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Title:
LINEAR MOTOR AND ITS SUPPORT
Document Type and Number:
WIPO Patent Application WO/2016/103120
Kind Code:
A1
Abstract:
The present invention relates to an electric appliance for personal care like an electric shaver comprising a magnetic linear drive unit (5) having first (6) and second (7) drive components being supported for linear displacement relative to each other and being adapted to interact magnetically with each other, wherein the drive unit (5) is supported by a drive support (17) inside a mounting structure (16). The drive support (17), supporting the drive unit (5) on the mounting structure (16) of the installation environment, is adapted to pivot around at least one axis of rotation (22) and whereby allowing the first or second drive component (6, 7) of the drive unit (5) to rock inside said mounting structure (16).

Inventors:
KRAUS, Bernhard (Frankfurter Strasse 145, Kronberg, 61476, DE)
RING, Martin (Amselweg 32, Glashuetten, 61479, DE)
SCHAEFER, Robert (Frankfurter Strasse 145, Kronberg, 61476, DE)
Application Number:
IB2015/059694
Publication Date:
June 30, 2016
Filing Date:
December 16, 2015
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
BRAUN GMBH (Frankfurter Strasse 145, Kronberg, 61476, DE)
International Classes:
H02K33/12; B26B19/28; H02K5/16
Domestic Patent References:
WO2008009322A12008-01-24
WO2003103905A12003-12-18
WO2003103905A12003-12-18
Foreign References:
EP1515420A12005-03-16
DE10242094A12004-04-01
JPS5924226U1984-02-15
US3295808A1967-01-03
US20090025229A12009-01-29
US7841090B22010-11-30
EP0674979A11995-10-04
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Claims:
CLAIMS

1. An electric appliance for personal care, in particular electric shaver, comprising a magnetic linear drive unit (5) having first and second drive components (6, 7) supported for linear oscillation relative to each other and adapted to magnetically interact with each other, wherein a drive support (17) is provided for supporting the drive unit (5) onto a mounting structure (16), characterized in that said drive support (17) provides for at least one axis of rotation (22) for at least one of the drive components (6 and7) of the drive unit (5) allowing said at least one drive component (6, 7) to rotate relative to the mounting structure (16).

2. Electric appliance according to the preceding claim, wherein said drive support (17) includes a damper for dampening movements of the drive unit (5) and/or said at least one of the drive components (6, 7) about said at least one axis of rotation (22).

3. Electric appliance according to anyone of the preceding claims, wherein said drive support (17) includes at least one elastic restoring element (24) for elastically restoring the drive unit (5) into a rotatory home position about said at least one axis of rotation (22).

4. Electric appliance according to anyone of the preceding claims, wherein said drive support includes a pair of spring elements (19) supporting said drive unit (5) relative to said mounting structure (16), said pair of spring elements (19) defining a four point joint supporting said drive unit (5) rotatable about said at least one axis of rotation (22), wherein said four point joint includes two connection points fixed with the mounting structure (16) and two connection points fixed with the drive unit (5).

5. Electric appliance according to the preceding claim, wherein said pair of spring elements includes leaf springs (19) on opposite sides of the drive unit (5) arranged at an obtuse angle relative to each other and/or arranged to define, with their longitudinal axes (20), a virtual intersection point (21) in a center region of the drive unit (5).

6. Electric appliance according to anyone of the preceding claims, wherein the drive support (17) is adapted to define the said at least one axis of rotation (22) to be substantially coaxial with a center of rotational vibrations of the drive components (6, 7) oscillating relative to each other and/or substantial coaxial with a center of geometrical, polar inertia of said drive unit (5).

7. Electric appliance according to anyone of the preceding claims, wherein the drive support (17) is adapted to provide for said at least one axis of rotation (22) extending transverse to the oscillation axis (9) of the drive unit (5) and/or transverse to a longitudinal axis (25) of a handpiece of the electric appliance.

8. Electric appliance according to anyone of the preceding claims, wherein said first and second drive components (6, 7) are both supported movably relative to said mounting structure (16) and/or an installation environment, wherein each of said first and second drive components (6, 7) is supported pivotable about said at least one axis of rotation (22) provided by the drive support (17) and linearly displaceable along said oscillation axis (9) of the drive unit (5).

9. Electric appliance according to anyone of the preceding claims, wherein said first and second drive components (6, 7) are connected to each other by means of a pendulum bearing (14) or a four point bearing allowing for linear oscillation of said first and second drive components (6, 7) relative to each other.

10. Electric appliance according to the preceding claim, wherein said drive support (17) connects one of said first and second drive components (6, 7) and/or said pendulum bearing (14) to the mounting structure (16).

Description:
LINEAR MOTOR AND ITS SUPPORT

FIELD OF THE INVENTION

The present invention relates to electric appliances for personal care, in particular electric shavers, comprising a magnetic linear drive unit having first and second drive components supported for linear displacement relative to each other and adapted to magnetically interact with each other, wherein a drive support is provided for supporting the drive unit onto a mounting structure.

BACKGROUND OF THE INVENTION

Small sized electric appliances for personal care often include functional elements or working tools driven by an electric-type, more particularly magnetic-type drive unit which may be received within a housing element that may form a handpiece to be handheld.

For example, electric shavers may have one or more cutter elements driven by an electric drive unit in an oscillating manner where the cutter elements reciprocate under a shear foil, wherein such cutter elements or undercutters may have an elongated shape and may reciprocate along their longitudinal axis. Other types of electric shavers use rotatory cutter elements which may be driven in an oscillating or a continuous manner. The said electric drive may include an electric motor or a magnetic type linear motor, wherein the drive unit may include an elongated drive transmitter for transmitting the driving motion of the motor to the cutter element. Such drive systems include sometimes linear-type drive units comprising first and second drive components reciprocating or oscillating relative to each other in a substantially linear manner, i.e. substantially along linear axes, wherein the driving forces may result from magnetic fields. For example, one of the drive components may include a permanent magnet, whereas another one of the drive components may include one or more magnetic coils to which pulsating electric current is applied to create pulsating magnetic fields, thereby causing the two drive components to oscillate relative to each other. One of the drive components connects to a transmission train transmitting the oscillating movement of the drive component onto the functional element to be driven such as the aforementioned cutter element, wherein such transmission train may include a transmitter pin directly connecting to the cutter element or indirectly connected thereto by means of a yielding bridge structure allowing for pivoting movements of the cutter element.

For example, US 2009/0025229 Al or US 7,841,090 B2 discloses an electric shaver having a pair of cutter elements provided under a shear foil and driven in an oscillating manner.

Furthermore, WO 03/103905 Al and EP 0 674 979 Al disclose linear oscillating drive units for shavers, wherein the drive components oscillating relative to each other in a linear manner include a permanent magnet on the one hand and a magnetic coil on the other hand.

In such systems, one of the drive components may be rigidly connected to the mounting structure or the installation environment which is often a handpiece formed by a housing part of the electric appliance in which the drive unit is received. For example, the permanent magnet may be rigidly supported or fixedly connected to an interior side of the handpiece or a mounting structure connected thereto, whereas the other drive component including the magnetic coils may be movably supported for allowing the linear oscillation, for example by means of a pendulum bearing. Due to the fixed connection of one of the drive components to the handpiece, undesired vibrations can be implied onto the handpiece, thereby reducing the handling comfort. So as to reduce such undesired vibrations onto the handpiece, it already has been suggested to allow both drive components to execute linear oscillation in a counteracting manner. For example, WO 03/103905 Al suggests to not fix one of the drive components, but to fix the linkage or pendulum bars linking the two drive components to each other, to the installation environment in terms of an inner portion of the handpiece housing. Such fixing of the pendulum bearing to the mounting structure allows both drive units to oscillate in the direction of the oscillation axis in a sort of reverse motion. When a first drive component moves to the left, the other drive component moves to the right, and vice versa. Such reverse oscillation may reduce the aforementioned undesired vibrations of the handpiece. However, due to tolerances of the drive components and/or phase offset of the pulsating current, there still may be mismatch of the dynamic effects of the reverse motions and thus, vibrations that can be felt in the hand holding the handpiece. SUMMARY OF THE INVENTION

It is an objective underlying the present invention to provide for an improved electric appliance for personal care avoiding at least one of the disadvantages of the prior art and/or further developing the existing solutions. A more particular objective underlying the invention is to provide for an improved drive unit structure reducing vibrations onto the installation environment surrounding the drive unit without sacrificing drive efficiency under high oscillation frequencies. A still further objective is to allow for less restrictive manufacturing tolerances of the drive components without reducing performance characteristics such as stable oscillation frequencies, sufficient amplitudes and low vibrations. Another objective is to avoid complicated mounting structures and to allow for installation of the drive unit into housing elements forming handpieces without requiring additional space or redesigning established ergonomic housings. To achieve at least one of the aforementioned objectives, the electric appliance provides for a rotatory degree of freedom for the drive unit although said drive unit is of the linear oscillation type. More particularly, the drive support supporting the drive unit onto a mounting structure of the installation environment is adapted to provide for at least one axis of rotation for at least one of the drive components of the drive unit allowing said at least one drive component to rotate relative to the mounting structure. Due to such additional rotatory degree of freedom, the drive component may not only linearly oscillate, but also may pivot or rotate to some degree, what significantly reduces vibrations onto the installation environment. Torques caused by

manufacturing tolerances and phase offset of the pulsating electric current or magnetic fields are not transferred to the mounting structure of the installation environment, thus allowing for a more comfortable handling of the electric appliance.

These and other advantages become more apparent from the following description giving reference to the drawings and possible examples.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 : is a perspective partial view of a small-sized electric appliance for personal care in terms of an electric shaver having a shaver head including three cutter elements drivable in an oscillating manner by a linear type drive unit received within the shaver housing forming the shaver's handpiece,

Figure 2: is a plane view of a drive unit including magnetic-type drive components supported for linear oscillation and the surrounding mounting structure, wherein a drive support connecting the drive unit to the mounting structure is shown and includes leaf springs providing for a rotatory degree of freedom for the drive unit,

Figure 3: a partial perspective view of one of the leaf springs of the drive support connecting the drive unit to the surrounding mounting structure,

Figure 4: a plane view of a prior art drive unit of the linear oscillation type where the drive unit is rigidly fixed to the surrounding mounting structure, and

Figure 5: a perspective view of the drive unit of Fig. 4.

DETAILED DESCRIPTION OF THE INVENTION

In order to avoid transfer of rotatory vibrations due to torques generated in the drive unit due to tolerances or phase offset, at least one of the drive components of the drive unit is allowed to execute rotatory movements relative to the surrounding mounting structure. More particularly, at least the active drive component coupled to the functional element to be driven is allowed to rotate relative to said mounting structure, wherein said drive component is a linear drive component oscillating along a substantially linear displacement or oscillation axis. According to an aspect, the drive support supporting the drive unit onto the mounting structure is adapted to provide for at least one axis of rotation for said at least one of the drive components of the drive unit allowing the drive component to rotate relative to the mounting structure about said at least one axis of rotation. Due to such axis of rotation, the drive unit is separated from the surrounding mounting structure in terms of rotatory vibrations and torques. In order to dampen rotatory movement of the drive unit about said additional rotatory degree of freedom, the drive support may include a damper dissipating rotatory energy of the drive unit and retarding movements of the drive unit about said at least one axis of rotation. In addition or in the alternative to such damper, the drive support may include at least one elastic restoring element for elastically restoring the drive unit into a rotatory or angular home position about said at least one axis of rotation. Such elastic restoring element and the aforementioned damper may form an integral unit, wherein in particular the elastic restoring element may provide for some damping effect. In other words, such elastic restoring element may form the aforementioned damper dissipating the rotatory energy of the drive unit relative to the rotatory degree of freedom.

According to an aspect, the drive support may include a pair of spring elements supporting the drive unit relative to the mounting structure, wherein said pair of spring elements may define a four point joint supporting the drive unit rotatable about said axis of rotation. The spring elements may form a spring bar linkage allowing rotatory movements of the respective component of the drive support to which the spring bar linkage is connected, wherein the spring bar linkage may elastically deform to allow such rotatory movement. More particularly, the aforementioned spring elements may bend and/or yield and/or be tensioned and/or be compressed, thus allowing rotatory movement of the component of the drive unit to which the spring elements are connected.

More particularly, the aforementioned four point joint defined by said pair of spring elements may have two points fixed with the mounting structure and two other points fixed with the drive unit, wherein the two points fixed with the drive unit may move relative to the mounting structure due to elastic deformation of the spring elements, thus allowing for rotatory movement of the drive unit.

The drive support and/or the aforementioned spring elements may be adapted such that the axis of rotation about which the drive support may rotate is substantially coaxial with a center of rotational vibrations of the drive components oscillating relative to each other and/or coaxial with a center axis of geometrical, polar inertia of said drive unit. The aforementioned pair of spring elements may include leaf springs on opposite sides of the drive unit which leaf springs may be arranged at an obtuse angle relative to each other. More particularly, the said leaf springs, with their longitudinal axis, may define a virtual intersection point which is positioned in a center region of the drive unit. For example, the leaf springs on opposite sides of the drive unit may be offset from a centerline going through both opposite sides towards an end portion of the drive unit so that the leaf springs arranged at an obtuse angle relative to each other define, with their longitudinal axes said virtual intersection point close to the center of the drive unit. According to an aspect, the drive support may provide for multiaxial rotatory degree of freedom so that the drive unit and/or at least the active drive component thereof may rotate about a plurality of axes of rotation.

According to an aspect, there is at least an axis of rotation extending transverse to the oscillation axis of the drive unit and/or transverse to a longitudinal axis of a handpiece of the electric appliance. More particularly, the axis of rotation may extend substantially perpendicular to a plane defined by the oscillation axis of the drive unit and a virtual line connecting the drive unit with the functional element to be driven and/or substantially perpendicular to a plane defined by the oscillation axis of the active drive component of the drive unit and the oscillation axis of the functional element to be driven, for example the cutter element of a shaver oscillating transverse to the shaver's longitudinal axis.

The aforementioned rotatory degree of freedom of the drive support may be provided only for one drive component, in particular the active drive component coupled to the functional element to be driven. In the alternative, said rotatory degree of freedom may be provided for both drive components oscillating relative to each other. Such degree of freedom for both first and second drive components may help in avoiding angular mismatch of the two components with each other so that is becomes possible to provide for only very small gaps between the first and second drive components, thereby increasing efficiency.

Said first and second drive components may be movably supported in different manners so as to allow for linear oscillation relative to each other. For example, the first and second drive components may be supported separately relative to the mounting structure. In the alternative, the first and second drive components may be connected to each other by means of a pendulum bearing or a four point bearing allowing for linear oscillation of the drive components relative to each other. For example, a pair of pivot bars or leaf springs may connect the first drive component to the second drive component such that said first and second drive components may oscillate relative to each other along an oscillation axis, wherein the pivot bars or leaf springs may pivot and/or bend to allow such relative oscillation.

The drive support mounting the drive unit to the surrounding mounting structure may connect such pivot bars or leaf springs of the pendulum bearing or four point linkage to the mounting structure. More particularly, the aforementioned leaf springs arranged at an obtuse angle relative to each other may connect such pendulum bearing or said pivot bars or said leaf springs connecting the two drive components to each other to the surrounding mounting structure.

The aforementioned mounting structure of the installation environment may be a mounting frame received within a housing and/or held in a fixed position within a handpiece of the electric appliance. In the alternative, the mounting structure may be formed directly by an inner surface of a housing element or the handpiece.

The electric appliance for personal care may be a male electric shaver including a handpiece formed by a shaver housing and a shaver head pivotably supported onto said handpiece about one or more pivot axes allowing for self-adaption of the shaver head to the contour of the skin to be shaved.

The shaver head may include only one cutter element, but the shaver head also may include two, three or more cutter elements. The shaver head may include further cutting or non-cutting functional elements such as a thermal element for cooling or heating a skin portion to be shaved, or a long-hair cutter, or fluid applicators to apply fluids such as deodorants, balms or lubricants onto the skin. The transmission train for transmitting the drive power and movements of the electric linear motor to the at least one cutter element may have varying architectures and structures depending on the type of motor and the arrangement thereof. For example, the drive unit may include a reciprocating pin coupled to the aforementioned cutter element or undercutter directly or via an oscillation bridge allowing for pivoting of the cutter element relative to the angular orientation of the longitudinal axis of said pin.

These and other features become more apparent from the example shown in the drawings.

As can be seen from Fig. 1 , shaver 1 may have a shaver housing 2 forming a handpiece for holding the shaver, which shaver housing 2 may have different shapes such as - roughly speaking - a substantially cylindrical shape or box shape or bone shape allowing for

ergonomically grabbing and holding the shaver, wherein such shaver housing has a longitudinal shaver housing axis z due to the elongated shape of such housing, cf. Fig. 1.

On one end of the shaver housing 2, a shaver head 3 is attached to the shaver housing 2, wherein the shaver head 3 can be pivotably supported about a shaver head pivot axis x extending substantially perpendicular to the aforementioned longitudinal shaver housing axis z. The shaver housing 2 may have a pair of support arms projecting from the shaver head end of the shaver housing 2 between which support arms a carrier structure of the shaver head 3, for example in terms of a shaver head frame, can be pivotably mounted about said shaver head pivot axis x.

As can be seen from Fig. 1 , the shaver head 3 may include a several cutter elements 4, wherein only one or three or four or more of such cutter elements 4 may be provided. Such cutter elements 4 for short hair cutting may form block-like undercutters with a plurality of shearing blades cooperating with a shear foil covering the respective cutter elements 4. The said cutter elements 4 may have an elongated shape with a longitudinal axis extending substantially parallel to the aforementioned shaver head pivot axis and/or substantially parallel to the cutting oscillation axis 8 along which the cutter elements 4 are driven in an oscillating manner.

Additionally one or more long hair cutter elements are provided within the shaver head. In this example one or two long hair cutter elements are arranged between the short hair cutter elements. Any arrangement of the cutter elements relative to each other may be possible. As can be seen from Fig. 2, the drive unit 5 which may be received within the shaver housing 2 (or within the shaver head) to drive the cutter elements 4 at the shaver head 3, is of the linear oscillating type and may include a first drive component 6 and a second drive component 7 which may oscillate relative to each other along an oscillation axis 9. Said first drive component 6 may form the active drive component coupled to the aforementioned cutter elements 4 by means of a transmitter 10 which may include a transmitter pin 11 extending from the drive unit 5 towards the shaver head 3. Such transmitter pin 11 may be directly coupled to the cutter elements 4, for example by means of a pivot bearing allowing for an additional transverse degree of freedom to compensate for pivoting of the shaver head 3. In the alternative, the transmitter 10 may include further transmission components such as a transmission bridge as it is per se known in the art.

As shown by Figures 2 and 3, said first drive component 6 may include one or more oscillating, magnetic coils 12, whereas the second drive component 7 may include one or more permanent magnets, wherein the drive unit 5 further may include one or more resonance springs 13 arranged between the first and second drive components 6 and 7 to promote oscillation of the first and second drive components 6 and 7 relative to each other at natural frequency. As can be seen from Fig. 2, the first and second drive components 6 and 7 may be connected to each other by means of a pendulum bearing 14 which may include a four point linkage formed by pendulum bars 15, cf. Fig. 2. Such pendulum bars 15 may have some elasticity or may be formed by leaf springs that may bend, thus allowing relative movement of the drive components. In addition or in the alternative, said pendulum bars 15 may connect to the first and second drive components 6 and 7 at pivot joints allowing for pivoting of the pendulum bars 15 relative to the drive components 6 and 7. In other words, the pendulum bars 15 may bend and/or pivot to allow linear oscillation of the drive components 6 and 7 relative to each other. Thus, both drive components 6 and 7 may execute linear oscillation, wherein such oscillation is effected in a sort of reverse motion. When the first drive component 6 moves to the left, the second drive component 7 moves to the right and vice versa.

The drive unit 5 is supported onto a mounting structure 16 by means of a drive support 17. Said mounting structure 16 may be a frame structure surrounding the drive unit 5, wherein, as shown by Fig. 2, such mounting frame may form a closed ring or rectangle surrounding the drive unit 5. Said mounting structure 16 may be rigidly fixed to the shaver housing 2, for example by means of mounting flanges 18, or may be held in the shaver housing 2 in a fixed position by means of suitable fixation means such as screws or latching means. As shown by Figures 2 and 3, the drive support 17 mounting the drive unit 5 to the mounting structure 16 may include a pair of leaf springs 19 which are sufficiently resilient or yielding or a sort of soft so that the leaf springs 19 may bend and be deformed so as to allow for rotation of the drive unit 5 relative to the mounting structure 16.

Such leaf springs 19 may connect the aforementioned pendulum bearing 14 to the mounting structure 16, wherein the leaf springs 19 may be fixed to the pendulum bars 15.

As shown by Figures 2 and 3, said leaf springs 19 may extend at an obtuse angle so that longitudinal axes indicated by dashed line 20 of said leaf springs 19, more particularly of a central portion of said leaf springs 19 have a virtual intersection point 21 which is positioned in a center region of the drive unit 5. More particularly, the aforementioned leaf springs 19 may be arranged on opposite sides of the drive unit 5 and offset towards an end region of said drive unit 5, in particular the end region or end portion of the drive unit 5 facing the shaver head 3. The position and angular orientation of the leaf springs 19 is adapted such that the aforementioned intersection point 21 is positioned at least neighboring a center of the drive unit 5.

More particularly, the drive support 17 and/or the leaf springs 19 thereof are adapted such that the axis of rotation 22 about which the drive unit 5 may rotate relative to the mounting structure 16, goes through the center of possible rotatory vibrations of the drive unit 5.

Due to bending of the leaf springs 19, the drive unit 5 may execute multiaxial pivoting or rotating. The drive support 17, however, provides for at least one axis of rotation 22, wherein such at least one axis of rotation 22 may extend in a direction transverse to the oscillation axis 9 of the drive unit 5 and/or transverse to the longitudinal axis z of the housing or handpiece of the shaver 1. Referring to Figures 2 and 3, said axis of rotation 22 may extend perpendicular to the drawing plane, e.g. along axis y in Fig 1.

In contrast to Figures 2 and 3, Figures 4 and 5 show a conventional drive unit structure where the drive unit 5 as such is basically similar to the drive unit 5 of Figures 2 and 3, wherein, however, the pendulum bearing allowing for oscillation of the two drive components relative to each other is rigidly fixed to the mounting structure 16. Reference numeral 23 designates such rigid connection in Fig. 4. The shaver head 3 may include further functional elements such as a long-hair cutter which may be arranged between the aforementioned pair of cutter elements 4.

The cutter elements 4 can be driven in an oscillating manner along cutting oscillation axis 8. In addition to such cutting movements, the cutting elements 4 can be pivotable and movable in directions transverse to said cutting oscillation axis 8, i.e. e.g. around axis y as well.

In the context of the present application, the indefinite article "a/an" shall have the meaning "at least one/or more" if not specified contrarily. Furthermore, geometrical definitions such as "perpendicular to" or "parallel with" shall be understood as "at least substantially perpendicular to" or "at least substantially parallel with" to include the exact mathematical meaning, but not being restricted to. Still further, dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm."