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 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 eleme

1. 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 usea 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 placea 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; andsaid second vertical bores being in axial alignment with one another. 2. The apparatus of claim 1, further comprising: a compression tool for engaging said threaded upper end of said compression rod;said compression tool engaging said external threads at the upper end of said compression rod and causing said lower block to travel toward said upper block as said compression tool rotates, said compression rod being unable to rotate about a longitudinal axis of symmetry due to its lower end being fixedly secured to said lower block and said compression rod being forced to travel without rotation along its longitudinal axis of symmetry in response to rotation of said compression tool; andsaid travel of said lower block toward said upper block causing compression of both of said springs. 3. The apparatus of claim 2, further comprising: a longitudinally-extending mounting plate slot formed in said mounting plate and in said cover plate;a displacement pin housing from which said displacement pin extends in normal relation thereto;an elongate control arm having a control aperture formed in a proximal end thereof and having said displacement pin housing secured to a distal end thereof. 4. The apparatus of claim 3, further comprising: a cam pivotally mounted to said mounting plate so that a top edge of said cam abuts a bottom surface of said lower block;said cam having a fully retracted, unpivoted position when said springs are fully compressed and having a fully extended, pivoted position when said springs are fully extended;an angle iron having a first end pivotally mounted to said mounting plate;an angle iron slot formed in a second, lower end of said angle iron;an angle iron square sliding plate having an aperture formed therein;said angle iron positioned between the angle iron square sliding plate and said mounting plate slot;a control pin that extends through said control aperture formed in said proximal end of said control arm, said cover plate slot, said mounting plate slot, said angle iron slot, and through an aperture formed in said angle iron square sliding plate;said angle iron having a fully retracted, unpivoted position when said control pin is positioned at a proximal end of said mounting plate slot when said springs are fully compressed;said angle iron having a fully extended, pivoted position when said control pin is positioned at a distal end of said mounting plate slot when said springs are fully expanded. 5. The apparatus of claim 4, further comprising: said cam having a lobe that abuts said angle iron when said springs are fully compressed, when said springs are fully unloaded, and at all spring compressions therebetween;said control pin having a fully retracted position at a proximal end of said mounting plate slot when said springs are fully compressed;said displacement pin and hence said elongate flat bar having a fully retracted position when said springs are fully compressed;said control pin having a fully extended position at a distal end of said mounting plate slot when said springs are fully expanded;said displacement pin and hence said elongate flat bar having a fully extended position when said springs are fully expanded;said control pin and said displacement pin being displaced in a proximal-to-distal direction by pivotal displacement of said angle iron;said proximal-to-distal displacement of said angle iron caused by pivoting of said cam as said springs expand;said expansion of said springs caused by thermal-related lengthening of said cutting element/chain. 6. The apparatus of claim 5, further comprising: a longitudinally-extending slot formed in said adjustment plate;a pair of apertures formed in said adjustment plate;a pair of apertures formed in said spacer plate;a longitudinally spaced apart pair of adjustment screws that extend through the longitudinally-extending slot formed in said elongate flat bar, through said pair of apertures formed in said spacer plate and through said pair of apertures formed in said adjustment plate;a pair of nuts that respectively screwthreadedly engage said pair of adjustment screws so that when said nuts are tightly secured, said flat elongate bar is held against movement;said nuts having a first fully tightened position that locks said flat elongate bar against movement;said nuts having a second position where the nuts are backed off about half to three-quarters of a turn from said fully tightened position;said flat elongate bar displacing in a proximal-to-distal direction as urged by said bias means as said chainsaw cutting element expands under thermal expansion when said pair of nuts is in said second position. 7. The apparatus of claim 6, further comprising: an anti-rotation plate disposed between said pair of nuts when said pair of nuts is in said second position so that said nuts cannot rotate from said second position. 8. The apparatus of claim 7, further comprising: an anti-rotation pin formed integrally with said spacer plate, said anti-rotation pin having a free end disposed in said elongate slot formed in said elongate flat bar to prevent rotation of said elongate flat bar. 9. The apparatus of claim 8, further comprising: a displacement pin housing guide rod disposed between said mounting plate and said adjustment plate in parallel relation thereto;said displacement pin housing following a path of travel defined by said displacement housing guide rod when said displacement pin housing is displaced in a proximal-to-distal direction by said bias means.