Interdental cleaners and methods for making same

A method of making interdental cleaners includes forming a slug by extruding material in a direction of extrusion to form a first slug portion having a generally rectangular first cross-section and a second slug portion having a tapering second cross-section that extends away from the rectangular first cross-section. The method also includes stamping the slug substantially perpendicular to the direction of extrusion to form a plurality of cleaner blanks. The stamping forms the first slug portions into handle portions of the cleaner blanks, and the second slug portions into shaft portions of the cleaner blanks. The shaft portions include two pairs of converging surfaces that taper toward each other to define a point. The method also includes attaching cleaning members to the ends of the shaft portions.

BACKGROUND

The present invention relates generally to interdental cleaners and methods for making interdental cleaners.

Interdental cleaning is a principal element of oral hygiene. The spaces between teeth allow plaque and other debris to collect which can harm the gums and teeth. Dental floss is often used to eliminate such debris from the interdental spaces. Dental floss is often cumbersome to use because it requires two hands for proper manipulation of the floss into and out of the interdental spaces. Dental floss is also problematic for patients with certain types of dental appliances (e.g., braces or dental bridges) because it may be difficult or impossible to manipulate the floss into or around the appliance. The interdental cleaner alleviates these shortfalls because it may be manipulated into interdental space otherwise unreachable by traditional flossing methods using a single hand. Because interdental cleaners are generally single-use items, it is beneficial to employ fast, efficient, and cost effective processes for their manufacture.

SUMMARY

In some aspects, the invention may provide a method for making interdental cleaners that includes forming a slug by extruding material in a direction of extrusion, which includes forming a first slug portion having a first cross-section and a second slug portion having a second cross section that is different from the first cross-section. The extruded slug is also formed to define a midplane that is substantially parallel to the direction of extrusion. The method also includes stamping the slug in a direction of stamping that is substantially normal to the midplane to produce a plurality of cleaner blanks. Each cleaner blank is formed to include a handle portion and a shaft portion, and is formed to be oriented along the midplane with the shaft portions extending substantially perpendicular to the direction of extrusion. The method also includes attaching a cleaning member to each shaft portion.

In other aspects, the invention may provide a method of making interdental cleaners that includes forming a slug by extruding material in a direction of extrusion, which includes forming a first slug portion having a first cross-section and a second slug portion having a second-cross section that is different from the first cross-section. The slug is formed to define a midplane and such that the second slug portion defines a first pair of converging surfaces that converge toward the midplane. The method also includes stamping the slug in a direction that is substantially normal to the midplane to form a plurality of cleaner blanks. Each cleaner blank is formed to include a handle portion formed from the first slug portion and a shaft portion formed from the second slug portion. Stamping the slug also includes forming each shaft portion to include a second pair of converging surfaces. The method also includes attaching cleaning members to a portion of the shaft portion.

In still other aspects, the invention may provide a method of making interdental cleaners that includes forming a slug by extruding material in a direction of extrusion to form a first slug portion having a first cross-section and a second slug portion adjacent the first slug portion and having a second cross-section that is different from the first cross-section. The method also includes stamping the slug substantially perpendicular to the direction of extrusion to form a plurality of cleaner blanks. The stamping includes stamping the first slug portion to form handle portions of the cleaner blanks, and stamping the second slug portion to form shaft portions of the cleaner blanks. The method also includes attaching cleaning members to the shaft portions.

DETAILED DESCRIPTION

FIGS. 1-3illustrate a first embodiment of an interdental cleaner10a. The interdental cleaner10aincludes an elongated, substantially rigid central rod12, which in the illustrated construction is or includes a metallic (e.g., steel) wire. The rod12may be formed of, among other things, one or more braided metallic wires, solid metallic wires and/or extruded polymers or plastics, such as monofilament nylon. The interdental cleaner10aincludes cleaning member14positioned at a first end16of the central rod12. The cleaning member14is generally formed from a plastic material that is suitable for use in the mouth and that is sufficiently hard to provide cleaning of interdental spaces, but sufficiently soft so as not to damage the gums of a user. For example, in some constructions, the cleaning member14is formed of a thermoplastic elastomer, although other materials may also be used. The cleaning member14is generally formed of a material that is softer than the rod12.

The cleaning member14is formed into a shape suitable for cleaning interdental spaces. Such shapes may include, but are not limited to, conical, cylindrical, pyramidal, rectangular or polygonal in nature. In the illustrated construction, the cleaning member14is substantially conical in shape and includes a central, generally cylindrical body portion18that receives and thereby overlies the first end16of the central rod12. The cleaning member14also includes a plurality of bristles22that extend radially outwardly from the body portion18. The bristles22vary in length from a shortest length adjacent a distal end of the cleaning member14, to a longest length adjacent a proximal end of the cleaning member14, thereby providing the overall substantially conical shape. The substantially conical shape allows the cleaning member14to effectively clean interdental spaces of varying sizes dependent upon the extent to which a user inserts the cleaning member14into the interdental space.

In the illustrated construction, the cleaning member14is coupled to the central rod12by over molding and/or adhesion. For an overmolding operation, the first end16of the central rod12is positioned in a mold cavity that defines the desired shape (e.g., conical) of the cleaning member14. The cleaning member material (e.g. thermoplastic elastomer) is then injected into the mold cavity and allowed to cool around the first end16. An adhesive may also be applied to the first end16before the molding process to provide additional coupling between the cleaning member14and the first end16. Alternatively, the cleaning member14may be molded individually and the first end16of the central rod12may subsequently be inserted into the body portion18. Such insertion may be manual or automated, and may also involve or include the application of a suitable adhesive to one or both of the cleaning member14and the central rod12to provide coupling adhesion therebetween.

The interdental cleaner10aalso includes a handle26coupled to a second end28of the central rod12. The handle26is generally formed from a plastic (e.g., polypropylene, including glass-filled polypropylene, and/or nylon) having a hardness that is equal to or greater than the plastic used to form the cleaning member14. In the illustrated construction, the handle26is substantially flat and elongated to provide suitable surfaces for grasping by a user. The handle26may also be formed into any other suitable shape (e.g., cylindrical) provided that the handle26is appropriately sized so as to avoid interfering with a users access to the interdental spaces while also providing for effective gripping and manipulation of the device.

Like the cleaning member14, the handle26is generally coupled to the central rod12by overmolding and/or adhesion. For the overmolding operation, the second end28of the central rod12is inserted into a mold cavity that defines the shape of the handle26(e.g., flat and elongated). The mold cavity is then injected with the desired plastic for the handle26and allowed to cool. Adhesives may also be applied to provide extra coupling between the end30and the handle26. Alternatively, the handle26may be molded individually, and the central rod12may be inserted into the handle26after the molding process. Insertion of the central rod12may be manual and/or automated. As illustrated inFIGS. 1-3, the central rod12is exposed between the handle26and cleaning member14, thereby creating a central portion of the interdental cleaner that is of reduced cross section to facilitate interdental cleaning.

FIGS. 4-6illustrate a second embodiment of an interdental cleaner10b, in which the handle26includes a sheath portion34which extends along at least a portion of the central rod12toward the cleaning member14. The sheath34covers and in some instances provides additional structural support to the central rod12. In the illustrated construction, the sheath34extends to a location that is near but not directly adjacent to the cleaning member18. In other constructions the sheath34may extend from the handle26to the cleaning member18to completely cover the central rod12. The sheath34is generally integrally formed with the handle26, and, like the handle26, may be coupled to the central rod12by overmolding and/or adhesion, as discussed above. In other constructions, the sheath34and the handle26may be formed separately and subsequently coupled to one another and to the central rod12. It should be appreciated that substantially any sequence of assembly may be utilized during the manufacture of the handle26, sheath34, and the central rod12.

FIGS. 7-9illustrate a first embodiment of an extrusion (FIG. 7) that is formed into a third embodiment of an interdental cleaner10c(FIG. 9). The interdental cleaner10cis formed by stamping cleaner blanks38from an extruded slug42of an extrudable material that may include, for example, polypropylene (including glass-filled polypropylene) and/or nylon. The extruded slug42includes a substantially uniform thickness. After stamping, the cleaner blanks38are subsequently overmolded with or otherwise coupled to a cleaning member44. As shown inFIG. 7, the cleaner blanks38are preferably stamped out of the slug42in a pattern devised to minimize waste material. Preferably, waste material that remains after stamping of the cleaner blanks38is recycled for subsequent extrusion and stamping into additional cleaner blanks38.

As shown inFIGS. 8 and 9, each cleaner blank38includes a handle portion46and a shaft portion50. The handle portion46and shaft portion50substantially correspond in shape and size to the handle26and central rod12if the interdental cleaners10aand10bdiscussed above with respect toFIGS. 1-6. After the cleaner blanks38are stamped from the extruded strip42, finishing methods such as tumbling, polishing, or deburring may be employed to remove flash and/or sharp edges from the cleaner blanks38. Once the cleaner blanks38are stamped and, if necessary, finished, cleaning members44are formed on or coupled to the distal ends of the shaft portions50using cleaning member materials and overmolding or adhesion operations similar to those described above with respect to the cleaning members10a,10b.

FIGS. 10-13illustrate a second embodiment of an extrusion (FIG. 10) that is formed into a fourth embodiment of an interdental cleaner10d(FIGS. 12 and 13).FIG. 10illustrates an extruded slug60of extrudable material that may include, for example, polypropylene (including glass-filled polypropylene) and/or nylon. The slug60is extruded in the direction of the arrow N to produce a midplane P and includes a plurality of sections64that extend across the width of the slug60and that include similar cross-sectional geometry. The cross-sectional geometry of each section64includes a relatively thicker central portion66, and relatively reduced thickness end portions68. Each section64is ultimately formed into an individual interdental cleaner10d.

In the illustrated construction, the slug60includes a substantially constant cross section in the direction of extrusion N to simplify the extrusion process. As material is extruded, the slugs60are cut to length in increments that substantially correspond to the length of the finished interdental cleaner, although additional material may be included to facilitate handling during trimming and/or other manufacturing processes not necessarily explained herein.

FIG. 11illustrates the slug60after a stamping process. After being extruded and/or cut to length, the slug60undergoes a stamping process which removes material from the slug60to form each section64into an individual cleaner blank70. Each cleaner blank70includes a handle portion72and a shaft portion74. Formation of the shaft portion74may include forming a tapered portion that reduces in cross section as it extends away from the handle portion72. Formation of the handle portions72may include the addition of grips and/or the tapering of certain edges so as to better suit the grasping process and/or enhance aesthetic appeal. Other possible alterations to the handle portions72may include the addition of a company logo76.

In the illustrated construction, the stamping process also removes material from between adjacent handle portions72to define a separation slot78and a plurality of connecting tabs80. The slot78and the tabs80are configured to allow a plurality of interdental cleaners10cto be packaged and handled as a single, continuous strip, while providing for the relatively quick and simple separation of individual interdental cleaners10dby breaking of the tabs80. The slots78and tabs80are configured so that this can be accomplished without damaging the individual cleaners10dand with the use of a cutting device. For example, the tabs80are formed in the reduced-thickness end portions68of the slug sections64.

FIGS. 12 and 13illustrate strips of completed interdental brushes10d. After the above-described extrusion and stamping processes, cleaning members82are formed on or coupled to at least the distal ends of the shaft portions74using cleaning member materials and overmolding or adhesion operations similar to those described above with respect to the cleaning members10a, and10b. The cleaning members82are generally formed of a material that is softer than the material that forms the cleaner blanks. For example, the cleaning members may be formed of a thermoplastic elastomer. The cleaning members82may be substantially conical in shape (FIG. 12), substantially rectangular (FIG. 13), or substantially any other cross-sectional shape. Although not specifically illustrated, the cleaning members82may also include various arrangements of bristles, such as those discussed above with respect to the cleaning members10a, and10b. Similarly, the cleaning members82(and bristles, if any) may include a textured surface that may or may not incorporate abrasives (e.g. pumice) to provide additional debris removal capability for the cleaning members82. It should also be appreciated that other or additional manufacturing processes may also be employed to prepare the respective interdental cleaners10cfor commercial use. Possible flash and/or other remnants of the manufacturing process may be removed by tumbling, chemical cleaning, buffing, or other processes.

FIGS. 14-17illustrate a third embodiment of an extrusion (FIG. 14) that is formed into a fifth embodiment of an interdental cleaner10e(FIGS. 16 and 17).FIG. 14illustrates an extruded slug88that is extruded in a direction of extrusion F to define a midplane P. Whereas the slug60ofFIG. 10is extruded in a direction that is substantially parallel with the shaft portions74of the resultant interdental cleaners10d, the slug88is extruded in the direction F that is substantially perpendicular to the shaft portions74of the resultant interdental cleaners10e, for reasons discussed further below. The slug88includes a first portion90having a substantially uniform, e.g., rectangular, constant cross section, and a second portion92having a cross section that tapers toward a distal end of the second portion92that is opposite the first portion90. The second portion92also defines a first pair of converging surfaces91(only one of the surfaces91is shown inFIG. 14) that face away from one another and converge toward the midplane P. Although each of the illustrated first pair of converging surfaces91is substantially planar, one or both of the converging surfaces may also be curved along all or a portion of its length.

As shown inFIG. 15, the slug88is subjected to a stamping process similar to that of the slug60, to thereby form cleaner blanks93that each include a handle portion94formed from the first portion90, and a shaft portion96formed from the second portion92. The stamping process employed for the slug88may be similar to that discussed above with respect to the slug60, and may similarly provide slots78and tabs80that allow individual interdental cleaners10eto be snapped off of a continuous strip of interdental cleaners10ewithout otherwise damaging the interdental cleaners10eand without the use of a cutting device. As illustrated, the shaft portion96of each cleaner blank93tapers from a wide end97adjacent the first portion90to a narrow, distal end99opposite the wide end97. The taper of each shaft portion96is defined by a second pair of converging surfaces95that face away from one another and that, like the converging surfaces96, converge toward one another from the wide end97to the narrow distal end99. Although a majority of each of the illustrated second pair of converging surfaces95is substantially planar, one or both of the converging surfaces95may also be curved along all or a portion of its length.

As illustrated inFIG. 16, after the cleaner blanks93have been formed by the extruding and stamping operations, cleaning members100are formed on or coupled to the shaft portions96, generally on or adjacent to the distal ends99, using cleaning member materials and overmolding or adhesion operations similar to those described above, thereby forming interdental cleaners10e. It should also be appreciated that each of the manufacturing methods, materials characteristics, shapes, and bristle configurations of the various cleaning members discussed above may also be utilized for the cleaning members100of the interdental cleaners10e.

In the embodiment ofFIGS. 14-17, because the shaft portions96are not parallel with either the direction of extrusion or the direction of stamping, the shaft portions96may be formed with two pairs of converging surfaces (e.g., the first pair of converging surfaces91formed by extrusion, and the second pair of converging surfaces formed by stamping). This allows the distal end99of the cleaner blank93, and thus the distal end98of the resulting interdental cleaner10e(FIG. 16) to include a more sharply-defined pointed end relative to the distal ends of the interdental cleaners10cor10d, which generally taper in a single direction (e.g., the direction of stamping).