COUPLING SECTION FOR PERSONAL-CARE IMPLEMENT AND PROCESS OF MAKING SAME, INCLUDING TOLERANCE COMPENSATION

A coupling section for coupling a handle of a personal-care implement and a replaceable attachment tool includes a drive shaft having a free end terminating in a bushing; a first magnetic coupling element mounted adjacent to the bushing; a tolerance-compensation element having a through-hole sized to receive the drive shaft therethrough and mounted adjacent to the bushing. The free end of the drive shaft is disposed in the bushing so that there is a space between an inner surface of the bushing and an outer surface of the drive shaft's portion disposed therein, so that a position of the drive shaft can be adjusted inside the bushing during assembly. The tolerance-compensation element, which at least partially encircles the drive shaft, is affixed to the drive shaft and to the bushing. A handle of the personal-care implement and a process of making the handle are also disclosed.

FIELD OF THE INVENTION

The present disclosure is concerned with the mass manufacturing of multi-component personal-care implements, such as, e.g., personal-care devices, including electric toothbrushes.

BACKGROUND OF THE INVENTION

Mass production of multi-component personal-care implements, such as, e.g., toothbrush handles and other similar items, are typically made by a multi-step processes that often require mass manufacturing of multi-component parts, which will later be assembled into the finished articles. These multi-components parts, to function as designed, must have uniform, virtually identical (within acceptable variations), size and shape. The requisite uniformity among the parts that are required to be identical can be defined by the extent to which minute variations in corresponding shapes and sizes among such mass-produced identical parts can be tolerated. The concern for uniformity is particularly important when multi-component parts that are required to be identical are manufactured at multiple locations, which may have somewhat different manufacturing conditions, equipment, and suppliers of the requisite material.

For example, virtually all plastic materials, to be molded into required parts, after having been heated to be liquefied and then cooled and solidified during the manufacturing process, typically shrink during cooling (a phenomenon commonly known as “mold shrinkage”), thereby reducing at least some of the resulting parts' physical dimensions from the ideal or nominal dimensions—and thus potentially causing lack of uniformity among these plastic components. Also, metal parts may experience deformation caused by welding during assembly of the required parts, which may affect uniformity among those parts. At the same time, the exact positioning of the requisite parts is required to enable a reliably stable process of their assembly into a finished product.

Therefore, variations from the ideal or nominal shape and sizes of the parts being assembled into a finished implement need to be within acceptable ranges of tolerances. As used herein, the term “tolerance” refers to an acceptable (tolerable) amount of variation of a specified shape and/or measurable dimension from the ideal/nominal shape of a part of the implements being assembled. As no item or any of its parts can be produced having shapes and dimensions precisely to the exact nominal value, tolerances are typically assigned to parts for manufacturing purposes, as boundaries for acceptable build. Hence, there are degrees of acceptable variation/deviation from the exact nominal value, suitable for a particular machine, process, or part. Tolerances can be applied to any shape and dimension. A manufactured part having the shape and/or dimension that exceed the tolerance will be unlikely a usable part for the intended purpose.

The successive assembly steps require a correct positioning of the parts being assembled. To accomplish this, the manufacturer needs to ensure that the size and geometry of all elements, including the parts being manufactured/assembled, match one another with a high-degree precision, requiring strict tolerances. These strict tolerances are often hard to achieve, particularly in the context of mass production of the components that may take place at various locations and under different business and environmental conditions, as is previously mentioned.

Such mass production requires multiple tools, including, e.g., mold tools and components, which are typically installed on different machines and which are intended for making identical parts. For example, for the production of a handle for a personal-care tool, such as, e.g., an electric brush, which is typically designed to house a plurality of components (including, e.g., a motor, a battery, electronics, and a drive unit including at least a portion of a drive shaft, as well as to have other structural and functional attributes), the reliable uniformity and precision among the different tools and equipment parts are of high importance for the goal of achieving, and remaining within, the requisite tolerances.

SUMMARY OF THE DISCLOSURE

The present disclosure is directed to addressing the problem of comforting the required tight tolerances in multi-component personal-care implements. This is done by providing a coupling section and a handle for a multi-component personal-care implement, which coupling section includes a novel functional element—a tolerance-compensation element—that would allow manufacturers to appreciably relax otherwise strict tolerances for certain parts and manufacturing processes, while maintaining the requisite reliability and functionality of the parts being produced and assembled. The present disclosure, therefore, offers a novel coupling section and a handle for a mass-produced multi-component personal-care implements, as well as a more reliable and stable process of manufacturing and assembling parts required for such mass- produced multi-component personal-care implements.

In one aspect, the present disclosure is directed to a coupling section for a personal-care implement. The coupling section comprises a drive shaft that has a longitudinal axis and a free end. The personal-care implement may have any suitable operation frequency. In one example embodiment, the drive shaft can be configured to have an operation frequency of from about 50 Hz to about 270 Hz. The coupling section may include at least one first magnetic coupling clement mounted adjacent at the free end of the drive shaft for connection, by magnetic interaction, with at least one second magnetic coupling element of a replaceable attachment tool. In the context of oral-care, such replaceable attachment tool may comprise a movable (e.g., vibrating, rotating, oscillating) brush head.

In one example embodiment, the coupling section has a cap having a longitudinal axis L2and comprising a tubular structure. The cap has a first (open) end and a second end opposite to the first end. The cap may house the at least first magnetic coupling element that is disposed adjacent to the second end of the cap. The handle further may comprise a bushing having a first (open) end and a second end opposite to the first end. The bushing can be fixed inside the cap to be adjacent to the first end of the cap so that the first end of the bushing is adjacent to the first end of the cap.

A tolerance-compensation element can be arranged at the first end of the bushing. The tolerance-compensation element has a through-hole that is sized to receive the drive shaft therethrough. The drive shaft is inserted, through the tolerance-compensation element, into the bushing and is affixed to the drive shaft and to the bushing.

The bushing can be beneficially sized to loosely receive therein a portion of the drive shaft, so that there is a clearance (empty space) inside the bushing between the inner surface of the bushing and the outer surface of the portion of the drive shaft being inserted thereinto. Thus, the drive shaft can have some (limited) freedom of movement inside the bushing. That allows the drive shaft to move inside the bushing and to be adjusted therein.

The drive shaft can be adjusted, e.g., by being moved along its longitudinal axis, up and/or down, resulting in longitudinal tolerance compensation; by being moved laterally so that there is a distance formed between the longitudinal axis of the drive shaft and the longitudinal axis of the cap (and/or bushing), resulting in lateral tolerance compensation; and by causing the shaft to tilt (to be angled) relative to the longitudinal axis of the cap so that the longitudinal axis of the drive shaft is not parallel to the longitudinal axis of the cap, resulting in angular tolerance compensation. Of course, any combination of longitudinal tolerance compensation, lateral tolerance compensation, and angular tolerance compensation can have place, as needed. Such adjustment(s), if needed, can effectively remedy a potential or real misalignment exceeding the otherwise requisite tolerances among the parts being assembled, thereby effectively relaxing such strict tolerances. This would simplify and streamline the process of assembling the product, making the process more flexible and the product less expensive.

After the drive shaft has been adjusted inside the bushing to compensate for variation of a shapes and/or dimensions of a part being assembled, the tolerance-compensation element can be affixed to the drive shaft and to the bushing, e.g., by at least one of gluing and welding, e.g., laser-welding.

In one embodiment, the tolerance-compensation element comprises a disk-like structure having an outer diameter of from about 3 mm to about 12 mm and a through-hole having a diameter of from about 1 mm to about 6 mm. The tolerance-compensation element may have a thickness of from about 0.2 mm to about 2 mm.

The at least one first magnetic coupling clement may comprise at least one permanent magnet and/or at least one magnetizable element. The handle may beneficially include a magnet seal disposed in the cap between the first magnetic coupling element and the bushing.

In another aspect, the present disclosure is directed to a handle for a personal-care implement comprising the coupling section as is described herein.

In still another aspect, the present disclosure is directed to a process of making a handle for a personal-care implement, wherein the handle comprises a drive unit including a drive shaft. The process comprises the steps of: providing a cap comprising a tubular structure and having a first end and a second end opposite to the first end, the second end of the cap being an open end; inserting at least one first magnetic coupling clement into the cap so that the at least one first magnetic coupling element is disposed adjacent to the second end of the cap; providing a bushing having a first end and a second end opposite to the first end, the second end of the bushing being an open end; mounting a bushing inside the cap and adjacent to the second end of the cap so that the second end of the bushing is adjacent to the second end of the cap; providing a tolerance-compensation element having a through-hole sized to receive the drive shaft therethrough; arranging a tolerance-compensation element at the second end of the bushing; inserting a portion of the drive shaft, through the through-hole of the tolerance-compensation clement, into the bushing, wherein there is a clearance (empty space) between an inner surface of the bushing and an outer surface of a portion of the drive shaft inserted into the bushing so that the drive shaft has a freedom of movement inside the bushing; and affixing the tolerance-compensation element to the drive shaft and to the bushing.

The process may further include a steps of arranging a magnet seal in the cap and/or a step of pressing the tolerance-compensation element against the second end of the bushing. The step of fixing a bushing inside the cap may comprise mounting the bushing by press-fitting, crimping, shrink-fitting, gluing, welding, snapping, or any combination thereof. In one beneficial embodiment, the step of fixing a bushing in the cap further comprises laser-welding of the bushing to the tubular structure of the cap.

In one embodiment, the step of affixing the tolerance-compensation element to the drive shaft and to the bushing comprises laser-welding of the tolerance-compensation element to the second end of the bushing.

The process may further comprise a step of adjusting a position of the drive shaft inside the bushing prior to the step of affixing the tolerance-compensation element to the drive shaft and to the bushing. The step of adjusting a position of the drive shaft inside the bushing may include moving the drive shaft along its longitudinal axis (up or down), inclining the drive shaft relative to the longitudinal extension of the cap so that the longitudinal axis of the drive shaft is not parallel to the longitudinal axis of the cap, moving the drive shaft in a lateral direction (i.e., substantially perpendicular to the longitudinal axis of the drive shaft) so that the longitudinal axis of the drive shaft and the longitudinal axis of the cap do not coincide with one another and there is a distance between the two, and any combination thereof.

In another aspect, the disclosure is directed to a coupling section for coupling a handle of a personal-care implement and a replaceable attachment tool, wherein the coupling section comprises a bushing having a longitudinal axis and a first end and a second end opposite to the first end, a drive shaft having a longitudinal axis and a free end terminating in the bushing, the free end of the drive shaft being inserted into the bushing through the first end thereof, a first magnetic coupling clement mounted adjacent to the second end of the bushing, and an elastic magnet seal disposed between the first magnetic coupling element and the bushing, the magnet seal being structured and configured to flex in at least a direction along the longitudinal axis of the bushing, thereby providing at least longitudinal tolerance compensation for the drive shaft relative to the first magnetic coupling element.

DETAILED DESCRIPTION

The following description does not attempt to list every possible embodiment of the invention because that would be impractical if not impossible. This disclosure, therefore, is to be construed as containing representative examples or embodiments of the invention. That is, any feature, characteristic, structure, component, element, or step described herein can be combined with or substituted for, in whole or in part, any other suitable feature, characteristic, structure, component, element, or step described herein. It should also be understood that the relative scale of some elements shown in the drawings may not be exact, as the dimensions, including thickness/height, of the components exemplified in the several example embodiments may be exaggerated for the purposes of illustration.

An example embodiment of a personal-care implement10shown inFIGS.1-3is an electric toothbrush that comprises a handle300and a replaceable attachment tool200. The attachment tool200shown in this example embodiment is a brush head. As is known in the art, the replaceable attachment tool200comprises a housing having a head section including a head cavity for accommodating a movable oral-cleaning head220and a neck section210having a neck cavity therein inside, and a coupling section350, for coupling the replaceable attachment tool200to the handle300.

As is disclosed in commonly assigned U.S. Pat. Nos. 8,631,532, 9,226,808, and 9,387,059, the entire disclosures of which are incorporated herein by reference, a magnetic force between a first magnetic coupling element and a second magnetic coupling element (at least one of which could be a permanent magnet or a magnetizable element) can be used to form mechanical handle drive shaft connection to a replaceable attachment tool. One of the magnetic coupling elements may be arranged at the handle's drive shaft, and another inside the attachment tool.

As is shown inFIGS.1-3, the handle300of the personal-care implement10comprises a drive unit330including a drive shaft310that has a longitudinal axis L1and a free end311. A coupling section350includes components for coupling the replaceable attachment tool200(e.g., a brush head) to the handle300, as is known in the art. In the instance of an electric toothbrush (exemplified inFIG.1), the drive shaft310can have an operation frequency of from about 50 Hz to about 270 Hz. The coupling section350includes a first magnetic coupling element150mounted at the free end311of the drive shaft310for connection, by magnetic interaction, with the second magnetic coupling clement270(e.g., a metal cylinder) mounted at a motion transmitter that extends inside the neck cavity of the neck210to the head cavity of a replaceable attachment tool200that is arranged for a brushing movement, e.g., rotational oscillation. Magnetic force F existing between the first magnetic coupling element150and the second magnetic coupling element270is schematically shown inFIG.6.

The coupling section350may include a cap140having a longitudinal axis L2and comprising an essentially tubular structure. The cap140has a first (open) end141and a second end142opposite to the first end141(FIGS.4and7). The cap140had an inner diameter D7(FIGS.8,16A,17A,17B). The cap140houses inside the first magnetic coupling element150that is disposed adjacent to the second end142of the cap140.

The coupling section350may further include a bushing170having a first (open) end171and a second end172opposite to the first end171. The bushing170can be fixed inside the cap140, e.g., by press-fitting and/or laser welding, to be disposed adjacent to the first end141of the cap140so that the first end171of the bushing170is neighboring the first end141of the cap140(FIGS.10,11). As the bushing170is securely fixed inside the cap140so that a longitudinal extension of the bushing is substantially parallel to a longitudinal extension of the cap140, both the cap140and the bushing170share the longitudinal axis L2(FIG.10). The longitudinal axis L2, therefore, can be referred to as “the longitudinal axis L2of the bushing170” and/or “the longitudinal axis L2of the cap140” or “the longitudinal axis L2of (both) the bushing170and the cap140.”

As is best shown inFIGS.4and11, a tolerance-compensation element250can be arranged at the first end171of the bushing170. An embodiment of the tolerance-compensation element250illustrated herein has a through-hole255having a diameter D2(FIG.5), sized to receive the drive shaft310therethrough. The drive shaft310is inserted, through the tolerance-compensation element250, into the bushing170and is affixed to the tolerance compensation element250and to the bushing170.

The bushing170is sized to loosely receive the free end of the drive shaft310being inserted into the bushing170. The term “loosely” in the present context indicates that the outer diameter D3of the portion of the drive shaft310that is inserted into the bushing170is somewhat smaller than an inner diameter D4of the bushing170, so that there is a clearance, or empty space, between an inner surface of the bushing170and an outer surface of the portion of the drive shaft310inserted into the bushing170, which empty space allows the shaft310to move inside and relative to the bushing170. In other words, there is no “tight” fitting between the bushing170and the portion of the drive shaft310inserted into the bushing170. This clearance, or empty space, existing between the inner surface of the bushing170and the outer surface of the portion of the drive shaft310inserted into the bushing170allows the drive shaft310to have a freedom of movement inside the bushing170during assembly.

This freedom of movement of the drive shaft310inside the bushing170may include a freedom of movement in an axial direction (i.e., along the longitudinal axis L1of the drive shaft310), resulting in a longitudinal tolerance compensation; a freedom of movement in a lateral direction so that a distance “X” is formed between the longitudinal axis L1of the drive shaft310and the longitudinal axis L2of the cap140(FIG.12B), resulting in a lateral tolerance compensation; and a freedom of angular, or tilting, movement, causing the shaft310being slightly tilted, or inclined, relative to the longitudinal axis L2of the cap140so that the longitudinal axis L1of the drive shaft310is not parallel to the longitudinal axis L2of the cap140(FIG.12A), resulting in an angular tolerance compensation; and any combination of the above.

The freedom of movement of the drive shaft310inside the bushing170offers a manufacturer the ability to adjust, during assembly, the drive shaft310inside the bushing170, thereby compensating for minor variation in size and dimensions of the parts being assembled, which variation may exceed the otherwise requisite tolerances among those parts and/or the surrounding structures. Such adjustment during assembly may include, e.g., slightly inclining the drive shaft310relative to the longitudinal extensions of the cap140and/or the bushing170—which would result in a lack of perfect alignment between the longitudinal axis L1of the drive shaft310and the longitudinal axis L2of the cap140. In other words, in some embodiments, the drive shaft310may be inclined relative to the longitudinal extension of the cap140so that the longitudinal axis L1of the drive shaft310is not parallel to the longitudinal axis L2of the cap140, and there is an angle “A” formed between the longitudinal axis L1and the longitudinal axis L2, as is schematically shown inFIG.12A. Stated differently, the drive shaft310may have a position characterized by a degree of an angular deviation from an axial alignment with the longitudinal extensions of the cap140. The angle “A” can be from 0 degree to about 25 degree, and more specifically from 0 degree to about 15 degree, and even more specifically from 0degree to about 5 degree. In one embodiment, the angle “A” can be from about 0.2 degree to about 6 degree.

Such adjustment during assembly may also, alternatively or additionally, include moving the drive shaft310in the lateral direction relative to the longitudinal extensions of the cap140and/or the bushing170, so that a distance “X” is formed between the longitudinal axis L1of the drive shaft310and the longitudinal axis L2of the cap140and/or the bushing170(FIG.12B). That would result in the drive shaft310having a position characterized by a lateral deviation from an axial alignment with the longitudinal extensions of the cap140. The distance “X” can be from about 0.005 mm to about 1 mm, and more specifically from about 0.01 mm to about 0.5 mm. In one embodiment, the tolerance compensation in the lateral direction may result in a distance “X” from about 0.005 mm to about 0.15 mm formed between the longitudinal axis L1of the drive shaft310and the longitudinal axis L2of the bushing170.

Likewise, the drive shaft310can be moved/adjusted along its longitudinal axis L2, up and/or down the axis L2, resulting in a longitudinal tolerance compensation, as may be required during assembly. Of course, any of the tolerance-compensation adjustments described herein can be combined as needed. Thus, the drive shaft310may have a position characterized, e.g., by both a lateral deviation (lateral tolerance compensation) and an angular deviation (angular tolerance compensation) from the axial alignment with the longitudinal axis of the cap140. Such adjustment(s), when desirable, can be effectively implemented to compensate for a misalignment among the parts being assembled, which misalignment could be caused by variations in the parts' shapes and sizes exceeding the requisite tolerances, e.g., for the reasons previously mentioned.

The tolerance-compensation element250can be affixed to the drive shaft310and to the bushing170by any means known in the art, e.g., by gluing and/or welding. In one beneficial embodiment, the tolerance-compensation clement250is affixed to the drive shaft310and to the bushing170by laser-welding, e.g., at points250a,250b,250c,and250d,as is schematically illustrated inFIG.13. The number of fixation points (four inFIG.13) is for illustration purposes only—and any other suitable number of laser-welding points could be employed, if advisable, to fix the tolerance-compensation element250.

In the example embodiments illustrated inFIGS.5,5A, andFIG.5B, the tolerance-compensation clement250comprises substantially a disk structure, or annulus-full (FIG.5A) or partial (FIG.5B). Other suitable shapes of the tolerance-elimination element250, e.g., rectangular, polygonal, oval, and the like (not illustrated herein), are contemplated by the present disclosure. The tolerance-compensation element250may have an outer diameter (or the largest dimension measured through the geometric center of a non-round tolerance compensation element250) D1of from about 3 mm to about 12 mm. A through-hole of the tolerance-compensation clement250may have a diameter D2of from about 1 mm to about 6 mm. The through-hole may be centrally located, as is shown inFIGS.5,5A and5B. The tolerance-compensation clement250may have a thickness of from about 0.2 mm to about 2 mm.

The inner diameter D4of the bushing170can be from about 1.5 mm to about 10 mm. The outer diameter D3of the drive shaft310can be from about 1 mm to about 6 mm. In a specific arrangement to be assembled, the outer diameter D3of the drive shaft310may be slightly (0.5%-5%) smaller than the diameter D2of the through-hole of the tolerance-compensation element250. That would allow the drive shaft310to have some limited freedom of angular movement relative to the tolerance-compensation element250during assembly of the implement. In other words, the drive shaft310could be slightly inclined relative to the tolerance compensation clement250so that the longitudinal axis L1of the shaft310is not strictly perpendicular to the lateral extension of the tolerance-compensation element250.

The first magnetic coupling clement150may comprise at least one of a permanent magnet and a magnetizable clement, for providing magnetic connection with the corresponding second magnetic coupling element270(such as, e.g., a metal cylinder) arranged in a replaceable attachment tool200. As is shown inFIGS.3,4,6,9-13, and16A-16L, the handle300may beneficially include an elastic magnet seal160disposed in the cap140between the first magnetic coupling element150and the bushing170. The magnet seal may protect the first magnetic coupling element150from moisture. It may also help to have the first magnetic coupling element150adequately pressed against the inner side of the cap surface. As the magnet seal160is elastic, it can additionally function as a shock-absorbing element that would protect the personal-care implement against stress in case of a drop.

Furthermore, the magnet seal160may function as a flexible tolerance-compensation clement, in combination with, or independently from, the tolerance-compensation element250, previously described. As such, the magnet seal160can be structured and configured to flex to provide tolerance compensation for the drive shaft310in at least a longitudinal direction substantially parallel to the longitudinal axis L2of the bushing170.FIG.19illustrates an embodiment of the coupling section wherein the magnet seal160(shown in its non-compressed condition) functions as a tolerance-compensation element. As a result of tolerance compensation in the longitudinal direction, a distance S can be formed of formed between a free end of the drive shaft310and an inner surface of the bushing170facing the free end of the drive shaft310. The distance S can be from about 0.001 mm to about 4 mm, and more specifically from about 0.01 mm to about 3 mm.

The magnet seal160can also be structured and configured to flex to provide tolerance compensation for the drive shaft310in a lateral direction substantially perpendicular to the longitudinal axis L2of the bushing170, and/or an angular direction resulting in an angle being formed between the longitudinal axis L2of the bushing170and the longitudinal axis L1of the drive shaft310, as is previously described herein.

The magnet seal160may generally comprise a three-dimensional annular structure having any suitable shape. The seal160may be configured to flex in at least a direction along the longitudinal axis of the bushing170thereby providing at least longitudinal tolerance compensation for the drive shaft310relative to the first magnetic coupling element150. As is described above, the magnetic seal160may also be structured to provide a lateral tolerance compensation and/or an angular tolerance compensation.

Various non-limiting example embodiments of the magnet seal160are illustrated inFIGS.3,4,6,9-13,16A-16L,17A,17B,18A, and18B. The magnet seal160has an unconstrained outer diameter D5that is greater than the inner diameter D7of the cap140by at least 5 percent. The term “unconstrained” is used herein to define a given parameter/dimension (e.g., an outer diameter D5(FIGS.17A,17B, and18A) or an overall height K (FIG.18B)) of the seal160in non-compressed condition, prior to the seal160being inserted into the cap140and/or compressed by the surrounding elements. The seal160is designed to be compressed (or squeezed) inside the cap140by the walls of the cap140(FIGS.16K and16L), thereby providing requisite insulation. A compressed, or constrained, overall diameter of the seal160is therefore smaller than the unconstrained diameter D5. The seal160is also compressed between the magnet coupling clement150and the bushing170, resulting in a compressed, or constrained, height that is smaller than the unconstrained height K of the seal160.

The magnet seal160can have an unconstrained outer diameter D5of from about 3 mm to about 13 mm, and more specifically from about 5 mm to about 10 mm. A ratio of the unconstrained outer diameter D5of the magnet seal160to the inner diameter D7of the cap140(the constrained outer diameter of the seal140) can be from about 1.05 to about 1.25, and more specifically from about 1.1 to about 1.2. The magnet seal160can have an overall unconstrained height K (FIG.18B) of from about 1 mm to about 4 mm, and more specifically from about 1.5 mm to about 3 mm. A ratio of the unconstrained height K to the constrained thickness of the magnet seal140can be from about 1.05 to about 1.4, and more specifically from 1.1 to about 1.3. A ratio of the unconstrained outer diameter D5to the overall unconstrained height K of the magnet seal160can be from about 2 to about 5.

As is illustrated in the drawings herein, the magnet seal160may have at least one centrally located annular protrusion161outwardly extending from at least one side thereof and having an unconstrained outer diameter D6(FIG.18A). The at least one annular protrusion161extends generally parallel to the longitudinal axis of the cap140. The unconstrained outer diameter D6can be from about 2 mm to about 12 mm, and more specifically from about 4 mm to about 10 mm. At least a portion of a surface of the magnet seal160can be treated with non-stick coating comprising, e.g., fluorination, providing/facilitating a coefficient of friction below 0.2. The magnet seal160can be made of a rubber material having a Shore A Hardness of from 40 to 60. Non-limiting examples of the rubber material include silicone or NBR or EPDM.

FIGS.17A and17Bschematically illustrate relationship between the dimensions of the magnet seal160and the dimensions of the surrounding structures in the assembled coupling section350, in which figures the magnet seal160is shown, for illustrative purposes, in its non-compressed condition.FIG.17Aillustrates an example embodiment of the magnet seal140, wherein the unconstrained outer diameter D5of the magnet seal160is greater than the inner diameter D7of the cap140(by a double overlap “A”) and the unconstrained height of the magnet seal160is greater than the longitudinal dimension of the space inside the cap140(by a longitudinal overlap “B”) intended for containing the seal160when the coupling section350is fully assembled.FIG.17Billustrates another example embodiment of the magnet seal140, wherein the unconstrained outer diameter D5of the magnet seal160is greater than the inner diameter D7of the cap140(by a double overlap “C”) and the unconstrained height of the magnet seal160is greater than the longitudinal dimension of the space inside the cap140(by a longitudinal overlap “E”) intended for containing the seal160when the coupling section350is fully assembled.

In another aspect, the disclosure is directed to a coupling section350for coupling a handle300of a personal-care implement10and a replaceable attachment tool200. The coupling section350comprises a drive shaft310having a longitudinal axis L1and a free end311terminating in a bushing170having a first end171and a second end172opposite to the first end171. The free end311of the drive shaft310is inserted into the bushing170through the first end171of the bushing170. A first magnetic coupling element160is mounted adjacent to the second end172of the bushing.

A tolerance-compensation element250has a through-hole255sized to loosely receive the drive shaft310therethrough. The tolerance-compensation element250is mounted adjacent to the first end171of the bushing, and the free end311of the drive shaft310is disposed in the bushing170so that there is a space between an inner surface of the bushing170and an outer surface of the drive shaft310. The tolerance-compensation element250is affixed to the drive shaft310and to the bushing170—and at least partially encircles a portion of the drive shaft310adjacent to the first end171of the bushing170. An embodiment of the tolerance-compensation element250, having a shape of a partial annulus (somewhat resembling a general outline of a horseshoe), as is illustrated inFIG.5B, would partially encircle a portion of the drive shaft310adjacent to the first end171of the bushing170.

A process of making a handle300for a personal-care implement10comprises the steps of providing a cap140comprising a tubular structure and having a first end141and a second end142opposite to the first end141, the first end of the cap being an open end (FIG.7); inserting a first magnetic coupling element150into the cap140so that the first magnetic coupling element150is disposed adjacent to the second end142of the cap140(FIG.8); providing a bushing170having a first end171and a second end172opposite to the first end171, the first end171of the bushing170being an open end and mounting a bushing170inside the cap140and adjacent to the first end141of the cap so that the first end of the bushing171is adjacent to the first end141of the cap140(FIG.10); providing a tolerance-compensation element250having a through-hole255sized to receive the drive shaft310therethrough and arranging the tolerance-compensation element250at the first end171of the bushing170(FIG.11); inserting a portion of the drive shaft310, through the through-hole255of the tolerance-compensation element250, into the bushing170, wherein there is a clearance between an inner surface of the bushing170and an outer surface of the portion of the drive shaft310inserted into the bushing170so that the drive shaft310has a freedom of movement inside the bushing170(as previously described,FIGS.12,12A, and12B); and affixing the tolerance-compensation element250to the drive shaft310and to the bushing170(FIG.13).

In one embodiment, the process includes a step of arranging a magnet seal160in the cap140(FIG.9). The magnet seal160may be needed to protect the magnetic coupling element150from moisture and to press the magnetic coupling clement150against the inner side of the cap surface. As the seal160is clastic, it can also act as a shock-absorbing element and protection against stress if the implement is dropped or otherwise shaken or hits a hard surface.

In one embodiment, the process includes a step of pressing the tolerance-compensation element250against the first end171of the bushing170(FIGS.14,15) to facilitate fixation of the tolerance-compensation element to the bushing170. As is shown inFIGS.14and15, a down-holder tool, or clamp,400may be used to press and hold the tolerance-compensation element250against the first end171of the bushing170. The down-holder tool400may comprise, e.g., two mutually opposing (or more than two) prongs410,420structured and configured to contact the top of the tolerance-compensation clement250and apply a requisite pressure to hold the tolerance-compensation element260in place against the bushing170for affixing the tolerance-compensation element250to the first end171of the busing170and the drive shaft310. The down-holder tool400can be driven pneumatically, electrically, mechanically, hydraulically, or by any other means known in the art and suitable for this purpose.

The step of fixing the bushing170inside the cap140may comprise mounting the bushing170by press-fitting, crimping, shrink-fitting, gluing, welding, snapping, or any combination thereof. In one beneficial embodiment, schematically illustrated inFIG.10, the step of fixing the bushing170in the cap140may further comprise laser-welding of the bushing170to the tubular structure of the cap140, e.g., at areas175.

The process may further comprise a step of adjusting a position of the drive shaft310inside the bushing170prior to the step of affixing the tolerance-compensation element250to the drive shaft310and to the bushing170. In one embodiment, the step of adjusting a position of the drive shaft310inside the bushing170comprises positioning the drive shaft310inside the bushing170so that the longitudinal axis L1of the drive shaft310is not strictly parallel to the longitudinal axis L2of the cap140, as is illustrated inFIG.12A.

In another aspect, the disclosure is directed to a coupling section for coupling a handle of a personal-care implement and a replaceable attachment tool, wherein the coupling section comprises a bushing having a longitudinal axis and a first end and a second end opposite to the first end, a drive shaft having a longitudinal axis and a free end terminating in the bushing, the free end of the drive shaft being inserted into the bushing through the first end thereof, a first magnetic coupling clement mounted adjacent to the second end of the bushing, and an elastic magnet seal disposed between the first magnetic coupling element and the bushing, the magnet seal being structured and configured to flex in at least a direction along the longitudinal axis of the bushing, thereby providing at least longitudinal tolerance compensation for the drive shaft relative to the first magnetic coupling element.

The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value, unless otherwise specified. For example, a dimension disclosed as “10 mm” is intended to mean “about 10 mm.”

The disclosure of every document cited herein, including that of any cross-referenced or related patent or application, is incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.