US1947324A - Toothbrush - Google Patents

Description

Patented Feb. 13, 1934 UNITED STATES PATENT GFFICE 3 Claims.

This invention relates to tooth brushes, and is in part a continuation of my prior application Serial No. 548,348,4iiled July 2, 1931.

The object of the invention is to produce a satisfactory motor driven rotary tooth brush of the type in which the brush is driven by a spring motor housed in the handle or grip portion of the device. Mechanisms lof this general type have been proposed heretofore, but have not gone into general use. The probable reasonis the diiiculty of housing in a compact casing a spring motor which will run long enough and develop adequate power. Other defects of prior art devices arose from the facts that themounting and location of the brush werenot conducive to convenient manipulation, and that the location of the control device was not such as to permit instant control of rotation while the brush was in use.

The present invention involves the coordination and arrangement of a number of features, some of which individually considered are old, to produce a device which is simple, compact, and convenient, and which in practical use has demonstrated advantageous characteristics.

'Ihe best embodiment of the invention so far developed is illustrated in the accompanying drawing, in whichz- Fig. 1 is a perspective view of the complete device;

Fig. 2 is a longitudinal axial section therethrough;

Fig. 3 is a view of the device showing how it is grasped in the hand of the user;

Fig. 4 is a fragmentary section, showing the detent which controls the starting and stopping of the spring motor:

Fig. 5 is an elevation showing the tubular stem unscrewed from the motor housing and the rotary brush unscrewed from the driving gear; and

Fig. 6 is a fragmentary longitudinal axial section of the end of the stem of the device, showing an alternate structure for the brush.

The spring motor is a self-sustaining unit comprising a self-sustaining frame, a heavy coil spring, a. speed multiplying gear train, and suitable controls. The frame includes a iiat plate 7 and a second plate formed with two parallel portions 8 and 9 connected by an offset 11` The two plates are rigidly connected together by a pair of pillars or studs riveted thereto, one of which appears at 12 and by a filler piece 13 which forms the end member of the frame and which, as will be described, oers means for attaching a removable brush carrier.

The purpose of the onset 11 is two-fold. It affords a space for the driving spring 14 and the portion 9 offers support for the arbors of certain of the gears. The spring 14 is a heavy coil spring attached to the offset 11 by a screw 15. Itsother 00 end is fast to an arbor 16 which is journaled in the plate 7 and in the portion 9 oi.' the secondplate. The arbor 16 carries, fast upon it, a winding gear 17.

Swiveled on the arbor 16 between the gear 17 and the portion 9 `of the' second plate is the main driving gear v18. The arbor 16' has a. one-way driving connection with gear 18 through -a conventional pawl and ratchet 'indicated at 19. The

purpose of this is to allow the brush mechanism l0 to remain at rest while the spring 14 is being wound.

The winding gear 17 is turned by a pinion 21 which is journaled at 22 in the plate 7 and which carries threaded to its outer end the hub 23 of a 75 pivoted winding key 24. The washers 25 are used to ll the space under the key and thus hold one face of the gear 21 closely against the plate 7. It thus becomes practicable to supportthe gear 2l on a single journal 22. Other arrangements may be substituted if preferred.

The mam driving gear 18 meshes with a small pinion 26 which, together with a larger gear 27, is fast on the arbor 28, the arbor being journaled in the plate 'I and the portion 9 of the 85 second plate. The gear 27 in turn meshes with a. small pinion 29 which, together with the gear 31, fast thereto, is rotatably supported in the plate 7 and the portion 8 of the second plate.

An escapement anchor 32 is journaled concen- 90 trically with the gears 29 and 31 (that is, it ls mounted to oscillate on the arbor which supports these two gears), and coacts with the escapement wheel 33 which is fast toa pinion 34 with which thegear 31 meshes. The escapement 96 wheel 33 and the pinion 34 are fast on an arbor 35 which is journaled in the plate 7 and the portion 8 of the second plate. The arbor 35 also carries fast upon it a combined bevel gear and detent.wheel. This wheel carries a series of beveled teeth 36 which merge into spur teeth 37 on its periphery.

There is a resilient blade or leaf spring 38 which is rigidly mounted on the frame member 13 and which has a tooth 39 adapted to engage the 106 plish this, a push button 4l is provided. 'I'he 110 position o! this push button is an important i'eature of the present invention, and will be described hereinafter.

The mechanism Just described involves essentially a motor spring, some means for winding the spring, a speed multiplying gear train driven by the spring, a speed limiting escapement applied near the end of the train where the angular speed is high and the force developed is relatively small, and an arresting detent preferably located similarly to the speed controlling escapement.

These elements are well known, but are here specially located and arranged.

The plates '1 and 8 are given such form that, together with the spring 14 and the main driving gear 18. they may be compactly housed in a relatively thin flat case which is approximately semicircular at its rear end and tapers toward its forward end adjacent the frame member 13. Progressive reduction in the'sizes of the gears and the careful location of centers produces a motor which can be housed in a case which comfortably ts even a small hand.

The case is preferably molded of a plastic material of good mechanical strength. This case consists of two parts 42 and 43 which make a tight joint by means of an overlapping flange 44. The two parts are cemented together to form a rigid, durable and moisture-excluding housing which closely embraces the motor frame. Thus, the motor mechanism may be packed with suflicient heavy lubricant for the life of the device.

The end frame member 13 is provided with a threaded aperture 45 to receive the threaded end of a tubular extension or stem 46 which carries the rotary brush. This stem is provided with an undercut flange 47 which overhangs an annular boss or rib 50 (see Fig. 2) formed on the case members 42 and 43. The boss 50 surrounds the aperture through which the threaded end of the member 46 is inserted and screwed into the threaded aperture 45 in the member 13.

Journaled in bearing bushings 60 in the tubular extension 46 is a shaft 48 which carries at its rear or inner end a bevel pinion 49 which meshes with the teeth 36. The shaft 48 carries at its outer end a small pinion 51 which preferably is of the spur type as shown, and which engages with teeth on the crown gear 52. The pinion and crown gear are the approximate equivalent of bevel gears. The pinion 51 is completely shrouded by a flange on extension 46. The crown gear 52 is mounted in a cup-like socket 53 formed at the end of member 46 and offset laterally relatively thereto. In the socket 53 is fixed a stud 54 serving as a pivot on which the hub of crown gear 52 is rotatably mounted. The crown gear 52 turns on the stud 54 and is overhung by the pinion 5l.

The hub of crown gear 52 is externally threaded, as indicated at 55, to receive the socketed back or body 56 of a circular brush. The bristles of such brush are shown at 57 and may take various forms. In fact, it is contemplated that various different types of brush will be sold, and may be used for different purposes, accordng to the preferences of the user.

Figs. 1, 2 and 5 show the bristles mounted in tufts in two concentric circles on a back of bone or composition. In Figs. 1 and 2, the tufts are so dimensioned as to produce a brush having a convex end, while in Fig. 5 the end of the brush is concave.

In Fig. 6 is illustrated a form of brush which approximates that used by dentists and which has certain highly desirable characteristics. The

base 56 of the brush is formed of sheet metal and receives an annular series of bristles 57 which are clamped against the base 56 by a cup 58. The cup 58 is held to the base 56 by a central eyelet or rivet portion 59 which may be, and preferably is, integral with the base 56. The bristles in this brush take the form of a more or less flaring conical annulus, depending on the contour oi the base 56e. The brush may be made by machinery and consequently is relatively inexpensive to produce.

The conical brush shown in Fig. 6 tends to enter between the teeth and may be used to secure an upward or downward brushing stroke by suitably positioning the device as a whole. Brushes of the type shown in Fig. 6 can be made interchangeable vvith brushes shown in the other iigures, if the threads be similarly dimensoned. Because of the relatively thin metal used in the base 56, it is, however, possible to use a more compact or smaller gear structure than is considered feasible where other bases are used, and advantages may be taken of this fact to reduce the size of the end of the device, if desired.

It will be observed that the gear 52 is shrouded in the cup 53, that the pinion 5l which overhangs the gear 52 is also shrouded, and that the upper t face of the base 56 or 56a is within the limits of extension 46 and the shroud which overhangs the pinion 51. It follows that the end of the device is quite compact so that it becomes possible to use bristles of good length.

The extension member 46 may readily be unscrewed from the member 13. An important asspect of the invention resides in the fact that a single motor device may, therefore, be used with a plurality of interchangeable brush supports 46. Thus a single motor may be used to drive mounts and brushes individual to different members of a household. The threads at the end of the brush support 46 and the flange 47 are so located that when the stem 46 is screwed tightly home, the axis about which the brush rotates will be substantially normal to the planes of the broad flat surfaces of the case members 42 and 43. Pref- 120 erably the bristles of the brush should project toward that flat face upon which the winding key 24 is mounted. Another important point is that the button 41 is on one of the narrow converging edges of the case and adjacent the junction of the case and the extension 46.

The device is intended to be held as indicated in Fig. 3; that is, it is grasped between the thumb which extends along one converging edge and the fingers which engage the other converging edge. A fiat side of the case is near to or against the palm of the hand, and the bristles of the brush project in a direction away from the palm of the hand. With the device constructed as described and held as just mentioned, the winding key is away from the palm of the hand. Il the device is held in the right hand, the control button is under the end of the thumb, and if it is held in the left hand, it is under the tip of the index ringer. In either case, it is positioned for ready manipulation without relaxing the grasp on the device.

The implement ts the hand comfortably, and when held as described can be used to reach all y portions of the users teeth without shifting the grip. To secure this effect, it is of importance that the member 46 extends in general prolongation of the tapered case; that the tapered case is formed with at least one flattened portion which assists in positioning the case in the users hand;

and that the brush is mounted on an axis which is approximately normal to the plane of the flattened portion of the case. The location of the control button on the narrow edge of the case, near the junction of the case and the brush-carrying extension, is favorable to precise manipulation, no matter which hand is used.

Full mobility of the wrist is essential if the brush is to reach all parts of the teeth. and can be secured only if the hand is in a natural and relaxed position. Severe limitation of the size of the ease and the adoption of a flattened tapered form for the case have resulted in a hand grip which is naturally grasped correctly and lightly by the user. 'I'he described location of the control button ensures that its manipulation will introduce no disturbing factor.

'I'he location of the motor spring and gear trains has been the subject of careful study, to keep size and form within desired limits, and yet secure a motor which will deliver ample power and speed for approximately three minutes on a single winding.

The design of the offset cup or socket 53 involves careful' correlation of the amount of oiset, depth of cup and height of brush to keep the size of the parts, and particularly the metal parts,

to a minimum, while properly masking the crown gear.l Much space is saved by so forming the base 56 of the brush that when screwed on the hub the base enters the annular space or channel between the hub and the teeth of the crown gear. In .this way, the outer face of the brush base 56 can be kept well below the side of extension 46 and near the axis of shaft 48 as best shown in Fig. 2.

While the arrangement described is preferred, the detailed description given above is intended to be illustrative and not limiting. The scope of the invention is defined by the claims, and modifications within the scope of the claims are contemplated.

What is claimed is:-

1. In a motor driven tooth brush the combination of a motor having a self-sustaining frame structure; a` divided casing enclosing said frame structure and having overlapping portions; a tubular extension passing through the junction of the parts of said casing, and in threaded engagement with said frame structure; a ange on said -extension overhanging and serving to clamp the portions of the casing against said frame structure; a rotary brush carried by said extension; andj driving connections between said motor and brush and housed in said extension.

2. In a tooth brush the combination of a hand grip; a tubular extension carried by said hand grip; a circular cup-like socket mounted at the end of said extension, with its bottom in a plane substantially parallel with the axis of said extension and its concave side toward said axis;

a pivot in said socket; a gear having a. hub rotatable on said pvot, and having an annular channel between said hubl and the teeth of the gear; a drive shaft rotatable in said extension; a pinion on said shaft housed in said extension and meshing with said gear; and a brush having a base removably mounted on the hub of said gear, and seated in said annular channel.

3. The combination of claim 2, further characterized in that the base of said brush projects from said circular socket and terminates a substantial distance below the opposite side of said tubular extension.

ALFONSO F. ZERBEE.

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