protection board

Abstract

According to one aspect, a guard plate 10 for a set of cutting blades 100 of a hair-cutting device is provided, the guard plate having a skin-facing surface 12 and an opposing blade-facing surface. The shield has a plurality of close shave trimming teeth 16 distributed longitudinally along an edge 18 of the shield, the close shave trimming teeth having a thickness of less than 120 microns, each tooth extending from the edge of the shield to a corresponding tip, raised ridges 22 having a curved shape in a plane perpendicular to the longitudinal direction, the ridges raising from the teeth toward the skin-facing surface of the shield, the curved shape not extending beyond a 30 degree envelope defined by a line passing through the edge of the shield and offset 30 degrees from a tangent at the edge of the shield, and a pressure relief zone between the teeth and the ridges defining a continuous surface, with a transition 32 between the pressure relief zone and the ridges such that as the shield is passed over a user's taut skin, the skin does not directly follow the contour of the transition, thereby locally relieving pressure from the skin. The ridge has a plurality of openings 48 distributed at least within a pressure recovery zone of the ridge, the pressure recovery zone being defined between a rise point and a tangent point, the rise point being the location of a peak perpendicular distance from the skin-facing surface of the shield to a pressure relief line, the pressure relief line being defined by a tangent to the ridge in a plane perpendicular to the longitudinal direction, the tangent line passing through the edge of the shield, and the tangent point being the location of the tangent of the pressure relief line on the ridge.

Description

[Technical Field]

[0001] The present invention relates to a guard plate for a blade set for a hair-cutting appliance, as well as to a blade set, a cutting unit and a hair-cutting appliance having such a guard plate. [Background technology]

[0002] Various types of facial hair cutters are available, such as trimmers that have two sets of reciprocating teeth on the edge of a plate, and foil shavers that have a foil with openings for receiving hairs and cutting blades that cut the hairs in those openings. Typically, foil shavers provide a closer shave than trimmers, but close-shave trimmers, which have a very thin plate with one set of teeth that contacts the skin, can also achieve a very close shave. Summary of the Invention [Problem to be solved by the invention]

[0003] Previously considered configurations have not successfully combined a foil shaver and trimmer into a single unit because foil shavers require a dome-shaped configuration for good cutting performance, but the dome-shaped configuration prevents the close trimmer teeth from having the continuous skin contact required for a close shave, thereby reducing the close trimmer's performance.

[0004] WO 2015 / 158923 discloses a cutting blade set having a curved protective plate with trimming teeth and an apertured foil body.

[0005] The present invention provides a guard plate for a blade set for a hair-cutting appliance, as well as a blade set, a cutting unit and a hair-cutting appliance having such a guard plate. [Means for solving the problem]

[0006] According to a first particular aspect, there is provided a guard plate for a set of cutting blades for a hair-cutting device, having a skin-facing surface and an opposite cutting-blade-facing surface, the guard plate comprising: a plurality of close-shave trimming teeth longitudinally distributed along an edge of the guard plate, each tooth extending from the edge of the guard plate to a corresponding tip, the close-shave trimming teeth having a thickness of less than 120 microns; ridges having a curved shape in a plane perpendicular to the longitudinal direction so as to be raised from the teeth towards the skin-facing surface of the guard plate, the curved shape of the ridges not extending beyond a 30-degree envelope defined by a line passing through the edge of the guard plate and offset 30 degrees from a tangent at the edge of the guard plate; and a continuous surface a pressure relief zone between the teeth defining a surface and the ridges, where there is a transition between the pressure relief zone and the ridges, so that when the protective plate is passed over a user's taut skin, the skin does not directly follow the contour of the transition, thereby locally reducing pressure from the skin; and the ridges have a plurality of openings distributed within at least the pressure recovery zone of the ridges, the pressure recovery zone being defined between a rise point and a tangent point, where the rise point is the location of the peak perpendicular distance from the skin-facing surface of the protective plate to the pressure relief line, the pressure relief line being defined by a tangent to the ridges in a plane perpendicular to the longitudinal direction that passes through the edge of the protective plate, the tangent point being at the location of the pressure relief line on the ridges. The openings are distributed in the ridge within at least the first 1 mm from the rising point in the pressure recovery zone.

[0007] The surface of the shield at the transition has a height change of at least 0.1 mm, the height being defined by the perpendicular distance between the skin-facing surface and the pressure relief line.

[0008] The plurality of openings are further distributed across the top of the ridge adjacent the pressure recovery zone of the ridge.

[0009] The pressure relief zone may be a planar surface.

[0010] The escutcheon may have a plurality of close shave trimming teeth distributed longitudinally along both edges of the ridge. There may be a pair of pressure relief zones located on either side of the ridge, each pressure relief zone being located between the ridge and a tooth along one edge of the escutcheon. The ridge may have an apex flanked by two pressure recovery zones, each pressure recovery zone adjacent to a pressure relief zone, the ridge having a plurality of openings distributed between at least the two pressure recovery zones.

[0011] The apron may be formed from a single, integral plate.

[0012] The curved shape of the ridges may extend beyond a 5 degree envelope defined by a line passing through the edge of the apron and offset by 5 degrees from a tangent at the edge of the apron.

[0013] Each of the teeth can extend from the edge to a tip where it is bent toward the cutting edge facing surface and pointed rearward toward the edge, connecting to the cutting edge facing surface to form a buttress to reinforce the tooth.

[0014] The openings may be uniformly distributed throughout the pressure recovery zone. The ratio of the area of ​​the openings to the total area of ​​the pressure recovery zone may be at least 40%.

[0015] According to a second aspect, there is provided a cutting blade set for a hair cutting device, comprising a protective plate according to the first aspect and a cutting plate that is received in the protective plate and is expected to cooperate with the protective plate to cut hair.

[0016] According to a third aspect, there is provided a cutting assembly comprising a cutting blade set according to the second aspect and a drive unit configured to reciprocate the cutting plate relative to a protective plate.

[0017] According to a fourth aspect, there is provided a hair-cutting appliance comprising a cutting assembly according to the third aspect attached to a handle.

[0018] These and other aspects will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0019] Exemplary embodiments will now be described, by way of example only, with reference to the following drawings, in which: [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 shows a schematic perspective view of an exemplary apron. [Figure 2] FIG. 2 schematically illustrates a simplified side view of the exemplary apron of FIG. [Figure 3] FIG. 3 shows a schematic exploded view of the cutting blade set with the protective plate of FIGS. [Figure 4] FIG. 4 shows a schematic cross-sectional view of a cutting assembly with the cutting blade set of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] FIG. 1 shows an exemplary guard plate 10 for use in a hair-cutting device for trimming hair, such as a beard trimmer, and FIG. 2 shows a simplified side view of the guard plate 10 geometry.

[0022] Shield 10 comprises a single, unitary plate having a skin-facing side 12 and an opposite, blade-facing side 14. Shield 10 comprises a plurality of close shave trimming teeth 16 distributed longitudinally parallel to a longitudinal axis 50 along which Shield 10 extends.

[0023] Each close trimming tooth 16 extends from an edge of the escutcheon 10 to a corresponding tip 20. At the tip 20 of each close trimming blade 16, the teeth 16 are bent toward the blade-facing surface 14 (i.e., away from the skin-facing surface 12) and then bent back at a turn-up portion toward the edge 18 where they rejoin to form a continuous plate portion.

[0024] The close trimming teeth 16 are configured to cooperate with cutting teeth 112 on a cutting plate 110 (described in more detail below with reference to FIG. 3) to cut hair. The close trimming teeth 16 have a thickness (of the plate) of approximately 90 microns so that the hair is cut as close as possible to the skin. In other examples, the close trimming teeth have a thickness of less than 100 microns or less than 120 microns to ensure a close shave.

[0025] In this example, the close trimming teeth 16 are located on opposite edges of the escutcheon 10 (i.e., on either side of the major axis 50), allowing the escutcheon 10 to be used to cut hair in two different directions. In other examples, the close trimming teeth may be located along only one edge of the escutcheon.

[0026] Shield 10 includes raised portions 22 that have a curved shape in a plane perpendicular to longitudinal axis 50 (e.g., the plane shown in FIG. 2), which in this example is also perpendicular to edge 18 of Shield 10. Raised portions 22 are raised in a direction from close trimming teeth 16 toward skin-facing surface 12 of Shield 10 (i.e., away from cutting blade-facing surface 14). The shape of the Shield in this example is constant along longitudinal axis 50. In other examples, the shape of the Shield can vary along the longitudinal axis.

[0027] The shield 10 further includes a pair of pressure relief zones 30 on either side of the raised portions 22, with each pressure relief zone 30 located between one set of close shaving teeth 16 and the raised portions 22 along one edge 18. In this example, each pressure relief zone 30 has a continuous, flat portion approximately 1 mm long between the corresponding close shaving tooth 16 and the raised portions 22 on the shield. In other examples, the pressure relief zones can define any continuous surface and can be of any suitable length, less than or greater than 1 mm. In other examples, the pressure relief zones are at least 0.3 mm long to ensure sufficient pressure reduction against the skin during use.

[0028] In this example, the ridges 22 are contoured to have a height difference of about 1 mm from the pressure relief zone 30. The ridges 22 are for foil-type cutting elements and improve skin contact necessary for a close shave. In other examples, the ridges can have any suitable height difference from the pressure relief zone, such as more or less than 1 mm, or at least 0.5 mm.

[0029] Between each pressure relief zone 30 and the ridge 22 is a transition 32 such that each pressure relief zone 30 is defined between a corresponding edge 18 of the apron 10 and the corresponding transition 32. The two transitions 32 in this example each have a recess with a sharp corner (i.e., a discontinuity). In other examples, the transitions may comprise recesses with chamfered corners, or an otherwise flat or continuous surface culvert or groove from the pressure relief zone. The transitions may have any contour that is recessed from the skin line that a user's skin follows between the teeth and ridges during use.

[0030] Each transition section 32 ensures that when the protective plate is passed over the user's taut skin in use, the skin does not directly follow the contours of the protective plate at that transition section 32, and the pressure applied by the protective plate 32 to the user's skin is locally reduced or completely eliminated at that transition section.

[0031] On either side of the ridge 22, a pressure relief line 44 is defined by a line tangent to the ridge 22 that passes through each edge 18 of the apron 10 in a plane perpendicular to the major axis 50 (only one pressure relief line 44 is shown in Figure 2).

[0032] The ridge 22 includes an apex 34 adjacent to and sandwiched between two pressure recovery zones 36. Each pressure recovery zone 36 is adjacent to a pressure relief zone 30. Each pressure recovery zone 36 is defined between a rise point 38 (in the transition section 32) and a tangent point 46 located at the point where a pressure relief line 44 meets the ridge 22. The rise point 38 is defined as the point on the shield 10 where the vertical distance between the pressure relief line 44 and the skin-facing surface 12 of the shield 10 (shown by arrow 40 in FIG. 2 ) reaches a peak (i.e., a maximum). In this example, the change in vertical distance between the pressure relief line 44 and the skin-facing surface 12 of the shield 10 in the pressure relief zones 30 and 36 (referred to herein as a change in height) is 0.1 mm. In some examples, the change in height can be greater than 0.1 mm, such as 0.3 mm or greater. In other words, the peak height at the rising point 38 can be greater than 0.1 mm, and in a preferred example, greater than 0.3 mm. The greater the height change at the transition 32, the more pronounced the effect of the pressure relief zone 30 in reducing the pressure locally applied to the skin, since the user's skin is less likely to be able to follow the contours of the transition as the shield 10 is applied and moved over the user's skin. Reducing the pressure applied to the skin in this region improves hair cutting at the ridge 22, as this reduction in pressure can cause hair to protrude or redirect from the skin toward the shield 10.

[0033] A plurality of openings 48 are distributed only in the pressure recovery zone 36 of the ridge 22 (best seen in FIG. 1 , where the peaks 34 and pressure recovery zone 36 are depicted with dotted lines indicating tangent points 46). The openings 48 are configured to capture hairs to be cut. In this example, the openings 48 are circular and have a diameter of 300 microns. In other examples, the diameters may range from 200 to 400 microns or 250 to 350 microns, or may be non-circular and have dimensions up to 500 microns. In still other examples, the openings may have different shapes and sizes. In some examples, the openings may be distributed in both the pressure recovery zone and the peak. The openings in the pressure recovery zone are more effective at capturing hairs than the openings in the peaks due to the transition to the ridges and the pressure relief zone.

[0034] In this example, the openings 48 are uniformly distributed throughout the pressure recovery zone 36, at least within the first 1 mm of the rising edge 38 of the pressure recovery zone 36. Having openings 48 within at least the first 1 mm of the pressure recovery zone also makes them more effective at capturing hairs because they are within the diameter of the first few hairs. The ratio of openings 48 to the total area of ​​the plate in the pressure recovery zone in this example is approximately 40%. In other examples, the ratio of openings 48 to the total area can be greater than 40%. The higher the ratio of openings in the pressure recovery zone 36, the greater the likelihood that hairs will be captured in the openings 48 for cutting. In other examples, the openings may not be distributed throughout the entire pressure recovery section. The ratio of openings to plate material may apply only to the area where the openings are located, such as the area bounded by two opening diameters from the center of each opening. It will be understood that in some examples, only one pressure recovery zone may have openings.

[0035] The ridges 22 of the apron 10 do not extend beyond the ridge envelope 24 (shown in FIG. 2 ) to reduce the risk of significantly impeding the cutting ability of the close shave teeth 16 as the apron 10 is passed over the user's skin during use. The ridge envelope 24 is defined by a line passing through the edge 18 of the apron 10 and offset by an angle α of 30 degrees from a tangent to the edge 18 of the apron 10. In this example, the tangent to the edge 18 of the apron 10 is aligned with the surface of the pressure relief zone 30 because the pressure relief zone 30 is planar and extends from the close shave teeth 16. In some examples, the angle α of the ridge envelope may be 25 degrees. Restricting the ridges 22 within the ridge envelope 24 reduces the adverse effect of the ridges on the performance of the close trimming teeth 16, which require consistent contact with the skin.

[0036] In this example, the ridges 22 extend beyond a minimum envelope defined by a line (not shown) that passes through the edge 18 of the shield 10 and is offset at a 5 degree angle from a tangent at the edge 18 of the shield 10. Extending the ridges beyond the minimum envelope helps ensure that sufficient pressure is applied to the skin above the ridge envelope for best cutting performance of the ridges.

[0037] Although the apron 10 has been described as having a single, integral plate, in some instances the apron may have multiple plates welded or otherwise attached together.

[0038] It will also be understood that in other instances, where there is only one set of close shaving teeth, there may be only a single pressure relief zone and ridge, a single transition between the pressure relief zone and the ridge, and a single pressure recovery zone on the ridge. In some instances, the ridge (and thus the transition and raised portion) may not extend the entire length along the longitudinal axis of the apron, but may only be present on a portion of the apron. Furthermore, in some instances, there may be two sets of close shaving teeth extending along the edge of the apron, which may lie in offset planes from each other (i.e., the two edges and sets of teeth may not be in the same plane), in which case the envelope of the ridge is defined by each edge.

[0039] Although the apron 10 is defined as extending along a major axis 50, in some instances the apron may extend along a curve such that it extends in a curved manner.

[0040] FIG. 3 shows an exploded view of a blade set 100 including an apron 10 and a cutting plate 110 configured to be received on the apron 10 at the blade-facing side 14 of the apron 10 .

[0041] The cutting plate 110 has cutting teeth 112 on both edges that are configured to cooperate with the close shave trimming teeth 16 on either side of the shield 10 to trim hair. The cutting plate 110 also has a plurality of cutting edges (blades) 114 that extend from the face of the cutting plate 110 toward the shield 10. Each of the cutting edges 114 has a contour that corresponds to the contour of the raised portions 22 of the shield 10, such that the cutting edges 114 are configured to cooperate with the openings 48 in the shield 10 to cut hair.

[0042] The cutting blade set 100 in this example further includes a guard support plate 200 that is configured to be received by the guard plate 10 on the cutting blade-facing side 14 between the close shaving teeth 16 and the folded-over portion of the guard plate 10 to support the folded-over portion of the guard plate 10 and thereby support the close trimming teeth 16. The guard support plate 200 also includes a plurality of teeth 202 that are configured to align with the close shaving blades 16 of the guard plate 10 and to cooperate with the teeth 112 of the cutting plate 110 to cut hair.

[0043] The protective support plate 200 includes a slot 204 that passes through the thickness of the plate forming the protective support plate 200. The slot 204 extends along a longitudinal direction that is parallel to the major axis 50 of the protective plate 10 when the cutting blade set 100 is assembled. The slot 204 is configured to receive a lever 302 that is connected to a drive unit 300 (shown in FIG. 4).

[0044] In another example, instead of having the guard support plate, the folded portion can be connected to the blade-facing surface of the guard plate to form a buttress for each close shaving tooth. Both the guard support plate and buttress provide reinforcement for the close shaving teeth 16 and allow for thinner plates at the close shaving teeth 16, providing a reliable close shave during use.

[0045] 4 shows a cutting assembly 400 comprising a cutting blade set 100 and a drive unit 300 being applied to a user's skin 102. The cutting blade set 100 comprises a protective plate 10, a cutting plate 110 and a protective support plate 200, with the skin-facing side 12 of the protective plate 10 moving over the user's skin 102 as shown applied to the skin 102 to shave or trim hair thereon.

[0046] The drive unit 300 includes a lever 302 that is received through the slot 204 in the guard support plate 200 and pivotally connected to the cutting plate 110. Accordingly, the drive unit 300 is configured to reciprocate the cutting plate 110 relative to the guard plate 10 to cut hair at the close trimming teeth 16 and openings 48.

[0047] 4 shows the cutting assembly 400 being passed over a user's skin 102 toward the right side of the page (indicated by the arrow). The user's skin 102 flows over the escutcheon 10, contacting the close shaving teeth 16 and over the ridges 22 of the escutcheon 10. From FIG. 4, it can be seen that the skin 102 does not follow the contours of the skin-facing side 12 of the escutcheon 10 in the pressure relief zone 30 due to the transition 32 to the ridges 22. Thus, there is less or no pressure from the escutcheon 10 on the skin 102 in the pressure relief zone 30. The less or no pressure in the pressure relief zone 30 causes hairs on the skin 102 to protrude toward the escutcheon 10 and be captured by the openings 48 in the pressure recovery zones 36 of the ridges 22. These openings must be located within the pressure recovery zone 36 (i.e., between the rise point and 1 mm beyond that point towards the apex 34) to ensure that they can capture hair from the pressure relief zone 30.

[0048] Although the openings 48 are described as being within at least the first 1 mm of the ridge 22 from the rise point 38 (i.e., the peak height from the pressure relief line 44), in some instances the openings may be within the first 300 microns of the ridge from the rise point (e.g., within the width of a hair from the rise point). The closer the openings 48 in the ridges 22 are to the rise point 38 of the shield 10, the greater the likelihood of capturing a hair.

[0049] The symmetrical nature of the cutting assembly 400 relative to the apron 10 means that the cutting assembly 400 can be used to cut hair in either direction.

[0050] The cutting assembly 400 can be mounted on a handle to provide a hair-cutting device that can be easily manipulated as required by the user.

[0051] Variations to the disclosed embodiments can be understood and effected by those skilled in the art, from a study of the drawings, the disclosure, and the appended claims, in practicing the principles and techniques described herein. In the claims, the word "comprising" does not exclude other elements or steps, and the singular does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be interpreted as limiting the scope.

Claims

1. 1. A protective plate for a set of cutting blades for a hair-cutting device, the protective plate having a skin-facing surface and an opposite cutting blade-facing surface, the protective plate comprising: a plurality of close shave trimming teeth distributed longitudinally along an edge of the escutcheon, each close shave trimming tooth extending from the edge of the escutcheon to a corresponding tip, the escutcheon having a thickness at the close shave trimming tooth of less than 120 microns; a raised portion having a curved shape in a plane perpendicular to the longitudinal direction so as to be raised from the close shave trimming teeth toward the skin-facing surface of the shield plate, the curved shape of the raised portion not extending beyond a 30-degree envelope defined by a line passing through the edge of the shield plate and offset 30 degrees from a tangent at the edge of the shield plate; a pressure relief zone between the close shave trimming teeth and the ridges defining a continuous surface, with a transition between the pressure relief zone and the ridges such that when the guard is passed over a user's taut skin, the skin does not directly follow the contour of the transition, thereby locally reducing pressure from the skin; and the protuberance has a plurality of openings distributed within at least a pressure recovery zone of the protuberance, the pressure recovery zone being defined between a rising point and a tangent point, the rising point being a location where a perpendicular distance from the skin-facing surface of the protective plate to a pressure relief line is at a peak, the pressure relief line being defined by a tangent to the protuberance in a plane perpendicular to the longitudinal direction that passes through the edge of the protective plate, the tangent point being at a tangent position of the pressure relief line on the protuberance; protection plate.

2. 2. The apron of claim 1, wherein the plurality of openings are distributed in the raised portion within at least the first 1 mm from the rising point in the pressure recovery zone.

3. 2. The shield of claim 1, wherein the surface of the shield at the transition portion has a change in height of at least 0.1 mm, the height being defined by the perpendicular distance between the skin-facing surface and the pressure relief line.

4. 4. The apron of claim 1, wherein the plurality of openings are further distributed across the top of the ridge adjacent the pressure recovery zone of the ridge.

5. 4. The apron of claim 1, wherein the pressure relief zone is planar.

6. the apron has a plurality of close shave trimming teeth longitudinally distributed along opposite edges of the raised portion; a pair of pressure relief zones located on opposite sides of the raised portion, each pressure relief zone being located between the raised portion and a close shave trimming tooth along one edge of the guard plate; the raised portion has an apex flanked by two pressure recovery zones, each pressure recovery zone adjacent to the pressure relief zone, the raised portion having a plurality of openings distributed among at least the two pressure recovery zones; The protection plate according to any one of claims 1 to 3.

7. 4. The apron of claim 1, wherein the apron is formed from a single, integral plate.

8. 4. The protection plate of claim 1, wherein the curved shape of the ridge extends beyond a 5-degree envelope defined by a line that passes through the edge of the protection plate and is offset by 5 degrees from a tangent at the edge of the protection plate.

9. 4. The defogger of claim 1, wherein each of the close trimming teeth extends from the edge to a tip, at which point each close trimming tooth is bent toward the cutting edge-facing surface and directed rearward toward the edge, connecting to the cutting edge-facing surface to form a buttress for reinforcing the close trimming tooth.

10. 4. The apron of claim 1, wherein the openings are uniformly distributed throughout the pressure recovery zone.

11. 4. The protective plate of claim 1, wherein the ratio of the area of ​​the openings to the total area of ​​the pressure recovery zones is at least 40%.

12. A cutting blade set for a hair-cutting device, comprising: a protective plate according to any one of claims 1 to 3; and a cutting plate that is received in the protective plate and cooperates with the protective plate to cut hair.

13. A cutting assembly comprising the cutting blade set according to claim 12 and a drive unit for reciprocating the cutting plate relative to the protection plate.

14. A hair-cutting device comprising a cutting assembly according to claim 13 attached to a handle.

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