EP-4736810-A1 - ATTACHMENT PORTION OF A REPLACEMENT BRUSH HEAD

EP4736810A1EP 4736810 A1EP4736810 A1EP 4736810A1EP-4736810-A1

Abstract

A replacement brush head is provided for a robust snap-fit attachment to an electric toothbrush handle. The replacement brush head includes a tubular body with a bristle carrier disposed on a first end. The second end includes structure for attaching the tubular body to an attachment portion of the handle. This attachment structure may include a pair of spaced apart, resilient retention bars extending parallel to the longitudinal axis, with each of the resilient retention bars including first and second ends connected to the tubular body, and each of the resilient retention bars including a clamp portion positioned between the first and second ends and capable of flexing with respect to the first and second ends.

Inventors

DISHON, BRYAN J.

Assignees

Ranir, LLC

Dates

Publication Date: 20260506
Application Date: 20251022

Claims (14)

A replacement brush head for attachment to an electric toothbrush handle comprising: an outer sleeve with a first end and a second end opposite the first end, the outer sleeve defining a longitudinal axis; a bristle carrier disposed on the first end of the outer sleeve, the bristle carrier having a bristle surface, the bristle surface supporting a plurality of bristles extending outwardly from the bristle surface, the bristle carrier configured to rotate with respect to the outer sleeve about a cleaning axis extending at an angle to the longitudinal axis; and a coupling insert disposed within the second end of the outer sleeve, the coupling insert including at least one resilient retention bar, the at least one retention bar including a first portion connected to the coupling insert, a second portion connected to the coupling insert, and a clamp portion positioned between the first and second portions and capable of flexing with respect to the first and second portions, the retention bar positioned to engage and receive a portion of the handle upon insertion of the portion of the handle into the coupling insert.
The replacement brush head of claim 1, wherein the at least one resilient retention bar includes a pair of retention bars spaced apart and defining a channel therebetween.
The replacement brush head of claim 1 or 2, wherein the clamp portion of at least one of the retention bars is shaped to correspond to an exterior shape of the portion of the handle.
The replacement brush head of any of the preceding claims, wherein the clamp portion of the at least one of the retention bars is concave.
The replacement brush head of any of the preceding claims, wherein the clamp portions of both of the retention bars are mutually opposing concave shapes.
The replacement brush head of any of the preceding claims, wherein the coupling insert includes an upper end adjacent the first portion, and a lower end adjacent the second portion.
The replacement brush head of any of the preceding claims, wherein the each of the retention bars include an upper portion, the clamp portion, and a guide portion, the upper portion extending from the first portion of the retention bar to the clamp portion, the guide portion extending from the second portion of the retention bar to the clamp portion.
The replacement head of claim 7, wherein the guide portions of the retention bars converge toward one another from the second portions of the retention bars to the clamp portion, such that the guide portions of the retention bars can act to guide the coupling pin into the clamp portion as the replacement head is attached to the electric toothbrush handle.
The replacement head of claim 7 or 8, wherein the upper portions of the retention bars are generally parallel to one another.
The replacement head of any of claims 7 to 9, wherein the clamp portions each include an upper end adjoining the upper portion and lower end adjoining the guide portion, and wherein a portion of the clamp portions are spaced apart from each other a first distance, and wherein the lower ends of the clamp portions are spaced apart from each other a second distance, the first distance greater than the second distance such that the coupling pin snap fits into the clamp portion.
The replacement head of any of the preceding claims, wherein the retention bars include interior coupling surfaces facing each other and exterior surfaces opposite the interior surfaces, the coupling insert defining first and second flex channels, the flex channels extending along the exterior surfaces.
The replacement head of any of the preceding claims, including structure for connecting the coupling insert to the outer sleeve and retaining the coupling insert within the outer sleeve.
The replacement head of claim 12, wherein the structure for connecting the coupling insert includes a pair of protrusions extending from the coupling insert, the protrusions aligning with and extending into openings in the outer sleeve upon insertion of the insert into the outer sleeve.
The replacement head of any of the preceding claims, connected to an attachment stem extending from the handle, the attachment stem including a sidewall, a rib extending outwardly from the sidewall, an intermediate portion of the rib having a cylindrical shape and forming the portion of the handle engaged with the retention bars in the manner of a coupling pin.

Description

BACKGROUND OF THE INVENTION The present invention relates to electric toothbrushes, and more particularly to a replacement brush head that is attachable to an electric toothbrush drive unit, and a structure for connecting an outer sleeve portion of the replacement brush head to a static portion of the electric toothbrush drive unit. Recognizing that toothbrush bristles require periodic replacement, manufacturers have designed replacement brush 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 brush 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 brush heads typically include an elongated neck with an internal brush shaft connected to a bristle bearing head or bristle carrier. The brush shaft is arranged to transfer power from the drive shaft to the brush head for moving the brush head in a desired manner. One particular style of brush head is configured to convert alternating linear movement of the drive shaft along a longitudinal axis into rotational or angularly oscillatory movement of the bristle head about an axis that is perpendicular to the longitudinal axis of the drive shaft. These brush heads commonly include a fixed outer sleeve having the bristle bearing head at one end and an attachment portion at the opposite end. The brush head includes internal components within the outer sleeve for mating with the drive shaft, converting the motion, and driving the bristle carrier. The outer sleeve typically includes structure at the attachment end for connecting to a fixed portion of the drive unit in a manner that reliably retains the brush head in place on the drive unit during use while also enabling relatively easy removal and replacement by the user. One example of such an attachment is shown in US Patent 10869743 to Fritsch. In this example, the drive unit includes a generally cylindrical coupling stem having a sidewall and a free end. The linearly alternating drive shaft extends from the free end. A coupling pin extends outwardly from the sidewall to form a structure for interfitting with the outer sleeve of the brush head. The outer sleeve of the brush head includes a coupling insert that is configured to snap fit with the coupling pin via a pair of curved, laterally extending opposing cantilevered arms. These arms are capable of flexing in order to provide a reliable snap fit connection with the drive unit, but may be breakable and difficult to manufacture due to their curved, elongated nature. SUMMARY OF THE INVENTION The present invention provides a replacement brush head for a robust snap-fit attachment to an electric toothbrush handle of the style that includes an attachment portion with a sidewall, and a pin extending outwardly form the sidewall. In one embodiment, the replacement brush head includes a tubular body with a first end and a second end opposite the first end, and the tubular body defines a longitudinal axis. A bristle carrier is disposed on the first end, the bristle carrier having a bristle surface supporting a plurality of bristles, the bristle carrier configured to rotate with respect to the outer sleeve about a cleaning axis extending at an angle to the longitudinal axis. The second end of the tubular body may include structure for attaching the tubular body to the attachment portion of the handle. This attachment structure may include a pair of spaced apart, resilient retention bars, with each of the resilient retention bars including first and second ends connected to the tubular body, and each of the resilient retention bars including a clamp portion positioned between the first and second ends and capable of flexing with respect to the first and second ends. The retention bars are spaced apart from one another such that they engage and receive the coupling pin upon insertion of the attachment portion of the handle into the second end of the tubular body with the pin radially aligned between the retention bars. In one embodiment, the tubular body includes an outer sleeve and a coupling insert that is disposed in the second end of the outer sleeve, wherein the coupling insert includes the attachment structure. The coupling insert may include an upper end positioned within the outer sleeve, and a lower end positioned adjacent to the second end of the outer sleeve, the coupling insert including an upper section adjacent the upper end, and a lower section adjacent the lower end. The retention bars may include an upper portion, the clamp portion, and a guide portion, the upper portion extending from the first end of the retention bar to the clamp portion, the guide portion extending from the second end of the retention bar to the clamp portion. In one embodiment, the clamp portions of the retention bars are shaped to match the shape of the coupling pin,