This invention relates to toothbrushes and it is the general object of the invention to provide a toothbrush having a bristle section the contour of which can be altered at the will of the user.
In the ordinary toothbrush the bristles have a fixed contour because of the rigidity of the handle and the parts which carry the bristles.
Some toothbrushes are made with a convex tooth engaging portion while others have concave contours. For proper cleaning of the outside of the teeth the bristle section should be concave, whereas the inner surfaces of the teeth are cleaned best with a bristle section which is convex. It is an important object of our present invention to provide a toothbrush the bristle section of which is flexible and provided with means to be manipulated by the user whereby the bristles may be made either convex or concave. In this way a single toothbrush can give the degree of cleaning which heretofore has been possible only with two brushes of different forms.
It is another object of our present invention to extend through the bristle section of the brush a normally curved member, such as a wire, which is rotatable in the section and is sufficiently strong to overcome the resistance to bending on the part of the bristle section. We have found it convenient to anchor the rotatable member in some part of the handle so that relative turning of the handle with respect to the bristle section will cause turning of the curved member or wire within the bristle section to change its shape. In practice we have found it convenient to anchor the rotatable member in the end of the handle but we do not wish to be limited to this construction, since the handle as a whole may be made rotatable with respect to the bristle section as will be pointed out hereinafter.
Most toothbrushes at the present time are made with a handle composed of Celluloid or similar material of sufficient thickness to be substantially rigid. In its broader concept our invention includes the provision of a bristle section which shall be flexible enough to respond to the forces exerted by the curved member, but in the practical application of our invention we have found several ways in which the bristle section can be made sufficiently flexible even though Celluloid or similar material be used as an anchorage for the bristles. In this connection other objects of our invention include structural changes in the usual bristle section which will lessen its rigidity, these changes in one form of the invention involving transverse grooves part way through the usual bristle section. We are not limited to this means for rendering the bristle section flexible, however, and in other instances have cut the bristle section into a number of small bristle carrying units which are connected together by a flexible binder or holder the form of which can be changed by the curved member when the latter is rotated. We realize that various means can be employed to render the bristle section flexible and in the broader aspects of our invention do not wish to be limited necessarily to the specific forms described hereinafter.
With these and other objects in view which will appear as the description proceeds, our invention resides in the combination and arrangement of parts hereinafter described and set forth.
In the accompanying drawing, where three forms of the bristle section and two forms for anchoring the rotatable member are shown, Fig. 1 is a plan view of the preferred form of our invention, Fig. 2 is a side elevation of the brush shown in Fig. 1 with the bristle section concave and an intermediate step of changing the formn of the bristle section is indicated in dotted lines, Fig. 3 is a view similar to Fig. 2 but in which the bristle section is convex, Fig. 4 is a view of the rotatable unit as it would appear if removed from Fig. 2, Fig. 5 is an enlarged vertical section on line 5-5 of Fig. 1, Fig. 6 is a vertical section on line 6-6 of 85 Fig. 5, Fig. 7 is a detailed view of the first modification of the flexible bristle section, Fig. 8 is a view similar to Fig. 7 but showing the second modification of the bristle section, and Fig. 9 is a view similar to Fig. 2 but showing a modification of the rotatable member which alters the contour of the bristle section.
Referring to the preferred form of the invention shown in Figs. 1 to 6, the brush B is shown as having a body 10 made of Celluloid or similar material and of the usual form. At the end of the body section 10 are a plurality of separate units II which may be made of the same material as the body 10 and except as set forth hereinafter have the same general cross sectional area. As shown in Fig. 2 each unit is provided with bristles 12 which for purposes of illustration are shown to be all of the same length, although this is not an essential feature. Certain bristles 13 may if desired be carried directly by the handle II.
In order to connect the units II I provide a hollow binder 15 having parallel spaced sides IS which are connected at their ends as indicated in Fig. 1. This binder may be made of thin spring steel material and is embedded as set forth in Fig. 2 in the outer parts of the individual sections I . The units II are rigid but considered collectively provide a series of bristle carrying parts which are rendered flexible by reason of the binder 15.
Extending through the body II is a longitudinal bore 20 which is in alignment with a series of similar bores 21 in the units II. A steel wire 22 shown in Fig. 4 of slightly less diameter than the bores 20 and 21 is located within the bores and has the right end thereof as indicated in Fig. 4 normally curved as at 23. This curve is permanent and may have any desired radius of curvature, although we have found that a curve as illustrated in the drawing is quite satisfactory. The left end of the wire 22 is broadened as at 25 and is embedded in an extension 26 of the handle the cross section of which may be substantially the same as the body 10. The end 25 of the wire is non-circular and is therefore held against angular motion with respect to the end 26 so that when the latter is turned the wire will turn with it in the bores 20 and 21. If desired the end 26 may have a rib 28 to fit into a complementarily formed transverse groove 29 in the end of the body 10, the purpose of the rib and groove being to maintain the end 28 normally in the position shown for instance in Fig. 3 with respect to the body I . We find that the wire is possessed of a slight resillence which is sufficient to hold the rib in the groove. The right end of the wire as shown in Fig. 1 may preferably fall short of the outer unit 30 of the bristle carrying section. It will also be seen from Fig. 5 that the wire is above the plane of the binder II and is located between bristles.
In using our toothbrush the bristle section may be concave as shown in Fig. 2 in full lines due to the fact that the end 23 of the wire is curved upwardly. When it is desired to change the contour of the bristle section the end 20 will be given a half turn with respect to the body 10, passing through the dotted line position shown in Fig. 2 and ultimately reaching the position shown in Fig. 3, where the bent end 23 extends downwardly as indicated in dotted lines in Fig. 4 to cause the bristle carrying units to curve in the opposite direction to make the tooth engaging surface of the bristles convex, As shown in Fig. 7 the bristle section 40 is integral with the handle 41 but is weakened by a series of transverse slots 42 which extend part way through the bristle section. The Celluloid or other material of which the brush in this first modification form is shown possesses sufficient resilience so that when weakened as indicated in Fig. 7 it will respond to the changes exerted by the curved end 23 of the wire when the latter is turned, The second modification shown in Fig. 8 has grooves 45 on one side of the bristle section 41 while other grooves 47 are on the opposite side, the bristle section being integral with the body section 48 as is the case with the first modificatlon. The transverse slots 45 and 47 weaken the bristle section sufficiently so that it can respond to the curved end 23 of the wire In a 2,254,365 manner similar to that described in connection with Fig. 7.
In the forms of the Invention already described we contemplate the use of an end 21 for the handle 10. In Fig. 9, however, we show a body 50 for the handle section in the right end of which is embedded a broadened or non-circular end 51 of a wire 52 which is shorter than that shown in the previously described forms of the invention and has a normal curvature which is similar to the curve 23 in that it extends In a direction away from the axis of the handle. The bristle carrying section 55 may be rendered flexible either in the manner illustrated in igs. 7 or 8 to render it flexible. In ig. 9 the section ii is indicated in dot and dash lines without illustrating any particular method for rendering it flexible. In this form a turning of the handle iS with respect to the bristle section 55 will change the contour of the tooth engaging surface of the bristles in a manner similar to that already described. The advantage of the structure shown in Fig. 9 is that the wire is shorter and it is not necessary to provide the handle with a long bore extending entirely therethrough.
Returning for a moment to the preferred form shown in Figs. 1 and 3 it will be seen that the left end of the binder 15 is secured to the handle section 10, and it is by this connection that the several units are held to the handle by the section provided through the binder 1I. In this form of the invention, as well as in those shown in Figs. 7 and 8, we find that the curved end 23 tends by its shape to hold the handle section or end 28 in position. Any tendency on the part of the wire to move longitudinally to the left in the bore of the handle 10 is resisted by the normal curve 23. This relation makes it unnecessary to connect the wire directly to the flexible bristle carrying section of the brush. We find that the curved end 23 has an inherent resilience permitting it to pass through the straight form shown in dotted lines in Fig. 2, but the resistance to . bending offered by the binder 15 is less than that offered by the curved end 23 and the latter is therefore able to overpower the binder and require the latter to take the form of the curve 23. The net force acting to curve the bristle section is of course the force with which the o5 curved end resists straightening less the smaller force which the flexible section offers to bending. When the wire has been given a quarter turn as suggested in dotted lines in Fig. 2 the _ curved end 23 exerts a force which is directed 65' transversely of the length of the bristles, but this force is nullified in the preferred form by the sides of the binder 15 and in the first and second modifications by those portions of the bristle section which are uncut and remain integral with the handle.
From the foregoing it will be seen that we have provided a toothbrush having a flexible bristle carrying section through which extends a member having a normal curve and wherein rotation gs of the member with respect to the bristle section alters the shape of the latter. It will further be seen that there are various ways in which the bristle section can be rendered flexible either by the use of binder 15 in connection with detached separate bristle carrying units as in the preferred form, or by weakening the bristle section when the latter is made integral with the handle. It will also be seen that the wire or .curved member can either be fastened to an end of the handle separate from the latter as for instance in the form of the invention shown in Fig. 1, or the wire may be anchored in the end of the handle adjacent to the bristle section.
Having thus described our invention it will be seen that changes and modifications may be made there by those skilled in the art without departing from the spirit and scope of the invention and we do not wish to be limited to the details herein disclosed, but what we claim is: 1. In a toothbrush, a handle section, a member secured to the section and having a resilient normally curved end projecting from the section, a series of separate bristle carrying units each with a bore to receive the said curved end of the member, and a flexible binder secured to the handle and to each of the units to connect the latter to the handle section, said bristle units and binder forming a bristle section and the binder capable of bending on itself in a plane substantially parallel to the bristles to make said bristle section either concave, flat, or convex with respect to the bristles, relative turning of the sections causing the curved end of the member to turn in the units, the binder preventing lateral bending of the bristle section relatively to the handle section and causing the curved member to straighten as it turns in the units, continued turning of said curved member after becoming. straight permitting the curved member again to assume its normally curved form to give the bristle section a different shape.
2. In a toothbrush, a handle section, a group of bristle carrying units, said units separate from the handle and from each other, each unit having a bore therein, a flexible connector secured to each of the units and also secured to the handle section, said flexible connector bendable on itself in a plane substantially parallel to the bristles only and resisting lateral bending relatively to the handle section, and a wire secured to the handle section and having a resilient normally curved part extending loosely through said bores, a half rotation of the sections with respect to each other causing the curved part of the wire to bend on itself in said plane to change the form of the connector and units, the connector in preventing lateral movement of the units causing the resilient curved part of the wire to straighten during the first part of said half rotation and said curved part of the wire returning to normal curved form during the latter part of said half rotation to produce a change in the shape of the connector and group of units relatively to the handle section, the resistance to bending offered by the connector being less than the resistance to bending offered by the curved end of the wire.
3. In a toothbrush, a handle section, a group of bristle carrying units separate from the handle and from each other, a substantially flat metallic flexible connector secured to the units and to the handle. said flexible connector bendable on itself in a plane substantially parallel to the bristles only and resisting lateral bending relatively to the handle section, each unit having a bore therethrough, and a wire secured to the handle section and having a resilient normally curved end extending through the bores, relative turning of the handle section through a half rotation with respect to the units causing the curved end of the wire to rotate within said units, the connector in preventing lateral movement of the units causing the resilient curved part of the wire to straighten during the first part of said half rotation and said curved part of the wire returning to normal curved form during the latter part of said half rotation to produce a change in the shape of the connector and group of units relatively to the handle section.
4. In a toothbrush, a handle section, a bristle , section integral therewith and provided with a series of bristles, a bore extending through the handle and bristle sections, the bristle section being rendered flexible by a series of transverse grooves therein, said bristle section bendable on lo itself only in a plane substantially parallel to the bristles because of said transverse grooves and capable of being concave, flat, or convex relatively to the bristles, and a wire secured to the handle section and rotatable in said bores and having the resilient normally curved part extending into the bristle section, rotation of the wire in the bore causing the flexible bristle section to straighten the curved part of the wire and thereby cause the bristle section to become 2o flat with respect to the bristles, the wire by continued rotation acting due to its resilience to assume normally curved form and bend the bristle section to a form curved oppositely to that which it had relatively to the bristles at the beginning of the rotation.
5. In a toothbrush, a bristle section carrying bristles, a series of transverse grooves to weaken the resistance of the bristle section to bending and render the same flexible, said bristle section bendable on itself only in a plane substantially parallel to the bristles because of the direction of said grooves, said bristle section having a bore therein, a wire having a resilient normally curved part extending into the bore of the bristle section and normally bending said bristle section in a given direction relatively to the bristle, and means to turn the wire a half rotation in the bore to cause a change in the shape of the bristle section to curve the latter in a direction relatively to said bristles in a direction opposite to said given direction, the bristle section by bending only in said plane causing the curved part of the wire to straighten during the rotation and said curved part thereafter resuming normally curved form to cause the aforesaid bending of the bristle section.
6. In a toothbrush, a handle section having a bore therethrough, a bristle section connected to the handle section and being flexible to bend on itself in substantially a single plane with respect to the handle section, an end section at that end of the handle section remote from the bristle section, the bristle section having a bore therein aligning with the bore of the handle section, and a wire extending through the aligned bores and having one end thereof secured in the end section and having the other end thereof resilient and normally curved and extending into the bore of the bristle section, a half rotation of the end section with respect to the handle section causing a half rotation of the curved end of the wire within the bore of the bristle section to change the shape of the latter with respect to the handle section by bending in said single plane, said bristle section causing the curved end of the wire to straighten during the first part of the half rotation to set up a stress in said end of the wire, and continued turning of the wire permitting the curved end of the wire to reassume its normally curved form and thus bend the bristle section.
7. In a toothbrush, a flexible section having bristles projecting from a surface thereof, said section being bendable on itself more easily in one plane than in any plane oblique to said one plane to make said surface either concave, fiat, or convex relatively to said bristles, a resilient normally curved member extending longitudinally of and rotatable relatively to the flexible section and so related to the latter as to change form r with respect to curvature when the form of the flexible section changes with respect to curvature, and means to turn the member relatively to the section, turning of the member with respect to the flexible section straightening the member due to the bending of the flexible section in said one plane and continued turning of the member permitting the latter to reassume its normally ucurved form, the change of form of the flexible member from curved to straight form and thereafter back to curved form during a turning of the member relatively to the flexible member in the same direction causing the latter to change the type of its curvature relatively to the bristles.
EDWARD E. GRIFPiTH. ELUIOTT M. STORY.