SAW CHAIN

Description

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

[0002] DE 43 09 464 A1 discloses a saw chain whose rivet bolts have recesses on both ends. The recesses are designed with a continuous radius and are comparatively large. This is intended to increase the friction pressure between the rivet shank and the rivet hole, as increased radial pressure builds up in the rivet shank during the deformation process.

[0003] DE 740 549 C and US 2 798 381 A each disclose chains with a chain lock which has a slot on one end face for the engagement of a screwdriver.

[0004] The invention is based on the object of providing a saw chain of the generic type which has a long service life.

[0005] This problem is solved by a saw chain having the features of claim 1. The problem is also solved by a saw chain having the features of claim 10.

[0006] It has been shown that excessive radial pressure on the rivet bolt can lead to reduced service life of the saw chain.

[0007] According to the invention, the recess has a recess edge whose distance from the center plane of the saw chain increases with increasing radial distance from the rivet bolt axis. The recess also has a recess base enclosed by the recess edge, whereby the distance of the recess base from the center plane of the saw chain does not increase at any point on the recess base with increasing radial distance from the rivet bolt axis. The greatest distance of the recess base from the rivet bolt axis corresponds to 30% to 100% of half the core diameter of the rivet bolt.

[0008] It has been shown that the specified design reduces the radial forces acting on the opening in the adjacent connecting link while still achieving a high degree of riveted joint strength. Because the distance between the recess base and the center plane of the saw chain does not increase at any point along the recess base with increasing radial distance from the rivet bolt axis, only comparatively low radial forces are introduced into the opening of the connecting link in the area of ​​the recess base during riveting. The rivet is compressed in the area around the rivet bolt axis that is covered by the recess base when viewed in the direction of the rivet bolt axis. This results in high riveting forces.

[0009] For rivet studs with a circular cross-section, half the core diameter is the smallest radius of the rivet stud. For rivet studs with a collar in the drive link, half the core diameter corresponds to the radius of the rivet stud in a connecting link.

[0010] The rivet bolt can be formed separately from the two connecting links and the drive link, which the rivet bolt connects to each other in an articulated manner. In this case, the rivet bolt protrudes through rivet openings of two connecting links and a rivet opening of a drive link arranged between the connecting links. In an alternative embodiment, the rivet bolt can be formed integrally with one of the connecting links and protrudes through a rivet opening of a drive link and a rivet opening of the opposite connecting link. The recess is advantageously arranged on the side of a rivet bolt on which the rivet bolt protrudes through a rivet opening of a connecting link and is connected to the connecting link.

[0011] The maximum distance between the recess base and the rivet bolt axis is preferably at least 50% of half the rivet bolt's core diameter. The specified minimum size of the recess base limits the forces introduced into the recess base during riveting, thus avoiding excessive material stress.

[0012] In a particularly advantageous design, the recess base is convexly curved. This directs the forces introduced during riveting in the area of ​​the recess base away from the edge of the opening of the adjacent connecting link and toward the rivet bolt axis. A recess base that runs at least partially, and in particular completely, perpendicular to the rivet bolt axis can also be advantageous.

[0013] Advantageously, the greatest distance between the recess base and the rivet bolt axis corresponds to a maximum of 80% of half the core diameter of the rivet bolt.

[0014] The greatest distance of the recess from the rivet bolt axis is advantageously at least 110% of the greatest distance from the recess base to the rivet bolt axis. This results in a comparatively small increase in the recess in the area of ​​the recess edge, i.e., a slight increase in the distance of the recess edge from the center plane with increasing distance from the rivet bolt axis. This comparatively small increase in the recess in the area of ​​the recess edge ensures favorable force transmission.

[0015] The depth of the recess is preferably comparatively small. The depth of the recess is measured parallel to the rivet bolt axis. The depth of the recess is the difference between the greatest distance from the recess edge to the center plane and the smallest distance from the recess base to the center plane. The depth of the recess is advantageously smaller than the greatest distance from the recess base to the rivet bolt axis. The depth of the recess is in particular less than 40%, advantageously less than 30% of the greatest distance from the recess base to the rivet bolt axis. The recess is advantageously comparatively shallow.

[0016] At least one end face of a rivet bolt is advantageously formed on a rivet head with an enlarged outer diameter, which projects beyond the outer surface of the associated connecting link. The recess is located in particular at least partially outside the plane of the outer surface of the associated connecting link. Preferably, the recess is located completely outside the plane of the outer surface of the associated connecting link. The associated connecting link is the connecting link that is arranged on the same side of the chain as the rivet head. The rivet head bears in particular against the associated connecting link. In an alternative embodiment, it can be provided that the end face of the rivet bolt is flush with the outer surface of the associated connecting link or is offset from the outer surface towards the center plane of the saw chain. The depth of the recess is in particular smaller than a height of the rivet head measured in the direction of the rivet bolt axis.The depth of the recess is in particular less than 50%, advantageously less than 30% of the height of the rivet head.

[0017] Advantageously, the ratio of half the enlarged outer diameter of the rivet head to the greatest distance between the recess base and the rivet bolt axis is between 1.5 and 3.5. Particularly advantageously, the ratio of half the enlarged outer diameter of the rivet head to the greatest distance between the recess base and the rivet bolt axis is between 2 and 3.5.

[0018] The connecting link advantageously has a chamfer at the rivet opening. The chamfer is arranged in particular on the outside of the rivet opening, i.e. on the side of the rivet opening facing away from the center plane. The depth of the chamfer at the rivet opening of the connecting link is advantageously comparatively small. The depth of the chamfer at the rivet opening is advantageously at most 30%, in particular at most 20% of the thickness of the connecting link. As a result, the largest diameter of the chamfer, which is arranged on the outside of the connecting link, is also comparatively small. For a rivet bolt with a rivet head, it is advantageously provided that the rivet head completely covers the chamfer. The enlarged outer diameter of the rivet head is advantageously at least 120% of the largest diameter of the chamfer. The greatest distance of the recess base from the rivet bolt axis is advantageously at least 20%, in particular at least 40% of half the largest diameter of the chamfer.

[0019] The rivet bolt is preferably a collar bolt. The rivet bolt advantageously has a collar that is positioned in the rivet opening of the drive link. The collar advantageously does not protrude into the rivet openings of the connecting links. The collar bolt can be used to easily ensure sufficient distance between the two connecting links through which the collar bolt protrudes.

[0020] An independent inventive idea according to claim 10 relates to the design of the two end faces of the rivet bolt of the saw chain. The rivet bolt is designed as a solid body and has a first and a second end face that are differently designed. By using a rivet bolt with different first and second end faces, different forces acting on the two end faces of the rivet bolt or other influences on the riveting that act differently on the two end faces of the rivet bolt can be at least partially compensated. In particular, it has been shown that the forces acting on the saw chain during operation can be different on both sides of the saw chain, for example due to the arrangement of the drive unit or the handles via which the forces are introduced during operation.Lateral forces are also introduced into the saw chain via the cutting links, which can lead to asymmetrical loading of the saw chain in the area of ​​each cutting link. It has now been shown that a longer saw chain service life can be achieved by differently designed end faces of a rivet head.

[0021] Advantageously, the second end face has the recess, and the first end face has no recess. However, it can also be provided that the two end faces have differently shaped recesses.

[0022] Advantageously, the first end face is formed on a first rivet head and the second end face on a second rivet head. The rivet heads advantageously each protrude beyond the outer surface of the associated connecting link. The height of the second rivet head measured in the direction of the rivet bolt axis is advantageously greater than the height of the first rivet head measured in the direction of the rivet bolt axis. In an advantageous design, the two rivet heads therefore have different heights. The heights of the rivet heads are measured relative to the plane of the outer surface of the associated connecting link. Particularly advantageous is the second rivet head with the greater height, the rivet head whose end face has the recess, and the first rivet head with the lower height, which does not have a recess.

[0023] In a preferred design, the first end face is convex.

[0024] In an advantageous design, the curvature of the first end face in the diameter range of the recess base is mirror-symmetrical to the curvature of the recess base in the same diameter range on the second end face. As a result, similar or approximately equal forces are introduced into the rivet bolt on both end faces in the diameter range in which a recess base is arranged on one end face.

[0025] The difference between the distance between the first end face at the intersection of the rivet bolt axis and the first end face to the center plane and the distance between the second end face at the intersection of the rivet bolt axis and the second end face to the center plane is advantageously less than 0.3 mm. The distances are preferably approximately equal. The difference between the distances is in particular less than 0.1 mm. Particularly preferably, the distances are equal within the manufacturing tolerances. The centers of the end face of a rivet are advantageously approximately at the same distance from the center plane.

[0026] Advantageously, all faces on one side of the saw chain are first faces, and all faces on an opposite, second side of the chain are second faces. It has proven particularly preferable for a saw chain operated with a hand-held chainsaw if the faces on a right-hand side of the chain, positioned to the right in the running direction, are first faces, and the faces on a left-hand side of the chain, positioned to the left in the running direction, are second faces.

[0027] An embodiment of the invention is explained below with reference to the drawings. They show: Fig. 1 and 2perspective views of an embodiment of a saw chain, Fig. 3 and 4side views of the saw chain from the Fig. 1 und 2 , Fig. 5a section along the line VV in Fig. 3 and Fig. 6 the detail VI from Fig. 5 in enlarged view.

[0028] Fig. 1 shows a perspective view of a saw chain 1. The saw chain 1 moves in a running direction 10 during operation. Fig. 1 shows a view of a right side of the chain 15. Fig. 2 shows a view of the opposite, left-hand side of the chain 16. The saw chain comprises connecting links 2 and drive links 3. The drive links 3 each have a drive attachment 9, which is designed to engage with a guide bar of a chainsaw. The saw chain 1 can be driven at the drive attachment 9, for example, via a drive pinion. The drive links 3 each have two rivet openings 12. Rivet bolts 4 protrude through the rivet openings 12 and pivotally connect the drive links 3 to the connecting links 2. Each rivet bolt 3 protrudes through two connecting links 2 and a drive link 3 arranged between the two connecting links 2.

[0029] The connecting links 2 are partially designed as cutting links 5, 6. Right cutting links 5 are arranged on the right side of the chain 15 and left cutting links 6 on the left side of the chain 16 ( Fig. 2 ). The cutting members 5, 6 each have a cutting section 7. The cutting section 7 can have a geometrically defined or a geometrically indeterminate cutting edge geometry. In the exemplary embodiment, the cutting section 7 is provided for machining a workpiece, in particular made of wood. The cutting section 7 has a geometrically defined cutting edge geometry. In an alternative embodiment, it can be provided that the cutting section 7 is designed for grinding a workpiece, in particular a workpiece made of concrete. The cutting edges of the cutting section 7 can, for example, be formed from a large number of abrasive grains, for example diamond. The geometry of the cutting edges is geometrically indeterminate in this case.

[0030] In the exemplary embodiment, a depth limiter 8 is arranged upstream of each cutting section 7. In the exemplary embodiment, the depth limiter 8 and the subsequent cutting section 7 are arranged on the same cutting element 5, 6.

[0031] The designations "right side of the chain 15" and "left side of the chain 16" refer to a view of the saw chain from above onto the cutting sections 7, i.e. from the cutting sections 7 in the direction of the drive lugs 9. In this viewing direction, the right side of the chain 15 is arranged on the right and the left side of the chain 16 is arranged on the left in the running direction.

[0032] As the Fig. 1 und 2 also show, in the running direction 10, a pair of connecting links 2 in which one connecting link 2 is designed as a left cutting link 6 is followed by a pair of connecting links 2 without a cutting section, and this is followed by a pair of connecting links 2 in which one connecting link 2 is designed as a right cutting link 5. Pairs of connecting links 2 with a cutting section alternate in the running direction 10 with pairs of connecting links 2 without a cutting section 7. Right cutting links 5 and left cutting links 6 alternate in the running direction 10.

[0033] A different design of the saw chain 1 may also be advantageous.

[0034] As the Fig. 3 und 4 show, the saw chain 10 has a longitudinal center axis 17. With an elongated saw chain 1, the longitudinal center axis 17 runs parallel to the running direction 10. Each rivet bolt 4 has a rivet bolt axis 18. The rivet bolt axis 18 corresponds to the pivot axis around which the rivet bolt 4 articulates the connecting links 2 to the drive link 3 arranged therebetween. If a section of the saw chain 1 is elongated, all rivet bolt axes 18 of this elongated section of the saw chain 1 intersect the longitudinal center axis 17 of the saw chain 1.

[0035] How Fig. 3 As shown, the rivet bolts 4 on the right side of the chain 15 have end faces 33. In the exemplary embodiment, the end faces 33 of all rivet bolts 4 on the right side of the chain 15 are formed without recesses. In the exemplary embodiment, the end faces 33 are formed on the right rivet heads 13.

[0036] How Fig. 4 As shown, the rivet bolts 4 in the exemplary embodiment form left rivet heads 14 on the left side of the chain 16. The rivet bolts 4 have a second end face 34 on the left side of the chain 16. In the exemplary embodiment, all rivet bolts 4 have a recess 20 on the second end face 34, which will be described in more detail below.

[0037] At the rivet heads 13, 14, the rivet bolts 4 have an enlarged outer diameter b ( Fig. 6 ). The rivet heads 13, 14 each protrude beyond an outer surface 23 of the associated connecting link 2. In an alternative embodiment, one or both rivet heads 13, 14 can be flush with the outer surface 23 of the associated connecting link 2. It can be provided that one or both rivet heads 13, 14 are set back from the outer surface 23 of the associated connecting link 2.

[0038] Fig. 5 shows a section through a rivet bolt 4. One of the connecting links 2 in the sectional view of Fig. 5 is a right cutting link 5. The saw chain 1 has a center plane 19. The center plane 19 runs perpendicular to the rivet bolt axes 18 and centrally through the drive links 3. The center plane 19 is therefore parallel to the plane of the drive links 3. The center plane 19 and the rivet bolt axes 18 intersect in the longitudinal center axis 17 when the saw chain 1 is stretched. As Fig. 5 As also shown, the connecting links have rivet openings 11. The rivet bolt 4 protrudes through the rivet opening 12 of the drive link 3 as well as through the rivet openings 11 of the two connecting links 2 arranged on either side of the drive link 3. The rivet openings 11 in the connecting links 2 are smaller than the rivet opening 12 in the drive link 3. The rivet bolt 4 has a collar 24 at which the outer diameter of the rivet bolt 4 is enlarged. The collar 24 extends into the rivet opening 12 of the drive link 3. The collar 24 does not protrude into the rivet openings 11 of the adjacent connecting links 2.

[0039] How Fig. 6 shows, the rivet bolt 4 has a core diameter d. The diameter of the rivet openings 11 of the connecting links 2 corresponds approximately to the core diameter d. In the exemplary embodiment, the rivet bolt 4 has a circular cross-section. The rivet bolt 4 is rotationally symmetrical to the rivet bolt axis 18. A non-rotationally symmetrical design of the rivet bolt 4, in particular of sections of the rivet bolt 4, can also be advantageous. The rivet bolt 4 has a diameter i at the collar 24. The diameter i is larger than the core diameter d. The diameters of the rivet openings 11 and 12 are matched to the core diameter d and the diameter i at the collar 24. The diameter of the rivet opening 11 is smaller than the diameter i at the collar 24, so that the collar 24 cannot protrude into the rivet openings 11 of the connecting links 2.

[0040] How Fig. 6 As shown, the rivet bolt 4 is formed as a solid body. The rivet bolt 4 is therefore not a hollow rivet. The rivet bolt 4 extends through the rivet openings 11 and 12 and, in the exemplary embodiment, is formed separately from both connecting links 2 and the drive link 3. The rivet bolt 4 is therefore not a rivet element that is molded onto a connecting link 2, i.e., is formed in one piece with it. The rivet bolt 4 is formed on both end faces 33 and 34 during the manufacture of the saw chain 1. This firmly connects the rivet bolt 4 to the connecting links 2.

[0041] In an alternative embodiment, the rivet bolt 4 is formed integrally with the connecting link 2 on its first end face 33. The rivet bolt 4 is formed integrally with the adjacent connecting link 2 on the end face 33. On the opposite side, the rivet bolt 4 protrudes through the rivet opening 11 of the opposite connecting link 2. This connecting link 2 is formed separately from the rivet bolt 4 and connected to it by a riveting process. A rivet head 14 is arranged on this side of the rivet bolt 4. The recess 20 is arranged on the second end face 34. The recess 20 is provided on the rivet head 14, at which the rivet bolt 4 is connected to a connecting link 2 formed separately from the rivet bolt 4 by riveting. The recess 20 is arranged on the side of the rivet bolt 4 at which the rivet bolt 4 protrudes through a rivet opening 11 of a connecting link 2.The recess 20 allows the torsional strength of the rivet bolt 4 in the rivet opening 11 of the connecting link 2 to be influenced. One side of the rivet bolt 4 is formed integrally with a connecting link 2, and the other side of the rivet bolt 4 has the recess 20.

[0042] In the exemplary embodiment, the enlarged diameter b of the rivet heads 13 and 14 is larger than the core diameter d. The outer surfaces 23 of the connecting links 11 face away from the center plane 19. The rivet heads 13 and 14 protrude beyond the outer surface 23 of the adjacent connecting link 2. Adjacent to the outer surface 23, the connecting links 2 each have a chamfer 25. It can also be provided that only one of the connecting links 2 has a chamfer 25, or that the chamfers 25 of the two connecting links 2 are designed differently. The chamfers 25 have a largest outer diameter p adjacent to the outer surface 23. The diameter b of the rivet heads 13 and 14 is advantageously larger than the outer diameter p at the chamfer 25. The rivet heads 13 and 14 therefore completely cover the rivet openings 11 in the direction of the rivet bolt axis 18.The enlarged outer diameter b of the rivet head 13, 14 is advantageously at least 120% of the largest diameter p of the chamfer 25.

[0043] It is provided that at least one end face 33, 34 of the rivet bolt 4 has a recess 20. In the exemplary embodiment, a recess 20 is provided on the second end face 34. The first end face 33 does not have a recess 20. The recess 20 has a recess base 21 and a recess edge 22. The recess edge 22 encloses the recess base 21. The rivet bolt axis 18 intersects the recess base 21. In the exemplary embodiment, the recess base 21 and the recess edge 22 are rotationally symmetrical about the rivet bolt axis 18. However, an asymmetrical design to the rivet bolt axis 18 can also be provided.

[0044] The recess base 21 is the area of ​​the recess 20 in which a distance e of the recess base 21 to the center plane 19 does not increase at any point on the recess base 21 with increasing radial distance from the rivet bolt axis 18. The greatest distance e of the recess base 21 to the center plane 19 therefore also exists at least at the intersection point of the recess base 21 with the rivet bolt axis 18. The distance e is measured parallel to the rivet bolt axis 18. The intersection point of the recess base 21 with the rivet bolt axis 18 corresponds to the intersection point 27 of the second end face 34 with the rivet bolt axis 18. The recess base 21 has a greatest distance a from the rivet bolt axis 18. In the exemplary embodiment, the greatest distance a corresponds to half the diameter of the recess base 21. The greatest distance a is measured in the radial direction to the rivet bolt axis 18. The distance a corresponds to the maximum radial distance of the recess bottom 21 to the rivet bolt axis 18.The greatest distance a of the recess base 21 to the rivet bolt axis 18 corresponds to at least 30%, in particular at least 50%, of half the core diameter d of the rivet bolt 4. As a result, the recess base 21 offers a sufficiently large surface area to transmit forces during riveting into the rivet bolt 4 approximately in the direction of the rivet bolt axis 18. The greatest distance a of the recess base 21 to the rivet bolt axis 18 corresponds to a maximum of 100% of half the core diameter d of the rivet bolt 4. Accordingly, the recess base 21 does not extend in the radial direction to the rivet bolt axis 18 beyond a rivet bolt section 28 arranged in the rivet bolt opening 11 of the connecting link 2. The greatest distance a of the recess base 21 to the rivet bolt axis 18 corresponds to a maximum of 80% of half the core diameter d of the rivet bolt 4.

[0045] The greatest distance a of the recess base 21 to the rivet bolt axis 18 is advantageously at least 20%, in particular at least 40% of half the greatest diameter p of the chamfer 25.

[0046] It can be provided that the recess base 21 is partially or completely flat. This is Fig. 6 shown with a solid line. Alternatively, a convexly curved recess bottom 21' can be provided, which Fig. 6 is shown schematically with a dashed line. The curvature of the recess base 21' can have a very large radius. The radius with which the recess base 21' is curved at the intersection point 27 is advantageously larger than the core diameter d, in particular larger than the diameter b of the rivet head 14.

[0047] The recess edge 22 has a distance q from the center plane 19, which increases radially outwards from the recess bottom 21. In Fig. 6 The distance q is schematically shown for a central region of the recess edge 22. The distance q is measured parallel to the rivet bolt axis 18.

[0048] The recess 20 has a greatest distance c from the rivet bolt axis 18. In a symmetrical design, the greatest distance c corresponds to half the diameter of the recess 20. The greatest distance c of the recess 20 from the rivet bolt axis 18 advantageously corresponds to at least 110% of the greatest distance a of the recess base 21 from the rivet bolt axis 18. The greatest distance c of the recess 20 from the rivet bolt axis 18 advantageously corresponds to 70% to 120% of half the core diameter d of the rivet bolt 4. Half the core diameter d corresponds to the core radius d / 2. The recess 20 advantageously projects in the radial direction to the rivet bolt axis 18 in the direction of view of the rivet bolt axis 18 beyond the rivet bolt section 28 in which the core diameter d is measured. Preferably, half the enlarged outer diameter b of the rivet head 14 is 1.5 times to 3.5 times, in particular 2 times to 3.5 times the largest distance a.

[0049] The left rivet head 14 has a height h measured parallel to the rivet bolt axis 18. The height h is advantageously greater than a depth f of the recess 20 measured parallel to the rivet bolt axis 18. The depth f is in particular less than 50%, in particular less than 30% of the height h. The depth f of the recess 20 is advantageously smaller than the greatest distance a of the recess base 21 from the rivet bolt axis 18. Preferably, the depth f is less than 40%, in particular less than 30% of the greatest distance a.

[0050] The connecting link 2 has a thickness m measured parallel to the rivet bolt axis 18. The chamfer 25 has a depth k measured in the same direction. The depth k is advantageously at most 30%, in particular at most 20%, of the thickness m of the connecting link 2.

[0051] In the exemplary embodiment, the two rivet heads 13 and 14 are designed differently. The right rivet head 13 does not have a recess 20 in the exemplary embodiment. The end face 33 intersects the rivet bolt axis 18 at an intersection point 26. The end face 33 is at a distance n from the center plane 19. Starting from the intersection point 26, the distance n decreases with increasing radial distance from the rivet bolt axis 18. In Fig. 6 a distance n near the rivet bolt axis 18 is shown as an example. The diameters b of both rivet heads 13 and 14 are the same in the exemplary embodiment. The right rivet head 13 has a height g, which is measured parallel to the rivet bolt axis 18. In the exemplary embodiment, the height g of the right rivet head 13 is smaller than the height h of the left rivet head 14, which has the recess 20. The first end face 33 is convex. The curvature of the first end face 33 in the diameter range of the recess base 21' is mirror-symmetrical to the curvature of the recess base 21' in the same diameter range on the second end face 34. The curvature of the recess base 21' is in Fig. 6 Exaggerated for clarity. In fact, the curved depression floor is 21' flatter than shown.

[0052] The distance n of the intersection point 26 on the first end face 33 and the distance e of the intersection point 27 on the second end face 34 from the center plane 17 are preferably approximately equal. The difference between the distances n and e at the intersection points 26 and 27 is advantageously less than 0.3 mm, in particular less than 0.1 mm. The distances n and e are preferably equal within the manufacturing tolerances. The above-described design of rivet bolts 4 can also be provided for differently constructed saw chains 1 within the scope of claims 1 and 10.

Claims

1. Saw chain comprising connecting links (2) and drive links (3), which are connected to one another in an articulated manner about rivet bolt axes (18) by means of rivet bolts (4), wherein the rivet bolts (4) protrude through at least one rivet opening (11) of at least one connecting link (2) and a rivet opening (12) of a drive link (3) disposed between two connecting links (2), wherein the saw chain (1) has a central plane (19) which extends perpendicularly to the rivet bolt axes (18) and centrically through the drive links (3), wherein the connecting links (2) are partially formed as cutting links (5, 6) and have a cutting portion (7), wherein at least one rivet bolt (4) has a recess (20) on at least one end face (34), characterized in that the recess (20) has a recess edge (22), wherein the spacing (q) of the recess edge (22) from the central plane (19) of the saw chain (1) increases with increasing radial spacing from the rivet bolt axis (18), in that the recess (20) has a recess bottom (21, 21') enclosed by the recess edge (22), wherein the spacing (e) of the recess bottom (21, 21') from the central plane (19) of the saw chain (1) at no point in the recess bottom (21, 21') increases with increasing radial spacing from the rivet bolt axis (18), and in that the largest spacing (a) of the recess bottom (21, 21') from the rivet bolt axis (18) corresponds to 30% to 100% of half the core diameter (d) of the rivet bolt (4).

2. Saw chain according to Claim 1, characterized in that the recess bottom (21') is of a convexly curved design.

3. Saw chain according to Claim 1 or 2, characterized in that the largest spacing (a) of the recess bottom (21, 21') from the rivet bolt axis (18) corresponds to a maximum of 80% of half the core diameter (d) of the rivet bolt (4).

4. Saw chain according to one of Claims 1 to 3, characterized in that the largest spacing (c) of the recess (20) from the rivet bolt axis (18) corresponds to at least 110% of the largest spacing (a) of the recess bottom (21) from the rivet bolt axis (18).

5. Saw chain according to one of Claims 1 to 4, characterized in that the depth (f) of the recess (20) measured parallel to the rivet bolt axis (18) is smaller than the largest spacing (a) of the recess bottom (21, 21') from the rivet bolt axis (18), in particular is less than 40%, advantageously less than 30%, of the largest spacing (a).

6. Saw chain according to one of Claims 1 to 5, characterized in that at least one end face (33, 34) of a rivet bolt (4) is formed on a rivet head (13, 14) with an enlarged outer diameter (b) which projects beyond the outer surface (23) of the assigned connecting link (2).

7. Saw chain according to Claim 6, characterized in that the ratio of half the enlarged outer diameter (b) of the rivet head (14) to the largest spacing (a) of the recess bottom (21, 21') from the rivet bolt axis (18) is from 1.5 to 3.5.

8. Saw chain according to one of Claims 1 to 7, characterized in that the connecting link (2) at the rivet opening (11) has a chamfer (25), the depth (k) of the latter being at most 30%, in particular at most 20%, of the thickness (m) of the connecting link (2).

9. Saw chain according to one of Claims 1 to 8, characterized in that the rivet bolt (4) has a collar (24) which is disposed in the rivet opening (12) of the drive link (3) and does not protrude into the rivet openings (11) of the connecting links (2).

10. Saw chain according to one of Claims 1 to 9, or according to the preamble of Claim 1, characterized in that the rivet bolt (4) is formed as a solid body and in that the rivet bolt (4) has a first end face (33) and a second end face (34), which are of different designs.

11. Saw chain according to Claim 9, characterized in that the second end face (34) has the recess (20), and the first end face (33) has no recess (20).

12. Saw chain according to Claim 10 or 11, characterized in that the first end face (33) is formed on a first rivet head (13), and the second end face (34) is formed on a second rivet head (14), and in that the height (h) of the second rivet head (14) measured in the direction of the rivet bolt axis (18) is greater than the height (g) of the first rivet head (13) measured in the direction of the rivet bolt axis (18).

13. Saw chain according to one of Claims 10 to 12, characterized in that the first end face (33) is of a convex design.

14. Saw chain according to one of Claims 10 to 13, characterized in that the curvature of the first end face (33) in the diameter region of the recess bottom (21') is mirror symmetrical to the curvature of the recess bottom (21') in the same diameter region on the second end face (34).

15. Saw chain according to one of Claims 10 to 14, characterized in that the difference between the spacing (n) of the first end face (33) at the point of intersection (26) of the rivet bolt axis (18) and the first end face (33) from the central plane (19) and the spacing (e) of the second end face (34) at the point of intersection (27) of the rivet bolt axis (18) and the second end face (34) from the central plane (19), is less than 0.3 mm.

16. Saw chain according to one of Claims 10 to 15, characterized in that at least one end face (33, 34) of the rivet bolt (4) is formed on a rivet head (13, 14) with an enlarged outer diameter (b) which projects beyond the outer surface (23) of the assigned connecting link (2).