The present invention is directed to electric toothbrushes, and, more particularly, to a replacement head that is attachable to an electric toothbrush drive unit.
Recognizing that toothbrush bristles require periodic replacement, manufacturers have designed replacement heads to fit onto separate drive units of electric toothbrushes. The drive units typically include a power source, switch and a drive shaft. The replacement heads typically can be removably attached to the drive units by threading or snap-fitting a portion of the replacement head onto a portion of the drive unit.
Replacement heads typically include an elongated neck with an internal brush shaft connected to a bristle bearing head. The brush shaft is arranged to transfer power from the drive unit and drive shaft to the brush head for moving the brush head in a desired manner. Many brush heads are configured to transfer rotational movement of the drive shaft about a longitudinal axis into rotational or oscillatory movement of the bristle head about an axis that is perpendicular to the longitudinal axis of the drive shaft. Other brush heads are configured to move the bristle head about the same longitudinal axis as the drive shaft, or about an axis that is parallel to the longitudinal axis of the drive shaft. Each type of brush head generally includes a motion conversion mechanism for transferring the motion of the drive shaft into a desired motion of the bristle head that is effective at cleaning teeth and comfortable for a user.
The present invention provides a replacement brush head for an electric toothbrush with a motion conversion mechanism that provides an effective and user friendly bristle motion. In one embodiment, the motion conversion mechanism operates to move the bristle head about an axis that is generally parallel to the longitudinal axis of the drive shaft, while reducing the bristle travel angle and power—as compared to that of the drive shaft—to provide an effective and user friendly bristle motion.
In one embodiment, the replacement head includes a neck and a bristle head. The neck may be a generally hollow and may be fixed to a stationary portion of the drive unit. At least a portion of the bristle head may extend through the neck along a longitudinal axis that is aligned with the longitudinal axis of the drive shaft. A bristle base may be fixed to a distal end of the bristle head. The opposite end of the bristle head forms a brush shaft that receives the drive shaft.
In one embodiment, portions of the bristle head and the neck combine to form the motion conversion mechanism that converts rotary oscillation of the drive shaft into rotary oscillation of the bristles having a desired angular movement.
Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited to the details of operation or to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention may be implemented in various other embodiments and may be practiced or carried out in alternative ways not expressly disclosed herein. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. Further, enumeration may be used in the description of various embodiments. Unless otherwise expressly stated, the use of enumeration should not be construed as limiting the invention to any specific order or number of components. Nor should the use of enumeration be construed as excluding from the scope of the invention any additional steps or components that might be combined with or into the enumerated steps or components.
A replacement brush head for an electric toothbrush according to one embodiment of the present invention is shown in
The brush head 10 of the illustrated embodiment may be secured to the drive unit 142 by friction fit of components of the brush head onto the drive unit 142 and the drive shaft 140. Alternatively, the brush head may be coupled to the drive unit by threading or otherwise connecting a portion of the brush head onto a portion of the drive unit. Although the brush head 10 is described in connection with the particular drive unit 142 and drive shaft 140 shown in
As shown, the replacement brush head 10 includes a neck 30, and a bristle head 12 with a first end 22 and second end 24. In the illustrated embodiment, the first end 22 forms a bristle base 14. The bristle base 14 includes a plurality of holes 15 to facilitate the seating of tufts of bristles 16 on the bristle base 14. Alternatively, the bristle base 14 may be configured to receive other cleaning elements, such as elastomeric cleaning elements. In the illustrated embodiment, an optional bristle head overmold 18 is affixed to the base 14 on a side opposite the bristles. The overmold may be made from the same material as the bristle head 12. This can provide opportunity to vary colors of the bristle head and/or more easily allow space for brand identity or other labeling. Alternatively, the overmold 18 may be formed from a material that is different from the bristle head 12. For instance, the bristle head 12 may be formed from a rigid plastic material and the overmold may be formed from a resilient elastomer that may function as a soft tissue cleanser. The size and shape of the bristle base 14, and the placement, orientation and type of bristles or cleaning elements may be varied from application to application.
As illustrated, the second end 24 of the bristle head 12 forms a brush shaft 20 that extends into the neck 30 and receives the drive shaft 140 extending from the drive unit. The brush shaft 20 may be elongated in a direction parallel to the longitudinal axis 38 of the brush head 10, with a generally cylindrical outer surface. In the illustrated embodiment, the brush shaft 20 is an integral extension of the bristle base 14 (and formed from a single piece with the bristle base); however, in another embodiment the brush shaft 20 may be an independently formed component of the bristle head 12.
Referring now to
Referring now to
The neck 30 is a hollow, generally cylindrical body with openings at opposite ends for receiving the drive unit 142 at one end and the brush shaft 20 at the opposite end. At least a portion of the brush shaft 20 extends through the neck 30. In the illustrated embodiment, the bristle base 14 abuts the neck 30 when the brush head 10 is completely assembled. In one embodiment, an insert 32 extends into the neck 30 at the end opposite the brush shaft 20. The insert may be configured to interfit with a portion of the drive unit 142 to retain the brush head 10 on the drive unit 142 and prevent rotation of the neck 30 with respect to the drive unit 142.
The bristle head 12, overmold 18, neck 30 and insert 32 may be manufactured from polymers or resins such as, but not limited to, being molds of polyoxymethylene (“POM”) such as that available under the Tradename DURACON® from Polyplastics and referred to as polyacetal or acetal resin. The bristles 16 may be made from a variety of materials including, but not limited to nylon and polybutylene terephthalate (“PBT”). The bristles 16 may also be made from natural materials having an appropriate stiffness. The bristles 16 may be attached to the bristle base 14 in a number of ways including being stapled inside the holes 15 or by other known methods. The bristles 16 may be cut to various trim profiles, as desired. The stiffness of the bristles 16 may be controlled depending upon the feel desired in the mouth.
The brush head 10 is designed to operate in a manner that provides a user-comfortable range of motion of the bristles 16 by controlling the angle of travel 17 transferred from the drive shaft 40 to the brush shaft 20 as well as the torque of the brush shaft 20 when driven by the drive shaft 40.
During operation, the drive shaft 40 oscillates about an axis over its factory set travel range of rotation. However, the bristle carrier 20 may oscillate over a smaller travel range 17. As shown in
The increased angles beyond the D-shape of the hollow portion 25, or the gaps 27, 29 create slack, looseness, or float between the carrier 20 and the drive shaft 40. Further, during operation, the increased angle or gaps 27, 29 create a small delay of the carrier 20 rotation relative to the drive shaft 40 rotation. With a drive unit operating at about 5,000 RPM, the delay equates to a stall of about 15 ms per stroke on each side. A stall of this brevity is unperceivable, or at least unbothersome, by typical humans.
Advantages of the brush head shown and described herein include a reduced, compact angle of rotation 17 of the brush head 10. For example, if the input rotational angle as received from the drive shaft 40 is about 55-60° (27.5-30° from center), the output rotation of the carrier may be about 40° (20° from center). Additionally, due to the output angle and drive angle being of a ratio less than 1:1 without the use of gears or off-set shafts, the overall size of the brush head 10 may be reduced. The brush head 10 also allows for a reduced number of components required to produce similar results.
The angle of travel of the bristle head 12 may be further reduced, and the power transferred from the drive unit 42 to the bristle head 10 may also be reduced, by the flexibility created by the channels 26. The tab 28 on the second end 24 of the bristle head 12 may be held firm between the a portion of the neck 30 and the insert 32 to prevent rotation of the lower portion of the brush shaft 20. At the same time, the upper portion of the brush shaft 20, that is, the portion above the channels 26, may be allowed a degree of rotational movement. Thus, when the drive shaft 40 rotates as shown in
The above description is that of current embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. This disclosure is presented for illustrative purposes and should not be interpreted as an exhaustive description of all embodiments of the invention or to limit the scope of the claims to the specific elements illustrated or described in connection with these embodiments. For example, and without limitation, any individual element(s) of the described invention may be replaced by alternative elements that provide substantially similar functionality or otherwise provide adequate operation. This includes, for example, presently known alternative elements, such as those that might be currently known to one skilled in the art, and alternative elements that may be developed in the future, such as those that one skilled in the art might, upon development, recognize as an alternative. Further, the disclosed embodiments include a plurality of features that are described in concert and that might cooperatively provide a collection of benefits. The present invention is not limited to only those embodiments that include all of these features or that provide all of the stated benefits, except to the extent otherwise expressly set forth in the issued claims. Additionally, any of the features from one embodiment may be used in another embodiment. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular.
Filing Document | Filing Date | Country | Kind |
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PCT/US2015/012586 | 1/23/2015 | WO | 00 |
Number | Date | Country | |
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61931886 | Jan 2014 | US |