Cutting head for a brushcutter

Description

[0001] The invention relates to a cutting head of the type specified in the preamble of claim 1.

[0002] Cutting heads for brushcutters are known that consist of a base body comprising two base body parts. During operation of the brushcutter, the base body is driven to rotate about a pivot axis. At least one cutting tool is arranged between the base body parts, with a bearing pin in the base body on which the cutting tool is held. To assemble the cutting head, the cutting tool is threaded onto the bearing pin, and then the base body parts are attached to the output shaft of the brushcutter. A disadvantage of such cutting heads is that the numerous individual parts significantly complicate assembly. Cutting heads of this type are known from US Patent 2008 / 271424 A1.

[0003] The invention is based on the objective of further developing a cutting head of the generic type in such a way that simple assembly and disassembly of the cutting head as well as simple attachment of the cutting head to the output shaft of the brushcutter is enabled.

[0004] The problem is solved by a cutting head according to claim 1.

[0005] The cutting head according to the invention for a brushcutter comprises a split base body. The base body, in turn, comprises an upper base body part and a lower base body part. The upper base body part is the part that, when the cutting head is attached, rests against the brushcutter with its top surface. The lower base body part is the part that, when the cutting head is attached to the brushcutter, faces the ground during normal operation of the brushcutter. A screw element is arranged on the lower base body. This screw element serves to attach the base body to an output shaft of a brushcutter. At least one receptacle for attaching a cutting tool is provided between the upper base body part and the lower base body part. The cutting tool is arranged axially, i.e., in the direction of the axis of rotation of the base body, between the upper base body part and the lower base body part.The base body can be rotated around its axis of rotation when operating a brushcutter. The upper and lower base body sections are held together by a releasable snap connection.

[0006] The snap-fit ​​connection allows the operator of the brushcutter to connect the upper and lower body sections while holding the cutting tool in place. This connects the upper and lower body sections, forming a single unit with the cutting tool that can be screwed onto the brushcutter's output shaft. This eliminates the need for the operator to individually mount the various cutting head sections onto the output shaft. Furthermore, the snap-fit ​​connection prevents the cutting head sections from accidentally coming apart when disassembling.

[0007] It is advantageously provided that the snap connection has a distance measured in the radial direction to the axis of rotation which is at most 40%, in particular at most 30%, preferably at most 25% of the diameter of the cutting head.

[0008] It is advantageously provided that the mounting has a bearing axis extending in the direction of the axis of rotation, wherein the bearing axis is spaced further from the axis of rotation, and the distance between the bearing axis and the axis of rotation is greater than the distance between the snap connection and the axis of rotation. The snap connection is thus located inside the cutting head and is therefore protected. Due to the snap connection's proximity to the axis of rotation, it does not restrict the pivoting movement of the cutting tools. If a cutting tool encounters a solid obstacle during operation, it can pivot far back against the direction of rotation of the cutting head without striking the snap connection.

[0009] The snap connection preferably comprises at least one gripping hook and, in particular, at least one retaining contour operatively connected to the gripping hook. The gripping hook is preferably located on the upper base body part, and the at least one retaining contour is preferably located on the lower base body part. When the upper and lower base body parts are brought together, the gripping hook contacts the retaining contour and is deflected radially to the axis of rotation. For this purpose, the gripping hook is preferably flexible in the direction radial to the axis of rotation. Once the upper and lower base body parts are sufficiently pushed together, the gripping hook of the snap connection engages behind the retaining contour. The at least one gripping hook preferably has a hook head designed to engage behind the at least one retaining contour.Once the snap connection engages, the upper and lower base parts are held together in the direction of the cutting head's axis of rotation. The hook head is preferably directed outwards, radially away from the axis of rotation. This ensures that, during operation of the brushcutter, the gripping hook is pressed outwards against the retaining contour by centrifugal forces. As a result, the shape of the gripping hook, or rather its preload against the retaining contour, is maintained even over extended periods of use of the cutting head.

[0010] The hook head is preferably designed such that the snap connection engages when the upper and lower base body parts are pressed together and disengages when the base body parts are pulled apart. To engage the snap connection, the base body parts must be pushed together in the direction of the axis of rotation; to disengage the snap connection, the base body parts must be pulled apart in the opposite direction. The forces required to engage and disengage the snap connection result from the geometries of the hook head and the retaining contour. The spring action of the gripping hooks also influences the engagement and disengagement forces of the snap connection. By adapting the geometries of the hook head and the retaining contour, the engagement and disengagement forces of the snap connection can be adjusted to meet the requirements of the cutting head.The snap connection preferably has two, and in particular three or more, gripping hooks with corresponding retaining contours. If several gripping hooks and retaining contours are provided, they are preferably arranged at uniform angular intervals around the axis of rotation of the cutting head.

[0011] Preferably, a guide contour is provided on one of the two base body parts, and a guide groove extending in the direction of the axis of rotation and cooperating with the guide contour is provided on the other base body part. This alignment of the upper and lower base body parts is achieved by means of the guide contour and the guide groove in the circumferential direction of the axis of rotation. Only when the upper and lower base body parts are aligned such that the guide contour can engage in the guide groove is it possible for the base body parts to come together and consequently for the snap connection to engage. Otherwise, the guide contour blocks the coming together of the base body parts. Therefore, the snap connection is designed such that it can only engage when the upper and lower base body parts are aligned relative to each other via the guide contour and the guide groove.This allows the operator of the brushcutter to easily and correctly mount the cutting head. In accordance with the Poka-Yoke principle, user errors during cutting head assembly are eliminated.

[0012] It is advantageously provided that torques in the circumferential direction can be transmitted between the upper and lower base body parts via the interference contour and the guide groove. This protects the snap connection from torques acting on the base body parts during the assembly of the cutting head, as these torques are absorbed by the interference contour and the guide groove. The snap connection is not subjected to torque. Preferably, the base body comprises at least two or more interference contours with corresponding guide grooves.

[0013] The mounting for a cutting tool of the cutting head is preferably designed as a bearing pin. A cutting tool can preferably be mounted on the base body via the bearing pin. The bearing pin is designed such that the cutting tool is pivotably held on the bearing pin. The bearing pin is preferably attached to the upper or lower base body part on one side. This allows for easy assembly and disassembly of the base body parts, particularly compared to cutting heads whose base body parts are also screwed together via the bearing pins. To separate or join the upper and lower base body parts, only the snap connections need to be released or engaged. The bearing pin is preferably attached to the upper base body part.

[0014] It is advantageously provided that the screw element is arranged in a rotationally fixed manner on the lower base part. When attaching the cutting head to the brushcutter, the cutting head is preferably screwed onto the brushcutter's output shaft as a pre-assembled unit via the screw element. The screw element clamps the lower base part against the upper base part, with the upper base part being supported at its end face by the brushcutter. The screw element can be a separate component from the lower base part or a thread integrated into the lower base part. This ensures that the screw element, together with the lower base part, tightens against the upper base part on the output shaft.

[0015] A cutting tool is preferably pivotably mounted on at least one of the cutting head's mounting points. The outer section of the cutting tool, which protrudes from the base of the cutting head, can be used to cut grass, brush, or similar material.

[0016] Further features of the invention will become apparent from the description and the drawing, in which an embodiment of the invention, described in detail below, is illustrated. The drawing shows: Fig. 1 shows a schematic side view of a brushcutter with a cutting head, Fig. 2 shows a perspective view of the cutting head with cutting tool according to the invention, Fig. 3 shows a side view of the cutting head according to Fig. 2 , Fig. 4 in a view from below the cutting head towards Fig. 2 , Fig. 5 in a top view the cutting head after Fig. 2 , Fig. 6 in a sectional view the cutting head along arrows VI to Fig. 5 , Fig. 7 in a sectional view the cutting head along arrows VII to Fig. 5 , Fig. 8 in a sectional view the cutting head along arrows VIII to Fig. 7 , Fig. 9 in a sectional view the cutting head along arrows IX to Fig. 5 , Fig. 10 in a sectional view from above the cutting head with cutting tools swung out Fig. 2 Fig. 11 shows the upper base body part of the cutting head in a perspective view, Fig. 12 shows the upper base body part of the cutting head in a bottom view, and Fig. 13 shows the upper base body part in a sectional view along arrows XIII. Fig. 12 Fig. 14 shows the lower base body part of the cutting head in a perspective view, Fig. 15 shows the lower base body part of the cutting head in a top view, and Fig. 16 shows the lower base body part in a sectional view along arrows XVI. Fig. 15 .

[0017] In Fig. 1 Figure 100 shows a brush cutter of the type 100 in a perspective side view. A cutting head 10 is provided at a first, lower end 5 of a guide tube 6, at the second, upper end 105 of which a drive motor 101 is held. The drive motor 101 drives a connecting shaft 107, which is advantageously designed as a flexible shaft 7 and follows the curvature of the guide tube 6. In the area of ​​the upper end section of the guide tube 6, an operating handle 103 is provided, which is penetrated by the guide tube 6. Adjacent to the operating handle 103, a round handle 104 is mounted on the guide tube 6.

[0018] The curvature of the guide tube 6 determines the working position of the cutting head 10 relative to the ground, eliminating the need for a bevel gear. Alternatively, the cutting head 10 can also be driven via a bevel gear. The cutting head 10 is advantageously positioned as close as possible to the end 5 of the guide tube 6 and is preferably equipped with a grass guard 106 to prevent grass from becoming entangled in the drive train. Another arrangement of the drive motor 101, particularly at the lower end 105 of the guide tube 6, may also be advantageous.

[0019] As in the Fig. 2 bis 4 As shown, the cutting head 10 comprises a base body 11, which is formed from an upper base body part 12 and a lower base body part 13. When the cutting head 10 is attached to the working tool 100, the upper base body part 12 rests against the working tool 100. In the working tool 100's normal operating position, the lower base body part 13 faces the ground 4. At least one cutting tool 14 is held between the upper base body part 12 and the lower base body part 13. A screw element is provided on the base body 11 for attaching the cutting head 10 to an output shaft 18 of the working tool 100. Fig. 4 ) arranged. The cutting head 10, in particular the base body 11, is driven to rotate about a rotary axis 17 during operation of the working device 100.

[0020] As in the Fig. 2 bis 4 As shown, the cutting head 10 in the exemplary embodiment comprises two cutting tools 14, each held on a receptacle 15. In the preferred embodiment, the cutting tools 14 are designed as cutting blades. The cutting head 10 preferably has further receptacles 45 for attaching cutting threads. Thus, the cutting head 10 can be operated with cutting blades and / or with cutting threads. The receptacles 15 are designed as bearing pins 16 ( Fig. 6 ), whereby a cutting tool 14 is pivotably held on the bearing pin 16 about its bearing axis 32. The bearing axis 32 of the bearing pin 16 runs parallel to the axis of rotation 17. In an alternative embodiment of the cutting head 10, three or more cutting tools 14 can also be provided. To avoid imbalance of the cutting head 10, the receptacles 15 for the cutting tools 14 are arranged at a uniform angular distance β about the axis of rotation 17 of the cutting head 10. Thus, the angular distance β between the bearing axes 32 of adjacent receptacles 15 is preferably constant. Accordingly, in the present embodiment of the cutting head with two receptacles 15, the angular distance β is 180°.

[0021] As in Fig. 4 and 6As shown, the screw element 19 is arranged on the lower base body part 13. In this embodiment, the screw element 19 is designed as a nut. It is located within the lower base body part 13. The screw element 19 is hexagonal and engages in a corresponding counter-contour of the lower base body part 13, thus preventing rotation relative to the base body part 13. The inertia of the lower base body part 13 ensures that the screw element 19 tightens during operation of the cutting head 10. In this embodiment, the screw element 19 is made of a metal material, while the lower base body part 13 is made of plastic. The screw element 19 is pressed into the lower base body part 13 in this embodiment, but as an alternative fastening method, it can be overmolded with plastic.In an alternative embodiment of the cutting head 10, it may be advantageous to design the screw element 19 as a captive nut that is rotatable relative to the lower base body part. When attaching the cutting head 10, it is secured to the surface by means of the screw element 19. Fig. 3 Schematically depicted output shaft 18 screwed on.

[0022] In Fig. 5 The cutting head 10 is shown in a top view to indicate the different sectional views.

[0023] The representation according Fig. 6 Figure 1 shows a cross-section of the cutting head 10 with cutting tool 14 through the receptacles 15, which are designed as bearing pins 16. In the preferred embodiment of the cutting head 10, the bearing pins 16 are attached to the upper base body part 12. In an alternative embodiment, it may be advantageous to attach the bearing pins 16 to the lower base body part 13. The bearing pins 16 are attached on one side either to the upper base body part 12 or to the lower base body part 13. The bearing pin 16 has a threaded section 20 and a retaining section 21. The bearing pin 16 is screwed with its threaded section 20 into a retaining thread 22 provided in the upper base body part 12. In the exemplary embodiment, the retaining thread 22 is formed by a nut overmolded with plastic in the upper base body part 12. Alternatively, the retaining thread 22 can be pressed into the upper base body part 12.In the exemplary embodiment, the retaining thread 22 is knurled circumferentially for improved force transmission. The upper base body part 12 includes an opening 23 that extends approximately coaxially to the bearing axis 32 of the bearing bolt 16 to the upper surface 30 of the upper base body part 12 facing the working tool 100. The opening 23 serves to prevent material build-up during overmolding of the retaining thread 22 and prevents plastic from penetrating the internal thread of the retaining thread 22. The bearing bolt 16 is screwed into the retaining thread 22 via the lower surface 31 of the upper base body part 12, which faces away from the upper surface 30. The upper base body part 12 and the lower base body part 13 are not axially held together by the bearing bolt 16. Pulling the two base body parts 12 and 13 apart does not require any modification to the bearing bolt 16.

[0024] An independent inventive concept of the present cutting head 10 consists in the fact that, as in Fig. 6 As shown, a metal support plate 24 is provided, which is attached to the underside 31 of the upper base part 12 facing the lower base part 13. In the exemplary embodiment, the support plate 24 is formed in one piece and has a main opening for the partial passage of the lower base part 13. The support plate 24 also has a further opening for each bearing bolt 16, through which the respective bearing bolt 16 extends. The support plate 24 serves to support the bearing bolt 16 against the upper base part 12. A support ring 25 is provided between a first shaft shoulder 38 of the bearing bolt 16 and the support plate 24. When the bearing bolt 16 is tightened via the retaining thread 22, the bearing bolt 16 is clamped against the support plate 24 via the first shaft shoulder 38 and the support ring 25. The forces are introduced into the upper base body part 12 via the support plate 24.The metal construction of the support plate 24 ensures high support forces. Because all bearing bolts 16 are supported by the same support plate 24, some of the forces occurring during operation can be mutually compensated. This relieves the upper base body part 12 of stress.

[0025] As in Fig. 6 As shown, a bearing sleeve 26 is provided on the retaining section 21 of the bearing bolt 16, on which the cutting tool 14 is held. The cutting tool 14 is thus pivotable about the bearing axis 32 of the bearing bolt 16. The bearing axis 32 of the bearing bolt 16 runs parallel to the axis of rotation 17 of the cutting head 10. The bearing sleeve 26 is arranged to float between the support ring 25 and a second shaft shoulder 39 of the bearing bolt 16. The bearing sleeve 26 is preferably lubricated and made of sintered metal, which reduces the frictional forces between the cutting tool 14 and the bearing bolt 16. The heat generated during pivoting between the bearing sleeve 26 and the cutting tool 14 is transferred to the upper base body part 12 via the support plate 24.

[0026] The cutting tool 14 is pivotally held at one end in a pivot gap 28 of the cutting head 10 on the bearing sleeve 26 and protrudes from the pivot gap 28 at the other end. The pivot gap 28 is bounded by the underside 31 of the upper base body part 12 and by the upper side 43 of the lower base body part 13 facing the underside 31. When the cutting head 10 is mounted, the bearing pin 16 extends over the entire height of the pivot gap 28 in the direction of the axis of rotation 17 and projects into a pin opening 27 of the lower base body part 13 provided for the bearing pin 16. The bearing pins 16, when inserted into the pin openings 27, are also supported by the lower base body part 13.

[0027] As in Fig. 6 As shown, the upper base body part 12 has a through-opening 46 extending coaxially to the axis of rotation 17 for inserting the output shaft 18. In the exemplary embodiment of the cutting head 10, no positive locking is provided between the output shaft 18 and the upper base body part 12. In an alternative embodiment, a positive locking between the output shaft 18 and the upper base body part 12 can also be provided. In such an embodiment, however, the snap connection 1 must be rotatable on the retaining contour 4 in order to allow the lower base body part 13 to be rotated onto the output shaft 18. If only the screw element 19 is rotatable relative to the lower base body part 13, a rotatable snap connection 1 can be omitted.

[0028] The lower base body part 13 is divided radially with respect to the axis of rotation 17 into an inner region 33 and an outer region 34. The inner region 33 of the lower base body part 13 is designed as a dome 35, which extends into a central opening 36 of the upper base body part 12. The central opening 36 is specifically cup-shaped and extends around the through-opening 46. When the cutting head 10 is mounted, the dome 35, with its end face 47 facing the underside 31 of the upper base body part 12, contacts the upper base body part 12 at the end face 50 of the central opening 36. The end face 47 is part of the upper surface 43 of the lower base body part 13. The outer surface 34 of the lower base body part 13 serves primarily to attach the cutting tool 14 to the receptacles 15 and to form the pivot gap 28 between the upper base body part 12 and the lower base body part 13.In the preferred embodiment, the dome 35 of the lower base body part 13 has a diameter e measured radially to the axis of rotation 17, which in particular corresponds to at most 50% of the diameter d of the cutting head 10 measured radially to the axis of rotation 17. In an alternative embodiment of the cutting head 10, a dome with a larger diameter e may also be advantageous. The screw element 19 is held in the dome 35 of the lower base body part 13, in particular in a rotationally fixed manner.

[0029] As in the Fig. 7 , 8 , 13 , 16As shown, the cutting head 10 comprises a releasable snap connection 1. The snap connection 1 includes at least one gripping hook 2 and at least one retaining contour 4. The gripping hook 2 is preferably flexible in a radial direction away from the axis of rotation 17. The at least one gripping hook 2 is formed on the upper base body part 12 and extends into the central opening 36 of the upper base body part 12. A hook head 3 is formed at the end of the gripping hook 2 facing the lower base body part 13. The retaining contour 4 is formed on the lower base body part 13, in particular on the dome 35 of the lower base body part 13. The snap connection 1 is formed between the facing end faces 47, 50 of the base body parts 12, 13, i.e., the underside 31 of the upper base body part 12 and the top side 43 of the lower base body part 13.The gripping hooks 2 are protected in the pot-shaped central opening 36 of the upper base body part 12.

[0030] When mounting the cutting head 10, the upper base body part 12 and the lower base body part 13 are pushed together such that the gripping hook 2 engages in a retaining opening 8 on the dome 35 and the gripping hook 2 and the retaining contour 4 are in operative contact. The gripping hook 2 then engages with the retaining contour 4. The gripping hook 2 engages behind the retaining contour 4 with its hook head 3, causing the snap connection 1 to engage. The upper base body part 12 and the lower base body part 13 are connected by means of the snap connection 1. In the engaged position, the snap connection 1 exerts a holding force between the upper base body part 12 and the lower base body part 13, which acts essentially in the direction of the axis of rotation 17.

[0031] To release the snap connection 1, the upper base body part 12 and the lower base body part 13 must be pulled apart in the direction of the axis of rotation 17. Only the holding force of the snap connection 1 needs to be overcome. The holding head 3 has a contact surface 9 that establishes the operative connection with the holding contour 4. The contact surface 9 is oriented at an angle to the axis of rotation 17, i.e., to the direction of pull of the upper base body part 12 and the lower base body part 13. If the operator pulls the base body parts 12 and 13 apart with sufficient force, the hook head 3 slides along its angled contact surface 9 on the holding contour 4, thereby pressing the gripping hook 2 inwards towards the axis of rotation 17. This releases the snap connection 1 and separates the base body parts 12 and 13.

[0032] As in the Fig. 7 and 8As shown, the snap connection 1 of the preferred embodiment comprises two gripping hooks 2 with corresponding retaining contours 4. In an alternative embodiment, it may be advantageous to provide several gripping hooks 2 with several retaining contours 4. If the snap connection 1 comprises several gripping hooks 2, these are preferably distributed at uniform angular intervals in the circumferential direction of the axis of rotation 17. By using several gripping hooks 2, the holding forces of the snap connection 1 can be increased. Alternatively, the contact surface 9 of the hook head 3 and the retaining contour 4 operatively connected to it can also be adapted to adjust the desired holding force.

[0033] The attachment of a cutting head 10 to a working tool is carried out in the following steps: The operator turns the working tool 100 so that the end of the output shaft 18 points against gravity. The upper base part 12 is then threaded onto the output shaft 18. Next, the operator threads the cutting tools 14 onto the bearing pins 16, which are screwed onto the upper base part 12. The operator slides the lower base part 13 onto the upper base part 12 until the snap connection 1 engages. Finally, the entire cutting head 10 is screwed onto the output shaft 18 via the screw element 19 on the lower base part 13. Alternatively, the base parts 12 and 13 can be pre-assembled with the cutting tools 14 and then screwed onto the output shaft 18.

[0034] The snap-fit ​​connection 1 allows the operator to pre-assemble the base body parts 12, 13 with the cutting tool 14 and to screw the assembly of cutting head 10 and cutting tool 14 together onto the output shaft 18 of the working device 100. This prevents the operator from losing individual components when attaching the cutting head 10. This simplifies the assembly of the cutting head 10.

[0035] As in the Fig. 8 und 9 As shown, the cutting head 10 comprises an interference contour 40 and a guide groove 41. In the exemplary embodiment, the interference contour 40 is formed on the upper base body part 12. The guide groove 41, on the other hand, is formed on the lower base body part 13. In an alternative embodiment of the cutting head 10, the interference contour 40 can, of course, also be formed on the lower base body part 13 and the guide groove 41 on the upper base body part 12. As shown in particular in the Figuren 11 and 12As shown, the interference contour 40 is formed on the inner wall 37 of the upper base body part 12. The interference contour 40 is designed as a rib 42 extending in the axial direction, i.e., in the direction of the axis of rotation 17. To avoid material accumulation for manufacturing reasons, a recess is provided in the center of the rib 42. The ribs 42 project from the inner wall 37 of the upper base body part 12 into the central opening 36. In the exemplary embodiment, two interference contours 40 are provided, which have the same angular distance to each other in the circumferential direction with respect to the axis of rotation 17.

[0036] In the Fig. 14 und 15 The guide groove 41, formed on the dome 35 of the lower base body part 13, is shown. The guide groove 41 extends from the end face of the dome 35 away from the end face of the dome 35 in the direction of the axis of rotation 17. In the present embodiment, two guide grooves 41 are provided, arranged at equal angular intervals circumferentially to the axis of rotation 17, analogous to the interference contours 40. In this embodiment, the number of guide grooves 41 on the dome 35 corresponds to the number of interference contours 40 on the inner wall 37 of the upper base body part 12. It is also possible to have fewer interference contours 40 than guide grooves 41.

[0037] During the assembly of the cutting head 10, the interaction of the interference contour 40 and the guide groove 41 ensures that the upper base body part 12 and the lower base body part 13 can only be mounted in a predetermined position relative to each other. For assembly, the base body parts 12 and 13 must therefore be aligned circumferentially with each other. The upper base body part 12, with its interference contour 40, slides along the end face 47 of the dome 35 until the operator aligns the base body parts 12 and 13 relative to each other by rotating them, such that the interference contour 40 and the guide groove 41 are opposite each other in the direction of the axis of rotation 17. The upper base body part 12 has a collar 48 projecting axially beyond the interference element 40, with a collar end face 49, which assists the user in radially aligning the two base body parts 12 and 13 relative to each other during the rotation process.The interference contour 40 is designed in such a way that it can slide into the guide groove 41 and the base body parts 12, 13 can be pushed together.

[0038] The snap connection 1 and the interference contour 40 or the guide groove 41 are coordinated such that when the base body parts 12 are pushed together, the interference contour 40 must first slide into the guide groove 41 before the gripping hooks 2 can penetrate the retaining opening 8. Through the contact between the interference contour 40 and the guide groove 41, torques can be transmitted between the base body parts 12, 13 in the circumferential direction relative to the axis of rotation 17. As a result, the base body parts 12, 13 can no longer be rotated relative to each other as soon as the gripping hooks 2 penetrate the retaining opening 3 on the dome 35. Through the interaction of the interference contour 40 and the guide groove 41, the base body parts 12, 13 are connected to each other in a rotationally fixed manner. Interference contour 40 and guide groove 41 form a positive-locking connection in the circumferential direction relative to the axis of rotation 17. This prevents the operator from unintentionally twisting the base body parts 12, 13.This prevents the gripping hooks 2 from breaking off during the assembly process of the cutting head 10. The gripping hooks 2 of the snap connection 1 are protected during assembly by the interference contour 40 and the guide groove 41.

[0039] As in Fig. 9 As shown, the thread of the screw element 19 has a thread length g measured in the direction of the axis of rotation 17. The upper base body part 12 has a total axially measured immersion depth h, which corresponds to the distance between the collar end face 49 of the collar 48 and the end face 50 of the central opening 36. The interference contour 40 has an axially measured length i from the end face 50 of the central opening 36 to the end face of the interference contour 40. Furthermore, the gripping hook 2 has an immersion depth j, which, measured axially, extends from the end face 50 of the central opening 36 to the end of the hook head 3. The total immersion depth h is greater than the length i of the interference contour 40, so that when the base body parts 12, 13 are assembled, they are guided radially through the collar 48 first.The length i of the interference contour 40 is greater than the insertion depth j of the gripping hook 2, so that the interference contour 40 engages with the guide groove 41 first, and only then does the gripping hook 2 engage with the holding contour 4. The length i of the interference contour 40 is at least 120%, in particular 150%, preferably approximately 200% of the insertion depth j of the gripping hook 2. The interference contour j preferably corresponds approximately to the thread length g of the screw element 19.

[0040] As in Fig. 12 As shown, the interference contours 40 are located at half the angular distance, here 90°, between adjacent bearing bolts 16. This is advantageous because the guide groove 41 forms part of the cutting line receptacle. The gripping hooks 2 are preferably arranged centrally between adjacent bearing bolts 16 and interference contour 40. Depending on the structure of the base body part 12, 13 and corresponding stiffening ribs, the gripping hook 2 can also be arranged off-center between the bearing bolt 16 and the interference contour 40.

[0041] In Fig. 10 A sectional view of the cutting head 10 is shown, in which the cutting tools 14 are swivelled out to their maximum extent. The swivel angle α results from the two opposing swivel stops of the base body 11 for a corresponding cutting tool 14. In the Fig. 10 The maximum swivel angle α of the cutting tool 14 is shown, measured circumferentially from the longitudinal axis 29 of the cutting tool 14 to the bearing pin 16. The swivel angle α is preferably at least 60°, preferably at least 120°, and particularly approximately 200°. The swivel plane of the cutting tool 14 is arranged perpendicular to the axis of rotation 17. As shown in Fig. 7 As shown, the snap connection 1 has a distance a, measured radially to the axis of rotation 17, which is at most 40%, preferably at most 30%, and particularly 25% of the diameter d of the cutting head 10. The bearing axis 32 has a distance f to the axis of rotation 17. The distance f between the bearing axis 32 and the axis of rotation 17 is greater than the distance a between the snap connection 1 and the axis of rotation 17 (see Figure 1). Fig. 12Accordingly, the snap connection 1 lies radially to the axis of rotation 17 within the bearing axes 32 of the bearing pins 16. By positioning the snap connection 1 close to the axis of rotation 17, the components are moved into the interior of the cutting head 10. This allows the pivot gap 28 to remain sufficiently clear and a large pivot angle β to be achieved. Furthermore, the cutting tool 14 has a length b measured in its longitudinal direction, where the length b corresponds to at least 60% of the diameter d of the cutting head 10. In an alternative embodiment of the cutting head 10, the length b of the cutting blade 14 can also be shorter.

Claims

1. Cutting head for a motor strimmer, comprising a divided main body (11) having an upper main body part (12) and a lower main body part (13); wherein a screw element (19) is disposed on the lower main body part (13); wherein the screw element (19) serves for fastening to an output shaft (18) of a motor strimmer; wherein at least one receptacle (15) for fastening a cutting tool (14) is provided between the upper main body part (12) and the lower main body part (13); wherein the main body (11) is able to be rotationally driven about its rotation axis (17) during operation of a motor strimmer; wherein the upper main body part (12) and the lower main body part (13) are held to one another by means of a releasable snap-fit connection (1), characterized in that the snap-fit connection (1) has a spacing (a) which is measured in the radial direction relative to the rotation axis (17) and which is at most 40% of the diameter (d) of the cutting head (10).

2. Cutting head according to Claim 1, characterized in that the snap-fit connection (1) has a spacing (a) which is measured in the radial direction relative to the rotation axis (17) and which is at most 30%, preferably at most 25%, of the diameter (d) of the cutting head (10).

3. Cutting head according to Claim 2, characterized in that the receptacle (15) has a bearing axis (32) which extends in the direction of the rotation axis (17), wherein the bearing axis (32) possesses a spacing (f) from the rotation axis (17), and the spacing (f) between the bearing axis (32) and the rotation axis (17) is larger than the spacing (a) between the snap-fit connection (1) and the rotation axis (17).

4. Cutting head according to one of Claims 1 to 3, characterized in that the snap-fit connection (1) comprises at least one gripping hook (2), and at least one holding contour (4) which is operatively connected to the gripping hook (2).

5. Cutting head according to Claim 4, characterized in that the gripping hook (2) is disposed on the upper main body part (12), and the at least one holding contour (4) is disposed on the lower main body part (13).

6. Cutting head according to Claim 4 or 5, characterized in that the at least one gripping hook (2) has a hook head (3) which is specified to engage behind the at least one holding contour (4).

7. Cutting head according to Claim 6, characterized in that the hook head (3) is designed in such a manner that the snap-fit connection (1) latches when the main body parts (12, 13) are mutually compressed, and unlatches when the main body parts (12, 13) are pulled apart.

8. Cutting head according to one of Claims 1 to 7, characterized in that an interference contour (40) is provided on one of the two main body parts (12, 13), and a guide groove (41) which interacts with the interference contour (40) and extends in the direction of the rotation axis (17) is provided on the other main body part (12, 13), so as to mutually align the upper main body part (12) and the lower main body part (13) in the circumferential direction of the rotation axis (17) by means of the interference contour (40) and the guide groove (41).

9. Cutting head according to Claim 8, characterized in that the snap-fit connection (1) is designed in such a manner that the snap-fit connection (1) is able to be latched only in the case of the upper main body part (12) and the lower main body part (13) being mutually aligned by way of the interference contour (40) and the guide groove (41).

10. Cutting head according to Claim 8 or 9, characterized in that torques acting in the circumferential direction between the upper main body part (12) and the lower main body part (13) are able to be transmitted by way of the interference contour (40) and the guide groove (41).

11. Cutting head according to one of Claims 1 to 10, characterized in that the receptacle (15) is designed as a bearing pin (16), and a cutting tool (14) is able to be disposed on the main body (11) by way of the bearing pin (16).

12. Cutting head according to one of Claims 1 to 11, characterized in that the bearing pin (16) is fastened unilaterally to the upper main body part (12) or the lower main body part (13).

13. Cutting head according to Claim 11 or 12, characterized in that the bearing pin (16) is fastened to the upper main body part (12).

14. Cutting head according to one of Claims 1 to 13, characterized in that the screw element (19) is co-rotationally disposed on the lower main body part (13).

15. Cutting head according to one of Claims 1 to 14, characterized in that a cutting tool (14) is pivotably disposed on the at least one receptacle (15).