초록 ▼

An apparatus for automatically adjusting a chainsaw cutting element as the chainsaw cutting element lengthens during use due to thermal expansion includes an elongate flat bar circumscribed by the chainsaw cutting element, a motor for causing the chainsaw cutting element to rotate about the elongate

An apparatus for automatically adjusting a chainsaw cutting element as the chainsaw cutting element lengthens during use due to thermal expansion includes an elongate flat bar circumscribed by the chainsaw cutting element, a motor for causing the chainsaw cutting element to rotate about the elongate flat bar, a motor housing for housing the motor and a cover housing secured to the motor housing for covering a proximal end of the elongate flat bar and a rotatably mounted sprocket gear that engages a proximal end of the chainsaw cutting element. The elongate flat bar has a first, fully retracted position, a second, fully extended position, and an infinite number of positions of adjustment therebetween. Bias members continuously urge the elongate flat bar to displace during saw operation in a proximal-to-distal direction from the first, fully retracted position to the second, fully extended position to maintain chain tension at all times.

대표청구항 ▼

1. An apparatus for automatically adjusting an elongate flat bar on a chainsaw circumscribed by a chainsaw cutting element as said chainsaw cutting element lengthens during use, wherein said chainsaw has a motor and said chainsaw cutting element is adapted to rotate about said elongate flat bar, sai

1. An apparatus for automatically adjusting an elongate flat bar on a chainsaw circumscribed by a chainsaw cutting element as said chainsaw cutting element lengthens during use, wherein said chainsaw has a motor and said chainsaw cutting element is adapted to rotate about said elongate flat bar, said apparatus comprising: a motor housing adapted to house said motor;a cover housing secured to said motor housing for covering a proximal end of said elongate flat bar;said elongate flat bar having a first, fully retracted proximal position, a second, fully extended distal position, and an infinite number of positions of adjustment therebetween;a biasing member for urging said elongate flat bar to move in a proximal-to-distal direction as said biasing member displaces from said first, fully retracted position to said second, fully extended position, said proximal-to-distal displacement being movement away from said motor housing in a plane of said elongate flat bar;said biasing member including an elongate screw;said biasing member further including a proximal block fixedly secured to said cover housing and having an unthreaded bore formed therein;said biasing member further including a distal block fixedly secured to said cover housing in longitudinally spaced apart relation to said proximal block and having an unthreaded bore formed therein;said elongate screw having a proximal end that slideably extend through said unthreaded bore formed in said proximal block;said elongate screw having a distal end that slidably extends through said unthreaded bore formed in said distal block;said biasing member further including a flat base plate having an unthreaded bore formed therein to receive said elongate screw, said flat base plate being welded to said elongate screw;said flat base plate positioned between said proximal block and said distal block;said biasing member further including an elongate spring, said elongate spring having a distal end that abuts said distal block and having a proximal end that abuts said flat, internally threaded base plate;said flat, unthreaded base plate abutting said proximal block when said elongate spring is fully extended; andsaid flat base plate being spaced away from said proximal block when said elongate spring is compressed, said flat base plate being spaced a maximum distance from said proximal block when said elongate spring is fully compressed. 2. The apparatus of claim 1, further comprising: said base plate having a surface that abuts said cover housing and slides but does not rotate relative to said cover housing;a compression tool that rotatably engages the distal end of said elongate screw;said elongate spring being compressed as said base plate is drawn in a proximal-to-distal direction by rotation of said compression tool that engages said distal end of said screw when said compression tool abuts said distal block;said elongate screw and said base plate traveling in a distal-to-proximal direction without rotation as said elongate spring extends. 3. The apparatus of claim 2, further comprising: a pivotally mounted ratchet base plate having an unrotated position or repose when said elongate spring is fully compressed;said ratchet base plate having a fully rotated position when said elongate spring is fully extended;said ratchet base plate being positioned on a proximal side of said proximal block in longitudinal alignment with said elongate screw so that distal-to-proximal travel of said elongate screw effect pivotal rotation of said ratchet base plate away from said position of repose. 4. The apparatus of claim 3, further comprising: a ratchet main body plate is fixedly secured to and depends from said ratchet base plate;a plurality of teeth formed in a proximal edge of said ratchet main body plate;a pawl positioned adjacent said ratchet main body plate;said pawl sequentially engaging said teeth, beginning at a first end of said ratchet main body plate, as said ratchet base plate is pivotally displaced by said elongate screw as said elongate spring extends; andsaid plurality of teeth being sloped so that said pawl allows the pivoting of said ratchet main body plate in a first direction and such that said pawl does interfere with and prevent pivoting of said ratchet main body plate in a second direction opposite to said first direction. 5. The apparatus of claim 4, further comprising: said pawl being provided with handles that allow said pawl to be pulled out of engagement with said teeth by overcoming the bias of a spring that loads said pawl;said pawl being pulled out of engagement with said teeth when a new chain is being installed;said ratchet base plate being rotated from its fully rotated position to its initial, unrotated position of repose when said pawl is pulled out of engagement with said teeth. 6. The apparatus of claim 5, further comprising: an elongate control arm for interconnecting said ratchet main body plate and said elongate flat bar;a control slot formed in the proximal end of said elongate control arm;a distal edge of said ratchet main body plate being disposed within said control slot so that the teeth formed in the proximal edge of said ratchet main body plate are in open communication with said pawl;a displacement aperture formed in a proximal end of said elongate flat bar;said elongate control arm having a ninety degree (90°) bend formed in a distal end of said elongate control arm;a displacement pin extending from said distal end so that said displacement pin can engage said displacement aperture;said ratchet main body plate being displaced by pivoting of said ratchet base plate in first direction, which pivoting is caused by expansion of said elongate spring as said ratchet base plate is pivotally displaced by the bias of said elongate spring;said displacement of aid ratchet base plate being simultaneously transmitted to said elongate flat bar by said elongate control bar and said displacement pin as said cutting element lengthens under thermal expansion, which allows expansion of said elongate spring, said spring expansion resulting in proximal-to-distal travel of said elongate control rod.