Abstract:
A valve apparatus employs a shape memory alloy. In another aspect, a shape memory member acts as a lock or trigger in combination with a separate actuator or spring to move a valve. Still another aspect uses an externally mounted shape memory member to rotate a valve if an unsafe condition causes movement of the member.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a divisional application of U.S. patent application Ser. No. 13/795,176, filed on Mar. 12, 2013, which is incorporated by reference herein. 
    
    
     BACKGROUND AND SUMMARY 
     The present disclosure relates generally to a valve and more particularly to a shape memory alloy valve. 
     Linearly moveable valves are known which use shape memory alloy (“SMA”) wires to open and close the valves. It is noteworthy that such traditional valves used the SMA wires, often shaped as helically coiled springs, to directly actuate and linearly move the valves. Examples of these traditional valves are disclosed in U.S. Pat. No. 6,840,257 entitled “Proportional Valve with Shape Memory Alloy Actuator” which issued to Dario et al. on Jan. 11, 2005, and U.S. Pat. No. 5,865,418 entitled “Flow Control Valve” which issued to Nakayama et al. on Feb. 2, 1999. Both of these patents are incorporated by reference herein. 
     Another conventional valve uses coiled SMA wires for direct rotary actuation. This construction is disclosed in U.S. Pat. No. 5,396,769 entitled “Rotary Actuator” which issued to Brudnicki on Mar. 15, 1995. This patent is also incorporated by reference herein. The prior exemplary uses required both a heat-activated movement and a driving force by the same SMA wire which is not ideal. Furthermore, SMA wires are not as well suited for rotary motion as they are for linear motion. 
     In accordance with the present invention, a valve apparatus employs a shape memory alloy. In another aspect, a shape memory member acts as a lock or trigger in combination with a separate actuator or spring to move a valve. Still another aspect uses an externally mounted shape memory member to rotate a valve if an unsafe or targetted condition causes movement of the member. A method of operating a shape memory valve is also provided. 
     The present valve apparatus is advantageous over traditional valves. For example, the present valve is automatically controlled if an unsafe temperature or electrical signal-activated current moves the shape memory member. This is especially useful to prevent fuel or chemical remaining in a tube from draining onto a fire in a vehicular engine compartment or in a manufacturing plant. This is also beneficial for automatically allowing water to flow to a building sprinkler if a fire moves the shape memory member to open the valve. More reliable and consistent actuation forces and timing are achieved by separating a valve actuation mechanism from a shape memory lock or trigger. This separation also reduces part costs since a smaller quantity of the more expensive SMA is required as compared to inexpensive materials for a spring actuator. The actuation forces are also more predictable, tunable and consistent with off-the-shelf spring steel springs while not being significantly affected by environmental temperature changes as are SMA wires. Additional advantages and features of the present invention can be ascertained from the following description and claims, in addition to the appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing a preferred embodiment of a valve apparatus of the present invention; 
         FIG. 2  is an exploded perspective view showing the preferred valve apparatus; 
         FIG. 3  is a perspective view showing a valve assembly employed in the preferred valve apparatus; 
         FIG. 4  is a top elevational view showing the valve assembly employed in the preferred valve apparatus; 
         FIG. 5  is a top elevational view showing a housing employed in the preferred valve apparatus; 
         FIG. 6  is a cross-sectional view showing the preferred valve apparatus in an open operating condition; 
         FIG. 7  is a cross-sectional view showing the preferred valve apparatus in an intermediate operating condition; 
         FIG. 8  is a cross-sectional view showing the preferred valve apparatus in a closed operating condition; 
         FIG. 9  is an end elevational view showing the preferred valve apparatus in an open operating condition; 
         FIG. 10  is an end elevational view showing the preferred valve apparatus in a closed operating condition; 
         FIG. 11  is a perspective view showing an alternate embodiment of a valve apparatus; 
         FIG. 12  is a cross-sectional view showing another alternate embodiment of a valve apparatus in an open condition; and 
         FIG. 13  is a cross-sectional view showing the alternate valve apparatus of  FIG. 12  in a close condition. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1-10 , a preferred embodiment of a valve apparatus  21  includes a housing  23 , a valve  25 , a torsion spring actuator  27 , and a shape memory alloy trigger or lock  29 . Housing  23  includes an injection molded, engineering grade polymeric body  31  with a pair of quick connectors  33  on either end thereof defining a fluid-carrying and hollow passageway  35  internally therein. A hollow and cylindrical collar  37  perpendicularly upstands from body  31  such that the collar and quick connectors define a substantially inverted T-shape (as illustrated). Elongated and flexible conduits or tubes  39  externally surround spaced apart ridges  41  of quick connectors  33  so as to carry fluid from one tube  39  through passageway  35  of housing  23  and then through the other tube  39 , when valve  25  is open. A circlip, compression ring or other external fastener removeably couples and clamps each tube  39  onto the associated quick connector. 
     Torsion spring actuator  27  includes a pair of laterally projecting tails  51  and a central helically looped section  53 . Looped section  53  is concentrically mounted around an outside of collar  37  of housing. One tail  51  abuts against a side of a retension formation  55  upstanding from housing  23  and an opposite tail abuts against a tab  57  affixed to and moving with valve  25 . 
     Valve  25  has butterfly style flow controlling faces  59  with an overmolded or assembled elastomeric seal on at least side edges thereof. Faces  59  are located within passageway  35  of housing and the side edges are curved to match an inside housing shape defining passageway  35 . Furthermore, a centering pintle  60  downwardly projects from a distal end of valve faces  59  for receipt in a depression inside a bottom of passageway  35 . A generally circular-cylindrical and hollow shaft  61  upwardly extends from faces  59  and concentrically extends through collar  37  of housing  23 . An O-ring seal  62  is overmolded or assembled onto shaft  61 . A laterally enlarged cap  63  extends from shaft  61  in a somewhat cup-shaped and concentric manner to sandwich collar  37  therebetween. A pair of flexible snap fit fingers  65  project from opposite sides of cap  63  for engagement with a peripherally enlarged lip  67  at a distal end of collar  37 ; this rotatably secures valve  25  to housing  23 . Valve  25  is preferably injection molded from an engineering grade of polymeric material with an elastomeric material overmolded on faces  59  and the edges therebetween but not on pintle  60 . 
     Shape memory alloy trigger or lock  29  is a generally inverted U-shaped (as illustrated) wire defined by a pair of generally parallel legs  71 , with turned feet  73  on distal ends thereof, and an arcuate but unlooped and uncoiled middle bridging section  75  between the legs. SMA trigger  29  is preferably a nickel-titanium or copper zinc-aluminum metallic alloy. Feet  73  of SMA trigger  29  are trapped and retained within formations  55  external to housing  23 . Middle bridging section  75  is arcuately depressed to engage within surfaces defining grooves, receptacles or slots  81  of valve cap  63 , and also surfaces defining grooves, receptacles or slots  83  of housing collar  37 . Grooves  81  and  83  are laterally aligned when valve  25  is in its nominal open operating position. 
     In operation as shown in  FIGS. 6 and 7 , valve  25  is in its nominal open position where flat faces  59  are parallel to an elongated fluid flow direction through passageway  35  of housing  23 . This allows the fluid to flow therepast in a generally unobstructed manner. SMA trigger  29  locks valve  25  in the open position by engaging aligned grooves  81  and  83  (see  FIGS. 4 and 5 ) of valve shaft  63  and housing collar  37 , respectively. It is noteworthy that SMA trigger  29  is external to housing  23  for exposure to the environmental air, although a perforated cover may surround such. 
     With reference to  FIG. 7 , middle section  75  of SMA trigger  29  moves to an outwardly bulging and expanded orientation, disengaging and unlocking grooves  81  and  83 , when SMA trigger  29  is heated past a movement or flexure transition temperature. This heating can be done by conducting an electrical current through SMA trigger  29 , or through an environmental and external air temperature increase such as with a fire. If electricity is used, then SMA trigger acts as a resistor in an electrical circuit including a vehicular battery power supply, a ground, and a computer controller acting as a switch to energize the circuit based on a signal sent from an airbag deployment sensor, crash/rollover accelerometer sensor, engine temperature sensor or the like. For example, a 0.5-0.75 mm diameter SMA wire is employed for trigger  29  when a 12 volt power supply creates 4-6 amps of electricity. 
     Torsion spring actuator  27  automatically rotates the integrated and single piece cap  63 , shaft  61  and valve  29  to the closed position illustrated in  FIGS. 8 and 10 , when SMA trigger  29  releases the grooves. Thus, flat faces  59  of valve  25  are perpendicular to the elongated passageway  35 , with the edges of valve  25  sealing against an inside surface of housing  23 , thereby obstructing and blocking fluid flow through the housing. In this vehicular situation, fuel, such as gasoline, supplied by a fuel pump  91  which otherwise remains in fuel-carrying tube  39 , is stopped from emptying past valve  25 . Then when the dangerous condition ceases, a mechanic can manually rotate valve  25  back to its open position against the biasing force of spring  27  and reengage SMA trigger  29  in the grooves. 
     Referring to  FIG. 1 , another embodiment uses valve apparatus  21  in a chemical manufacturing plant. A chemical storage, refining or other processing device  91  supplies a chemical liquid or gaseous fluid through tubes  39 . Valve  25  is automatically rotated closed in a fail-safe manner by spring actuator  27  if a fire or other dangerous environmental condition exists. Valve  25  and housing  23  are preferably made from cast or machined metal and of a larger size than in the vehicular version, however, SMA trigger  29 , spring actuator  27  and valve  25  are otherwise similarly constructed and functioning to the vehicular system. 
     A further embodiment attaches a water sprinkler  91  to valve apparatus  21  for use in extinguishing fires in a building. This system is similar to the prior vehicular or manufacturing plant versions, however, the fail-safe mode opens the valve. This can be done by orienting valve shaft and housing collar grooves  81  and  83  perpendicular to those shown in  FIGS. 4 and 5 . 
     An alternate embodiment valve apparatus  121  can be observed in  FIG. 11 . This device is identical in structure and function to that shown in  FIGS. 1 and 2 , except that the end feet of an SMA trigger  129  are secured to wings  131  laterally projecting from an outside of a cap  163  integrally coupled to a shaft  161  and a valve  125 . This allows for easier modularized preassembly of SMA trigger  129  to valve  125  before it is moveably coupled to a quick connector housing  123 . 
       FIGS. 12 and 13  show another alternate embodiment valve apparatus  221 . A spherical ballcock valve  225  is located within a passageway  235  of a housing  223  with an integral shaft  261  extending therethrough. A circular-cylindrical fluid flow through-bore  263  extends through valve  225  for concentric alignment within housing passageway  235  when valve  225  is in its open position. A lateral groove  281  is in a top of shaft  261  to operably receive an SMA trigger  229  in its nominal and open condition (see  FIG. 12 ). A torsion spring  227  is likewise provided with this embodiment as in the prior ones described hereinabove. 
     Various embodiments have been disclosed herein, but it should be appreciated that other variations may be made. For example, a leaf or tension spring can replace the torsion spring actuator although certain benefits will not be realized. Moreover, different housing shapes and constructions may be employed but various advantageous will not be achieved. Furthermore, it is envisioned that shape memory members of different shapes and materials (such as shape memory polymers) may engage/disengage these or other abutment surfaces and receptacles, however, certain benefits may be forfeited. It should also be appreciated that the present valve apparatus may be inverted or otherwise reoriented; thus, terms such as “top,” “bottom,” “upper,” “lower,” “upward,” “downward” and the like should not be considered as limiting since they simply describe the exemplary embodiments as illustrated herein. The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.