Blade unit for a wet razor

Description

[0001] The present invention relates to a blade unit for a wet razor. Furthermore, the invention relates to a wet razor with this blade unit.

[0002] Common razor blade units for wet shaving usually consist of two or more frame sections, with the lubricating strip located on one frame section and the foam edge on the other. In older units, the blades were riveted into the frame. Riveting becomes disadvantageous as the number of blades increases, as the distance between the rivet holes and the cutting edge increases significantly with each blade. Therefore, the blades must be of different widths, which results in very wide cutting units with three or more blades. A separate blade geometry is required for each blade position.

[0003] US Pat. No. 4,378,634 discloses a razor blade unit in which the blades can move up and down in slots within a housing against spring-loaded arms during shaving. Metal clamps mounted on the housing hold the blades in the slots and determine the positions of the cutting edges of the blades in the resting position. During production, the blades are first placed in the housing. A U-shaped clamp is then positioned over the housing and the blades. In a final step, the clamp legs are bent around the lower portion of the housing.

[0004] GB 2 531 491 A describes a razor blade cartridge with a first and a second housing part and a one-piece blade carrier to which at least two blades are attached. Fastening means serve to attach the first housing part to the second housing part, so that the blade carrier is movably mounted between the first housing part and the second housing part. The first housing part has an opening in which the cutting edges of the blades are arranged. Spring means urge the blade carrier and thus the cutting edges into the desired position in the opening in the first housing part.

[0005] The subsequently published EP 3 871 848 A1 discloses a razor blade unit for a safety razor with a housing, a plurality of blades, and a support element arranged in the housing. The support element comprises a base element and a blade carrier for each blade. The base element and the blade carriers are formed integrally from a plate-shaped metal sheet.

[0006] US 4,831,731 A describes a manual razor with a shaving head and a handle protruding from it. The shaving head contains at least two pairs of double razor blades, each blade having a shaving edge. The blades are firmly mounted longitudinally on the shaving head so that the shaving edges of all blades are exposed in a common plane.

[0007] DE 698 16 635 T2 describes a razor unit with a metal retaining clip for holding the blades.

[0008] The housing has a first lever portion extending outwardly over adjacent surface sections on two sides of the lever portion. The retaining clip includes a first end piece that has been bent over the first lever portion beyond the elastic limit of the clip. As the first end piece bends around the first lever portion, the lever portion is deformed and reduced in height by the applied pressure.

[0009] The blades of razor blade units are typically ground from narrow steel strips. Since steel is a relatively expensive material, efforts are made to minimize strip widths. To ensure good flushability of the razor blade unit, i.e., to flush out the spaces between adjacent blades, angled blades are generally used in units with three or more blades. The use of angled blades has long been known and can be found, for example, in EP 0 064 190, DE 25 18 499, and US Pat. No. 4,302,876.

[0010] In general, a key requirement for razor blade units is to precisely position the cutting edges of the multiple blades relative to each other and to the plane of skin contact. The more blades used in the razor blade unit, the more challenging this positioning becomes. If the cutting edges of one or more blades are not precisely aligned, there is either a risk of injury to the user or the shaving result is not optimal. Numerous previous patent documents also address the problem of precisely positioning the cutting edges.

[0011] For example, JP 2011-160818 A describes a razor with a plurality of blades and a guard extending longitudinally along the blades. The blades are supported by a common, cage-like carrier.

[0012] EP 3 075 498 A1 describes a razor head with a blade unit comprising a plurality of blades and a base element arranged at the rear of the blades. The base element has a bearing surface formed by deforming a steel plate. The bearing surface includes mounting surfaces and a cage-shaped support portion. An additional blade attachment plate comprises a plurality of step plates, corresponding to blade attachment portions, and bridge portions that connect the step plates to one another. Reinforcing plate portions are each bent from the step plates toward the inside of the blade unit. The step plates, the reinforcing plate portions, and the bridge portions are integrally formed with one another. Each blade is attached to the associated step plate via a plurality of weld points.

[0013] EP 2 279 062 B1 describes a razor blade unit comprising a housing, a guard arranged at a front portion of the housing, a cap arranged at a rear portion of the housing, and a plurality of blades, each comprising a sharp upper edge and a lower portion with a front and a rear side. Each blade has a blade carrier mounted between a plurality of pins, preferably made of polymer.

[0014] EP 1 990 143 B1 discloses a razor head having a blade body comprising a blade element, a blade base element, and an upper element. The blade element is secured between the blade base element and the upper element. The cutting edge of the blade body is exposed in the upper element. The base is elastically supported on the blade base element to be movable against a pressing force from the skin surface. The base is provided with an attachment base mounted on the blade base element and a blade body holding portion formed between a pair of attachment bodies. A leaf spring is mounted on both attachment bodies. The blade body holding portion is provided with a plurality of blade body attachment portions arranged in a stair pattern, each of the blade bodies being integrally movable together with each of the blade body attachment portions.

[0015] DE 27 50 196 A1 describes a head for a razor. Several razor blades are attached to an open housing frame at their ends. The cutting edges extend at a predetermined distance from a protective surface of the housing frame. Support surfaces for attaching the blades are provided above the housing frame. The support surfaces are arranged in a stepped manner and support the blades on the surface facing the shaving plane.

[0016] WO 2017 / 161341 A1 describes a razor cartridge with a one-piece inner blade frame for holding multiple blades. The blade frame has several angled arches that connect at least three guards. This results in a stepped configuration of the side edges of the blade frame. Attached to the underside of each extension of the guard is a razor blade, whose cutting edge extends into a gap between adjacent guards.

[0017] All previously known designs of so-called wet razor cartridges, i.e. interchangeable razor head units, result in conflicting requirements between the desired high precision of blade positioning on the one hand and the cheapest and simplest possible construction of the cartridges on the other.

[0018] One object of the present invention is therefore to provide an improved blade unit for a wet razor that ensures high positioning accuracy with respect to the cutting edges of the blades and, at the same time, has a very simple design requiring only a few individual parts. The blade unit should also be characterized by relatively low assembly effort and thus the lowest possible manufacturing costs. Finally, the invention aims to provide an improved wet razor.

[0019] To achieve the object of the invention, a blade unit according to the appended claim 1 and a wet razor according to claim 13 serve.

[0020] The blade unit according to the invention for a wet razor has a support frame with an outer side, which is directed toward the shaving plane during use, thus coming into contact with the user's skin surface, and an inner side. Furthermore, the blade unit comprises several elongated blades (also called main blades) positioned in the support frame, each with a cutting edge running transversely to a shaving direction.

[0021] The support frame of the blade unit has two opposite side sections that extend transversely to the cutting edges of the blades. Several parallel supports run between the side sections, with a free space between each support. Each support has a head section and a foot section angled to it. One of the blades is attached to each support, namely on the inside of the head section. This is a key difference from many previously known blade units, in which the blades are regularly attached to the outward-facing side of support surfaces. In the design according to the invention, the cutting edge of each of the blades is also located in the free space between adjacent supports and extends from the inside of the blade unit towards the outside.This leads to the particular advantage of better, more rigid support of the blade during shaving, as the force components generated when cutting hair press the blade against the inside of the head of the wearer, so that the blade rests against the head and is not lifted off the wearer. The remaining unsupported width of the blade at the moment of cutting is thus smaller than if the blade were attached to the outside of the wearer. This surprisingly leads to a better shaving result and, above all, to a longer blade lifespan, as the cutting edges of the blades are less deformed during shaving.

[0022] The opposite side sections of the support frame are flat, without steps or similar profiling.

[0023] The flat side sections thus form a reference surface that corresponds to the shaving plane and preferably exhibits no curvature. The cutting edges of the multiple blades are particularly preferably positioned in this shaving plane, whereby in special embodiments, a slight recess or even a slight protrusion relative to the shaving plane can be set for individual blades (protrusion).

[0024] The blades are preferably welded to the respective head section of the wearer. Particularly preferred is a laser welding process, creating several spaced-apart weld points per blade. The point-by-point attachment of the blades to the head section of the wearer is not critical, as the blade is pressed flat against the wearer during shaving.

[0025] The free spaces between the supports run largely parallel to the cutting edge located there. However, in each stop section, beginning at the side sections of the support frame, the free spaces run at an acute angle to the cutting edge. This makes it possible in a first embodiment for the cutting edges of the blades to each abut against a cutting edge stop at their two ends in the associated stop section. The cutting edge stop is formed as a projection that rises into the interior of the blade unit at a section of the support that runs at an acute angle to the cutting edge. Preferably, the projection is formed integrally with the support, for example by cutting the support into the stop section on one side and bending out a triangular projection so that one side edge of the triangular projection runs parallel to the cutting edge and acts as a stop edge for the cutting edge.The projection extends beyond the surface of the carrier toward the interior of the blade unit by only approximately the thickness of the blade. The stop edge preferably has a length between 0.5 and 3 mm.

[0026] According to a modified embodiment, the correct positioning of the cutting edges is achieved without the aforementioned cutting edge stop. Instead, a positioning recess is provided in the area of the stop section, into which a stopper of an external mounting device engages during assembly of the blades to the carriers. The two ends of the cutting edges strike these stoppers when the carrier frame and the blades are positioned in the mounting device, keeping the respective blade in the correct position during its attachment to the carrier.

[0027] A preferred embodiment is characterized in that the support frame is formed in one piece. The side sections and all supports are preferably formed from a metallic base plate. For this purpose, the required clearances are created, for example, by laser cutting, punching, or milling, followed by a bending process that may comprise multiple bending steps. The support frame does not need to be assembled from multiple parts. The blades are preferably attached to the supports after the bending process, particularly by laser welding. The one-piece design of the support frame allows the production of a blade unit (also referred to as a system razor cutting unit) made entirely of metal and thus offering significantly improved recyclability. Furthermore, this results in a novel, visually appealing, high-quality design.

[0028] To precisely position the blades, it is sufficient to place them on the head sections of the carriers and press the lateral ends of the cutting edges either against the stop sections formed in the carrier frame or against the stoppers of the assembly device until the laser welding process is completed. In the first embodiment, the accuracy of the blade positioning depends primarily on the accuracy of the stop sections, which can be adjusted using a precise but easily controllable bending process. The second embodiment, in which a positioning recess is provided in the area of the stop section, into which a stop engages during production, is therefore simpler to manufacture. In this case, the accuracy of the cutting edges positioning depends on the precise alignment of the carrier frame in an assembly device.

[0029] According to a modified embodiment, the cutting edge located in the free space between the supports protrudes beyond the head section by a predetermined amount, so that the cutting edge is located a predetermined amount above or below the shaving plane defined by the support frame. This amount can preferably be selected differently for the individual blades, as is common with multi-blade razors. The respective amount can be determined with high repeatability by positioning the respective cutting edge stop.

[0030] A further developed embodiment of the blade unit has a lubricating strip recess located in the support frame behind the blades, as viewed in the shaving direction. A lubricating strip is mounted in the lubricating strip recess, the longitudinal axis of which runs parallel to the cutting edges. The lubricating strip preferably comprises a water-soluble material that is applied to the skin during shaving, following the blade contact.

[0031] A further improved design has a pre-tensioner recess in the support frame, which is positioned in front of the blades in the shaving direction. A skin pre-tensioner strip can be positioned in the pre-tensioner recess, the longitudinal axis of which then extends parallel to the cutting edges. Such skin pre-tensioner strips are known in principle. After installation, the surface of the skin pre-tensioner strip lies in the shaving plane or helps determine it.

[0032] According to a modified embodiment, the skin tensioning strip itself can be part of the razor handle, so that the first one engages into the pretensioner recess when the razor handle and blade unit are coupled. This further facilitates later recycling of an all-metal blade unit, because the plastic skin tensioning strip is removed from the blade unit when it is removed.

[0033] A preferred embodiment comprises a trimmer blade holder, which is preferably formed integrally with the support frame and positioned at an angle to the other holders. A trimmer blade is attached to the trimmer blade holder, with its cutting edge not facing the shaving plane but approximately perpendicular to this plane. At the same time, the longitudinal axis of the cutting edge of the trimmer blade runs parallel to the longitudinal axes of the other blades. The trimmer blade serves the user, for example, to shave small areas of skin that cannot be reached by the main blades due to the surface area of the blade unit.

[0034] The support frame preferably comprises fastening elements for coupling a handle and / or a housing unit of the wet razor. Particularly preferably, the fastening elements are also formed integrally with the support frame, for example in the form of tabs, hooks, catches, or the like, which are preferably resilient in design to engage complementary elements on the handle and / or the housing unit. Particularly preferably, the support frame and the fastening elements for coupling the handle are made entirely of metal.

[0035] The invention further provides a wet razor comprising at least one handle and a blade unit directly or indirectly attached thereto according to the embodiments described above.

[0036] Further advantages and details of the invention will become apparent from the following description of a preferred embodiment, with reference to the drawings. They show: Fig. 1 is a perspective view from the rear of a first embodiment of a blade unit according to the invention; Fig. 2 is a perspective sectional view of the blade unit according to Fig. 1 with a support frame; Fig. 3 a plan view of a base plate of the support frame before a bending process; Fig. 4 a perspective detailed view of a support with a cutting edge stop; Fig. 5 a perspective detailed view of the support according to Fig. 4 with inserted blade; Fig. 6 a side view of the carrier according to Fig. 5 ; Fig. 7 a side sectional view of a second embodiment of the blade unit; Fig. 8 a detailed view of a stop portion of a cutting edge in the blade unit according to Fig. 7; Fig. 9 a side sectional view of the blade unit according to Fig. 7 in an assembly device; Fig. 10 a perspective view of a wet razor with the blade unit.

[0037] Fig. 1 shows a rear perspective view of a first embodiment of a blade unit 01 according to the invention. Fig. 2 shows a sectional view of this unit. The blade unit 01 is designed for a wet razor and is preferably configured as a replaceable unit, so that at least one handle of the wet razor (not shown) can be used multiple times, while the blade unit is replaced when worn and its blades become blunt.

[0038] The blade unit 01 has a support frame 02, which has an inner side and an outer side directed towards a shaving plane. The views in Fig. 1 and 2look at the back of the blade unit 01, so that the inside of the support frame 02 is visible. Several elongated blades 03 are arranged in the support frame 02, each with a cutting edge 04 running transversely to the shaving direction. In the example shown, five blades 03 are used as the main blades, so it is referred to as a 5-cutter. In modified embodiments, fewer or more blades can be arranged in the blade unit.

[0039] The support frame 02 has a base plate 06 comprising two opposing side sections 07. In the illustrated embodiment, the side sections 07 have rearwardly angled side shields 08, which laterally shield the interior of the blade unit 01. In modified embodiments, the side sections can be designed without the angled side shields. This results in increased flexibility of the base plate, allowing it to adapt better to uneven body surfaces.

[0040] Between the side sections 07 run several parallel supports 09, between each of which a free space 11 remains. Each support 09 comprises a head section 12 and a foot section 13 angled to the head section. One of the blades 03 is attached to the inside of the head section 12 of the associated support 09, so that the cutting edge 04 lies in the free space 11 between two adjacent supports 09 or, in the case of the foremost blade in the shaving direction, in the free space between its support and a blade guard 14, which extends in front of the foremost blade parallel to its cutting edge. The cutting edges 04 are directed towards the outside of the support frame 02 so that they come into contact with the hair to be cut during shaving. The cutting edge 04 of the foremost blade is preferably set back slightly inwards compared to the blade guard 14 in order to avoid shaving injuries.The subsequent blades preferably rise gradually in what is known as a protrusion, which can also be an underhang or a backhang (protrusion, exposure). Other arrangements, for example, with varying protrusion lengths, are also possible.

[0041] The rear side of the support frame 02 in the shaving direction is angled inward twice. This forms a rear protective plate 16, which simultaneously serves to hold a gliding strip 17. The gliding strip 17 is thus located behind the last blade 03 in the shaving direction. The upper side of the gliding strip 17 protrudes through a gliding strip recess 18 ( Fig. 3 ) in the base plate 06 to touch the skin during shaving.

[0042] The front side of the support frame 02, in the shaving direction, has a pre-tensioner recess 19 in which a skin pre-tensioning strip (also referred to as a foam edge) can be positioned (not shown). Furthermore, several fastening elements 21 are integrally formed in this front area of the support frame 02, which can be coupled to a handle and / or a housing unit (not shown) to support the blade unit 01.

[0043] At the rear end of the support frame 02, in the shaving direction, there is a trimmer blade recess 20 into which a trimmer blade (not shown) can be inserted if necessary. The cutting edge of the trimmer blade would then protrude slightly from the trimmer blade recess 20.

[0044] Fig.3shows a plan view of the base plate 06 of the support frame 02 before a bending process, which can comprise several bending steps. The base plate 06 is preferably made of metal, in particular of stainless steel. It can be seen that all the necessary recesses are made in the base plate 06 before bending, which then form the free spaces 11, the sliding strip recess 18 and the pretensioner recess 19. It is also clearly visible in this illustration that the free spaces 11, each beginning at the side sections 07 of the support frame 02, run in a stop section 22 at an acute angle to the cutting edge located in the free space 11. The axis of the free space between the adjacent supports 09 thus tilts in the stop section by, for example, ±45°. In addition, an incision 23 is made in each stop section 22 parallel to the cutting edge 04 of the blade 03 to be inserted, the function of which will be explained below.

[0045] Fig. 4shows a perspective detailed view of the carrier 09. During the bending process, the head section 12 and the foot section 13 are angled relative to each other along a bending line 24, so that they enclose an angle of, for example, between 90° and 160°. This bending primarily serves to increase the rigidity of the carrier 09, so that there is no bending in the longitudinal direction of the strip-shaped carrier 09 during shaving. At the stop section 22, a cutting edge stop 26 is bent out of the plane of the stop section 22 along the incision 23 in the manner of a projection. The essentially triangular cutting edge stop 26 is located on a section of the carrier 09 that runs at an acute angle to the cutting edge 04 and rises into the interior of the blade unit 01. The side edge of the cutting edge stop 26, which results from the notch 23, runs parallel to the cutting edge 04 of the blade 03 to be positioned there.

[0046] Fig. 5 shows a perspective detailed view of the carrier 09 with the blade 03 attached to it. It can be seen that the end of the cutting edge 04 abuts the cutting edge stop 26, whereby the position of the cutting edge 04 is precisely determined, regardless of the transverse dimension of the blade 03, which may be subject to manufacturing tolerances. This ensures that the cutting edge 04 of each individual blade 03 is located exactly at the desired height or at the desired distance from the shaving plane. The shaving plane can be viewed as the surface that touches the blade guard 14, which is located at the front in the shaving direction, and the glide strip 17, which is located at the rear in the shaving direction.

[0047] Fig. 6shows a side view of the carrier 09 with the blade 03 attached to it. It is clearly visible that the blade 03 is attached to the head section 12 on the inside of the carrier 09. The projection or elevation of the cutting edge stop 26 corresponds approximately to the thickness of the blade 03.

[0048] Fig. 7 shows a side sectional view of a second embodiment of the blade unit 01. Fig. 8shows a detailed view of this embodiment, although the blades have not been shown for reasons of clarity. In this case too, a total of five blades 03 are arranged, each on the inside of the head section 12 of the associated carrier 09, so that the cutting edge 04 lies in the free space 11. In this embodiment, the notched cutting edge stop is missing. In order to position the cutting edges of the five main blades precisely in the shaving plane or by the desired offset outside of this plane, a positioning recess 27 is provided in the base plate 06 of the carrier frame 02 in the area of the stop section 22.

[0049] Fig. 9shows a side sectional view of an assembly device 28 with the blade unit 01 mounted during the manufacturing process. The assembly device comprises several stops 29, each of which engages in the positioning recess 27 and against which the cutting edges of the individual blades are struck. Two positioning bollards 30, which engage in the still unfilled pretensioner recess 19, ensure basic alignment of the support frame 02 on the assembly device 28.

[0050] Fig. 10 shows a perspective view of a razor equipped with the blade unit 01 with a handle 31. It can be seen that the blade unit is attached directly to the handle 31 of the razor by means of its fastening elements.

[0051] The scope of the present invention is defined by the appended claims. Reference symbol

[0052] 01Blade unit 02Carrier frame 03Blades 04Cutting edge 05- 06Base plate 07Side sections 08Side guard 09Carrier 10- 11Clearance 12Carrier head section 13Carrier foot section 14Blade guard 15- 16Rear guard 17Glide strip 18Glide strip recess 19Pre-tensioner recess 20Trimmer blade recess 21Fasteners 22Stop section 23Notch 24Bend line 25- 26Cutting edge stop 27Positioning recess 28Mounting device 29Stop 30Positioning bollard 31Handle

Claims

1. Blade unit (01) for a wet razor comprising a support frame (02), which has an inner face and an outer face oriented towards a shaving plane and in which a plurality of elongate blades (03) are arranged, which respectively have a cutting edge (04) which extends transversely with respect to a shaving direction, wherein: - the support frame (02) has two opposing side portions (07), which are flat and extend transversely to the cutting edges (04) of the blades (03); - a plurality of mutually parallel supports (09) run between the side portions (07), between which an open space (11) respectively remains and which supports each have a head portion (12) and a thereto angled base portion (13); - one of the blades (03) is respectively mounted to the inside of the head portion (12) of one of the supports (09), so that the cutting edge (04) lies in the open space (11) and extends in the direction of the outside; - the open spaces (11) respectively run starting at the side portions (07) of the support frame (02) in a limit stop portion (22) at an angle to the cutting edge (04).

2. Blade unit (01) according to claim 1, characterized in that the support frame (02) is formed in one piece from a base plate (06), which is preferably made of metal and has been subjected to one or more bending steps.

3. Blade unit (01) according to any one of the claims 1 to 2, characterized in that the cutting edges (04) of the blades (03) respectively come in contact with a respective cutting edge limit stop (26) at their two ends in the associated limit stop portion (22), wherein the cutting edge limit stop (26) rises into the interior of the blade unit at a portion of the support (09) extending at an angle to the cutting edge (04).

4. Blade unit (01) according to any one of the claims 1 to 2, characterized in that a positioning recess (27) is provided in each of the limit stop portions (22), in which a stopper (29) of a mounting device (28) can engage during the assembly of the blade unit.

5. Blade unit (01) according to any one of the claims 1 to 4, characterized in that the cutting edge (04) located in the open space (11) protrudes beyond the head portion (12) of the support (09) by a predetermined projection dimension.

6. Blade unit (01) according to any one of the claims 1 to 5, characterized in that a slide strip recess (18) is mounted in the support frame (02) behind the blades (03) in the shaving direction, in which recess a slide strip (17) is mounted.

7. Blade unit (01) according to any one of the claims 1 to 6, characterized in that in the shaving direction, in front of the blades (03), a pretensioner recess (19), in which a skin pretensioning strip can be positioned, is fitted in the support frame (02).

8. Blade unit (01) according to any one of the claims 1 to 7, characterized in that in the shaving direction, at the rear end of the support frame (02), a trimmer blade recess (20) is arranged, in which a trimmer blade is arranged.

9. Blade unit (01) according to any one of the claims 1 to 8, characterized in that the blades (03) are welded to the respective head portion (12) of the support (09), preferably, in each case, by a plurality of laser welding points.

10. Blade unit (01) according to any one of claims 1 to 9, characterized in that fastening elements (21) are formed as one piece on the support frame (02), which can be coupled to a handle (31) and / or a housing unit.

11. Blade unit (01) according to claim 10, characterized in that the fastening elements (21) are formed as resilient tabs, hooks, detents.

12. Wet shaver comprising a handle (31) and a blade unit (01) directly or indirectly fastened thereto according to any one of claims 1 to 11.