Abstract:
An applicator for extruding strings of cake icing or other flowable semi-solid material comprises a longitudinally slotted screw rotated in a fixed nut and thereby advanced longitudinally in a tube, and a rotating nozzle assembly having a partition extending into the slot or slots of the screw whereby the nozzle assembly rotates with the screw as the screw advances. Pistons formed at an end of the screw fit cylinders formed by the interior wall of the tube and the partition to eject icing through one or more nozzles of the rotating nozzle assembly.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention is an apparatus and method for extruding a semi-solid flowable material, having utility in the field of cake decoration, and potential uses in the production of other edible products as well as in the production of various decorative products. The term “semi-solid flowable material” as used herein refers to a material that is capable of being extruded through a nozzle upon the application of pressure at ambient temperature, but sustaining its shape when the applied force is limited to gravitational force. More particularly, the invention relates to the application of a semi-solid flowable material in such a way that the extruded product is twisted, and to variations in which two or more strings of extruded product are twisted about one another to form intertwined helical strands, which can be of different colors, or of different thicknesses, or both. 
       BACKGROUND OF THE INVENTION 
       [0002]    In cake decorating, after a uniform layer of icing is applied, the cake is often trimmed with strings of icing applied by means of an extruder. The extruder can be in the form of a flexible bag having an attached nozzle though which icing in the bag is forced by manual squeezing of the bag. Other common forms of extruders include an extruder comprising a cylindrical chamber, an outlet nozzle through which icing flows from the interior of the cylindrical chamber, and a plunger, movable axially in the chamber, for applying pressure to the icing and thereby extruding the icing through the nozzle. In some extruders, the plunger is operated manually. In others, the plunger is motor-driven. The nozzles can have apertures configured to produce strings of icing of various sizes and cross-sectional shapes. For example, the nozzle aperture can be designed to extrude a string of icing in the form of a flat ribbon, or one having a star-shaped cross-section. 
         [0003]    Extruders have also been designed with rotating nozzles for producing twisted strings of icing. For example United States Patent Publication 2008/0089967, published Apr. 17, 2008, describes a piping bag having a rotatable nozzle. Other extruders have been devised for dispensing icing through plural adjacent nozzles that can rotate about a central axis to produce a rope-like string of icing. Examples of such extruders are described in U.S. Pat. Nos. 7,713,585, granted May 21, 1929, 5,492,706, granted Feb. 20, 1996, and 5,603,965, granted Feb. 18, 1997. Despite the developments exemplified by the above-mentioned patents and patent publication, a need remains for a simple and easy-to-use extruder capable of delivering a twisted string of icing of uniform quality, consisting of a single strand delivered through a single nozzle, or plural strands delivered through two or more nozzles and twisted about one another. 
       SUMMARY OF THE INVENTION 
       [0004]    Briefly, the invention is an extrusion applicator in which semi-solid material is delivered through a rotating nozzle assembly by a pump. The nozzle assembly and pump are mechanically interconnected for simultaneous operation whereby, as a motive force is applied to the pump to operate the pump, the same motive force rotates the nozzle assembly. 
         [0005]    In an embodiment of the invention, a rotatable member is arranged to transmit operating power both to the nozzle assembly and to the pump. In a preferred embodiment, the pump includes a screw mechanism, and the nozzle assembly is coupled to the screw mechanism so that the nozzle assembly rotates upon operation of the screw mechanism. 
         [0006]    In the preferred embodiment, the nozzle assembly is mounted for rotation about a discharge axis, and has at least one discharge opening. Each discharge opening is oriented to discharge flowable material along the discharge axis. However, the discharge openings are not necessarily aligned with the discharge axis, and can be offset from, and directed obliquely toward, the discharge axis. Even in the case of a nozzle assembly having a single discharge opening, the opening can be offset from, and directed obliquely toward, the discharge axis. 
         [0007]    The pump comprises, for each discharge opening, at least one cylinder in communication with the discharge opening and a piston movable in the cylinder for exerting pressure on flowable material therein to cause the material to be discharged through the discharge opening. The term “cylinder” as used herein is not limited to a circular cylinder, and can be any straight tubular structure having a uniform transverse cross-section such that a piston having a conforming cross-sectional shape can slide therein while maintaining contact with, or closely spaced relationship with, the interior wall of the cylinder. 
         [0008]    The pump drive comprises a relatively rotatable screw and nut having mating threads. The screw extends along a screw axis, and the pump drive is connected to each piston for moving the piston in its cylinder in response to relative movement of the screw and nut along the screw axis. 
         [0009]    The rotatable member, which can be a shaft of a hand crank, the shaft of an electric motor, or any of various devices for transmitting torque, is mechanically connected both to the nozzle assembly and to the pump drive, and simultaneously imparts rotation to the nozzle assembly while imparting relative rotation to the screw and nut, so that the nozzle assembly rotates as the pump causes flowable material to be discharged through each discharge opening. Rotation of the nozzle assembly imparts a twist to the flowable material as it is discharged. 
         [0010]    In an embodiment of the applicator, it is the screw of the pump drive that is coupled to the nozzle assembly so that the screw rotates with the nozzle assembly. The screw axis can coincide with the discharge axis about which the nozzle assembly rotates. 
         [0011]    The screw axis of the applicator preferably coincides with the discharge axis and the screw extends axially within a rotatable housing having a cylindrical, inner wall coaxial with the screw. This cylindrical inner wall is preferably, although not necessarily, in the form of a circular cylinder. The nozzle assembly is also preferably located at one end of the housing and rotatable with the housing. A portion of the screw extending from a first end thereof is longitudinally divided into at least two parts, so that adjacent parts of the screw are separated by a space composed of at least one longitudinal slot. A partition extends along the direction of the discharge axis into the space between the parts of the piston, and has edges that meet the inner wall of the housing. Thus, the partition and the inner wall of the housing cooperate to form sector-shaped cylinders, each constituting a cylinder of the pump. Each piston is constituted by a divided part of the first end of the screw. The screw is rotatable by the rotatable member, and axially movable along the partition. The rotatable member imparts rotation to the nozzle assembly by rotating the partition, which can be fixed to the nozzle assembly. 
         [0012]    In an embodiment of the invention, the partition has a Y-shaped cross-section, and divides the interior of housing into three sector-shaped cylinders. In this embodiment the screw is divided longitudinally into three parts, one of the three parts extending into each of the three sector-shaped cylinders. 
         [0013]    In the preferred embodiments, a first of two opposite ends of the housing is located adjacent the discharge opening, the nozzle assembly is removably connected to the first end of the housing, preferably by cooperating threads formed on the first end of the housing and on the nozzle assembly. If the partition is fixed to the nozzle assembly, it can be removed with the nozzle assembly, facilitating cleaning of the cylinders. The removability of the partition with the nozzle assembly also makes it possible to replace the partition with one having another configuration, e.g., to replace a flat partition with a Y-shaped partition. The screw can also be replaced when the partition is replaced. 
         [0014]    Although a flat or Y-shaped partition, or one having another configuration, can be used with a nozzle assembly having a single discharge opening, it can also be used with a nozzle assembly having plural discharge openings. Where the nozzle assembly has at least two discharge openings, and a corresponding number of cylinders, each cylinder can be in communication with a different one of the discharge openings. 
         [0015]    In an embodiment of the applicator in which the nozzle assembly has at least two discharge openings, the discharge openings can be oriented for discharge of flowable material in oblique relation to the discharge axis. The openings can be oriented for discharge of flowable material toward the discharge axis, and can be formed in plural nozzles, each of which is angularly adjustable. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a longitudinal cross-sectional view of an applicator according to a first embodiment of the invention; 
           [0017]      FIG. 1A  is an enlarged auxiliary view showing details of an area outlined by a broken line in  FIG. 1 ; 
           [0018]      FIG. 2  is a cross-sectional view taken on plane  2 - 2  in  FIG. 1 ; 
           [0019]      FIG. 3  is a cross-sectional view taken on plane  3 - 3  in  FIG. 1 , showing the drive mechanism for rotating the two-part screw of the first embodiment; 
           [0020]      FIG. 4  is a longitudinal cross-sectional view of an applicator according to a second embodiment of the invention; 
           [0021]      FIG. 5  is a perspective view showing the nozzle fitting, a Y-shaped partition, and plunger of an applicator in accordance with a third embodiment; 
           [0022]      FIG. 6  is a cross-sectional view taken on plane  6 - 6  in  FIG. 6 ; 
           [0023]      FIG. 7  is a cross-sectional view, corresponding to  FIG. 3 , but showing the drive mechanism for rotating the three-part screw of  FIG. 5 ; and 
           [0024]      FIG. 8  is a perspective view showing the applicator of the third embodiment in use. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    As shown in  FIG. 1 , a first embodiment of the invention is an applicator  10  comprising a drive unit  12 , a pump section  14 , and a nozzle assembly  16 . The drive unit includes a hollow casing  18  having a handle. Inside the handle, a reversible motor  20  is arranged to rotate a rotating member  22  through a speed-reducing gear train  24 . Member  22  (also shown in  FIG. 3 ) is in the form of a large diameter gear, having teeth  26  in mesh with the teeth of a pinion  28  of the gear train. 
         [0026]    The motor  20  is powered by an external, low voltage, power supply  30  through momentary switches  32  and  34 , which are alternatively closed by operation of a rocker  36  on the handle. Pressing lower surface  38  on the rocker causes the shaft of the motor to rotate in one direction, and pressing upper surface  40  on the rocker causes the shaft to rotate in the opposite direction. The direction of rotation of rotatable member  22  can therefore be reversed. 
         [0027]    An elongated screw  42  extends though an opening in the center of rotating member  22 . Its threads  44  mesh with threads  46  of a nut  48  formed in an opening of the drive unit  12 . As the screw rotates, it therefore moves axially in one direction or the other depending on its direction of rotation. 
         [0028]    The rotating member  22  is formed with an annular flange  50 , which extends radially outward, fitting into an annular slot  52  formed in the drive unit  12 , as shown in  FIG. 1A . The annular drive unit  12  is composed of an upper part  54  and a lower part  56  which are flanged and held together by fasteners  58  as shown in  FIG. 3 . The flange  50  of rotating member  22  can be inserted into the slot while the upper and lower parts are separate from each other. Although not shown in  FIG. 1 , in a modified version of the applicator, the drive unit can be constructed so that the part of the drive unit in which the nut is formed is unitary, the rotating member is retained by opposed semi-circular flanges formed on separate elements each secured to the unitary part of the drive unit, and housed in an enclosure which is also attached to the unitary part of the drive unit. 
         [0029]    As shown in  FIG. 3 , the central opening  60  in rotating member  22  has two opposed protrusions  62  and  64 , extending radially inward toward the center of the rotating member. The screw  42  has an elongated slot  67 , extending from a front end  68  to a location  71  near the rear end  72  of the screw. The slot  67  extends diametrically across the screw, and receives both of the two opposed protrusions  62  and  64 , so that the screw rotates with rotating member  22 . Thus, as the motor  20  drives the rotating member  22  through the speed reducing gear train  24 , the screw rotates in nut  48 , and moves forward or rearward, depending on its direction of rotation. 
         [0030]    The pump section  14  comprises a cylindrical sleeve  67  secured at one end to a ring-shaped fitting  69 , having a threaded protrusion removably threaded into the casing of the drive unit. Another ring-shaped fitting  70  is secured at the opposite end of the sleeve  66 . These fittings  69  and  70  cooperate with rings  72  and  74  on a hollow tube  76 , and with balls  78 , forming a bearing in which the tube  74  can rotate. The bearing ensures that the tube  76  rotates on an axis that is in fixed relationship to the casing of the drive unit, and is capable of sustaining thrust imparted to the tube by the pressure exerted by the screw on flowable material inside the tube. 
         [0031]    The nozzle assembly  16  is removably secured by threads to an end of tube  76  that projects from sleeve  66 , and includes a base  80  that is threaded to the end of the tube, and a nozzle  82  removably connected to the nozzle base  80 . The nozzle can be any one of a variety of conventional icing nozzles of the kind used with icing bags or other icing applicators. 
         [0032]    A partition  84 , in the form of a flat strip, is fixed to the removable nozzle base  80  and extends axially into the tube  76  to a location adjacent the nut  48 . The partition  84  extends diametrically across the interior of the tube as shown in  FIG. 2 , either contacting the inner wall of the tube, or coming into such close proximity to the inner wall of the tube as to impede passage of semi-solid flowable material from one side of the partition to the other. A spacing of 1 or 2 mm at the long edges of the partition will generally impede flow of most semi-solid flowable materials sufficiently. Furthermore, because the pressures in the flowable materials on both sides of the partition will usually be approximately equal, the equality of pressure will also impede flow of material from one side of the partition to the other. 
         [0033]    The partition extends into the slot  67  of the screw  42  as shown in  FIGS. 1 and 2 , and preferably has a thickness only slightly less than the width of the slot. Because the partition fits into the slot in the screw, rotation of the screw will impart torque to the nozzle assembly, causing the nozzle assembly  16  and the tube  76  to rotate along with the screw. Any clearance between the partition and the walls of the slot in the screw should be small to prevent excessive flow of flowable semi-solid material into the slot. 
         [0034]    The direction of the threads  86  by which the nozzle base is secured to the tube  74  should be such that the connection between the nozzle base and the tube becomes tighter as the tube rotates in a direction that causes the end  68  of the screw to move toward the nozzle assembly. As an alternative to threads, in order to avoid overtightening, or loosening of the nozzle assembly during twisting, a bayonet-type, twist and lock, connection, or any of various other connection means, can be utilized to connect the nozzle base to tube  74 . 
         [0035]    The end  68  of the screw is formed on a split circular enlargement composed of parts  88  and  90 , each integral with one of the two parts of the screw. The two parts of the enlargement serve as pistons, and the enlargement has a diameter such that it is in sliding contact with, or in close proximity to, the inner wall of the tube  76 . Any gap between the inner wall of the tube and the periphery of a piston should be small to avoid flow of material past the piston and into the space surrounding the screw. Generally, the size of the gap should be less than approximately 1 mm. 
         [0036]    The applicator of  FIGS. 1-3  can be operated in the following manner. First, if the pistons are not already withdrawn to a location near the proximal end of tube  76 , the motor  20  is operated by depression of the upper surface  40  of the rocker  36  to cause the screw to rotate in a direction such that it moves rearward, that is, toward the right in  FIG. 1 . The pump section  14  is rotated to remove it from the drive unit  12 . The interior of tube  76  of the pump section can then be filled with icing or other semi-solid flowable material, by the use of a suitable device such as a conventional plunger-type applicator. The cylindrical spaces on both sides of the partition  84  can be filled with icings having different colors or other different properties. Alternatively, both cylindrical spaces can be filled with the same icing composition. 
         [0037]    After having been charged with icing, the pump section is reattached to the drive unit, and the applicator can then be operated by depression of surface  38  of the rocker switch. As the motor operates, the screw  42  simultaneously rotates and moves forward in tube  76 , forcing icing out through the opening of nozzle  82 . Because the nozzle base  80  is fixed to the partition, and the partition extends into slot  67  of the screw, the nozzle and the tube  76  to which the nozzle and nozzle base are attached, rotate with the screw. Consequently, the icing extruded through the nozzle twists as it is ejected, forming a twisted string. If the icings on opposite sides of the partition are of different colors, a string of icing composed of two intertwined helices of different colors is produced. In general the two different icings will only partially merge in the space within the nozzle  82  and the nozzle base  80 , and consequently the twisted, two-color, string can be produced. However, if desired, the partition  84  can be extended into and even beyond the passage in the nozzle base  80  to minimize merging of the two charges of icing. 
         [0038]    In the case in which the charges of icing on both sides of the partition  84  are the same, a decorative twisting pattern can still be produced if the nozzle opening is offset slightly from its axis of rotation, or formed with serrations or in another configuration that imparts a non-circular shape to the extruded string of icing. 
         [0039]    When the charge of icing is exhausted, the applicator can be taken apart by rotating the screw  42  in the direction such that it is withdrawn from the tube  76 , and removing the pump section  14  from the drive unit  12 . The tube can then be recharged with icing. Alternatively, the nozzle  82  can be disconnected from the nozzle base  80 , and the nozzle base can be disconnected from the tube  76 . The components can then be cleaned and stored for future use. 
         [0040]    In the alternative embodiment illustrated in  FIG. 4 , the drive unit and pump are identical to the drive unit and pump of the embodiment in  FIGS. 1-3 . The nozzle assembly, however, comprises two nozzles offset from the axis of rotation, and angularly adjustable so they can be oriented for discharge of flowable material in oblique relation to, a discharge axis which is the same as the axis of rotation of the nozzle assembly. 
         [0041]    The nozzle base  92 , includes a pair of articulating adapters  94  and  96 , each connected by a ball joint to a fitting  98  threaded onto the tube  76 . Nozzles  100  and  102  are removably connected respectively to the adapters  94  and  96 . 
         [0042]    In the embodiment of  FIG. 4 , two separate strings of icing are extruded and directed obliquely toward the discharge axis. As the strings are extruded, they wind about each other, forming a twisted pair of strings. The shape of the twisted pair can be adjusted both by adjusting the directions of the nozzles and by controlling the rate at which the applicator moves relative to the cake being decorated. If desired, the two nozzles can be different from each other. For example one of them can be configured to produce a string of icing narrower than the string of icing produced by the other. 
         [0043]    In a third embodiment, illustrated in  FIGS. 5-7 , a fitting  104 , which is part of a nozzle base, has three passages (not shown), each communicating with one of three ball-joint sockets  106 ,  108  and  110 . These ball joint sockets are equidistant from a rotation axis and uniformly spaced from one another about the rotation axis. Angularly adjustable adapters, and nozzles, similar to those shown in  FIG. 4  are connected to the fitting  104 . 
         [0044]    A three part partition  112 , having a Y-shaped transverse cross-section composed of three parts  114 ,  116  and  118  as shown in  FIG. 6 , is fixed to, and extends proximally from, fitting  104 . The screw  120  is divided into three parts by longitudinal slots  122 ,  124  and  126 , which form a Y-shaped opening configured to receive the Y-shaped partition. A piston assembly  128 , formed at the end of the screw, is also composed of three segment-shaped pistons  130 ,  132  and  134 . In this embodiment the partition divides the interior of the tube  76  into three equal, segment shaped cylinders, which can contain three different kinds of icing, each cylinder communicating with a different nozzle. 
         [0045]    As shown in  FIG. 7 , in the drive unit, rotating member  136  is similar to the rotating member in  FIG. 3  except that it has three inwardly directed protrusions  138 ,  140  and  142  fitting respectively into slots  122 ,  124  and  126 , for rotating the screw while allowing longitudinal movement of the screw. 
         [0046]    In  FIG. 8 , the three nozzle applicator  144 , is shown applying icing to a cake  146  rotating on a turntable  148 . The icing  150  has a rope-like shape, consists of three strings wound about one another. 
         [0047]    As the several versions of the applicator can utilize common parts, manufacturing costs can be minimized. Moreover, the interchangeability of parts makes it possible for the user to convert easily from a single nozzle version to a multiple nozzle version. For example, the single nozzle embodiment of  FIG. 1  can be converted to a two nozzle version as in  FIG. 4  simply by replacing the nozzle and nozzle base of  FIG. 1  with the nozzles and nozzle base of  FIG. 4 . Similarly the three nozzle embodiment of  FIGS. 5-9  can be converted to a single nozzle version by replacement of the three nozzles and nozzle base with a single nozzle and a nozzle base having a Y-shaped partition but only a single nozzle opening. 
         [0048]    Conversion of an applicator having two cylinders and a flat partition to an applicator having three cylinders and a Y-shaped partition can be carried out by replacing the nozzles, the nozzle base, the screw and the rotating drive member. 
         [0049]    The applicator makes it easy to apply twisted strings of icing uniformly, and can be refilled and cleaned readily 
         [0050]    Numerous modifications can be made to the apparatus described. For example, where the interior wall of the tube  76  is in the form of a circular cylinder, the nozzle assembly and partition can be mounted for rotation relative to the tube while the tube does not rotate. If the tube rotates, its inner wall does not need to be in the form of a circular cylinder and can have any of various cross-sectional shapes as long as the interior is cylindrical. In that case it is only necessary to provide for rotation of the tube by means of suitable bearings. It is also possible to achieve simultaneous rotation of a nozzle assembly and axial translation of pistons in a configuration in which the pistons are in their own parallel cylinders separate from one another. 
         [0051]    The apparatus can also be readily converted, by a simple interchange of parts, to a non-rotating icing applicator having an unslotted screw and no partition. 
         [0052]    In other variations, a variable speed motor can be used, and the applicator can be operated by a battery rather than by line current. The screw can be replaced by a screw having a different thread pitch to change the rate at which icing is discharged from the nozzle or nozzles. 
         [0053]    Various other modifications can be made to the apparatus describe without departing from the scope of the invention as defined in the following claims.