Joints for personal care devices, including tolerance compensation, and their manufacturing process

Abstract

A coupling for connecting a personal care device handle to an interchangeable mounting tool includes a drive shaft having a free end terminating within a bushing, a first magnetic coupling element mounted adjacent to the bushing, and a tolerance compensation element mounted adjacent to the bushing having a through-hole sized to receive the drive shaft through it. The free end of the drive shaft is positioned within the bushing such that a space exists between the inner surface of the bushing and the outer surface of the portion of the drive shaft positioned within it, thereby allowing the position of the drive shaft to be adjusted within the bushing during assembly. The tolerance compensation element, at least partially surrounding the drive shaft, is fixed to the drive shaft and the bushing. A personal care device handle and a process for manufacturing the handle are also disclosed.

Description

[Technical Field]

[0001] The present disclosure relates to mass production of multi-component personal care appliances, such as personal care devices including electric toothbrushes. [Background Art]

[0002] Mass production of multi-component personal care appliances, such as toothbrush handles and other similar articles, is typically carried out by a multi-step process that often requires mass manufacturing of multi-component parts which are subsequently assembled into finished products. To function as designed, these multi-component parts must be uniform and have substantially the same size and shape, within acceptable tolerances. The required uniformity between parts required to be identical can be defined by the extent to which minute variations in corresponding shapes and sizes between such mass-produced identical parts can be tolerated. Concerns regarding uniformity are particularly significant when multi-component parts required to be identical are manufactured at multiple locations where manufacturing conditions, equipment, and suppliers of required materials may differ somewhat.

[0003] For example, substantially all plastic materials molded into required parts are heated and liquefied during the manufacturing process, then cooled and solidified, and typically shrink during cooling, a phenomenon commonly known as "molding shrinkage", whereby at least some of the physical dimensions of the resulting part are reduced from the ideal or nominal dimensions, thus potentially causing a lack of uniformity between these plastic components. Additionally, for metal parts, deformation caused by welding may occur during assembly of the required parts, which may affect the uniformity between the parts. At the same time, accurate positioning of the required parts is required to enable a reliably stable process of assembly into the finished product.

[0004] Therefore, variations from the ideal or nominal shape and size of parts assembled into a finished fixture must be within acceptable tolerances. As used herein, the term “tolerance” refers to an acceptable amount of variation in a specified shape and / or measurable dimension from the ideal / nominal shape of a part of the fixture being assembled. Since it is impossible to manufacture any article or part thereof whose shape and dimensions precisely match those of the exact nominal values, tolerances are typically assigned to parts for manufacturing purposes as boundaries for acceptable finish. Thus, there is an acceptable degree of variation / deviation from the exact nominal values ​​that is suitable for a particular machine, process, or part. Tolerances can be applied to any shape and dimension. A manufactured part with a shape and / or dimension exceeding the tolerance is unlikely to be a part usable for its intended purpose. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Sequential assembly processes require precise positioning of the parts being assembled. To achieve this, manufacturers must ensure that the size and shape of all elements, including the parts being manufactured / assembled, match each other with high precision, requiring strict tolerances. These strict tolerances are often difficult to achieve, especially in the context of mass production of components, which may take place in various locations and under different business and environmental conditions, as mentioned above.

[0006] Such mass production requires multiple tools, including molding tools and components typically installed on different machines and intended to produce identical parts. For example, in the manufacture of handles for personal care tools such as electric brushes, which are typically designed to accommodate multiple components (e.g., a drive unit including at least a portion of a motor, battery, electronics, and drive shaft, and having other structural and functional attributes), reliable uniformity and precision between different tool and machine parts are crucial for achieving and maintaining required tolerances. [Means for solving the problem]

[0007] This disclosure aims to address the problem of easing the tight tolerances required in multi-component personal care devices. This is achieved by providing a joint and handle for multi-component personal care devices, which includes a novel functional element, i.e., a tolerance compensation element, that enables manufacturers to significantly relax otherwise tight tolerances for specific parts and manufacturing processes while maintaining the necessary reliability and functionality of the parts being manufactured and assembled. Thus, this disclosure provides a novel joint and handle for mass-produced multi-component personal care devices, as well as a more reliable and stable process for manufacturing and assembling the parts required for such mass-produced multi-component personal care devices.

[0008] In one embodiment, the disclosure relates to a coupling for a personal care device. The coupling comprises a drive shaft having a longitudinal axis and a free end. The personal care device may have any preferred operating frequency. In one exemplary embodiment, the drive shaft may be configured to have an operating frequency of about 50 Hz to about 270 Hz. The coupling may include at least one first magnetic coupling element mounted adjacent to the free end of the drive shaft for connection by magnetic interaction with at least one second magnetic coupling element of an interchangeable attachment tool. In the context of oral care, such an interchangeable attachment tool may comprise a movable (e.g., vibrating, rotating, or oscillating) brush head.

[0009] In one exemplary embodiment, the coupling has a cap having a longitudinal axis L2 and a tubular structure. The cap has a first (open) end and a second end opposite to the first end. The cap may house at least a first magnetic coupling element disposed adjacent to the second end of the cap. The handle may further include a bushing having a first (open) end and a second end opposite to the first end. The bushing may be fixed to the inside of the cap adjacent to the first end of the cap, such that the first end of the bushing is adjacent to the first end of the cap.

[0010] A tolerance compensation element may be positioned at the first end of the bushing. The tolerance compensation element has a through hole sized to receive the drive shaft through it. The drive shaft is inserted into the bushing through the tolerance compensation element and secured to the drive shaft and bushing.

[0011] The bushing can be usefully sized to loosely accommodate a portion of the drive shaft within it, such that a gap (empty space) exists between the inner surface of the bushing and the outer surface of the portion of the drive shaft inserted into it. Therefore, the drive shaft can have a certain degree of (limited) freedom of motion within the bushing. This allows the drive shaft to move and adjust within the bushing.

[0012] The drive shaft can be adjusted, for example, by moving it up and down along its longitudinal axis, thereby providing longitudinal tolerance compensation; by moving it laterally so that there is a distance between the longitudinal axis of the drive shaft and the longitudinal axis of the cap (and / or bushing), thereby providing lateral tolerance compensation; and by tilting (angling) the shaft 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, thereby providing angular tolerance compensation. Of course, any combination of longitudinal, lateral, and angular tolerance compensation is possible as needed. If necessary, such adjustments can effectively improve potential or actual misalignments that exceed other required tolerances between the assembled parts, thereby effectively mitigating such tight tolerances. This simplifies and streamlines the product assembly process, makes the process more flexible, and makes the product less expensive.

[0013] After the drive shaft has been adjusted inside the bushing to compensate for variations in the shape and / or dimensions of the assembled parts, the tolerance compensation element may be fixed to the drive shaft and bushing by, for example, at least one of bonding and welding, for example, laser welding.

[0014] In one embodiment, the tolerance compensation element comprises a disc-shaped structure having an outer diameter of approximately 3 mm to approximately 12 mm and a through hole having a diameter of approximately 1 mm to approximately 6 mm. The tolerance compensation element may have a thickness of approximately 0.2 mm to approximately 2 mm.

[0015] At least one first magnetic coupling element may comprise at least one permanent magnet and / or at least one magnetizable element. The handle may, advantageously, include a magnetic seal disposed within a cap between the first magnetic coupling element and the bushing.

[0016] In another aspect, this disclosure relates to a handle for a personal care device having a coupling as described herein.

[0017] In yet another embodiment, the disclosure relates to a process for manufacturing a handle for a personal care device, the handle comprising a drive unit including a drive shaft. The process comprises the steps of: providing a cap comprising a tubular structure, 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 element into the cap so that at least one first magnetic coupling element is positioned 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; and positioning the bushing inside the cap and the second end of the cap so that the second end of the bushing is adjacent to the second end of the cap The process includes: attaching a tolerance compensation element adjacent to a part; providing a tolerance compensation element having a through hole sized to receive a drive shaft through it; positioning the tolerance compensation element at the second end of the bushing; inserting a portion of the drive shaft into the bushing through the through hole of the tolerance compensation element, wherein a gap (empty space) exists between the inner surface of the bushing and the outer surface of the portion of the drive shaft inserted into the bushing, so that the drive shaft has a degree of freedom of movement within the bushing; and fixing the tolerance compensation element to the drive shaft and the bushing.

[0018] This process may further include the steps of positioning a magnetic seal inside the cap and / or pressing a tolerance compensation element against the second end of the bushing. The step of securing the bushing inside the cap may include mounting the bushing by press-fitting, crimping, shrink-fitting, bonding, welding, snap-fitting, or any combination thereof. In one useful embodiment, the step of securing the bushing inside the cap further includes laser welding the bushing to the tubular structure of the cap.

[0019] In one embodiment, the step of fixing the tolerance compensation element to the drive shaft and bushing includes the step of laser welding the tolerance compensation element to the second end of the bushing.

[0020] The process may further include adjusting the position of the drive shaft inside the bushing prior to the step of fixing the tolerance compensation element to the drive shaft and bushing. The step of adjusting the position of the drive shaft inside the bushing may include moving the drive shaft along its longitudinal axis (up and down); tilting the drive shaft with respect to the longitudinal extension of the cap such that the longitudinal axis of the drive shaft is not parallel to the longitudinal axis of the cap; moving the drive shaft laterally (i.e., substantially perpendicular to the longitudinal axis of the drive shaft) such that the longitudinal axis of the drive shaft and the longitudinal axis of the cap do not coincide and there is a distance between them; and any combination thereof.

[0021] In another aspect, the present disclosure provides a coupling for coupling a handle of a personal care appliance and a replaceable attachment tool, the coupling comprising: a bushing having a longitudinal axis, a first end, and a second end opposite the first end; a drive shaft having a longitudinal axis and a free end terminating within the bushing, wherein the free end of the drive shaft is inserted into the bushing through the first end of the bushing; a first magnetic coupling element mounted adjacent the second end of the bushing; and an elastic magnetic seal disposed between the first magnetic coupling element and the bushing, wherein the magnetic seal is structured and configured to bend in at least one direction along the longitudinal axis of the bushing, thereby providing at least longitudinal tolerance compensation of the drive shaft relative to the first magnetic coupling element. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] While the specification concludes with claims that particularly point out and distinctly claim the subject matter regarded as the invention, various embodiments will be better understood from the following description taken in conjunction with the accompanying drawings. [Figure 1] It is a schematic front view of an embodiment of a personal care appliance comprising a handle and a replaceable / disposable brush head attached to the handle. [Figure 2] It is a schematic partial view of the embodiment of the handle and the head shown in Figure 1, wherein the head is detached from the handle. [Figure 3] It is a schematic partial cross-sectional view of an embodiment of a personal care appliance having a coupling, comprising a handle and a replaceable / disposable brush head attached to the handle. [Figure 4] It is a schematic view of an exploded portion of a coupling of a personal care appliance comprising a tolerance compensation element. [Figure 5] It is a schematic cross-sectional view of an embodiment of a tolerance compensation element. [Figure 5A] It is a schematic top plan view of the tolerance compensation element shown in Figure 5. [Figure 5B] It is a schematic plan view of a tolerance compensating element that partially surrounds a drive shaft. [Figure 6] It is a schematic view of an assembled portion of a coupling part of a personal care appliance provided with a tolerance compensating element. [Figure 7] It schematically represents one step in a process for producing a personal care appliance, and schematically shows a cross-sectional view of a cap. [Figure 8] It schematically represents one step in a process for producing a personal care appliance, and schematically shows a cross-sectional view of a cap and a magnet element inserted into the cap. [Figure 9] It schematically represents one step in a process for producing a personal care appliance, and schematically shows a cross-sectional view of a cap, a magnet element, and a magnetic seal. [Figure 10] It schematically represents one step in a process for producing a personal care appliance, and schematically shows a cross-sectional view of a cap, a magnet element, a magnetic seal, and a bushing. [Figure 11] It schematically represents one step in a process for producing a personal care appliance, and schematically shows a cross-sectional view of a cap, a magnet element, a magnetic seal, a bushing, and a tolerance compensating element. [Figure 12] It schematically represents one step in a process for producing a personal care appliance, and schematically shows a cross-sectional view of a cap, a magnet element, a magnetic seal, a bushing, a tolerance compensating element, and a drive shaft. [Figure 12A] It schematically shows that a gap between an inner surface of a bushing and an outer surface of a portion of a drive shaft inserted into the bushing allows the drive shaft to freely perform angular movement inside the bushing. [Figure 12B] It schematically shows that a gap between an inner surface of a bushing and an outer surface of a portion of a drive shaft inserted into the bushing allows the drive shaft to have a degree of freedom of lateral movement inside the bushing. [Figure 13]This diagram outlines one step in the process of manufacturing personal care devices, which includes laser welding tolerance compensation elements to bushings and drive shafts. [Figure 14] This is a perspective view of a part of a personal care device currently under development, schematically showing a down holder tool adjacent to but not in contact with a tolerance compensation element. [Figure 15] Figure 14 is a schematic perspective view of a portion of a personal care device, illustrating the down holder tool in contact with the tolerance compensation element. [Figure 16A] A schematic diagram shows a fragment of a coupling having various exemplary embodiments of a magnetic seal. [Figure 16B] A schematic diagram shows a fragment of a coupling having various exemplary embodiments of a magnetic seal. [Figure 16C] A schematic diagram shows a fragment of a coupling having various exemplary embodiments of a magnetic seal. [Figure 16D] A schematic diagram shows a fragment of a coupling having various exemplary embodiments of a magnetic seal. [Figure 16E] A schematic diagram shows a fragment of a coupling having various exemplary embodiments of a magnetic seal. [Figure 16F] A schematic diagram shows a fragment of a coupling having various exemplary embodiments of a magnetic seal. [Figure 16G] A schematic diagram shows a fragment of a coupling having various exemplary embodiments of a magnetic seal. [Figure 16H] A schematic diagram shows a fragment of a coupling having various exemplary embodiments of a magnetic seal. [Figure 16I] A schematic diagram shows a fragment of a coupling having various exemplary embodiments of a magnetic seal. [Figure 16J] A schematic diagram shows a fragment of a coupling having various exemplary embodiments of a magnetic seal. [Figure 16K] A schematic diagram shows a fragment of a coupling having various exemplary embodiments of a magnetic seal. [Figure 16L] A schematic diagram shows a fragment of a coupling having various exemplary embodiments of a magnetic seal. [Figure 17A]The relationship between the dimensions of an exemplary embodiment of the magnetic seal and the dimensions of the surrounding structure at the assembled joint is schematically illustrated, and the magnetic seal is shown in its uncompressed state for illustrative purposes. [Figure 17B] Similar to Figure 17A, another exemplary embodiment of the uncompressed / unrestrained magnetic seal in the assembled joint is schematically shown. [Figure 18A] A schematic side view of an exemplary embodiment of a magnetic seal is shown. [Figure 18B] A schematic cross-sectional view of an embodiment of the magnetic seal shown in Figure 18A is provided. [Figure 19] A schematic diagram of a fragment of a personal care device having a coupling in which a magnetic seal functions as a tolerance compensation element is shown. [Modes for carrying out the invention]

[0023] The following description is not intended to enumerate all possible embodiments of the present invention. Therefore, this disclosure should be interpreted as including representative examples or embodiments of the present invention. That is, any feature, characteristic, structure, component, element, or process described herein may be combined in whole or in part with, or substituted for, any other preferred feature, characteristic, structure, component, element, or process described herein. Furthermore, please understand that the relative scale of some elements shown in the drawings may not be accurate, as dimensions, including thickness / height, of components illustrated in some exemplary embodiments may be exaggerated for illustrative purposes.

[0024] An exemplary embodiment of the personal care device 10 shown in Figures 1 to 3 is an electric toothbrush comprising a handle 300 and a replaceable attachment tool 200. The attachment tool 200 shown in this exemplary embodiment is a brush head. As is known in the art, the replaceable attachment tool 200 comprises a housing having a head portion including a head cavity for housing a movable oral irrigation head 220, a neck portion 210 having a neck cavity inside the head, and a coupling portion 350 for coupling the replaceable attachment tool 200 to the handle 300.

[0025] As disclosed in U.S. Patents No. 8,631,532, No. 9,226,808, and No. 9,387,059 by the same applicant (their entire disclosures are incorporated herein by reference), a mechanical handle drive shaft connection to a replaceable mounting tool can be formed by using a magnetic force between a first magnetic coupling element and a second magnetic coupling element (at least one of which may be a permanent magnet or a magnetizable element). One of the magnetic coupling elements may be located on the handle drive shaft, and the other magnetic coupling element may be located inside the mounting tool.

[0026] As shown in Figures 1 to 3, the handle 300 of the personal care device 10 comprises a drive unit 330 including a drive shaft 310 having a longitudinal axis L1 and a free end 311. The coupling 350 includes components for coupling a replaceable attachment tool 200 (e.g., a brush head) to the handle 300, as is known in the art. In the case of an electric toothbrush (exemplified in Figure 1), the drive shaft 310 may have an operating frequency of about 50 Hz to about 270 Hz. The coupling 350 includes a first magnetic coupling element 150 attached to the free end 311 of the drive shaft 310, which is connected by magnetic interaction to a second magnetic coupling element 270 (e.g., a metal cylinder) attached to a motion transmission section that extends inside the neck cavity of the neck 210 to the head cavity of the replaceable attachment tool 200 configured for brushing motion, e.g., rotational vibration. The magnetic force F between the first magnetic coupling element 150 and the second magnetic coupling element 270 is schematically shown in Figure 6.

[0027] The coupling portion 350 may include a cap 140 having a longitudinal axis L2 and essentially a tubular structure. The cap 140 has a first (open) end 141 and a second end 142 opposite the first end 141 (Figures 4 and 7). The cap 140 has an inner diameter D7 (Figures 8, 16A, 17A, and 17B). The cap 140 houses a first magnetic coupling element 150 disposed adjacent to the second end 142 of the cap 140.

[0028] The joint 350 may further include a bushing 170 having a first (open) end 171 and a second end 172 opposite to the first end 171. The bushing 170 may be fixed inside the cap 140, for example by press-fitting and / or laser welding, and positioned adjacent to the first end 141 of the cap 140, so that the first end 171 of the bushing 170 is close to the first end 141 of the cap 140 (Figures 10 and 11). The bushing 170 is firmly fixed inside the cap 140 such that the longitudinal extension of the bushing is substantially parallel to the longitudinal extension of the cap 140, so that both the cap 140 and the bushing 170 share a longitudinal axis L2 (Figure 10). Therefore, the longitudinal axis L2 may be referred to as "the longitudinal axis L2 of the bushing 170" and / or "the longitudinal axis L2 of the cap 140" or "the longitudinal axis L2 of the bushing 170 and the cap 140 (both)".

[0029] As best shown in Figures 4 and 11, the tolerance compensation element 250 may be positioned at the first end 171 of the bushing 170. Embodiments of the tolerance compensation element 250 shown herein have a through hole 255 having a diameter D2 (Figure 5), the through hole being sized to receive the drive shaft 310 through it. The drive shaft 310 is inserted into the bushing 170 through the tolerance compensation element 250 and secured to the tolerance compensation element 250 and the bushing 170.

[0030] The bushing 170 is sized to loosely accommodate the free end of the drive shaft 310 that is inserted into the bushing 170. In this context, the term "loosely" means that the outer diameter D3 of the portion of the drive shaft 310 inserted into the bushing 170 is somewhat smaller than the inner diameter D4 of the bushing 170, thereby creating a gap or space between the inner surface of the bushing 170 and the outer surface of the portion of the drive shaft 310 inserted into the bushing 170, and this space allows the shaft 310 to move inside and relative to the bushing 170. In other words, there is no "tight" fit between the bushing 170 and the portion of the drive shaft 310 inserted into the bushing 170. This gap or space between the inner surface of the bushing 170 and the outer surface of the portion of the drive shaft 310 inserted into the bushing 170 allows the drive shaft 310 to have degrees of freedom of motion inside the bushing 170 during assembly.

[0031] The degrees of freedom of motion of the drive shaft 310 inside the bushing 170 include degrees of freedom of motion in the axial direction (i.e., along the longitudinal axis L1 of the drive shaft 310), thereby providing longitudinal tolerance compensation; degrees of freedom of motion in the lateral direction, thereby providing lateral tolerance compensation, such that a distance "X" is formed between the longitudinal axis L1 of the drive shaft 310 and the longitudinal axis L2 of the cap 140 (Figure 12B); degrees of freedom of angular or tilting motion, such that the longitudinal axis L1 of the drive shaft 310 is not parallel to the longitudinal axis L2 of the cap 140 (Figure 12A), thereby providing angular tolerance compensation; and any combination thereof.

[0032] The degree of freedom of motion of the drive shaft 310 inside the bushing 170 provides the manufacturer with the ability to adjust the drive shaft 310 inside the bushing 170 during assembly, thereby compensating for slight variations in the size and dimensions of the assembled parts, which may exceed the tolerances otherwise required between those parts and / or the surrounding structure. Such adjustments during assembly may include, for example, slightly inclining the drive shaft 310 with respect to the longitudinal extensions of the cap 140 and / or bushing 170, which results in a lack of perfect alignment between the longitudinal axis L1 of the drive shaft 310 and the longitudinal axis L2 of the cap 140. In other words, in some embodiments, the drive shaft 310 may be inclined with respect to the longitudinal extensions of the cap 140, so that the longitudinal axis L1 of the drive shaft 310 is not parallel to the longitudinal axis L2 of the cap 140, and an angle "A" is formed between the longitudinal axis L1 and the longitudinal axis L2, as schematically shown in Figure 12A. In other words, the drive shaft 310 may have a position characterized by the degree of angular deviation from axial alignment with the longitudinally extending portion of the cap 140. The angle "A" can be 0 degrees to about 25 degrees, more specifically 0 degrees to about 15 degrees, and even more specifically 0 degrees to about 5 degrees. In one embodiment, the angle "A" can be about 0.2 degrees to about 6 degrees.

[0033] Such adjustments during assembly may also, alternatively or additionally, involve moving the drive shaft 310 laterally relative to the longitudinal extensions of the cap 140 and / or bushing 170, thereby forming a distance "X" between the longitudinal axis L1 of the drive shaft 310 and the longitudinal axis L2 of the cap 140 and / or bushing 170 (Figure 12B). As a result, the drive shaft 310 has a position characterized by a lateral deviation from axial alignment with the longitudinal extension of the cap 140. The distance "X" may be about 0.005 mm to about 1 mm, more specifically about 0.01 mm to about 0.5 mm. In one embodiment, lateral tolerance compensation may result in a distance "X" of about 0.005 mm to about 0.15 mm formed between the longitudinal axis L1 of the drive shaft 310 and the longitudinal axis L2 of the bushing 170.

[0034] Similarly, the drive shaft 310 may be moved / adjusted along its longitudinal axis L2, above and / or below axis L2, to provide longitudinal tolerance compensation as may be required during assembly. Naturally, any of the tolerance compensation adjustments described herein can be combined as needed. Thus, the drive shaft 310 may have a position characterized 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 cap 140, for example. Such adjustments may be effectively implemented, if desired, for example, to compensate for misalignment between assembled parts that may be caused by variations in the shape and size of parts exceeding the required tolerances, for the reasons mentioned above.

[0035] The tolerance compensation element 250 can be fixed to the drive shaft 310 and bushing 170 by any means known in the art, for example, by bonding and / or welding. In one useful embodiment, the tolerance compensation element 250 is fixed to the drive shaft 310 and bushing 170 by laser welding at points 250a, 250b, 250c, and 250d, for example, as schematically shown in Figure 13. The number of fixing points (four in Figure 13) is for illustrative purposes only, and any other suitable number of laser welding points can be used to fix the tolerance compensation element 250, where appropriate.

[0036] In the exemplary embodiments shown in Figures 5, 5A, and 5B, the tolerance compensation element 250 includes a substantially disk structure or an entire ring (Figure 5A) or a portion (Figure 5B). Other preferred shapes of the tolerance removal element 250, such as rectangles, polygons, ellipses, etc. (not shown herein), are contemplated in this disclosure. The tolerance compensation element 250 may have an outer diameter D1 of about 3 mm to about 12 mm (or the maximum dimension measured through the geometric center of the non-circular tolerance compensation element 250). The through hole of the tolerance compensation element 250 may have a diameter D2 of about 1 mm to about 6 mm. The through hole may be centrally located, as shown in Figures 5, 5A, and 5B. The tolerance compensation element 250 may have a thickness of about 0.2 mm to about 2 mm.

[0037] The inner diameter D4 of the bushing 170 can be approximately 1.5 mm to 10 mm. The outer diameter D3 of the drive shaft 310 can be approximately 1 mm to 6 mm. In certain configurations to be assembled, the outer diameter D3 of the drive shaft 310 may be slightly smaller (0.5% to 5%) than the diameter D2 of the through hole in the tolerance compensation element 250. This allows the drive shaft 310 to have a certain degree of limited angular freedom relative to the tolerance compensation element 250 during the assembly of the fixture. In other words, the drive shaft 310 may be slightly inclined relative to the tolerance compensation element 250, so that the longitudinal axis L1 of the shaft 310 is not strictly perpendicular to the lateral extension of the tolerance compensation element 250.

[0038] The first magnetic coupling element 150 may comprise at least one of a permanent magnet and a magnetizable element to provide a magnetic connection with a corresponding second magnetic coupling element 270 (e.g., a metal cylinder) located within a replaceable mounting tool 200. As shown in Figures 3, 4, 6, 9-13, and 16A-16L, the handle 300 may also, beneficially, include an elastic magnetic seal 160 located within the cap 140 between the first magnetic coupling element 150 and the bushing 170. The magnetic seal may protect the first magnetic coupling element 150 from moisture. It may also help to properly press the first magnetic coupling element 150 against the inside of the cap surface. Because the magnetic seal 160 is elastic, it can further function as a shock absorber to protect the personal care device from stress in the event of a fall.

[0039] Furthermore, the magnetic seal 160 may function as a flexible tolerance compensation element, either in combination with or independently of the aforementioned tolerance compensation element 250. Therefore, the magnetic seal 160 may be structured and configured to bend to provide tolerance compensation for the drive shaft 310, at least in the longitudinal direction substantially parallel to the longitudinal axis L2 of the bushing 170. Figure 19 shows one embodiment of the joint in which the magnetic seal 160 (shown in its uncompressed state) functions as a tolerance compensation element. As a result of longitudinal tolerance compensation, a distance S may be formed between the free end of the drive shaft 310 and the inner surface of the bushing 170 facing the free end of the drive shaft 310. The distance S may be about 0.001 mm to about 4 mm, more specifically about 0.01 mm to about 3 mm.

[0040] The magnetic seal 160 may also be structured and configured to bend in a lateral direction substantially perpendicular to the longitudinal axis L2 of the bushing 170, and / or in an angular direction resulting in an angle formed between the longitudinal axis L2 of the bushing 170 and the longitudinal axis L1 of the drive shaft 310, as described above herein, in order to provide tolerance compensation for the drive shaft 310.

[0041] The magnetic seal 160 may generally comprise a three-dimensional annular structure having any suitable shape. The seal 160 may be configured to bend at least along the longitudinal axis of the bushing 170, thereby providing tolerance compensation of the drive shaft 310 to the first magnetic coupling element 150, at least in the longitudinal direction. As described above, the magnetic seal 160 may also be structured to provide lateral tolerance compensation and / or angular tolerance compensation.

[0042] Various non-limiting exemplary embodiments of the magnetic seal 160 are shown in Figures 3, 4, 6, 9–13, 16A–16L, 17A, 17B, 18A, and 18B. The magnetic seal 160 has an unrestricted outer diameter D5 that is at least 5 percent larger than the inner diameter D7 of the cap 140. The term “unrestricted” is used herein to define a given parameter / dimension of the seal 160 in an uncompressed state (e.g., outer diameter D5 (Figures 17A, 17B, and 18A) or total height K (Figure 18B)) before the seal 160 is inserted into the cap 140 and / or compressed by surrounding elements. The seal 160 is designed to be compressed (or pressed) inside the cap 140 by the walls of the cap 140 (Figures 16K and 16L), thereby providing the required insulation. Therefore, the compressed or constrained overall diameter of the seal 160 is smaller than the unconstrained diameter D5. The seal 160 is also compressed between the magnetic coupling element 150 and the bushing 170, resulting in a compression or constrained height smaller than the unconstrained height K of the seal 160.

[0043] The magnetic seal 160 can have an unconstrained outer diameter D5 of approximately 3 mm to approximately 13 mm, more specifically approximately 5 mm to approximately 10 mm. The ratio of the unconstrained outer diameter D5 of the magnetic seal 140 to the inner diameter D7 of the cap 140 (the constrained outer diameter of the seal 160) may be approximately 1.05 to approximately 1.25, more specifically approximately 1.1 to approximately 1.2. The magnetic seal 160 can have an overall unconstrained height K (Figure 18B) of approximately 1 mm to approximately 4 mm, more specifically approximately 1.5 mm to approximately 3 mm. The ratio of the unconstrained height K to the constrained thickness of the magnetic seal 140 may be approximately 1.05 to approximately 1.4, more specifically 1.1 to approximately 1.3. The ratio of the unconstrained outer diameter D5 of the magnetic seal 160 to the unconstrained total height K may be approximately 2 to approximately 5.

[0044] As shown in the drawings herein, the magnetic seal 160 may have at least one centrally located annular projection 161 extending outward from at least one of its sides and having an unrestrained outer diameter D6 (Figure 18A). The at least one annular projection 161 generally extends parallel to the longitudinal axis of the cap 140. The unrestrained outer diameter D6 may be about 2 mm to about 12 mm, more specifically about 4 mm to about 10 mm. At least a portion of the surface of the magnetic seal 160 may be treated with a non-stick coating, including, for example, fluorination, to provide / enhance a coefficient of friction of less than 0.2. The magnetic seal 160 may be made from a rubber material having a Shore A hardness of 40 to 60. Non-limiting examples of rubber materials include silicone, NBR, or EPDM.

[0045] Figures 17A and 17B schematically illustrate the relationship between the dimensions of the magnetic seal 160 and the dimensions of the surrounding structure within the assembled coupling 350, where the magnetic seal 160 is shown in its uncompressed state for illustrative purposes. Figure 17A shows an exemplary embodiment of the magnetic seal 140, where the unrestrained outer diameter D5 of the magnetic seal 160 is greater than the inner diameter D7 of the cap 140 (by double overlap "A"), and the unrestrained height of the magnetic seal 160 is greater than the longitudinal dimension of the space inside the cap 140 intended to accommodate the seal 160 when the coupling 350 is fully assembled (by longitudinal overlap "B"). Figure 17B shows another exemplary embodiment of the magnetic seal 140, where the unrestrained outer diameter D5 of the magnetic seal 160 is greater than the inner diameter D7 of the cap 140 (by double overlap "C"), and the unrestrained height of the magnetic seal 160 is greater than the longitudinal dimension of the inner space of the cap 140 intended to accommodate the seal 160 when the coupling 350 is fully assembled (by longitudinal overlap "E").

[0046] In another embodiment, the disclosure relates to a coupling 350 for connecting a handle 300 of a personal care device 10 to a replaceable mounting tool 200. The coupling 350 comprises a drive shaft 310 having a longitudinal axis L1 and a free end 311 terminating in a bushing 170 having a first end 171 and a second end 172 opposite to the first end 171. The free end 311 of the drive shaft 310 is inserted into the bushing 170 through the first end 171 of the bushing 170. A first magnetic coupling element 160 is mounted adjacent to the second end 172 of the bushing.

[0047] The tolerance compensation element 250 has a through hole 255, which is sized to loosely receive the drive shaft 310 through it. The tolerance compensation element 250 is mounted adjacent to the first end 171 of the bushing, and the free end 311 of the drive shaft 310 is positioned within the bushing 170 such that there is a space between the inner surface of the bushing 170 and the outer surface of the drive shaft 310. The tolerance compensation element 250 is fixed to the drive shaft 310 and the bushing 170 and at least partially surrounds the portion of the drive shaft 310 adjacent to the first end 171 of the bushing 170. As shown in Figure 5B, an embodiment of the tolerance compensation element 250 having a partial ring shape (somewhat resembling the overall contour of a horseshoe) partially surrounds the portion of the drive shaft 310 adjacent to the first end 171 of the bushing 170.

[0048] The process for manufacturing a handle 300 for a personal care device 10 includes the steps of: providing a cap 140 having a tubular structure and having a first end 141 and a second end 142 opposite to the first end 141, wherein the first end of the cap is an open end (Figure 7); inserting a first magnetic coupling element 150 into the cap 140 so that the first magnetic coupling element 150 is positioned adjacent to the second end 142 of the cap 140 (Figure 8); and providing a bushing 170 having a first end 171 and a second end 172 opposite to the first end 171, wherein the first end 171 of the bushing 170 is an open end, and mounting the bushing 170 inside the cap 140 adjacent to the first end 141 of the cap, thereby the first end 171 of the bushing being positioned adjacent to the cap The process includes: a step (Figure 10) adjacent to the first end 141 of the bushing 140, providing a tolerance compensation element 250 having a through hole 255 sized to receive the drive shaft 310 through it, and positioning the tolerance compensation element 250 on the first end 171 of the bushing 170 (Figure 11); a step (as described above, Figures 12, 12A, and 12B) in which a portion of the drive shaft 310 is inserted into the bushing 170 through the through hole 255 of the tolerance compensation element 250, wherein a gap exists between the inner surface of the bushing 170 and the outer surface of the portion of the drive shaft 310 inserted into the bushing 170, thereby allowing the drive shaft 310 to have degrees of freedom of motion inside the bushing 170; and a step (Figure 13) fixing the tolerance compensation element 250 to the drive shaft 310 and the bushing 170.

[0049] In one embodiment, the process includes the step of placing a magnetic seal 160 inside the cap 140 (Figure 9). The magnetic seal 160 may be required to protect the magnetic coupling element 150 from moisture and to press the magnetic coupling element 150 against the inside of the cap surface. Since the seal 160 is elastic, it can also function as a shock absorber and protect from stress if the instrument is dropped, shaken in other ways, or struck against a hard surface.

[0050] In one embodiment, the process includes pressing the tolerance compensation element 250 against the first end 171 of the bushing 170 (Figures 14 and 15) to facilitate the fixation of the tolerance compensation element to the bushing 170. As shown in Figures 14 and 15, a downholder tool or clamp 400 can be used to press and hold the tolerance compensation element 250 against the first end 171 of the bushing 170. The downholder tool 400 may comprise, for example, two opposing (or three or more) projections 410, 420 that are structured and configured to contact the top of the tolerance compensation element 250, hold the tolerance compensation element 260 in place against the bushing 170, and apply the necessary pressure to fix the tolerance compensation element 250 to the first end 171 of the bushing 170 and the drive shaft 310. The down holder tool 400 can be driven by pneumatic, electric, mechanical, hydraulic, or any other means known in the art and suitable for this purpose.

[0051] The step of securing the bushing 170 inside the cap 140 may include the step of mounting the bushing 170 by press-fitting, crimping, shrink-fitting, bonding, welding, snap-fitting, or any combination thereof. In one useful embodiment schematically shown in Figure 10, the step of securing the bushing 170 inside the cap 140 may further include, for example, laser welding the bushing 170 to the tubular structure of the cap 140 in region 175.

[0052] The process may further include a step of adjusting the position of the drive shaft 310 inside the bushing 170 prior to the step of fixing the tolerance compensation element 250 to the drive shaft 310 and the bushing 170. In one embodiment, the step of adjusting the position of the drive shaft 310 inside the bushing 170 includes a step of positioning the drive shaft 310 inside the bushing 170 so that the longitudinal axis L1 of the drive shaft 310 is not strictly parallel to the longitudinal axis L2 of the cap 140, as shown in Figure 12A.

[0053] In another embodiment, the present disclosure relates to a coupling for connecting a handle of a personal care device to an interchangeable mounting tool, the coupling comprising: 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 within the bushing, the free end of which is inserted into the bushing through the first end of the bushing; a first magnetic coupling element mounted adjacent to the second end of the bushing; and an elastic magnetic seal disposed between the first magnetic coupling element and the bushing, the magnetic seal being structured and configured to bend in at least one direction along the longitudinal axis of the bushing, thereby providing at least longitudinal tolerance compensation for the drive shaft with respect to the first magnetic coupling element.

[0054] The dimensions and values ​​disclosed herein should not be understood as being strictly limited to the exact numerical values ​​listed. Instead, unless otherwise specified, each such dimension is intended to mean both the listed value and the functionally equivalent range encompassing that value. For example, a dimension disclosed as "10 mm" is intended to mean "approximately 10 mm."

[0055] All disclosures of documents cited herein, including any cross-references or related patents or applications, are incorporated herein by reference in their entirety unless expressly excluded or otherwise limited. No citation of any document shall be deemed prior art to any invention disclosed or claimed herein, nor shall any such invention be taught, suggested, or disclosed, either alone or in combination with any one or more other references. Furthermore, 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 any document incorporated by reference, the meaning or definition given to that term in this document shall prevail.

[0056] While specific embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, it is intended that all such changes and modifications within the scope of the invention be covered in the appended claims.

Claims

1. A coupling for connecting the handle of a personal care device to a replaceable mounting tool, wherein the coupling is A bushing having a longitudinal axis, a first end, and a second end opposite to the first end, A drive shaft having a longitudinal axis and a free end terminating within the bushing, wherein the free end of the drive shaft is inserted into the bushing through the first end of the bushing, and in particular, the drive shaft is configured to have an operating frequency in the range of 50 Hz to 270 Hz. A first magnetic coupling element is attached adjacent to the second end of the bushing, A tolerance compensation element having a through hole sized to receive the drive shaft through it, wherein the tolerance compensation element is mounted adjacent to the first end of the bushing, and in particular the tolerance compensation element has a thickness in the range of 0.2 mm to 2.0 mm, The free end of the drive shaft is disposed within the bushing such that a space exists between the inner surface of the bushing and the outer surface of the free end of the drive shaft, and the tolerance compensation element at least partially surrounds a portion of the drive shaft in the region adjacent to the first end of the bushing. A coupling portion to which the tolerance compensation element is fixed to the drive shaft and the bushing.

2. The coupling according to claim 1, wherein the tolerance compensation element is fixed to at least one of the drive shaft and the bushing by at least one of bonding and welding, or the tolerance compensation element is fixed to at least one of the drive shaft and the bushing by laser welding.

3. The coupling part according to claim 1 or 2, wherein the tolerance compensation element comprises a disk having an outer diameter in the range of 3.0 mm to 12.0 mm and a through hole having a diameter in the range of 1.0 mm to 6.0 mm.

4. The coupling portion according to any one of claims 1 to 3, further comprising a magnetic seal disposed between the first magnetic coupling element and the bushing.

5. The coupling according to any one of claims 1 to 4, wherein the first magnetic coupling element is selected from at least one permanent magnet, at least one magnetizable element, or a combination thereof.

6. The coupling according to any one of claims 1 to 5, wherein the longitudinal axis of the drive shaft and the longitudinal axis of the bushing are not parallel to each other, and in particular, the angle formed between the longitudinal axis of the drive shaft and the longitudinal axis of the bushing is in the range of 0 to 25 degrees.

7. The coupling according to any one of claims 1 to 6, wherein the longitudinal axis of the drive shaft and the longitudinal axis of the bushing are separated by a distance, and in particular, the distance between the longitudinal axis of the drive shaft and the longitudinal axis of the bushing is in the range of 0.005 mm to 1.0 mm.

8. A handle for a personal care device, wherein the handle is A cap generally having a tubular structure, wherein the cap has a longitudinal axis, a first end, and a second end opposite to the first end, and the first end of the cap is an open end, A drive shaft having a longitudinal axis and a free end terminating inside the cap, A first magnetic coupling element is housed within the cap and disposed adjacent to the second end of the cap, A bushing having a first end and a second end opposite to the first end, wherein the first end of the bushing is an open end, and the bushing is mounted inside the cap and 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 having a through hole sized to receive the drive shaft through it, wherein the tolerance compensation element is attached to the first end of the bushing so as to at least partially surround the drive shaft, A portion of the drive shaft is disposed inside the bushing, The bushing and the portion of the drive shaft disposed therein are sized such that there is a space between the inner surface of the bushing and the outer surface of the portion of the drive shaft disposed therein, A handle in which the tolerance compensation element is fixed to the drive shaft and the bushing.

9. A process for manufacturing a handle for a personal care device, wherein the handle comprises a drive unit including a drive shaft having a longitudinal axis, and the process comprises, A step of providing a cap having a longitudinal axis and a tubular structure, wherein the cap has a first end and a second end opposite to the first end, and the first end of the cap is an open end. A step of inserting a first magnetic coupling element into the cap so that the first magnetic coupling element is positioned adjacent to the second end of the cap, A step of providing a bushing having a first end and a second end opposite to the first end, wherein the first end of the bushing is an open end. A step of attaching a bushing inside the cap and adjacent to the first end of the cap, wherein the first end of the bushing is adjacent to the first end of the cap, and the bushing is structured and configured to receive the free end of the drive shaft, A step of providing a tolerance compensation element having a disc-shaped structure with a through hole sized to receive the drive shaft through it, wherein the tolerance compensation element has a thickness in the range of 0.2 mm to 2.0 mm. A step of placing the tolerance compensation element at the first end of the bushing, A step of inserting a portion of the drive shaft into the bushing through the through hole of the tolerance compensation element, such that the free end of the drive shaft is disposed within the bushing, wherein a space exists between the inner surface of the bushing and the outer surface of the portion of the drive shaft inserted into the bushing, such that the drive shaft has a degree of freedom of motion inside the bushing. A process comprising the step of fixing the tolerance compensation element to the drive shaft and the bushing.

10. The process according to claim 9, wherein the degrees of freedom of motion of the drive shaft inside the bushing are selected from the degrees of freedom of motion of the drive shaft along its longitudinal axis, the degrees of freedom of motion the cap, and any combination thereof.

11. The process according to claim 9 or 10, further comprising the steps of arranging a magnetic seal between the bushing and the first magnetic coupling element, and / or pressing the tolerance compensation element against the first end of the bushing.

12. The process according to any one of claims 9 to 11, wherein the step of securing the bushing includes attaching the bushing to the inside of the cap by press-fitting, crimping, shrink-fitting, bonding, welding, snap-fitting, or any combination thereof, in particular the step of securing the bushing further includes laser welding the bushing to the cap, and / or the step of securing the tolerance compensation element includes laser welding the tolerance compensation element to the second end of the bushing, and / or the step of providing the tolerance compensation element includes providing the disc-shaped structure having an outer diameter in the range of 3.0 mm to 12.0 mm and the through hole having a diameter in the range of 1.0 mm to 6.0 mm.

13. The process according to any one of claims 9 to 12, wherein the step of adjusting the position of the drive shaft inside the bushing, prior to the step of fixing the tolerance compensation element, is selected from the group consisting of: moving the drive shaft axially along the longitudinal axis of the drive shaft; moving the drive shaft laterally substantially perpendicular to the longitudinal axis of the drive shaft to create a distance between the longitudinal axis of the drive shaft and the longitudinal axis of the cap; tilting the drive shaft with respect to the longitudinal axis of the cap such that the longitudinal axis of the drive shaft is not parallel to the longitudinal axis of the cap; and any combination thereof.

14. A coupling for connecting the handle of a personal care device to a replaceable mounting tool, wherein the coupling is A bushing having a longitudinal axis, a first end, and a second end opposite to the first end, A drive shaft having a longitudinal axis and a free end terminating within the bushing, wherein the free end of the drive shaft is inserted into the bushing through the first end of the bushing, A first magnetic coupling element is attached adjacent to the second end of the bushing, A coupling comprising: an elastic magnetic seal disposed between the first magnetic coupling element and the bushing, wherein the magnetic seal is structured and configured to bend, thereby providing tolerance compensation for the drive shaft in at least one direction selected from a longitudinal direction substantially parallel to the longitudinal axis of the bushing, a transverse direction substantially perpendicular to the longitudinal axis of the bushing, and an angular direction in which an angle is formed between the longitudinal axis of the bushing and the longitudinal axis of the drive shaft.

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