Cutting – Cutter assemblage or cutter element therefor – Having noncutting depth gauge
Patent
1983-11-29
1986-06-10
Meister, James M.
Cutting
Cutter assemblage or cutter element therefor
Having noncutting depth gauge
83833, B27B 3314, B27B 1702
Patent
active
045935912
DESCRIPTION:
BRIEF SUMMARY
This invention relates to chain saw bars and to a chain for use in combination with such a bar.
The invention is particularly directed to a chain saw bar of the type having a sprocket or a roller rotatably supported at the forward end of the bar, to guide the chain as it travels from the top to the bottom edge of the bar. Chain saw bars of these constructions are commonly referred to as "sprocket nose bars" and "roller nose bars" respectively.
Throughout this specification the reference to a "chain saw chain" means a chain comprising a plurality of alternate cutter links and connector links with drive links connecting each cutter link to the respective adjacent connector links. Each drive link is a single member located centrally of the width of the chain, and has a dependent tongue to be received between successive teeth of a driving sprocket. The cutting links each comprise a body portion with transverse apertures for pivotally connecting the cutter link to the respective adjoining drive links, and a transverse land integral with the body portion having a cutting edge at the forward end and a heel at the rearward end. A depth gauge projection is provided forward of the cutting edge.
One of the major problems associated with the use of a chain saw is the tendency of the saw to kick back towards the operator, when the section of the chain passing around the nose of the bar is being used to cut material. In these circumstances, the reaction force to the cutting action of the chain tends to throw the nose end of the bar upwardly and backwardly towards the operator. Hence the saw tends to pivot in this direction in the hands of the operator, and may come into contact with the body of the operator, and cause serious injury thereto.
The degree of severity of kick back is relative to the depth of cut being made by that portion of the chain travelling around the nose of the bar. In a conventional chain, the depth of cut is controlled by the depth gauge protection on the cutter link in advance of the cutting edge. If the depth gauge projection was set so that a relatively small cut is made by each cutter link, the severity of kick back would be reduced. However, this would also result in a reduction of the cutting rate of the chain when being used on the straight portion of the cutter bar and is therefore undesirable.
In addition, the depth gauge projection on a conventional chain, can induce a degree of kick back, for as the chain passes around the curved nose portion of the bar, the depth gauge projection take up an attitude to the surface of the cut, which will allow the depth gauge projection to dig into the material in a manner similar to the cutting edge. This digging in of the depth gauge projection produces the same type of reaction as the cutting edge of the cutter link, and so also contributes to the risk of kick back. Further as the cutter link undergoes changes in angular attitude to the cut surface of the material, as it passes around the nose portion of the bar, the cutting edge of the cutter link may take a deeper cut than is possible when the chain is moving along the straight portion of the bar.
Thus, at present, it is necessary to make a compromise between the acceptable rate of cutting when operating on the straight portion of the bar, and the degree of safety required when cutting with the nose portion of the bar.
Skilled operators of chain saws are aware of the tendency for the saw to kick back, and accordingly take precautions to guard against possible injury, when using the nose portion of the bar for cutting. However, there are other occasions when the nose portion of the chain may accidentally come in contact with an object that offers resistance to the cutting action of the cutter link and therefore kick back may occur when the operator is not prepared. Also it will be appreciated that risk of kick back and resultant serious injury are always present when a chain saw is being used by an unskilled operator.
It is the object of the present invention to provide a chain saw bar, and a chain s
REFERENCES:
patent: 2771919 (1956-11-01), Cox
patent: 4408393 (1983-10-01), Jerabek
patent: 4484504 (1984-11-01), Atkinson
LandOfFree
Chain saws and chains therefor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Chain saws and chains therefor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Chain saws and chains therefor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2402445