An apparatus for automatically adjusting a chainsaw cutting element as said chainsaw cutting element lengthens during use due to thermal expansion, comprising:
- an elongate flat bar circumscribed by said chainsaw cutting element;
- a motor housing adapted to house a motor, said chainsaw cutting element adapted to rotate about said elongate flat bar by said motor;
- a cover plate secured to said motor housing for covering a proximal end of said elongate flat bar;
- said elongate flat bar having a first, fully retracted position, a second, fully extended position, and an infinite number of positions of adjustment therebetween;
- a bias means for urging said elongate flat bar to move in a proximal-to-distal direction as it 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 bias means thereby automatically moving said elongate flat bar a distance in the proximal-to-distal direction as said chainsaw cutting element lengthens from thermal expansion;
- a longitudinally-extending slot formed in a proximal end of said elongate flat bar;
- an adjustment plate secured to said cover plate in parallel relation to a proximal end of said elongate flat bar, said adjustment plate having a fixed position with respect to said motor housing and said cover plate;
- a flat spacer plate disposed between said adjustment plate and said elongate flat bar, said flat spacer plate secured in a fixed position to said adjustment plate;
- a spacer plate pin secured to said flat spacer plate in normal relation thereto, said spacer plate pin extending into said longitudinally-extending slot formed in said flat elongate bar;
- said spacer plate pin disposed in a distal end of said longitudinally-extending slot when said elongate flat bar is in its fully retracted position;
- said elongate flat bar being in said fully retracted position when said chainsaw cutting element is new and has not undergone thermal expansion;
- said spacer plate pin disposed in a proximal end of said longitudinally-extending slot when said elongate flat bar is in its fully extended position;
- said elongate flat bar being in said fully extended position when said chainsaw cutting element is fully thermally expanded due to extensive use
- a first aperture formed in said elongate flat bar;
- a displacement pin disposed normal to the plane of said elongate flat bar, said displacement pin extending into said first aperture;
- said displacement pin being biased by said bias means to travel in a proximal-to-distal direction so that as said chainsaw cutting element undergoes thermal expansion during use, said displacement pin travels in a proximal-to-distal direction and carries said elongate flat bar in said proximal-to-distal direction as said thermal expansion takes place
- a mounting plate secured to said cover plate in overlying relation thereto;
- an upper block fixedly secured to an upper end of said mounting plate;
- a lower block positioned below said upper block but not connected to said mounting plate;
- a pair of high tension springs disposed between said upper block and said lower block;
- a spring guide rod ensleeved by a first spring of said pair of springs;
- a compression rod ensleeved by a second spring of said pair of springs;
- said spring guide rod having an upper end received within and secured to a first vertical bore formed in said upper block so that said spring guide rod cannot rotate about its longitudinal axis;
- said spring guide rod having a lower end slideably received within a first vertical bore formed in said lower block;
- said first vertical bores being in axial alignment with one another;
- said compression rod having an externally threaded upper end extending through and slideably received within a second vertical bore formed in said upper block;
- said compression rod having a lower end received within and secured to a second vertical bore formed in said lower block so that said compression rod cannot rotate about its longitudinal axis;
- and
- said second vertical bores being in axial alignment with one another.