Speed governor for a pneumatic power tool
AssigneeAtlas Copco Tools AB
InventorRolf A. Jacobsson
Life of this patent
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Abstract
A speed governor for a pneumatic power tool which comprises a housing (10) with pressure air supply means (16-18) and an air turbine (20) including a turbine wheel (22) drivingly coupled to an output spindle and a number of air nozzles (25) for directing motive pressure air onto the turbine wheel (22), wherein the speed governor comprises a flow controlling valve element (43) associated with an activation piston (44) for adjusting the valve element (43) in response to a control pressure obtained in a pressure sensing opening (34) located opposite an idle running nozzle (28) downstream of the turbine wheel (22).
Claims5
In a speed governor for a pneumatic power tool including a housing (10) with a pressure air inlet passage (16), a rotating output spindle, an air turbine (20) including a turbine wheel (22) drivingly coupled to said output spindle and one or more air nozzles (25) in said housing (10) for directing motive pressure air onto said turbine wheel (22), said speed governor comprising a valve element (43) arranged to control the pressure air flow through said inlet passage (16) and a valve element (43) activating piston means (44) exposed to a speed responsive control pressure,
- the improvement comprising:
- a separate idle running nozzle (28),
- an idle flow supply passage (29) extending from said air inlet passage (16) to said idle running nozzle (28),
- a control pressure passage (35), and
- a pressure sensing opening (34) located substantially opposite said idle running nozzle (28) downstream of said turbine wheel (22),
- said control pressure passage (35) connecting said pressure sensing opening (34) with said piston means (44) so as to make said piston means (44) activate said valve element (43) in response to said turbine speed responsive control pressure prevailing in said pressure sensing opening (34).
Dependencies are inferred from the claim text.