Shape memory alloy motor

• US 8,316,840 B2
• Filed: 08/22/2009
• Issued: 11/27/2012
• Est. Priority Date: 09/27/2005
• Status: Active Grant

• Current Assignee: Altaii Karim, Thomas Benjamin
• Original Assignee: Altaii Karim, Thomas Benjamin
• Inventors: Karim, Altaii, Benjamin, Thomas
• Primary Examiner(s): MULLINS, BURTON S
• Application Number:
  US12/583,464
• Publication Number:
  US 20090315489A1
• Time in Patent Office: 1,193 Days
• Field of Search: 310/306, 310/75.R, 310/83, 60527-529, 74/891.4, 192/48.92, 353/3, 126/518, 126605-606
• US Class Current: 126/581
• CPC Class Codes: F24S 2030/11 Driving means
• CPC Class Codes: F24S 2030/134 in the form of gearings or rack-and-pinion transmissions
• CPC Class Codes: F24S 2030/16 Hinged elements; Pin connections
• CPC Class Codes: F24S 25/70 with means for adjusting the final position or orientation of supporting elements in relation to each other or to a mounting surface; with means for compensating mounting tolerances
• CPC Class Codes: F24S 30/455 Horizontal primary axis
• CPC Class Codes: F24S 50/20 for tracking
• CPC Class Codes: G01S 3/7861 Solar tracking systems
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H02S 20/32 specially adapted for solar tracking
• CPC Class Codes: Y02E 10/47 Mountings or tracking
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y10T 74/18888 Reciprocating to or from oscillating
• CPC Class Codes: Y10T 74/19828 Worm

Abstract

The invention discloses a novel and efficient drive mechanism for use in a variety of applications. This novel mechanism replaces traditional stepper motors or another analogous art with shape memory alloys. The drive mechanism so disclosed provides substantial operational benefits over conventional motors and other such traditional drive mechanisms that would be used in similar applications. The drive mechanism includes a high gear-ratio worm gear and worm drive which further provides precise, controlled movement of an output shaft. In the illustrative use elaborated upon herein, the motor is used to drive a photovoltaic panel so that the panel may remain in appropriate alignment with the sun throughout the day.

Claims

1. A drive mechanism incorporating shape memory alloy actuators comprising:

A motor comprising at least one shape memory alloy actuator, a drive shaft and at least two unidirectional bearings operating in the same direction;

at least one spring attached to one of the at least two unidirectional bearings;

said unidirectional bearings allowing said drive shaft to travel in only one direction;

A worm gear fixed to an output shaft; and

A worm drive mounted on said drive shaft wherein said worm drive engages said worm gear to transmit the rotational force of the motor to the worm gear and therethrough to said output shaft.

2. The device as in claim 1 further comprising a means for controlling the operation of said motor.

3. The device as in claim 2 wherein said means for controlling the operation of said motor comprises an analog circuit.

4. The device as in claim 3 wherein said analog circuit includes at least one resistor and at least one capacitive device.

5. The device in claim 3 wherein said analog circuit regulates or controls at least one of the following variables of said motor:

voltage, current, duration of current flow, or number of cycles of current flow.

6. The device as in claim 3 further comprising at least one phototransistor;

said analog circuit electrically connected to said phototransistor whereby said phototransistor may transmit electrical signals to said analog circuit.

7. The device in claim 3 wherein said analog circuit includes a P-type metal oxide semiconductor field effect transistor.

8. The device as in claim 2 wherein said means for controlling the operation of said motor comprises a microprocessor.

9. A drive mechanism incorporating shape memory alloy actuators comprising:

a shape memory alloy actuator;

a first unidirectional bearing attached to one end of said shape memory alloy actuator;

at least one spring attached to said first unidirectional bearing;

a drive shaft;

a second unidirectional bearing allowing rotation of the drive shaft in only one direction;

a worm gear fixed to an output shaft; and

a worm drive mounted on said drive shaft,

whereby said worm drive engages said worm gear to transmit force to the worm gear and therethrough to said output shaft.

10. The drive mechanism of claim 9 further including a third unidirectional bearing operating on said drive shaft and allowing rotation of the drive shaft in only one direction.

11. A drive mechanism incorporating shape memory alloy actuators comprising:

a worm gear assembly,

a drive shaft engaging said worm gear assembly;

a backlash bearing comprising at least one unidirectional bearing mounted on said drive shaft;

said backlash bearing permitting said drive shaft to rotate in only one direction; and

at least one drive assembly, said drive assembly comprising at least one unidirectional bearing mounted on said drive shaft, at least one shape memory actuator engaging said at least one unidirectional bearing of said drive assembly, and at least one spring engaging said at least one unidirectional bearing of said drive assembly;

whereby contraction of said at least one shape memory actuator in said at least one drive assembly rotates said at least one unidirectional bearing in said drive assembly in a first direction and contraction of said spring rotates said at least one unidirectional bearing in said drive assembly in a second direction which results in the transmission of force to said worm gear assembly.