US3802420A

US3802420A - Portable oral hygiene device

Info

Publication number: US3802420A
Application number: US00266295A
Authority: US
Inventors: G Moffat; J Carlucci
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-06-26
Filing date: 1972-06-26
Publication date: 1974-04-09
Anticipated expiration: 1991-04-09

Abstract

A portable oral hygiene device having a housing member with a forward portion removably mounting a rotary workhead such as a toothbrush on an axis extending laterally from the housing member, and with a rearward portion mounting a rotary drive shaft therein. Various combinations of an endless belt, pulleys, gears and/or rods are provided inside the forward portion of the housing member in different embodiments to couple the rotary workhead with the rotary drive shaft. In some embodiments the forward portion of the housing member is detachable from the rearward portion.

Description

United States Patent 1 Moffat et a1.

Apr. 9, 1974 PORTABLE ORAL HYGIENE DEVICE Inventors: Gordon H. Moffat, 4927 El Sereno;

. Jessel Carlucci, Jr., 3110 Brookhill St., both of La Crescenta, Calif. 91214 Filed: June 26, 1972 Appl. No.: 266,295

US. Cl 128/56, 15/28, 128/62 A Int. Cl A6lh 7/00 Field of Search 128/56, 62 A; 32/59;

References Cited UNITED STATES PATENTS 3/1966 Cantor 15/28 11/1965 Dayton et a1. 15/28 10/1957 Gregoire t 15/28 Sharps [5/28 Primary ExaminerLawrence W. Trapp Attorney, Agent, or FirmHarris, Kern, Wallen &

Tinsley 5 7] ABSTRACT A portable oral hygiene device having a housing member with a forward portion removably mounting a rotary workhead such as a toothbrush on an axis extending laterally from the housing member, and with a rearward portion mounting a rotary drive shaft therein. Various combinations of an endless belt, pulleys, gears and/or rods are provided inside the forward portion of the housing member in different embodiments to couple the rotary workhead with the rotary drive shaft. In some embodiments the forward portion of the housing member is detachable from the rearward portion.

16 Claims, 17 Drawing Figures PATENTEDAPR 9 I974 SHEU 2 BF 3 lllll PATENTEBAPR 9 ISM 3,802,420

sum 3 or 3 PORTABLE ORAL HYGIENE DEVICE This invention relates generally to oral hygiene devices and more particularly to a portable electric oral hygiene device having a rotary workhead such as a toothbrush laterally mounted on a forward end of a handle member.

Prior art electric oral hygiene devices designed for home use have usually employed an oscillating workhead which moves back and forth or up and down. In contrast, practicing dentists continue to use rotary workheads to perform the various prophylactic-and therapeutic drilling and cleaning activities in connection with their sophisticated electrical equipment.

Accordingly, it is a primary purpose of this invention to provide a portable electric hygiene device having a rotary workhead, thereby obtaining the advantages of the permanent rotary apparatus used in a dentist's offree without sacrificing the small size and weight which has made the oscillating .home toothbrushes so popular and useful. A related object is to provide a low speed portable rotary oral hygiene device operating at 2,000 rpms or less which is suitable for either cleaning or massaging activities.

It is'another object of the invention to provide a portable electric rotary hygiene device which is capable of removably mounting additional rotary work heads such as cleaning cups, stimulators, or pointed brushes in place of conventional toothbrushes.

An additional object of the invention is to provide a device having the aforementioned characteristics which encloses all of the operative moving parts except the rotating workhead inside of a small, easily gripped elongaged housing member. A related object is to provide a small diameter waterproof casing on a forward end of the housing, with a rotary workhead extending laterally from the casing, to facilitate easily observable and controllable manipulation of the workhead inside a person s mouth which contacts tooth and gingival surfaces for cleaning and therapy.

Still another object of the invention is to provide a rearward housing section, carrying an electric drive motor, which is detachable from a forward portion of the housing, in order to enable each member of a group such as a family to have their own custom-sized forward portion and workheads without the expense and inconvenience of individual drive units, and to enable one person to have a plurality of differently designed forward portions capable of being used with a single drive unit.

Yet another object of the invention is to provide a control switch only on a detachable forward portion of the device so that the drive motor cannot be actuated unless a handle unit is actually in operative attached position.

A further object of the invention is to provide a device having the aforementioned characteristics wherein a drive shaft is mounted for rotation on an axis substantially parallel to a longitudinal axis of the housing member and is coupled inside the housing member to a rotary workhead mounted for rotation on an axis substantially perpendicular to the longitudinal axis of the housing member. A related object is to provide an alternative embodiment wherein the drive shaft axis is sub- A more specific object of the invention is to provide a portable oralhygiene device having the aforementioned characteristics which includes a drive rod or endless belt extending inside the housing coupling the rotary drive shaft with the rotary workhead, and which incorporates pulleys, gears, or the like in the front or back of the forwardportion of the housing to convert rotary energy about an axis of rotation of the drive shaft into rotary energy about a nonaligned axis of rotation of the workhead.

An additional object is to provide a portable oral hygiene device which has optimum size, shape, and weight for easy manual manipulation by children as well as adults, and which is nevertheless inexpensive, easy to manufacture and repair, and which will provide reliable, safe, trouble-free performance under diverse conditions, during home use and while traveling.

The foregoing objects, advantages, features, and results of the present invention, together with various other objects, advantages, features, and results which will be evident to those skilled in the art in the light of this disclosure, may be achieved with the exemplary embodiments of the invention illustrated in the accompanying drawings and described in detail hereinafter.

DESCRIPTION OF DRAWINGS In the drawings:

FIG. 1 is a perspective view of a first embodiment of a portable oral hygiene device;

FIG. 2 is a different perspective view of the embodiment of FIG. 1 showing a rearward portion of a housing member detached from its forward portion;

FIG. 3 is a detailed exploded view of the forward housing portion of the embodiment of FIGS. 1 and 2 showing an endless drive belt coupling a drive shaft to a relatively perpendicular workhead, with directional pulleys adjacent the drive shaft;

FIG. 4'shows one alternate form of a rotary workhead;

FIG. 5' shows another alternate form of a rotary workhead;

FIG. 6 shows still another alternate form of a rotary workhead;

FIG. 7 is a side view showing one form of a removably mounted workhead;

FIG. 8 is a displaced side view of FIG. 7;

FIG. 9 is a side view showing another form of a removably mounted workhead;

FIG. 10 shows a top view of FIG. 9;

FIG. 11 shows a side view of still another form of a removably mounted workhead;

FIG. 12 is a detailed exploded view of an alternate structure to FIG. 3 showing a drive rod coupling a drive shaft to a relatively perpendicular workhead, with directional gears adjacent the workhead;

FIG. 13 is a partially exploded, partially cutaway perspective view of a second embodiment of a portable oral hygiene device showing an endless drive belt cou pling a drive shaft to a relatively parallel workhead;

FIG. 14 is a partially exploded, partially cutaway side view of a third embodiment of a portable oral hygiene device showing an endless drive belt coupling a drive shaft to a relatively perpendicular workhead, with directional gears adjacent the drive shaft;

FIG. 15 is an exploded perspective view of an alternate form of the embodiment of FIG. 14 showing a rearward portion of a housing member detachable from its forward portion;

FIG. 16 is a detailed exploded view of a portion of FIG. 15; and

FIG. 17 is a partially exploded, partially cutaway view of an alternate structure for FIGS. 3, 13, 14, or 16 showing an endless drive belt coupling a drive shaft to a relatively nonaligned workhead, with directional pulleys adjacent the workhead.

Generally speaking, the invention includes a composite body member such as an elongated housing having a longitudinal axis 11, a rearward portion 12 carrying a drive motor 14 coupled to a rotary drive shaft 15, and a forward portion 16 with a tapered front end 18 carrying a removable laterally extending rotary workhead such as a rotary toothbrush 20. In two of the illustrated embodiments, the rotary workhead 20 is coupled with the rotary drive shaft through an endless belt 22, while in another embodiment a drive rod 24 is substituted for the endless belt. In each instance, the various moving structural elements are designed to fit inside the housing 10in a minimum of space, thus providing an outer housing surface shaped and sized as a compact handle extending the full length of both the rearward and

forward portions

12, 16 and tapering to a small diameter at the front end 18. In addition, the embodiments of FIGS. 15-16 and FIGS. 2-3 provide an oral hygiene device wherein the forward portion 16 is detachable from the rearward portion 12, all as described in more detail hereinafter.

Referring to the embodiment of FIGS. 2 and 3, the rearward portion 12 of the housing 10 includes a front plate 26, a pair of studs 28 with enlarged heads 30, and a battery unit 32. The front plate 26 constitutes the forward boundary of the rearward portion 12, and the studs 28 extend forwardly beyond the front plate 26 and are symmetrically positioned relative to the rotary drive shaft 15 and a square head 34 thereon which also extends forwardly beyond the front plate 26. The forward portion 16 of the housing 10 includes a back plate 36, a pair of keyhole terminals 38, a control switch 40, a support bracket 42, and a short transfer rod 44 having a square center recess. The back plate 36 constitutes the rearward boundary of the forward portion 16 of the housing 10 and has an opening for receiving the rotary drive shaft 15. The keyhole terminals 38 are symmetrically positioned relative to the opening in the back plate 36. The control switch 40 includes a base 46 providing a support and seal against the'outer casing of the forward portion 16, and also includes lead wires 48 connecting the control switch with the keyhole terminals 38. The square recess of the short transfer rod 44 is located on its large diameter end which is seated inside the opening in the back plate 36, with its small diameter end passing through the support bracket 42 and a bracket bushing 50. Suitable fasteners such as screws are used to secure the back plate 36 to the support bracket 42, with insulation covers 52 preventing contact between the keyhole terminals 38 and the support bracket 42 acting as a seal.

The endless belt 22 is engaged by a front pulley 54, a back pulley 56, and a pair of directional pulleys 58. The structure for journaling the toothbrush and the front pulley 54 coaxially on the front end 18 of the forward portion 16 of the housing 10 includes a bushing 60, a seal bushing 62, an axle 64, and the casing of the front end 18. The front pulley 54 is positioned between the bushing 60 and the seal bushing 62 on the outside of the axle 64 where it is held by a frictional press-fit of the pulley on the axle. The seal bushing 62 is seated in a matching aperture in the casing of the front end 18 at a predetermined angle relative to the longitudinal axis 11 of the housing 10 and prevents oral moisture from passing into the inside of the housing. The toothbrush 20 or other rotary workhead is removable on one end of the axle 64 for rotation thereon. The back pulley 56 is attached to the short transfer rod 44 adjacent the support bracket 42, while an axle 66 rotatably mounted on side flanges 68 of the support bracket carries the pair of directional pulleys 58.

In the workhead shown in FIGS. 7 and 8, the toothbrush 20 is removably mounted inside the axle 64 by a compressible spring wire 69 which extends outwardly beyond a shank 70 of the toothbrush 20 for engagement in a matching slot (not shown) in the axle 64. Another form of workhead is shown in FIGS. 9 and 10 wherein a modified shank 70' has a flattened side 72 adapted to fit inside a matching axle 64, with split legs 74 on the top of shank 70' being compressible inwardly to fit a matching constriction (not shown) in the axle 64. FIG. 11 shows a different form of workhead incorporating a threaded shank 70" for engagement with matching threads (not shown) in axle 64, the threads being oriented to provide additional tightening upon rotation of the toothbrush 20.

By providing one of the foregoing alternate forms of structure for removably mounting workheads, it is possible to employ a variety of different rotary workheads with a single housing 10, such as, for example, the eccentrically mounted stimulator 74 shown in FIG. 4 which is used to stimulate the gingival tissues and thereby treat pyorrhea. An alternate form of rotary workhead is shown in FIG. 5 as a flexible rubber cleaning cup 76. Further alternate workheads such as the pointed cleaning brush 78 of FIG. 6 are particularly useful for cleaning difficult oral locations which are otherwise inaccessible, such as between teeth which are partially covered with orthodontic appliances. For example, rotary action of the brush 78 is especially helpful in cleaning the area between teeth exposed to decay by new plastic orthodontic brackets which do not completely surround each tooth.

In the operation of the portable oral hygiene device as described and shown in the foregoing illustrative embodiment, the desired workhead is chosen from

exemplary workheads

20, 74, 76, 78, or other workheads not shown and inserted into axle 64 to be in position for rotation about an axis 80 which is substantially perpendicular to the longitudinal axis 11 of the housing 10. The rearward portion 12 of the housing 10 is then removed from a battery charging unit, or alternatively is removed from its storage container and plugged into a volt AC outlet. The forward portion 16 and the rearward portion 12 of the housing 10 are then joined together by placing the front plate 26 adjacent the rear plate 36 so that the studs 28 pass through the keyhole terminals 38 while at the same time the square head 34 of the drive shaft 15 engages the matching recess in the short transfer rod 44. Relative manual rotation of the forward and

rearward portions

16 and 12 places the enlarged heads 30 of the studs 28 into locking position behind the narrow portion of the keyhole slots in the keyhole terminals 38 to provide a secure structural connection as well as providing an electrical connection from the control switch 40 in the forward portion 16 through the keyhole terminals 38 and the studs 28 to the drive motor 14 in the rearward portion 12 of the housing 10. Manual depression of the control switch 40 serves to actuate the drive motor 14 to rotate the rotary drive shaft 15, which rotary motion is imparted through the short transfer rod 44, the back pulley 56, the endless belt 22, the directional pulleys 58, and the front pulley 54 to turn the axle 64 and the rotary workhead mounted thereon. Thus, the foregoing structure provides a rotary contact surface 82, with all of the inherent benefits associated with sophisticated permanently installed rotary apparatus of a dentists office, in a compact self-operated easily manipulated oral hygiene unit, thereby constituting a substantial and significant improvement over the oscillating and/or agitating workheads of the prior art portable oral hygiene devices.

In describing variations of the aforementioned embodiment and additional embodiments of the invention hereinafter, the same numbers are used to identify and refer to parts which are substantially identical in description and function to previously numbered parts, while new identification numbers are used where the need arises to identify modified or new parts and elements shown in thedrawings.

FIG. 12 shows an alternate structure for the subject matter of FIG. 3 incorporating the drive rod 24 in place of the endless belt 22. More particularly, the forward portion 16 of the housing includes the back plate 36, the keyhole terminals 38, the bracket bushing 50, first and

second support brackets

84 and 86, a crown gear 88, a spur gear 90, and a transfer rod 92 having a square center recess. The transfer rod 92 constitutes the back end of the drive rod 24 and is sized to fit within the bracket bushing 50 with a stop ring 94 extending beyond the transfer rod 92 for positioning betweenthe first and

second support brackets

84 and 86. Suitable fasteners such as screws are used to secure the back plate to the two

support brackets

84 and 86. The crown gear 88 is positioned between the bushing 60 and the seal bushing 62 on the outside of the axle 64 where it is held by a frictional press-fit, all at the front end 18 of the forward portion 16 of the housing 10. The spur gear 90 is located on the forward end of the drive rod 24 for engagement with the crown gear 88. Although it iswithin the spirit of the invention to employ other gears and the like in place of the crown and spur

gears

88 and 90 in order to provide rotation of the workhead on an axis extending laterally from the drive rod 24 and/or the longitudinal axis 11 of the housing 10, the use of gears at such location adjacent the workhead 20 provides a heavier and bulkier end which may not be as suitable in some circumstances for easy manipulation, as by children, in comparison to the structure of FIG 3.

The embodiment of FIG. 13 provides a casing projection 96 extending laterally from the rearward portion 12 of the housing 10 for carrying the drive motor 14 coupled to a drive shaft 15' mounted substantially perpendicular to the longitudinal axis 11 and substantially parallel to the axis of rotation of the axle 64 and workhead carried thereon. A rear pulley 98 is mounted directlyon the drive shaft 15' for the endless belt 22. The outer surface of the housing 10 and the casing projection 96 define a handle having a shape which is more difficult to grasp and manipulate than the streamlined handle of the other embodiments of the present invention. However, utilization of the structure of the embodiment of FIG. 13 does enable the elimination of some gears, pulleys or the like which are otherwise necessary for changing the direction of rotary energy between the drive shaft 15 and the workhead 20.

The embodiment of FIG. 14 provides a unitary housing 10 wherein the drive shaft 15 in the rearward portion 12 includes a spur gear 98 on the forward end thereof. The forward portion 16 of the housing 10 includes a back pulley 100 and a crown gear 102 mounted on a common axle 104 which is substantially perpendicular to the drive shaft 15 and substantially parallel to the axle 64 carrying the rotary workhead 20. The spur gear 98 meshes with the crown gear 102 to drive the endless belt engaged by the front and back pulleys 54 and 100. A thin teflon washer 106 having an inside diameter slightly smaller than the outer diameter of the axle 64, is cemented, as by epoxy, to the outer edge of a bushing 62' allowing the teflon washer 106 to cone slightly outwardly when forced over axle 64 to provide a seal and prevent entry of moisture from the mouth.

FIGS. 15 and 16 show a modification of the structure of FIG. 14 in order to provide a rearward portion 12 which is detachable from the forward portion 16. In this regard, the axle 104 is replaced by a first rod 108 mounted in the rearward portion 112 carrying the crown gear 102 on its lower end between two bushings and having a square recess on its upper end 112. A second rod 1 14 also constitutes a partial replacement for axle 104 and is mounted in the forward portion 16 to carry the back pulley 100 between bushings 1 l6, and includes a square lower end 118 sized to fit within the square recess on the upper end 112 of the first rod 108. The rearward portion 12 also includes a control switch 40' on a base plate 46 and connected through wires .48 to the drive motor 14 and the battery 32. A top bracket 120 with hook arms 122 extending on opposite sides of a central aperture is mounted over the second rod 114 on the forward portion 16 of the housing 10. A matching bottom bracket 124 has first and second opposite offset

arms

126 and 128 which define slots for receiving the hook arms 122, and a central aperture allows mounting over the first rod 108 on the rearward portion 12 of the housing 10. The foregoing structure allows the rearward portion 12 to be connected to the forward portion 16 with the drive shaft 15 either perpendicular or parallel to the longitudinal axis 11 of the forward portion 16 of the housing 10. Also, by varying the relative positioning of the top and

bottom brackets

120, 124 and/or by adding more pairs of slots in bottom bracket 124 for receiving the hook arms 122, it is possible to provide a diverse choice of relative angular positions between the forward and rearward portions of the housing.

When it is desirable to provide workheads which are mounted on the front end 18 for rotation on an oblique axis relative to the longitudinal axis 11 of the housing 10, the structural variation of FIG. 17 can be utilized in the embodiments of FIGS. 2-3, FIG. 13, and FIGS. 14-16 without having to unduly enlarge the front end. In this regard, directional pulleys 130 are mounted adjacent the rotary workhead 20 to engage the endless belt 22 immediately before it engages the front pulley 54 mounted on the axle 64 carrying the rotary workhead 20. It will therefore be appreciated to those skilled in the art that the invention is not limited to workheads which rotate on an axis perpendicular to the longitudinal axis of the housing 10, but can be adapted to meet any angular requirements which may arise in connection with specialized oral hygiene workheads.

The invention illustrated in the drawing and description herein therefore provides a useful and unique portable hygiene device which encloses all of the operative parts within a compact, easily manipulated handle member while at the same time providing all of the advantages inherent in a removably mounted rotary workhead extending laterally from a tapered forward end of the handle member.

Although exemplary embodiments of the invention have been disclosed and discussed, it will be understood that other applications of the invention are possible and that the embodiments may be subjected to various changes, modifications, and substitutions without necessarily departing from the spirit of the invention.

We claim as our invention:

1. A portable oral hygiene device comprising in combination:

a housing member with a longitudinal axis, including handle means for manually grasping said housing member, and having a forward portion and a rearward portion, said rearward portion of said housing means including back casing means for carrying therein a drive motor coupled to said rotary drive shaft, and said forward portion of said housing means including small diameter front casing means for sealing said forward portion of said housing member from oral moisture;

a rotary drive shaft mounted in said rearward portion of said housing on an axis substantially parallel to said longitudinal axis of said housing member;

a rotary workhead;

journal means in said forward portion of said housing member for rotatably mounting said rotary workhead on said forward portion on an axis extending laterally relative to said longitudinal axis of said housing member; and

transfer means inside said housing member coupling said rotary drive shaft with said rotary workhead for driving said workhead from said shaft, including directional means for converting rotary energy about said axis of said rotary drive shaft into rotary energy about said axis of said rotary workhead.

2. The device of claim 1 wherein said transfer means includes an endless belt, and including directional means positioned in said forward portion of said housing member displaced from said front casing means.

3. The device of claim 2 wherein said transfer means includes first pulley means mounted in said forward portion of said housing member coaxial with and attached to said rotary drive shaft for engaging said endless belt, and said directional means includes second pulley means for engaging said endless belt.

4. The device of claim 2 wherein said transfer means includes pulley means mounted in said forward portion of said housing member adjacent said rotary drive shaft for engaging said endless belt, and said directional means includes gear means for coupling said pulley with said rotary drive shaft.

5. The device of claim 4 wherein said housing member includes means for removably attaching said forward and rearward portions of said housing member.

6. The device of claim 5 including means for removably attaching said forward and rearward portions of said housing member in more than one relative angular relationship.

7. The device of claim 1 including directional means positioned in said forward portion of said housing member in said front casing means.

8. The device of claim 1 wherein said transfer means includes a rod mounted in said forward portion of said housing member coaxial with and attached to said rotary drive shaft and extending into said front casing means, and said directional means includes gear means for coupling said rod with said rotary workhead.

9. A portable oral hygiene device comprising in combination:

a housing member with a longitudinal axis, including handle means for manually grasping said housing member, and having a forward portion and a rearward portion;

a rotary drive shaft mounted in said rearward portion on an axis substantially parallel to said longitudinal axis of said housing member, said rearward portion including back casing means for carrying therein a drive motor coupled to said rotary drive shaft;

a rotary workhead;

journal means in said forward portion of said housing member for rotatably and removably mounting said rotary workhead on said forward portion on an axis substantially perpendicular to said longitudinal axis of said housing member, said forward portion including small diameter front casing means for sealing said forward portion of said housing member from oral moisture, and transfer means inside said housing member coupling said rotary drive shaft with said rotary workhead for driving said workhead from said shaft, said transfer means including a front pulley in said front casing means connected coaxially with said workhead, and an endless belt engaged by said front pulley.

10. The device of claim 9 wherein said transfer means includes a back pulley connected coaxially with said drive shaft and engaging said endless belt, and directional means engaging said endless belt between said back and front pulleys for changing the direction of movement of said endless belt.

11. The device of claim 10 wherein said housing member includes means for removably attaching said forward and rearward portions of said housing member.

12. The device of claim 9 wherein said transfer means includes a back pulley mounted in said forward portion of said housing adjacent to and on an axis substantially perpendicular to said rotary drive shaft, and directional means coupling said back pulley with said rotary drive shaft.

13. The device of claim 12 wherein said housing member includes means for removably attaching said forward and rearward portions of said housing member.

14. The device of claim 9 wherein said front casing means includes Teflon washer means around said axis of rotation for sealing said forward portion of said housing member from oral moisture.

15. The device of claim 1 wherein said housing member includes means for removably attaching said forward and rearward portions of said housing member, and wherein said forward portion of said housing member includes control means connected to said drive motor for actuating said device only when said forward and rearward portions are attached together.

16. The device of claim 1 wherein said forward portion of said housing member includes a shaft carrying outer diameter of the shaft for fitting over and sealing the junction between said shaft and said front casing means with said inner edge coned slightly in the direcsaid rotary workhead and flattened washer means hav- 5 tion of said workhead-

Claims

1. A portable oral hygiene device comprising in combination: a housing member with a longitudinal axis, including handle means for manually grasping said housing member, and having a forward portion and a rearward portion, said rearward portion of said housing means including back casing means for carrying therein a drive motor coupled to said rotary drive shaft, and said forward portion of said housing means including small diameter front casing means for sealing said forward portion of said housing member from oral moisture; a rotary drive shaft mounted in said rearward portion of said housing on an axis substantially parallel to said longitudinal axis of said housing member; a rotary workhead; journal means in said forward portion of said housing member for rotatably mounting said rotary workhead on said forward portion on an axis extending laterally relative to said longitudinal axis of said housing member; and transfer means inside said housing member coupling said rotary drive shaft with said rotary workhead for driving said workhead from said shaft, including directional means for converting rotary energy about said axis of said rotary drive shaft into rotary energy about said axis of said rotary workhead.

9. A portable oral hygiene device comprising in combination: a housing member with a longitudinal axis, including handle means for manually grasping said housing member, and having a forward portion and a rearward portion; a rotary drive shaft mounted in said rearward portion on an axis substantially parallel to said longitudinal axis of said housing member, said rearward portion including back casing means for carrying therein a drive motor coupled to said rotary drive shaft; a rotary workhead; journal means in said forward portion of said housing member for rotatably and removably mounting said rotary workhead on said forward portion on an axis substantially perpendicular to said longitudinal axis of said housing member, said forward portion including small diameter front casing means for sealing said forward portion of said housing member from oral moisture, and transfer means inside said housing member coupling said rotary drive shaft with said rotary workhead for driving said workhead from said shaft, said transfer means including a front pulley in said front casing means connected coaxially with said workhead, and an endless belt engaged by said front pulley.

16. The device of claim 1 wherein said forward portion of said housing member includes a shaft carrying said rotary workhead and flattened washer means having an inner edge with a diameter slightly less than the outer diameter of the shaft for fitting over and sealing the junction between said shaft and said front casing means with said inner edge coned slightly in the direction of said workhead.