Disposable toothbrush assembly
atent [1 1 [111 3,879,139 1 Apr. 22, 1975 DISPOSABLE TOOTHBRUSH ASSEMBLY [75] Inventors: Rulon R. Dahl, West .lordon;.  
 Garnett O&#39;Brien Garrett, Salt Lake City, both of Utah [73] Assignee: Developmental Design, Inc., Salt Lake City, Utah [22] Filed: Feb. 25, 1974 [21] Appl. N0.: 445,519  
 Related [1.8. Application Data [63] Continuation-in-part of Ser. No. 363,232. May 23, 1973, abandoned, which is a continuation-in-part of Scr. No. 239,154, March 29, 1972, abandoned.  
 [52] US. Cl 401/135; 15/22 [51] Int. Cl A46b 11/02 [58] Field of Search 401/132-135, 401/149, 150, 156, 171, 176, 182; 15/22, 176  
 [56] References Cited UNITED STATES PATENTS 1,947,720 2/1934 Laub 401/8 2,090,144 8/1937 Palimeri ct a1 401/135 3,181,189 5/1965 Leyden 15/22 R 3,256,031 6/1966 Fillweber 15/22 R X 3,536,410 10/1970 Wargoe 401/132 FORElGN PATENTS OR APPLICATIONS 512,130 7/1956 ltaly 401/176 Primary Examiner-Lawrence Charles Attorney, Agent, or Firm-Lynn G. Foster [57] ABSTRACT A disposable toothbrush assembly comprising a disposable head having a hollow base which is open at one transverse end, slightly tapered along the longitudinal side wall edges and includes a plurality of bristles each of predetermined cross-sectional configuration molded as an integral part of the base and projecting from the top surface thereof in an upward direction, the bristles defining a chimney along which toothpaste initially contained within the head is extruded after passing through a pre-cut port in the top wall of the head, the pre-cut port being closed by a hinged valve cover during storage prior to use. The toothbrush assembly also comprises a handle initially assembled during storage prior to use so as to extend a short distance into the head at the mentioned transverse opening, the handle having a slightly enlarged leading end, sized and shaped so as to spread the longitudinal side walls of the head during insertion, and including at the interface between the enlarged leading end and the adjacent remainder of the handle a notch along each side into which toothpaste flows during insertion to create a firm handle-retaining seal. The handle portion adjacent the mentioned enlarged leading end is sized and shaped so as to serve as a guide insuring proper alignment during insertion. An extrusion channel is defined along the top of the leading end and the alignment or guide portions of the handle to accommodate flow of toothpaste to the central port of the head after the leading end of the handle has passed the port site.  
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 DIS POSABLE TOOTHBIRUSH ASSEMBLY BACKGROUND Continuity FIELD OF INVENTION This invention relates to the cleaning of teeth and more particularly to a disposable toothbrush assembly.  
 PRIOR ART Brushes have long been used for cleaning and polishing teeth, and like purposes. However, there have been many disadvantages to such brushes and their use heretofore. The storage of toothbrushes between use periods presents contamination problems. Also, for sanitary purposes, each person must have his own toothbrush and, in large families, and-the like, substantial storage space is required and use of the wrong toothbrush becomes a frequent problem. In addition, it is customary to provide toothpaste in squeeze tubes which require additional storage space and, due to individual preferences, it is usually necessary for a family to store several such tubes. Furthermore, if toothpaste tubes are squeezed adjacent the dispensing end, rather than adjacent the remote end, it is difficult to dispense all of the toothpaste from the tube and much of the contents of the tube is wasted. Another practice, which falls in the same category, is that of failing to replace the cap on the toothpaste tube, which allows the tooth paste in the dispensing neck of the tube to harden and prevents dispensing of the remainder of the contents. When travelling, the problems relating to conventional toothbrushes and toothpaste are increased. Toothbrushes and toothpaste tubes often become misplaced and lost. Moreover, since toothbrushes are often wet and retain some toothpaste in their bristles, special containers or compartments must be provided, in suitcases and the like, to prevent the toothbrushes from soiling or staining clothing or other articles packed therewith.  
  Numerous attempts have been made heretofore to overcome these problems and to provide an approach insuring fresh breath, reduced cavities and brushing capability without carrying the conventional brush and paste container. However, none of the prior art devices has been entirely satisfactory. Many attempts have been made to combine a toothbrush with a toothpaste dispenser. Unfortunately, many of the prior art devices have been complicated and expensive to produce. Loss of flavor and/or freshness from the toothpaste with passage of time is likewise a problem when a toothbrush and toothpaste are in combination. Other prior art devices have been difficult to use, while still others have been extremely wasteful and often messy. Many of the prior art devices have failed to overcome one or more of the problems stated above, and may have introduced additional problems.  
 BRIEF SUMMARY AND OBJECTS OF THE INVENTION The mentioned disadvantages of the prior art are overcome or substantially alleviated with the present invention and a toothbrush assembly and related method are provided, which assembly is simple and economical to produce and use, assures sanitation during storage and transportation, prevents waste and messy loss of toothpaste, reduces the storage space required, overcomes the problems of mix-up or loss, preserves the flavor and freshness of the toothpaste even when stored for a protracted period of time and insures superior cleaning of the teeth when used.  
  The advantages of the present invention are preferably attained by providing a toothbrush assembly and related methods, the toothbrush assembly having a telescopic handle initially extending a short distance through a transverse opening into the base of a head formed of pliable plastic with memory containing a supply of toothpaste in the base adjacent external bristles which extend from the top face of the base about a central pre-cut but initially covered central port. Toothpaste is automatically extruded from its encasement in the base through theport, along a chimney formed by surrounding bristles and across the top of the bristles upon insertion of the handle fully into the base. The interior of the base is longitudinally convergently tapered in the direction of handle insertion and the leading end of the handle is slightly larger than the cross-sectional area of the base. Thus, as the handle is axially advanced into the hollow interior of the base, being guided by the side edges of the handle adjacent but downstream of the leading end of the handle, the base is expanded by but retracts behind the enlarged leading end of the handle with a toothpaste seal being formed between the handle and the base along the side edges at a location where the handle is reduced adjacent the enlarged leading end. The more the handle is advanced into the base the more tightly it is retained against inadvertent removal during use, yet advancement creates little resistances. An hydraulic extrusion channel at the upper face of the handle directs toothpaste back to the extrusion port once the leading end of the handle has passed the port. An extrusion channel seal is located inside the head and substantially fills the channel, preventing the paste from extruding down the channel and escaping onto the handle.  
  With the foregoing in mind, it is a primary object of the present invention to provide an improved disposable toothbrush assembly for cleaning teeth, and related methods.  
  Another object of the present invention is to provide a toothbrush assembly comprising a base and telescopically insertable handle which is simple and economical to produce and use.  
  Another object of the present invention is the provision of a disposable toothbrush assembly with toothpaste encased within the base of a head which preserves flavor and freshness, avoids contamination and minimizes waste.  
  A further paramount object of the present invention is to provide a disposable toothbrush assembly having a head the base of which comprises a pre-cut and initially covered central extrusion port to preserve toothpaste freshness but permits ready extrusion when use is desired.  
  A further significant object of the present invention is the provision of a disposable toothbrush assembly comprising a novel head with a transverse opening and interior walls which are slightly convergently tapered away from the opening.  
  A further significant object of the present invention is the provision ofa novel disposable toothbrush assembly comprising a head fabricated of material which will expand under force of handle insertion and return to its original dimensions because of the memory of the material.  
  It is a further and important object of the present invention to provide a disposable toothbrush assembly comprising a handle the leading end of which is enlarged in respect to the head into which it is telescopically forcibly inserted.  
  A further paramount object of the present invention is to provide a novel disposable toothbrush assembly comprising a handle comprising at least one reduced diameter slot adjacent an enlarged leading end whereby an hydraulic seal is formed with toothpaste initially contained within a head.  
  A further primary object of the present invention is to provide an improved handle for a disposable toothbrush assembly wherein a central portion of the handle serves as a guide to insure aligned insertion of the handle into a head, from which toothpaste is extruded.  
  Another principal object of the present invention is the provision of a novel handle for a disposable toothbrush assembly wherein an upper hydraulic extrusion channel is provided for back flow of toothpaste to a central extrusion port in a head thereof.  
  Another valuable object of the present invention is the provision of a novel head as part of a disposable toothbrush, the head having an internal seal at an extrusion channel in a handle to prevent loss of paste at the extrusion channel site.  
  These and other objects and features of the present invention will be apparent from the following detailed description, taken with reference to the accompanying drawings.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective representation of a presently preferred disposable toothbrush assembly with the handle placed in a transverse opening of the base of a disposable head for storage and shipment prior to use;  
  FIG. 2 is an exploded perspective representation of the disposable toothbrush assembly of FIG. 1;  
  FIG. 3 is a crosssectional view taken along lines 3-3 of FIG. 2;  
  FIG. 4 is a fragmentary plan view taken along lines 4-4 of FIG. 2;  
  FIG. 5 is a cross-sectional view taken along lines 55 of FIG. 2;  
  FIG. 6 is a fragmentary bottom plan view taken along lines 6-6 of FIG. 5;  
  FIG. 7 is a longitudinal fragmentary cross section of the head and part of the handle of the disposable toothbrush assembly of FIG. 6 with the handle inserted into the base of the head up to the central extrusion port;  
  FIG. 8 is a fragmentary cross-sectional view similar to FIG. 7 with the handle further inserted into the head of the base illustrating the reverse flow of toothpaste to the extrusion port; and  
  FIG. 9 is a cross-section view of one bristle of the head of the disposable toothbrush assembly of FIG. 1.  
 DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT In that form of the present invention chosen for purposes of illustration, FIGS. 1 and 2 show a disposable toothbrush assembly, generally designated 10. The assembly 10 comprises primarily a disposable head 12 and a disposable handle 14. The head 12 is preferably fabricated as one piece using injection molding tech niques and comprises a hollow, generally box-shaped base 16 which in turn comprises a trailing transverse opening 18, generally rectangular in configuration, a bottom wall 20, atop wall 22 and spaced longitudinally directed convergently tapered side walls 24, the taper being away from the opening 18 to the leading trans verse wall 26. The top and bottom walls 20 and 22 may also be slightly convergently tapered toward wall 26. In reference to FIG. 4, which illustrates the convergence, it is presently preferred that the taper a being on the order of 20.  
  The hollow cavity, with the exception of a short distance at opening 18 within the base 16 is filled with a slug of toothpaste 28. It is preferred that the slug of toothpaste 28 be inserted into a series of heads 12 by causing a predetermined amount of toothpaste from a large supply to be displaced through the opening 18. Naturally, the toothpaste is pliable and extrudable as initially placed within the hollow of the base 16 and is preserved in that condition in a manner hereinafter described.  
  A plurality of bristles 30 are integrally formed with and extend upwardly from the top face 22 of the base 16. The preferred cross-sectional configuration of the bristles is illustrated in FIG. 9 whereby proper up and down strokes with the brush, once properly assembled with the handle so as to provide toothpaste across the top of the bristles 30, will insure maximum bristle resistance and superior scrubbing action. It has been found that bristles of the configuration shown in FIG. 9 produce improved dental hygiene which is superior to many toothbrushes currently on the market and intended for repeated rather than disposable use.  
  The top wall 22 of the base 16 comprises a rectangular opening or port 32. Naturally, the port 32 could be otherwise configurated. The port 32 is closed by a hinged valve cover 34 and it is preferred that the hinged valve cover 34 be created by die punching the port 32 along three of the four sides after the head 12 has been integrally injection molded. The die cutting technique must result in negligible space 36 at the rectangular interface 36 between the hinged valve cover 34 and the port 32. In this way, it has been found that the freshness (absence of dryness and retention of flavor) of the toothpaste is preserved and yet the extrusion of the paste from the cavity of the base 16 is readily accomplished without resistance. Upon handle insertion, the toothpaste 28 contained within the hollow space 16 is immediately extruded upward through the port 32 up the chimney 38 defined by the surrounding bristles and across the top of the bristles 30.  
  It is important that the plastic material from which the head 12 is formed be pliable and have considerable memory so that a stretching effect, hereinafter explained, during handle insertion will result in a return by the material from which the head is fabricated to its initial dimensions in order to create stability between the head 12 and the handle 14 following insertion and to create an improved seal between the head and handle during and following insertion.  
  The handle 14 preferably comprises an elongated relatively thin one piece item the trailing end 40 of which is intended to be held in the hand of the user. The forward portion 42 of the handle 14 is intended to be inserted through the opening 18 into the hollow of the base 16.  
  A sealing compound, such as paraffin or gelatin or other suitable biologically inert non-bonding compound may be initially interposed between the leading end portion of the handle and the interior wall surfaces of the base adjacent the opening 18 to further aid in preserving freshness. The same approach may be used to seal the interface 36 between the port 32 and the closure hinged valve cover 34.  
  An enlarged abutment 44 is intended to function as a stop upon reaching the opening 18, and 45 is a relief to aid in the comfort of the user by allowing the lips of user to close on handle. The forward portion 42 of the handle 14 comprises an enlarged leading end 46, a necked down portion 48 and a reduced sized guide portion 50. With reference to FIG. 6, it is presently preferred that the distance T which is one-half the difference in transverse dimension between the enlarged leading end 46 and the guide portion 50 be on the order of 0.00l0.003 of an inch. The transverse dimension across necked down portion 48 is slightly less than the transverse dimension at 50.  
  An extrusion chamber 52 extends along the top surface of the forward portion 42 of the handle 14 inclusive of the enlarged end 46, the necked down portion 48 and the guide portion 50 for a specific purpose hereinafter more fully explained.  
  Disregarding the channel 52, the enlarged leading end 46 defines a cross-sectional area slightly larger than the cross-sectional area at opening 18 of base 16. The principal difference in the respective crosssectional area is caused primarily because of the greater transverse dimension at leading end 46. Thus, when the leading end 46 of handle 14 is placed in the hollow of base 16 at opening 18, a spreading effect of the base side walls occurs as best illustrated in FIG. 6, which is a bottom plan view. As a result, the yieldable plastic material from which the head 12 is made is displaced outwardly by the leading end 46 as illustrated at locations 56, thereafter clings tightly to the sides 58 of the enlarged head 46 and later returns, because of the memory of the material from which the head 12 is made, to essentially the original dimensions when reaching the necked down and guide portions 48 and 50.  
  To prevent paste loss at channel 52, an extrusion channel seal 53 is provided along the inside of top wall 22 of base 16. The seal 53 projects from wall 22 so as to entirely fill the channel 52 and firmly engage all surfaces forming the channel 52.  
  As insertion increases, retention is primarily by plastic flowing (memory). Thus, the side walls 28 of the base 16 and the enlarged side flanges 58 of the leading end 56 will flow into and rest at notches or necked down portion 48, creating a seal which prohibits loss of paste along the exposed portion of the handle 14 and aids in preventing inadvertent handle removal. As the handle 14 is further inserted, the base 16 at opening 18 will contiguously grip the guide portion 50 of the handle 14, serving to insure axial alignment between the head 12 and the handle 14 during insertion. Also, because of the taper at wall 24, an additional retaining force at locations 56 is created between the leading end 46 of the handle 14 and the head 12, the magnitude of which increases as insertion continues. Once insertion has been completed, firm retention against inadvertent separation is insured.  
  The forward portion 42 of the handle 14 comprises side wall flanges 60 which extend both up and down along the leading end 46, the necked down portion 48 and the guide portion 50, although the thickness of the flange varies as illustrated. A front abutment flange 62 running transverse of the handle 14 at the leading end 46 serves to prevent toothpaste extrusion during insertion along the bottom of the handle.  
  The handle at the insertion segment 42 thereof accommodates a feedback extrusion of toothpaste along the extrusion channel 52, once the leading end 46 of the handle 14 has been displaced past the central extrusion port 32, insuring controlled extrusion of essentially all of the toothpaste encased within the base 16 for use in brushing the teeth, thereby minimizing waste. Contrast FIG. 7 and 8.  
  It is presently preferred that the hinged valve cover 34 be cut or otherwise positioned prior to filling of the hollow of the base 16 with toothpaste, the hinged valve cover 34 being held by suitable retaining structure in the illustrated position during such filling, following which the hinged valve cover 34 has been found to be self-retaining prior to handle insertion. Also, as illustrated in FIG. 1, it is essential for the preservation of taste freshness that the handle 14 be inserted a short distance through the opening 18 of the base 16 for storage, shipment and the like prior to use.  
  The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.  
  What is claimed and desired to be secured by U.S. Letters Pat. is:  
 1. A disposable toothbrush assembly comprising:  
 a head formed from yieldable plastic material having memory comprising a hollow base defined by side walls, a bottom wall, a top wall and an end wall but open at the other transverse end, said head comprising a plurality of bristles extending from the top wall of the base, a port centrally disposed in said top wall of the base interconnecting the bristles with the interior of the base, and a removable closure substantially filling the port;  
 a quantity of tooth cleansing or treating material disposed within and filling essentially all of the hollow of the base except a short distance adjacent said base opening, the tooth material being contiguous with the closure;  
 a separate handle formed of substantially rigid plastic material having an enlarged leading end portion sized to enlarge the crosssectional area of the base by expanding the yieldable plastic material as the handle is telescopically inserted into the hollow of the base, the handle comprising a reduced size guide portion adjacent the leading end portion sized to allow yieldable plastic to flow and lock behind the enlarged section to engage the side walls of the base to maintain axial alignment between the base and handle during said insertion, memory of the base material constricting the base crosssectional area into said engagement, the handle comprising a tooth material extrusion chamber extending across the leading end portion and the guide portion whereby the tooth material flows back to the central port along the extrusion chamber after the leading end portion of the handle passes the extrusion port during insertion.  
  2. A disposable toothbrush assembly as defined in claim 1 wherein the hollow interior of the base has a cross-sectional area which progressively converges between the opening and the end wall.  
  3. A disposable toothbrush assembly as defined in claim 2 wherein the converging cross-sectional area is caused at least in part by tapered side walls of the base.  
  4. A disposable toothbrush assembly as defined in claim 1 further comprising slot means interposed between the leading end and the guide portions of the handle whereby a seal and lock between the handle and the base occur at the slot means due to plastic flow of the base.  
  5. A disposable toothbrush assembly as defined in claim 1 wherein the extrusion chamber is defined in part by two upwardly extending flanges each simultaneously engaging the top wall and one side wall of the base.  
  6. A disposable toothbrush assembly as defined in claim 1 wherein the leading end portion of the handle comprises two side wall engaging flanges, each said flange also engaging the top wall and the bottom wall, and a transverse flange engaging the bottom wall and bridging between the two side wall engaging flanges.  
  7. A disposable toothbrush assembly as defined in claim 1 further comprising a biologically inert sealing compound initially interposed between the leading end portion of the handle and the interior wall surfaces of the base adjacent the opening.  
  8. A disposable toothbrush assembly as defined in claim 1 wherein each bristle of the head is injection molded and has a diamond-shaped cross section having a side-to-side dimension substantially greater than the longitudinal dimension when viewed in cross section.  
  9. A disposable toothbrush assembly as defined in claim 1 further comprising a seal projecting from the inside of the base and substantially filling the extrusion chamber.  
  10. A disposable toothbrush assembly as defined in claim 1 wherein the converging cross-sectional area is caused at least in part by tapered top and bottom walls of the base.  
  11. A disposable toothbrush assembly as defined in claim I further comprising a biologically inert sealing compound initially interposed between the extrusion port and the closure.  
  12. A method of making a disposable toothbrush, the steps of:  
 molding a plastic head of yieldable synthetic resinous material having a hollow base open along one transverse end and bristles projecting from one wall of the base outwardly;  
 removing part of the one wall of the base to form an extrusion port central of the array of bristles; covering the extrusion port with a close tolerance closure;  
 holding the closure within the port and simultaneously filling the hollow interior of the base with toothpaste, except for a minority volume juxtaposed the opening;  
 placing the leading end of an elongated handle into the opening to engage and spread walls of the base causing an expansion in cross-sectional area of the hollow of the base, whereby the leading end is sealed and retaomed to the walls of the base, for storage prior to use;  
 advancing the leading end of the handle into the hollow of the base perpetuating said sealed and retained condition and extruding paste from the hollow of the base through the extrusion port and on to top of the bristles, at a point in time when use is desired.  
  13. A method as defined in claim 12 wherein the advancing and extruding comprises initially forcing paste in the hollow of the base forward toward the extrusion port and later backward along extrusion chamber of the leading end of the handle to the extrusion port, once the leading end has been displaced beyond the extrusion port.