Guide bar having a saw chain
Patent Information
- Application Number
- PCT/EP2026/053297
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-18
- Filing Date
- 2026-02-09
- Publication Date
- 2026-08-27
Smart Images
Figure EP2026053297_27082026_PF_FP_ABST
Abstract
Description
[0001] A 1-98039 / a (A 45102) February 9, 2026
[0002] 1
[0003] Cutting attachment and chainsaw with a cutting attachment
[0004] The invention relates to a cutting assembly and a chainsaw with a cutting assembly.
[0005] It is common practice to provide cutting attachments for chainsaws, which include a guide bar and a saw chain. The guide bar and saw chain of a cutting attachment are matched in design and dimensions to achieve a good cutting result.
[0006] EP 4252984 Al discloses a chainsaw with a guide bar and a saw chain arranged around it. The guide bar has a sprocket nose at its deflection point. The drive links engage in the sprocket nose as they rotate around the bar tip. The guide bar and saw chain are aligned so that, as the sprocket nose rotates around the bar tip, the drive links are lifted from the guide surfaces of the guide bar.
[0007] By lifting the saw chain from the guide bar in the deflection section, the friction between the saw chain and the guide bar, and thus the wear of the guide bar at the bar tip, is reduced.
[0008] It has been observed that on guide rails with a deflection star, the guide groove in the area of the deflection star widens, and the bearing bolts of the deflection star bearing can loosen or come loose as a result. This renders the guide rail unusable.
[0009] The invention is based on the objective of providing a cutting attachment with improved durability. A further objective of the invention is to provide a chainsaw whose cutting attachment has improved durability. A 1-98039 / a (A 45102) 09 February 2026
[0010] 2
[0011] This problem is solved with respect to the cutting attachment by a cutting attachment having the features of claim 1. With respect to the chainsaw, the problem is solved by a chainsaw having the features of claim 10.
[0012] It has been shown that the widening of the guide groove in the area of the deflection arm, which occurs during operation, can be particularly promoted by making plunge cuts. When making plunge cuts, the saw chain is engaged with the workpiece in the area of the guide bar tip. Often, only one cutting link is engaged with the workpiece at any given time. The cutting teeth of saw chains typically have cutting edges inclined to the direction of travel. As a result, when making a cut, forces not only act on the cutting link in the longitudinal direction of the saw chain, but also perpendicular to the longitudinal direction. These forces acting perpendicular to the longitudinal direction of the saw chain can tilt the drive link in such a way that the drive end presses laterally against the longitudinal side of the guide groove, thereby widening the guide groove.
[0013] The plan is to align the guide bar and saw chain so that, when rotating around the guide bar, the running surfaces of the saw chain maintain a distance of 0 mm to a maximum of 0.15 mm from the guide surfaces, at least at the bar tip. A distance of 0 mm corresponds to the saw chain being in contact with the guide surfaces of the guide bar.
[0014] With known cutting assemblies, this distance is significantly larger, for example, approximately 1 mm. Due to the very small distance or the contact of the saw chain with the guide surfaces, the immersion depth of the drive link on the sprocket nose is increased. This reduces the degree to which the drive link can tilt in the guide groove and significantly decreases the widening of the guide groove in the area of the bar tip. A 1-98039 / a (A 45102) 09 February 2026
[0015] 3
[0016] The distance is measured specifically parallel to a longitudinal center axis of the guide bar. This distance is the smallest gap between the running surfaces of the saw chain and the guide surfaces as it moves around the bar tip.
[0017] If the saw chain rests against the guide surfaces at the tip of the guide bar, the load is distributed primarily via both the guide surfaces and the sprocket nose. This reduces the load on the sprocket nose bearing and increases the guide bar's lifespan. If the saw chain is close to the guide surfaces, the sprocket nose bearing play can be overcome under load, and the saw chain can come into contact with the guide surfaces. Therefore, even with a clearance of up to 0.15 mm between the saw chain's running surfaces and the guide surfaces, the load during operation, particularly during plunge cuts, can be distributed via both the guide surfaces and the sprocket nose.
[0018] In particular, the distance between the running surfaces and the guide surfaces is adjusted to the bearing of the deflection star so that the saw chain rests against the guide surfaces under normal operating load, especially under the load typical when performing a plunge cut.
[0019] With guide bars featuring a deflection arm, where the saw chain is significantly lifted from the guide surfaces at the bar tip, considerable wear can occur during operation in the area where the saw chain, lifted by the deflection arm, re-engages with the guide surfaces of the guide bar. It has been shown that this wear can be significantly reduced with a saw chain whose running surfaces at the bar tip have a distance of 0 mm to 0.15 mm from the guide surfaces of the guide bar.
[0020] In order to maintain the desired distance between running surfaces and guide rail at the rail tip of 0 mm to 0.15 mm even during operation of the cutting assemblies, the deflection star is designed to have V-shaped recesses. A 1-98039 / a (A 45102) 09 February 2026
[0021] 4
[0022] The guide bar has a V-shaped recess in the guide bar into which the drive links' prongs engage as they rotate around the bar tip. During a plunge cut, forces act on the cutting link in the longitudinal direction of the saw chain. These forces cause a pivoting torque on the cutting link about a pivot axis parallel to the axis of rotation of the guide bar. Due to this pivoting torque, even when the running surfaces are in contact with the guide surfaces, the cutting link can cause excessive wear on the guide surfaces, resulting in a gap between the running surfaces and the guide bar exceeding 0.15 mm. V-shaped recesses in the guide bar, into which the drive links engage, limit or prevent the pivoting of the drive links, and thus also the cutting links, about pivot axes parallel to the axis of rotation of the guide bar. This reduces wear on the guide surfaces, allowing the desired gap to be maintained for a comparatively long time during operation.
[0023] V-shaped in this context means that a first, leading flank and a second, trailing flank of the recesses form an angle that opens away from the axis of rotation of the sprocket nose. The flanks of the recesses are the areas where the drive links' prongs can make contact when the saw chain is guided only by the sprocket nose.
[0024] In particular, the distance between the running surfaces of the saw chain and the guide surfaces at the tip of the rail is from 0 mm to a maximum of 0.1 mm.
[0025] In particular, the distance between the running surfaces of the saw chain and the guide surfaces at the bar tip shall not exceed 10%, and in particular not exceed 5%, of the immersion depth of the drive end into the guide groove at the bar tip. The distance between the running surfaces of the saw chain and the guide surfaces shall be measured, in particular, along the longitudinal center axis of the guide bar. A 1-98039 / a (A 45102) 09 February 2026
[0026] 5
[0027] The guide bar has, in particular, an imaginary guide circle. The guide circle is a circle that extends around the axis of rotation of the guide bar. The running surfaces of the saw chain run on the guide circle when the saw chain is guided by the guide bar. The radius of the guide circle corresponds, in particular, to the distance between the axis of rotation of the guide bar and an imaginary guide surface on which the saw chain at the bar tip would run around the axis of rotation at the same distance as the saw chain guided by the guide bar. The guide circle takes into account the geometry of the guide bar and the saw chain, especially the running surfaces and the drive points.
[0028] The guide surface has a guide surface distance to the axis of rotation of the deflection star, measured in the direction of the axis of rotation.
[0029] In particular, the distance between the guide surfaces at the bar tip is at least as large as the radius of the guide circle, and preferably larger than the radius of the guide circle. This ensures that the saw chain rests against the guide surfaces even without a load at the bar tip. If the distance between the guide surfaces is larger than the radius of the guide circle, the saw chain initially rests only against the guide surfaces. The sprocket nose does not initially contribute to load distribution. However, it has been shown that the guide surfaces wear quickly in this case until the sprocket nose also contributes to load distribution. By slightly increasing the distance between the guide surfaces compared to the guide circle, manufacturing tolerances can be easily compensated for, so that even with unfavorable tolerances, load distribution occurs via the guide surfaces.
[0030] The saw chain is not lifted from the guide rail in the deflection section, particularly at the rail tip. Because the saw chain rests against the guide surfaces of the guide rail, at least at the rail tip, the drive links can engage deeper into the guide groove and are guided over a greater height of the drive attachment within the groove. This prevents lateral tilting. A 1-98039 / a (A 45102) 09 February 2026
[0031] 6
[0032] The force exerted on the drive links during plunge cutting is reduced, and the transverse forces exerted on the longitudinal sides of the guide groove become smaller.
[0033] In particular, the difference between the guide surface distance and the radius of the guide circle at the bar tip is at most 0.3 mm, and especially at most 0.2 mm if the guide surface distance is greater than the radius of the guide circle. Because the guide surface distance is only slightly greater than the radius of the guide circle, the guide surfaces at the bar tip wear down quickly during operation, and the saw chain bears against both the guide surfaces and the guide post after only a short operating time.
[0034] The guide surface distance, less the radius of the guide circle, is, in particular over an angle of at least 50°, and in particular at least 90°, around the axis of rotation of the deflection star, from -0.15 mm to +0.3 mm, and in particular from -0.1 mm to +0.2 mm. The value is negative if the guide surface distance is less than the radius of the guide circle, and positive if the guide surface distance is greater than the radius of the guide circle.
[0035] The angle of extension, in which the distance between the guide surfaces minus the radius of the guide circle ranges from -0.15 mm to +0.3 mm, extends, in particular, from the longitudinal center axis 31 over at least 25° to both sides. High lateral forces typically act on the saw chain in this area when it is engaged with a workpiece.
[0036] In particular, the drive elements of the drive links have a leading flank and a trailing flank that can come into contact with the sides of the V-shaped recesses.
[0037] The driving elements feature, in particular, a first, leading flank and a second, trailing flank, which enclose a first angle. The recesses wei-A 1-98039 / a (A 45102) 09 February 2026
[0038] 7
[0039] They feature, in particular, a first, leading side and a second, trailing side, which enclose a second angle. The first and second angles are, in particular, equal in size. Because the first and second angles are equal, the drive elements can, in particular, come into contact with the opposite sides of the recesses with both flanks. This ensures good guidance of the drive elements. Pivoting of the drive elements, and thus also of the connecting elements, about a pivot axis parallel to the axis of rotation of the deflection star, can thereby be reduced or prevented.
[0040] In conventional cutting attachments, the angular spacing of the grooves and the pitch of the saw chain are designed to anticipate a certain amount of chain elongation during operation due to wear when the cutting attachment is new. The pitch is slightly smaller than would be necessary for a central arrangement of multiple drive links in the grooves of the guide bar. As a result, when new, only one drive link can have both flanks in contact with the sides of its assigned groove. For all other drive links, one flank remains separated from its corresponding side of the groove. The drive links that only make contact with the groove on one flank can pivot around an axis parallel to the axis of rotation of the guide bar, thereby causing increased wear on the guide surfaces.
[0041] It is now specifically intended that the angular spacing of the recesses and the pitch of the saw chain are coordinated so that, with multiple drive links, both the leading (first) flanks and the trailing (second) flanks would simultaneously bear against the sides of the recesses if the saw chain were guided only by the deflection bar. With this design, contact between both flanks can be prevented by the guide surfaces when the saw chain is guided on the guide bar, if the distance between the guide surfaces is greater than the radius of the guide circle. If the distance between the guide surfaces is less than or equal to the radius of the guide circle, then, with multiple drive links, both the leading and trailing flanks simultaneously bear against the sides of the recesses. A 1-98039 / a (A 45102) February 9, 2026
[0042] 8
[0043] The first flanks as well as the trailing, second flanks on the sides of the depressions when the saw chain runs around the guide bar.
[0044] Alternatively or additionally, the angular spacing of the recesses and the pitch of the saw chain can be coordinated so that the drive leads of several drive links can be arranged centrally in the assigned recesses when the saw chain is mounted on the guide bar.
[0045] The pitch of the saw chain is half the distance, measured with the saw chain stretched, between the center axis of one connecting bolt and the center axis of the next connecting bolt in the direction of travel.
[0046] The drive elements and the recesses are specifically designed so that, when rotating around the guide rail, the drive elements do not come into contact with the bottom of the recesses, which is radially inward relative to the axis of rotation. The drive elements are supported exclusively on one or both sides of the recesses.
[0047] A chainsaw comprises a cutting attachment and a drive motor to power the saw chain of the cutting attachment.
[0048] The drive motor can be, in particular, an internal combustion engine, especially a two-stroke engine or a four-stroke engine with mixed lubrication, or an electric motor. If the drive motor is an electric motor, the chainsaw will, in particular, have a battery for power supply.
[0049] An embodiment of the invention is explained below with reference to the drawing. The drawing shows:
[0050] Fig. 1 a schematic representation of a chainsaw, A 1-98039 / a (A 45102) 09 February 2026
[0051] 9
[0052] Fig. 2 shows a partial view of a saw chain,
[0053] Fig. 3 is a schematic top view of a cutting tooth of the saw chain from Fig. 2, showing the forces acting during operation.
[0054] Fig. 4 shows a schematic representation of the cutting assembly in the area of the rail tip, with the part of the guide rail located in front of the deflection point hidden.
[0055] Fig. 1 schematically shows a chainsaw 1. The chainsaw 1 is a hand-held, hand-operated tool. The chainsaw 1 comprises a housing 2 on which handles 3 and 4 are arranged. In the exemplary embodiment, handle 3 is a rear handle and handle 4 is a handle tube. A cutting assembly 40 is arranged on the housing 2 of the chainsaw 1. The cutting assembly 40 comprises a guide bar 5 and a saw chain 6 guided around the circumference of the guide bar 5.
[0056] The chainsaw 1 comprises a drive motor 7 for driving the saw chain 6. In the exemplary embodiment, the drive motor 7 drives the saw chain 6 via a drive sprocket 8. The guide bar 5 is held in place by a sprocket cover 9 on the housing 2. The sprocket cover 9 covers the area of the drive sprocket 8.
[0057] The end of the guide rail 5 fixed to the housing 2 is a mounting end 10. At the end opposite the mounting end 10, the guide rail 5 has a deflection section 11. A deflection star 17 is rotatably mounted in the deflection section 11 about a pivot axis 18. The deflection star 17 is shown schematically by a dotted line in Fig. 1.
[0058] The guide rail 5 has a base body 15. The base body 15 can be made of one piece or multiple pieces. The guide rail has guide surfaces 16A 1-98039 / a (A 45102) 09 February 2026
[0059] 10
[0060] The guide surfaces 16 are formed at least partially on the base body 15. In the resting state, the saw chain 6 is tensioned against the guide bar 5 and is stationary and not driven. During operation, the saw chain 6 is driven in a direction of travel 30.
[0061] The guide rail 5 has a longitudinal center axis 12. The longitudinal center axis 12 extends longitudinally along the guide rail 5 through the axis of rotation 18 of the deflection star 17. The longitudinal center axis 12 also extends through an axis of rotation 39 of the drive pinion 8. The longitudinal center axis 12 intersects the guide surfaces 16 at a rail tip 13 when viewed in the direction of rotation of the axis of rotation 18.
[0062] As Fig. 1 also shows, the guide rail 5 has a guide groove 14. The guide groove 14 extends at least into the base body 15. Drive lugs 27 of the saw chain 6 engage in the guide groove 14.
[0063] Fig. 2 shows an exemplary assembly of the saw chain 6. Other assemblies of the saw chain 6 may also be advantageous. The saw chain 6 comprises lateral connecting links 20 and central drive links 21. The connecting links 20 and the drive links 21 are pivotally mounted via connecting pins 25. The connecting pins 25 have central axes 26. The central axes 26 form the pivot axes of the connecting links 20 and drive links 21.
[0064] The saw chain 6 has a pitch t. The pitch t is half of a distance 2t from the central axis 26 of a connecting bolt 25 to the central axis 26 of the next connecting bolt 25 in the direction of travel 30.
[0065] Some of the connecting elements 20 are designed as cutting elements 22. In the direction of travel 30, cutting elements 22 with right-hand cutting teeth 23a and cutting elements 22 with left-hand cutting teeth 23b are arranged alternately. Leading up to each A 1-98039 / a (A 45102) February 9, 2026
[0066] 11
[0067] A depth gauge 24 is provided on cutting teeth 23a, 23b. In the exemplary embodiment, the depth gauges 24 are each formed on a cutting element 22. The depth gauges 24 can also be formed on a drive element 21.
[0068] The deflection stem 17 has recesses 32 on its circumference as shown in Fig. 4. The recesses 32 are V-shaped.
[0069] Fig. 2 schematically shows a recess 32 on a drive lug 27 with a dotted line. The drive lug 27 has a first, leading flank 28 and a second, trailing flank 29. The recess 32 has a first, leading side 41 and a second, trailing side 42. In the exemplary embodiment, sides 41 and 42 are formed by flat areas of the wall of the recess 32. The recess 32 and the drive lug 27 are aligned such that the drive lug 27 can contact the sides of the recess 32 with both flanks 28 and 29. The geometry of the drive lug 27 and the recess 32 therefore determines how far the drive lug 27 can engage in the recess 32.
[0070] The saw chain 6 has a longitudinal center axis 31. The longitudinal center axis 31 intersects the center axes 26 of the connecting bolts 25 perpendicularly and centrally between the outer surfaces of the connecting links 20. Each connecting link 20, including each connecting link 20 designed as a cutting link 22, has two running surfaces 33. The running surfaces 33 of the connecting links 20 slide on the guide surfaces 16 of the guide bar 5 during operation. The running surfaces 33 can, for example, run parallel to the longitudinal center axis 31 or inclined to the longitudinal center axis 31.
[0071] Fig. 3 schematically shows the forces acting on a left cutting tooth 23b in cross-section. The cutting tooth 23b has a roof cutting edge 34 which, in a top view of the cutting tooth 23b, is inclined at an angle to the longitudinal center axis 31 that deviates from 90°. A cutting force F acting during operation s acts perpendicularly on the roof edge 34. This cutting force F scan be placed in a position parallel to the longitudinal center axis 31 wir-A 1-98039 / a (A 45102) 09 February 2026
[0072] 12
[0073] end axial force F L and a transverse force FQ acting perpendicular to the longitudinal center axis 31 is resolved. The transverse force FQ acting perpendicular to the longitudinal center axis 31 causes a tilting of the respective cutting element 22, particularly when only one cutting tooth 23a, 23b is in engagement with a workpiece. This is especially the case when a plunge cut is performed in the area of the rail tip 13.
[0074] Fig. 4 shows the design of the cutting pattern 40 in the deflection section 11. The deflection section 11 is the longitudinal section of the guide rail 5 that extends from the axis of rotation 18 of the deflection star 17 to the rail tip 13. In Fig. 4, the design of guide surfaces according to the prior art is shown with a dashed line 36. The course of the guide surfaces 16 of a guide rail 5 according to the invention is shown with a dashed line 38. The representation in Fig. 4 is merely schematic.
[0075] The guide rail 5, in particular the guide surfaces 16 of the guide rail 5, can be hardened, especially in the area of the rail tip 13.
[0076] In the deflection section 11, the drive projections 27 of the drive links 21 engage in the recesses 32. The drive projections 27 can, for example, protrude between side plates of the guide rail 5 (not shown in detail). The deflection star 17 can, for example, be mounted in the side plates. The side plates can be formed on the base body 15 or be formed separately from the base body 15 and connected to it.
[0077] The deflection arm 17 is rotatably mounted about the axis of rotation 18 by means of a bearing 19. The bearing 19 is fixed to the base body 15 of the guide rail 5 by means of bearing bolts 37.
[0078] The deflection star 17 has an imaginary guide circle 35, which is shown with a dotted line in Fig. 4. The guide circle 35 is a concentric circle around the axis of rotation 18 of the deflection star 17. The guide circle 35 has a radius b. [The following appears to be a separate, unrelated entry:] Guide-A 1-98039 / a (A 45102) February 9, 2026
[0079] 13
[0080] The guide circle 35 is the circle on which the running surfaces 33 of the saw chain 6 would rotate at the guide bar tip 13 if the saw chain 6 were guided only by the sprocket nose 17. The radius b of the guide circle 35 depends on the geometry of the recesses 32 and the geometry of the drive lugs 27. A typical radius b of the guide circle 35 of a sprocket nose 17 can, for example, be approximately 16 mm.
[0081] As shown in Fig. 4, the drive elements 27 engage in the deflection section 11 with an immersion depth a in the deflection stem 17. The immersion depth a is measured relative to the guide circle 35. The immersion depth a corresponds to the distance, measured radially to the axis of rotation 18, of the radially inner area of the drive elements 27 to the guide circle 35.
[0082] In known guide rails, the deflection star 17 lifts the saw chain 6 from the guide surfaces 16 in the deflection section 11. When viewed in the direction of the axis of rotation 18, the guide surfaces 16 have a guide surface distance c' to the axis of rotation 18, measured parallel to the longitudinal center axis 12 of the guide rail 5. The guide surface distance c' is smaller than the radius b of the guide circle 35. A distance d', corresponding to the difference between the guide surface distance c' and the radius b, is, for example, 0.5 mm to 1.5 mm in the prior art. The saw chain 6 is lifted from the guide rail 5 by the distance d' at the guide rail tip 13. Therefore, in the deflection section 11, all forces introduced into the saw chain 6 by the workpiece are absorbed by the deflection star 17.
[0083] In the exemplary embodiment, the guide surfaces 16 have a guide surface distance c relative to the axis of rotation 18 of the deflection star wheel 17, viewed in the direction of rotation 18. The guide surface distance c of the guide surface 16 at the bar tip 13 relative to the axis of rotation 18 is greater than the radius b of the guide circle 35. The difference between the guide surface distance c and the radius b corresponds to a distance d. The guide surface distance c minus the radius b of the guide circle 35 is -0.15 mm to +0.3 mm at the bar tip 31, in particular from -0.1 mm to +0.2 mm. As a result, the saw chain 6 rests against the guide surfaces 16 at the bar tip 13. A 1-98039 / a (A 45102) February 9, 2026
[0084] 14
[0085] or has a distance to these of at most 0.15 mm, in particular of at most 0.1 mm.
[0086] The distance d corresponds to the distance between the running surfaces 33 of the saw chain 6 at the guide bar tip 13 and the guide surface 16, if the guide surface distance c is less than the radius b. In particular, the distance d between the running surfaces 33 of the saw chain 6 and the guide surfaces 16 at the guide bar tip 13 is at most 10%, and more specifically, at most 5% of the immersion depth a of the drive attachment 27 in the guide groove 14 at the guide bar tip 13. The distance d is measured along the longitudinal center axis 31.
[0087] In particular, the guide surface distance c at the rail tip 13 is at least as large as the radius b of the guide circle 35.
[0088] If the guide surface distance c is greater than the radius b, the saw chain 6 will not be lifted from the guide bar 5 at the bar tip 13. The saw chain 6 will slide along the guide surfaces 16. This will cause the guide surfaces 16 to wear down until forces from the saw chain 6 can also be transmitted to the sprocket nose 17. The guide surface distance c is at most 0.3 mm, and in particular at most 0.2 mm, greater than the radius b of the guide circle 35.
[0089] It can also be provided that the guide surface distance c and the radius b of the guide circle 35 are equal. The saw chain 6 is then guided by the guide surfaces 16 and the deflection star 17, and forces are absorbed by both the guide surfaces 16 and the deflection star 17.
[0090] It can also be provided that the guide surface distance c is smaller than the radius b. The guide surface distance c is, in particular, 0.15 mm, and especially 0.1 mm, smaller than the radius b. This causes the saw chain 6 to be slightly lifted from the guide surfaces 16 by the deflection star wheel 17. Under load, for example during a plunge cut, a force is exerted by the saw chain 6 in the direction of the longitudinal center axis 12A 1-98039 / a (A 45102) February 9, 2026
[0091] 15
[0092] The force is exerted on the deflection star 17. This allows, for example, the play of the bearing 19 to be overcome and the saw chain 6 to come into contact with the guide surfaces 16. This enables the deflection star 17 and the guide surfaces 16 to contribute to load transfer.
[0093] In the exemplary embodiment, the guide surface distance c minus the radius b of the guide circle 35 is not only at the rail tip 13, but over an extension angle a of at least 50°, in particular at least 90°, in particular at least 120°, in particular at least 150° around the axis of rotation 18 from -0.15 mm to +0.3 mm, in particular from -0.1 mm to +0.2 mm.
[0094] In particular, half an angle of extension a measured to the longitudinal center axis 31 shall be at least 25°.
[0095] In particular, the extension angle a extends from the longitudinal center axis 31 to both sides over at least 25°.
[0096] The recess 32 has a base 43. The base 43 is the area of the recess 32 that limits the recess 32 in the direction of the axis of rotation 18. The drive element 27 and the recess 32 are designed such that the drive element 27 cannot come into contact with the base 43. During its rotation around the rail tip 13, the drive element 27 maintains a distance g from the base 43 in every rotational position of the deflection star 17. The smallest distance g occurs, in particular, when both flanks 28 and 29 are in contact with the sides 41 and 42 of a recess 32.
[0097] The first, leading flank 28 and the second, trailing flank 29 enclose an angle β. The angle β is, in particular, 60° to 120°, and more specifically, 70° to 90°. The first, leading side 41 and the second, trailing side 42 of the recess 32 enclose an angle y. The angle y is, in particular, 60° to 120°, and more specifically, 70° to 90°. The angle β and the angle y are, in particular, A 1-98039 / a (A 45102) 09 February 2026
[0098] 16
[0099] The flanks 28 and 29 and the sides 41 and 42 are flat in the areas where sides 41 and 42 can come into contact with flanks 28 and 29 when the saw chain 6 is guided only by the deflection arm 17. This results in a flat contact of the drive end 27 with the two opposite sides 41 and 42 of the recess 32.
[0100] Each recess 32 has an angle bisector 44. The angle bisector 44 is the angle bisector of the second angle y. The sides 41 and 42 of the recesses 32 are, in particular, mirror-symmetrical to each other. The angle bisector 44 passes through the axis of rotation 18 of the deflecting star 17.
[0101] The sides 41 and 42 of a depression 32 each enclose an angle 5 with the angle bisector 44, which corresponds to half of the second angle y.
[0102] The angle bisectors 44 of adjacent recesses 32 enclose an angle 8. The angle 8 and the pitch t of the saw chain 6 are coordinated such that, with several drive links 21, both the leading, first flanks 28 and the trailing, second flanks 29 would simultaneously bear against the sides 41 and 42 of the recesses 32 if the saw chain 6 were guided only by the deflection sprocket 17.
[0103] Alternatively or additionally, the design can be such that the drive elements 27 of several drive links 21 can be arranged centrally in the associated recesses 32 when the saw chain 6 is arranged on the guide bar 5.
Claims
A 1-98039 / a (A 45102) February 9, 2026 17 Claims 1. Cutting assembly for a chainsaw comprising a guide bar (5) and a saw chain (6) guided circumferentially on the guide bar, wherein the saw chain (6) has lateral connecting links (20) and central drive links (21) which are pivotally connected to one another via connecting bolts (25), wherein the guide bar (5) has a guide groove (14), wherein the drive links (21) each have at least one drive lug (27), wherein the drive lugs (27) engage in the guide groove (14), wherein the connecting links (20) have running surfaces (33) which are guided on guide surfaces (16) of the guide bar (5) formed on both sides of the guide groove (14), wherein the guide bar (5) comprises a deflection sprocket (17) which is rotatably mounted in a deflection section (11) of the guide bar (5) about an axis of rotation (18), wherein the drive lugs (27) in the deflection section (11) engage in the deflection star (17),wherein the deflecting star (17) has V-shaped recesses (32) on its circumference into which the driving elements (27) of the driving links (21) engage when rotating around the rail tip (13), characterized in that the saw chain (6) and the guide bar (5) are matched to each other in such a way that the running surfaces (33) of the saw chain (6) when rotating around the guide bar (5) have a distance (d) of 0 mm to a maximum of 0.15 mm to the guide surfaces (16) at least at the bar tip (13).
2. Cutting diagram according to claim 1, characterized in that the distance (d) is 0 mm to 0.1 mm.
3. Cutting dgamitur according to claim 1 or 2, characterized in that the deflection star (17) has an imaginary guide circle (35) around the axis of rotation (18) of the deflection stem (17), wherein the guide circle (35) is the circle on which the running surfaces (33) of the saw chain (6)A 1-98039 / a (A 45102) 09 February 2026 18 would be guided around the rail tip (13) if the saw chain (6) were guided only by the deflecting star (17), and that the guide surface (16) to the axis of rotation (18) of the deflecting star (17) has a guide surface distance (c) measured in the direction of view of the axis of rotation (18).
4. Cutting diagram according to claim 3, characterized in that the guide surface distance (c) at the rail tip (13) is at least as large as a radius (b) of the guide circle (35), in particular larger than the radius (b) of the guide circle (35).
5. Cutting diagram according to claim 4, characterized in that the difference between the guide surface distance (c) and the radius (b) of the guide circle (35) at the rail tip (13) is at most 0.3 mm.
6. Cutting dgamitur according to one of claims 3 to 5, characterized in that the guide surface distance (c) minus the radius (b) of the guide circle (35) over an extension angle (a) of at least 50° about the axis of rotation (18) of the deflecting star (17) is from -0.15 mm to +0.3 mm.
7. Cutting dgamitur according to one of claims 1 to 6, characterized in that the driving elements (27) have a first, leading flank (28) and a second, trailing flank (29) enclosing a first angle (β), that the recesses (32) have a first, leading side (41) and a second, trailing side (42) enclosing a second angle (y), and that the first angle (β) and the second angle (y) are of equal measure. A 1-98039 / a (A 45102) 09 February 2026 19 8. Cutting dgamitur according to one of claims 1 to 7, characterized in that an angular distance (s) of the recesses (32) and a pitch (t) of the saw chain (6) are coordinated such that, with several drive links (21), both the leading, first flanks (28) and the trailing, second flanks (29) would simultaneously bear against the sides (41, 42) of the recesses (32) if the saw chain (6) were guided only by the deflection stem (17).
9. Cutting dgamitur according to one of claims 1 to 8, characterized in that the drive projections (27) and the recesses (32) are aligned in such a way that the drive projections (27) do not come into contact with a bottom (43) of the recesses (32) which is radially inside with respect to the axis of rotation (18) when rotating around the guide rail (5).
10. Chainsaw with a cutting attachment according to one of claims 1 to 9, wherein the chainsaw (1) has a drive motor (7) for driving the saw chain (6) of the cutting attachment (40).