Abstract:
A nozzle for dispensing a viscous material from a source of the viscous material. The nozzle includes a dispensing orifice, a nozzle throat in flow communication with that orifice; and a transition in flow communication with the nozzle throat and the source of viscous material. These portions of the nozzle have a specific size relationship.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    The present application is a continuation-in-part of U.S. patent application Ser. No. 29/160,525, filed May 13, 2002, entitled A NOZZLE FOR DISPENSING VISCOUS MATERIAL, and U.S. patent application Ser. No. 29/160,530, also filed May 13, 2002, entitled A NOZZLE FOR DISPENSING VISCOUS MATERIAL. The entire content of these applications is specifically incorporated by reference herein. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to nozzles for dispensing viscous material from pliable containers.  
         BACKGROUND OF THE INVENTION  
         [0003]    A number of viscous materials are dispensed from collapsible containers where the pressure for dispensing the viscous material is generated by applying pressure to a pliable container. The shape of the material issuing from the container is determined by the cross-sectional shape of the nozzle forming the open end of such containers. The viscous material within the container flows under the influence of the pressure generated by collapsing the container toward the nozzle, and is extruded therefrom through the nozzle and its dispensing orifice. The cross-sectional shape of the extruded viscous material is determined by a cross-sectional shape of the dispensing orifice.  
           [0004]    The prior art shows a number of nozzle orifice configurations and while most of the prior art orifices are circular, forming a cylindrical extrudate of the viscous material being dispensed, a great many different shapes have been used for nozzle orifices. See for example the interior nozzle orifices of FIGS. 4 through 7 of U.S. Pat. No. 5,823,387 to Manadanas, et al. Elongated dispensing orifices are disclosed in a number of references, including European Patent Application 01 78 377 A2.  
           [0005]    Aside from the configuration of the dispensing orifice in a nozzle structure for dispensing a viscous material, the nozzle structure must be such that the pressure generated from collapsing the container, usually hand pressure, is sufficient to extrude an adequate amount of viscous material from the dispensing nozzle, with a shape and at a rate that is suitable for the particular application.  
           [0006]    In addition, the nozzle structure should be capable of being formed in conventional molding apparatus with tooling that is not inordinately expensive to manufacture.  
         SUMMARY OF THE INVENTION  
         [0007]    To solve these and other problems in the prior art, there is provided a nozzle for dispensing a viscous material from a source of the viscous material. The nozzle includes a dispensing orifice, a nozzle throat in flow communication with that orifice, and a transition in flow communication with the nozzle throat and the source of viscous material. The source of the viscous material is a container having an interior cross-sectional area, at the interface of the source and transition, of a value A. The transition has a cross-sectional area, at the interface with the nozzle throat, of a value B. The dispensing orifice has a cross-sectional area, in a plane perpendicular to flow through the orifice of a value C. Where the nozzle includes a generally rectangular, “race track,” or elliptical dispensing orifice, A is in the range of from 2 to 3 of B and B is in the range of from 25 to 35 of C.  
           [0008]    Nozzles having such configurations are capable of dispensing viscous material in a desired shape, at acceptable rates, without excessive pressure being developed in the container. Moreover, such nozzles can be fabricated and attached to the containers in automated machinery that need not include complex tooling.  
           [0009]    Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.  
           [0010]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.  
           [0011]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a left perspective view of one embodiment of the present invention having a generally rectangular nozzle orifice truncated at an angle to the general direction of flow from the nozzle;  
         [0013]    [0013]FIG. 2 is a side view of the embodiment of FIG. 1;  
         [0014]    [0014]FIG. 3 is an end view toward the rectangular nozzle orifice of the embodiment of FIG. 1;  
         [0015]    [0015]FIG. 4 is a view from inside the container toward the rectangular nozzle orifice of the embodiment of FIG. 1;  
         [0016]    [0016]FIG. 5 is an end view toward the nozzle orifice of another embodiment, where the nozzle orifice is elliptical;  
         [0017]    [0017]FIG. 6 is a view from inside a container toward the nozzle orifice the embodiment of FIG. 5;  
         [0018]    [0018]FIG. 7 is a side view of the embodiment of FIG. 5; and  
         [0019]    [0019]FIG. 8 is a cross-sectional view of the embodiment of FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]    Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are be used throughout the drawings to refer to the same or like parts.  
         [0021]    In accordance with the invention, there is a nozzle for dispensing viscous materials. Such materials may include adhesives, caulk, toothpaste, dental adhesive, food products, pigments, or the like. The purpose of the nozzle is to dispense the viscous material in a shape, and at such a rate, as to facilitate the efficient and effective delivery of the viscous material to a receiving surface. The source of such material is a container.  
         [0022]    As here embodied, and shown in FIG. 1, the container is a tube  10  having a closed end  12  opposite the nozzle  14 . The configuration of the container is not critical to the present invention. The container can be a cylindrical tube with a movable end that is advanced to create pressure on the viscous material in the container, a tube that is collapsible under the influence of external pressure, or any source of viscous material that can generate pressure to force the viscous material out of the container toward the nozzle.  
         [0023]    In accordance with the invention, there is included a nozzle that includes a dispensing orifice. As here embodied, and depicted in FIGS.  1 - 4  and  8 , there is a nozzle  14  having a nozzle orifice  16  that is generally rectangular with radiused corners  18 . The radius of curvature is not known to be critical, however, without radiused corners (i.e. sharp, square corners) the flow rate in such sharp corners is significantly lower that in the remainder of the nozzle orifice and viscous material can accumulate in such sharp corners. For that reason, it is preferred that the corners of a nozzle orifice that is generally rectangular have radiused corners, as is most clearly depicted in FIGS. 3 and 4. In some embodiments (not shown) the opposite short ends of the rectangular orifice have a radius equal to one-half of the dimension across the end, a so called “race track” shape.  
         [0024]    In embodiments where the extremity of the nozzle is truncated at an angle to the flow of viscous material passing through the orifice, the cross sectional area of the orifice is measured (for purposes of comparison with other cross sectional areas in the apparatus) in a direction perpendicular to the passage through the nozzle.  
         [0025]    In a preferred embodiment, the generally rectangular nozzle opening has a length to width ratio in the range of from 1.8 to 2.2. A most preferred embodiment has radiused corners, with a radius less than one half of the width of the orifice, and a length to width ratio of 1.96.  
         [0026]    Where the pressure in the viscous material is relatively low and the viscous material is not significantly compressible, the shape of the nozzle orifice determines the shape of the material being dispensed.  
         [0027]    As here embodied and depicted in FIGS. 5 and 6, the nozzle orifice  16  is elliptical in cross section. In a preferred embodiment, the elliptical nozzle opening has a minor axis (the smaller interior dimension  20 ) about 50% of the minor axis (the larger interior dimension  22 ) of the elliptical orifice.  
         [0028]    In accordance with the invention, the nozzle of the present invention includes a nozzle throat in flow communication with the nozzle orifice. As here embodied, and most clearly depicted in FIG. 8, the nozzle  14  includes a nozzle throat  24  in flow communication through channel  26  to the orifice  16 .  
         [0029]    In accordance with the invention, the nozzle includes a transition in flow communication with the nozzle throat and the source of viscous material. As here embodied and depicted in FIG. 8, the nozzle  14  includes the transition  28  that, at one extremity (the nozzle throat  24 ) interfaces with the channel  26 , and at the opposite extremity (nozzle entrance  30 ) it interfaces with the container  10 .  
         [0030]    In accordance with the invention, the dispensing nozzle orifice has a cross-sectional area (measured perpendicular to the flow of viscous material through the nozzle) of a value C. As here embodied, the nozzle orifice  16  has a cross-sectional area of C.  
         [0031]    In accordance with the invention, the transition has a cross-sectional area at the interface with said nozzle throat of B. As here embodied, and most clearly depicted in FIG. 8, the transition  28  is adjacent to nozzle throat  24 , and the nozzle throat  24  has a cross sectional area of B. The opposite extremity of the transition  28  interfaces with the container  10  at nozzle entrance  30 .  
         [0032]    In accordance with the invention, the source of viscous material comprises a container having an interior cross-sectional area at the interface of the source and the transition in the nozzle of A. As here embodied, and depicted in FIG. 8, the tube  10  has a nozzle entrance  30  having a cross-sectional area of A.  
         [0033]    In the embodiment where the dispensing orifice is generally rectangular, the value of A is in the range of from 2 to 3 of B, and the value of B is in the range of from 25 to 30 of C. In a preferred embodiment where the viscous material is either dental adhesive or toothpaste, it is preferred that A is about 3.4 in 2 , B is about 1.35 in 2 , and C is about 0.0254 in 2 .  
         [0034]    In a preferred embodiment the nozzle throat has a substantially constant cross-sectional area along the longitudinal axis of the nozzle. As here embodied, and shown in FIG. 8 the nozzle includes and interior nozzle throat  24  that extends along the longitudinal axis of the nozzle  14 . As here embodied the nozzle throat includes a step  32  that facilitates the manufacture of the tooling that forms the nozzle without interfering significantly with the flow of viscous material through the nozzle. As here embodied the interior surface of the nozzle includes a smooth channel  26  transitioning in a taper from the cylindrical nozzle throat  24  to the dispensing orifice  16 . The channel  26  need not be entirely tapered and in FIG. 8 the last portion of the channel  26  has generally parallel sides.  
         [0035]    As shown in FIG. 2, the dispensing orifice need not be perpendicular to the flow of viscous material through the nozzle. As here embodied, the dispensing orifice is at an angle of greater than ninety degrees to the direction of flow of the viscous material. This can also be the case where the nozzle orifice is circular or elliptical.  
         [0036]    As here embodied, the nozzle includes a substantially cylindrical exterior surface  34  between the transition  28  and the dispensing orifice  16 . That surface  34  includes a plurality of threads  36 . In this embodiment, the threads comprise three generally parallel threads  36 , each thread starting at a location around the circumference of the cylindrical exterior surface at angularly spaced starting points. It is preferred (and is shown in FIGS. 3 and 5) that the angularly spaced starting points are spaced 120 degrees around the circumference. It is further preferred that the plurality of threads have a pitch of 0.25 (4 threads per inch) and extend approximately 200 degrees around the circumference of the cylindrical exterior surface  34 .  
         [0037]    Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.