Patent Publication Number: US-2019176990-A1

Title: Shape memory alloy lumbar support system

Description:
FOREIGN PRIORITY 
     This application claims priority to Indian Patent Application No. 201711044187 filed Aug. 12, 2017, the entire contents of which is incorporated herein by reference. 
     BACKGROUND 
     Exemplary embodiments pertain to the art of aircraft seating and more specifically to a shape memory alloy lumbar support system for an aircraft seat. 
     Aircraft seats are designed to support the posture of a user by supporting, among other things, the lumbar region of the lower back. Current systems for lumbar support in aircraft seating often have multiple parts including rack and pinion mechanisms to achieve buckling of the lumbar basket there by resulting in different profiles of the lumbar support. Conventional lumbar supports can include actuation knobs or levers, cable to translate tension or compression from the actuation mechanism to the lumbar basket, and other parts in support of these components. All these components contribute to the increased weight of the seat. Components that are lightweight as required in an aircraft can be costly to manufacture and maintain over the life of the aircraft. Moreover, manually-actuated lumbar support systems do not include controls that automatically adjust to user preferences with the push of a button. 
     BRIEF DESCRIPTION 
     Disclosed is a lumbar support system for an aircraft seat. The lumbar support system includes a deformable lumbar support basket having a proximate end and a distal end. The system includes a shape memory alloy tension cable in communication with the proximate end of the deformable lumbar support basket, and in communication with the distal end of the deformable lumbar support basket. The shape memory alloy tension cable has a changeable tension length when an electric current is transmitted through the cable. The system includes a controller operatively connected with the shape memory alloy tension cable. The controller transmits the electric current through the shape memory alloy tension cable. The electric current causes the shape memory alloy tension cable to deform the lumbar support basket by tension force applied to the proximate end of the deformable lumbar support basket and the distal end of the deformable lumbar support basket. 
     A controller for a lumbar support system is also disclosed. The controller includes a non-transitory computer-readable memory storing program instructions that, when executed by a processor, cause the processor to receive an actuation signal, and determine, via the actuation signal, a user profile indicative of a magnitude of electric current to deform a deformable lumbar support basket. The processor transmits, based on the user profile, an electric current through a shape memory alloy tension cable that has a changeable tension length with the electric current through the cable. The shape memory alloy tension cable is in communication with a proximate end of the deformable lumbar support basket, and in communication with a distal end of the deformable lumbar support basket, where the electric current transmitted through the shape memory alloy causes the shape memory alloy tension cable to deform the lumbar support basket by tension force applied by the shape memory alloy tension cable to the proximate end of the deformable lumbar support basket and the distal end of the deformable lumbar support basket. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIG. 1  is a shape memory lumbar support system according to embodiments; 
         FIG. 2  is a configuration of a shape memory tension cable and deformable lumbar support basket for the lumbar support system of  FIG. 1  according to an embodiment; 
         FIG. 3  is another configuration of a shape memory tension cable and deformable lumbar support basket for the lumbar support system of  FIG. 1  according to an embodiment; 
         FIG. 4  is another configuration of a shape memory tension cable and deformable lumbar support basket for the lumbar support system of  FIG. 1  according to an embodiment; 
         FIG. 5  is another configuration of a shape memory tension cable and deformable lumbar support basket for the lumbar support system of  FIG. 1  according to an embodiment; 
         FIG. 6  is an aircraft seat configured with the lumbar support system of  FIG. 1  according to an embodiment; and 
         FIG. 7  is a controller for a lumbar support system according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
     The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” can include a range of ±8% or 5%, or 2% of a given value. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof. 
       FIG. 1  depicts a shape memory lumbar support system  100  according, to an embodiment. The lumbar support system  100  includes a controller  102  operatively connected with a switch  116  for switching a power source  118 . The system includes a deformable lumbar support basket  103  (hereafter support basket  103 ), and a shape memory alloy tension cable  112  (hereafter tension cable  112 ) in communication with the support basket  103 . The support basket  103  is described herein as having a proximate end  104  and a distal end  106 . The tension cable  112  is in mechanical communication with proximate end  104  and a distal end  106  such that when a current passes through the tension cable  112 , the tension cable  112  contracts proportionally with the magnitude of current applied through the tension cable. The tension applied to the proximal end  104  and the distal end  106  of the support basket  103  by the tension cable  112  causes the support basket  103  to deform longitudinally  114  by forcing the distal end and proximal end to come towards one another. This deformation of the support basket  103  causes the basket to bow and form an arc that supports the lumbar portion of a user&#39;s back. 
     The tension mechanism of the tension cable  112  is based on a property of the shape memory alloy from which the cable  112  is constructed. Shape memory alloy contracts when an electric current, heat, or other stimulus (depending on the material) is applied to the cable. The connecting ends  110  and  108  of the tension cable  112  include connecting means such that the current from the power source  118  can pass through the cable  112  when the switch  116  is actuated by the controller  102 . 
     The tension cable  112  is made from shape memory alloy that changes shape according to an amount of current applied to the cable. For example, the tension cable  112  may contract by a predetermined number (n) millimeters per milliamp of current. Accordingly, a predetermined response is measurable and recordable in a computer memory such that an individual setting (a magnitude of current) for achieving a desired amount of deformation of the support basket  103  is possible. For example, the controller  102  is configured to receive an actuation signal from the actuation switch  101 . The controller  102  then determines a user profile associated with the actuation signal by correlating a signal characteristic from the actuation switch to a saved user profile. The electric current has a predetermined magnitude corresponding to a tension length of the shape memory alloy tension cable  112 . The controller  102  transmits the electric current based on the user profile associated with the user identification, which is associated with a magnitude of current to transmit through the tension cable  112  that produces a corresponding amount of deformation in the basket. By deforming the basket, the system  100  can support the lumbar portion of a user&#39;s back when the system is installed on an aircraft seat. 
     The tension cable  112  is in communication with the proximate end  104  and the distal end  106  of the support basket  103  in various ways, as depicted in the various embodiments of  FIG. 2 ,  FIG. 3 ,  FIG. 4 , and  FIG. 5 . Each embodied configuration is described in greater detail below. Starting first with  FIG. 1 , the tension cable  112  is attached to the support basket by two ends of the tension cable. A first end  110  of the tension cable and a second end  108  of the tension cable  112  are depicted in  FIG. 1  as connected rigidly to the proximate end  104  and the distal end  106  in either a fixed fashion via first end of the tension cable  112 , or a second end  108  of the tension cable  112 , respectively. 
       FIG. 2  is a simplified view of the configuration of the shape memory tension cable  112  for the lumbar support system of  FIG. 1 .  FIG. 2  depicts a block diagram of the proximate end  104  and the distal end  106  of the support basket  103 . The shape memory alloy tension cable  112  includes a first connecting end  202  and a second connecting end  204 . The first and second connecting ends  202 ,  204 , are rigidly connected with the proximal and distal ends of the support basket, where the end of the tension cable  112  can apply force to the support basket  103  directly because the cable  112  is securely fastened to the basket end. Accordingly, tension force is transmitted to the basket directly through the ends without any mechanical advantage of one or more pins (as shown in  FIGS. 3-5 ). In  FIG. 2 , the first connecting end  202  rigidly connects to the proximate end  104  of the deformable lumbar support basket  103 , and the second connecting end  204  rigidly connects to the distal end  106  of the deformable lumbar support basket  103 . With the configuration of  FIG. 2 , when the controller  102  transmits the electric current from the power source  118  through the shape memory alloy tension cable  112 , the transmission causes the tension cable  112  to deform the lumbar support basket  103  with tension force received at the proximate end  104  of the deformable lumbar support basket  103  via the first connecting end  202  of the tension cable  112  and with tension force received at the distal end  106  of the deformable lumbar support basket  103  via the second connecting end  204  of the tension cable  112 . 
       FIG. 3  is another configuration of a shape memory tension cable  112  for the lumbar support system of  FIG. 1 , according to another embodiment. As shown in  FIG. 3 , the shape memory alloy tension cable  112  includes a first connecting end  206  and a second connecting end  208 . The first and second connecting ends  206 ,  208  both rigidly connect to the proximate end  104  of the deformable lumbar support basket  103 . The distal end  106  includes a pin  210  in communication with the shape memory alloy tension cable  112  such that the electric current transmitted by the controller  102  from the power source  118  through the shape memory alloy tension cable  112  causes the tension cable  112  to deform the lumbar support basket  103  with tension force received at the distal end  106  via the pin and received at the proximate end  104  via the first connecting end  206  and second connecting end  208  of the tension cable  112 . As shown in  FIG. 3 , the mechanical advantage of the tension force applied to the proximate and distal ends  104 ,  106 , of the lumbar basket  103  results in 2F (two times the force applied in the configuration of  FIG. 2  at the same given current). 
       FIG. 4  is another configuration of a shape memory tension cable  112  for the lumbar support system  100  of  FIG. 1  according to an embodiment. The configuration of  FIG. 4  depicts a first connecting end  202  of the shape memory alloy tension cable  112  rigidly connecting to the distal end  106  of the deformable lumbar support basket  103 . As shown in  FIG. 4 , a second connecting end  204  of the shape memory alloy tension cable  112  rigidly connects to the proximate end  104  of the deformable lumbar support basket  103 . A first pin  212  rigidly connects to the proximate end  104  of the support basket  103 , and is in communication with the shape memory alloy tension cable  112 , where the shape memory alloy tension cable  112  loops around the first pin  212  to provide mechanical advantage to the force applied to the distal and proximate ends. As shown in  FIG. 4 , a second pin  218  rigidly connects to the distal end  106  and is in communication with the shape memory alloy tension cable  112  by providing mechanical advantage to the tension force applied. The electric current transmitted by the controller  102  from the power source  118  through the shape memory alloy tension cable  112  causes the shape memory alloy tension cable  112  to deform the lumbar support basket  103  with tension force received at the proximate end  104  via the first pin  212  and via the second connecting end  204  of the tension cable  112 . The electric current also causes the deformation of the lumbar support basket  103  with tension force received at the distal end  106  via the first connecting end  202  of the shape memory alloy tension cable  112  and the second pin  218 . As shown in  FIG. 4 , the force applied by the shape memory alloy tension cable  112  is three times (3F) the force applied in  FIG. 2 . 
       FIG. 5  is another configuration of a shape memory tension cable for the lumbar support system of  FIG. 1 , according to an embodiment. A first connecting end  202  of the shape memory alloy tension cable  112  rigidly connects to the proximate end  104  of the deformable lumbar support basket  103 . A second connecting end  204  of the shape memory alloy tension cable  112  rigidly connects to the proximate end  104  of the deformable lumbar support basket  103 . A first pin  212  rigidly connects to the proximate end  104  and is in communication with the shape memory alloy tension cable  112 . The tension force is transmitted from the shape memory alloy tension cable  112  to the first pin  212  as the cable  112  wraps around the first pin  212  and applies force to the first pin  212  when the shape memory alloy tension cable  112  tenses. Similarly, a second pin  218  and a third pin  228  rigidly connect to the distal end  106  of the support basket  103 , and is in communication with the shape memory alloy tension cable  112  as described above with respect to the first pin  212 . The electric current transmitted by the controller  102  from the power source  118  through the shape memory alloy tension cable  112  causes the tension cable  112  to deform the lumbar support basket  103  with tension force received at the proximate end  104  via the first pin  212  and via the first connecting end  202  of the shape memory alloy tension cable  112 , the second connecting end  204  of the tension cable  112  and the first pin  212 , and with tension force received at the distal end  106  via the second pin  218  and the third pin  228 . 
       FIG. 6  is an aircraft seat configured with the lumbar support system of  FIG. 1  according to an embodiment. As shown in  FIG. 6 , the lumbar support system  100  as shown in  FIG. 1  supports the lumbar portion of a user&#39;s  602  back. 
       FIG. 7  is a controller for a lumbar support system according to an embodiment. As shown in  FIG. 7 , the controller  102  for the lumbar support system  100  includes a non-transitory computer-readable memory  702  storing program instructions that, when executed by a processor  701 , cause the processor  701  to receive an actuation signal, and determine, via the actuation signal, a user profile  710  indicative of a magnitude of electric current  708  to deform a deformable lumbar support basket (e.g., lumbar support basket  103 ). As shown in  FIG. 7 , the memory  702  includes user profile information  710  that associates a magnitude setting  708  of the current to apply to the shape memory alloy tension cable  112 . A record for each unique user  706  is saved on the memory  702 . The processor  701  transmits, based on the user profile information  710 , an electric current through a shape memory alloy tension cable  112  that has a changeable tension length with the electric current through the cable. As described with respect to  FIGS. 1-6 , the shape memory alloy tension cable  112  is in communication with a proximate end of the deformable lumbar support basket, and in communication with a distal end of the deformable lumbar support basket (which can vary according to the embodiments depicted with respect to  FIGS. 2-5 ). The electric current transmitted through the shape memory alloy tension cable  112  causes the shape memory alloy tension cable  112  to deform the lumbar support basket  103  by tension force applied by the shape memory alloy tension cable  112  to the proximate end  104  of the deformable lumbar support basket  103  and the distal end  106  of the deformable lumbar support basket  103 . 
     While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.