Claims
- 1. A hydraulic turning gear for imparting rotational movement to a rotor comprising:
- a ratchet wheel for attachment to the rotor;
- a pawl mechanism for engaging the ratchet wheel;
- a hydraulic cylinder connected to the pawl mechanism causing the pawl mechanism to reciprocate whereby the linear movement of the pawl mechanism causes the ratchet wheel to rotate;
- a source of relatively low pressure hydraulic fluid for driving the hydraulic cylinder;
- a booster cylinder for raising the pressure of the relatively low pressure fluid to a higher pressure sufficient to drive the hydraulic cylinder; the booster cylinder being connected to the hydraulic cylinder; and,
- valve means for directing the relatively low pressure hydraulic fluid to drive the booster cylinder, and
- wherein the hydraulic cylinder includes an arm which extends externally from the hydraulic cylinder and the pawl mechanism includes a clevis which is mounted to the hydraulic cylinder arm and a pawl which is pivotally attached to the clevis, and
- further wherein the pawl is pivotally attached to the clevis by means of a pin extending through both the pawl and the clevis, and further including means on said pin for imparting an adjustable frictional force between the pawl and the clevis whereby the pawl, once pivoted, needs a reset force to return to its original position for engaging the ratchet wheel.
- 2. The hydraulic turning gear recited in claim 1 wherein the means for imparting a frictional force between the pawl and the clevis includes a plurality of stacked Belleville washers.
- 3. The hydraulic turning gear recited in claim 1 further including stop means to limit the extent of pivot of the pawl.
- 4. The hydraulic turning gear recited in claim 1 wherein the booster cylinder includes a small diameter cylinder and a large diameter cylinder and a piston head slidably mounted in the large diameter cylinder and hydraulic fluid may be admitted on either side of the piston head to drive the piston head in a reciprocating movement; and,
- a ram attached to and following the movement of the piston head, the ram mounted, in part, in the small diameter cylinder and fluid admitted into the small diameter cylinder being pressurized by the ram.
- 5. The hydraulic turning gear recited in claim 4 wherein the valve means includes a spool valve connected between the low pressure fluid and the booster cylinder, the spool valve having alternate positions for admitting fluid to one side or the other of the piston head in the booster cylinder.
- 6. The hydraulic turning gear recited in claim 5 further comprising a pilot valve for positioning the spool valve, the pilot valve connected to the low pressure fluid source.
- 7. The hydraulic turning gear recited in claim 6 wherein the pilot valve is a solenoid valve and wherein the turning gear further includes a timer and electrical supply connected to the solenoid valve whereby the spool valve, booster cylinder, hydraulic cylinder and pawl mechanism is caused to move in preset timed manner.
- 8. A hydraulic turning gear for imparting rotational movement to a rotor comprising:
- a ratchet wheel for attachment to the rotor;
- a pawl mechanism for engaging the ratchet wheel;
- a hydraulic cylinder connected to the pawl mechanism causing the pawl mechanism to reciprocate whereby the linear movement of the pawl mechanism causes the ratchet wheel to rotate;
- a source of relatively low pressure hydraulic fluid for driving the hydraulic cylinder;
- a booster cylinder for raising the pressure of the relatively low pressure fluid to a higher pressure sufficient to drive the hydraulic cylinder; the booster cylinder being connected to the hydraulic cylinder; and,
- valve means for directing the relatively low pressure hydraulic fluid to drive the booster cylinder, and
- wherein the hydraulic cylinder includes an arm which extends externally from the hydraulic cylinder and the pawl mechanism includes a clevis which is mounted to the hydraulic cylinder arm and a pawl which is pivotally attached to the clevis, and said hydraulic gear further comprising:
- a pin attaching the pawl pivotally to the clevis;
- a plurality of stacked Belleville washers for provding a variable frictional force between the pawl and the clevis;
- a stationary guide rail for guiding the linear path of the pawl mechanism including the clevis; the guide rail also contacting the pawl to move it from a pivoted positon to a reset position.
- 9. The hydraulic turning gear recited in claim 8 wherein there is a tang attached to the pawl which contacts the guide rail when the pawl mechanism is furthest withdrawn from the ratchet wheel.
- 10. A hydraulic turning gear form imparting rotational movement to a rotor comprising:
- a ratchet wheel for attachment to a rotor;
- a pawl mechanism including a pawl element movable between ratchet wheel aligned and ratchet wheel disengagement positions;
- hydraulic means including a piston rod for linearly moving said pawl mechanism toward and away from said ratchet wheel, said pawl element operatively connected by pin means to one end of said piston rod for pivotal movement relative to said piston rod, said pawl element being operable to engage and rotate said ratchet wheel upon extension of said piston rod with the pawl element in the ratchet wheel aligned position; and
- adjustable friction means mounted on said pin means for holding said pawl element in said ratchet wheel disengagement position.
- 11. A hydraulic turning gear as defined in claim 10 wherein said ratchet wheel includes surface means for moving said pawl element from said ratchet wheel aligned position to said ratchet wheel disengagement position upon extension of said piston rod and rotation of said ratchet wheel.
- 12. A hydraulic turning gear as defined in claim 10 and further including stationary guide means for moving said pawl element to said ratchet wheel disengagement position upon retraction of said piston rod.
- 13. A hydraulic turning gear comprising:
- a ratchet wheel for attachment to a turbine rotor;
- a pawl mechanism for selectively engaging the ratchet wheel, the pawl mechanism operating in a linear reciprocating manner;
- a hydraulic cylinder attached to the pawl mechanism;
- a hydraulic booster cylinder fluidly connected to the hydraulic cylinder for supplying high pressure fluid to the hydraulic cylinder;
- a spool valve having two operating positions for supplying low pressure fluid to the hydraulic booster cylinder whereby the hydraulic booster cylinder moves in a reciprocating manner; and,
- a pilot valve for positioning the spool valve, the pilot valve and the spool valve being connected to a source of low pressure hydraulic fluid.
- 14. A hydraulic turning gear comprising:
- a ratchet wheel attachable to a rotor;
- a hydraulic cylinder having a piston mounted within the hydrualic cylinder and a piston rod extending outside the hydraulic cylinder;
- a pawl mechanism including a pawl and clevis mounted to the piston rod; the pawl being pivotally mounted to the clevis with an adjustable friction force therebetween;
- a guide rail mounted to the hydraulic cylinder and the clevis being slidable with respect to the guide rail whereby the pivotal pawl is pivoted away from the ratchet wheel after initial contact therewith and is reset by the guide rail.
Government Interests
This invention was made in the course of Government Contract No. N00024-83-C-4181 (Prime) and N3352-766 (Subcontract) for the United States Navy and rights to the invention are determined by the provisions in those contracts.
US Referenced Citations (9)