Chainsaw guide bar nose assembly

Abstract

This invention relates to a nose assembly for a chainsaw guide bar for wood harvesting and a chainsaw guide bar having the same. The nose assembly (400) comprising: a pair of nose side plates (410, 420; 470); and a sprocket and bearing assembly adapted to be clamped between the pair of nose side plates (410, 420; 470) and comprising an idler sprocket (450); wherein at least one of the pair of the nose side plates (410, 420; 470) is provided at an inside surface thereof facing to the sprocket and bearing assembly with one or more lubricant conveying channels for lubricating the sprocket and bearing assembly. The chainsaw guide bars according to the present invention enable flow of lubricant to moving parts in order to reduce friction of these moving parts as a saw chain rotates though the guide bar.

Claims

1. A chainsaw guide bar comprising a guide bar body and a nose assembly, wherein the nose assembly comprising a pair of nose side plates used in a chainsaw guide bar, wherein at least one inside surface of each of the pair of nose side plates has one or more lubricant conveying channels; and a sprocket and bearing assembly adapted to be clamped between the pair of nose side plates and comprising a saw chain-rotatable idler sprocket; wherein the at least one inside surface of the pair of the nose side plates is disposed to face the sprocket and bearing assembly and is configured to provide lubricant via the one or more lubricant conveying channels to the sprocket and bearing assembly, and the nose assembly is detachably attached to the guide bar body, the one or more lubricant conveying channels defined on at least one inside surface of the pair of nose side plates are connected with a corresponding lubricant conveying channel defined in a periphery of the guide bar body.

2. The chainsaw guide bar according to claim 1, wherein each of the one or more lubricant conveying channels comprises a plurality of lubricant conveying grooves extended divergently towards the sprocket and bearing assembly.

3. The chainsaw guide bar according to claim 1, wherein one of the one or more lubricant conveying channels is a single curved lubricant conveying groove following having a spiral path.

4. The chainsaw guide bar according to claim 3, wherein the single curved lubricant conveying groove has one end thereof extending to a position corresponding to an inner circumferential edge of the idler sprocket.

5. The chainsaw guide bar according to claim 1, wherein the sprocket and bearing assembly further comprising: a central bearing member around which the idle sprocket mounted rotatably and is fixedly connected to and clamped between the pair of nose side plates; and a plurality of rollers disposed within an annular gap formed between the idler sprocket and the central bearing member.

6. The chainsaw guide bar according to claim 5, wherein the central bearing member is fixedly connected to and clamped between the pair of nose side plates.

7. A chainsaw guide bar comprising a guide bar body and a nose assembly, wherein the nose assembly is detachably attached to the guide bar body and comprises: a pair of nose side plates; and a sprocket and bearing assembly adapted to be clamped between the pair of nose side plates and comprising a saw chain-rotatable idler sprocket; wherein at least one inside surface of the pair of the nose side plates has one or more lubricant conveying channels and is disposed to face the sprocket and bearing assembly and is configured to provide lubricant via the one or more lubricant conveying channels to the sprocket and bearing assembly, and wherein the one or more lubricant conveying channels defined on the at least one inside surface of the pair of nose side plates of the nose assembly are connected with a corresponding lubricant conveying channel defined in a periphery of the guide bar body.

8. The chainsaw guide bar according to claim 7, wherein the at least one inside surface of the pair of the nose side plates has two groups of the lubricant conveying channels positioned symmetrically about a longitudinal axis of each of the pair of nose side plates.

9. The chainsaw guide bar according to claim 8, wherein each of the two groups of the lubricant conveying channels comprises a plurality of lubricant conveying grooves extended divergently towards the sprocket and bearing assembly.

10. The chainsaw guide bar according to claim 7, wherein one of the one or more lubricant conveying channels is a single curved lubricant conveying groove having a spiral path.

11. The chainsaw guide bar according to claim 10, wherein the single curved lubricant conveying groove has one end thereof extending to a position corresponding to an inner circumferential edge of the idler sprocket.

12. The chainsaw guide bar according to claim 7, wherein the sprocket and bearing assembly further comprising: a central bearing member around which the idle sprocket mounted rotatably; and a plurality of rollers disposed within an annular gap formed between the idler sprocket and the central bearing member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view of a chainsaw guide bar with replaceable nose assembly according to one embodiment of the invention.

(2) FIG. 2 is an exploded view in perspective of separated components of the chainsaw guide bar of FIG. 1.

(3) FIG. 3 is an elevation view of a chainsaw guide bar body prior to attachment thereto of the nose assembly of the invention.

(4) FIG. 3A is a section view along the line A-A of FIG. 3 of chainsaw guide bar body.

(5) FIG. 4 is an exploded view of components of a typical chainsaw chain.

(6) FIG. 5 is a view on an enlarged scale of a drive link of the chainsaw chain of FIG. 4.

(7) FIG. 6 is an exploded view of the components of the chainsaw guide bar nose assembly.

(8) FIG. 7 is an inside plan view of one of a pair of nose side plates.

(9) FIG. 8 is vertical section view along the line A-A of FIG. 7.

(10) FIG. 9 is that part on an enlarged scale of that part of the Section A-A of FIG. 8.

(11) FIG. 10 is an inside elevation of another embodiment of the invention and shows a nose side plate for the chainsaw guide bar nose assembly.

DETAILED DESCRIPTION OF THE INVENTION

(12) Referring to the accompanying drawings and firstly to the embodiment shown in FIG. 1, there is shown a chainsaw guide bar 100 with a replaceable nose assembly 400 attached thereto and which as shown in the exploded partial view of FIG. 2 comprises a guide bar body 200, a segment of chainsaw chain 300 and a nose assembly 400 with rivets 500 used to assemble the nose assembly 400 to the guide bar body 200.

(13) As shown in FIG. 3 the guide bar body 200 is provided at one (or right-hand shown) end with rivet holes 220 and at the other end with lubrication holes 210 and 211. FIG. 3A shows guide bar lubricant conveying grooves 230 and 240.

(14) FIGS. 4 and 5 show components of a chainsaw chain 300 suitable for use with the present invention and which comprise drive links 310, side plates (or joining links) 320, cutting links 330 and rivets 340 for assembling the chain.

(15) The exploded view of FIG. 6 shows components of the nose assembly which comprise a pair of side plates 410 and 420, a central bearing member (or bearing inner race) 430, a plurality of bearing rollers 440 and an idler (chain-driven) sprocket (or outer bearing race) 450. The components of the nose assembly are fastened together by rivets-eight of these being shown in FIG. 6 one such rivet being labeled 460 and for use with respect to the eight rivet holes shown in FIG. 7 and one such rivet hole being labeled 416.

(16) Referring again to FIG. 7 and to FIGS. 8 and 9, each of the nose side plates 410, 420 is provided at the inside surface thereof with two groups of the lubricant conveying channels positioned symmetrically about a longitudinal axis of the nose side plates 410, 420, and preferably, each of the pair of the lubricant-conveying channels comprises a plurality of lubricant conveying grooves 411, 412 extended divergently towards the sprocket and bearing assembly. FIG. 9 shows in greater detail the left side plate 410 shown in FIGS. 6 and 7, the left hand side plate is provided with a plurality of lubricant conveying grooves 411 to 414 which generally comprise a pair of elongate, curved, outer lubricant conveying grooves and a pair of short, linear inner lubricant conveying grooves. Each respective longer outer lubricant conveying groove is joined to a respective shorter inner lubricant conveying groove and both long and short-type lubricant conveying grooves may be considered as being mutually-divergent so as to create divergent streams of lubricant. One longer and outer lubricant conveying groove is adjacent one edge of the side plate and is labeled 411 and is joined by a shorter inner lubricant conveying groove labeled 412. The other longer and outer channel is adjacent one edge of the side plate and is labeled 413 and is joined by a shorter inner lubricant-delivering channel 414. FIG. 7 also shows a plurality of rivet holes used for assembling components of the invention; five rivet holes are used to assemble the guide bar body and nose assembly and these holes are typified by the one labeled 415. Eight rivet holes are used to assemble the components of the nose assembly, one of these being labeled 416.

(17) Referring to FIG. 10 there is shown an inside view of a different embodiment of the invention and which comprises a nose side plate 470 which has an inside surface of alternative configuration to that of the earlier embodiments and wherein each nose side plate may be of the same or different geometry. The inside surface of the nose side plate shown FIG. 10 has a single lubricant conveying groove 471 of curved configuration formed in the inside surface but, if desired, the lubricant conveying groove may follow a spiral path. FIG. 10 further shows in broken outline the inside diameter (inner circumferential edge) 472 and the outside diameter (outer circumferential edge) 473 respectively of the idler sprocket 450 shown in FIG. 9. Preferably, the lubricant conveying groove 471 with one end thereof extends to a position corresponding to an inner circumferential edge of the idler sprocket 450.

(18) The lubricant conveying groove of each nose side plate of the invention can be of any suitable geometry, path and depth.

(19) Whilst I have described in the foregoing embodiment a specific concept, forms and application of my invention, it will be understood by some persons skilled in this particular art that variations, modifications, substitutions and additions may be made without departing from the spirit and scope of this invention and I therefore do not wish to be understood as limiting ourselves to the precise terms used.