Ball and piston rotary actuator mechanism

1. A rotary actuator mechanism for applying torque to a shaft and comprising:

(a) an actuator housing forming an actuator path including a curved portion;

(b) an actuator pinion rotatably supported in said housing and having said shaft secured thereto, said pinion having peripheral notches of a selected shape and positioned within said curved portion of said actuator path;

(c) a train of discrete actuator elements having opposite ends and positioned in said actuator path, each of said actuator elements being of said selected shape to enable reception in said peripheral notches, a plurality of said elements engaging said notches;

(d) said path being formed in part by a block extending into said pinion to position a surface thereof closely adjacent said shaft to thereby guide said actuator elements into engagement with said notches of said pinion and from said notches into another portion of said path; and

(e) at least one linear actuator supported by said housing and engaging one of said ends of said train of actuator elements, said linear actuator being selectively activated to push said train of discrete actuator elements through said actuator path to thereby serially engage said actuator elements with said notches of said pinion and thereby apply torque to said shaft.

2. A rotary actuator mechanism for applying torque to a shaft and comprising:

(a) an actuator housing forming a U-shaped path including a pair of straight portions connected by a curved portion;

(b) an actuator pinion rotatably supported in said housing and having said shaft secured thereto, said pinion having peripheral notches of a selected shape and positioned within said curved portion of said U-shaped path;

(c) a train of discrete actuator elements having opposite ends and positioned in said U-shaped path, each of said actuator elements being of said selected shape to enable reception in said peripheral notches, at least one of said actuator elements engaging one of said notches;

(d) said path being formed in part by a block extending into said pinion to position a surface thereof closely adjacent said shaft to thereby guide said actuator elements into engagement with said notches of said pinion and from said notches into said straight portions of said path; and

(e) a pair of linear actuators supported by said housing and engaging said opposite ends of said train of actuator elements, said linear actuators being selectively and alternately activated to reversibly push said train of discrete actuator elements through said U-shaped path to thereby serially engage said actuator elements with said notches of said pinion and thereby apply torque to said shaft.

3. A mechanism as set forth in claim 2 wherein:

(a) each of said discrete actuator elements is spherical in shape; and

(b) said peripheral notches of said actuator pinion are spherical in shape and sized to received the spherical actuator elements.

4. A mechanism as set forth in claim 2 wherein:

(a) said pair of linear actuators are positioned on a common side of said housing to provide a compact rotary actuator mechanism.

5. A mechanism as set forth in claim 2 wherein:

(a) said pair of linear actuators are positioned in spaced apart parallel relation on a common side of said housing to provide a compact rotary actuator mechanism.

6. A mechanism as set forth in claim 2 wherein:

(a) each of said linear actuators is a hydraulic actuator including a piston engaging a respective end of said train of actuator elements.

7. A mechanism as set forth in claim 2 and including:

(a) said housing being secured to a robotic arm member;

(b) a support structure being secured to said shaft; and

(c) said robotic arm member being pivoted relative to said support structure by selective application of torque to said shaft.

8. A mechanism as set forth in claim 2 and including:

(a) a first robotic arm member having said actuator housing secured thereto; and

(b) a second robotic arm member secured to said shaft and pivotable with respect to said first robotic arm by selective application of torque to said shaft.

9. A robotic arm assembly for generating relative pivoting motion between a robotic arm member and a second structure and comprising:

(a) an elongated robotic arm member;

(b) a second structure;

(c) a rotary actuator mechanism engaged between said robotic arm member and said second structure, said rotary actuator mechanism including:

(1) an actuator housing forming a U-shaped path including a pair of straight portions and connected by a curved portion, said housing being secured to said robotic arm member;

(2) an actuator pinion rotatably supported in said housing and having an actuator shaft secured thereto, said pinion having peripheral notches of a selected shape and positioned within said curved portion of said U-shaped path;

(3) a train of discrete actuator elements having opposite ends and positioned in said U-shaped path, each of said actuator elements being of said selected shape to enable reception in said peripheral notches, a plurality of said elements engaging said notches;

(4) said path being formed in part by a block extending into said pinion to position a curved surface thereof closely adjacent said shaft to thereby guide said actuator elements into engagement with said notches of said pinion and from said notches into one of said straight Portions of said path; and

(5) a pair of linear actuators supported by said housing and engaging said opposite ends of said train of actuator elements, said pair of linear actuators being positioned within said robotic arm member and said linear actuators being selectively and alternately activated to reversibly push said train of discrete actuator elements through said U-shaped path to thereby serially engage said actuator elements with said notches of said pinion and thereby apply torque to said shaft; and

(d) said actuator mechanism generating said relative pivoting motion between said robotic arm member and said second structure by selective application of said torque to said shaft.

10. An assembly as set forth in claim 9 wherein:

(a) said robotic arm member is a first robotic arm member; and

(b) said second structure is a second robotic arm member.

11. An assembly as set forth in claim 9 wherein:

(a) each of said discrete actuator elements is spherical in shape; and

(b) said peripheral notches of said actuator pinion are spherical in shape and sized to received the spherical actuator elements.

12. An assembly as set forth in claim 9 wherein:

(a) each of said linear actuators is a hydraulic actuator including a piston engaging a respective end of said train of actuator elements; and

(b) said hydraulic actuators are positioned in spaced apart parallel relation.

13. A rotary actuator mechanism for applying torque to a shaft and comprising:

(a) an actuator housing forming a U-shaped path including a curved portion and a straight portion;

(b) an actuator pinion rotatably supported in said housing and having said shaft secured thereto, said pinion having peripheral notches of a spherical shape and positioned within said curved portion of said U-shaped path;

(c) a train of discrete spherical actuator elements having opposite ends and positioned in said U-shaped path, each of said actuator elements being sized to enable reception in said peripheral notches of said pinion, a plurality of said elements engaging said notches;

(d) said path being formed in part by a block extending into said pinion to position a curved surface thereof closely adjacent said shaft to thereby guide said actuator elements into engagement with said notches of said pinion and from said notches into said straight portion of said path; and

(e) a pair of linear hydraulic actuators supported by said housing and having respective hydraulic pistons engaging said opposite ends of said train of spherical actuator elements, said hydraulic actuators being selectively and alternately activated to reversibly push said train of spherical actuator elements through said U-shaped path to thereby serially engage said actuator elements with said notches of said pinion and thereby apply torque to said shaft.

14. A mechanism as set forth in claim 13 wherein:

(a) said pair of hydraulic actuators are positioned on a common side of said housing to provide a compact rotary actuator mechanism.

15. A mechanism as set forth in claim 13 wherein:

(a) said pair of hydraulic actuators are positioned in spaced apart parallel relation on a common side of said housing to provide a compact rotary actuator mechanism.

16. A mechanism as set forth in claim 13 and including:

(a) said housing being secured to a robotic arm member;

(b) a support structure being secured to said shaft; and

(c) said robotic arm member being pivoted relative to said support structure by selective application of torque to said shaft.

17. A mechanism as set forth in claim 13 and including:

(a) a first robotic arm member having said actuator housing secured thereto; and

(b) a second robotic arm member secured to said shaft and pivotable with respect to said first robotic arm by selective application of torque to said shaft.

18. A robotic arm assembly for generating relative pivoting motion between a robotic arm member and a second structure and comprising:

(a) an elongated robotic arm member;

(b) a second structure;

(c) a rotary actuator mechanism engaged between said robotic arm member and said second structure, said rotary actuator mechanism including:

(1) an actuator housing forming a U-shaped path including a pair of straight portions positioned in spaced apart parallel relation and connected by a curved portion, said housing being secured to said robotic arm member;

(2) an actuator pinion rotatably supported in said housing and having said shaft secured thereto, said pinion having peripheral notches of a spherical shape and positioned within said curved portion of said U-shaped path;

(3) a train of discrete spherical actuator elements having opposite ends and positioned in said U-shaped path, each of said actuator elements being sized to enable reception in said peripheral notches of said pinion, a plurality of said elements engaging said notches;

(4) said path being formed in part by a block extending into said pinion to position a curved surface thereof closely adjacent said shaft to thereby guide said actuator elements into engagement with said notches of said pinion and from said notches into one of said straight portions of said path; and

(5) a pair of linear hydraulic actuators supported by said housing and having respective hydraulic pistons engaging said opposite ends of said train of spherical actuator elements, said hydraulic actuators being positioned within said robotic arm member and said hydraulic actuators being selectively and alternately activated to reversibly push said train of spherical actuator elements through said U-shaped path to thereby serially engage said actuator elements with said notches of said pinion and thereby apply torque to said shaft; and

(d) said actuator mechanism generating said relative pivoting motion between said robotic arm member and said second structure by selective application of said torque to said shaft.

19. An assembly as set forth in claim 18 wherein:

(a) said robotic arm member is a first robotic arm member; and

(b) said second structure is a second robotic arm member.