US 3739416 A
A hygienically shielded rotary toothbrush having a brush shield comprising a substantially open structural network to reduce the deposit and transfer from person to person of remnant toothpaste, bacteria and organic matter. Internal switches on the motor casing are triggered by a protruding nub affixed to the interior of the shaft shield to actuate the motor to drive the rotary brush either in a clockwise or in a counterclockwise direction.
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United States Patent 1191 a 111 3,739
Kurachi June 19 1973 HYGIENICALLY SHIELDED ROTARY 3,161,899 12/1964 Poizat 15 23 TOOTHBRUSH  Inventor: Masami Mike Kurachi, 311 High Primary f Roberts Street, Modesto, Calm 95350 Attorney- Norman E. Re1tz and Hlubert E. Dubb  Filed: Jan. 17, 1972 ] Appl. No.: 218,302  ABSTRACT A hygienically shielded rotary toothbrush having a brush shield comprising a substantially open structural network to reduce the deposit and transfer from person Fi i c 15/25 24. 310/50 to person of remnant toothpaste, bacteria and organic e ea matter. Internal switches on the motor casing are trig- References Cited gered by a protruding nub affixed to the interior of the shaft shield to actuate the motor to drive the rotary UNITED STATES PATENTS brush either in a clockwise or in a counterclockwise di- 2,275,247 3/1942 Cavanagh 15/23 rection.
2,310,626 2/1943 Gold 15/23 2,840,837 7/1958 Gustems 15/23 8 Claims, 5 Drawing Figures Pmmwwm n Fig. 3
TO MOTOR AND POWER SOURCE F la 4 I-IYGIENICALLY SHIELDED ROTARY TOOTHBRUSH This invention relates to a motor powered rotary toothbrush and more specifically to a hygienically shielded rotary toothbrush having an internal switch for reversing the direction of rotation of the rotary brush.
Rotary toothbrushes have often been advanced as the solution to the need for an effective personal means of brushing teeth as part of an overall preventive dental care program but has not achieved widespread commercial acceptance. Previous rotary toothbrushes have been plagued by the fact that they have been unwieldy and have required bulky shields to protect the brush from scraping the inside of the cheek or sensitive gum areas. They have also been difficult to clean and have been a source of the collection and transfer of germs from person to person since most shields were cup shaped and can harbor remnant toothpaste, bacteria, and organic matter. This transfer would occur even if every user had his own brush since the cup shape shields would never be completely cleaned and would come in contact with the clean brushes.
It is known that it is highly desirable to have a rotary toothbrush that can reverse its direction so that the brushing may be carried out in a direction away from the gum regardless of the location of the teeth or whether the user is right or left handed. A solution to this problem has been suggested, alternatively, as the provision of dual rotating brushes which operate in opposite directions as in U.S. Pat. No. 3,008,162 issued to J. Koblanski, or the provision of an external switch to control the direction of rotation as in U.S. Pat. No. 2,310,626 issued to J. Gold and in U.S. Pat. No. 3,451,086, issued to E. B. Burgett. These solutions to the problem either involve a complex mechanical arrangement or require the user to use a second hand to control the switch. Also, the existence of external switches makes it difficult to construct the motor casing in a waterproof manner, a necessity since the toothbrush will be continually exposed to water.
It is therefore an object of this invention to provide a rotary toothbrush having an internal switch for controlling the direction of rotation of the rotary brush which can be operated by the same hand that holds the toothbrush, e.g., by the thumb and forefinger.
It is a further object of this invention to provide a rotary toothbrush wherein the shield is capable of being readily snapped in and out of position so that both the brush and shield may be conveniently cleaned.
It is a still further object of this invention to provide a hygienically shielded rotary toothbrush wherein the brush shield comprises a structural network which is substantially open so that the shield is less likely to have remnant toothpaste or bacteria collect on its inner surface, so that the brush shield is easier to clean, and so that the brush shield is less unwieldy.
It is an additional object of this invention to provide a hygienically shielded rotary toothbrush wherein the shield is composed of a substantially open structural network so that the turbulant flow of saliva and toothpaste is not interupted by the presence of a solid shield to achieve more effective brushing.
BRIEF DESCRIPTION OF THE DRAWINGS For a more thorough understanding of the above objects of the present invention reference may be had to the drawing which is incorporated herein and made a part of this specification and in which:
FIG. 1 is a front perspective view of the rotary toothbrush illustrating the motor casing, shaft shield, hygienic brush shield and rotary brush;
FIG. 2 is a side perspective view of the rotating brush assembly including rotary brush and hygienic brush shield;
FIG. 3 is a side perspective view of the hygienic brush shield in the snapped open position;
FIG. 4 is a cut-away perspective view of the internal switch of the rotary toothbrush of the present invention; and
FIG. 5 is a section view of the switch taken along line 5-5 of FIG. 4.
SUMMARY OF THE INVENTION The hygienically shielded rotary toothbrush of the present invention permits the user to conveniently insert the rotary brush and hygienic brush shield in his mouth. The brush shield is only slightly longer than the length of the brush and conforms closely to somewhat less than half of its cylindrical shape. The shield consists of a structural networks substantially open so that remnant toothpaste, bacteria, and organic matter does not collect on its inner surface and preferably has a solid bottom portion to prevent splattering downwardly towards the motor casing. The hygienic shield can be snapped in place or snapped open so that both the brush and shield may be cleaned. In a preferred embodiment the hygienic shield is held in place adjacent the rotating brush by means of grooves on the upper portion of the shaft shield which conform tightly to the shape of the legs of the brush shield.
The direction of rotation of the rotary brush may be readily changed by rotating the shaft shield with respect to the motor casing. If the rotary toothbrush user holds the motor casing in his palm he may readily rotate the shaft shield with respect to the motor casing by using his thumb and forefinger. Maximum rotation in a counterclockwise direction forces a nub affixed to the interior of the shaft shield against a pressure switch to initiate rotation of the rotary brush in the counterclockwise direction. Rotation of the shaft shield in a clockwise direction forces an additional nub against a second pressure switch to initiate the rotation of the rotary brush in the clockwise direction. In another embodiment a single nub is rotated against the pressure switches to initiate rotation in the two directions.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1 it can be seen that the hygienically shielded rotary toothbrush 10 of the present invention comprises a motor casing 11 with a shaft shield 9 fitted in coaxial alignment thereupon. The shaft shield 9 consists of cylindrical strip 25 which overlaps motor casing 11, conical section 13, sleeve 14, and brush shield sleeve 15.
A shaft 18 extends beyond the: upper end of shaft shield 9. Shaft 18 is disposed to receive the stem 19 of rotary brush 20 in a detachably attachable manner so that every user can have his own personal brush. A watertight seal is achieved by washer 24 as shaft 18 extends downwardly into shaft shield 9. Shaft 18 extends into motor casing 11 and is attached to the motor encased therein.
While the motor of the rotary toothbrush of the present invention may be battery operated or may operate directly from line voltage the preferred embodiment incorporates a rechargeable battery or power cell which is enclosed within motor casing 11. The rechargeable battery or power cell is conveniently charged when the rotary toothbrush is not in use by means of an external electrical connector which may be inserted within socket 12. Typically, the electrical connector is positioned in a permanent upright position so that the rotary toothbrush may be placed on said connector and stored in a stable vertical attitude.
Hygienic brush shield 21 is shown in detail in FIG. 2 to be a semicylindrical structure having a substantially open surface area as indicated by openings 23. It is small, lightweight, and easily insertable into the mouth of the user. The normal pattern of use of mechanical toothbrushes is to interchange rotary brushes so that every person in a family has his own brush. With conventional rotary toothbrushes having brush shields to protect the inside of the cheek and exposed gum tissue, remnant toothpaste, bacteria and organic material can readily collect on the inner surface area of the brush guard. The substantially open hygienic shield 21 of the present invention reduces the possibility of the transfer of such deposited materials from one brush to another. Also, the skeletal structure permits the brush shield to be more readily cleaned.
The hygienic shield 21 of the present invention may be snapped out of the protective position as shown in FIG. 3. In the snapped open position the inside surface area of hygienic brush shield 21 is readily accessible and may easily be cleaned. By examination of FIGS. 2 and 3 it can be seen that, in the preferred embodiment, hygienic brush shield 21 is held in place in groove 22 due to the match between the contours of the inner surface of the legs of lower portion 17 of hygienic brush shield 21 and groove 22. Brush shield sleeve 15 and hygienic brush shield 21 are typically constructed of resilient thermoplastic materials so that the legs of lower portion 17 of hygienic brush shield 21 may be snapped over the edges of groove 22. To facilitate the movement of hygienic guard 21, in an alternative embodiment, connecting rivets 16 are spring biased to hold the legs of lower portion 17 normally against brush shield sleeve 15, at the same time allowing the legs to move outwardly a slight distance as they are moved over the edges of groove 22. The lower portion 17 is preferably of solid construction to prevent water and saliva from splashing downwardly towards the shaft shield 9 and motor casing 11. Other snap-in means, of course, may also be used.
The rotary brush incorporated in the toothbrush of the present invention is capable of rotating in both directions. This is highly desirable since it is proper dental practice to brush away from the gum. Thus, brushing of upper or lower teeth or brushing by right or left handed users can be properly carried out. To actuate the motor which drives shaft 18 and thus rotary brush 20 it is necessary, then, to have a three pole switch: off, (the direction of rotation and counterclockwise direction of rotation (the direction being determined by looking at the toothbrush from the brush end). Prior art rotary toothbrushes have utilized external switches or switches which have required operation by a hand other than the one which holds the tooth-brush. External switches, of course, are a potential entry point through which moisture may enter the motor casing.
The unique internal switching means of the rotary toothbrush of the present invention is shown in FIGS. 4 and 5. Nubs 26 and 41 are affixed to the interior of cylindrical strip 25 of shaft shield 9 and ride, respectively, in slots defined by ledges 31 and 32 formed in the upper rim of motor casing 11. If shaft shield 9 is rotated to its counterclockwise limit of rotation (denoted by extended radius 33) nub 41 will press against leaf spring 35 to close an electrical connection between electrical junction 29 (the terminus of lead 29) and electrical junction 30 (the terminus of lead 40). For convenience of the user these leads can be wired to the motor to actuate it in the counterclockwise direction.
In the like manner, if shaft shield 9 is rotated to its clockwise limit of rotation (denoted by extended radius 34) nub 26 will press against leaf spring 36 to close an electrical connection between electrical junction 27 (the terminus of lead 38) and electrical junction 28 (the terminus of lead 37). For convenience the triggering of this switch can actuate the motor in a clockwise direction. Both leaf switches are permanently attached to the inside of the upper rim of the motor casing 11.
As seen in FIG. 5 protruding nubs 26 and 41 may move through only a limited arc. At the ends denoted by extended radii 33 and 34 the motor is actuated to drive the motor in a specific direction. At all intermediate points the rotary brush does not rotate. The friction fit of shaft shield 9 over motor and power source casing 11 requires that a moderate force be used to rotate the protruding nubs. Thus, the nubs can not be accidentally jarred into either side to inadvertantly actuate the rotary brush. It is clear that any pressure switch may be used in place of the leaf spring switch illustrated. Additionally, a single nub riding in a single channel may be used so long as the two switching means are positioned at opposite ends of the slot defined by the ledge in the upper rim of motor casing 11. Or a variable speed reversable motor could be actuated by a series of pressure switches positioned at specific intervals along a slot in the upper rim of the motor casing. If more than two pressure switches were used it would be desirable to have a means to hold the shaft shield 9 at the specific positions of the pressure switches, e.g. notches along the slot to accommodate the protruding nub.
While specific embodiments have been described in this application for Letters Patent the present invention is intended to be limited by the scope and spirit of the appended claims.
1. A hygienically shielded rotary toothbrush comprising, a motor casing and motor means encased therein, a shaft attached at one end to said motor means and extending beyond the upper end of said motor casing, a shaft shield aligned coaxially with said motor casing, the lower end of said shaft shield fitting over and overlapping said upper end of said motor casing in a pressure fit, said shaft extending through said shaft shield and beyond the upper end thereof, a rotary brush detachable attachable with the upper end of said shaft, a hygienic brush shield attached to the upper end of said shaft shield and rotatable between a snapped-in position at which said brush shield protectively shields an approximately semi-cylindrical volume of said brush and a second open position at which both sides of said brush shield and said rotary brush are readily accessible for cleaning, at least two pressure switches affixed to slot means configured in the upper end of said motor casing, one of said switches serving to actuate said motor to drive said brush in a clockwise direction and another of said switches serving to actuate said motorto drive said brush in a counterclockwise direction, said switches being actuated by nub means protruding from the interior of said overlapping lower end of said shaft shield, said nub means riding in said slot means.
2. A toothbrush as in claim 1, wherein the legs of said hygienic brush shield are contoured to fit in grooves on the upper end of said shaft shield to permit said brush shield to rest firmly in said snapped-in position, said brush being rotated to said open position by twisting said legs over the edges of said groove.
3. A toothbrush as in claim 2, wherein said hygienic brush shield is attached to the upper end of said shaft shield by spring biased rivets which normally hold said legs in said groove and which permit said legs to be spread apart to slip over the edges of said groove when said hygienic brush shield is rotated from said snappedin position to said open position.
4. A toothbrush as in claim 1, wherein a rechargeable battery or power cell is housed within said motor casing to power said motor, said rechargeable battery or power cell communicating with an external connector through a socket configured in said motor casing.
5. A toothbrush as in claim 1, wherein the pressure switches are affixed to opposite ends of said slot means and are actuated by said nub means.
6. A toothbrush as in claim 1., wherein additional switches are affixed to said slot to provide a control for a variable speed motor.
7. A toothbrush as in claim 1, wherein said hygienic brush shield is detachably attachable to the upper end of said shaft.
8. A toothbrush as in claim 1, wherein said slot means includes a first slot and a second slot configured in the upper end of said motor casing and wherein said nub means includes a first nub and a second nub protruding from the interior of said overlapping lower end of said shaft shield, said first nub riding in said first slot and said second nub riding in said second slot, one of said two pressure switches being affixed in said first slot and serving to actuate said motor to drive said brush in a clockwise direction and the other of said two pressure switches being affixed in said second slot and serving to actuate said motor to drive said brush in a counterclockwise direction.
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