PORTABLE WORKING MACHINE, ESPECIALLY POWER CHAIN SAW

摘要

PROBLEM TO BE SOLVED: To fixedly couple a cylinder to a synthetic substance crank casing perpetually and reduce the configuration height of a cylinder and crank casing unit by reinforcing a mechanical structure with a spherical surface-shaped support plate such as a pressed and punched part integrally buried in the synthetic substance of a lower crank casing. SOLUTION: A support plate 7 is buried in a completely integrated state in the synthetic substance of a lower crank casing 6 to prevent the support plate 7 from becoming slackened and is metallically joined to an upper crank casing 30 within the working range of a fixed socket 19. The head part of a threaded bolt 11 introduces a screw force to a support sleeve through a support sleeve 9 and does not introduce the screw force to the synthetic substance tanklike body of the crank casings 6, 30. The support plate 7 forms the support sleeve 9 to create a metallic thread binding to prevent the lower crank casing 6 from becoming loose or losing its tight seal properties. Thus it is possible to reduce the configuration height of a cylinder and crank casing unit.