Air pulse noise damper for a pneumatic tool

Claim 2

A pneumatic tool including an air driven motor comprising a rotor liner defining a rotor chamber having an air driven multiple vane rotor operable therein and having at least one exhaust port through the periphery of the liner for exhaust of driving air from the rotor chamber; a housing for the tool encasing the motor; and a sound attenuating system through which the exhaust air passes to atmosphere, comprising: an annular chamber around the liner into which the exhaust port opens; a leaf spring flap damper disposed in the annular chamber in overlying relation to the exhaust port; and porting communicating the annular chamber to atmosphere; the damper being adapted to flex and oscillate relative to the exhaust port under pressure of air exhausting from the rotor chamber through the exhaust port into the annular chamber.

Claim 3

A pneumatic tool as in claim 1, wherein the damper extends parallel to the axis of the liner and is biased into overlying relation to the exhaust port.

Claim 4

A pneumatic tool as in claim 1, wherein the damper extends circumferentially with respect to the periphery of the liner and is biased into overlying relation to the exhaust port.

Claim 5

A pneumatic tool as in claim 1, wherein there are multiple exhaust ports opening through the periphery of the liner, and the damper includes multiple flexible flap fingers each biased into overlying relation with separate selected ones of the exhaust ports.

Claim 6

A pneumatic tool as in claim 1, wherein the damper is in the form of a split spring band disposed about the periphery of the liner in inwardly biased relation to the latter and having a circumferentially extending flexible flap finger biased into overlying relation to the exhaust port.

Claim 7

A pneumatic tool as in claim 1, wherein the annular chamber is an exhaust air wave modulating chamber, the liner has a plurality of exhaust ports opening from the rotor chamber through the periphery of the liner into the modulating chamber, and the damper is in the form of a split spring band disposed about the periphery of the liner in inwardly biased relation to the latter and having a plurality of circumferentially extending flap fingers each biased into overlying relation to a separate one of the exhaust ports.

Claim 8

A pneumatic tool including an air driven motor comprising a rotor liner defining a rotor chamber having an air driven multiple vane rotor operable therein and having a primary exhaust port through the liner for exhaust of driving air from the chamber; a housing for the tool encasing the motor; and a sound attenuating system through which the exhaust air passes to atmosphere comprising: an annular sound modulating chamber around the liner into which the exhaust port opens, a leaf spring flap damper having a fixed condition at one end and extending at its opposite free end into the modulating chamber in overlying relation to the exhaust port; and a final exhaust means communicating the modulating chamber through the housing to atmosphere; the damper being adapted to flex and oscillate relative to the primary exhaust port under pressure of air exhausting from the rotor chamber through the latter port.

Claim 9

A pneumatic tool including an air driven motor comprising a rotor liner defining a rotor chamber having an air driven multiple vane rotor operable therein and having a primary exhaust port through the liner for exhaust of driving air from the chamber; a housing for the tool encasing the motor; and a sound attenuating system through which the exhaust air passes to atmosphere comprising: an annular sound modulating chamber around the liner into which the exhaust port opens, a leaf spring flap damper having a fixed condition at one end and extending at its opposite free end into the modulating chamber in overlying relation to the exhaust port; and a final exhaust means communicating the modulating chamber through the housing to atmosphere; the damper being adapted to flex and oscillate relative to the primary exhaust port under pressure of air exhausting from the rotor chamber through the latter port.

Claim 10

A pneumatic tool as in claim 7, wherein the final exhaust means comprises a group of final exhaust ports through the housing located substantially diametrically to the primary exhaust port.

Claim 11

A pneumatic tool as in claim 8, wherein a screen is disposed in the modulating chamber.

Claim 12

A pneumatic tool as in claim 9, wherein the damper is inherently biased in overlying relation to the primary exhaust port.

Claim 13

A pneumatic tool as in claim 9, wherein the housing includes a main section housing the motor, and a backhead section secured against the rear of the main section; and the damper is formed of leaf spring material and is provided with a flange at its rear sandwiched between the main section and the backhead section.

Claim 14

A pneumatic tool as in claim 11, wherein the damper comprises a flap portion from the rear of which the flange is offset, and the flap portion is adapted to oscillate relative to the port in a groove formed in the main section of the housing.

Claim 15

A pneumatic tool as in claim 12, wherein the flange in an unassembled condition of the damper has an angle with the flap portion of less than 90°.