Abstract:
A ram air turbine actuator release device to release a ram air turbine actuator includes a lock bolt releasably engaged to the ram air turbine actuator, a toggle including a toggle roller to engage the lock bolt, and a toggle pivot to couple the toggle to the ram air turbine actuator, a toggle actuator, including an actuation source, and a stroke amplifier, including a piston coupled to the actuation source, a first hydraulic chamber having a first diameter in fluid communication with the piston, a second hydraulic chamber having a second diameter in fluid communication with the first hydraulic chamber, and a plunger in fluid communication with the second chamber, wherein a diameter ratio between the first hydraulic chamber and the second hydraulic chamber amplifies a displacement of the actuation source to displace the plunger to rotate the toggle to disengage the toggle roller from the lock bolt.

Description:
BACKGROUND 
       [0001]    The subject matter disclosed herein relates to release mechanisms, and more particularly, to release mechanisms for ram air turbines. 
         [0002]    Ram Air Turbines (RATs) are utilized on numerous aircraft to provide hydraulic and electrical power in emergency situations. The RAT is stowed in the aircraft structure and deployed into the air stream by a deployment actuator. A release mechanism is utilized to release the deployment actuator as required. Often, the release mechanism may add additional weight to an aircraft and require adjustment to provide sufficient displacement and force for reliable operation. 
       BRIEF SUMMARY 
       [0003]    According to an embodiment, a ram air turbine actuator release device to release a ram air turbine actuator includes a lock bolt releasably engaged to the ram air turbine actuator, a toggle including a toggle roller to engage the lock bolt, and a toggle pivot to couple the toggle to the ram air turbine actuator, a toggle actuator, including an actuation source, and a stroke amplifier, including a piston coupled to the actuation source, a first hydraulic chamber having a first diameter in fluid communication with the piston, a second hydraulic chamber having a second diameter in fluid communication with the first hydraulic chamber, and a plunger in fluid communication with the second chamber, wherein a diameter ratio between the first hydraulic chamber and the second hydraulic chamber amplifies a displacement of the actuation source to displace the plunger to rotate the toggle to disengage the toggle roller from the lock bolt. 
         [0004]    According to an embodiment, a ram air turbine system includes a ram air turbine, a deployment actuator to deploy the ram air turbine, and a ram air turbine actuator release device to release the deployment actuator, the ram air turbine actuator release device including a lock bolt releasably engaged to the deployment actuator, a toggle including a toggle roller to engage the lock bolt, and a toggle pivot to couple the toggle to the deployment actuator, a toggle actuator, including an actuation source, and a stroke amplifier, including a piston coupled to the actuation source, a first hydraulic chamber having a first diameter in fluid communication with the piston, a second hydraulic chamber having a second diameter in fluid communication with the first hydraulic chamber, and a plunger in fluid communication with the second chamber, wherein a diameter ratio between the first hydraulic chamber and the second hydraulic chamber amplifies a displacement of the actuation source to displace the plunger to rotate the toggle to disengage the toggle roller from the lock bolt. 
         [0005]    Technical function of the embodiments described above includes a stroke amplifier, including a piston coupled to the actuation source, a first hydraulic chamber having a first diameter in fluid communication with the piston, a second hydraulic chamber having a second diameter in fluid communication with the first hydraulic chamber, and a plunger in fluid communication with the second chamber, wherein a diameter ratio between the first hydraulic chamber and the second hydraulic chamber amplifies a displacement of the actuation source to displace the plunger to rotate the toggle to disengage the toggle roller from the lock bolt. 
         [0006]    Other aspects, features, and techniques of the embodiments will become more apparent from the following description taken in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The subject matter is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the embodiments are apparent from the following detailed description taken in conjunction with the accompanying drawings in which like elements are numbered alike in the FIGURES: 
           [0008]      FIG. 1  is an isometric view of one embodiment of a ram air turbine; 
           [0009]      FIG. 2  is an isometric view of one embodiment of a deployment actuator for use with the ram air turbine of  FIG. 1 ; 
           [0010]      FIG. 3  is a cross sectional view of the deployment actuator of  FIGS. 2 ; and 
           [0011]      FIG. 4  is a schematic view of one embodiment of a release mechanism for use with the deployment actuator of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Referring to the drawings,  FIG. 1  shows a ram air turbine (RAT) system  10 . In the illustrated embodiment, the RAT system  10  includes a housing  14 , a strut  16 , a turbine  18  and a deployment actuator  24 . In the illustrated embodiment, the turbine  18  can be deployed into the airstream to generate electricity or pressurize hydraulic fluid for use within the aircraft during emergency events. 
         [0013]    In the illustrated embodiment, the RAT system  10  is secured to an aircraft structure  12  by the housing  14 . The housing  14  pivotally supports a strut  16  having a turbine  18  at one end. The turbine  18  includes blades  20 , which impart rotational drive to at least one of a generator  22  and/or a hydraulic pump  30 . 
         [0014]    In the illustrated embodiment, the deployment actuator  24  is secured to the strut  16  at a first end  26  and to the housing  14  at a second end  28 . In the illustrated embodiment, the deployment actuator  24  is stowed in a compressed position to allow the deployment actuator  24  to release the strut  16  and the turbine  18  when the deployment actuator  24  is released. In  FIG. 1  the actuator  24  is illustrated in its deployed position. 
         [0015]    Referring to  FIGS. 2 and 3 , the deployment actuator  24  is shown. In the illustrated embodiment, the deployment actuator  24  has a first end  26 , a second end  28 , a housing  32 , a first cylinder  34 , a second cylinder  36 , a deployment spring  38  and a release mechanism  40 . In the illustrated embodiment, the first cylinder  34  and the second cylinder  36  are telescopically arranged relative to each other. 
         [0016]    In the illustrated embodiment, the deployment spring  38  is arranged between the first cylinder  34  and the second cylinder  36 . In  FIG. 2 , the deployment spring  38  is shown in a compressed state with the actuator  24  in its retracted position. Advantageously, the energy required to deploy the turbine  18  is stored in the deployment spring  38  when the actuator  24  is in the retracted position. 
         [0017]    In the illustrated embodiment, the release mechanism  40  is mounted near the second end  28  of the actuator  24 . In the illustrated embodiment, the release mechanism  40  can be actuated to initiate the deployment sequence within e deployment actuator  24  and release the deployment spring  38 . 
         [0018]    Referring to  FIG. 3  a simplified cross sectional view of the deployment actuator  24  is shown. In the illustrated embodiment, the deployment actuator  24  further includes a toggle  46 , a reset plunger  44 , and a lockbolt  50 . 
         [0019]    In the illustrated embodiment, the lockbolt  50  is shown in a simplified manner. In the illustrated embodiment, the lockbolt  50  within the deployment actuator  24  can actuate or otherwise manipulate the actuator locking mechanism  52 . In the illustrated embodiment, the lockbolt  50  is biased in an upward position by the lockbolt spring  54  acting upon a shoulder or collar on the lockbolt  50 . 
         [0020]    In the illustrated embodiment, the actuator locking mechanism  52  is a pawl or ratchet mechanism that selectively keeps the deployment spring  38  compressed. In certain embodiments, the actuator locking mechanism  52  is any suitable mechanism to keep the deployment spring  38  compressed. In the illustrated embodiment, the actuator locking mechanism  52  can be disengaged by the upward movement of the lockbolt  50 . After the actuator locking mechanism  52  is disengaged, the actuator locking mechanism  52  can release the deployment spring  38  to allow the deployment actuator  24  to deploy the turbine  18 . 
         [0021]    In the illustrated embodiment, the toggle  46  can prevent the upward movement of the lockbolt  50  until deployment is required. In the illustrated embodiment, the toggle  46  includes a toggle pivot  47  and a toggle roller  48 . In the illustrated embodiment, the toggle  46  is a rigid bar that is fixed to the second end  28  via a toggle pivot  47 . The toggle  46  can rotate about the toggle pivot  47 . In the illustrated embodiment, the toggle roller  48  is disposed on the opposite end of the toggle  46  and follows the upper profile of the lockbolt  50 . In a retracted position, the toggle roller  48  follows a flat surface of the lockbolt  50 . In this position the toggle  46  reacts against the upward force of the lockbolt spring  54  to retain the lockbolt  50  in a retracted position. 
         [0022]    In the illustrated embodiment, the plunger  42  can displace the toggle  46  in order to deploy the deployment actuator  24 . In certain embodiments, the plunger  42  can displace the toggle  46  approximately ⅛ th  of an inch to release the lockbolt  50 . Further, in certain embodiments, the plunger  42  can apply a constant force to the toggle  46  to overcome the force of the lockbolt spring  54 . In the illustrated embodiment, the plunger  42  is translated by the release mechanism  40 . Advantageously, the release mechanism  40  can provide sufficient displacement and force for reliable operation of the lockbolt  50  without requiring additional adjustments such as shimming. 
         [0023]    During operation, the plunger  42  pushes the toggle  46  to cause the toggle roller  48  to roll along the top of the lockbolt  50 . As the toggle roller  46  rolls along the top of the lockbolt  50 , the toggle  46  may require a constant force to overcome the bias force provided by the lockbolt spring  54 . In the illustrated embodiment, as the toggle roller  48  reaches the rounded corner of the lockbolt  50 , the toggle  46  no longer has to overcome the bias force of the lockbolt spring  54  to rotate about the toggle pivot  47 . In the illustrated embodiment, the lockbolt  50  is free to move axially after the toggle  46  is pushed beyond the lockbolt  50 . After the lockbolt  50  is disengaged by the toggle  46 , the lockbolt  50  may be urged upward by the lockbolt spring  54 . The lockbolt  50  can then release the actuator locking mechanism  52  as described. 
         [0024]    After the deployment actuator  24  has been released, the deployment actuator  24  can be retracted to prepare the deployment actuator  24  for another use. As the deployment actuator  24  is retracted, the deployment spring  38  can be compressed to re-energize the deployment actuator  24 . In the illustrated embodiment, the lockbolt  50  can be moved downward to recompress the lockbolt spring  54 . As the lockbolt spring  54  is compressed and the lockbolt  50  is moved downward, the reset plunger  44  can urge the toggle  46  back to an engaged position. The reset plunger spring  45  can push the reset plunger  44  to place the toggle  46  on the top portion of the lockbolt  50 . 
         [0025]    Referring to  FIG. 4 , the actuator release mechanism  40  is shown in greater detail. In the illustrated embodiment, the actuator release mechanism  40  includes a stroke amplifier  60  and an actuation source  70 . In the illustrated embodiment, the actuation source  70  can displace the plunger  42  via the stroke amplifier  60 . 
         [0026]    The actuation source  70  can be any suitable actuation source. In other embodiments, the actuation source  70  can be any actuator that may provide a high force and low displacement actuation. In the illustrated embodiment, the actuation source  70  is a piezoelectric actuator. Advantageously, piezoelectric actuators can provide high force when a voltage is applied, while providing reliable operation in high vibration and other harsh environments. In certain applications, the actuation source  70  may not provide sufficient displacement to disengage the toggle  46  from the lockbolt  50 . In the illustrated embodiment, the actuation source  70  can be used with a stroke amplifier  60  to provide a greater displacement when using a high force, low displacement actuation source  70 . 
         [0027]    In the illustrated embodiment, the stroke amplifier  60  can amplify the displacement of the actuation source  70  to provide a desired displacement suitable to displace the plunger  42  to trip the toggle  46 . In the illustrated embodiment, the stroke amplifier  60  includes a first chamber  62 , a piston  66 , and a second chamber  68 . 
         [0028]    In the illustrated embodiment, the actuation source  70  is coupled to the piston  66 . During operation, as the actuation source  70  is energized, the displacement of the actuation source  70  can displace the piston  66 . Accordingly, the piston  66  can displace hydraulic fluid within the first chamber  62 . In the illustrated embodiment, the first chamber  62  has a first diameter. As the piston  66  is displaced, hydraulic fluid is displaced to increase force within the second chamber  68 . In the illustrated embodiment, the second chamber  68  has a second diameter. In the illustrated embodiment, the plunger  42  can receive force and displacement from the second chamber  68 . 
         [0029]    In the illustrated embodiment, the second chamber  68  has a smaller second diameter than the first diameter of the first chamber  62 . Therefore, the ratio between the diameter of the second chamber  68  and the diameter of the first chamber  62  creates a mechanical advantage that allows the plunger in communication with the second chamber  68  to be displaced further than the displacement of the piston  66 . Accordingly, the plunger  42  is displaced further than the displacement caused by the actuation source  70 . In certain embodiments, the ratio between the first diameter of the first chamber  62  and the second diameter of the second chamber  68  can be adjusted to provide the desired displacement amplification to the plunger  42 . 
         [0030]    In the illustrated embodiment, the return spring  63  disposed within the first chamber  62  can bias the piston  66  to return to an original position after the toggle  46  has been disengaged. In certain embodiments, after the actuation source  70  is de-energized, the plunger  42  can be returned to an original position to allow for the deployment actuator  24  to be reset. 
         [0031]    In certain embodiments, a hydraulic reservoir  64  can provide fluid into the first chamber  62  to replenish fluid lost during operation. The check valve  65  can prevent fluid from flowing back into the hydraulic reservoir  64 . In certain embodiments, the stroke amplifier  60  is in fluid communication with other hydraulic components within the RAT system  10  and the aircraft generally. 
         [0032]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments. While the description of the present embodiments has been presented for purposes of illustration and description, it is not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications, variations, alterations, substitutions or equivalent arrangement not hereto described will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the embodiments. Additionally, while various embodiments have been described, it is to be understood that aspects may include only some of the described embodiments. Accordingly, the embodiments are not to be seen as limited by the foregoing description, but are only limited by the scope of the appended claims.