US 3629944 A
Description (OCR text may contain errors)
United States Patent Edward A. Avakoff South San Francisco; Oliver G. Harris, San Francisco, both of Inventors Calif. Appl. No. 839,774 Filed June 17, 1969 Patented Dec. 28, 1971 Assignee Lord Corporation Continuation-impart of application Ser. No. 796,739, Feb. 5, 1969, now abandoned. This application June 17, 1969, Ser. No.
ROTARY IMPLEMENT 3 Claims, 9 Drawing Figs.
U.S. Cl 32/59, 1 5/2 8, 64/4 Int. Cl A6lc 17/00 Field of Search 15/22-24,
References Cited UNlTED STATES PATENTS 8/1938 Daviau 3/1942 Rogers 5/1954 Chaun 4/1969 Moyer 5/1970 Kidokoro et al.
FOREIGN PATENTS 5/1959 France Primary Examiner-Edward L. Roberts Attorney-Townsend and Townsend 310/74 15/28 X 15/23 X 15/28X 310/75 B 74 e 84 92 9O 70 F5 a e 3? 9 r-' 9 I4" 5 86 I 87 A I PATENTED M62819?! SHEET 1 UF 2 3629.944
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INVENTORS FIG EDWARD A. AVAKOFF BY OLWER e. HARRIS ATTORNEYS PATENTEU B5228 I971 SHEET 2 BF 2 INVENTORS EDWARD A. AVAKOFF BY OLIVER G. HARRIS ATTORNEYS ROTARY IMPLEMENT This application is a continuation-in-part of application Ser. No. 796,739, filed Feb. 5, I969, and now abandoned, entitled Rotary Implement."
This invention relates to hand-held power toothbrushes and, more particularly, to a toothbrush of this class which employs a rotating cup for cleaning bacterial plaque from the teeth.
Automatic toothbrushes have heretofore comprised handheld power units which move a brush either towards and away from the power unit or alternately rock the brush laterally with respect to the power unit. These brushing devices, while essentially duplicating the cleaning effect of the hand-held brush, do not serve to remove the bacterial plaque from all surfaced of the teeth of the user. As this bacterial plaque is the source and cause of substantially all tooth decay, its removal on a day-to-day basis is highly desirable in an applied program of dental hygiene.
Rotating rubber caps or buffers have long been used by dentists to effect removal of the bacterial plaque. Such rotating cups have been attached to a dentist's contraangle which in turn has been connected to a standard dentist's drill. Unfortunately, dentists drills are either powered by high-pressure air, which is not available in the home or alternately comprise permanently mounted motors, arms and associated belt drives wholly impractical for home use as they are too expensive and bulky.
An object of this invention is to disclose a portable toothbrush using a rotating cup or buffer suitable for removing bacterial plaque from the teeth in the home.
A further object of this invention is to disclose an adapter which will couple the casing of a standard dentist's contraangle to that of a hand-held motor so that the contraangle and motor become a single unitary mouth-working tool capable of placing a rotating tooth cleaning implement, such as a dentist's cup or point in the mouth of the user.
A specific object of this invention is to disclose a sleeve connection fitting which will hold the contraangle in coaxial relation relative to the rotating chuck on a hand-held motor so that rotary power can be transmitted to the tooth cleaning implement as well as brace the contraangle rigidly in a position where it can reach all teeth within the mouth for cleaning.
An advantage of this invention is that the contraangle and drill motor are readily separable one from the other to enable home replacement of worn parts of the toothbrush.
A further object of this invention is to disclose a coupling which is expansible longitudinally of its axis of rotation permitting the conjoinder of a single drill motor with dentists contraangles having shafts of varying length.
An advantage of the expansible coupling of this invention is that it can impart the rotational stability of the contraangle to a low-cost, miniature, high-speed electric motor, which motors commonly have bearings of relatively poor quality.
A still further object of this invention is to couple the output shaft of a hand-held motor to a relatively heavy flywheel incorporated within the couplings between the contraangle and hand-held motor.
An advantage of this flywheel within the coupling is that it can store the rotational energy produced by a low-cost, miniature, high-speed, electric motor to cushion the effect of the variable resistance of the rotating cup in the mouth and prevent destruction of the motor armature.
Other objects, features and advantages of this invention will become apparent as the following specification progresses, reference being had to the accompanying drawings for an illustration of two embodiments of the present invention.
In the drawings:
FIG. I is an elevational view of the portable toothbrush of this invention;
FIG. 2 is an expanded partial side elevation section of FIG. 1 illustrating specifically the joinder of the contraangle to the drill motor by way of an elastic sleeve;
FIG. 3 is a plan view of the elastic sleeve;
FIG. 4 is an elevational view of the elastic sleeve;
FIG. 5 is a partial section of the point of joinder between the rotating shaft of the contraangle and rotating chuck of the drill motor;
FIG. 6 is a partial side elevation section of an alternate embodiment of this invention showing an inside sleeve for coupling of the contraangle to a battery power motor;
FIG. 7 is a side elevation of yet another embodiment showing the conjoinder of a contraangle to a battery-powered motor;
FIG. 8 is an extended side elevation section of a coupling for conjoining the contraangle with a low-cost, miniature highspeed motor, the coupling being expansible longitudinally of the common axis of rotation of the contraangle and motor; and,
FIG. 9 is a plan view of the coupling taken along lines 9-9 of FIG. 8.
With specific reference to FIG. I, the portable toothbrush is shown comprising a hand-held motor A, a standard dentists contraangle C and an interconnecting sleeve B. Sleeve B functions to fasten the outside casing of the motor I4 to the outside casing of the contraangle 16 so that the contraangle is maintained in a rigid unitary relation with respect to motor A. Rotary power is transmitted from motor A at chuck 20 to contraangle C at shaft 24 to rotate a tooth-cleaning implement such as rotary cup D for cleaning and removing the bacterial plaque from the teeth.
Motor A is a standard item of manufacture. The motor A here illustrated is a hand-held drill motor, commonly used to hold and power drills of relatively small dimension. The motor must be capable of being hand-held and so insulated that the possibility of electrical shock to the human person is eliminated. The motor shown here is actuated by electrical current received through a cord and includes an outer casing 14, an actuating switch 18 and a rotating chuck 20. Chuck 20, shown in section in the view of FIG. 5, has a plurality of resiliently mounted jaws 42 which are compressed by a chuck tightening nut 44 fastening over the jaws 42 so as to move the jaws inwardly for grasping a shaft inserted therein.
Contraangle C is another standard item of manufacture. This contraangle has an outer casing I6, a lower shaft 24 and a rotary cup D protruding outwardly at the upward end thereof at right angles to the longitudinal axis of the casing I6. The contraangle is constructed so that shaft 24 extends beyond casing 16 of the contraangle where it receives and transmits rotary power through bevel gears in the upper portion of the contraangle so as to rotate cup D.
Sleeve B is designed to frictionally grasp motor A at casing I4 and contraangle C at lowered knurled surface 25 on its casing I6 to rigidly fasten the contraangle and motor into a single unitary working tool. In order to receive rotary power, shaft 24 of contraangle C is held by sleeve B in coaxial relation relative to the chuck mechanism 20. Moreover, it can be seen that the sleeve, in combination with that end of the motor casing adjacent the chuck disposes the outward end of the contraangle at a location where it can extend to all teeth within the human mouth. Further, the sleeve simultaneously prevents rotation of the contraangle casing 16 relative to the motor casing 14 and effects a firm fastening to eliminate all wobble of the rotating cup D relative to the motor A when the mouthworking tool is in use. In the embodiment illustrated, connecting sleeve B fastens the casing 14 of the motor to the casing 16 of the contraangle at an interval where the chuck mechanism is free to rotate therebetween.
Sleeve B comprises three main portions. There is an upper sleeve section 30 which is cylindrical in shape and has an inside diameter slightly less than the outside diameter of contraangle casing 16 at knurled surface 25. Similarly, there is a lower sleeve section 32 which has an inside diameter slightly less than the outside diameter of motor casing I4 immediate chuck mechanism 20. Extending between upper section 30 and lower section 32 there is a conical section of the sleeve 33. This section serves to physically interconnect the upper and lower sections and provide interiorly thereof an inside dimension which the chuck mechanism 20 of the motor is free to rotate without rubbing on the inside surface of the sleeve.
Sleeve B, illustrated in the instant disclosure is fabricated of a rigid elastic material such as steel, plastic, or the like. While it should be apparent that numerous methods of interconnecting the motor and contraangle could be applicable to the instant disclosure, the friction fitting provided by sleeve B is preferred as it simultaneously provides the required rigid interconnection of the contraangle and motor as well as a mouth-working tool which can be disassembled by hand for the replacement of worn parts.
As illustrated in FIGS. 1 and 3, sleeve B is provided with four longitudinally extending slots 37-40, which facilitate the radial and elastic expansion of the upper sleeve section 30 and lower sleeve section 32. A first expansion groove 37 (shown in FIG. 1) is cut longitudinally of sleeve B so as to separate the walls of the sleeve longitudinally through lower sleeve section 32, conical sleeve section 33 and upper sleeve section 30. Additionally, lower sleeve section 32 and conical sleeve section 33 are here provided with additional slots, 38, 39 and 40 running longitudinally through their walls at 90 intervals relative to groove 37. These slots allow relatively large elastic expansion of lower sleeve section 32 so that it can radially expand for efficient grasping of that portion of casing 14 adjacent chuck 20.
Assembly of the contraangle C to motor A is provided by first inserting the contraangle interior of upper sleeve section 30 and sliding the sleeve upwardly and over the casing I6 of the contraangle in the direction of the rotating cup D. Thereafter, the shaft of the motor is inserted interior of the jaws of the chuck shown at 42 (shown in FIG. Chuck tightening nut 44 is rotated so as to move the jaws of the chuck inwardly for grasping the shaft firmly.
Once the shaft 24 and chuck are firmly engaged, sleeve B is moved downwardly to a position where its upper section grasps the periphery of the contraangle case 16 at knurled surface 25 and its lower sleeve section 32 grasps the periphery of motor casing 14 in the vicinity of chuck 20.
In operation, sleeve B will maintain casing 14 and contraangle 16 in firm unitary relation. Shaft 24 will accept the rotary power of the motor A and impart this motion to the buffer cup D. As is apparent, by manipulating actuating switch 81, controlled rotary movement of cup D can be attained.
It has been found that for home use buffer cup D should be rotated at a speed between 300 and 2,000 r.p.m. These speeds are sufficient for removal of the bacterial plaque accumulated on teeth.
With reference to FIG. 6, an alternate embodiment of this invention is illustrated showing the conjoinder of a contraangle C to a battery-operated motor E by an inside of sleeve B. Sleeve B differs from sleeve B in that it frictionally interconnects the inside of casing 16 to the inside of casing 14' of the battery-operated motor E.
Similar to motor A previously illustrated, battery power drill E comprises a hand-held item of standard manufacture having an outside casing 14, a battery-powered motor 45 interior thereof with a protruding shaft 54. A distinguished from motor A, battery powered motor E is powered preferably by a low voltage internal power source which, even with the breakdown of insulation thereof, cannot communicate an electrical shock to the user of the tool of any appreciable or harmful magnitude. The battery-powered motor E is provided with a conically tapered housing over the shaft of the motor which defines a narrow circular sleeve 65 at the upward portion thereof. Sleeve 65 is the member to which the interconnecting sleeve B frictionally fastens for the conjoinder of the contraangle and motor.
Contraangle C is a standard item of manufacture, precisely analogous to the contraangle C illustrated in FIGS. I, 2 and 5. This contraangle differs from the contraangle previously illustrated in that it has a central shaft 50 which protrudes downwardly interior of the casing 16' terminating within the casing interior of the lower portion thereof adjacent knurled surface 25. As can be seen, the casing 16 defines an internal surface 51 into which sleeve B can be frictionally inserted for conjoining the contraangle and battery-powered motor E into a single unitary mouth-working tool.
Regarding sleeve B, this sleeve, fabricated of an elastic material such as plastic, nylon, or the like has an upper portion 53 and a lower portion 54. Upper portion 53 has an inside diameter slightly exceeding the internal diameter of casing 16' of contraangle C at surface 5 l. Similarly, lower portion 54 has an outside diameter slightly exceeding the inside diameter of the casing of the battery-powered motor E at surface 65. in the specific example here illustrated, both the contraangle casing 16 at surface 51 and the casing of battery-powered motor E at surface 65 have approximately the same internal diameter and the sleeve the same external diameter at both the upper portion 53 and the lower portion 54.
In addition to the frictional interconnecting of the respective casings of the contraangle and battery-powered motor, it is also necessary to interconnect the shaft 54 of the motor to the shaft 50 of the contraangle. A nylon sleeve 52 effects this interconnection.
Regarding this connection, nylon sleeve 52 expands outwardly at the upper portion thereof and defines a small concentric aperture 55 which frictionally slips over and grasps the outside surface of contraangle shaft 50. As fastened to the contraangle shaft, the sleeve extends downwardly from the shaft to a male coupling member 56 at the lower portion thereof. Male member 56 in turn fastens into a female coupling member 60. This member defines an aperture complementary to the outside dimension of the male coupling member 56 and fastens at its lower end to shaft 54 and handheld motor E.
To assemble the tool, sleeve B is forcibly inserted at upper portion 53 of interior of contraangle C at surface 51. Similarly, sleeve 52 is forcibly inserted over the shaft 50 of the contraangle at concentric aperture 55.
Once the connections of the sleeve B and the nylon sleeve 52 have been made, contraangle C is forcibly inserted over battery-powered motor E. Sleeve B fits at its lower portion 54 interior of surface 65 defined by the upper portion of the casing. Simultaneously with this fit, lower portion 56 of the shaft connecting sleeve 52 fits interior of the female coupling member 60. This internal connection couples the shaft 54 of the motor to the shaft 50 of the contraangle enabling rotary power to be communicated to the cup D.
Similar to the combination of the contraangle and motor shown in FIG. I, it should be apparent that the contraangle C and battery powered motor E can be interconnected by a variety of mechanical devices, the only limitation being that these devices firmly interconnect the contraangle and motor and allow the transmission of rotary power therebetween.
In the construction of dental implements for use in the home, two problems are commonly encountered. First, contraangles are commonly found having protruding shafts of varying length (the shaft illustrated in FIGS. 5 and 6 showing such variation). Secondly, in order to provide a low-cost dental implement, it is frequently desirable to use inexpensive, miniature, high-speed electric motors having bearings subject to some vibration, especially after extended use. These respective difficulties can be minimized by the improved coupling G illustrated in FIGS. 7-9 and shown conjoining batterypowered motor A to a dentists contraangle C.
Referring specifically to FIG. 8 the casing 14" of the battery-powered motor A at its upward end defines a cylindrical aperture 70 having inside sidewalls 71. Interior of the casing 14 there is a battery-powered motor 45 having a protruding shaft, extending into the cylindrical aperture 70.
Interconnection of contraangle C to hand-held motor A is provided by a sleeve B". Sleeve B" has a lower cylindrical portion 73 for attachment to hand-held motor A, an upper cylindrical portion 73 for attachment to contraangle C, and a frustum-shaped section 75 therebetween. Unlike sleeves B and B previously illustrated, sleeve B"is a single, rigid, unitary member and is not slotted at any portions thereof.
The lower cylindrical portion 73 of the sleeve has outside cylindrical sidewalls of a diameter slightly less than the inside cylindrical diameter of sidewalls 71 of aperture 70. Typically, rigid attachment of the sleeve is provided by a setscrew 76 threadedly mounted through casing 14" of hand-held motor A. Threaded movement of setscrew 76 into and out of aperture 70 will cause the end of the setscrew to bear against the outside sidewalls of the lower cylindrical portion 73 causing the sleeve to be rigidly fastened interior of the casing of handheld motor A.
Attachment of contraangle C to sleeve B" is here illustrated as a friction lift. Typically, the contraangle outside casing 80 is slotted at its lower cylindrical portion. A first slot 81 extends circumferentially of the contraangle casing opening a slot approximately rs its total circumference. A second longitudinal slot extends from the medial portion of circumferential slot 81 downwardly and parallel to the inner rotating shaft of the contraangle. These slots in combination bifurcate the lower portion of the contraangle into first and second radially expansible sections, which sections can elastically and frictionally girp sleeve B" at its upper cylindrical portion 74.
Sleeve B" at upper cylindrical portions 74 has an outside diameter slightly exceeding the inside diameter of the contraangle outside casing 80. As is apparent, when the contraangle is frictionally inserted over upper cylindrical portion 74, the two wings defined by the slots 81 and 82 respectively are biased radially outwardly and effect a firm frictional attachment of the contraangle C to the sleeve.
The longitudinally expansible coupling G used comprises an upper coupling member for gripping the contraangle shaft and a lower coupling member 86 attached rigidly to shaft 87 of the motor 45. Lower coupling member 86 is cylindrical in shape and to permit unrestricted rotation has an outside diameter less than the inside diameter of cylindrical aperture 70 of the hand-held motor. Member 86 is typically permanently attached to shaft 87 of motor 45 along its cylindrical axis and defines at the upward portion thereof a flat, circular surface 88.
Protruding upwardly from surface 88 on either side of the rotational axis of the lower coupling member 86 there are two upwardly extending pawls 90. Pawls 90 are each cylindrical, aligned parallel to the axis of rotation of the shaft 87 of motor 45, and spaced equidistantly outward of the axis of rotation at 180 intervals.
Upper coupling member 84 is a solid member, typically metallic, having a frustum-shaped base 92 and an upwardly extending chuck portion 94. Chuck portion 94 has an inside diameter slightly less than the outside diameter of the contraangle C shaft and is slotted longitudinally at four intervals in the sidewall of the cylinder. This separates the sidewalls of the chuck into four separate members which can be biased towards and away from the contraangle shaft so as to afford a firm frictional connection.
F rustum-shaped base 92 at its lower surface overlies and is coextensive with surface 88 of lower coupling member 86. This frustum vanishes into chuck portion 94 at its upward surface and has configured therein two cylindrical concavities 98. These concavities have a diameter greater than the diameter of pawls 90 and are spaced so as to capture pawls 90 when upper coupling member 84 is inserted on top of lower coupling member 86. Similar to the sidewalls of pawls 90, the sidewalls of concavities 98 are parallel to the axis of rotation of the motor and contraangle.
As is apparent, pawls 90 contact the cylindrical concavities 98 over a substantial length of the pawls. This length permits the coupling to maintain its respective members in substantial coaxial relative rotation.
It will also be apparent that upper coupling member 84 can be moved towards and away from contraangle C. In such movement, pawls 90 will contact the cylindrical concavities 98 and maintain upper coupling member 84 in a position of coaxial rotation relative to lower coupling member 86. It will be noted that this movement will be limited only by the length of the pawls and the contact of the frustum-shaped base 92 with the frustum-shaped section 75 of sleeve B".
The interconnection between hand-held motor A and contraangle C by the coupling of this invention has a feature not immediately apparent. Typically, contraangles of the variety illustrated have bearings therein which impart relatively good rotational stability to the downwardly protruding shaft. Unfortunately, miniature, high-speed motors do not have this same rotational stability; after extended use such motors tend to vibrate, losing speed and output power.
The improved coupling G herein illustrated grips the downwardly protruding shaft of the contraangle firmly. This coupling imparts the rotational stability of the contraangle shaft to the motor. Consequently, with the combination of this coupling, relatively inexpensive, miniature, high-speed motors can be provided with rotational stability providing an extended lift without loss of speed and power. It will be noted that coupling members 86 and 92 are herein described as solid members and are typically fabricated of a relatively dense material such as steel, brass, and the like. These coupling members when set in rotation by the attached motor store the kinetic rotational energy of the motor due to their flywheel effect.
This storage of kinetic rotational energy assures that the cup rotates at a substantially constant speed despite the variable friction forces experienced by the rotating cup in passing over the surfaces of the teeth. Moreover, the flywheel effect provided by coupling members 86 and 92 assures that the attached high-speed motor rotates at a speed wherein the individual windings of the armature will not draw excessive current and become shorted. This feature is especially necessary where low cost, high-speed electric motors are utilized.
These and other modifications of our invention may be practiced, it being understood that the form of our invention as described above is to be taken as a preferred example of the same. Such description has been by way of illustration and example for purposes of clarity and understanding. Changes and modifications may be made without departing from the spirit ofour invention.
1. A hand-held rotary dental appliance comprising: an elongated housing, a motor mounted within said housing having a rotatable shaft disposed in axial alignment with the longitudinal axis of said housing, a balanced, weighted flywheel nonrotatably mounted on said shaft, a first end of said flywheel formed with a flat surface disposed normal to the axis of said shaft and a pair of pins projecting outwardly therefrom normal to said surface, a coupling member mounted on the first end of said flywheel having a surface formed with a flat face having a diameter the same as the first end of said flywheel disposed in juxtaposition with the surface on the first end of said flywheel, a pair of grooves formed in said coupling member in registration with said pins to allow torque transfer of said pins to said coupling member while allowing said coupling member to be free to move longitudinally relative to said flywheel, an implement-engaging cup mounted rigidly on said coupling member in axial alignment with said motor shaft, a dental working instrument having a shaft longitudinally mounted relative to said housing and axially aligned with the shaft of said motor to frictionally engage with said cup member for transference of torque.
2. A hand-held rotary dental appliance according to claim 1 and wherein power means are mounted within said housing connected to energize said motor.
3. A hand-held rotary dental appliance according to claim 1 and wherein said housing is formed in two parts, the first of said parts including the motor and said flywheel and the second of said parts including said coupling member and said dental working instrument, each of said parts being removably mounted with respect to each other.