Michael J Lay

US Patent:

39676986, Jul 6, 1976

Filed:

Mar 20, 1975

Appl. No.:

5/560535

Inventors:

Richard Thomas Smith - Columbia MO
Michael T. Lay - Columbia MO

Assignee:

McGraw-Edison Company - Elgin IL

International Classification:

F16N 7 14

US Classification:

184 15A

Abstract:

A power chain saw oiling device that automatically supplies lubricating oil to the cutting chain and guiding cutting bar. The device is easy and economical to fabricate and to assemble in the saw. An oil reservoir is formed in the saw housing and an oil flow path leads from the reservoir through a piston type pump to an oil distribution cavity open to the cutting bar and chain. The piston is operated directly by sliding contact against a cam rotated with the output shaft. A bypass tube of relatively narrow cross section is provided from the pump output chamber and discharges into the oil reservoir from its discharge end which is located above the distribution cavity to the cutting bar and chain. Oil flow from the pump is thus directed both to the oil distribution cavity for chain lubrication and to the bypass tube back to the oil reservoir. Under normal saw operation oil flow occurs to both, with sufficient discharge occurring to the chain for proper lubrication thereof; whereas the uphill pitch of the bypass tube creates a back pressure so that under low speed saw operation most, if not all, of the oil flow effectively goes to lubricate the chain and little or no oil is bypassed to the oil reservoir.