The field of the present disclosure relates in general to power-operated toothbrushes and, more particularly, to a toothbrush having powered bristle motion wherein the motive force for the bristle motion is provided by an energy storage device such as a torsion spring, that is loaded or charged by hand-winding; and to devices and methods for replacement of brush heads on powered toothbrushes.
In order to facilitate hygienic care of the teeth and gingival areas, a variety of power-operated toothbrushes have been developed and are currently available on the market. Typically, these power-operated toothbrushes comprise a battery and an electric motor coupled to mechanical linkages that drive the toothbrush head and/or groups of bristles back and forth, side to side, or in rotating motions to help dislodge plaque from tooth surfaces.
Recent developments in this field have been largely directed to increasing vibration frequencies—“ultrasonic” power brushes are now common. However, other features and characteristics of powered toothbrushes may also be of importance in particular situations. The present disclosure discusses embodiments that are useful in several circumstances.
Embodiments of the invention are powered toothbrushes that operate on user-supplied energy. The toothbrushes may have replaceable bristles or mechanical heads, and some embodiments include features to help prevent the user from applying excessive brushing force.
Additional aspects and advantages will be apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings.
Embodiments of the present disclosure include manually-charged powered toothbrushes and replacement brush heads for powered toothbrushes. Energy to operate such a toothbrush is typically loaded and stored mechanically, e.g. by manually-winding or compressing a spring, or by accelerating an inertial wheel by hand, but an embodiment might also use a manually-operated generator to charge a battery or storage capacitor, which would subsequently operate an electric motor to drive the brush bristles.
The body 110 may have a non-circular and/or nonuniform cross-section or a nonlinear central axis (i.e., it may bend or curve somewhat), provided that the internal mechanisms can be accommodated and other operational requirements can be met. Rotation between parts 140 and 150 may be unidirectional or bidirectional, as discussed below.
An embodiment comprises a bi-stable switch 160 to disable or enable the device. The switch may be, for example, a brake that engages an internal mechanism to prevent operation while the device is not in use (including when the device is being charged). When disengaged, the internal mechanisms turn and/or reciprocate to cause the brush to oscillate. Brushes may rotate back and forth around an axis of rotation, move back and forth along an axis of translation, sweep back and forth through an arc perpendicular to an axis of rotation, or make more complicated combinations of these and similar motions, all directed at more efficiently dislodging debris from the user's teeth and gums.
In a rotating-winder embodiment, a torque limiter 220 may be provided so that the user does not overcharge or overstress the device. A torque limiter may make a noise or display a visual indicator when the device is fully charged.
An input or winding gear train 230 couples the user's input winding action (via the winding control 210) into a suitable motion for charging the energy store. In a preferred embodiment, the user's winding performs work to compress a motor spring 240. For example, motor spring 240 may be a spiral or scroll spring in a cylindrical form factor, where twisting the spring around an internal spindle through the center of the cylinder stores energy in the spring.
A brake 250 may engage with another part of the motor spring 240 or with an output/drive gear train 260 to prevent the energy in the spring from immediately activating the device while the user is charging it. Once a sufficient charge has been applied (e.g., when the torque limiter 220 clicks to indicate that the spring 240 has been completely wound), the device is ready for use.
The user may disengage brake 250, allowing the braked component to operate freely. For example, the motor spring 240 may be freed to uncompress or unwind; or an output/drive gear train 260 coupled to the motor spring 240 may be permitted to move. Motion of the output/drive gear train causes the oscillating brush 270 to rotate, vibrate and/or translate through a reciprocating range. The oscillating brush helps the toothbrush's user to clean his teeth.
In a preferred embodiment, the output/drive gear train will have low friction (to avoid wasting energy from the motor spring). However, such an embodiment may drive its brush to oscillate too quickly, expending the stored energy before the user can complete his brushing regimen. In such an embodiment, it is preferred to include a speed limiter 280. For example, the inertial speed limiter described below can be used to prolong the device's operation at a useful oscillating rate, rather than dumping the full charge quickly in an unhelpfully rapid burst of oscillation.
Next, we turn to the structural details of each functional block, with particular attention to the specific implementation choices of the preferred embodiment.
Winding Mechanism
The preferred embodiment comprises a rotating winder that can be turned to compress an energy-storage spring. The axis of rotation may be aligned with the central cylindrical axis of the handle body. A curved-handle implementation may be constructed by offsetting and/or angling the axis of winding with respect to the next portion of the body housing (for example, by using a non-collinear gear train or a flexible axial joint such as a U-joint.
The preferred embodiment (
Input Gear Train
The “output” side of the Hirth coupling (plate 630) is secured to the outer or ring gear 640 of a planetary gear set (640, 650, 660). A plurality of planet gears 650 turn between the ring gear 640 and a sun gear (difficult to see in this view, but the output collet of the sun gear is visible at 660). The planetary gear set is constructed to multiply input rotations of the winding handle by a factor of between about 1.8 and about 8 (i.e., the gear ratio of the planetary gear set is from about 5:9 to about 1:8), and more preferably between about 2 and 8 (gear ratio of 1:2 to 1:8) or 1.8 and 4 (gear ratio of 5:9 to 1:4). Because of the configuration of the winding handle, each winding twist by the user rotates through about ½ turn of the Hirth coupling. The planetary gear set multiplies that to produce around 1 to around 4 turns for compressing the motor spring. The planetary gear ratio may be increased to reduce the number of turns required to compress the spring; or the ratio may be reduced to limit the torque required of the user on each winding turn. Cover 670 keeps the planetary gear set components together, and axle 680 delivers the rotation-multiplied winding twists to the next section of the device.
In one embodiment, the input gear train may be provided with a one-way clutch, such as a ratchet, one-way needle bearing/clutch, or other roller clutch, for example, between coupler 460 and ring gear 640, so that the user can make a charging twist, then rotate the handle back to its original orientation with negligible force so that it is ready for another charging twist. In another embodiment, the input gear train may be provided with two different gear paths, so that the motor spring is compressed by rotation of the handle in either direction. In a bidirectional charging embodiment, the gear ratio in each direction may be different, so that one direction charges with only a few high-torque twists, while the other direction requires more, lower-torque twists. Such an embodiment may be easily useable by both adults of ordinary grip strength, and children or infirm individuals who are unable to apply the ordinary torque to the winding mechanism.
The preferred embodiment is provided with a torque limiting mechanism, either between the winding handle and the input gear train (as shown in
Energy Storage
In a preferred embodiment, the motor spring is a constant force spring, sometimes called a constant torque spring or a constant torque power spring. Within its design operating range, a constant force or constant torque spring exerts a relatively consistent force against its load during most of its unwinding or energy-delivering operation, and preferably delivers at least 0.4 N-m of average torque and more preferably between 0.5 N-m and 0.8 N-m of average torque. A relatively constant torque output relaxes the design constraints on subsequent mechanical stages, which need not account for widely-varying power delivery as the spring winds down.
Output Gear Train
The multi-stage planetary speed multiplier (810, 820, 830) is coupled to an inertial speed limiter 850 (c.f.
A cap or cover 870 encloses the output gear train and speed governor, and forms a base to support the final brush-drive mechanism 880.
Speed Limiter (Governor)
Other embodiments of a speed limiter include a viscous damper in which an impeller or other devices moves within a viscous damping medium, and a friction damper.
Brake
Oscillating Brush
Finally,
Replaceable Brush Head
With reference to
A drainage slot 1240 is further provided along the rear side of neck 1210 to allow any water which may pass around hood portion 1220 and into neck 1210 to drain from neck 1210, and to prevent the retention of moisture therein. Draining slot 1240 also to allow the inside of neck 1210 to be washed by flushing clean water into and through it.
Toothbrush Performance
The input gear train 530, motor spring 540/spring motor module 710, and output gear train 560 are preferably designed to (a) fit within the generally cylindrical or tubular housing/body 110 that is sized for usability and ergonomics according to the foregoing description of body 110 and winding handle 440 (i.e. having a winding handle smaller than 35 mm in diameter), and (b) deliver sufficient output power and torque to provide at least 90 seconds of brush head oscillation, and preferably in excess of two full minutes of brush head oscillation run time, of at least 50 Hz or at least 60 Hz at the brush head (and more preferably between 50 Hz and 80 Hz), while at the same time being manually windable to achieve the desired run time with fewer than 10 winding twists (of 180-degrees or less for each twist), and preferably fewer than 4 twists, using hand strength in the range of 5 ft-lbs to 15 ft-lbs (6.8 N-M to 20.3 N-m) of input torque and more preferably between 5 ft-lbs and 12 ft-lbs (6.8 N-m to 16.3 N-m) of input torque.
An embodiment of the invention may comprise a spring; manually-operated winding means for compressing the spring; drive means for controllably releasing compression of the spring; and a brush coupled to the drive means so that the brush oscillates while the drive means is controllably releasing the compression of the spring.
An embodiment like the foregoing may further comprise a brake for preventing the drive means from controllably releasing compression of the spring while the brake is engaged.
The spring of an embodiment like the foregoing may be a motor spring.
An embodiment like the foregoing may have a winding means comprising a planetary gear set having a gear ratio between 1:2 and 1:8.
Another embodiment like the foregoing may have a winding means comprising a planetary gear set having a gear ratio between 5:9 and 1:4.
An embodiment like the foregoing may have a winding means comprising a torque limiter.
The torque limiter of an embodiment may be a Hirth coupling.
An embodiment like the foregoing may have a drive means comprising planetary gear set having a gear ratio between 1:350 and 1:450.
Another embodiment like the foregoing may have a drive means comprising planetary gear set having a gear ratio between 1:350 and 1:600.
The drive means of an embodiment like the foregoing may include an inertial speed limiter.
An embodiment like the foregoing may position the spring, the winding means, and the drive means, within a substantially cylindrical housing.
Another embodiment may comprise a roughly-cylindrical body having a lower portion, an upper end and a middle portion between said lower portion and said upper end, said upper end provided with a replaceable vibrating brush; a constant-torque spring disposed within the middle portion; an input gear train coupled between the lower portion and the constant-torque spring; an output gear train coupled between the constant-torque spring and the replaceable vibrating brush; and an output brake to prevent the output gear train from operating, wherein rotating the lower portion around an axis of the roughly cylindrical body with respect to the middle portion activates the input gear train to cause winding of the constant-torque spring; and disabling the output brake causes the constant-torque spring to drive the output gear train so as to activate the vibrating brush.
An embodiment like the foregoing may further comprise a speed governor coupled to the output gear train to limit a rate of operation of the output gear train to a predetermined rate.
An embodiment like the foregoing may further comprise a torque limiter coupled to the input gear train to prevent the input gear train from applying torque greater than a predetermined torque to the constant-torque spring during winding.
The torque limiter of an embodiment may be a Hirth coupling, or it may be a friction plate coupling.
An embodiment like the foregoing may have an input gear train comprising a planetary gear set to convert a first angular rotation of the lower portion of the roughly cylindrical body into a different angular rotation for winding the constant-torque spring.
An embodiment like the foregoing may use a ratchet to convert rotation in only one direction into winding of the internal spring.
The input gear train of an embodiment may convert rotation in either direction of the lower portion of the roughly cylindrical body into winding of the constant-torque spring.
In the input gear train of an embodiment, a first gear ratio of rotation in a first direction may be different from a second gear ratio of rotation in a second, different direction.
An embodiment may comprise a roughly-cylindrical housing having a central axis; a motor spring contained within the roughly-cylindrical housing; a winding cap at one end of the roughly-cylindrical housing, said winding cap capable of rotating around the central axis; a winding gear train comprising a first planetary gear set coupled between the winding cap and the motor spring, said winding gear train having a gear ratio from about 1:2 to about 1:8 and operative to convert a first angular rotation of the winding cap around the central axis into a second, different angular rotation of the motor spring; an oscillating brush coupled to another end of the roughly-cylindrical housing; a drive gear train comprising a second planetary gear set coupled between the motor spring and the oscillating brush, said drive gear train having a gear ratio from about 1:350 to about 1:450 and operative to convert a third angular rotation of the motor spring into an oscillating cycle of the oscillating brush; an inertial speed limiter coupled to the drive gear train to prevent a rate of rotation of the third angular rotation from exceeding a predetermined maximum rate of rotation; and a brake to prevent the drive gear train from operating to convert the third angular rotation of the motor spring into the oscillating cycle of the oscillating brush while the brake is engaged.
It will be apparent to those having skill in the art that many changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. Applications of the present invention have been described largely by reference to specific examples and in terms of particular allocations of functionality to certain mechanical structures and arrangements. However, those of skill in the art will recognize that a manually-wound, mechanically powered toothbrush can also be constructed differently than the preferred embodiments herein described. The scope of the present invention should, therefore, be determined only by the following claims.
This application is a continuation of U.S. application Ser. No. 16/361,145, filed Mar. 21, 2019, which is a continuation-in-part and claims priority under 35 U.S.C. § 120 to U.S. patent application Ser. No. 16/107,020 filed Aug. 21, 2018, which claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 62/559,325 filed Sep. 15, 2017. This application is also a continuation-in-part of and claims priority under 35 U.S.C. §§ 365(c) and 120 to International Application No. PCT/US2018/050386, filed under the Patent Cooperation Treaty on Sep. 11, 2018, and designating the United States of America, claiming priority to U.S. application Ser. No. 16/107,020 and 62/559,325. The disclosures of the foregoing applications are incorporated herein by reference in their entirety.
Number | Date | Country | |
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62559325 | Sep 2017 | US | |
62559325 | Sep 2017 | US |
Number | Date | Country | |
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Parent | 16361145 | Mar 2019 | US |
Child | 17222853 | US | |
Parent | 16107020 | Aug 2018 | US |
Child | PCT/US2018/050386 | US |
Number | Date | Country | |
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Parent | 16107020 | Aug 2018 | US |
Child | 16361145 | US | |
Parent | PCT/US2018/050386 | Sep 2018 | US |
Child | 16361145 | US |