Personal grooming device

Abstract

The subject-matter of the present disclosure relates to a personal grooming device (100). The device comprises a cutter (102) and a cutter-guard (106) which are configured to, in combination, provide a cutting action via motion of the cutter (102) with respect to the second plurality of teeth (114). The device (100) also comprises a skin touching guard (108) comprising a third plurality of teeth (162) configured to receive the second plurality of teeth (114), wherein a cumulative thickness (164) of the second plurality of teeth (114) and third plurality of teeth (162) is configured to be substantially uniform with respect to a length (166) of the second plurality of teeth (114).

Description

[0001] PERSONAL GROOMING DEVICE

[0002] FIELD OF THE INVENTION

[0003] The subject-mater of the present disclosure relates to a personal grooming device, and in particular various parts thereof which improve a quality of cut provided by the personal grooming device.

[0004] BACKGROUND OF THE INVENTION

[0005] As will be familiar to those in the art, hair trimmers - and similar hair cuting devices - usually comprise a cuter having sharpened tooth-like blades which oscillate from side to side with respect to a fixed (stationary) guard component to provide a cuting action.

[0006] In recent times it has been determined that there are advantages (both to manufacturing and user experience) to providing a guard which is formed from a combination of metal and plastic parts. The metal part generally being provided as the cuting counter-part to the cuter, and the plastic part generally provided for yielding beter skin feel for the user.

[0007] However, it can be difficult to manufacture a trimmer with a combined metal and plastic guard whilst retaining a high quality cut; in particular when the metal part is formed from thin metal sheet.

[0008] Reference document US 2022 / 0410419 Al relates to a hair cuting kit that comprises a comb implement that can be releasably atached to a cuting unit having a stationary blade.

[0009] It is thus an aim of the present disclosure to improve on the prior art.

[0010] SUMMARY OF THE INVENTION

[0011] The above noted problems could be at least partially solved by a personal grooming device according to claim 1.

[0012] According to a first aspect of the present invention, there is provided a personal grooming device comprising a cuter and a cuter-guard comprising a second plurality of teeth which are configured to, in combination, provide a cuting action via motion of the cuter with respect to the second plurality of teeth. The device further comprises a skin touching guard comprising a third plurality of teeth configured to receive the second plurality of teeth, and a cumulative thickness of the second plurality of teeth and third plurality of teeth is configured to be substantially uniform with respect to a length of the second plurality of teeth. In this way a length of hair that is cut by the device is substantially the same no mater where on a tooth (with respect to its depth) the hair is cut.

[0013] In an example, the second plurality of teeth are configured to be substantially planar with uniform thickness. In an example, the cumulative thickness at a rear end of the second and third plurality of teeth is less than or equal to 1.5 times a cumulative thickness of a front end of the second and third plurality of teeth, further preferably less than or equal to 1.2 times the cumulative thickness of the front end of the second and third plurality of teeth.

[0014] In an example, the third plurality of teeth each comprise a tip portion arranged to align with a tip of the each of the second plurality of teeth.

[0015] In an example, the skin touching guard is formed from a plastic, while the cutter-guard is formed from a sheet metal. In an example, a thickness of the sheet metal is less than about 2.5% of a full width of the cutter-guard.

[0016] These and other aspects of the present invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

[0017] BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The embodiments of the present inventions may be best understood with reference to the accompanying figures, in which:

[0019] Fig. 1 shows an example cutter and cutter guard within an example personal grooming device;

[0020] Fig. 2 shows an example arrangement of a cutter-guard within a personal grooming device;

[0021] Fig. 3 shows a sectional view with respect to the line A-A illustrated in Fig. 1;

[0022] Fig. 4 shows a sectional view with respect to the line B-B illustrated in Fig. 1;

[0023] Fig. 5 shows an example cutter-guard;

[0024] Fig. 6 shows another example cutter-guard;

[0025] Fig. 7 shows an example of a curved cutter guard;

[0026] Fig. 8 shows an example arrangement of a skin touching guard;

[0027] Fig. 9 shows an example configuration of a curved cutter-guard before assembly of the personal grooming device;

[0028] Fig. 10 shows an example arrangement of a curved cutter-guard, cutter, and skin touching guard during assembly of the personal grooming device;

[0029] Fig. 11 shows an example skin touching guard;

[0030] Fig. 12 shows an improved example skin touching guard;

[0031] Fig. 13 shows a side view of Fig. 12;

[0032] Fig. 14 shows an example tip portion of a skin touching guard and cutter guard;

[0033] Fig. 15 shows an example arrangement of a cutter-guard and skin touching guard;

[0034] Fig. 16 shows another example arrangement of a cutter-guard and skin touching guard;

[0035] Fig. 17 shows yet another example arrangement of a cutter-guard and skin touching guard; Fig. 18 shows further example arrangements of a tip portion of a cutter-guard and skin touching guard - Fig. 18(a) shows a first arrangement, Fig. 18(b) a second arrangement, Fig. 18(c) a third arrangement, and Fig. 18(d) a fourth arrangement;

[0036] Fig. 19 shows further example arrangements of a tip portion of a cutter-guard and skin touching guard - Fig. 19(a) shows a first arrangement, Fig. 19(b) a second arrangement, Fig. 19(c) a third arrangement, and Fig. 19(d) a fourth arrangement; and

[0037] Fig. 20 shows an example improved arrangement of a tip portion of a cutter-guard and skin touching guard.

[0038] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] The example embodiments relate to a personal grooming device and in particular a cutterguard component thereof. The example embodiments are provided to address one or more of the problems outlined above. Other advantages will be appreciated from the detailed discussion herein.

[0040] Fig. 1 shows an example personal grooming device 100, which may be, for example, a hair trimmer. The device 100 comprises a cutter 102 and a guard portion 104. The guard portion 104 comprises a cutter-guard 106, which is preferably metallic, and a skin touching guard 108, which is preferably plastic. The cutter 102 and cutter-guard 106 are configured to, in combination, provide a cutting action via motion of the cutter 102 with respect to a front portion 110 of the cutter-guard 104. More specifically, the cutter 102 comprises a first plurality of teeth-like blades 112 which slidingly oscillate over a second plurality of teeth-like blades 114 comprised by the front portion 110 of the cutterguard 106, cutting hair positioned in between adjacent teeth while it does so.

[0041] Figs. 2 to 5 show the guard portion 104 and cutter-guard 106 thereof in more detail. Here it can be seen that the cutter-guard 106 also comprises a rear portion 116. The rear portion 116 comprises a flat section having a substantially flat planar surface 118 which is arranged to be parallel to a similarly flat planar surface 120 of the cutter 102. Suitably, a ball bearing 122 may be disposed in between, and in contact with, the two planar surfaces 118, 120, to allow for motion of the cutter 102 relative to the cutterguard 106. As shown, two such ball bearings are provided, one on each side (left-right) of the cutter 102 / cutter-guard 106.

[0042] In the present example the cutter-guard 106 is preferably formed from a sheet metal. Here, sheet metal includes the cutter-guard having a width less than or equal to 2.5% of a full width of the cutter-guard 106. By way of example, the cutter-guard may be about 0.3mm thick.

[0043] It will be appreciated that sheet metals are highly susceptible to deformation and difficult to shape. As such, to aid in providing a suitably flat (i.e., smooth) surface 118 for contact with the ball bearing 122, in the present example the rear portion 116 is designed to have a greater stiffness than the front portion 110. Ensuring the ball bearing 122 can roll freely over the surface 118 without irregularity allows for a more consistent cutting action of the device 100. Flatness of the surface 120 is provided by virtue of the cutter 102 being formed from a thicker, much more rigid, piece of metal which therefore is easier to shape to be flat and not prone to deformation.

[0044] To provide the desired stiffness, the rear portion 116 also comprises a bent section 124 which is bent away from the flat section. That is, the bent section 124 is bent at an angle relative to the substantially flat planar surface 118. Put another way, starting from a substantially flat sheet metal shaped as a cutter-guard 106, the substantially flat rear portion 116 thereof is bent along a line 126 extending across its full width - that is, the aspect of the cutter-guard 106 parallel to the direction of the cutting motion, here left-right - to create the angled bar 124. Bending the sheet metal in this way provides the rear portion 116 of the cutter-guard 106 with the desired stiffness.

[0045] Moreover, the bent section 124 is preferably bent away from the cutter 102, as shown; this sort of bend acts to somewhat stretch the flat surface 118, further enhancing smoothness. To accommodate the cutter-guard 106 into the device 100, and aid in securing the cutter-guard in position, the device 100 may comprise a suitable groove, or slot, 128 into which the bent section 124 is receivable. The groove may be formed as part of a general body of the device 100, or considered part of the skin touching guard 108.

[0046] It will be appreciated that a range of angles are suitable for the bend 126. In one example, the bent section 126 may be bent away from the flat section 118 at an angle between about 30 degrees and about 120 degrees. In another example, the bent section 124 may be bent away from the flat section 118 at an angle between about 45 degrees and about 90 degrees - preferably 90 degrees. In yet another example, the bent section 124 may be bent away from the flat section 118 by an angle of about 60 degrees.

[0047] Connecting the rear portion 116 to the front portion 110 is a connector portion 130. The connector portion 130 is provided to better decouple the stiffness of the rear portion 116 from the stiffness of the front portion 110; that is, so that the front portion can have greater flexibility which aids its purpose as a cutting tool.

[0048] Suitably, the connector portion 130 comprises at least one connector arm 132 connecting the rear portion 116 to the front portion 110 of the cutter-guard 106. Preferably, as shown the connector portion 130 comprises a pair of connector arms 132a, 132b joining the front portion 110 to the rear portion 116. Suitably, the connector arm(s) 132 is / are configured to be stiff in an x-y direction - that is, in the plane defined by the planar surface 118, which is substantially parallel with the plane of the cutting action - and flexible in the z direction - that is, the plane orthogonal to the cutting action.

[0049] Suitably, the stiffness of the connector portion 132 may be adjusted as desired by changing at least one of a type of metal from which the cutter-guard 106 is formed, a length of the connector arm(s) 132, width of the connector arm(s) 132, or thickness of the connector arms 132 (which is generally determined by a thickness of the metal sheet).

[0050] On dimensionality, a cumulative width 134 of the at least one connector arm 132 is preferably less than or equal to 70% of the overall width 136 of the cutter-guard 106. By way of example, the width of each connector arm may be about 3 mm, so that in the example shown of two arms, the cumulative width is 6 mm. Furthermore, a length 138 of the connector arm(s) 132 may be less than or equal to 75% of a total length 140 of the cutter-guard 106. Moreover, in the example shown of a pair of connector arms 132, a centre line 142 of each arm 132a, b may be displaced from a centre line 144 of the cutter-guard by about 33% of the overall width 136; for example, by about 9 mm to about 10 mm.

[0051] On material, in a preferred implementation, the metal sheet is Stainless steel AISI301, comprising a tensile strength of 1300-1450 N / mm2 and a yield strength of about rpO.2% = 600-1300 MPa, further preferably 800-1100 MPa.

[0052] Fig. 6 shows a further optional modification of the connector portion 130, whereby each connector arm 132a, b, comprises an area of localised weakening 146. In this example, the localised weakened is provided by a notch cut into each connector arm 132. It will of course be appreciated that other techniques for generating localised weakening can be applied: e.g., through holes. Adjusting the amount of localised weakening (i.e., the degree of material removed from each connector arm 132) suitably allows for changing the stiffness of the connector portion 130 and thereby the stiffness decoupling between front and back portions 110, 116.

[0053] Figs. 7 to 10 show an example arrangement of another example cutter-guard 106, which may include any suitable combination of the aforementioned features.

[0054] In this example the cutter-guard 106 further comprises a curvature 148 in a direction which is transverse to the substantially flat plane of the cutting action. That is, taking the front portion 110 of the cutter-guard in the previous examples to be substantially flat in the x-y plane of the cutting action, then the curvature 148 in the present example travels along the x-direction (i.e., left to right) and extends into a z plane (i.e., upwards / downwards).

[0055] More specifically, it is the front portion 110 of the cutter-guard 106 that is curved, and suitably the curvature may extend across the full width 136 of the front potion 110. That is, there is no part of the front portion which sits entirely in the x-y plane. In the example shown the curvature 148 is convex, although it will be appreciated that a concave shape is also possible.

[0056] Optionally, the cutter-guard may also comprise a second curvature 150 which is also transverse to the plane of the cutting action (i.e., extends in the z direction) but in a direction orthogonal to the first curvature 148. That is, where the first curvature 148 is along the x-direction (left-right) of the device 100, the second curvature 150 is in the y-direction (front-back). In the example shown the second curvature 150 is concave, but may also be convex, and may be the opposite type of curvature to the first curvature 148. Preferably, at least the front portion 110 comprises the second curvature 150, although as shown the second curvature may also extend through the connector portion 130 (that is, the connector arm(s) 132 may be curved along the length), and further optionally into the rear portion 116. That is, the second curvature 150 may extend the full length (y direction front to back) of the cutter-guard 106.

[0057] It should be appreciated however that the curvatures 148, 150 only exists when the cutterguard 106 is in a relaxed state (e.g., freshly formed / manufactured). When the cutter-guard is installed in the device 100, it is arranged to rest on the skin touching guard 108 (or other part of the device 100), and the cutter 102 arranged on top of the cutter-guard 106 to push against it. That is, the cutter-guard 106 is sandwiched in between the cutter 102 and skin touching guard 108, which are suitably arranged on opposite sides of the cutter-guard 106. In doing so the cutter 102 deforms the front portion 110 so that the cutter-guard 106 substantially matches the shape of the abutting surface of the cutter 102. In this way the front portion 110 is made to conform to the cutter 102 which limits the possibilities for a gap between the opposing sets of tooth-like blades 112, 114. In particular, the first transverse curvature 148, which travels in the x-direction, causes conformity of the cutter / cutter-guard in the x-direction, while the second transverse curvature 150 causes conformity in the cutter / cutter-guard y-direction. In particular, the curvature helps push the tips of the tooth-like blades 114 of the cutter-guard 106 into the tips of the toothlike blades 112 of the cutter 102.

[0058] Suitably, the cutter 102 preferably comprises a flat surface abutting the cutter-guard, so that the front portion is deformed to be flat. In this way the (previously curved) cutter guard 106 is made flat in the x-y plane in which the cutting action occurs. Moreover, this ensures that the overall shape of the cutter guard 106 is flat. That is, that the front portion 110 rear portion 116 are in a single plane.

[0059] Suitably, the skin touching guard 108 may comprise at least two support points 152, 154 which the cutter-guard 106 is pushed against by the cutter 102 in order to bend the cutter-guard 106 into shape. More preferably, the skin touching guard comprises three such points which therefore define the x- y plane in which the (now flat) cutter-guard resides in the device 100. Two support points 152, 154 are preferably provided to contact the front portion 110, separated in the x-direction (i.e., towards the left and right of the front portion 110). The third support point 156 is arranged to contact the rear portion 116, preferably substantially centrally. A height of each of the support points 152, 154, 156 is preferably from about 10 microns to about 30 microns, as this has been determined to be high enough to ensure the flattening effect, but low enough not to have any hairs getting stuck in between metal cutter-guard 106 and plastic skin guard 108.

[0060] Suitably, the front pair of support points 152, 154 are arranged at the same distance 158 from the edge of the front portion 110. Further preferably the support points are arranged in the outer 30% of the front portion; that is, within 30% from of the edge of the front portion 110 when taking the full width of the front portion as 100%.

[0061] Suitably, a ratio of a height of the curvature 148 above a plane defined by the front pair of support points 152, 154, to a depth a of the curvature below the plane defined by the pair of support points 152, 154 may be greater than 1. This ratio helps ensure that there is no gap between the cutter 102 and cutter-guard 106. Further preferably, the ratio may be greater than 2, more preferably greater than 3. The higher the ratio, the more the gap between the cutter 102 and cutter-guard 106 is reduced.

[0062] Returning to the main examples, Figs. 11 and 12 show the skin touching guard 108 in more detail. Fig. 11 shows an example skin touching guard 108 which comprises a front portion 160 shaped to correspond to the front portion 110 of the cutter-guard 106. More specifically, the front portion 160 comprises a third plurality of teeth 162, which are configured to receive the second plurality of teeth 114 of the cutter-guard 106. That is, the second plurality of teeth 114 are dimensioned so as to sit on top of, and within the dimensions of, the third plurality of teeth.

[0063] As can be seen, the front portion 160 increases in thickness as it progresses from the front rearward. Depending on where in the depth of the teeth a hair is cut, the residual hair length will differ; for example, a hair cut at position 164a will be shorted than a hair cut at 164b.

[0064] Figs. 12 & 13 show an improvement to Fig. 11 whereby the front portion 160 of the skin touching guard 108 is configured for a substantially uniform thickness along its depth. Suitably, when the second plurality of teeth 114 are received onto the third plurality of teeth 162, a cumulative thickness 164 of the second plurality of teeth 114 and third plurality of teeth 162 is substantially uniform with respect to a length 166 of the (now combined / overlapping) plurality of teeth 114, 162. Put another way, the thickness of the cutter-guard 106 and the skin touching guard 108 are substantially uniform along the depth 166 of the teeth. Suitably, as the second plurality of teeth 114 are substantially planar, the third plurality of teeth 162 may also be substantially planar; although it will be appreciated that the effect could still be achieved with variable geometry teeth.

[0065] Herein, substantially uniform may be taken to mean that a change in the cumulative thickness over the depth 166 of the teeth may be less than or equal to about 1.5 times. That is, a thickness at the rear end 168 of the (combined) teeth may be less than or equal to 1.5 times a thickness at the front end 170 of the tooth. Further preferably, a thickness of the rear end 168 of the teeth is less than or equal to 1.2 times the thickness of the front end 170 of the teeth.

[0066] Suitably, each of the third plurality of teeth also comprise a tip portion 172 which is configured to align with a tip 190 of the received tooth of the second plurality of teeth. Preferably, the second plurality of teeth 114 are configured to abut the tip portion 172, however this may not always be guaranteed. Manufacturing tolerances and stresses on the device 100 during use may cause a gap 174 between a second tooth tip and the tip portion 172, as shown in Fig. 14. During trimming, hair can become trapped in the gap 174 which can cause discomfort and reduce cutting effectiveness.

[0067] Figs. 15 to 17 show an example device 100 which addresses the issue of the gap 174. Here the example device 100 further comprises a biasing member 176 configured to bias the tips 178 of the second plurality of teeth to abut the tip portions 172 of the third plurality of teeth 162.

[0068] In the example of Fig. 15, the member 176 takes the form of a resilient arm 176 which is anchored to the skin touching guard 108. In particular, the arm 176 may span between two points 180, 182 on the device 100 and engage with a hook 184 provided on the cutter-guard 106 which is suitably configured to receive the arm 176 (or part thereof). Suitably, the hook 184 is positioned laterally in the (negative) y direction with respect to the points 180, 182, thereby exerting the required biasing force on the arm 176 (in the positive y direction). In the example of Fig. 16, the member 176 takes the form of a spring 176 formed into the body of the cutter-guard 106 which is configured to push against the skin touching guard 108, thereby providing the desired biasing force. Suitably, the skin touching guard 108 may comprise a protrusion 186 extending into the plane of the cutter-guard 106 for the spring to push against.

[0069] In the example of Fig. 17, the member 176 comprises a barb which is configured to frictionally engage a pair of protrusions 188 on the skin touching guard 108 which are biased towards each other.

[0070] Fig. 18 shows a further solution to the problem shown by Fig. 14, which can be applied in addition to, or separately to, the biasing technique just described. Here, the tips 172 of the third plurality of teeth are shaped in combination with the tips 190 of the first plurality of teeth to minimise the possibility of hair entering the gap 174. In particular, the tips 172, 190 are designed so that it is difficult for a single hair to penetrate the gap 174 between two adjacent teeth.

[0071] For example, in Fig. 18(a) the tips 172, 190 are each curved, so that a horizontal hair cannot get stuck in both teeth. In Fig. 18(b), the length of adjacent teeth are different. In Fig. 18(c), the teeth shape is irregular. In Fig. 18(d), the tips are provided with different shapes, and optionally the tip 190 is mismatched to the tip 172.

[0072] Fig. 19 shows a problem that can arise with the tip portions 172, 190, however, when the tips 190 of the metal cutter-guard 106 do not sufficiently correspond to the tips 172 of the plastic skin touching guard 108. Fig. 19(a) shows a gap 174, much like Fig. 14. Fig. 19(b) shows a comer mismatch between the tip portions 172, 190. Fig. 19(c) shows a bad transition due to a mismatch in shape between the tip portions 172, 190. Fig. 19(d) shows a height difference between the tip portions 172, 190. Each of these configurations have a problem of hindering, and sometimes completely stopping, hair flow through the cutting teeth of the device 100.

[0073] Suitably, Fig. 20 shows an example whereby each tooth in the third plurality of teeth 162 comprises a tip portion 172 configured to envelop the tip 190 of a received tooth of the second plurality of teeth 114. That is, the tip 190 of the cutter-guard tooth sits within the three-dimensional profile of the tip portion 172 which the tip 190 abuts. In this way the metal cutter-guard (or specifically teeth thereof) may be prevented from sticking out from the skin touching guard 108. In an example where the cutter-guard 106 is not formed from a thin metal sheet, then it may be appropriate for the skin touching guard 108 to be moulded (or otherwise bonded) direct to the cutter-guard 106, in which case the present embodiment may be achieved by over-moulding the tip portion(s) 172 around the tip portion(s) 190.

[0074] Suitably, in the example of Fig. 20 the shape of the tip portion 172 is configured to substantially match a shape of the tip 190 of the received tooth. Suitably, in a preferred example, each of the tips 190 of the second plurality of teeth 114 are provided with the same shape (e.g., Figs 18(a)— (c)), and likewise each of the tips 172 of the third plurality of teeth 162. While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments.

[0075] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfil the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMSClaim 1. A personal grooming device (100), comprising: a cuter (102); and a cuter-guard (106) comprising a second plurality of teeth (114), wherein the cuter and cuter-guard (106) are configured to, in combination, provide a cuting action via motion of the cuter (102) with respect to the second plurality of teeth (114); and a skin touching guard (108) comprising a third plurality of teeth (162) configured to receive the second plurality of teeth (114), wherein a cumulative thickness (164) of the second plurality of teeth (114) and third plurality of teeth (162) is configured to be substantially uniform with respect to a length (166) of the second plurality of teeth (114).Claim 2. The grooming device (100) of claim 1, wherein the second plurality of teeth (114) are configured to be substantially planar with uniform thickness.Claim 3. The grooming device (100) of claim 1 or claim 2, wherein the cumulative thickness at a rear end (168) of the second and third plurality of teeth (114, 162) is less than or equal to 1.5 times a cumulative thickness of a front end (170) of the second and third plurality of teeth (114, 162).Claim 4. The grooming device (100) of claim 3, wherein the cumulative thickness at the rear end (168) of the second and third plurality of teeth (114, 162) is less than or equal to 1.2 times the cumulative thickness of the front end (170) of the second and third plurality of teeth (114, 162).Claim 5. The grooming device (100) of any preceding claim, wherein the third plurality of teeth (162) each comprise a tip portion (172) arranged to align with a tip (190) of the each of the second plurality of teeth (114).Claim 6. The grooming device (100) of claim 5, wherein the skin touching guard (108) is formed from a plastic.Claim 7. The grooming device (100) of any preceding claim, wherein the cuter-guard (106) is formed from a sheet metal.Claim 8. The grooming device (100) of claim 7, wherein a thickness of the sheet metal is less than about 2.5% of a full width of the cutter-guard (106).

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