Semi-rotary hydraulic actuator

Details Semi-rotary hydraulic actuator Semi-rotary hydraulic actuator

2000-04-13

2001-09-18

Look, Edward K. (Department: 3745)

Expansible chamber devices

With flexible transmission element secured to working member

C092S138000, C092S140000

Reexamination Certificate

active

06289788

ABSTRACT:

FIELD OF INVENTION
This invention relates to a semi-rotary hydraulic actuator adapted to rotate a shaft over 180°.
BACKGROUND ART
Current methods of rotating a shaft by hydraulic means include the linear actuator and crank arm system which has the disadvantage that the angle of rotation is limited to little over 90°. Furthermore, the velocity and power output varies significantly due to the increase and decrease in the crank arm's perpendicular length.
Another system for rotating a shaft about a pivot point is the rack and pinion actuator which does provide constant velocity and power output but is expensive to manufacture and has poor shock load capacity because the entire reaction force is against one tooth.
The vane-type actuator offers constant velocity but is also expensive to manufacture and suffers from inability to hold a load because of high leakage rates. Furthermore, the vane actuator is unable to sustain end of stroke shock loads.
Another prior art method of rotating a shaft about a pivot point is the linear actuator and chain drive which possesses the low cost benefit of the linear actuator and the constant velocity of the rack and pinion by using opposed cylinders to pull a chain which is engaged in a sprocket. However, this arrangement requires a very large space because of the extended length of the cylinders.
It is therefore, an object of the invention to provide an improved rotary hydraulic actuator for rotating a shaft around a pivot point which provides 180° of rotation.
SUMMARY OF INVENTION
According to the invention there is provided an actuator for rotating a shaft comprising:
(i) a housing having a first port, a second port and a drive track therein,
(ii) a first drive means coupled to the first port and a second drive means coupled to the second port,
(iii) an array of balls adjacent ones of which are spaced apart by a spacer to define a drive train extending from one drive means to the other drive means via the drive track,
(iv) a drive pin extending outwardly from the shaft connected to the drive train, and
(v) means for moving the first and second drive means so that the drive train rotates the drive pin and hence the shaft.


REFERENCES:
patent: 3448626 (1969-06-01), Yeatman et al.
patent: 3965802 (1976-06-01), Jacobs
patent: 4317505 (1982-03-01), Schneider

Affiliated with

Also associated with

Rating

Semi-rotary hydraulic actuator does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Semi-rotary hydraulic actuator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semi-rotary hydraulic actuator will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2545505