Patent Publication Number: US-2022213876-A1

Title: Shape memory alloy based actuator latch

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a non-provisional application based on and claims priority to U.S. Provisional Application Ser. No. 63/134,480 entitled “SHAPE MEMORY ALLOY BASED ACTUATOR LATCH” filed on Jan. 6, 2021, which is incorporated herein by reference in its entirety. 
    
    
     SUMMARY 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other features, details, utilities, and advantages of the claimed subject matter will be apparent from the following, more particular written Detailed Description of various implementations as further illustrated in the accompanying drawings and defined in the appended claims. 
     A device disclosed herein includes an upper shape memory alloy (SMA) wire, a lower SMA wire, a flexure having an opening, and a spring configured within the flexure opening, wherein the lower SMA wire, and the flexure are attached at one end to an anchor and at another end to a pin. 
     An actuator latch disclosed herein includes a flexure configured between an upper shape memory alloy (SMA) wire and a lower SMA wire, wherein each of the upper SMA wire and the lower SMA wire are attached at one end to an anchor and at another end to a pin wherein the flexure has an opening configured to house a spring. 
     These and various other features and advantages will be apparent from a reading of the following Detailed Description. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
       A further understanding of the nature and advantages of the present technology may be realized by reference to the figures, which are described in the remaining portion of the specification. In the figures, like reference numerals are used throughout several figures to refer to similar components. In some instances, a reference numeral may have an associated sub-label consisting of a lower-case letter to denote one of multiple similar components. When reference is made to a reference numeral without specification of a sub-label, the reference is intended to refer to all such multiple similar components. 
         FIG. 1  illustrates an example diagram of an actuator latch configured from shape memory alloy. 
         FIG. 2  illustrates an example diagram of an actuator latch in an up position. 
         FIG. 3  illustrates an example diagram of an actuator latch in a lower position. 
         FIGS. 4A and 4B  illustrate example diagrams of an actuator latch locking an actuator. 
         FIGS. 5A and 5B  illustrate alternative example diagrams of an actuator latch in various intermediate stages of spring flexure. 
         FIG. 6  illustrates an example computing system that may implement the technology described herein. 
     
    
    
     DETAILED DESCRIPTION 
     Currently most hard drive actuators are latched in their off-disk position by a magnetic bias pin. But new types of actuator drives may not allow such a configuration, or they may need more force than a magnetic bias pin can produce. There is a need for a low cost, clean mechanical latch for future actuators. 
     One or more implementations of actuator latches disclosed herein use materials and flexure that switches between multiple stable positions. For example, in a specific implementation, the actuator latch is configured using a bistable material that allows the flexure to switch between two positions. One or more implementations of such flexures for the actuators may be made from shape memory alloys (SMAs). 
     Example of such SMAs include, nickel-titanium (Ni—Ti), Copper-Aluminum-Nickel, etc. Other SMAs that have the capability to remember their shape and are able to return to their shape even after being bent may be used. Specific SMAs that can be used to implement the flexures disclosed herein may be plastically deformed at low temperature and recover the plastic strain by increasing their temperature. 
       FIG. 1  illustrates an example diagram of an actuator latch  100  configured from shape memory alloy. As illustrated in  FIG. 1 , the actuator latch  100  is configured between an a stop or a pin  102  and an anchor  112 . The pin  102  may be attached to an actuator (not shown). The actuator latch includes a spring  104 , an upper SMA wire  106 , a lower SMA wire  108 , and a flexure  110 . The flexure  110  may have an opening wherein the spring  104  is located. The spring  104  may be made of stainless steel. The stop or pin  102  may be made of rubber or other material that has similar viscoelastic, damping and other properties conducive with operations (in a drive). The flexure  110  may also be made of a bistable or SMA material such as Ni—Ti alloy. An Ni—Ti alloy (also known as Nitinol) is an alloy with a near-equiatomic composition (i.e., 49%-51%) of nickel and titanium. Ni—Ti belongs to the class of shape memory alloys that can be deformed at a low temperature and are able to recover their original, permanent shape when exposed to a high temperature. 
     The actuator latch  100  may be designed to pre-load the actuator. 
       FIG. 2  illustrates an example side view of an actuator latch  200  in an up position. Actuator latch  200  includes pin  202 , a spring  204 , an upper SMA wire  206 , a lower SMA wire  208 , a flexure  210 , and an anchor  212 . One or more of the components  202 - 212  are substantially similar to the components  102 - 112  disclosed in  FIG. 1 . 
       FIG. 3  illustrates an example side view of an actuator latch  300  in a down position. Actuator latch  300  includes pin  302 , a spring  304 , an upper SMA wire  306 , a lower SMA wire  308 , a flexure  310 , and an anchor  312 . One or more of the components  302 - 312  are substantially similar to the components  102 - 112  disclosed in  FIG. 1  and the components  202 - 212  disclosed in  FIG. 2 . Specifically,  FIG. 3  illustrates the lower SMA wire  308  to be flexed such that in this position its length is lower than the length of the lower SMA wire  208  as shown in  FIG. 2 . Similarly, the upper SMA wire  306  to be relaxed such that in this position its length is higher than the length of the lower SMA wire  206  as shown in  FIG. 2 . The effect of the flexures of the upper SMA wire  306  and the lower SMA wire  308  results in the pin  302  being moved from its position as illustrated by  208 . 
     The upper SMA wire  306  and the lower SMA wire  308  may be flexed as necessary by changing their temperature. In one implementation, the temperatures may be changed by application of electrical current to one or both of the upper SMA wire  306  and the lower SMA wire  308 . 
       FIGS. 4A and 4B  illustrate example diagrams of an actuator latch  400  ( 400 A) locking an actuator  414 . Actuator latch  400  includes a pin  402 , a spring  404 , an upper SMA wire  406 , a lower SMA wire  408 , a flexure  410 , and an anchor  412 . Specifically, the actuator latch  400  is in a position where it blocks the actuator  414  whereas at  400 A, the actuator latch is retracted, allowing the actuator  414  to move. The actuator latch  400  may be moved to actuator latch  400 A by flexing the upper SMA wire  406  and the lower SMA wire  408  by changing their temperature. In one implementation, the temperatures may be changed by application of electrical current to one or both of the upper SMA wire  406  and the lower SMA wire  408 . 
       FIGS. 5A and 5B  illustrate alternative example diagrams of an actuator latch  500  ( 500 A) in various intermediate stages of spring flexure. Actuator latch  500  includes a pin  502 , a spring  504 , an upper SMA wire  506 , a lower SMA wire  508 , a flexure  510 , and an anchor  512 . One or more components  502 - 514  are substantially similar to the components  402 - 414  illustrated in  FIG. 4 . Specifically,  FIGS. 5A and 5B  illustrate that different combinations of flexures can be combined to form a multi-stable system that can be stable at a number of different positions and/or angles. In the illustrated implementation, the anchor  512  is attached at one end to an upper SMA wire  506   a  and to a lower SMA wire  508   a  at the other end. Furthermore, a lower end of the anchor  512  may also be attached to a spring flexure  504   a.    
     Specifically, in  FIG. 5A , the actuator latch  500  is in an up position with the pin  502  attached to an actuator  514 . In this position, the spring flexure  504   a  is extended up towards the actuator  514 . On the other hand,  FIG. 5B  illustrates the actuator latch  500 A in a down position where the pin  502  is detached from the actuator  514 . In this position, the spring flexure  504   a  is extended down and away from the actuator  514 . 
     The actuator latch  500  may be moved to actuator latch position  500 A by flexing the upper SMA wire  506  and the lower SMA wire  508  by changing their temperature. In one implementation, the temperatures may be changed by application of electrical current to one or both of the upper SMA wire  506  and the lower SMA wire  508 . 
       FIG. 6  illustrates an example processing system  600  that may be useful in implementing the described technology. The processing system  600  is capable of executing a computer program product embodied in a tangible computer-readable storage medium to execute a computer process. Data and program files may be input to the processing system  600 , which reads the files and executes the programs therein using one or more processors (e.g., CPUs, GPUs, ASICs). Some of the elements of a processing system  600  are shown in  FIG. 6  wherein a processor  602  is shown having an input/output (I/O) section  604 , a Central Processing Unit (CPU)  606 , and a memory section  608 . There may be one or more processors  602 , such that the processor  602  of the processing system  600  comprises a single central-processing unit  606 , or a plurality of processing units. The processors may be single core or multi-core processors. The processing system  600  may be a conventional computer, a distributed computer, or any other type of computer. The described technology is optionally implemented in software loaded in memory  608 , a storage unit  612 , and/or communicated via a wired or wireless network link  614  on a carrier signal (e.g., Ethernet, 3G wireless, 5G wireless, LTE (Long Term Evolution)) thereby transforming the processing system  600  in  FIG. 6  to a special purpose machine for implementing the described operations. The processing system  600  may be an application specific processing system configured for supporting the disc drive throughput balancing system disclosed herein. 
     The I/O section  604  may be connected to one or more user-interface devices (e.g., a keyboard, a touch-screen display unit  618 , etc.) or a storage unit  612 . Computer program products containing mechanisms to effectuate the systems and methods in accordance with the described technology may reside in the memory section  608  or on the storage unit  612  of such a system  600 . 
     A communication interface  624  is capable of connecting the processing system  600  to an enterprise network via the network link  614 , through which the computer system can receive instructions and data embodied in a carrier wave. When used in a local area networking (LAN) environment, the processing system  600  is connected (by wired connection or wirelessly) to a local network through the communication interface  624 , which is one type of communications device. When used in a wide-area-networking (WAN) environment, the processing system  600  typically includes a modem, a network adapter, or any other type of communications device for establishing communications over the wide area network. In a networked environment, program modules depicted relative to the processing system  600  or portions thereof, may be stored in a remote memory storage device. It is appreciated that the network connections shown are examples of communications devices for and other means of establishing a communications link between the computers may be used. 
     In an example implementation, a storage controller, and other modules may be embodied by instructions stored in memory  608  and/or the storage unit  612  and executed by the processor  602 . Further, the storage controller may be configured to assist in supporting the RAID0 implementation. A RAID storage may be implemented using a general-purpose computer and specialized software (such as a server executing service software), a special purpose computing system and specialized software (such as a mobile device or network appliance executing service software), or other computing configurations. In addition, keys, device information, identification, configurations, etc. may be stored in the memory  608  and/or the storage unit  612  and executed by the processor  602 . 
     The processing system  600  may be implemented in a device, such as a user device, storage device, IoT device, a desktop, laptop, computing device. The processing system  600  may be a storage device that executes in a user device or external to a user device. 
     The above specification, examples, and data provide a complete description of the structure and use of example embodiments of the disclosed technology. Since many embodiments of the disclosed technology can be made without departing from the spirit and scope of the disclosed technology, the disclosed technology resides in the claims hereinafter appended. Furthermore, structural features of the different embodiments may be combined in yet another embodiment without departing from the recited claims.