Abstract:
A dispensing cartridge, particularly for dental impression materials, comprises a locking member for locking a tip to the dispensing cartridge and/or to a container accommodated in the dispensing cartridge. The locking member has a first end and a second end, and is pivotally connectable with the dispensing cartridge at the first end. The second end of the locking member is adapted for releasable locking engagement with the tip. Furthermore, the locking member comprises a first portion that provides a grasping feature for the user for manipulating the dispensing cartridge at the locking member.

Description:
[0001]     This application claims priority from European Application No. 05026606.3, filed Dec. 6, 2005.  
       FIELD OF THE INVENTION  
       [0002]     The present invention relates to a dispensing cartridge, particularly for dental impression materials, of the type adapted to be releaseably received in an applicator unit having a moveable plunger.  
       BACKGROUND OF THE INVENTION  
       [0003]     A number of dispensing devices are available for dispensing various types of materials. In many instances, the dispensing device is an assembly that includes a reusable dispenser or applicator and a disposable cartridge. The cartridge typically comprises one or more compartments. Container, such as foil bags, containing the material to be dispensed are accommodated in the compartments of the cartridge. The cartridge contains a quantity of a material to be dispensed and is releaseably received in a receptacle or chamber of the applicator.  
         [0004]     In one type of dispensing devices, that include an applicator and a cartridge, the applicator has a plunger that is advanced by the user during a dispensing operation. Often, the plunger is positioned at an open end of the cartridge and bears against a piston within the cartridge. As the plunger is advanced to move the piston, the piston expels a quantity of material through a front outlet opening of the cartridge, where it may be mixed with material expelled from another cartridge, or used by itself. Dispensing devices with cartridges are often used in the field of dentistry for mixing and dispensing dental compositions of two components, such as impression materials, restoratives, adhesives, cements, etching gels, sealants and the like. The dispensing cartridge of such devices is made from a plastic material and comprises two compartments formed by two cylindrical bodies arranged in parallel to each other. Each compartment contains a specific component, usually a base paste or a catalyst paste, each contained within its own container, such as a foil or plastic bag. These two components are pressed from their respective foil bags out into a mixing tip where the required dental material is prepared. The pressure further urges the mixture out of the mixing tip so that the dental professional can use it as desired.  
         [0005]     One type of such dispensing devices is an assembly (e.g., the Garant™ dispenser available from 3M ESPE AG) that includes a reusable, hand-operated applicator and a disposable cartridge (e.g., the cartridge for the polyether impression material Permadyne™ Garant™ available from 3M ESPE AG). The two compartments are of the same cylindrical shape and size and are pre-filled with the two components to be mixed and dispensed.  
         [0006]     Another type of such dispensing devices is an automatic dispensing system (e.g., Pentamix™ available from 3M ESPE AG) that includes a motor-driven mixing or applicator unit and reusable and interchangeable cartridges (e.g., the cartridge for the polyether impression material Impregum™ Penta™ H DuoSoft, or the cartridge for the polyether impression material Permadyne™ Penta™, or the cartridge for the vinyl polysiloxane impression material Express™ Penta™ H, all available from 3M ESPE AG). The applicator unit comprises a space that receives the cartridge, and a cover that closes the space once the cartridge is placed in the dispensing device. The two cylindrical compartments of the cartridge have different diameters, and, in use, each accommodates a disposable foil bag pre-filled with the respective component. The larger compartment accommodates the foil bag with the base paste. The smaller compartment accommodates the foil bag with the catalyst paste. The mixing or applicator unit comprises a chamber for holding the cartridge and two parallel motor-driven plungers designed to plunge into the respective compartments and to exert pressure on the components contained in the foil bags. Both foil bags comprise a respective cap that fits onto the rim of the respective cylindrical body of the dispensing cartridge. A pivotable lever is used for locking the mixing tip so that it does not fall off of the caps of the foil bags when pressure is applied by the plungers.  
         [0007]      FIG. 1  shows such a conventional cartridge  1  having two parallel cylindrical compartments  2 ,  3  with different diameters. In  FIG. 1 , each compartment already accommodates a foil bag comprising respective caps  4 ,  5 . Each cap comprises an outlet tube (in  FIG. 1 , only the outlet tube  6  of cap  4  is shown), and adjacent to these outlet tubes is a mixing tip  7 . A lever  8  that extends along the longitudinal axis of the cartridge is pivotally hinged to the cartridge at its rear end. At the front end of the lever  8 , the lever comprises an essentially U-shaped locking member  9 , comprising two locking arms that engage corresponding locking surfaces or flanges of the mixing tip  7 . This positions the mixing tip properly relative to the outlet tubes  6  of the caps.  
         [0008]      FIG. 2  shows the cartridge  1  with the lever  8  in its fully engaged position. Due to the two locking arms engaging a circumferential flange at the rear end of the mixing tip  7 , the mixing tip  7  is held tight against the outlet tubes  6  of the foil bag caps  4 ,  5 . In order to hold the lever  8  in its engaged state, an engagement mechanism  10  is provided which engages a corresponding surface at the underside of the lever  8 . This engagement mechanism  10  can be released by means of a release slide  11 . In order to facilitate a quick release of the lever  8  from mixing tip  7 , a leaf spring  12  is provided adjacent to the lever hinge  13 . Once the engagement mechanism  10  is released with the release slide  11 , lever  8  springs upwards and away from the mixing tip  7  due to the bias force of the leaf spring  12 .  
         [0009]      FIGS. 1 and 2  also show a handle  14  that is provided at one side of the cartridge, specifically on the side of the larger diameter compartment  3 . With this handle  14 , the cartridge  1  can be picked up and removed from the applicator unit, for example, so that the foil bags can easily be changed. However, since the handle  14  is provided at a side of the cartridge  1  like a wing, removal of the entire cartridge  1  from the mixing unit might be inconvenient to the user.  
         [0010]     EP 1 044 727 A2 relates to a device for mixing and dispensing of a viscous liquid consisting of at least two components via two pistons. The liquid components are held in containers that are part of an insert and connected to a mixer. The pistons are arranged in a housing of the device and act upon such containers. The insert is accommodated in a cartridge that is part of a housing attachment. The cartridge is rotatably connected with the housing attachment so that it is rotatable between an operating position and an open position, wherein the insert can be removed from or inserted into the cartridge in the open position, and the insert can be secured in the cartridge in the operating position.  
         [0011]     U.S. Pat. No. 5,184,757 generally relates to gun-type dispensers for discharging a viscous fluid or paste, such as a sealing or bonding agent, from a container storing this agent. The gun includes a pair of cylindrical barrels for accommodating sealed foil packs having stored therein two components to be extruded and intermixed. Fitting into the leading ends of barrels and are end caps and of a mixing manifold. The manifold, which is removable from the barrel, is locked in place by a swing gate having a pair of parallel arms whose rear ends are pivotally connected to opposite sides of a stock piece. Secured to the front ends of these arms is a gate which when the gate is lowered engages the exposed faces of caps. When the swing gate is thereafter raised, one may then withdraw the manifold from the barrels.  
         [0012]     U.S. Pat. No. 2,634,888 relates to a dispensing gun with means for inserting removable containers. The apparatus described in U.S. Pat. No. 2,634,888 comprises essentially a handle carrying a manual mechanism for expelling the contents the cartridge and having means for positioning the rear end of the cartridge; a cup-like member to engage the front end of the cartridge and an extensible connecting device between said front engager and the handle whereby the cartridge may be effectively clamped in the apparatus to constitute the barrel of the gun or be released therefrom when empty. The clamping mechanism comprises a pair of frame bars extending parallel with each other on opposite sides of the cartridge, and have sliding or telescoping engagement with a pair of side bars which are secured to the front abutment. An operating lever is pivotably linked to the frame bars, and the operating lever and suitable linkage connects with the bars in a manner to spread them or contract them. With such arrangement, which is shown in FIG. 2 of U.S. Pat. No. 2,634,888 for example, a pivotal or rotational movement of the operating lever is translated into a translational movement of the frame bars and side bars relative to each other in order to clamp the cartridge in the apparatus.  
         [0013]     EP-A-1 602 342 (document under Art. 54(3) EPC) relates to a dispensing cartridge having a locking assembly for locking a tip in position relative to at least one compartment. The locking assembly comprises a first movable member comprising a first end and a second movable member comprising a first end and a second end. The second end of the second movable member is adapted for releasable locking engagement with the tip. The first movable member is operationally connected to the second movable member such that a movement of the first end of the first movable member is transmitted to the first end of the second movable member causing the second movable member to also move. Movement of the first end of the first movable member in a first direction causes the second end of the second movable member to release the tip, and movement of the first end of the first movable member in a second direction causes the second end of the second movable member to engage the tip. The first movable member may form part of a handle.  
         [0014]     Further reference is made to EP-A-0 291 753, EP-A-0 910 995, WO 97/18145, DE-A-100 38 882, and DE-A-34 18 052.  
       SUMMARY OF THE INVENTION  
       [0015]     According to a first aspect, the invention provides a dispensing cartridge, particularly for dental impression materials, comprising a locking member for locking, for example a tip to the dispensing cartridge and/or to a container accommodated in the dispensing cartridge. The locking member has a first end and a second end, and is pivotally connectable with the dispensing cartridge at the first end. The second end of the locking member is adapted for releasable locking engagement, for example with the tip. Furthermore, the locking member comprises a first portion that provides a grip for the user to manipulate the dispensing cartridge. Preferably, the grip of the locking member allows grasping of the dispensing cartridge and insertion into or removal from an applicator unit while the locking member is in locking engagement with the tip.  
         [0016]     In the context of the present invention, the term “locking” means that slight movement is permitted so long as it does not interfere with the function of the dispensing cartridge.  
         [0017]     It is preferred that the dispensing cartridge of the invention comprises a one-piece locking member.  
         [0018]     The locking member is preferably elongated, and, for example, forms a lever arm. In the locking position of the locking member, the locking member preferably extends along the longitudinal axis of the dispensing cartridge.  
         [0019]     The first portion of the locking member providing a grip is preferably is located in the area of the first end of the locking member.  
         [0020]     According to a first preferred embodiment of the dispensing cartridge of the invention, the first portion of the locking member is raised relative to the dispensing cartridge to provide a handle for the user. The raised first portion preferably has a first section and a second section extending upwards from the locking member surface. The first section and the second section are preferably spaced from each other and connected by a third section. More preferably, the first, second, and third sections form an inverse U. Alternatively, the first, second, and third sections form a convex-shaped raised portion. In this embodiment, the first section is preferably adjacent to the first end of the locking member, whereas the second section is spaced from the first section in longitudinal direction of the locking member. As an option, the raised portion extends along substantially the whole length of the locking member.  
         [0021]     According to a second preferred embodiment of the dispensing cartridge of the invention, the grip consists of a rib extending from the surface of the locking member. According to the present invention, the term “rib” means an essentially closed surface that can be grasped by applying pressure from both sides. The rib preferably extends upwards from the surface of locking member, where the term “upwards” is relative to a state in which the locking member engages the tip and is substantially horizontally oriented. Preferably, the rib extends along the longitudinal axis of the locking member. Alternatively, the rib extends across the longitudinal axis of the locking member. In this case, the rib preferably is in the form of an inverse U thus providing a through hole between the surface of the locking member and the U.  
         [0022]     In a dispensing cartridge according to a third embodiment of the invention, the grip consists of at least one through hole through the first portion of the locking member. The at least one through hole is preferably sized such that a user&#39;s finger is insertable through the hole.  
         [0023]     It is preferred according to all embodiments of the invention that the locking member is removably connectable to the dispensing cartridge.  
         [0024]     The dispensing cartridge of the invention is used with dispensing devices such as the above-described Pentamix™ automatic dispensing system. In this case, the cover of the dispensing device may eventually comprise a recess to accommodate the handle of the locking member of the invention.  
         [0025]     In the present dispensing cartridge, the at least one compartment comprises a body having an open end for receiving a plunger of an applicator, and having an outlet opening. The at least one compartment extends between the open end and outlet opening.  
         [0026]     The dispensing cartridge of the present inventions preferably contains a first compartment (preferably adapted for receiving a first container) comprising a base material and a second compartment (preferably adapted for receiving a second container) comprising a catalyst material that together form a dental impression material after having been mixed. Preferably, the dental impression material is a polyether impression material or polysiloxane impression material. The containers are preferably foil bags each closed by a cap, each of which comprises an outlet tube. The locking member preferably comprises at least one engagement element for engaging such cap(s) of the container.  
         [0027]     The locking member is preferably adapted for locking the tip to the at least one container. For example, the second end of the locking member comprises engagement surfaces that are engageable with a complementary engagement surface at the tip. In more detail, the second end of the locking member is preferably substantially U-shaped, and the two legs of the U are engageable with a corresponding flange at the rear end of the tip.  
         [0028]     It is also preferred that the dispensing cartridge comprises a release mechanism for releasing the locking engagement of the locking member with the tip. In the preferred embodiment of a one-piece locking member, the term “one-piece” does not encompass the release mechanism.  
         [0029]     The tip usable with a dispensing cartridge according to the invention is preferably a dispensing tip or a mixing tip.  
         [0030]     According to a second aspect, the present invention provides a kit comprising an applicator unit comprising at least one plunger and at least one dispensing cartridge according to the invention. The invention also provides a kit comprising a dispensing cartridge according to the invention comprising a paste, and a tip.  
         [0031]     According to a further aspect of the invention, the grip for the user is extended from, and retractable into, the locking member. Thus, the grip is retractable into the cartridge assembly when not in use, but can be pulled upward when needed to function as a handle. This arrangement is advantageous because it saves space in the closed applicator unit. As an example, the retractable handle is spring-loaded so that when the top of the applicator unit is opened, the handle springs upward, but when the top is closed the handle is pressed downward, again saving space. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0032]     Preferred embodiments of the invention are described in more detail below with reference to the attached drawings, which are by way of example only.  
         [0033]      FIG. 1  is a front perspective view of a conventional dispensing cartridge;  
         [0034]      FIG. 2  is a front perspective view of the conventional dispensing cartridge of  FIG. 1  with the locking lever in its engaged position;  
         [0035]      FIG. 3  is a front perspective view of the dispensing cartridge according to one embodiment of the invention with the locking member in its open position;  
         [0036]      FIG. 4  is a front perspective view of dispensing cartridge of  FIG. 3  with the locking member in its engaged position;  
         [0037]      FIG. 5  is a front perspective view of the locking member of the dispensing cartridge of  FIGS. 3 and 4 ;  
         [0038]      FIG. 6  is a front perspective view of an alternative locking member shown in  FIG. 6 ;  
         [0039]      FIG. 7  is a front perspective view of an alternative locking member according to a further embodiment of the invention;  
         [0040]      FIG. 8  is a front perspective view of a dispensing cartridge according to a further embodiment of the invention with the locking member in its engaged position;  
         [0041]      FIG. 9  is a front perspective view of a dispensing cartridge according to a further embodiment of the invention with the locking member in its engaged position;  
         [0042]      FIG. 10  is a front perspective view of a dispensing cartridge according to a further embodiment of the invention with the locking member in its engaged position; and  
         [0043]      FIG. 11  is a perspective view of the dispensing device with the cartridge of one embodiment the invention placed in the respective accommodating space. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0044]     An example of a dispensing cartridge of a first embodiment of the invention is illustrated in  FIGS. 3 and 4 , and is designated by reference numeral  100 . The cartridge  100  according to this embodiment comprises a first compartment with a body  112 . Specifically, the body  112  includes a rear open end  114  and a front outlet opening  116  that is spaced from the open end  114 . The compartment is elongated and extends from the rear open end  114  to the outlet opening  116 .  
         [0045]     The dispensing cartridge as shown in the Figures comprises a second compartment having a body  122 . The body  122  includes a rear open end  124  and a front outlet opening  126  that is remote from the open end  124 . The second compartment is elongated and extends from the open end  124  to the outlet opening  126 .  
         [0046]     In the illustrated embodiment, the dispensing cartridge  100  comprises a locking member  200  in the form of a pivotable lever arm that is connected at its rear end to the dispensing cartridge  100 . Locking member  200  is connected at its first end  212  to the remainder of the dispensing cartridge by a hinge  213 . Due to this connection, locking member  200  is rotatable about hinge  213  and can be angularly displaced as shown, e.g., in  FIG. 4 . In particular, locking member  200  is shown in  FIG. 4  in its non-engaged position, and is rotatable downwards, towards the two compartments of the dispensing cartridge  100 . In order to allow a defined non-engaged position of locking member  200  as shown in  FIG. 4 , a bias function, provided by for example a bias member like a coil spring, may be provided.  
         [0047]     The locking member  200  further comprises at its second end  214  a second portion that is substantially L-shaped. The second portion  230  comprises engagement surfaces for releasable engagement with corresponding engagement surfaces  132 , for example, an annular flange, of the mixing tip  130 . The second portion  230  is preferably U-shaped, as is best seen in  FIG. 4 . The two legs  233  and  234  of the U are formed such that they correspond to the annular engagement flange  132  of the mixing tip  130 . In the engaged position of the locking member  200 , i.e. in the locking position of the second portion  230  as shown in  FIG. 3 , the legs  233 ,  234  engage the engagement flange  132  of mixing tip  130  which prevents the mixing tip from being removed from the dispensing cartridge or from being pressed off of the dispensing cartridge due to the pressure applied by the pistons to the containers by the applicator unit. As shown in  FIG. 4 , the mixing tip  130  is connected to outlet tubes  119  of the caps  118 ,  128  of the containers, which are, for example, foil bags containing the material to be dispensed.  
         [0048]     In the preferred embodiment shown in FIGS.  3  to  5 , the grasping feature that enables the user to grasp the dispensing cartridge at the locking member is provided in the form of a portion of the locking member that is raised relative to the dispensing cartridge. The raised portion  220  of the locking member  200 , in the example shown in FIGS.  3  to  5 , comprises a first extending section  221  at the rear or first end of the locking member  200 , and a second extending section  222  closer to the second end  214  of the locking member  200 . These two sections  221  and  222  are connected by a third section  223 . Third section  223  extends substantially parallel to the remainder of the locking member  200  so that the two sections  221 ,  222 , and the third section  223  provide a structure in the form of an inverse U.  
         [0049]     As shown in  FIGS. 4 and 5 , the first upstanding section  221  terminates in third section  223 , which, in turn, terminates in second extending section  222 . Second extending section  222  then terminates into second portion  230  of the locking member  200 . An alternative to this design is shown in  FIG. 6 . Here, locking member  200   a  is formed like the locking member  200  shown in  FIG. 5 , but additionally comprises a fourth section  224  extending between the lower ends of the two extending sections  221 ,  222 . This section could add structural strength and stability to the locking member.  
         [0050]      FIG. 7  shows an alternative embodiment of the invention. Locking member  300  shown in  FIG. 7  comprises a rib  330  that extends from first portion  320 . In the embodiment shown in  FIG. 7 , the rib extends along the longitudinal axis of the locking member  300 , and provides another manner for a user to grasp the cartridge.  
         [0051]     According to the embodiment shown in  FIG. 8 , rib  430  extending from the first portion  420  of locking member  410  extends perpendicular to the longitudinal axis of the locking member.  
         [0052]     An alternative of the embodiment of  FIG. 8  is shown in  FIG. 9 . Here, the upstanding rib is provided in the form of an inverse U so that a channel or through hole is formed between the surface of the locking member  510  and the U formed by the rib  530 . This permits a user to insert a finger or tool into the through-hole to assist in removing the cartridge.  
         [0053]      FIG. 10  shows a further embodiment of the invention. According to this embodiment, locking member  610  comprises a first portion  620  with one or more through holes  630 . In  FIG. 10 , two through holes  630  are shown that are arranged along the longitudinal axis of the locking member  610 . The through holes are sized such that a user can insert his/her fingers through the hole to grasp the dispensing cartridge via the locking member  610 .  
         [0054]      FIG. 11  shows a dispensing device  700 . The dispensing cartridge of the embodiment shown in  FIGS. 3 and 4  is accommodated in the dispensing device. The locking member is open so that the mixing tip is not yet locked onto the cartridge.  
         [0055]     The present invention has now been described with reference to several embodiments thereof. It will be apparent to those skilled in the art that many changes can be made in the embodiments described without departing from the scope of the present invention. Thus the scope of the present invention should not be limited to the structures described in this application, but only by structures described by the language of the claims and the equivalents of those structures.