Patent Description:
Personal care appliances such as a razor include a functional device (e.g. a cutter), a driving bridge coupled to the cutter, a motor, and a linkage extending between the motor and the driving bridge. The selection of linkage depends on a location of the motor relative to the driving bridge. A motor being proximal to the driving bridge may employ an eccentric. The eccentric may fit in a slot of the driving bridge, the slot forming opposing driving surfaces for the eccentric to push against. However, if the motor is moved further away from the driving bridge, the eccentric may be unsuitable due to loads exerted on the eccentric.

Therefore, a lever may be employed as the linkage. However, a driving bridge designs for use with a motor eccentric may be unsuitable for a lever. This is primarily because a driving surface for use with an eccentric is typically small, e.g. the driving bridge may be comparatively thin. In this way, friction may be reduced. However, when a thin driving bridge is used with a lever, it may be difficult to align the lever with the slot of the driving bridge because of stack tolerances along a length of the personal care appliance.

An example of prior art is given by the patent documentation <CIT>.

It is an aim of the subject-matter of the present disclosure to improve on the prior art.

According to a first aspect of the present invention, there is provided a personal care appliance comprising: a handle; a functional device at a head of the handle; a driving bridge for driving the functional device, the driving bridge comprising a slot; a motor within the handle; and a lever coupled between the motor and the driving bridge for reciprocally driving the driving bridge back and forth, the lever comprising a cylinder at a tip inserted in the slot of the driving bridge, the slot being provided between opposing driving surfaces, wherein the cylinder is inclined with respect to the driving bridge, wherein a ratio, D/H, of a diameter, D, of the cylinder to a height, H, of the respective driving surfaces, is greater than one.

The cylinder being inclined with respect to the driving bridge means that the driving bridge designed for engagement with a motor eccentric can be used with a lever so that the motor can be moved away from the driving bridge.

In an embodiment, an angle of inclination of the cylinder with respect to the driving bridge is between <NUM> and <NUM> degrees.

In an embodiment, the angle of inclination is around <NUM> degrees.

In an embodiment, the ratio D/H is around <NUM>.

In an embodiment, a length of the cylinder is between about <NUM> and <NUM>.

In an embodiment, the length of the cylinder is governed by: L = e/tan(α)+L_start, where L is the length of the cylinder measured in mm, e is an error range between a highest and a lowest positions of the cylinder in the slot measured in mm, α is the angle of inclination of the cylinder with respect to the slot, and L_start is starting value for the cylinder length in mm assuming e is zero.

In an embodiment, the error, e, is around <NUM>.

In an embodiment, the cylinder axis is substantially parallel to an axis of rotation of the lever.

In an embodiment, the lever comprises a motor end opposite the tip, the motor end having a slot, wherein the motor comprises an eccentric driving mechanism extending in a direction of an axis in which the handle extends, wherein the eccentric driving mechanism is accommodated within the slot of the motor end of the lever.

In an embodiment, the eccentric driving mechanism comprises a substantially spherical shaped tip contained within the slot of the motor end of the lever. In this way, the tip of the eccentric driving mechanism will be less likely to jam in the slot.

In an embodiment, the motor end of the lever comprises a guide for guiding the eccentric driving mechanism therein during assembly. In this way, assembly is made easier and quicker.

In an embodiment, the guide of the motor end of the lever comprises opposing ramps.

In an embodiment, the driving bridge comprises a guide for guiding the tip of the lever to the slot of the driving bridge during assembly. In this way, assembly is quicker and easier.

In an embodiment, the guide of the driving bridge comprises opposing inclined surfaces.

In an embodiment, the lever extends in a direction substantially parallel to the axis in which the handle extends, and optionally wherein the motor is positioned at a distal end of the handle to the head.

In an embodiment, the personal care appliance is a shaver, and the functional device comprises a cutter.

According to an example, there is provided a personal care appliance comprising: a handle; a functional device at a head of the handle; a driving bridge for driving the functional device, the driving bridge comprising a slot; a motor within the handle; and a lever coupled between the motor and the driving bridge for reciprocally driving the driving bridge back and forth, the lever comprising a cylinder at a tip inserted in the slot of the driving bridge, wherein the cylinder is inclined with respect to the driving bridge.

These and other aspects of the present invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

The embodiments of the present inventions may be best understood with reference to the accompanying figures, in which:.

Although the example embodiments have been described with reference to the components, modules and units discussed herein, such functional elements may be combined into fewer elements or separated into additional elements. Various combinations of optional features have been described herein, and it will be appreciated that described features may be combined in any suitable combination. In particular, the features of any one example embodiment may be combined with features of any other embodiment, as appropriate, except where such combinations are mutually exclusive. Throughout this specification, the term "comprising" or "comprises" means including the component(s) specified but not to the exclusion of the presence of others.

The personal care appliance may be a, for example, handheld apparatus used for personal care or grooming. Personal care appliances include cleaning appliances, skin treatment appliances, hair removal appliances, massage devices, etc. Generally, personal care appliances perform a treatment or an operation to a human or animal body.

Hair cutting appliances and hair grooming appliances are well-known in the art and may comprise, for instance, shavers, razors, trimmers, epilators, hair styling appliances and combinations thereof. Typically, hair grooming appliances comprise an electric motor that is arranged to drive a cutting unit (or cutter), for instance a blade set, so as to effect a hair cutting and/or grooming operation. More generally, hair cutting appliances may be also referred to as grooming appliances.

With reference to <FIG> and <FIG>, a personal care appliance in the form of a hair cutting appliance, or shaver, is provided. The personal care appliance includes a guard <NUM>, a functional device (in this case a cutter) <NUM>, a driving bridge <NUM>, and a linkage <NUM>. The cutter <NUM> and the guard <NUM> both have a plurality of teeth. The cutter <NUM> cooperates with the guard <NUM> by moving back and forth in a reciprocal manner to cut hairs between the respective teeth. The cutter <NUM> is connected to the driving bridge <NUM>. The driving bridge includes a slot <NUM>. The slot is oriented orthogonally to a direction of movement of the driving bridge <NUM>.

The linkage <NUM> in <FIG> and <FIG> is an eccentric driving mechanism because the motor (not shown) is located proximally to the driving bridge <NUM>. The eccentric driving mechanism comprises an elongate stem extending parallel to a rotational axis of the motor. However, the elongate stem is not inline with the rotational axis of the motor but is offset. In this way, the stem provides the eccentric driving mechanism.

The slot <NUM> is provided between opposing driving surfaces. During operation, the eccentric driving mechanism pushes against the driving surfaces to move the driving bridge <NUM> in a reciprocal manner during rotation of the motor. To reduce friction between the eccentric driving mechanism and the driving surfaces, the driving surfaces can be comparatively thin. In this way, the driving surfaces have reduced contact surface with the motor eccentric. The driving bridge comprises opposing ramps <NUM> to help guide the eccentric driving mechanism into the driving bridge <NUM> during assembly.

With reference to <FIG> and <FIG>, a personal care appliance is provided where the motor is located further from the driving bridge in comparison to the personal care appliance of <FIG> and <FIG>. In other words, the motor is distal from the driving bridge. To accommodate the distally located motor, the linkage is a lever. The lever includes a tip <NUM>, a hub <NUM>, and a motor end. The tip includes a substantially spherical ball to reduce friction with the driving surfaces. The hub <NUM> includes a hole for mounting to an axle (not shown) anchored to a handle of the personal care appliance. A centre of a hub provides a rotational axis of the lever.

The motor end <NUM> includes a fork <NUM> providing a slot <NUM> for receiving a motor eccentric <NUM> therein.

It will be appreciated that stacked tolerances along the personal care appliance cause alignment issues between the tip <NUM> and the slot <NUM>.

This issue is addressed by the personal care appliance in the form of a shaver of <FIG>. Features not described in relation to <FIG> but which are common to the personal care appliances described in relation to <FIG> may be considered to have the same reference sign incremented by <NUM>.

With reference to <FIG>, the personal care appliance comprises a handle (not shown), a functional device <NUM> at a head of the handle, a driving bridge <NUM> for driving the functional device, a motor (not shown) within the handle, and a lever <NUM> between the motor and the driving bridge <NUM> for reciprocally driving the driving bridge back and forth. The motor is positioned at a distal end of the handle to the head.

The functional device in this case comprises a cutter <NUM> because the personal care appliance is a shaver. The functional device also includes a guard <NUM> as in the personal care appliances of <FIG>.

As above, the driving bridge <NUM> comprises a slot <NUM>. The slot <NUM> is formed between two opposing surfaces of the driving bridge which may be called driving surfaces. The driving surfaces have a height H. The driving bridge comprises a guide <NUM> for guiding a tip <NUM> of the lever <NUM> into the slot <NUM> during assembly. The guide <NUM> includes opposing inclined surfaces.

The lever <NUM> extends substantially in a same direction as an axis of rotation of the motor, which is substantially the same as an axis in which the handle extends.

The lever <NUM> comprises a cylinder <NUM> at the tip <NUM>. The cylinder <NUM> has a diameter D. The cylinder <NUM> is inserted in the slot <NUM> of the driving bridge <NUM>. The driving bridge <NUM> is inclined with respect to the cylinder. Put differently, the cylinder <NUM> is inclined with respective, or relative, to the slot <NUM>. In other words, a direction in which the slot extends is inclined relative to a central axis of the cylinder. In this way, it is easier to align the cylinder <NUM> with the driving surfaces of the driving bridge <NUM> compared to a configuration where the slot <NUM> may extend in a direction parallel to, or in line with, a central axis of the cylinder <NUM>. The central axis of the cylinder <NUM> may be parallel to an axis of rotation of the lever. Moreover, the diameter D of the cylinder <NUM> is greater than the height H of the driving surfaces. Thus, the ratio of the diameter D of the cylinder <NUM> to the height H of the driving surface has a value greater than one. The ratio D/H may range, for example, from <NUM> to <NUM>. The ratio D/H may be for example <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc. An optimal D/H ratio value to manage manufacturing tolerances may be around <NUM>. <FIG> shows a D/H ratio of around <NUM>. By having a D/H ratio greater than one, the driving bridge <NUM> used to drive the functional device remains suitable, or in other words, compatible with an eccentric driving mechanism, which comprises an elongated stem of diameter D. Thus, it will be appreciated by those skilled in the art that the inclined driving bridge <NUM> for driving the functional device may be compatible with personal care appliances that incorporate either an eccentric driving mechanism or a lever <NUM>, as described in the context of the invention.

In some embodiments, an angle of inclination of the cylinder with respect to the driving bridge is between <NUM> and <NUM> degrees. The angle of inclination may be around <NUM> degrees. With this in mind, a length of the cylinder may be between <NUM> and <NUM>. The length of the cylinder may be governed using formula (<NUM>) below.

In formula (<NUM>), L is a length of the cylinder in mm, e is an error between a highest and lowest positions of the cylinder in the slot measured in mm, α is the angle of inclination of the cylinder with respect to the slot, and L_start is a starting value for the cylinder length in mm assuming e is zero. The error, e, may be around <NUM>.

The lever <NUM> may comprise a motor end opposite the tip <NUM>. The motor end may include a slot <NUM>. The motor may comprise an eccentric driving mechanism <NUM> extending in a direction of an axis in which the handle extends. The eccentric driving mechanism <NUM> may be accommodated within the slot <NUM> of the motor end of the lever <NUM>.

The eccentric driving mechanism <NUM> may comprise a substantially spherical shaped tip <NUM> contained within the slot <NUM> of the motor end of the lever <NUM>. The motor end of the lever comprises a guide <NUM> for guiding the eccentric driving mechanism therein during assembly. The guide <NUM> of the motor end of the lever comprises opposing ramps.

Claim 1:
A personal care appliance comprising:
a handle;
a functional device (<NUM>) at a head of the handle;
a driving bridge (<NUM>) for driving the functional device, the driving bridge comprising a slot (<NUM>);
a motor within the handle; and
a lever (<NUM>) coupled between the motor and the driving bridge (<NUM>) for reciprocally driving the driving bridge (<NUM>) back and forth, the lever (<NUM>) comprising a cylinder (<NUM>) at a tip inserted in the slot (<NUM>) of the driving bridge (<NUM>), the slot (<NUM>) being provided between opposing driving surfaces;
wherein the cylinder (<NUM>) is inclined with respect to the driving bridge (<NUM>),
characterized in that a ratio, D/H, of a diameter, D, of the cylinder to a height, H, of the respective driving surfaces, is greater than one.