Hair cutting device with a cutting length adjustment device

Abstract

Hair cutting device (100), comprising a blade arrangement (102) with a first cutting element (104) and a second cutting element (106) which is designed to be movable at least laterally relative to the first cutting element, a drive device which drives the blade arrangement (102), and a cutting length adjustment device which interacts with the first cutting element (104) or second cutting element (106) such that a longitudinal offset can be adjusted between the first cutting element (104) and the second cutting element (106), wherein the cutting length adjustment device has a lever (12) with a pre-tensioned detent lug (14) for adjusting the first or second cutting element and at least one retaining recess such that the detent lug (14) engages in the retaining recess, characterized in that the lever (12) further comprises a sliding sleeve (24) which, in a first position, holds the detent lug (14) against the Preload force holdsand in a second position releases the locking lug (14).

Description

Field of invention The invention relates to a hair cutting device with a cutting length adjustment device with a switching function. State of the art Hair cutting devices with a cutting length adjustment mechanism are known in the prior art. Typically, a hair cutting device has a blade arrangement with two cutting elements, a first of which is longitudinally displaceable for adjusting the cutting length and is fixed to the rest of the hair cutting device during the cutting process, and a second of which is arranged to oscillate laterally relative to the first and is used to cut the hair during the cutting process. Frequently, cutting elements with comb-like cutting edges are used, in which case the first cutting element is designed as a so-called shearing comb and comes into contact with the skin of the person or animal being treated, or the user. The second cutting element is then designed as a so-called shearing blade.Each cutting element has a series of spaced-apart teeth, which are generally arranged at regular intervals. Such a blade assembly can be designed to allow for different cutting lengths. The cutting length of such an adjustable blade assembly is adjusted by longitudinally offsetting the two cutting elements relative to each other. In removable / replaceable blade assemblies, the second, laterally movable cutting element is usually offset longitudinally, while in blade assemblies permanently attached to the hair clipper, the first cutting element is usually offset longitudinally. Solutions for adjusting the cutting length are known from the prior art, allowing for either stepless or incremental adjustment. Both variants occur with roughly equal frequency, although one or the other is usually preferred depending on the user. This leads to a situation, particularly in hair salons with multiple hairdressers, where both stepless and incrementally adjustable hair cutting devices are present, although most of these variants are not in use. As a result, these salons experience low machine efficiency, which in turn reduces overall profitability. Solutions known from the state of the art are therefore not very economical, inflexible and often do not offer the optimal adjustment options. DE 628 752 A discloses a hair cutting machine in which, for changing the cutting length of the hair, the cutting blade combs are adjustable relative to each other in the cutting direction, wherein a lower comb arranged between the two combs, which is fixedly connected to the handle in guides, is movable forwards and backwards by means of a manually operated adjusting element (e.g., an operating lever that can be operated continuously or in detents) for adjusting the upper comb, and which has transverse guides for the upper cutting comb which is connected to the drive. US Patent 2 006 493 A discloses a hair clipper with a comb plate and a holder on which the comb plate is slidably mounted, the combination with the holder comprising a transversely extending shaft which is mounted in the holder above the comb plate and is provided with a crank arm which is in operative connection with the comb plate in order to adjust it, and another arm which is connected to the crank shaft and extends along one side of the holder to provide a device which enables the adjustment of the comb plate during operation of the hair clipper. The subsequently published WO 2024 / 100054 A1 relates to a hair cutting device comprising a blade assembly with a first cutting element and a second, movable cutting element, a drive device for driving the blade assembly, a cutting length adjustment device which interacts with the second cutting element in such a way that a length offset between the first cutting element and the second cutting element can be adjusted, and a selector device with which the cutting length adjustment device can be adjusted between at least one first length adjustment mode and at least one second length adjustment mode, wherein in the first length adjustment mode the length offset can be adjusted stepwise or continuously and in the second length adjustment mode the length offset can be adjusted stepwise. DE 10 2009 015 276 A1 discloses a hair clipper with an interchangeable cutting set comprising at least one zigzag comb and a cutting blade which can be driven by a drive in an oscillating manner essentially parallel to the front edge of the zigzag comb, and a cutting length adjustment mechanism comprising at least one actuating element which is pivotally connected to a housing of the hair clipper and which acts on the cutting set, so that a relative displacement in the longitudinal direction between the zigzag comb and the cutting blade is possible, wherein a nose is fixedly arranged on the actuating element, wherein a receptacle for the nose is slidably mounted on the cutting set. DE 10 2017 110 525 A1 discloses a hair clipper comprising a housing with a first and a second longitudinal side and a bottom and top extending between them, a lower blade, an upper blade adjustable relative to the lower blade and transversely to the cutting direction by means of a drive located in the housing, an actuating element projecting from the first longitudinal side, and an adjusting element operable via this actuating element, by means of which the lower blade can be adjusted relative to the upper blade in the cutting direction. The actuating element can be connected to the adjusting element directly or indirectly via both the first and the second longitudinal side of the housing. Description of the invention The object of the present invention is to provide a hair cutting device with a cutting length adjustment device in which it is easy to switch back and forth between a stepless and a stepped adjustment mode. This object is achieved with a hair cutting device according to claim 1. A hair cutting device according to the invention comprises a blade arrangement with a first cutting element and a second cutting element, which is designed to be movable at least laterally relative to the first cutting element, a drive device that drives the blade arrangement, and a cutting length adjustment device that interacts with the first cutting element in such a way that a longitudinal offset can be adjusted between the first cutting element and the second cutting element, wherein the cutting length adjustment device has a lever with a pre-tensioned detent for adjusting the first movable cutting element and at least one retaining recess, such that the detent engages in the retaining recess, making it difficult, in particular preventing, the lever from moving out of the retaining recess, wherein the lever further comprises a sliding sleeve that, in a first position, holds the detent against the pre-tension force.and in a second position releases the locking tab. Because the cutting length adjustment device is located outside the hair clipper and a switching function is provided on the cutting length adjustment device, switching between modes is simple. Furthermore, no complicated mechanics are required inside the hair clipper, since the mode switching device, which includes the locking tab and retaining recess, is located on the cutting length adjustment device outside the hair clipper. The sliding sleeve preferably surrounds the lever at least partially. This ensures a secure hold of the sliding sleeve on the lever. The sliding sleeve can be completely closed, thus enclosing the lever entirely. Preferably, however, the sliding sleeve completely covers the lever on the side of the locking lug and engages in a groove on the upper and lower sides of the lever. This allows the sliding sleeve to interact securely with the locking lug and simultaneously ensures that the sleeve remains accessible. If the lever has a rectangular or square cross-section, the sleeve extends, in particular, over 2 / 3 of the upper and / or lower sides of the lever. The retaining projection is preferably conical in shape and further features a hemispherical end, particularly at its tip. The end may have a flat section. This allows it to slide more easily into the retaining recess, and also enables the sliding sleeve to move the locking lug against the preload force without the need for tools. The sliding sleeve preferably has a recess on the side of the locking lug. In particular, the recess tapers from one end of the locking lug to the other end, such that the contact points of the recess with the locking lug approach each other from the first position of the sliding sleeve to the second position. This allows the locking lug to be moved even more easily against the preload force. The recess in the sliding sleeve is preferably circular at one end to provide a seat for the locking lug. This prevents accidental switching between the stepless and stepped adjustment modes, particularly if the locking lug has a conical shape. The recess at the entry end is wider than the diameter of the locking lug, so that the locking lug does not contact the sliding sleeve in the second position. Alternatively, the sliding sleeve can be spaced away from the locking lug in the second position, requiring the sleeve to be pushed towards the first position to make contact. Preferably, however, the sliding sleeve acts as a stop for the locking lug, preventing the spring from pushing the locking lug out of the opening. In other words, the sliding sleeve is at least partially positioned over the opening. The sliding sleeve preferably projects beyond the surface of the lever on at least one side, or is at least partially protruding. This ensures easier movement of the sliding sleeve, as a user can reliably reach it with, for example, their fingers. The lever is at least partially flat on the side facing the hair cutting device, and in particular completely flat. This ensures that the locking lug can securely engage in the retaining recess on the hair cutting device. Preferably, the sliding sleeve has a projection that is angled, for example by more than 60° or by 90°. This makes it easier to grip and move the sliding sleeve. Brief description of the characters Fig. 1 shows a hair cutting device with an adjustment lever in a top view; Fig. 2 shows an isometric exploded view of a lever of the cutting length adjustment device; Fig. 3a shows the lever of the cutting length adjustment device in a side view with a sliding sleeve in a first position; Fig. 3b shows the lever of the cutting length adjustment device in a sectional view with a sliding sleeve in a first position; Fig. 4a shows the lever of the cutting length adjustment device in a side view with a sliding sleeve in a second position; and Fig. 4b shows the lever of the cutting length adjustment device in a sectional view with a sliding sleeve in a second position. Description of preferred embodiments Figure 1 shows a hair cutting device 100 with a blade assembly 102 comprising a first cutting element 104 and a second, laterally movable cutting element 106, which is laterally movable relative to the first cutting element 104. The blade assembly 102 is driven by a drive device located in the housing of the hair cutting device 100. The cutting length adjustment device 10 interacts with the first cutting element 104 or the second cutting element 106 such that a longitudinal offset between the cutting elements 104 and 106 can be adjusted. This means that when the lever 12 is moved forward or backward, the first or second cutting element is moved backward or forward (see arrow A), thus shortening or lengthening the cutting length of the hair cutting device 100. Such a mechanism is known in the prior art.The cutting length is adjusted via a lever 10, which is usually provided on the side of the hair cutting device 100. Figures 2 to 4b show the lever of the cutting length adjustment device 10 in different views. The cross-section of the lever 12 is preferably rectangular or square with rounded edges. In particular, the side facing the hair cutting device 100 is designed to be as flat as possible. The lever 12 has a locking lug 14 and a sliding sleeve 24. The lever 12 also has a step 13, so that the pivot section 22, about which the lever 12 rotates on the hair cutting device 100, is slightly recessed relative to the lever arm in the top view. The pivot section 22 is then preferably connected to the adjustment mechanism inside the hair cutting device 100 via a pin 21, so that rotating the lever 12 moves the first or second cutting element 104, 106 in the longitudinal direction A (Fig. 1). The hair clipper 100 has lateral recesses 110 with which the lever 12 interacts, as described later. Fig. 2 shows the lever 10 in an isometric exploded view, with the locking lug 14 arranged on the inside, facing the hair-cutting device. Furthermore, the lever 12 also has a sliding sleeve 24 which interacts with the locking lug 14. The sliding sleeve 24 can be formed completely around the lever, but preferably, as shown in the figures, it only completely covers the inner surface and engages in an upper groove 18 and a lower groove on the upper and lower surfaces of the lever 12, which guide the sliding sleeve 24 on the lever 12. The sliding sleeve is preferably U-shaped (as shown here), with inwardly inclined projections at the ends that engage in the grooves 18. One or both of these grooves 18 can serve as a stop for the sliding sleeve 24, thus limiting its movement on the lever 10. The sliding sleeve 24 projects beyond the surface of the lever, particularly on the upper and lower surfaces, so that it can be moved more easily by the user's fingers. The edges 26 of the sliding sleeve 24 parallel to the lever are preferably rounded on the outside.In particular, the edges 28, which run perpendicular to the lever, are formed without rounding, with a clear 90° edge, so that a user can grip and operate the sleeve more securely. On the inside of the sliding sleeve 24, it rests against the lever 12, for example, with a small amount of play. On the inside, the sliding sleeve 24 has a recess 30, which will be described in more detail below. The sliding sleeve 24 may have a rough texture on its surface to improve grip and facilitate its movement. The locking lug 14 is pre-tensioned, for example, by a spring element, shown in the figures as a coil spring, or by a repelling magnetic device, each arranged below the locking lug 14, so that the locking lug 14 is pressed out of the lever. The locking lug 14 is preferably at least partially conical and arranged in a circular opening 20 in the lever 12. To prevent the locking lug 14 from falling out of the lever 12, the opening 20 may have an undercut below its surface. In the illustrated embodiment, the sliding sleeve is positioned in the second position with a stop such that the sliding sleeve prevents the locking lug 14 from falling out. A further recess, which has a smaller diameter than the opening 20 and serves to support a spring 17, may be arranged at the bottom of the opening 20. The conical section of the locking lug 14 is preferably the section projecting from the lever 12.The detent lug 14 shown has a circular cross-section, but other basic shapes such as squares, triangles, rectangles, or other polygons are also usable. The detent lug tip 16 is preferably provided with a radius and, for example, is designed as a hemisphere. More preferably, the tip can be flattened. The surface at the tip is, in particular, a flat surface with a radius of 0.5 to 3 mm. A guide projection 15 is preferably formed on the underside of the detent lug, which is received by the spring 17 and ensures that the spring 17 and the detent lug 14 are aligned, in particular concentrically. The detent lug 14 is then pressed by the spring into the recesses 110, so that the user receives tactile feedback about the setting of the lever 12. Preferably, no elements are provided on the outside of the lever handle. The end of the lever 12 may be rounded. A through-hole 23 is preferably provided in the rotating section 22, into which a pin of the hair clipper 100 can be inserted, around which the lever 12 can rotate. Figures 3a and 4a show the lever in a top view. Figures 3b and 4b show a longitudinal section of the lever 12 from the same direction. In Figures 3a and 3b, the sliding sleeve 24 of the lever is in a first position in which the locking lug 14 is held in a retracted position by the sliding sleeve 24. This can be achieved, for example, by the locking lug 14 having a slot into which the sliding sleeve 24 can be inserted and which holds the locking lug 14. Preferably, the sliding sleeve 24 has a recess 30. This recess 30 is designed in particular such that the locking lug 14 can not only be held in the first retracted position, but is also forced from the second position, in which the locking lug 14 protrudes, into the first position, in which the locking lug 14 is retracted. For this purpose, the recess 30 can, for example, be at least partially tapered, i.e., the edges 32 of the recess approach each other. The retaining part in which the locking lug 14 is then held is preferably rectangular or square, such that the end 31 of the recess 30 runs parallel to the edges 28. A projection 19 is arranged at the end of the sliding sleeve 24 facing the axis of rotation, extending over the sides of the sliding sleeve 24. In particular, this projection 19 extends upwards, preferably at a 90° angle to the surface of the sliding sleeve. The projection 19 serves to facilitate gripping with a finger or thumb. At the end of the recess 30, a circular segment can alternatively be provided that has a wider diameter than the distance between the edges 31 at their narrowest point. The locking lug 14 then engages in the circular segment 34 and is held there in a retracted position, preventing it from sliding back into the tapered section on its own. The circular segment 34 therefore acts as a seat for the locking lug 14. The entrance side of the recess 30 is preferably larger than the largest diameter of the locking lug 14 protruding from the lever. In the second position of the sliding sleeve Figures 4a and 4b show the sliding sleeve 24 of the lever in a second position, in which the sliding sleeve 24 releases the locking lug 14. Figure 4b shows that the sliding sleeve 24 is not completely removed from the locking lug 14, but rather protrudes beyond the edge of the opening 20 and thus serves as a stop for the locking lug 14. When the sliding sleeve 24 is then pushed from the second to the first position, the recess edges 32 contact the side surfaces of the conically shaped locking lug 14. Due to the tapered design, the locking lug 14 is then pressed downwards as the contact points approach the recess 30. In the first position of the sliding sleeve 24, the lever 12 is infinitely adjustable. In this position, the locking lug 14 is retracted by the sliding sleeve 24, and the tip 16 of the locking lug 14 is lifted from the hair clipper 100, so that the locking lug 14 cannot engage in the recess 110 for the locking lug 14. In the second position of the sliding sleeve 24, the locking lug 14 protrudes further from the lever 12 due to the spring force of the spring 17 and the absence of a stop on the sliding sleeve 24, so that the tip 16 of the locking lug 14 contacts the hair clipper 100 and engages in the recess 110 for the locking lug 14. This allows the user to feel precisely when the locking lug 14 engages or slides out of the recess 110. Reference symbol list 10 Cutting length adjustment device 12 Lever 13 Step 14 Detent lug 15 Guide projection 16 Detent lug tip 17 Spring 18 Upper groove 19 Projection 20 Opening 21 Pin 22 Rotating section 23 Through hole 24 Sliding sleeve 26 Rounded edges 28 Edges 30 Recess 31 End of recess 32 Recess edges 34 Circular recess 100 Hair cutting device 102 Blade assembly 104 First cutting element 106 Second cutting element 110 Recesses for detent lug

Claims

Hair cutting device (100), comprising a blade arrangement (102) with a first cutting element (104) and a second cutting element (106) which is designed to be movable at least laterally relative to the first cutting element, a drive device which drives the blade arrangement (102), and a cutting length adjustment device which interacts with the first cutting element (104) or second cutting element (106) such that a longitudinal offset can be adjusted between the first cutting element (104) and the second cutting element (106), wherein the cutting length adjustment device has a lever (12) with a pre-tensioned detent lug (14) for adjusting the first or second cutting element and at least one retaining recess such that the detent lug (14) engages in the retaining recess, characterized in that the lever (12) further comprises a sliding sleeve (24) which, in a first position, holds the detent lug (14) against the Preload force holdsand in a second position releases the locking lug (14). Hair cutting device (100) according to claim 1, wherein the sliding sleeve (24) at least partially surrounds the lever (12). Hair cutting device (100) according to one of the preceding claims, wherein the sliding sleeve (24) engages in a groove (18) of the lever (12) on the upper and lower sides of the lever. Hair cutting device (100) according to one of the preceding claims, wherein the locking lug (14) is at least partially conical in shape. Hair cutting device (100) according to one of the preceding claims, wherein the sliding sleeve (24) has a recess (30) on the side of the locking lug (14). Hair cutting device (100) according to claim 5, wherein the recess (30) tapers from one inlet end to the other end. Hair cutting device (100) according to claim 5 or 6, wherein the recess at one end is circular in order to provide a seat (34) for the locking lug (14). Hair cutting device (100) according to one of claims 5 to 7, wherein the recess (30) at the inlet end is larger than the diameter of the locking lug (149) protruding from the lever (12). Hair cutting device (100) according to one of claims 5 to 8, wherein the sliding sleeve (24) serves as a stop for the locking lug (14) in the second position, so that the locking lug (14) is held by the sliding sleeve in the opening (20). Hair cutting device (100) according to one of the preceding claims, wherein the sliding sleeve (24) projects beyond the surface of the lever (12) on at least one side of the lever (12). Hair cutting device (100) according to one of the preceding claims, wherein the lever (12) is at least partially flat on the side facing the hair cutting device (100).

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