LINK FOR A CHAIN

Abstract: A link for a chain has a first planar portion (16;52) and a second portion integral with and disposed adjacent the first portion, the second portion being folded over to form a bight (30;14) having a pair of parallel, laterally-spaced opposed walls (34,36;68,70) defining a space therebetween and adapted to receive a first portion of an adjacent link.

Description: This invention relates to a link for a chain and to a chain incorporating the link, which may need not be a saw chain. A typical chain for a chain saw includes centre mounted drive links and a plurality of side links, some of the side links serving merely as tie straps, while others incorporate right-hand and left-hand cutters. The links are of different configurations and require many different manufacturing operations in their construction, so it would be advantageous to reduce the number of types of links in a chain. The invention accordingly provides a link for use on a chain comprising a plurality of articulated links, the link comprising a portion folded over to form a bight having a pair of parallel laterally-spaced opposed walls, the walls defining a space therebetween for receiving a portion of an adjacent link in the chain. The invention also provides a chain comprising at least two articulated links, each link comprising a planar first portion and a second portion integral with and disposed adjacent the first portion, the second portion being folded over to form a bight having a pair of parallel laterally-spaced opposed walls defining a space therebetween, the first portion of one of the two links being received within the second portion of the other of the two links, and pivot means interconnecting the first portion of the one link and the second portion fo the other link to permit articulation therebetween. The invention can thus provide a form of link for a chain which can serve as the only type of link in the chain or which can alternatively be used as one element in a chain that has a lesser number of different links than has heretofore been known. The invention can further provide a chain with fewer articulated joints between links than have been required heretofore, thereby to render the chain more stable during operation. The link of the invention can be readily arranged to run on a standard chain saw guide bar. The invention is further described below, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a chain incorporating links according to the invention; Fig. 2 is a perspective view of a chain link included in chain of Fig. 1; Fig. 3 is a side view of the chain link of Fig. 2; Fig. 4 is a plan view of the chain link of Fig. 2; Fig. 5 is a front end view of the chain link of Fig. 2; Fig. 6 is a plan view of a blank from which the chain link of Fig. 2 can be fabricated; Fig. 7 is a perspective view of a second chain link according to the present invention; Fig. 8 is a side view of the chain link of Fig. 7; Fig. 9 is a plan view of the chain link of Fig. 7; Fig. 10 is a front end view of the chain link of Fig. 7; and Fig. 11 is a plan view of a blank from which the chain link of Fig. 7 can be fabricated. In Figs. 1-6 of the drawings there is illustrated a chain link 14 connected into a length of chain 15. The link 14 comprises a first planar portion 16 having a depending sprocket-engageable drive tang 18 and a cutting tooth 20 projecting upwardly from its top edge 22. The planar portion 16 has a longitudinal axis 24 which is colinear with the longitudinal axis 25 of the chain 15. A transition portion 26 is disposed forwardly of the planar portion 16. The portion 26 is laterally offset from the portion 16 and is transitional between it and an adjacent integral second portion 28 which is disposed forwardly of portion 16 and constitutes the leading portion of the link. The portion 28 is folded over to form a bight 30 which extends upwardly in the rearward direction of the link and includes a pair of substantially parallel, laterally spaced, opposed walls 34 and 36 defining a space 38 between them. The transition portion 26 is laterally offset to an amount equal to the thickness of the material of the link 14 so that the axis 24 bisects the space 38. Because of this, the space 38 can receive the first planar portion 16 of a preceding link in the chain 15. Aligned rivet-receiving bores or openings 40 extend transversely through the walls 34 and 36 and a further rivet-receiving bore or opening 42 is provided in the portion 16. A single rivet 43 received in the openings 40 and 42 thus serves to connect the second portion 28 of each link 14 with the first portion 16 of an adjacent link to permit articulation therebetween. The upward extension of the bight 30 provides a sloping depth gauge 32 to limit the cut taken by the tooth 20 as the link 14 passes through a workpiece. The tang 18 is engaged by the drive sprocket of the chain saw (not shown) to drive the chain. The embodiment of the invention illustrated in Figs. 7-11 comprises a chain link 50 which is also suitable for use in the chain 15. The link 50 includes a first planar portion 52 having a depending sprocket-engageable drive tang 54, but has no cutting tooth on its top edge 56. The link 50 thus serves merely as a combined tie strap and drive link. Again, the planar portion 52 has a longitudinal axis 58 which is colinear with the longitudinal axis 25 of the chain 15, and again a transition portion 60 is disposed forwardly of planar portion 52. The portion 60 is laterally offset from portion 52 and provides a transition into an adjacent integral second portion 62 which is again disposed forwardly of first portion 52 and constitutes the leading portion of the link 50. The portion 62 is folded over to form a bight 64 and includes a pair of substantially parallel, laterally-spaced, opposed walls 68 and 70 which define a space 72 between them. The transition portion 60 is laterally offset by an amount equal to the thickness of the material of link 50, so that the axis 58 bisects the space 72. Because of this, the space 72 can receive the first planar portion 16 of a preceding link. Again, aligned rivet-receiving bores or openings 74 extend transversely through the walls 68, 70 and a further rivet-receiving bore or opening 76 is provided in the portion 52. A single rivet in the openings 74,76 can thus serve to connect the second portion 62 of the link 50 with the first portion 16 of an adjacent link to permit articulation therebetween. The tang 54 is engageable with the drive sprocket of the chain saw (not shown) to drive the chain. As is shown in Fig. 1, the chain 15 comprises left-hand cutting links 14 and mirror image right-hand cutting links 14a which alternate with the tie strap drive links 50. Alternatively, the links 14 and 14a can be pivotally connected together without links 50 to form a cutting chain, the links 14 and 14a being then the only elements of the chain. Also, whereas the cutting tooth 20 of the link 14 is illustrated as a typical hollow ground cutting tooth, the tooth may, if desired, comprise a top-sharpenable cutter tooth.

Claims: 1. A link for use in a chain comprising a plurality of articulated links, the link comprising a planar portion (16; 52) and an adjacent portion folded over to form a bight (30; 64) having a pair of parallel laterally-spaced opposed walls (34, 36; 68, 70), the walls defining a space therebetween for receiving a portion of an adjacent link in the chain. 2. A link as claimed in claim 1 wherein the planar portion (16; 52) has a longitudinal axis (24) which bisects the space between the walls of the folded portion. 3. A link as claimed in claim 2 having an opening (42; 76) in the planar portion and aligned openings (40; 74) in the walls of the folded portion for receiving therein pivots for connection of the link to adjacent links. 4. A link as claimed in claim 2 or 3 having a transition portion (26; 60) between the planar and folded portions, the transition portion being transversely offset with respect to the planar portion. 5. A link as claimed in claim 2, 3 or 4 for use in a saw chain wherein the planar portion comprises a depending sprocket-engageable drive tang (18; 54). 6. A link as claimed in claim 2, 3, 4 or 5 for use in a saw chain wherein the planar portion includes a cutting tooth (20) and the bight is shaped to function as a depth gauge (32) for the cutting tooth. 7. A chain including a link as claimed in any one of claims 2-6 wherein the longitudinal axis (24) of the planar portion of the link is colinear with the longitudinal axis of the chain (25). 8. A chain comprising at least two articulated links, each link comprising a planar first portion (16; 52) and a second portion integral with and disposed adjacent the first portion, the second portion being folded over to form a bight (30; 64) having a pair of parallel laterally-spaced opposed walls (34, 36; 68, 70) defining a space therebetween, the first portion of one of the two links being received within the second portion of the other of the two links, and pivot means (43) interconnecting the first portion of the one link and the second portion of the other link to permit articulation therebetween. 9. A chain as claimed in claim 8 wherein the pivot means comprises a rivet (43) received in a first rivet opening (42; 76) extending transversely through the first portion of the one link and in a second rivet opening (40; 74) extending transversely through the second portion of the other link, the first and second rivet openings being aligned when the links are assembled to receive the rivet. 10. A chain as claimed in claim 8 or 9, the chain being a saw chain, wherein the first portion (16; 52) of each link has a depending sprocket-engageable drive tang (18; 54), the bight (30; 14) being located at the outer side of the chain.

Inventors: HARFST, MICHAEL D.
Applicants: BLOUNT, INC.
Application year: 1988
Main classification: B27B33
IPC codes: B27B33