US3581783A

US3581783A - Lubricating means for chain saw bar

Info

Publication number: US3581783A
Application number: US360710*[A
Authority: US
Inventors: Karl Lennart Sandin
Original assignee: Sandvik AB
Current assignee: Santrade Ltd
Priority date: 1968-04-30
Filing date: 1969-09-24
Publication date: 1971-06-01
Anticipated expiration: 1988-06-01
Also published as: SE321072C; SE321072B

Abstract

An arrangement is disclosed for lubricating the guide bar and chain of a chain saw. The guide bar has an oil hole extending to the groove in which the tangs of the center links slide. The general depth of the groove is greater than the tang length so that the ends of the tangs move along a path spaced from the bottom of the groove. The oil hole is at a level above the path of the bottom ends of the tangs, and the bottom of the groove is shallow at that zone. Hence, as the oil enters, it is retained at that level and is picked up and carried away by the tangs.

Description

United States Patent Inventor Karl Lennart Sandin Gavle, Sweden Appl. No. 860,710 Filcd Sept. 24, 1969 Patented June I, 1971 Assignee Sandvikens Jernverks Aktiebolag Sandviken, Sweden Priority Sept. 30, 1968 Sweden 13155 LUBRICATING MEANS FOR CHAIN SAW BAR 8 Claims, 3 Drawing Figs.

[56] References Cited UNITED STATES PATENTS 2,765,823 10/1956 Kneifl 143/32 3,292,670 12/1966 Ratz et a1 143/32 FOREIGN PATENTS 812,471 8/1951 Germany 143/32-10 Primary Examiner-Donald R. Schran Atl0rneyCurtis, Morris & Safford ABSTRACT: An arrangement is disclosed for lubricating the guide bar and chain of a chain saw. The guide bar has an oil hole extending to the groove in which the tangs of the center links slide. The general depth of the groove is greater than the tang length so that the ends of the tangs move along a path spaced from the bottom of the groove. The oil hole is at a level above the path of the bottom ends of the tangs, and the bottom of the groove is shallow at that zone. Hence, as the oil enters, it is retained at that level and is picked up and carried away by the tangs.

PATENTEI] JUN Han 8.581; 783

Fig.3

LUBRICATING MEANS FOR CHAIN SAW BAR The present invention relates to a chain saw guide bar having grooves along its longitudinal edges for guiding the saw chain, and having a lubricating hole in the wall of the groove for supplying oil to the chain. Such constructions have previously had the disadvantage that the hole easily becomes clogged by sawdust collecting in the groove. The present in vention is an improvement which overcomes the difficulties that have been encountered in maintaining proper lubrication of saw chains and guide bar assemblies. Accordingly, it is an object of the present invention to'provide improved chain saw constructions It is a further object to provide improved guide bars which ensure the proper lubricating of saw chains operating in combination therewith. Another object is to provide for the above with structures which are simple, sturdy, dependable and adaptable to various conditions of operation and use. These and other objections will be in part obvious and in part pointed out below.

In accordance with the present invention, a chain saw of a standard known type is provided with a special guide bar. The drawings of the present application show the guide bar and saw chain, with the guide bar having an oil hole in the wall of the groove at the level of the path of the tangs of the center links, and the groove is shallow adjacent that hole. The arrangement is such that oil entering the hole is maintained at that level and is picked up by the tangs of the center links, so that each tang carries a film of oil with it longitudinal along the groove. The raised bottom wall of the groove at the shallow portion presents an elongated, smooth curve and the passing tangs prevent the accumulation of sawdust adjacent the oil hole. Hence, the oil hole does not become plugged and the disadvantages of the prior arrangements are avoided. IN THE DRAWINGS:

FIG. 1 is a sectional view of a guide bar and a portion of an endless saw chain, constitutes one embodiment of the invention; and,

FIGS. 2 and 3 are similar views showing other embodiments of the guide bar.

The guide bar of FIG. 1 comprises a center plate positioned between two sideplates 11, only one of which is shown and all of the plates are welded together. Sideplates 11 are wider than center plate 10 so that at each side of the guide bar the edges 16 of the sideplates are above the edge 22 of the center plate, and the edges are parallel. Hence, there is a groove 12 along each side of the guide bar having a bottom surface 22 formed by the edge of the center plate.

The guide bar is mounted as an operating component of a chain saw not shown having a driving sprocket at the arcuate right-hand end of the guide bar. A portion of an endless saw chain is shown, which is mounted on the driving sprocket and the guide bar, and has

side links

14 and 15 and center links 17.

Side links

14 and 15 rest upon the longitudinal edges 16 of the side plates 11, and center links.13 are the driving links which have tangs or teeth 17 which are engaged by the driving sprocket and which project into groove 12 as they move along the guide bar. Hence, tangs 17 guide the chain saw, while the side links provide the support in the general plan of the guide bar. Links 15 are cutter links of known construction, and the chain moves toward the left at the top of FIG. 1 and returns to the driving sprocket at the bottom of FIG. I. There is a tendency for sawdust to accumulate in the groove. and the tangs carry it away in the upper portion 20. However, it tends to accumulate in the bottom portion 21 of the groove which is below the path of the bottom or lower ends of tangs 17, represented by the broken line 19.

A lubricating opening or oil hole 23 is provided in the one sideplate 11 which opens into groove 12 sothat oil can be delivered to the saw chain. The other sideplate has no such oil hole, so that. oil entering the hole is retained in groove 12. The center of the oil hole has its center slightly above line 19 and its upper edge is spaced from the upper edge 16 of the sideplate a distance which is slightly less than the diameter of the hole. Adjacent oil hole 23, center plate 10 has a portion 30 which extends upwardly from the bottom of the groove to substantially the level of line 19 and thus slightly above the bottom edge of hole 23. Portion 30 represents a surface which is a segment of a cylinder and produces a shallow zone in the groove, longitudinally in both directions from hole 23. Hence, when oil is delivered through oil hole 23, it flows on to the top surface 29 of portion 30. As tangs 17 move from right to left passed surface 29, the lower portion of each tang is thoroughly coated by the oil and the oil is carried away along the path of the chain. It has been found that the oil thoroughly lubricates the chain parts, and is carried in a very efficient and dependable manner around the guide bar so as to coat all of the relatively moving surfaces along the path of the chain. Also, the oil does not tend to accumulate in the bottom of the grooves, and there is a reduced tendency for the oil to be absorbed by the sawdust and that has important attended advantages. The raised portion 30 prevents the accumulation-of sawdust at the oil hole thus preventing the oil hole from becoming clogged.

Oil hole 23 is circular in cross section and is generally above the top surface 29 of portion 30. However, during use the top edges 16 of sideplates 11 tend to wear down so that path 19 of the lower ends of tangs 17 is closer to the bottom surface 22 of groove 12. During such wear, the bottom ends of the tangs also wear away the top of portion 29 so that to expose the entire oil hole. However, even under extreme conditions of wear the top surface 29 of portion 30 is above the level represented by the broken line 22a, which is an extension of the adjacent bottom surface 22 of groove 12. In this embodiment, center plate 10 is of relatively soft metal so that it is readily worn away by the bottoms of the tangs.

In the embodiment of FIG. 2, a separate insert 31 is provided in place of the portion 30 of FIG. 1. Insert 31 has an anchor portion 32 which mates with an anchor groove in the center plate 10. In this embodiment insert 31 is a plastic and it wears away readily so that its top surface is always at the level 19 of the bottom ends of the tangs. However, the plastic yields under pressure and it maybe extended to the right along the groove 12.

In the embodiment of FIG. 3, and insert 33 of aluminum wire is provided in place of raised portion 30 of FIG. 1. The ends 34 of insert 33 are formed into hooks which are anchored in bores in the edge of center plate 10. The center of insert 33 is bowed upwardly so that it has a spring action. Here again the top surface of the insert may be worn away by the bottom of the tangs, but the insert is also yieldable so that it can be pushed downwardly by the tangs. The insert may be of some other material than aluminum that is soft enough to be worn away by the tangs or is resilient enough to yield. In the embodiment of FIGS. 2 and 3, the operation is generally as described in connection with FIG. 1. It is understood that the oil hole may be oblong under some conditions of use.

Iclaim:

I. In a chain saw, the combination of, a guide bar having a pair of sideplates- .and a center plate rigidly mounted therebetween, each of said plates having longitudinal side edges extending along the opposite sides of the longitudinal centerline of the guide bar, and an endless saw chain mounted upon said guide bar and comprising a series of interconnected side links and center links, said edges of said sideplates upon each side of the guide bar presenting supporting surfaces in the single plane upon which the side links of the chain saw move along and are supported, each side edge of said .center plate being spaced inwardly with respect to the adjacent side edges of said sideplates whereby a groove is provided said center links having tangs which are positioned within and move along said groove from a driving sprocket to the nose end of the guide bar, said groove having a depth which'is generally greater than the distance of said tangs extend therein whereby the bottom ends of said tangs move along a path which is spaced from the bottom of said groove, said guide bar including a lubricating hole in one of said sideplates extending to said groove to deliver lubricant at a level in said groove adjacent the lower portion of the tangs and said groove being shallow adjacent said lubricating hole with the bottom of the groove being formed by retainer means presenting a surface which is at substantially the level of the path of the lower ends of the tangs whereby lubricant entering said hole is delivered to said surface and is picked up and carried away by the movement of the tangs past said hole.

2. The combination described in claim 1 wherein said retainer means is integral with said center plate.

3. The combination as described in claim 1 wherein said retainer means is of material which is worn away when contacted by the bottom ends of said tangs.

4. The combination described in claim 1 wherein said retainer means comprises a insert member fixed to said plates.

5. The combination described in claim 4 wherein said insert member includes an anchor portion and said center plate has an anchor recess in which said anchor portion is rested.

6. The combination as described in claim I wherein said retainer portion comprises a metal strip having central bowed and hooked ends and wherein said center plate has recess in which said ends are positioned.

7. The combination as described in claim 2 wherein said retainer means is nonmetallic.

8. In a guide bar for a chain saw, the combination of, a pair of sideplates and a center plate rigidly mounted therebetween, each of said plates having longitudinal side edges extending along the opposite sides of the longitudinal centerline of the guide bar, said edges of said sideplates upon each side of the guide bar presenting supporting surfaces in the single plane upon which the side links of the chain saw move along and are supported, each side edge of said center plate being spaced inwardly with respect to the adjacent side edges of said sideplates whereby a groove is provided within which the tangs of the center links of the saw chain are positioned said guide bar including a lubricating hole in one of said sideplates extending to said groove to deliver lubricant at a level in said groove adjacent the lower portion of the tangs and said groove being shallow adjacent said lubricating hole with the bottom of the groove being formed by a surface which is at substantially the level of the path of the lower ends of the tangs whereby lubricant entering said hole is delivered to said surface and is picked up and carried away by the movement of the tangs past said hole.

Claims

1. In a chain saw, the combination of, a guide bar having a pair of sideplates and a center plate rigidly mounted therebetween, each of said plates having longitudinal side edges extending along the opposite sides of the longitudinal centerline of the guide bar, and an endless saw chain mounted upon said guide bar and comprising a series of interconnected side links and center links, said edges of said sideplates upon each side of the guide bar presenting supporting surfaces in the single plane upon which the side links of the chain saw move along and are supported, each side edge of said center plate being spaced inwardly with respect to the adjacent side edges of said sideplates whereby a groove is provided said center links having tangs which are positioned within and move along said groove from a driving sprocket to the nose end of the guide bar, said groove having a depth which is generally greater than the distance of said tangs extend therein whereby the bottom ends of said tangs move along a path which is spaced from the bottom of said groove, said guide bar including a lubricating hole in one of said sideplates extending to said groove to deliver lubricant at a level in said groove adjacent the lower portion of the tangs and said groove being shallow adjacent said lubricating hole with the bottom of the groove being formed by retainer means presenting a surface which is at substantially the level of the path of the lower ends of the tangs whereby lubricant entering said hole is delivered to said surface and is picked up and carried away by the movement of the tangs past said hole.

6. The combination as described in claim 1 wherein said retainer portion comprises a metal strip having central bowed and hooked ends and wherein said center plate has recess in which said ends are positioned.