Saw chain drive link with tail
View Patent ↗A saw chain for a saw is disclosed. Embodiments include a drive link that may be used in a saw chain, wherein the drive link includes a tail and a concavity that complements a depth gauge of a trailing cutting link, reducing and/or minimizing the drive link's protrusion into a gullet space of the cutting link. Embodiments of the invention may help improve cutting performance and further help reduce kickback potential.
1. A saw chain comprising:
a cutting link having a forward cutting link rivet hole and a rearward cutting link rivet hole, and further having an upper cutting edge disposed at a first height relative to a guide bar rail and a depth gauge having a rear face opposing the cutting edge and an upper surface disposed generally at or below the first height, a gullet formed between the cutting edge and the depth gauge;
a drive link having a forward drive link rivet hole and a rearward drive link rivet hole, the drive link coupled to the cutting link via a rivet engaging the forward cutting link rivet hole and the rearward drive link rivet hole, wherein in a first position a longitudinal first centerline passes through centers of the rivet holes and the rivet, the rivet further including a second centerline perpendicular to the longitudinal first centerline and generally coplanar with the drive link,
the drive link including a top edge having a rearmost portion that is generally the closest point to the upper cutting edge of the cutting link and disposed a first distance from the second centerline;
a tail extension distance defined by the distance between the top edge rearmost portion and the depth gauge rear face;
a trailing edge disposed generally below the top edge, a concavity formed between the top edge and the trailing edge, the concavity having a forward most portion disposed below the upper edge rearmost portion and a second distance from the perpendicular second centerline of the rivet, wherein the second distance is shorter than the first distance such that the forward most portion is disposed in front of the upper edge rearmost portion, thereby defining a concavity depth and forming a tail on the drive link;
wherein as the saw chain traverses a straight run of a guide bar the rearmost portion protrudes into the gullet the tail extension distance and the top edge is disposed generally at or below the upper surface of the depth gauge; and
wherein as the saw chain traverses a nose of the guide bar the position of the tail moves relative to the depth gauge.
2. The saw chain of claim 1 , wherein the rearmost portion does not move beyond the height of the depth gauge.
3. The saw chain of claim 1 , wherein the tail has a radial tail dimension substantially equal to the height of the depth gauge as measured from a common pivot point of the cutting link and the drive link.
4. The saw chain of claim 1 , wherein a gullet distance is defined between the rearmost portion and the upper cutting edge, and wherein the ratio of the tail extension distance to the gullet distance is substantially 0.06 to 0.43.
5. The saw chain of claim 1 , wherein the concavity has a concavity depth that is between 50% and 100% of a tail extension distance.
6. The saw chain of claim 1 , wherein the tail includes a tail angle of between 20 to 80 degrees where the tail angle is measured between the top edge and an upper edge of the concavity.
7. The saw chain of claim 1 , wherein the tail has a tail height that is in the range of 80 to 100 percent of a depth gauge height.
8. The saw chain of claim 1 , wherein the first distance in a range of approximately 0.06 to 0.15 inches.
9. The saw chain of claim 1 , wherein the concavity includes a concavity angle of between approximately 20 to 80 degrees.