Apparatus for reducing the operating noise of a chain saw

Claim 2

In a chain saw including an apparatus for reducing the noise generated by an operating chain saw wherein said chain includes: chain saw cutting means including guide bar means, cutter chain means supported on said guide bar means, chain saw engine means including piston and cylinder means, and crankshaft means driven by said piston means of said piston and cylinder means, and operable to transmit driving force to said cutter chain means; said apparatus comprising: conduit means operable to transmit exhaust fluid from said cylinder means of said piston and cylinder means, surge chamber means, said surge chamber means being operable to receive exhaust fluid from said conduit means, said surge chamber means being supported on the exterior of said cylinder means, acoustic filter means including first, generally perforate, outlet passage defining means, a generally longitudinal axis of said first outlet passage defining means being transversely desplaced from a generally longitudinal axis of of said conduit means, with said conduit means and said first outlet passage defining means being mutually, transversely offset, second, generally perforate, outlet passage defining means contained within said first outlet passage defining means and at least partially spaced therefrom. first end portions of each of said first and second outlet passage defining means housed within the interior of said surge chamber means, barrier means closing said first end portions of said first and second outlet passage defining means, perforate wall means extending generally transversely of and between second end portions of said first and second outlet passage defining means, outlet means provided by a second end of said second outlet passage defining means, said outlet means and said perforate wall means being operable to transmit exhaust fluid to the exterior of said surge chamber means, said first outlet passage defining means including a plurality of first perforation means, said second outlet passage defining means including a plurality of second perforation means, with said second perforation means being operable to arrest the passage of sparks, each said first perforation means of said first outlet passage defining means generally encircling, and exposing to the interior of said surge chamber means, a plurality of second perforation means of said second outlet passage defining means, constricted flow path means interposed generally between said first and second outlet passage defining means; deflector means operable to deflect exhaust fluid exiting from said outlet means of said second outlet passage defining means.

Claim 3

An apparatus as described in claim 1 wherein said deflector means comprises: arcuate wall means comprising a generally quarter sphere configuration; means rotatably supporting said arcuate wall means for rotation about a longitudinal axis of said second, outlet passage defining means; and locking means for selectively securing said arcuate wall means in a selected position of rotation.

Claim 4

In a chain saw including an apparatus for reducing the noise generated by an operating chain saw wherein said chain includes: chain saw cutting means including guide bar means, cutter chain means supported on said guide bar means for movement through a cutting plane, with said cutting plane being aligned in generally parallel relation with a principal vibRation plane of a chain saw; chain saw engine means including piston and cylinder means, and crankshaft means driven by said piston means of said piston and cylinder means, and operable to transmit driving force to said cutter chain means, said crankshaft means being mounted for rotation about an axis of crankshaft rotation extending generally perpendicular to said principal vibration plane; said apparatus comprising: conduit means operable to transmit exhaust fluid from said cylinder means of said piston and cylinder means, said conduit means having a generally rectangularly elongate cross section, and said conduit means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation; surge chamber means, said surge chamber means being operable to receive exhaust fluid from said conduit means, said surge chamber means being supported on the exterior of said cylinder means, said conduit means extending from said surge chamber means and being directly connected with the exterior of said cylinder means and disposed in direct, metal-to-metal engagement therewith, said surge chamber means having a generally rectangular configuration including a generally rectangular cross section extending generally parallel with said principal vibration plane; acoustic filter means including first, generally perforate cylinder means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation, a longitudinal, generally central axis of said first cylinder means being transversely displaced from a longitudinal, generally central axis of said conduit means, with said conduit means and said first cylinder means being mutually, transversely offset, second, generally perforate cylinder means contained within said first cylinder means and at least partially spaced therefrom. first end portions of each of said first and second cylinder means which are generally mutually contiguous and housed within the interior of said surge chamber means, barrier means closing said first end portions of said first and second cylinder means, perforate wall means extending generally transversely of and between second end portions of said first and second cylinder means, outlet means provided by a second end of said second cylinder means, said outlet means and said perforate wall means being operable to transmit exhaust fluid to the exterior of said surge chamber means, said first cylinder means including a plurality of generally radially opening and circumferentially spaced first perforation means, said second cylinder means including a plurality of generally radially opening and circumferentially spaced second perforation means, with said second perforation means being operable to arrest the passage of sparks, each said first perforation means of said first cylinder means generally encircling, and exposing to the interior of said surge chamber means, a plurality of second perforation means of said second cylinder means, constricted, annular flow path means interposed generally radially between first and second cylinder means and including a generally imperforate portion of said first cylinder means located generally adjacent said perforate wall means, said constricted, annular flow path means extending along an axis which is generally perpendicular to said principal vibration plane, said cutter chain means and chain saw engine means being operable to generate vibrations generally aligned with said principal vibration plane and acting on said first and second cylinder means to generate vibrations therein directed generally transversely of said constricted annular flow path and in general alignment with said principal vibration plane; a plurality of tubular baffle means, said tubular baffle means being located within the interior of said surge chamber means, each said tubular baffle means extending generAlly parallel to said axis of crankshaft rotation, and said tubular baffle means being mutually displaced and spaced generally radially outwardly of said first cylinder means; said conduit means, said first and second cylinder means, said constricted annular flow path and said tubular baffle means being generally mutually parallel and subject to said vibrations generated in general alignment with said principal vibration plane; and arcuate deflector means operable to deflect exhaust fluid exiting from said outlet means of said second cylinder means generally transversely of said axis of crankshaft rotation, said arcuate deflector means including, arcuate wall means comprising a generally quarter sphere configuration, said generally quarter sphere configuration having a center of curvature generally coincident with a generally central longitudinal axis of said second cylinder means.

Claim 5

In a chain saw including an apparatus for reducing the noise generated by an operating chain saw wherein said chain includes: chain saw cutting means including guide bar means, cutter chain means supported on said guide bar means for movement through a cutting plane, with said cutting plane being aligned in generally parallel relation with a principal vibRation plane of a chain saw; chain saw engine means including piston and cylinder means, and crankshaft means driven by said piston means of said piston and cylinder means, and operable to transmit driving force to said cutter chain means, said crankshaft means being mounted for rotation about an axis of crankshaft rotation extending generally perpendicular to said principal vibration plane; said apparatus comprising: conduit means operable to transmit exhaust fluid from said cylinder means of said piston and cylinder means, said conduit means having a generally rectangularly elongate cross section, and said conduit means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation; surge chamber means, said surge chamber means being operable to receive exhaust fluid from said conduit means, said surge chamber means being supported on the exterior of said cylinder means, said conduit means extending from said surge chamber means and being directly connected with the exterior of said cylinder means and disposed in direct, metal-to-metal engagement therewith, said surge chamber means having a generally rectangular configuration including a generally rectangular cross section extending generally parallel with said principal vibration plane; acoustic filter means including first, generally perforate cylinder means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation, a longitudinal, generally central axis of said first cylinder means being transversely displaced from a longitudinal, generally central axis of said conduit means, with said conduit means and said first cylinder means being mutually, transversely offset, second, generally perforate cylinder means contained within said first cylinder means and at least partially spaced therefrom. first end portions of each of said first and second cylinder means which are generally mutually contiguous and housed within the interior of said surge chamber means, barrier means closing said first end portions of said first and second cylinder means, perforate wall means extending generally transversely of and between second end portions of said first and second cylinder means, outlet means provided by a second end of said second cylinder means, said outlet means and said perforate wall means being operable to transmit exhaust fluid to the exterior of said surge chamber means, said first cylinder means including a plurality of generally radially opening and circumferentially spaced first perforation means, said second cylinder means including a plurality of generally radially opening and circumferentially spaced second perforation means, with said second perforation means being operable to arrest the passage of sparks, each said first perforation means of said first cylinder means generally encircling, and exposing to the interior of said surge chamber means, a plurality of second perforation means of said second cylinder means, constricted, annular flow path means interposed generally radially between first and second cylinder means and including a generally imperforate portion of said first cylinder means located generally adjacent said perforate wall means, said constricted, annular flow path means extending along an axis which is generally perpendicular to said principal vibration plane, said cutter chain means and chain saw engine means being operable to generate vibrations generally aligned with said principal vibration plane and acting on said first and second cylinder means to generate vibrations therein directed generally transversely of said constricted annular flow path and in general alignment with said principal vibration plane; a plurality of tubular baffle means, said tubular baffle means being located within the interior of said surge chamber means, each said tubular baffle means extending generAlly parallel to said axis of crankshaft rotation, and said tubular baffle means being mutually displaced and spaced generally radially outwardly of said first cylinder means; said conduit means, said first and second cylinder means, said constricted annular flow path and said tubular baffle means being generally mutually parallel and subject to said vibrations generated in general alignment with said principal vibration plane; and arcuate deflector means operable to deflect exhaust fluid exiting from said outlet means of said second cylinder means generally transversely of said axis of crankshaft rotation, said arcuate deflector means including, arcuate wall means comprising a generally quarter sphere configuration, said generally quarter sphere configuration having a center of curvature generally coincident with a generally central longitudinal axis of said second cylinder means.

Claim 6

In a chain saw including an apparatus for reducing the noise generated by an operating chain saw wherein said chain saw includes: chain saw cutting means including guide bar means, cutter chain means supported on said guide bar means for movement through a cutting plane with said cutting plane being aligned in generally parallel relation with a principal vibration plane of a chain saw; chain saw engine means including piston and cylinder means, crankshaft means driven by said piston means of said piston and cylinder means, and operable to transmit driving force to said cutter chain means, and said crankshaft means being mounted for rotation about an axis of crankshaft rotation extending generally perpendicular to said principal vibration plane; said apparatus comprising: conduit means operable to transmit exhaust fluid from said cylinder means of said piston and cylinder means, said conduit means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation; surge chamber means, said surge chamber means being operable to receive exhaust fluid from said conduit means, said surge chamber means being supported on the exterior of said cylinder means, said surge chamber means having a generally rectangular cross section extending parallel with said principal vibration plane; acoustic filter means including generally perforate cylinder means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation, a longitudinal, generally central axis of said cylinder means being transversely displaced from a longitudinal, generally central axis of said conduit means, with said conduit means and said cylinder means being mutually, transversly offset, barrier means within said surge chamber means closing a first end portion of said cylinder means, outlet means provided by a second end of said passage cylinder means, said outlet means being operable to transmit exhaust fluid to the exterior of said surge chamber means, said cylinder means including a plurality of generally radially opening and circumferentially spaced perforation means, and said cutter chain means and chain saw engine means being operable to generate vibrations generally aligned with said principal vibration plane and acting on said cylinder means to generate vibrations therein directed generally transversely thereof and in general alignment with said principal vibration plane, cantilever beam means extending generally transversely across said outlet means of said outlet passage defining means and including flexible reed means, and cantilever support, anchor means fixedly securing one end of said reed means to the exterior of said surge chamber means, with another end of said reed means extending at least partially across said outlet means and movable generally outwardly thereof.

Claim 7

In a chain saw including an apparatus for reducing the noise generated by an operating chain saw wherein said chain saw includes: chain saw cutting means including guide bar means, cutter chain means supported on said guide bar means for movement through a cutting plane with said cutting plane being aligned in generally parallel relation with a principal vibration plane of a chain saw; chain saw engine means including piston and cylinder means, crankshaft means driven by said piston means of said piston and cylinder means, and operable to transmit driving force to said cutter chain means, and said crankshaft means being mounted for rotation about an axis of crankshaft rotation extending generally perpendicular to said principal vibration plane; said apparatus comprising: conduit means operable to transmit exhaust fluid from said cylinder means of said piston and cylinder means, said conduit means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation; surge chamber means, said surge chamber means being operable to receive exhaust fluid from said conduit means, said surge chamber means being supported on the exterior of said cylinder means, said surge chamber means having a generally rectangular cross section extending parallel with said principal vibration plane; acoustic filter means including generally perforate cylinder means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation, a longitudinal, generally central axis of said cylinder means being transversely displaced from a longitudinal, generally central axis of said conduit means, with said conduit means and said cylinder means being mutually, transversly offset, barrier means within said surge chamber means closing a first end portion of said cylinder means, outlet means provided by a second end of said passage cylinder means, said outlet means being operable to transmit exhaust fluid to the exterior of said surge chamber means, said cylinder means including a plurality of generally radially opening and circumferentially spaced perforation means, and said cutter chain means and chain saw engine means being operable to generate vibrations generally aligned with said principal vibration plane and acting on said cylinder means to generate vibrations therein directed generally transversely thereof and in general alignment with said principal vibration plane, cantilever beam means extending generally transversely across said outlet means of said outlet passage defining means and including flexible reed means, and cantilever support, anchor means fixedly securing one end of said reed means to the exterior of said surge chamber means, with another end of said reed means extending at least partially across said outlet means and movable generally outwardly thereof.

Claim 8

In a chain saw including an apparatus for reducing the noise generated by an operating chain saw wherein said chain saw includes: chain saw cutting means including guide bar means, cutter chain means supported on said guide bar means for movement through a cutting plane, with said cutting plane being aligned in generally parallel relation with a principal vibration plane of a chain saw; chain saw engine means including piston and cylinder means, and crankshaft means driven by said piston means of said piston and cylinder means, and operable to transmit driving force to said cutter chain means, said crankshaft means being mounted for rotation about an axis of crankshaft rotation extending generally perpendicular to said principal vibration plane; said apparatus comprising: conduit means operable to transmit exhaust fluid from said cylinder means of said piston and cylinder means, said conduit means having a generally rectangularly elongate cross section, and said conduit means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation; surge chamber means, said surge chamber means being operable to receive exhaust fluid from said conduit means, said surge chamber means being supported on the exterior of said cylinder means, said conduit means extending from said surge chamber means and being directly connected with the exterior of said cylinder means and disposed in direct, metal-to-metal engagement therewith, said surge chamber means having a generally rectangular configuration including a generally rectangular cross section extending generally parallel with said principal vibration plane; acoustic filter means including generally perforate cylinder means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation, a longitudinal, generally central axis of said cylinder means being transversely displaced from a longitudinal, generally central axis of said conduit means, with said conduit means and said cylinder means being mutually, transversely offset, barrier means within said surge chamber means closing a first end portion of said cylinder means, outlet means provided by a second end of said cylinder means, said outlet means being operable to transmit exhaust fluid to the exterior of said chamber means, said cylinder means including a plurality of generally radially opening and circumferentially spaced perforation means, said cutter chain means and chain saw engine means being operable to generate vibrations generally aligned with said principal vibration plane and acting on said cylinder means to generate vibrations therein directed generally transversely thereof and in general alignment with said principal vibration plane; a plurality of tubular baffle means, said tubular baffle means being located within the interior of said surge chamber means, each said tubular baffle means extending generally parallel to said axis of crankshaft rotation, and said tubular baffle means being mutually displaced and spaced generally radially outwardly of said cylinder means; said conduit means, said cylinder means and said tubular baffle means being generally mutually parallel and subject to said vibrations generated in general alignment with said principal vibration plane; and cantilever beam means extending generally transversely across said outlet means of said cylinder means and including generally flat, flexible reed means extending generally parallel with said principal vibration plane, cantilever support, anchor means fixedly securing one end of said generally flat reed means to the exterior of said surge chamber means, with another end of said generally flat reed means extending at least partially across said outlet means and movable generally outwardly thereof, and flexible stiffener means overlapping and generally contiguous with said generally flat reed means and operable to permit, but resiliently impede, flexing of said generally flat reed means in response to the pressure of exhaust fluid passing through said outlEt means; and continuously open vent means permitting a continuous passage of exhaust fluid through said outlet means independent of the position of said other end of said generally flat reed means relative to said outlet means.

Claim 9

In a chain saw including an apparatus for reducing the noise generated by an operating chain saw wherein said chain saw includes: chain saw cutting means including guide bar means, cutter chain means supported on said guide bar means for movement through a cutting plane, with said cutting plane being aligned in generally parallel relation with a principal vibration plane of a chain saw; chain saw engine means including piston and cylinder means, and crankshaft means driven by said piston means of said piston and cylinder means, and operable to transmit driving force to said cutter chain means, said crankshaft means being mounted for rotation about an axis of crankshaft rotation extending generally perpendicular to said principal vibration plane; said apparatus comprising: conduit means operable to transmit exhaust fluid from said cylinder means of said piston and cylinder means, said conduit means having a generally rectangularly elongate cross section, and said conduit means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation; surge chamber means, said surge chamber means being operable to receive exhaust fluid from said conduit means, said surge chamber means being supported on the exterior of said cylinder means, said conduit means extending from said surge chamber means and being directly connected with the exterior of said cylinder means and disposed in direct, metal-to-metal engagement therewith, said surge chamber means having a generally rectangular configuration including a generally rectangular cross section extending generally parallel with said principal vibration plane; acoustic filter means including generally perforate cylinder means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation, a longitudinal, generally central axis of said cylinder means being transversely displaced from a longitudinal, generally central axis of said conduit means, with said conduit means and said cylinder means being mutually, transversely offset, barrier means within said surge chamber means closing a first end portion of said cylinder means, outlet means provided by a second end of said cylinder means, said outlet means being operable to transmit exhaust fluid to the exterior of said chamber means, said cylinder means including a plurality of generally radially opening and circumferentially spaced perforation means, said cutter chain means and chain saw engine means being operable to generate vibrations generally aligned with said principal vibration plane and acting on said cylinder means to generate vibrations therein directed generally transversely thereof and in general alignment with said principal vibration plane; a plurality of tubular baffle means, said tubular baffle means being located within the interior of said surge chamber means, each said tubular baffle means extending generally parallel to said axis of crankshaft rotation, and said tubular baffle means being mutually displaced and spaced generally radially outwardly of said cylinder means; said conduit means, said cylinder means and said tubular baffle means being generally mutually parallel and subject to said vibrations generated in general alignment with said principal vibration plane; and cantilever beam means extending generally transversely across said outlet means of said cylinder means and including generally flat, flexible reed means extending generally parallel with said principal vibration plane, cantilever support, anchor means fixedly securing one end of said generally flat reed means to the exterior of said surge chamber means, with another end of said generally flat reed means extending at least partially across said outlet means and movable generally outwardly thereof, and flexible stiffener means overlapping and generally contiguous with said generally flat reed means and operable to permit, but resiliently impede, flexing of said generally flat reed means in response to the pressure of exhaust fluid passing through said outlEt means; and continuously open vent means permitting a continuous passage of exhaust fluid through said outlet means independent of the position of said other end of said generally flat reed means relative to said outlet means.

Claim 10

In a chain saw including an apparatus for reducing the noise generated by an operating chain saw, wherein said chain saw includes: chain saw cutting means including guide bar means, cutter chain means supported on said guide bar means for movement through a cutting plane with said cutting plane being aligned in generally parallel relation with a principal vibration plane of a chain saw; chain saw engine means including piston and cylinder means, crankshaft means driven by said piston means of said piston and cylinder means, and operable to transmit driving force to said cutter chain means; and said crankshaft means being mounted for rotation about an axis of crankshaft rotation extending generally perpendicular to said principal vibration plane; said apparatus comprising conduit means operable to transmit exhaust fluid from said cylinder means of said piston and cylinder means; said conduit means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation; surge chamber means, said surge chamber means being operable to receive exhaust fluid from said conduit means; said surge chamber means having a generally rectangular cross section extending generally parallel with said principal vibration plane; acoustic filter means including generally perforate cylinder means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation, a longitudinal, generally central axis of said cylinder means being transversely displaced from a longitudinal, generally central axis of said conduit means, with said conduit means and said cylinder means being mutually, transversely offset, barrier means within said surge chamber means closing a first end portion of said cylinder means, outlet means provided by a second end of said cylinder means, said outlet means being operable to transmit exhaust fluid to the exterior of said surge chamber means, said cylinder means including a plurality of generally radially opening and circumferentially spaced perforation means, and said cutter chain means and chain saw engine means being operable to generate vibrations generally aligned with said principal vibration plane and acting on said cylinder means to generate vibrations therein directed generally transversely thereof and in general alignment with said principal vibration plane.

Claim 11

In a chain saw including an apparatus for reducing the noise generated by an operating chain saw, wherein said chain saw includes: chain saw cutting means including guide bar means, cutter chain means supported on said guide bar means for movement through a cutting plane with said cutting plane being aligned in generally parallel relation with a principal vibration plane of a chain saw; chain saw engine means including piston and cylinder means, crankshaft means driven by said piston means of said piston and cylinder means, and operable to transmit driving force to said cutter chain means; and said crankshaft means being mounted for rotation about an axis of crankshaft rotation extending generally perpendicular to said principal vibration plane; said apparatus comprising conduit means operable to transmit exhaust fluid from said cylinder means of said piston and cylinder means; said conduit means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation; surge chamber means, said surge chamber means being operable to receive exhaust fluid from said conduit means; said surge chamber means having a generally rectangular cross section extending generally parallel with said principal vibration plane; acoustic filter means including generally perforate cylinder means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation, a longitudinal, generally central axis of said cylinder means being transversely displaced from a longitudinal, generally central axis of said conduit means, with said conduit means and said cylinder means being mutually, transversely offset, barrier means within said surge chamber means closing a first end portion of said cylinder means, outlet means provided by a second end of said cylinder means, said outlet means being operable to transmit exhaust fluid to the exterior of said surge chamber means, said cylinder means including a plurality of generally radially opening and circumferentially spaced perforation means, and said cutter chain means and chain saw engine means being operable to generate vibrations generally aligned with said principal vibration plane and acting on said cylinder means to generate vibrations therein directed generally transversely thereof and in general alignment with said principal vibration plane.

Claim 12

In a chain saw including an apparatus for reducing the noise generated by an operating chain saw, wherein said chain saw includes: chain saw cutting means including guide bar means, cutter chain means supported on said guide bar means for movement through a cutting plane, with said cutting plane being aligned in generally parallel relation with a principal vibration plane of a chain saw; chain saw engine means including piston and cylinder means, crankshaft means driven by said piston means of said piston and cylinder means, and operable to transmit driving force to said cutter chain means, said crankshaft means being mounted for rotation about an axis of crankshaft rotation extending generally perpendicular to said principal vibration plane; said apparatus comprising: conduit means operable to transmit exhaust fluid from said cylinder means of said piston and cylinder means, said conduit means having a generally rectangularly elongate cross section, and said conduit means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation; surge chamber means, said surge chamber means being operable to receive exhaust fluid from said conduit means, said surge chamber means being supported on the exterior of said cylinder means, said conduiT means extending from said surge chamber means and being directly connected with the exterior of said cylinder means and disposed in direct, metal-to-metal engagement therewith, said surge chamber means having a generally rectangular configuration including a generally rectangular cross section extending generally parallel with said principal vibration plane; acoustic filter means including generally perforate cylinder means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation, a longitudinal, generally central axis of said cylinder means being transversely displaced from a longitudinal, generally central axis of said conduit means, with said conduit means and said cylinder means being mutually, transversely offset, barrier means within said surge chamber means closing a first end portion of said cylinder means, outlet means provided by a second end of said second cylinder means, said outlet means being operable to transmit exhaust fluid to the exterior of said surge chamber means, said cylinder means including a plurality of generally radially opening and circumferentially spaced perforation means, and said cutter chain means and chain saw engine means being operable to generate vibrations generally aligned with said principal vibration plane and acting on said cylinder means to generate vibrations therein directed generally transversely thereof and in general alignment with said principal vibration plane; and a plurality of tubular baffle means, said tubular baffle means being located within the interior of said surge chamber means, each said tubular baffle means extending generally parallel to said axis of crankshaft rotation, and said tubular baffle means mutually displaced and spaced generally radially outwardly of said cylinder means; said conduit means, said cylinder means, and said tubular baffle means being generally mutually parallel and subject to said vibrations generated in general alignment with said principal vibration plane.

Claim 13

In a chain saw including an apparatus for reducing the noise generated by an operating chain saw, wherein said chain saw includes: chain saw cutting means including guide bar means, cutter chain means supported on said guide bar means for movement through a cutting plane, with said cutting plane being aligned in generally parallel relation with a principal vibration plane of a chain saw; chain saw engine means including piston and cylinder means, crankshaft means driven by said piston means of said piston and cylinder means, and operable to transmit driving force to said cutter chain means, said crankshaft means being mounted for rotation about an axis of crankshaft rotation extending generally perpendicular to said principal vibration plane; said apparatus comprising: conduit means operable to transmit exhaust fluid from said cylinder means of said piston and cylinder means, said conduit means having a generally rectangularly elongate cross section, and said conduit means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation; surge chamber means, said surge chamber means being operable to receive exhaust fluid from said conduit means, said surge chamber means being supported on the exterior of said cylinder means, said conduiT means extending from said surge chamber means and being directly connected with the exterior of said cylinder means and disposed in direct, metal-to-metal engagement therewith, said surge chamber means having a generally rectangular configuration including a generally rectangular cross section extending generally parallel with said principal vibration plane; acoustic filter means including generally perforate cylinder means having a longitudinal axis extending generally parallel to said axis of crankshaft rotation, a longitudinal, generally central axis of said cylinder means being transversely displaced from a longitudinal, generally central axis of said conduit means, with said conduit means and said cylinder means being mutually, transversely offset, barrier means within said surge chamber means closing a first end portion of said cylinder means, outlet means provided by a second end of said second cylinder means, said outlet means being operable to transmit exhaust fluid to the exterior of said surge chamber means, said cylinder means including a plurality of generally radially opening and circumferentially spaced perforation means, and said cutter chain means and chain saw engine means being operable to generate vibrations generally aligned with said principal vibration plane and acting on said cylinder means to generate vibrations therein directed generally transversely thereof and in general alignment with said principal vibration plane; and a plurality of tubular baffle means, said tubular baffle means being located within the interior of said surge chamber means, each said tubular baffle means extending generally parallel to said axis of crankshaft rotation, and said tubular baffle means mutually displaced and spaced generally radially outwardly of said cylinder means; said conduit means, said cylinder means, and said tubular baffle means being generally mutually parallel and subject to said vibrations generated in general alignment with said principal vibration plane.