SYSTEMS AND METHODS FOR DISENGAGING AND ENGAGING A WRAP SPRING CLUTCH

• US 20110198184A1
• Filed: 02/16/2011
• Published: 08/18/2011
• Est. Priority Date: 02/17/2010
• Status: Active Grant

• Current Assignee: Raven Industries Incorporated (CNH Industrial N.V.)
• Original Assignee: Raven Industries Incorporated (CNH Industrial N.V.)
• Inventors: Barry, Alan F.
• Granted Patent: US 8,869,964 B2
• Time in Patent Office: Days
• US Class Current: 192/71
• CPC Class Codes: F16D 13/025 with a helical band or equivalent member with two or more turns embracing a drum or the like electromagnetically actuated F16D27/105
• CPC Class Codes: F16D 27/105 with a helical band or equivalent member co-operating with a cylindrical coupling surface

Abstract

The invention provides a system, device and method for using a rotary actuator, e.g., a stepper motor to actuate a wrap spring clutch. Feedback from a system of sensors and GPS data, including rotational speed, travel speed and direction are provided to improve the reaction accuracy of the clutch. In one embodiment, a plurality of actuator controllers are connected in a configuration wherein one controller is a “master” and the remaining controllers are “slaves” to provide a higher level of machine control.

Claims

1. A wrap spring clutch assembly comprising:

an input drive shaft in operative connection with a first clutch plate;

an output drive shaft in operative connection with a second clutch plate, wherein the first and second clutch plates are adjacent one another;

a torsion wrap spring compressed against and wrapped around a portion of the first and second clutch plates, the torsion wrap spring comprising a tang projecting radially outwardly from the wrapped torsion wrap spring;

a stepper motor actuator assembly comprising

an eccentric comprising an off center axle in operative connection with the gear reduction mechanism, the eccentric rotationally driven by the stepper motor;

a mechanical link connected with the axle of the eccentric, the mechanical link transforming the rotational driving of the eccentric into linear movement of the mechanical link;

a plunger operatively connected with the mechanical link, the plunger translating linearly in response to the linear movement of the mechanical link,

wherein the stepper motor actuator assembly may provide 360 degrees of rotational motion for the eccentric, with a corresponding translational positions for the plunger, whereby, the plunger may engage the tang of the torsion wrap spring in at least a first translational position and may not engage the tang of the torsion wrap spring in at least a second translational position.

2. The assembly of claim 1, wherein the engagement of the tang with the plunger comprises disengagement of the torsion wrap spring from the portion of the first and second clutch plates and disengaging the output drive shaft from the input drive shaft.

3. The assembly of claim 1, wherein the at least second translational position of the plunger comprises a disengagement of the plunger with the tang of the torsion wrap spring comprising an engagement of the torsion wrap spring with the first and second clutch plates and engagement of the output drive shaft with the input drive shaft.

4. The assembly of claim 1, further comprising a stepper motor controller in operative communication and connection with the stepper motor, the stepper motor programmed to rotate the eccentric a number of rotational degrees to achieve a desired engagement rotational position in order to engage the tang with the plunger.

5. The assembly of claim 4, wherein the desired engagement rotational position comprises a rotational position of 90 degrees to 270 degrees.

6. The assembly of claim 5, further the stepper motor further programmed to rotate the eccentric a number of rotational degrees to achieve a desired disengagement rotational position in order to disengage the tang from the plunger.

7. The assembly of claim 6, wherein the desired disengagement rotational position comprises a rotational position of 271 degrees to 89 degrees.

8. The assembly of claim 7, wherein the stepper motor controller determines the length of time the tang is engaged with the plunger and the length of time the tang is disengaged with the plunger.

9. The assembly of claim 8, further comprising a first sensor in operative communication with the stepper motor controller for measuring the rotational position data of the eccentric, the measured rotational position data communicated back to the stepper motor controller.

10. The assembly of claim 9, the first sensor further measuring the rotational speed data of the output drive shaft, the measured rotational speed data communicated back to the stepper motor controller.

11. The assembly of claim 10, a second sensor in operative communication with the stepper motor controller for measuring the rotational speed data of the input drive shaft, the measured rotational speed data communicated back to the stepper motor controller.

12. The assembly of claim 11, further comprising a Global Positioning System (“

GPS”

) in operative communication with the stepper motor controller.

13. The assembly of claim 12, further comprising the stepper motor controller being programmed to engage the plunger with the tang of the torsion wrap spring for a predetermined number of revolutions of the input hub and to disengage the plunger from the tang of the torsion wrap spring for a predetermined number of revolutions of the output hub.

14. The assembly of claim 12, further comprising the stepper motor controller using the measured rotational speed and rotational position data for determining when to engage the plunger with the tang of the torsion wrap spring and when to disengage the plunger from the tang of the torsion wrap spring.

15. The assembly of claim 4, further comprising a power buss, the power buss providing continuous power to the stepper motor controller and the stepper motor and whereby a pulse width modulated signal is generated and applied to control the engagement and disengagement of the plunger and the tang of the torsion wrap spring.

16. The assembly of claim 15, wherein the output hub is driven at a rotational speed determined by the travel speed, the travel speed data provided by the GPS.

17. The assembly of claim 16, further comprising a master control unit in operative communication with the stepper motor controller and the GPS, first and second sensors and capable of determining position, speed and direction, wherein the master control unit signals the stepper motor controller'"'"'s engagement of the tang of the torsion spring with the plunger and the disengagement of the tang of the torsion spring with the plunger.

18. The assembly of claim 1, wherein eccentric further comprises a stop arm extending radially outwardly from eccentric and in rotating communication with eccentric;

an upper stop and a lower stop in operative communication with the stop arm of the eccentric, wherein engagement of the stop arm with either the upper stop or the lower stop requires a reversal of rotational direction by the eccentric to translate the plunger.

19. A system of actuator controllers for providing an improved level of machine control, comprising:

providing a plurality of actuable machines;

providing a wrap spring clutch assembly in operative connection and communication with each of the plurality of actuable machines, comprising;

an input drive shaft in operative connection with a first clutch plate;

an output drive shaft in operative connection with a clutch input hub, wherein the first and second clutch plates are adjacent one another;

a torsion wrap spring compressed against and wrapped around a portion of the first and second clutch plates, the torsion wrap spring comprising a tang positioned radially outwardly from the wrapped torsion wrap spring;

providing a stepper motor actuator assembly for each wrap spring clutch assembly, comprising;

a gear reduction mechanism;

an eccentric comprising an off center axle in operative connection with the gear reduction mechanism, the eccentric rotationally driven by the stepper motor;

a mechanical link connected with the eccentric, the mechanical link transforming the rotational driving of the eccentric into translational movement of the mechanical link;

a plunger operatively connected with the mechanical link, the plunger translating in response to the translational movement of the mechanical link,

wherein the stepper motor actuator assembly may provide 360 degrees of rotational motion for the eccentric, with a corresponding translational positions for the plunger, whereby, the plunger may engage the tang of the torsion wrap spring in at least a first translational position and may not engage the tang of the torsion wrap spring in at least a second translational position,

wherein the engagement of the tang with the plunger comprises disengagement of the torsion wrap spring from the portion of the first and second clutch plates and disengaging the output drive shaft from the input drive shaft, and wherein the at least second translational position of the plunger comprises a disengagement of the plunger with the tang of the torsion wrap spring comprising an engagement of the torsion wrap spring with the first and second clutch plates and engagement of the output drive shaft with the input drive shaft; and

providing one or more slave stepper motor controllers in operative communication and connection with the stepper motor, the stepper motor capable of rotation of the eccentric a number of rotational degrees to achieve a desired engagement rotational position in order to engage or disengage the tang with the plunger; and

providing a master control unit in operative communication with each slave stepper motor controller, the master control unit capable of receiving programming and sensor data and controlling each slave stepper motor controller.

20. The system of claim 19, further comprising a first sensor in operative communication with the master control unit for measuring the rotational position data of each eccentric, the measured rotational position data communicated back to the master control unit.

21. The assembly of claim 20, the first sensor further measuring the rotational speed data of each output drive shaft, the measured rotational speed data communicated back to the master control unit.

22. The assembly of claim 21, a second sensor in operative communication with the master control unit for measuring the rotational speed data of each input drive shaft, the measured rotational speed data communicated back to the master control unit.

23. The assembly of claim 22, further comprising a Global Positioning System (“

GPS”

) in operative communication with the master control unit.

24. The assembly of claim 22, further comprising the master control unit, each slave controller and each stepper motor operatively connected with a power buss, whereby a pulse width modulated signal is generated and applied to control the engagement and disengagement of the plunger and the tang of the torsion wrap spring.

25. A wrap spring clutch assembly comprising:

an input drive shaft in operative connection with a first clutch plate;

an output drive shaft in operative connection with a second clutch plate, wherein the first and second clutch plates are adjacent one another;

a torsion wrap spring compressed against and wrapped around a portion of the first and second clutch plates, the torsion wrap spring comprising a tang projecting radially outwardly from the wrapped torsion wrap spring;

an actuator assembly comprising;

a rotary motor,

an eccentric comprising an off center axle in operative connection with the gear reduction mechanism, the eccentric rotationally driven by the rotary motor;

a mechanical link connected with the axle of the eccentric, the mechanical link transforming the rotational driving of the eccentric into linear movement of the mechanical link;

a plunger operatively connected with the mechanical link, the plunger translating linearly in response to the linear movement of the mechanical link,

wherein the actuator assembly may provide 360 degrees of rotational motion for the eccentric, with a corresponding translational positions for the plunger, whereby, the plunger may engage the tang of the torsion wrap spring in at least a first translational position and may not engage the tang of the torsion wrap spring in at least a second translational position.

26. A wrap spring clutch assembly comprising:

an input drive shaft in operative connection with a first clutch plate;

an output drive shaft in operative connection with a second clutch plate, wherein the first and second clutch plates are adjacent one another;

a torsion wrap spring compressed against and wrapped around a portion of the first and second clutch plates, the torsion wrap spring comprising a tang projecting radially outwardly from the wrapped torsion wrap spring;

a control sleeve capable of engaging and disengaging the tang, comprising a series of radial catches arranged radially around control sleeve;

a motor assembly comprising;

a rotary motor comprising a motor shaft,

a stop lever in operative communication with the motor shaft and extending radially away from motor shaft, wherein rotational motion of the motor shaft is transformed into linear translational movement of the stop lever, the stop lever moveable from a position of disengagement wherein the stop lever is out of engagement with the radial catches, to a position of engagement wherein the stop lever is in engagement with one of the radial catches.