CHAIN SAW

Abstract

The invention relates to a chain saw comprising a guide bar (1) for guiding a saw chain, wherein the guide bar (1) comprises two side plates (2, 3) between which a sprocket wheel (4) is rotatable arranged, wherein the sprocket wheel (4) is supported in the guide bar (1) by means of a bearing (5) and wherein the bearing (5) is supplied by a lubricant by means of a lubrication system (6). To improve the lubrication of the bearing the invention proposes that the lubrication system (6) comprises a lubrication reservoir (7) which is in fluidic connection (8) with the bearing (5), wherein the lubrication reservoir (7) is sealed against the environment by at least one valve element (9).

Claims

1. Chain saw comprising a guide bar for guiding a saw chain, wherein the guide bar comprises two side plates between which a sprocket wheel is rotatably arranged, wherein the sprocket wheel is supported in the guide bar by a bearing and wherein the bearing is supplied with lubricant by a lubrication system, wherein the lubrication system comprises a lubrication reservoir which is in fluidic connection with the bearing, wherein the lubrication reservoir is sealed against the environment by a valve element.

2. The chain saw according to claim 1, characterized in that a shim is arranged between at least one of the side plates and the bearing, wherein the shim comprises the valve element.

3. The chain saw according to claim 2, characterized in that the shim consists of a sheet metal.

4. The chain saw according to claim 2, characterized in that the valve element is established in the shim by an incision machined into the shim.

5. The chain saw according to claim 4, characterized in that the incision has an arcuated shape, especially a semi-circular shape.

6. The chain saw according to claim 1, characterized in that the bearing is a roller bearing.

7. The chain saw according to claim 1, characterized in that the bearing has an inner bearing ring which serves as a hub for supporting the sprocket wheel.

8. The chain saw according to claim 7, characterized in that the lubrication reservoir is established by a recess in the inner bearing ring.

9. The chain according to claim 8, characterized in that the recess in the inner bearing ring is a centre bore in the inner bearing ring.

10. The chain saw according to claim 7, characterized in that the fluidic connection is established by at least one groove which is machined in the inner bearing ring.

11. The chain saw according to claim 10, characterized in that a plurality of grooves is machined in the inner bearing ring.

12. The chain saw according to claim 11, characterized in that the grooves are distributed equidistantly around the circumference of the inner bearing ring.

13. The chain saw according to claim 10, characterized in that the at least one groove extends radially in the inner bearing ring.

14. The chain saw according to claim 1, characterized in that the side plates, the shim and the inner bearing ring are connected with another by screws or rivets.

15. The chain saw according to claim 1, characterized in that at least one of the side plates has a lubrication bore which is arranged above the valve element.

Description

[0022] In the drawings an embodiment of the invention is depicted.

[0023] FIG. 1 shows a side view of a guide bar of a chain saw,

[0024] FIG. 2 shows a perspective view onto the axial end of the guide bar (see marking II in FIG. 1, which is enlarged in FIG. 2),

[0025] FIG. 3 shows an explosion view of the axial end of the guide bar according to FIG. 1,

[0026] FIG. 4 shows a perspective viewpartially brokenof the axial end of the guide bar in the mounted state and

[0027] FIG. 5 shows a perspective view of the axial end of the guide bar with one of the side bars demounted.

[0028] In FIG. 1 a guide bar 1 of a chain saw is shown. The axial end of the guide bar 1 is shown in an enlarged depiction in FIG. 2. As can be seen here the guide bar 1 has two side plates 2 and 3 which are kept on a certain distance from another. Between the side plates 2, 3 a sprocket wheel 4 is supported by a (not visible) bearing. The whole arrangement is fixed by a number of rivets 12.

[0029] The general design of such a guide bar is detailed explained in the above mentioned documents. Insofar, explicitly reference is made to those documents.

[0030] The details of the design according to the present invention become apparent from FIGS. 3, 4 and 5 where the guide bar 1 and more specifically its axial end is shown in perspective view.

[0031] Here, the bearing 5 can be seen which is a roller bearing in the present case with a plurality of rolling element 14. The rolling elements 14 are arranged around an inner bearing ring 11 which is functioning as a hub for the sprocket wheel 4.

[0032] To ensure proper lubrication conditions during use of the chain saw a lubrication system 6 is employed. By this the bearing 5 is provided with a lubricant which can be oil or grease.

[0033] More specifically, the lubrication system 6 consists of a lubrication reservoir 7 which is formed by a central bore in the inner bearing ring 11. From the reservoir 7 a plurality of grooves 8 forming fluidic connections extend radially into the region of the rolling elements 14.

[0034] Furthermore, it is essential that the lubrication reservoir 7 is sealed against the environment by a valve element 9. The valve element 9 is formed in a shim 10 which is a thin disc which is mounted between one of the side plates 2 and/or 3 and the inner bearing ring 11. The sealing function of the valve element 9 is established by a semi-circular cut in the sheet metal material of which the shim 10 consists. The shim 10 can be produced by an etching process.

[0035] The function of the valve element 9 is described above.

[0036] To sum up, the proposed concept provides a chain saw which includes two side plates forming the guide bar, a shim, a hub (bearing inner ring), a nose sprocket and a plurality of rollers. A tongue (reed valve) is cut at the centre of the shim 10.

[0037] A hole 13 (lubrication bore) is provided on a side plate for the flow of a lubricant. The hub 11 is provided with some channels 8 for guiding the lubricant from the central hole towards the rolling elements 14 around the hub 11.

[0038] The flow of lubricant from the hole 13 via the fluidic connections 8 to the bearing 5 is shown in FIG. 3 by arrows.

[0039] The central hole in the hub works as a lubricant reservoir. The hole for lubrication (lubrication bore) 13 is located outside of the side plate which is closed. This prevents enter of dirt and debris to the rollers.

[0040] The (re-)lubrication can take place by injecting a lubricant via the lubrication bore 13 in one of the side plates 2, 3 as shown in FIGS. 2, 3 and 4.

[0041] It is sufficient that only one shim 10 is provided with the valve element 9. But it is also possible that both shims 10 at both sides of the inner bearing ring 11 are respectively equipped with a valve.

LIST OF REFERENCE NUMERALS

[0042] 1 Guide bar [0043] 2 Side plate [0044] 3 Side plate [0045] 4 Sprocket wheel [0046] 5 Bearing [0047] 6 Lubrication system [0048] 7 Lubrication reservoir [0049] 8 Fluidic connection/Groove [0050] 9 Valve element [0051] 10 Shim [0052] 11 Inner bearing ring/Hub [0053] 12 Screw/Rivet [0054] 13 Lubrication bore [0055] 14 Rolling element