Patent Publication Number: US-6659399-B1

Title: Compact linear split sleeves for accurate rigging in confined space

Description:
TECHNICAL FIELD 
     The present invention relates generally to an aircraft actuator control assembly and more specifically to an aircraft actuator control rod assembly with linear split sleeves for accurate rigging in confined space. 
     BACKGROUND OF THE INVENTION 
     Aircraft mechanical systems commonly incorporate redundancy within their designs to insure proper operation even after the failure of a single component. Numerous systems within the aircraft utilize this methodology in both design and use. One such category of system involves the control of flight control surfaces on aircraft wings. Aircraft control surfaces commonly utilize actuators and actuator control rods to transfer force from drive assemblies, such as hydraulic drives, to the control surface. Many of these surfaces utilize multiple actuators so that if a single actuator fails, the redundant actuators can maintain control of the surface. 
     Although relatively simplistic in methodology, the application of such multiple actuators can present practical problems during operation if not properly designed and maintained. Improperly aligned or adjusted actuators can result in the actuators force fighting each other during operation. Design requirements commonly necessitate a minimum force fight between multiple actuators operating a flight control surface. These systems commonly require precise performance of the actuation elements and precise rigging of the actuators. Mis-rigging or improper adjustment of these systems can result in inadequate system performance or structural fatigue issues. 
     Proper rigging and adjustment, however, can prove difficult for many actuator systems located throughout an aircraft. The nature of aircraft design often results in tight packaging environments with limited or poor access to the assemblies. Such is case with aircraft rudder actuators for example. Relatively small access panels or doors in combination with location on the aircraft can make proper adjustment increasingly difficult using conventional methods and assemblies. Often actuators rely on dual jam nuts to effectuate adjustment of the individual actuator assemblies. This requires two wrenches to be inserted into the access panel in order to apply the required torque to the jam nuts. Poor access situations can restrict wrench installation and turning and thereby hamper effective and accurate adjustment of the actuator assemblies. By increasing the difficulty associated with proper rigging, present systems often increase the occurrence of misaligned or misrigged assemblies. 
     It would, therefore, be highly desirable to have an actuator control assembly with improved rigging accuracy. It would further be highly desirable to have an actuator control rod assembly with adjustment features better suited for accessibility within tight packaging environments or poor access situations. 
     SUMMARY OF THE INVENTION 
     It is therefore an object to the present invention to provide an aircraft control surface actuator assembly with improved rigging features. It is further object to the present invention to provide an aircraft control surface actuator rod assembly with rigging features suited for accessibility within tight packaging and access environments. 
     In accordance with the objects of the present invention an aircraft control surface actuator assembly is provided. The assembly includes a flight control surface. A mechanical drive mechanism is in communication with the flight control surface. The mechanical drive mechanism is driven by an actuator rod assembly including a first segment having a first control mounting end mounted to the mechanical drive mechanism and a first segment adjustment end. The first segment adjustment end includes a first segment outer diameter comprising a plurality of first segment outer threads. The assembly further includes a second segment including a second segment inner diameter having a plurality of second segment inner threads and a second segment outer diameter having a plurality of second segment outer threads. The second segment inner threads engage the first segment outer threads. The second segment further includes at least one second segment split sleeve passage such that the second segment inner diameter can be reduced under a compression force. The actuator rod assembly includes a third segment including a third segment adjustment end and a third segment mounting end. The third section adjustment end includes a third segment inner diameter having a plurality of third segment inner threads engaging the second segment outer threads. The third segment adjustment end further includes at least one third segment split sleeve passage such that the third segment inner diameter can be reduced under the compression force. Wherein the second segment inner threads and the second segment outer threads are orientated such that rotational movement of the second segment moves the first segment and the third segment in opposite linear directions. The third segment includes a clamped sleeve portion comprising a clamp actuator. The clamp actuator applying the compression force to the second segment inner diameter and the third segment inner diameter to prevent rotational movement of the second segment. 
     Other objects and features of the present invention will become apparent when viewed in light of the detailed description and preferred embodiment when taken in conjunction with the attached drawings and claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an illustration of an aircraft utilizing an aircraft actuator control assembly in accordance with the present invention; 
     FIG. 2 is an illustration of an access panel housing an aircraft actuator control assembly in accordance with the present invention; 
     FIG. 3 is internal view illustration of the aircraft actuator assembly illustrated in FIG. 2; 
     FIG. 4 is detail illustration of the actuator rod assembly illustrated in FIG. 2; 
     FIG. 5 is a side view illustration of the actuator rod assembly illustrated in FIG. 4; 
     FIG. 6 is a cross-sectional illustration of the actuator rod assembly illustrated in FIG. 5, the cross-section taken along the lines  6 — 6  in the direction of the arrows; 
     FIG. 7 is a cross-sectional illustration of the actuator rod assembly illustrated in FIG. 5, the cross-section taken along the lines  7 — 7  in the direction of the arrows; and 
     FIG. 8 is a cross-sectional illustration of the actuator rod assembly illustrated in FIG. 5, the cross-section taken along the lines  8 — 8  in the direction of the arrows. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to FIG. 1, which is an illustration of an aircraft  10  utilizing an aircraft actuator control assembly  12  in accordance with the present invention. The present invention is intended for a wide variety of applications within an aircraft  10  and for implementation into a wide variety of aircraft  10  designs. The present invention is intended for use to control aircraft control surfaces  14 . Control surfaces  14  are positioned throughout an aircraft  10  and are utilized to direct airflow and modify the flight path. Although the present invention is intended for use in controlling a wide variety of aircraft control surfaces  14 , it is preferably for use with an aircraft rudder. 
     Often, aircraft  10  provide limited access to aircraft actuator control assemblies  12  with which mechanics are required to tune the system. Access such as the access door  16  illustrated in FIG. 2, can present access problems to the components of the aircraft actuator control assembly  12  for mechanics. Traditional designs can cause rigging difficulties and may result in mis-rig situations. The present invention addresses such problems through a unique design illustrated in FIG.  3 . The aircraft actuator control assembly  12  includes a mechanical drive mechanism  18  in communication with an aircraft control surface  14 . Although a wide variety of mechanical drive mechanisms  18  are known in the airline industry, a single embodiment is illustrated in FIG.  2 . The embodiment comprises a mechanical drive lever  20  that effectuates movement of the control surface  14  through rotation about a drive shaft  22 . 
     Motion is imparted to the mechanical drive mechanism  18  from a remote actuator power assembly through the use of one or more actuator rod assemblies  24  (see FIG.  2 ). Although the use of actuator rod assemblies  24  is known, prior art designs make modification and tuning of the actuator rod assemblies  24  through tight enclosures such as the access door  16  difficult. The present invention addresses this problem through the addition of a unique actuator rod assembly  24 . The actuator rod assembly  24 , as detailed in FIG. 4, includes a first segment  26  having a first control mounting end  28  attached to the mechanical drive mechanism  18 . The first control mounting end  28  may be attached in a variety of fashions. In the illustrated embodiment, it is attached utilizing a bolt passage  30  formed in the first control mounting end  28 . The first segment  26  also includes a first segment adjustment end  32  positioned opposite the first control mounting end  28 . The first segment adjustment end  32  includes a first segment outer diameter  34  comprising a plurality of first segment outer threads  36 . The first segment adjustment end  32  provides an attachment location for a second segment  38 . 
     The second segment  38  includes a second segment inner diameter  40  having a plurality of second segment inner threads  42 . It also includes a second segment outer diameter  44  having a plurality of second segment outer threads  46 . The second segment inner threads  42  engage the first segment outer threads  36  such that rotation of the second segment  38  imparts relative lateral movement between the first segment  26  and the second segment  38 . A polygonal interface  48 , preferably hexagonal for interaction with a wrench, is positioned on one end of the second segment  38  to allow the second segment  38 , also referred to as a vernier sleeve, to be easily rotated relative to the first segment  26 . The second segment  38  further includes at least one second segment split sleeve passage  50  (see FIG.  7 ). The at least one second segment split sleeve passage  50  allows the second segment inner diameter  40  to be reduced by placing the second segment  38  under a compression force. Although the second segment  38  may be operational with as little as a single second segment split sleeve passage  50  formed along its length, one preferred embodiment contemplates the use of three second segment split sleeve passages  50 . 
     The actuator rod assembly  24  further includes a third segment  52  in communication with the second segment  38 . The third segment  52  includes a third segment adjustment end  54  and a third segment mounting end  55 . The third segment mounting end  55  is mounted to and driven by any of a variety of actuator power assembles (not shown) well known in the art. One common choice for an actuator power assembly is a hydraulic motor. The third section adjustment end  54  includes a third segment inner diameter  56  having a plurality of third segment inner threads  58  engaging the second segment outer threads  46 . Although the second segment outer threads  46  can be formed in a variety of fashions, one embodiment contemplates that the second segment outer threads  46  and the second segment inner threads  42  are orientated such that rotational movement of the second segment  38  moves the first segment  26  and the third segment  52  in opposite linear directions. This allows the length of the actuator rod assembly  24  to be easily lengthened or shortened through the rotation of the second segment  38 . It is also contemplated that the differential thread pitch between the second segment outer threads  46  and the second segment inner threads  42  are designed to allow infinitesimal adjustment of the actuator rod assembly  24  to further increase the reliability of any adjustments made. 
     The third segment adjustment end  54  also includes at least one third segment split sleeve passage  60  such that the third segment inner diameter  56  can be reduced under the compression force. Although the third segment split sleeve passage  60  can be formed in the third segment adjustment end  54  in a variety of fashions, one embodiment contemplates incorporating the third segment split sleeve passage  60  into a clamped sleeve portion  62 . The claimped sleeve portion  62  can include a clamp actuator  64 . The clamp actuator can be utilized to apply a compressive force to the third segment adjustment end  54  and the second segment  38 . The compression force, in turn, is utilized to reduce the second segment inner diameter  40  and the third segment inner diameter  50  to prevent rotational movement of the second segment  38 . In this fashion the actuator rod assembly  24  can be locked down after adjustment preventing accidental or unintended alteration of the actuator rod assembly  24  length. The additional advantage of this arrangement is that the clamp actuator  64  can be easily accessed from even small access door  16  situations. Although a variety of clamp actuators  64  are contemplated by the present invention, one embodiment contemplates the use of a nut-clamp assembly  66  facing the access door  16 . The bolt portion  67  of the nut-clamp assembly  66  preferably is positioned to contact a flat engagement surface  69  of the clamped sleeve portion  62  in order to prevent rotation of the bolt portion  67  as the nut-clamp assembly  66  is tightened. This allows a socket assembly  68  (see FIG. 3) to be easily inserted through the access door  16  without hampering access to the polygonal interface  48  of the second segment  38 . 
     The third segment  52  can further include a variety of extension rod segments  70  to lengthen the actuator rod assembly  24  such that it can reach the remote actuator power assembly. The extension rod segments  70  can be attached in a variety of fashions, including rivets  73  as illustrated in FIG.  8 . The third segment  52  can further include a third segment mounting end  55  for mounting to the power assembly. A third segment bolt passage  74  is only one optional embodiment for such attachment. By reducing the dimensions of the tools necessary to pass through the access door  16  in order to adjust the aircraft actuator control assembly  12 , the present invention not only improves the ease of adjustment, but can improve the reliability of such adjustments as well. In this fashion force fight between multiple actuator rod assembles  24  can be reduced. 
     While the invention has been described in connection with one or more embodiments, it is to be understood that the specific mechanisms and techniques which have been described are merely illustrative of the principles of the invention, numerous modifications may be made to the methods and apparatus described without departing from the spirit and scope of the invention as defined by the appended claims.