A hub device for a pair of saw blades, which saw blades are arranged to rotate about the same rotational axis and in an opposite direction to one another. The hub device includes a first blade adapter, which has a support surface for the first saw blade, and a second blade adapter, which has a support surface for the second saw blade and a central fastener for a blade lock, which is arranged to secure both blades. The support surface of the first blade adapter is designed to engage the first saw blade. The support surface of the second blade adapter is designed to engage the second saw blade.
1. A hub device arrangement comprising:
a first blade configured to rotate about a rotational axis in a first direction, the first blade having a back side and an opposite front side;
a second blade configured to rotate about the rotational axis in a second direction opposite to the first direction, the second blade having a back side and an opposite front side;
wherein each of the first and the second blades has a blade body and cutting elements provided along the periphery of the blade body;
wherein the cutting elements of the first and the second blades are configured to run in parallel with each other during rotation, and spaced apart by a distance determined by a spacer provided on at least one of the blade bodies; and
wherein the front side of the first blade faces towards the back side of the second blade;
a first blade adapter including
a support surface for the back side of the first blade,
a centering flange protruding from the support surface, the centering flange engaging a centering hole provided in the first blade, and
protruding drive pegs engaging drive peg notches that surround the centering hole of the first blade; and
a second blade adapter including
a support surface for the back side of the second blade, and
a central fastener for receiving a blade lock to secure the first and the second blades;
wherein the support surface of the second blade adapter has at least three ridges situated around the rotational axis, the ridges engage with corresponding notches provided in the second blade, and the ridges have a height that exceeds a thickness of the main body of the second blade; and
wherein the blade lock has a circumferential ring surface that abuts against the ridges of the second blade adapter, such that the second blade has limited axial mobility between the support surface of the second blade adapter and the circumferential ring surface of the blade lock, the limited axial mobility being determined by the difference between the height of the ridges and the thickness of the blade body of the second blade.
2. The hub device arrangement according to claim 1 , wherein the second blade adapter is axially mounted relative to the first blade adapter, such that the distance between the blade bodies of the first and the second blades is less at the centers of the blade bodies than at the peripheries of the blade bodies;
wherein the distance between the blade bodies at the peripheries of the blade bodies is determined by the spacer; and
wherein the second blade adapter is threaded onto an inner shaft.
3. The hub device arrangement according to claim 2 , wherein the distance between the blade bodies at the centers of the blade bodies is 0.02 to 0.10 mm less than at the peripheries of the blade bodies where the spacer is provided.
4. The hub device arrangement according to claim 1 , wherein the blade lock is shaped as a screw nut with a neck passing through a corresponding centering hole provided in the second blade.
5. The hub device arrangement according to claim 1 , wherein the drive pegs of the first blade adapter protrude from the support surface a distance that is less than the thickness of the blade body of the first blade.