초록 ▼

An air turbine starter for use in starting a turbine engine includes a pawl and ratchet clutch having a movable member which selectively prevents engagement of the clutch while providing a pawl raceway surface, or allows clutch engagement. No-load acceleration of the air turbine starter is scheduled

An air turbine starter for use in starting a turbine engine includes a pawl and ratchet clutch having a movable member which selectively prevents engagement of the clutch while providing a pawl raceway surface, or allows clutch engagement. No-load acceleration of the air turbine starter is scheduled to ensure that drop-in speed of the centrifugally responsive pawls is not reached by the ratchet member while clutch engagement is being permitted. The movable member is pneumatically controlled in timed coordination with acceleration of the air turbine starter to prevent crash engagement of the clutch. Clutch ratcheting is also substantially prevented.

대표청구항 ▼

The method of operating an air turbine starter in conjunction with a combustion turbine engine, said method comprising the steps of; providing a pawl and ratchet clutch between said air turbine starter and a rotatable shaft of said combustion turbine engine, and thereby drivingly connecting the form

The method of operating an air turbine starter in conjunction with a combustion turbine engine, said method comprising the steps of; providing a pawl and ratchet clutch between said air turbine starter and a rotatable shaft of said combustion turbine engine, and thereby drivingly connecting the former to the latter for starting of said engine; connecting a ratchet wheel of said pawl and ratchet clutch to said air turbine starter for rotation in unison therewith; connecting a pawl hub portion of said pawl and ratchet clutch to said shaft of said combustion turbine engine for rotation in unison therewith; configuring said pawl and ratchet clutch to include centrifugally responsive pawl members carried by said pawl hub portion and drivingly connecting the latter to said ratchet wheel, and moving out of engagement with said ratchet wheel in response to rotation of said engine shaft; providing yieldable means biasing said pawl members into engagement with said ratchet wheel in opposition to centrifugal force to establish a pawl drop in speed of said shaft at which speed said pawl members move into engagement with said ratchet wheel during deceleration of said engine shaft; providing an engagement blocking member in a first position preventing engagement of said pawl members with said ratchet wheel; providing means moving said engagement blocking member to a second position only for a selected interval immediately following initiation of air turbine starter operation, in said second position said pawls being engagable with said ratchet wheel; and scheduling the no-load acceleration rate of said air turbine starter from rest so that said pawl drop in speed is not attained by said ratchet wheel during said selected interval.