Rotary toothbrush

Dec. 31, 1963 a. f. zerbee 3,115,652

ROTARY TOOTHBRUSH Filed Sept. 27, 1962

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United States Patent Office _Pa!ented

3,115,652

ROTARY TOOTHBRUSH

Alfonso F. Zerbee, 5914 Coral Sea Ave., Rockville, Md. Filed Sept. 27,1962, Ser. No. 226,598

Claims. (Cl. 15—28)

This invention is concerned with power driven toothbrushes. More particularly the invention is concerned with motor driven toothbrushes and improvements therein.

It is known in the art to provide a rotary toothbrush and to drive the cleaning head by a suitable gear train and power means. An example of such devices, particularly spring motor driven devices, is clearly set forth in U.S. Patent 1,947,324, issued February 13, 1934 to Alfonso F. Zerbee, and the present invention, by the same inventor, represents an improvement over the structure disclosed therein.

In aforesaid Patent No. 1,947,324 there is disclosed a casing structure and an extension thereof, the former forming the main body portion of the toothbrush and defining a housing for a spring motor assembly, the latter terminating in a socket or bowl-shaped head defining a support for the rotary brushing implement. The spring motor, aside from embracing the usual winding mechanism including a winding key, also includes a gear train and speed governing means to control the brush and motor speed. The structure disclosed therein also includes a shaft carried within the extension portion, driven by the motor and driving, via a right angular gear arrangement, the brush implement, which, in turn, is rotatably mounted within the socket or bowl-shaped terminal end of the extension.

While the brush structure shown in Patent No. 1,947,324 and the present invention share many common advantages, the former structure also is possessed of certain disadvantages which are overcome by the improved structure hereof.

Among the common advantages shared by the two· structures are complete freedom of use without the necessity of external connections to any power source; freedom from the possibility of electric shock, always a factor of concern where electrically powered implements are used in wet surroundings and, finally; freedom from extensive maintenance since there are very few parts in a spring motor which may require repair, except possibly the drive spring itself.

The disadvantages of applicant’s prior structure and also, broadly, of the prior art, irrespective of the type of drive mechanism employed, which are overcome by the present invention are numerous. Initially, the drive motors of the prior art devices are often noisy, while the present invention is considerably more quiet in operation. Secondly, difficulty was and is often experienced with the prior art devices in changing the brushing implement, per se, as, for example, where a single power source is used by the various members of a family, each member having his or her own individual cleaning brush. Additionally, the provision for rewinding the spring motor, if such is used, of the prior art devices are cumbersome and detract from the use and appearance of the implement. Further, it has been found that more complete cleansing action is obtained, if rather than rotating about a fixed axis as exemplified in said Patent No. 1,947,324, the brushing element not only rotates, but also, may be tilted or wobble about its axis of rotation.

Accordingly, an object of the present invention is to produce a driven rotary dental tool which is convenient to use, and productive of better cleaning action than heretofore obtained.

A further object of the invention is to produce an economical, easily used rotary toothbrush wherein the cleaning implement is provided with a unique, universal tilting action which improves its cleaning function.

Still another object of the invention is to produce a rotary driven toothbrush which is readily manipulated and easy to clean.

A still further object of the invention is to produce a rotary toothbrush wherein multiple brushes may be readily used interchangeably with a single power source.

These and other objects of the invention, not specifically referred to but inherent therein, are accomplished by providing a main housing or case, a prime mover therein, preferably a spring motor including a releasable winding handle, a motor speed control mechanism comprising a centrifugal brake having spring biased centrifugally extended brake shoes engageable with a non-rotatable or fixed friction resistant portion of a further housing, a tubular extension housing carried by said further housing, said extension terminating in a bowl-shaped socket, a pivot in said socket, brush supporting gear means on said pivot and a brush removable mounted on said gear means, a shaft and gear drive means for the brush supported within the said extension and releasable means for retaining the brush supporting gear means and the brush loosely in position on said pivot for rotary and tilting or wobbling motion thereon while permitting removal of same when desired. Port means are also provided in the extension and socket to facilitate cleaning thereof.

In describing the invention in detail, reference will be made to the drawings attached hereto and forming a part of the disclosure, v/herein

FIG. 1 is a view of the device as held in the hand of a user,

FIG. 2 is an elevational sectional view taken through the approximate longitudinal center of the forward portion only of the device shown in FIG. 1,

FIG. 3 is a sectional view taken along the line 3—3 of FIG. 2, and showing the centrifugal, speed regulating brake in an inactive or inoperative condition,

FIG. 4 is a view similar to FIG. 3 but showing the cetrifugal, speed regulating brake in operating condition,

FIG. 5 is a side elevation of the head and brush showing the brush release means in normal brush holding position and, in dotted lines showing the same in releasing position,

FIG. 6 is a perspective view of the back of the brush holding head showing the releasable holding means, and

FIG. 7 is a perspective view of a desirable motor energizing handle.

Turning initially to FIG. 1, it may be seen that the invention includes a main body or case portion 1®, an intermediate governor assembly 2® and an extension portion 39. The case 1® is formed of sheet metal, molded plastic or other suitable material, and is preferably formed in two parts having a central parting line similar to that shown in Patent No. 1,947,324. The case 10 is hollow and defines a housing for a spring motor 1 which may be of the type shown in the aforesaid patent. The motor 1 includes a coiled spring, the usual ratchet type of winding mechanism and a suitable gear train wherein the spring energy is converted into rotary motion.

Suitably associated with the case or housing 10 so as to be in convenient reach of the user’s thumb, when the device is held in its usual utility position, is a start-stop lever 2. Lever 2 extends through a slot provided in the housing and is resiliently mounted so as to be movable relative to the housing 10 and one member of the gear train of the motor 1 so that movement thereof will cause a suitable abutment to engage or release the gear train to start and stop the motor. This start-stop mechanism is convenional and amply illustrated in said prior Patent No. 1,947,324.

It v/ill be seen from an inspection of FIG. 7 along with

3,115,652

FIG. 1, that one half of the housing 10 is provided with an aperture, not shown, through which projects a shaft 3, which shaft is in turn connected, by conventional ratchet winding means, to the spring motor 1. The shaft 3' is generally centrally located with respect to the housing’s sides and has a pulley shaped spool 5 fixed to its exposed end. The spool 5 includes a depressed central annular groove 6 and enlarged annular flanges 7, 7'. The central groove 6 is diametrically intersected by a pair of coaxial bores 9 and 11 which extend inwardly from the bottom of groove 6 toward the center of the spool 5. The bores 9 and 11 lie in a common plane bisecting the spool 5 midway between the annular flanges 7, 7'.

In slidable engagement with the spool 5 is a crank arm 13. At one end, the crank arm 13 carries a swingable handle 15 connected thereto by a conventional slot and pin connection 14 such that the handle may be moved through an approximately 180° arc in either of two directions and in a single plane bisecting the longitudinal axis of the handle. At its opposite end the crank arm 13 is enlarged somewhat and bifurcated to provide two spaced, parallel fingers 16, 16' which are joined together at their terminal ends by an arcuate bight 17. Centrally located on the bight portion 17 of the crank arm 13 and projecting diametrically inwardly toward the open area defined between fingers 16, 16', is a pin 18, which pin is of a diameter complementary to that of the bores 9 and 11 in spool 5. It will be apparent that fingers 16, 16' are so spaced as to rest in the annular grooved portion 6 of spool 5 and that, because of the generally oval shape of this bifurcated end of crank arm 13 it is bodily movable, along its longitudinal axis, with respect to spool 5. Thus, if the handle 9 is moved in one direction, the bight 17 approaches spool 5 and pin 18 may, by slight rotation of crank arm 13 via handle 15, be caused to drop into one of the bores 9 or 11 and continued rotation of the crank arm 13 will enable the spring motor 1 to be wound. After winding, movement of the crank arm 13 in the opposite direction, longitudinally of its length, will free pin 18 from either bore 9 or 11 and arm 13 may be moved to the position shown in FIG. 1, i.e., generally parallel to the longitudinal axis of the housing 10, whereupon swingable handle 15 is swung through a 180° arc and snapped into locking engagement with a typical resilient clamp 19.

The above described arrangement serves two functions, first, the handle is locked in an out of the way position as clearly shown in FIG. 1, and second, if the motor 1 is of the type wherein the winding shaft rotates during its operation, the shaft 3 will be free to rotate without interference from the crank arm 13 or without the necessity of having the crank rotate.

Referring further to the drawing, and in particular to FIG. 2, it will be seen that the governing assembly 20 comprises a fixed, annular, cup-shaped housing 21, having a central threaded aperture 22 in the bottom thereof. Disposed within the housing 21 and facing in the opposite direction thereto is a further cup-shaped member 23 comprising a brake drum. This drum 23 is provided at its bottom with a cylindrical sleeve 24 formed integrally therewith and having a threaded exterior 25 which, in turn, forms the connection with motor housing 10, being screwed into a suitably threaded aperture 12 provided therein. The brake drum 23 is fixedly connected to housing 21 by any suitable means. For purposes of simplicity this connection means is illustrated as a set screw S threaded through the housing 21 and abutting against the exterior face of brake drum 23.

The cylindrical sleeve 24 is provided further with a bushing 26, this bushing supporting shaft 27 which extends from within motor housing 10 through the governor section 20 and through extension 3® terminating at the extreme end of the latter as will be more fully described hereafter. At its opposite ends shaft 27 has fixed thereto, by any suitable means, pinion gears 28 and 31, respectively, such that motor 1 may drive the brushing implement.

Suitably mounted upon and fixed to the shaft 27 for rotation therewith is a pair of diametrically opposed, outwardly extending pins 28, 28'. Slidably mounted on the pins are a pair of segmentally shaped weights 29, 29', having arcuate outer surfaces adapted to engage the inner cylindrical surface of drum 23. These weights are also provided with central recessed areas 33, 33', respectively, into which the pins 28, 28' project. Bearing against each weight 29, 29', respectively, and the ends of the pins 28, 28', respectively, are small coil springs 32, 32'. The springs are biased in compression and are fixed in place surrounding the pins by providing the pins with enlarged heads or by threading nuts and washers on the ends such that the diameter of the ends of the pins exceeds that of these springs 32, 32'.

It may be seen, then, that, as long as the shaft 27 is stationary, the weights 29, 29' are biased inwardly toward the center of rotation of the shaft 27 by the springs and they do not contact the inner wall of drum 23. However, as soon as shaft 27 is rotated, the centrifugal force acting on the weights 29, 29' v/ill cause them to move outwardly against the compression forces exerted by springs 32, 32' and the arcuate peripheries thereof will contact the inner v/all of brake drum 23 to act as a friction brake slowing down the rotative speed of shaft 27. By a proper selection of the friction area between the weights 29, 29' and the drum 23 and as well, selection of springs having the proper compression forces, the speed of the motor 1 can be regulated to very close limits. Thus the energy of spring motor 1 is not expended in a single uncontrolled burst of rotation, but rather the energy is expended in a controlled fashion at relatively constant speed over a reasonably long period of time.

As has been set forth, the bottom of the governor housing 21 is provided with threaded aperture 22. Threaded into this aperture, as shown clearly in FIG. 2, is an extension housing and brush supporting assembly 30. Obviously this assembly, like housing 21, is coaxially and concentrically disposed along the longitudinal centerline of the case 10, such that shaft 27 may extend from motor 1 through the device to the cleansing implement.

The extension housing 30 is comprised of a slender, tubular central portion 33 terminating in enlarged ends 35 and 37. End 35 forms a cylindrically shaped base adapted to abut against the bottom of the governor housing 21 and being affixed thereto by means of a threaded sleeve 39 which threadedly engages aperture 22 and v/hich is internally bored or hollowed out to receive a bushing member 41. This bushing supports shaft 27 approximately midway between its terminal ends.

The opposite end 37 of the extension 30 is in the form of a shallow bowl or socket having its center disposed in an axis normal to the longitudinal axis of shaft 27 and its bottom portion offset but parallel to the latter axis. This bottom portion is provided with a central upstanding spindle 43 which may be formed integrally therewith, the purpose of which will be apparent hereinafter.

As has been stated, shaft 27 terminates adjacent the socket end of extension 30 and is provided with spur gear 31. As seen in FIG. 2, this gear 31 rotates in a plane generally perpendicular to the bottom of the socket 37 and is so disposed with respect thereto that it will mesh with the teeth 49' of crown gear 45 resting on spindle 43 and having a peripheral size closely approximating that of the socket 37. The end of the shaft 27 is supported further in a bushing or bearing 47 suitably fitted into the tubular portion 33 of the extension 30. Thus this end of shaft 27, which is somewhat reduced in diameter, as compared to the opposite end carrying pinion 28, is firmly supported to assure that the pinion 31 will not whip as the shaft rotates.

Crown gear 45 includes a central thickened area which defines a hub 48. The external cylindrical surface 46 of the hub 48 which is concentric with the peripheral gear teeth 49 is threaded to receive the bored and threaded base

3,115,652 of the cleaning implement 5® which includes bristles 52 embedded therein.

The opposite side of the hub 48 is provided with a cylindrical recess or bore 53 which receives spindle 43 about which the implement 5® rotates.

Upon careful inspection of FIG. 2 it will be noted that the height of spindle 43 exceeds the depth of the recess 53 such that 'the base of the crown gear 45 is spaced above the bottom of the socket 37. Also the diameter of the bore 53 is greater than the diameter of spindle 43. Thus the crown gear 45 and implement 59 may tilt or wobble on the spindle 43. However, due to the fact that the peripheral teeth 49 of the gear must mesh with pinion 31, the degree of wobble or tilting is limited to the extent necessary to prevent disengagement of these parts. At the same time, enough freedom of motion is provided so that the crown gear and the implement may be tilted as a unit to enable its removal from within the bowl shaped socket as the bore 53 is lifted from spindle 43 and gear teeth 49 are disengaged from pinion 31.

In order to restrain the crown gear 45 on the spindle 43 and in contact with pinion 31 at all times, the tubular part 33 of extension 3® receives a split collar 55 which grips the exterior thereof tightly, but yet is slidable therealong. The split collar 55 is formed integrally with and supports a narrow connector arm 56 which extends toward the socket portion of the extension 30 and overlies the bottom thereof terminating in a plurality of prongs or fingers 57 which curve around the sides of the socket and have their ends slightly overlying the open peripheral edges of the socket. The ends of the prongs 57 because of the space defined between them prevent the crown gear 45 from falling out of the socket 37 so long as said prongs overlie the open space defined by the socket. At the same time, said prongs prevent the crown gear 45, and hence the cleaning implement 5®, from falling out of the socket, they also permit these elements a certain degree of looseness on spindle 43 so that the desired tilting or wobbling of the crown gear thereon is achieved.

If, however, the split collar 55 is moved on the extension 3® toward the socket 37, it will be seen that the prongs 57 are moved so as to no longer overlie the socket and the cleaning implement 50, along with crown gear 45, may be easily removed and another substituted in its place. It is quite simple, then, to use one power unit as a means of driving individually a selected one of a multiplicity of individual brushes. Further, since the base 51 of the brush 50 is threadedly engaged with hub 46 of crown gear 45, it is quite easy to replace worn out brushes without replacing the crown gear 45.

To facilitate cleaning of the device after each use the socket 37 and extension 30 are provided with apertures 60 as shown in FIGS. 2 and 6 whereby the cleaning fluid, usually water, may completely enter the socket and the interior of the tubular portion of the extension to cleanse these parts and subsequently be drained therefrom. The bushing 41 may, if necessary, include a sealing means such as an O ring to prevent the cleansing fluid from entering the governor housing 20.