US 2445657 A
Description (OCR text may contain errors)
J y 0, 1948- P. G. BENNETT 2,445,557
TOOTHBRUSH Filed May 8, 1945 au 6.39am 17,
923 3;; M-W m/ dliiys Patented July 20, 1948 UNITED STATES PATENT OFFICE TOOTHBRUSH 7 Paul G. Bennett, Boston, Mass. Application May 8, 1945, Serial No.592,543 1 Claim. (01. -167) My invention relates to toothbrushes.
The invention has among its objects the provision of a toothbrush having a body the portion of which that carries the bristles or the like is resilient for operating on the teeth in an improved manner.
In the drawings:
Fig. 1 is a. plan of a toothbrush according to the invention;
Fig. 2 is an elevation of the toothbrush according to Fig. 1; and
Fig. 3 is a more or less diagrammatic illustration of the manner in which the toothbrush may be applied to the human mouth to operate on the inner and outer sides of the row of teeth.
Referring to the drawings, the body of the toothbrush comprises a rigid handle portion l and a resilient brush portion 2, the latter carrying the bristles 3 for forming a brush. As shown, the brush portion 2 is longitudinally curved so that the operating face afforded by the free ends of the bristles of the brush is normally concave longitudinally thereof.
The brush portion 2 of the body of the toothbrush is preferably made of resilient material, for example vulcanized rubber, and as shown is secured to the handle portion l of the body by the skived cemented joint indicated at 5. The construction of the portion 2 is such that when the brush is pressed against the outer side of a row of human teeth it may be readily flexed into a position of lesser curvature, for example as indicated at 2a, and when pressed against the inner side of such row may be flexed into a position in which its normal concave side becomes convex as indicated at 2b. To facilitate the securing of such flexure the portion 2 preferably, but not necessarily, is progressively tapered in thickness toward its outer free end. Preferably the degree of resiliency of the body portion of the brush and the degree of stiffness of the brush are such that the desired fiexure of the brush may be secured without collapsing the bristles when the outer end portion of the brush is pressed against the teeth so long as that portion amounts to a substantial fraction of the length of the brush, which fraction conveniently, but without limitation thereto, may be about one-quarter the length of the brush.
Preferably the longitudinal curvature of the brush portion 2 of the body of the toothbrush is such that when the brush is applied to the outer or convex side of the row of teeth I (Fig. 3) said body portion will be bent into a position of lesser curvature as indicated for example at 20. in Fig.
3 which corresponds to the dotted line position of the part 2 indicated at 2a in Fig. 2. Consequently, assuming the bristles are of substantially the same length throughout the longitudinal extent of the brush, the curvature of the brush body portion 2 is preferably approximately that of the greatest curvature of the row of teeth so that the bristles when operating on the convex or outer side of the row will by flexure of the portion 2 always conform to the teeth throughout substantially the entire length of the brush. In cases where it is desired to have the bristles of progressively changing length, say for example shorter at the mid portion of the length of the brush than at its opposite end portions, the curvature of the brush body portion 2 may be correspondingly changed to secure the same effect as when the bristles are of substantially the same length throughout the longitudinal extent of the brush.
The toothbrush is applied to the inner or concave side of the row of teeth in the usual manner so that only the bristles toward the front end of the brush are operative. Under these conditions the body portion 2 flexes so that the normally convex side thereof becomes concave, the portion 2 under these conditions assuming a position indicated for example at 2b in Figs. 2 and 3. However, by reason of this flexure of the portion 2, a greater lengthwise extent of the brush will be effective to operate on the teeth than in toothbrushes heretofore constructed. For example, with the present toothbrush about two-thirds the length of the brush may simultaneously operate on the inner side of the teeth, while with toothbrushes as ordinarily constructed but about one-quarter the length of the brush may simultaneously operate on the teeth. Furthermore with toothbrushes as heretofore constructed the same may operate on the inner concave side of the row of teeth only by collapsing a large extent of the bristles, but with the present brush because of the fiexure of the 'body portion 2 such collapsing of the bristles does not occur.
It will be observed that, in respect to securing the above described action when operating on the inner or concave side of the row of teeth, the flexible body portion 2 of the brush could be straight and still flex to secure such action. This however could be secured in such case only at a sacrifice of the advantage secured by a flexible curved body portion 2 when operating on the outer side of the row of teeth.
It will be understood that within the scope of the appended claim wide deviations may be made 3 from the form of the invention described without departing from the spirit of the invention.
A toothbrush having a handle, the latter at one end thereof carrying a longitudinally urved bendable elongated part tapered toward its free end formed of a single piece of resilient material presenting continuous longitudinal exterior surfaces for the entire length of said part on all sides thereof, said part being provided at its 10 concave side with a row of projecting brush bristles distributed longitudinally thereof; the degrees of curvature and taper of said part, the resiliency of said material, and the stiffness of'said bristles being such as to cause said part to bend 15 1,327,807
transversely and resiliently press said rcw" of bristles against the convex side of :a row of human teeth of lesser degree of curvature than said part when said bristles are applied thereto, and said part to bend to cause itsconcave side to become 20 REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date "758,764 Macleod May 3, 1904 759,490 Yates May 10, 1904 Burleigh June 13, 1920 "1,466,723 Izawa Sept. 4, 1923 1,494,448 Sookne May 20, 1924 1,928,328 Carpentier Sept. 26, 1933 2,254,365 Griffith et a1 Sept. 2, 1941