twisting moment between the connecting element 125 and the first end portion 106 of the piston 103 during normal operation of the dosing unit.

[0131] If the seal 113 slides in relation to the internal wall of the seat 116 or in relation to the annular cavity 132 of the clutch portion 111, the transmission, in particular the dowels 123 and the further seats 124, ensure correct angular positioning between the piston 103 and the connecting element 125 and correct transmission of the rotation torque.

[0132] As illustrated in FIGS. 10 and 11, owing to the elasticity and deformability of the seal 113, to the frustoconical shape of the clutch portion 111 and of the seat 106, and the radial clearance between the latter, the joint 110 is able to transmit to the piston 103 a linear and rotation movement in a precise and accurate manner, even if the first axis W1 and the second axis W2 are misaligned and/or tilted in relation to one another.

[0133] The joint 110 constitutes a constant-velocity joint that is able to transmit with great precision rotation torque and an axial force between the movement mechanism 101 and the piston 103 regardless of imprecision in the mounting and/or the manufacture of the dosing unit 2 and/or of the supporting device 40.

[0134] Also in this version of the dosing apparatus 1 it is possible to automatically connect and disconnect in a selective manner the piston 3 to/from the movement mechanism 101 without the manual intervention of an operator, with the first end portion 106 always arranged inside the casing 5 in any operating position.

[0135] With particular reference to FIGS. 1 to 3 and 12, the dosing apparatus 1 includes a coupling device 60 associated with the casing 5 and arranged for slidably engaging in a guide 41 of the supporting device 40 in the mounting configuration A of the dosing unit 2. The coupling device 60 is insertible into or detachable from the guide 41 along a first direction X, substantially parallel to the first longitudinal axis W1. The first direction X is, for example, vertical and substantially orthogonal to the upper wall 102a of the base 102 of the filling machine to which the supporting device 40 can be fixed.

[0136] In one version of the apparatus 1 that is not shown, the first direction X may be horizontal and substantially orthogonal to the first axis W1.

[0137] The supporting device 40 includes a supporting body 46 fixed to the upper wall 102a and supporting the guide 41. The latter includes a guiding element that has a flat shape and is provided with a rectilinear groove 49 that has an T-shaped cross section and extends parallel to the first direction X.

[0138] The coupling device 60 includes a T-shaped coupling element fixed to the casing 5 in such a manner as to slidably engage in the rectilinear groove 49 with a preset clearance to enable the dosing unit 2 to be easily mounted on and dismantled from the supporting device 40.

[0139] The coupling element 60 is provided directly on a side wall of the lower cylindrical portion 52c of the covering element 52.

[0140] Alternatively, the coupling element 60 can be a distinct element and be fixed to the aforesaid lateral wall of the lower cylindrical portion 52c.

[0141] The supporting device 40 further includes a fixture arranged for reversibly locking the coupling element 60 to the guide 41. The fixture includes at least two fixing elements 42, 43 associated with the guide 41 and movable in such a manner as to engage with or disengage from respective coupling notches 62, 63 of the coupling element 60, respectively, to lock or release the coupling device 60 to or from the guide 41.

[0142] A pushing device is provided for acting on the fixing elements 42, 43 and pushing the latter to abut on the coupling notches 62, 63 with a preset fixing force along a second direction Y, which is substantially orthogonal to the first direction X.

[0143] With reference to the embodiment illustrated in the figures, the fixture includes a first fixing element 42 and a second fixing element 43 that have a spherical shape and are inserted into a first opening 47 and into a second opening 48, respectively, aligned and superimposed on the first direction X in the guide 41. The first fixing element 42 and the second fixing element 43 protrude from the pushing device such as to engage a first coupling notch 62 and a second coupling notch 63, respectively, of the coupling element 60 in mounting configuration A.

[0144] The pushing device includes an actuating device, in particular a first actuator 44 and a second actuator 45, for example of pneumatic or mechanical type, connected to the first fixing element 42 and to the second fixing element 43, respectively. By activating the actuators 44, 45, it is possible to move the fixing elements 42, 43 alternately to a retracted position or to a protruding position, in which the fixing force is applied by the fixing elements 42, 43 to the coupling notches 62, 63. In an alternative embodiment that is not shown, the actuators 44, 45 can be replaced by an elastic device that is suitable for coupling with the fixing elements 42, 43.

[0145] The first opening 47 and the second opening 48 are provided with stopping portions that are not illustrated in the figures, to prevent the fixing elements 42, 43 from completely exiting from the openings 47, 48, i.e. to enable the latter to protrude by a preset amount.

[0146] The coupling notches 62, 63 have a spherical cap shape with a curvature radius that is less than the curvature radius of the fixing elements 42, 43 such that the latter abut along respective substantially annular contact surfaces 65, 66.

[0147] The first opening 47 includes a cylindrical hole having a diameter that is such as to house the first fixing element 42 with much reduced radial clearance.

[0148] When the first fixing element 42 abuts on the first coupling notch 62 and pushes the coupling element 60 against the rectilinear groove 49 along the second direction Y, the dosing unit 2 is locked in a firm and precise manner, prevented from moving in the first direction X, in the second direction Y and in a third direction Z that is orthogonal to the first direction X and to the second direction Y.

[0149] The second opening 48 includes, on the other hand, a through slot that is elongated in the first direction X to enable the second fixing element 43 to adapt to the position of the second coupling notch 63 and compensate for variations in distance between the latter and the first coupling notch 62 along the first direction X.

[0150] When the second fixing element 43 abuts on the second coupling notch 63 and pushes the coupling element 60 against the rectilinear groove 49, the dosing unit 2 is also locked rotationally around an axis that is parallel to the direction Y and passes through at the first fixing element 42.

[0151] The first coupling notch 62 and the second coupling notch 63 are made in corresponding inserts 67, 68 made of metal incorporated in the coupling element 60 to ensure greater stiffness and non-deformation of the aforesaid coupling notches 62, 63 and greater precision and resistance in the abutment on the fixing elements 42, 43.

[0152] The dosing unit 2 also includes a stop arranged to prevent or enable the piston 3 to extend inside the cavity 4 of the casing 5 along the first axis W1. In particular, the stop locks the piston 3 in relation to the casing 5 in a preset linear and angular position, in such a manner as to maintain the dosing unit 2 in an assembled condition R that is necessary for conveying and mounting/dismantling from the joint 10.

[0153] The stop includes, in particular, a stop pin 70 that is slidably assembled in a first housing 71, made on a side wall of the lower cylindrical portion 52c of the covering element 52, and arranged for engaging a second housing 73, obtained on an external wall 6a of the first end portion 6, at the opening of the seat 16.

[0154] The second housing 73 includes a hole having dimensions that are substantially equivalent to those of the stop pin 70.

[0155] The stop pin 70 is movable parallel to the second direction Y, i.e. perpendicularly to the first longitudinal axis W1 and is moved by a driving device of the supporting device 40 between a retracted position and an extended position. In the retracted position the stop pin 70 is completely contained in the first housing 71 in such a manner as not to interact with the first end portion 6 and enable the piston 3 to move. In the extended position the stop pin 70 is inserted into the second housing 73 and prevents the piston 3 from moving along and rotating around the first longitudinal axis W1 determining the assembled condition R of the dosing unit 2.

[0156] A drive pin 75, fixed transversely to the stop pin 70, is engaged by a drive stem 74 of the driving device. The drive stem 74 is parallel to the stop pin 70 and is driven by a linear actuating device 76, including for example a pneumatic cylinder, of the driving device. The drive stem 74 has a radial groove that is suitable for receiving the drive pin 75.

[0157] In a mounting step of mounting the dosing unit 2 on the supporting device 40, the operator supports the dosing unit 2, arranged in the assembled condition R, by means of the gripping portion 52a and inserts the coupling element 60 inside the guide 41 along the first direction X. The clearance between the coupling element 60 and the rectilinear groove 49 of the guide 41 permits easy and rapid insertion.

[0158] With the fixing elements 42, 43 maintained in the retracted position by the respective actuators 44, 45 inside the respective openings 47, 48, the coupling element 60 slides inside the guide 41 until it reaches a final position in which the aforementioned fixing elements 42, 43, pushed by the respective actuators 44, 45 to a protruding position abut on the respective coupling notches 62, 63, locking the dosing unit 2 in the mounting configuration A.

[0159] In this configuration, the drive pin 75 of the stop pin 70 is housed in the radial groove of the drive stem 74.

[0160] By performing the operation in reverse order, i.e. by removing the coupling element 60 from the guide 41, with the fixing elements 42, 43 maintained in the retracted position by the respective actuators 44, 45, it is possible to dismantle the dosing unit 2 from the supporting device 40.

[0161] Once the dosing unit 2 is inserted in the supporting device 40, the stop pin 70 still maintains the piston 3 fixed to the casing 5, locked in the assembled condition R in a set linear and angular position to enable the movement mechanism 101 to move the joint 10 along the second longitudinal axis W2 until the clutch portion 11 is inserted inside the seat 16 of the first end portion 6. Once the locking device 12 has been driven to mutually fix the clutch portion 11 to the seat 16, the stop pin 70 is disengaged from the piston 3. In particular, the linear actuating device 76 is activated in such a manner as to move the stop pin 70 in the retracted position so as to enable the piston 3 to move freely.

[0162] In one version of the apparatus not illustrated in the figures, the stop pin 70 engages a third housing made in the guide 41, to prevent the coupling element 60 from sliding, i.e. to prevent the dosing unit 2 from being extracted from the supporting device 40.

[0163] Owing to the dosing apparatus 1 of the invention it is thus possible to connect and lock the dosing unit to the respective supporting device 40 in a quick, easy and simultaneously precise and firm manner.

[0164] It is important to note that the mounting procedure can be performed by only one operator and is made particularly easy by the shape and the dimensions of the guide 41 and the clearance of the coupling device 60. The fixing elements driven by the respective actuators 44, 45 further enable the dosing unit 2 to be locked automatically when the latter has reached the desired position.

[0165] The entire mounting operation is made even easier by the stop, and in particular by the stop pin 70 that in the assembled condition R, fixes the piston 3 to the casing 5. In this manner, the operator can support the dosing unit 2 by the gripping portion 52a and insert the coupling element 60 inside the guide 41 along the first direction X without worrying about also supporting the piston 3, as usually occurs in known dosing syringes.

[0166] It should also be noted that the disengagement of the stop 70 from the piston 3 to enable movement in the cavity 4 occurs automatically by means of the driving device, in particular the drive stem 74 and the linear actuating device 76.

[0167] The procedure for dismantling the dosing unit 2 from the supporting device 40 is also easy and quick and occurs by manually removing the coupling device 60 from the guide 41 along the first direction X.