US 3088148 A
Description (OCR text may contain errors)
y 1963 M. MORET TOOTHBRUSH ATTACHMENT Filed April 1'7, 1961 INVENTOR T%S w dn o a N M R O L E T T w? M Y M United States Patent 3,088,148 TOOTHBRUSH ATTACHMENT Michel Moret, Chenes Bougeries, Geneva, Switzerland,
assignor to Etahlissement AESUP, Vaduz, Liechtenstein, a firm of Liechtenstein Filed Apr. 17, 1961, Ser. No. 103,482 2 Claims. (Cl. 15-22) This invention relates to a toothbrush attachment, and particularly such an atachment for a motor unit having a rotationally oscillatory shaft.
In U.S. Patent No. 2,917,758, an electrically-operated toothbrush is described comprising a motor unit having a shaft on the end of which a brush head is mounted. The shaft is rotationally oscillated in use, and the corresponding movement of the brush bristles efiects a brushing of the teeth in the longitudinal direction thereof.
in order to permit the electrically-operated toothbrush to be used by different members of the family, and to permit replacement of Worn brush heads, it is desirable to arrange the brush portion for convenient attachment to the motor unit and removal therefrom. Further, for hygienic reasons it is desirable for the brush attachment to include all portions normally inserted in the mouth. This may be accomplished by providing an attachment having a stem of sufficient length, with the bristles at one end and a coupling at the other end adapted for attachment to the shaft of the motor unit.
For greatest usefulness, the coupling should fulfill several requirements. It should permit convenient attachment and removal, and be adapted to rotationally oscillate the brnsh stern in a positive manner without undue wear. It should also resist forces tending to detach the brush from the motor unit when the bristles are presssed against the teeth during cleaning. Finally, it is advantageously designed so that it can be formed by molding in plastic material, so that the attachment unit can be economically manufactured without metal portions which would contact the teeth during the cleaning operation and give rise to discomfort or injury.
The present invention provides a toothbrush attachment which meets the foregoing requirements.
In the drawings:
FIG. 1 is an overall view of the motor unit with the toothbrush attachment in place;
FIG. 2 is an enlargement of a portion of FIG. 1, with the attachment removed from the motor unit shaft;
FIG. 3 is an end view of the toothbrush attachment, taken from the coupling end;
FIG. 4 is a view at right angles to FIG. 2, with the attachment in position on the motor unit and portions shown in cross-section; and
FIG. 5 is an end view of a modified coupling, with the cooperating portion of the motor shaft shown in crosssection.
Referring to FIGS. 1-4, a motor unit is shown in the form of a handle having internal structure for imparting rotational oscillation to shaft 11. The motor unit may be, for example, of the construction shown in the aforesaid US. patent.
The end portion 12 of shaft 11 is formed with a noncircular cross-section, and as here shown the cross-section is substantially rectangular. The narrow sides 13 may have a slight curvature. A transversely-extending pin 14 is provided. Advantageously this is located on one of the wide sides of the shaft end, and spaced a substantial distance from the tip of the shaft. The shaft end may be of plastic material and, for strength, may be molded or otherwise aflixed to a steel core 15, as shown in FIG. 4.
The toothbrush attachment comprises a stem 21 on 3,088,148 Patented May 7., p 19 63 "ice one end of which are laterally-extending bristles 22. At the other end is a coupling, generally designated 23. Stem 21 may be of plastic material, such as nylon, with the bristles set in in known manner, and the coupling 23 formed by molding. It is desirable for the mid-portion of stem 21 to be fairly slender so that the brush may readily be inserted in the mouth. However, to provide adequate strength in coupling 23, that end of the stem is enlarged.
The coupling comprises a socket 24 of non-circular cross-section adapted to mate with the motor unit shaft end 12. As here shown, socket 24 has a substantially rectangular cross-section. =A longitudinally-extending slot 25 is formed in the wall of the socket, with its open end 26 at the open end of the socket. Opposed transversely-extending recesses 27, 27' are formed in the sides of the slot near the open end 26 thereof, to provide a seat for pin 14 when in mating position.
The dimensions of the slot and recesses are predetermined to yieldably secure the toothbrush attachment on the motor unit shaft when in mating position. As shown, the Width of slot 25 is less than that of pin 14, and opening 26 is flared so that the pin can readily enter the slot and be yieldably secured in recesses 27, 27. Due to the resiliency of the material of which the stem is made, the stem 21 can readily be pushed into mating engagement with the motor unit shaft, and removed therefrom. By enlarging the coupling end, the walls are adequately thick to permit repeated attachment and detachment without injury to the coupling, and to exert adequate force on pin 14 to retain the attachment in coupled position.
The non-circular cross-section of the socket effectively transmits rotational oscillation from shaft 11 to stem 21, Without requiring the sides of the slot to withstand rotational forces. Thus, the forces due to rotational oscillation do not tend to spread the slot walls and allow the attachment to slip off.
When the toothbrush is in use, the bristless 22 will be pressed against the teeth, and consequently there will be a lever action at the coupling end 23. In order to prevent this lever action from detaching the stem, it is ad vantageous to locate slot 25 in a longitudinal plane through the stern which is generally parallel to bristles 22, and preferably on the same side of stem 21 as the bristles. Thus, in the specific embodiment shown slot 25 is on the same side of stem 21 as bristles 22, as best seen in FIG. 4.
To further resist lever action, it is advantageous to make the longitudinal extent of slot 25 less than the longitudinal extent of socket 24, as shown. Thus, when the attachment is in mating position, the extreme end of the motor unit shaft will be encircled by the Walls of the socket, and there will be less tendency to spread the slot walls. Further, by positioning the pin-engaging recesses 27, 27' near the open end 26 of the slot, the walls of the remainder of the slot may be made sufiiciently thick to provide a relatively strong socket, while at the same time providing sufficient resiliency to permit the attachment to be pushed onto the shaft.
It will be seen that attachment of stem 21 to the motor unit is very simple and convenient. With the parts oriented as shown in FIG. 2, the stem is axially pressed onto the shaft end 12. When slot opening 26 reaches pin 14, the pin pushes aside the lips of the slot and seats in recesses 27, 27'. To separate, the stem is pulled axially away from the motor unit. Despite the relative ease of axial attachment and separation, the coupling effectively transmits rotational oscillation and resists the lever action resulting from. pressing the bristles against the teeth in cleaning.
FIG. 5 shows a modification in which the coupling 23' is similar to coupling 23 of the preceding figures, but includes a counter-slot 28 opposite the main slot 25. Counterslot 28 provides somewhat greater flexibility in the sides of slot 25 at theopen end thereof to facilitate attachment and removal. The depth of slot 28 is less than the wall thickness so that adequate wall strength still remains.
The toothbrush attachment of FIG. 5 may be employed with the motor shaft end configuration shown in FIGS. 2 and 4.
counter-slot 28 when in mating engagement. This further assures positive rotational oscillation of the toothbrush attachment without wear of the coupling or tendeney to spread the walls of slot 25.
I claim: 7
1. A toothbrush attachment which comprises a stern having laterally-extending bristles at one end thereof and a coupling at the other end thereof, said coupling having a longitudinally-extending, socket of non-circular cross-section, a longitudinally-extending slot in the wall of said socket and open toward said other end of the stem the width of the slot being less than the width of the socket in the corresponding direction, opposed transversely-extending recesses in the sides of said slot near the open end thereof, and a longitudinally-extending counter-slot in the inner wall of said socket on the other side of the socket from said slot, the depth of the counterslot being less than the wall thickness and the width of the counter-slot being less than the width of the socket in the corresponding direction.
2. A toothbrush attachment for a motor unit having a rotationally oscillatory shaft end of rectangular crosssection with 'a transversely-extending pin in one of the If desired, however, the motor shaft end 12, may be provided with a pin or tongue 29 which fits in the wide sides thereof and spaced a substantial distance from the end thereof, which attachment comprises a stem of plastic material having laterally-extending bristles at one end thereof and a coupling at the other end thereof, said stem being enlarged at the coupling end thereof, a longitudinally-extending socket in said coupling end having a rectangular cross-section adapted to mate with the motor unit shaft end, the longer cross-sectional dimension of said socket extending generally perpendicular to said bristles, a longitudinally-extending slot in the wall of said socket on the same side of the stem as said bristles and open at the open end of the socket, the width of the slot being less than the widthof the, socket in the corresponding direction, and opposed transversely-extending recesses in the sides of said slot' near the open end thereof adapted to receive the transversely-extending pin on the motor unit shaft, said slot being dimensioned to yieldably secure the toothbrush attachment on the motor unit shaft when in mating position therewith and the.
longitudinal dimension of said slot being less than the longitudinal dimension of said socket, and a longitudinallyeXtending counter-slot in the inner wall of said socket on the other side of the socket from said slot, the depth of the counter-slot being less than the wall thickness and the width of the counter-slot being less than the width of the socket in the corresponding direction.
References Cited in the file of this patent UNITED STATES PATENTS 2,130,661 Zaelest Sept. 20, 1938 2,158,738 Baker et a1. May 16, 1939 2,206,726 Lasater July 2, 1940