Electrically Actuated Robotic Tool Changer

Abstract

A robotic tool changer comprises first and second units, operative to be separately attached to a robot and a robotic tool, and further operative to be selectively coupled together and decoupled. The first and second units are coupled and decoupled by an electric motor. Power from the electric motor may be applied to couple and decouple the first and second units in a variety of ways.

Description

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective rendering of a robotic tool changer with an electrical signal utility module attached.

FIG. 2 is a perspective rendering of a motor, drive train, and worm gear arrangement of selected components of a robotic tool changer master module.

FIG. 3 is a partial sectional diagram of the worm gear drive train of a robotic tool changer master module.

FIG. 4 is a perspective rendering of a motor, drive train, and scissor gear arrangement of selected components of a robotic tool changer master module.

FIG. 6 is a partial sectional diagram of an oppositely-threaded shaft and trunnion nut drive train of a robotic tool changer master module.

FIG. 6 is a perspective rendering of selected components of the trunnion nut drive train of FIG. 5.

FIG. 7 is a perspective rendering of a robotic tool changer with electrical signal and pneumatic utility modules attached.

FIG. 8 is a perspective rendering of a robotic tool changer with a translucent housing depicting a motor coupling and worm drive train.

FIG. 9 is a partial sectional view of a robotic tool changer with an electrically actuated locking shaft.

FIG. 10 is a plan view of a robotic tool changer in a mated but not coupled position.

FIG. 11 is a perspective rendering of a robotic tool changer with a pneumatic utility module attached.

FIG. 12 is an exploded perspective rendering of selected components of a robotic tool changer master module.

FIG. 13 is a perspective rendering of selected components of a robotic tool changer master module.

FIG. 14 is a sectional view of selected portions of the robotic tool changer of FIG. 11 in a coupled position.

Claims

1. A robotic tool changer, comprising: a first unit operative to be attached to one of a robot and a robotic tool;a second unit operative to be attached to the other of the robot and a robotic tool, and further operative to be selectively coupled to and decoupled from the first unit;a coupling mechanism disposed in the first unit and operative to selectively couple the first and second units in a coupled position and to allow the first and second units to decouple in a decoupled position, andan electric motor operative to drive the coupling mechanism between coupled and decoupled positions.

2. The tool changer of claim 1 wherein the coupling mechanism comprises: a plurality of rolling members disposed in the one of the units;a piston disposed in the first unit, the piston selectively movable along a longitudinal axis between a retracted, decoupled position and an extended, coupled position, the piston having at least one tapered surface operative to displace the rolling members outwardly of the piston axis as the piston moves from the decoupled to the coupled position; andat least one angled surface in the second unit operative to lock the first and second units together when the rolling members are forced against the angled surface by a tapered piston surface.

3. The tool changer of claim 2 wherein the rolling members are disposed generally circumferentially around the piston axis.

4. The tool changer of claim 3 wherein the rolling members are operative to roll in a generally radial direction with respect to the piston axis.

5. The tool changer of claim 4 wherein the rolling members comprise balls.

6. The tool changer of claim 4 wherein the rolling members comprise cylinders.

7. The tool changer of claim 2 wherein the at least one tapered surface comprises: a tapered locking surface;an initial actuating surface; anda failsafe surface interposed between said tapered locking surface and said initial actuating surface.

8. The tool changer of claim 7 wherein the initial actuating surface has an angle with respect to the piston axis not greater than the angle of the tapered locking surface.

9. The tool changer of claim 7 wherein the initial actuating surface has an angle with respect to the piston axis equal to or greater than the angle of the tapered locking surface.

10. The tool changer of claim 2 further comprising a coupling mechanism coupling the electric motor to the piston and operative to move the piston between a retracted, decoupled position and an extended, coupled position.

11. The tool changer of claim 10 wherein the coupling mechanism comprises: a motor output shaft connected to the electric motor, the motor output shaft including worm threads;a worm gear disposed coaxially with the piston and having a threaded inner surface, the worm gear coupled to the motor output shaft worm threads; anda threaded shaft connected to the piston, the threaded shaft coupled to the threaded inner surface of the worm gear.

12. The tool changer of claim 11 wherein the worm gear is constrained in the axial direction and imparts an axial force on the threaded shaft via the threaded inner surface as it is turned by the worm threads of the electric motor output shaft.

13. The tool changer of claim 10 wherein the coupling mechanism comprises: a threaded motor output shaft connected to the electric motor;a threaded nut threaded onto the threaded shaft; anda scissors linkage connected to the threaded nut and operative to displace the piston between a retracted, decoupled position and an extended, coupled position as the threaded nut moves along the threaded shaft as the threaded shaft is driven by the electric motor.

14. The tool changer of claim 10 wherein wherein the coupling mechanism comprises: a shaft driven by the electric motor, the shaft having two oppositely-threaded portions;a threaded nut threaded onto each shaft portion; anda connecting rod connected to each threaded nut and pivotally connected to the piston, the connecting rods operative to displace the piston between a retracted, decoupled position and an extended, coupled position as the shaft rotates.

15. The tool changer of claim 14 wherein, as the electric motor turns the shaft in one direction, each threaded nut moves outwardly towards a respective end of the shaft, and the connecting rods move the piston towards the retracted, decoupled position, and as the electric motor turns the shaft in the opposite direction, each threaded nut moves inwardly towards the center of the shaft, and the connecting rods move the piston towards the extended, coupled position.

16. The tool changer of claim 10 wherein the coupling mechanism comprises: a gear driven by the electrical motor and having a plurality of cam followers protruding from the inner surface; anda piston shaft connected to the piston and having a corresponding plurality of variable helix cam grooves formed on the outer surface thereof, the shaft having a non-circular central bore formed axially therein; anda non-circular spline post rigidly attached to the first unit and shaped to mate with the piston shaft bore and operative to prevent rotational motion of the piston shaft;wherein the shaft is disposed over the spline post and within the driven gear, with a cam follower disposed in each variable helix cam groove, so as to displace the piston between a retracted, decoupled position and an extended, coupled position as the driven gear rotates.

17. The tool changer of claim 16 further comprising a motor output shaft having worm threads engaging the driven gear, and wherein the gear is driven by the electrical motor via the motor output shaft.

18. The tool changer of claim 16 wherein the driven gear is driven by the electric motor via a belt member.

19. The tool changer of claim 1: wherein the coupling mechanism comprises a locking shaft having a plurality of thread ledge lobes disposed radially around the shaft, each thread ledge lobe comprising a plurality of thread ledges arranged in an axial orientation on the locking shaft; andfurther comprising a corresponding plurality of thread shelf sets disposed radially around an interior annular surface of a cavity formed in the second unit, each thread shelf set comprising a plurality of thread shelves arranged in an axial orientation.

20. The tool changer of claim 19 wherein, in the decoupled position of the locking shaft, the thread ledge lobes align with spaces between the thread shelf sets, allowing the first and second units to decouple, and in the coupled position of the locking shaft, the thread ledges engage with the thread shelves, coupling the first and second units together.

21. The tool changer of claim 20 wherein the locking shaft includes three thread ledge lobes disposed substantially evenly around the circumference of the locking shaft.

22. The tool changer of claim 20 further comprising: a motor output shaft having worm threads, the motor output shaft driven by the electric motor;a worm gear coupled to the locking shaft and engaging the motor output shaft worm threads such that as the motor drives the motor output shaft, the worm gear rotates the locking shaft.

23. A robotic tool changer, comprising: a tool unit operative to attach to a robotic tool and including a generally circular chamber;a master unit operative to attach to a robot, and to selectively couple to and decouple from the tool unit;an annular collar on the master unit, having a plurality of holes formed therethrough;a plurality of ball members disposed within the holes;a piston having at least one tapered surface disposed in the master unit, the piston operative to urge the ball members radially outward of the collar as the the piston moves from a retracted, decoupled position to an extended, coupled position;an electric motor;a coupling mechanism operative to selectively move the piston between decoupled and coupled positions in response to the electric motor; andan angled surface in the tool unit chamber opposite each collar hole when the master and tool units are abutted, the angled surface operative to direct a component of the force applied to it by the ball members towards the master unit.

24. The tool changer of claim 23 wherein the at least one tapered surface comprises: a tapered locking surface;an initial actuating surface; anda failsafe surface interposed between said tapered locking surface and said initial actuating surface.

25. The tool changer of claim 23 wherein the coupling mechanism comprises: a motor output shaft connected to the electric motor, the motor output shaft including worm threads;a worm gear disposed coaxially with the piston, constrained in the axial direction, and having a threaded inner surface, the worm gear coupled to the motor output shaft worm threads; anda threaded shaft connected to the piston, the threaded shaft coupled to the threaded inner surface of the worm gear.

26. The tool changer of claim 23 wherein the coupling mechanism comprises: a threaded motor output shaft connected to the electric motor;a threaded nut threaded onto the threaded shaft; anda scissors linkage connected to the threaded nut and operative to displace the piston between a retracted, decoupled position and an extended, coupled position as the threaded nut moves along the threaded shaft as the threaded shaft is driven by the electric motor.

27. The tool changer of claim 23 wherein the coupling mechanism comprises: a shaft driven by the electric motor, the shaft having two oppositely-threaded portions;a threaded nut threaded onto each shaft portion; anda connecting rod connected to each threaded nut and pivotally connected to the piston, the connecting rods operative to displace the piston between a retracted, decoupled position and an extended, coupled position as the shaft rotates.

28. The tool changer of claim 23 wherein the coupling mechanism comprises: a gear driven by the electrical motor and having a plurality of cam followers protruding from the inner surface; anda piston shaft connected to the piston and having a corresponding plurality of variable helix cam grooves formed on the outer surface thereof, the shaft having a non-circular central bore formed axially therein; anda non-circular spline post rigidly attached to the first unit and shaped to mate with the piston shaft bore and operative to prevent rotational motion of the piston shaft;wherein the shaft is disposed over the spline post and within the driven gear, with a cam follower disposed in each variable helix cam groove, so as to displace the piston between a retracted, decoupled position and an extended, coupled position as the driven gear rotates.

29. A method of selectively coupling two robotic tool coupler units, comprising: abutting the two units; andactuating an electric motor to couple the two units together.

30. A robotic tool changer, comprising: a tool unit operative to attach to a robotic tool and including a generally circular chamber;a master unit operative to attach to a robot, and to selectively couple to and decouple from the tool unit;a locking shaft connected to the master unit and protruding therefrom, the locking shaft having a plurality of thread ledge lobes disposed radially around the shaft, each thread ledge lobe comprising a plurality of thread ledges arranged in an axial orientation on the locking shaft;an electric motor disposed on the master unit and operative to selectively rotate the locking shaft; anda plurality of thread shelf sets disposed radially around an interior annular surface of the tool unit chamber, each thread shelf set comprising a plurality of thread shelves arranged in an axial orientation;wherein when the master and tool units are abutted, the locking shaft extends within the tool unit chamber with the thread ledge lobes in spaces between the thread shelf sets in a decoupled position; andwherein when the electric motor rotates the locking shaft to a coupled position, the thread ledges engage and lock with corresponding thread shelves, coupling the master and tool units together.

31. A robotic tool changer, comprising: a first unit operative to be attached to one of a robot and a robotic tool;a second unit operative to be attached to the other of the robot and a robotic tool, and further operative to be selectively coupled to and decoupled from the first unit;an electric motor;means for selectively coupling the first and second units in a coupled position and to allow the first and second units to decouple in a decoupled position under the power of the electric motor.