Patent Publication Number: US-9427853-B1

Title: Apparatus and method to torque fittings

Description:
BACKGROUND 
     The subject matter described herein relates to manufacturing techniques and more particularly to apparatus and methods to torque fittings. 
     Various manufacturing operations require fittings on opposing sides of a structure to be secured to a torque threshold. By way of example, some bulkhead fittings in vehicles, such as aircraft and watercraft, include a sleeve which passes through a hole in the bulkhead. One end of the fitting includes a fixed head, while the other end of the fitting is threaded to accept a nut. Existing methods of securing the fitting require two mechanics, one on each side of the bulkhead, to torque the fitting to a torque threshold. In some circumstances the work environment is cramped, which renders the task difficult and time consuming. 
     SUMMARY 
     Accordingly, apparatus and methods to torque fittings may find utility. 
     In one example, an apparatus to apply a predetermined torque to a fitting having a head and a nut, threadably engageable with the head, is disclosed. The apparatus includes a driveshaft, configured to be arranged concentrically with an axis and to be rotatable about the axis, a first socket, configured to be arranged concentrically with the axis and to receive the head, and a second socket, configured to receive the nut and to be rotatable relative to the first socket by the driveshaft. 
     In another example, a method to apply a predetermined torque to a preinstalled fitting having a head and a nut, threadably engageable with the head, is provided. The method includes rotatably coupling a first socket to a driveshaft, inserting the driveshaft through the head and the nut, engaging the first socket with the head, coupling a second socket to the driveshaft without relative rotational motion therebetween. engaging the second socket with the nut, and rotating the driveshaft and the second socket in a direction opposite to that the fitting is threaded, while preventing rotation of the first socket. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Examples of methods and systems in accordance with the teachings of the present disclosure are described in detail below with reference to the following drawings. 
         FIG. 1  is a flow diagram of aircraft production and service methodology. 
         FIG. 2  is a block diagram of an aircraft. 
         FIGS. 3A-3B  are schematic illustrations of an illustrative fitting, according to an aspect of the disclosure. 
         FIGS. 4A-4I  are a schematic illustrations of an apparatus to torque fittings according to one or more aspects of the disclosure. 
         FIG. 5  is a flowchart illustrating operations in a method to torque fittings according to one or more aspects of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Apparatus and methods to torque fittings are described herein. In some examples, apparatus and methods described herein may be used in the manufacture of vehicles such as aircraft, ships, automobiles, or any other structures in which fittings may be installed on opposing sides of a structural member. By way of example, aircraft structures commonly include one or more bulkheads formed from metal or composite materials. During the manufacturing process, one or more fittings may be installed in a bulkhead, for example, to allow fuel lines, conduit, or the like to pass through the bulkhead. Apparatus and methods described herein facilitate the installation of such fittings. 
     Referring more particularly to the drawings, aspects of the disclosure may be described in the context of an aircraft manufacturing and service method  100  as shown in  FIG. 1  and an aircraft  102  as shown in  FIG. 2 . During pre-production, an illustrative method  100  may include specification and design  104  of the aircraft  102  and material procurement  106 . During production, component and subassembly manufacturing  108  and system integration  110  of the aircraft  102  takes place. Thereafter, the aircraft  102  may go through certification and delivery  112  in order to be placed in service  114 . While in service by a customer, the aircraft  102  is scheduled for routine maintenance and service  116  (which may also include modification, reconfiguration, refurbishment, and so on). 
     Each of the processes of method  100  may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of venders, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on. 
     As shown in  FIG. 2 , the aircraft  102  produced by the illustrative method  100  may include an airframe  118  with a plurality of systems  120  and an interior  122 . Examples of high-level systems  120  include one or more of a propulsion system  124 , an electrical system  126 , a hydraulic system  128 , and an environmental system  130 . Any number of other systems may be included. Although an aerospace example is shown, the principles of the disclosure may be applied to other industries, such as the automotive industry. 
     Apparatus and methods embodied herein may be employed during any one or more of the stages of the production and service method  100 . For example, components or subassemblies corresponding to production process  108  may be fabricated or manufactured in a manner similar to components or subassemblies produced while the aircraft  102  is in service. Also, one or more apparatus examples, method examples, or a combination thereof may be utilized during the production stages  108  and  110 , for example, by substantially expediting assembly of or reducing the cost of an aircraft  102 . Similarly, one or more of apparatus examples, method examples, or a combination thereof may be utilized while the aircraft  102  is in service, for example and without limitation, to maintenance and service  116 . 
     As described above, during the manufacturing process, one or more fittings may be installed in a bulkhead, for example, to allow fuel lines, conduit, or the like to pass through the bulkhead.  FIGS. 3A-3B  are schematic illustrations of an illustrative fitting, according to one or more aspects of the disclosure. Referring to  FIGS. 3A-3B , in some examples, a fitting  310  includes a head  312  and a nut  314  which may be threadably engagable with the head  312 . In the examples depicted in  FIGS. 3A-3B , the head  312  and the nut  314  each have a hexagonal or an otherwise-shaped surface defined such that both the head and the nut may be engaged by a suitable installation/removal tool, e.g., a socket or a wrench. Conduits, pipes, or the like may be secured to the fitting  310 . The fitting  310  defines an inner diameter  316 , through which fluids, wires, or other materials may pass. The specific dimensions of the fitting  310  are not critical. In various examples described herein, an apparatus to torque fittings, such as the fitting  310 , may be embodied as a tool which may be coupled to a driving device. In brief, the tool may include a driveshaft, attached to the driving device. The driveshaft is rotatable about an axis and is adapted to extend through the fitting. A first socket may be mounted about the driveshaft to receive the head of the fitting. The driveshaft may be extended through the fitting and a second socket may be mounted about the driveshaft to receive the nut of the fitting. Rotating the driveshaft introduces relative rotational motion between the head and the nut to torque the fitting. 
       FIGS. 4A-4I  are schematic illustrations of an apparatus for torquing fittings, according to one or more aspects of the disclosure. Referring to  FIGS. 4A-4H , in some examples, an apparatus  400  to apply a predetermine torque to a fitting, such as the fitting  310  ( FIG. 3A ), having the head  312  and the nut  314 , threadably engageable with the head  312 , is disclosed. The apparatus  400  includes a driveshaft  420 , configured to be arranged concentrically with an axis  402  and to be rotatable about the axis  402 , a first socket  430  (e.g.,  FIG. 4B ), configured to be arranged concentrically with the axis  402  and to receive the head  312  ( FIG. 4C ) of the fitting, and a second socket  440  (e.g.,  FIG. 4D ) configured to receive the nut  314  (e.g.,  FIG. 4C ) of the fitting and to be rotatable relative to the first socket  430  by the driveshaft  420 . 
     The driveshaft  420  is configured to extend through the fitting  310 , which may be fitted with a protective sleeve  304  ( FIG. 3B ) to prevent the driveshaft  420  from damaging the inner diameter  316  of the fitting  310 . 
     As illustrated, for example, in  FIG. 4A , in one aspect of the disclosure, the driveshaft  420  includes a first surface  422 , configured to engage the second socket  440  when the second socket  440  is slid onto the driveshaft. In some examples, the first surface  422  includes flat surfaces  422 , which extend along the axis  402  and engage with an aperture in the second socket  440 , such that second socket  440  may be slid onto the driveshaft  420  and such that rotating the driveshaft  420  also rotates the second socket  440 . In the example depicted in  FIGS. 4A-4G , the driveshaft  420  includes four flat surfaces  422 , such that the section of the driveshaft  420  including the flat surfaces  422  presents, e.g., a substantially square cross-section when viewed perpendicular to axis  402 . However, the particular number of flat surfaces is not critical. 
     Driveshaft  420  further includes one or more curved surfaces  424 , configured to threadably engage a retaining nut  445  ( FIGS. 4E, 4F ). In some examples, the curved surface(s)  424  also extend along the axis  402  adjacent the first surface(s)  422  to define a partial cylindrical profile. The curved surface may be threaded to receive a retaining nut  445 , which is threadably engagable with the driveshaft  420 . 
     In some examples, the driveshaft  420  may be coupled to a planetary gear drive  450 , illustrated in  FIG. 4I . The planetary gear drive  450  may include a sun gear  452 , configured to be arranged concentrically with and to be rotatable about the axis  402 , a planetary carrier  454 , configured to be coupled to the driveshaft  420  without relative rotational motion therebetween, pinion gears  455 , rotatably coupled to the planetary carrier  454  and in mesh with the sun gear  452 , a ring gear  456  in mesh with the pinion gears  455 , and a mechanical interface  458  ( FIG. 4A ) fixed to the ring gear  456 . By way of example, the planetary gear drive  450  may multiply an input torque provided by a drive device. 
     As best illustrated in  FIGS. 4A-4B , the first socket  430  is configured to be coupled to the mechanical interface  458  of the planetary gear drive  450 . The apparatus may include a retaining mechanism  460 , configured to releasably couple the first socket  430  to the mechanical interface  458 . In the example depicted in  FIGS. 4A-4G , the retaining mechanism  460  includes a spring-loaded quick-release latch  462 , which secures the first socket  430  to the mechanical interface  458  of the planetary gear drive  450 . 
     In some examples, the apparatus  400  may include means for selectively preventing rotation of the first socket  430  when the driveshaft  420  is rotated. By way of example, a breaker bar  475  ( FIG. 4G ) may be coupled to the first socket  430 , such than an operator of the apparatus can prevent initial rotation of the ring gear  456 , to which the mechanical interface  458  and the first socket  430  are coupled. In alternate examples of the means for selectively preventing rotation of the first socket  430 , a clamp or other mechanism, coupled to the first socket  430 , may be used to prevent initial rotation of the ring gear  456 . 
     As illustrated in  FIG. 4H , a rotary drive device  470  may be coupled to the sun gear  452  to drive the planetary gear drive  450 . The rotary drive device  470  is configured to operatively limit the torque input to the sun gear automatically when the predetermined torque is applied to the fitting  310 , e.g., by a clutch or other suitable mechanism. The rotary drive device  470  may be configured to rotate in a direction opposite to that the fitting  310  is threaded. 
     Having described structural components of an apparatus to torque fittings, aspects of methods to torque fittings will now be described with reference to  FIG. 5 . In use, the protective sleeve  304  may be positioned into the inner diameter of a fitting, e.g., the fitting  310 , as illustrated in  FIG. 3B . A first socket  430  may be mounted about the driveshaft  420  (operation  510 ) and secured to the mechanical interface  458  of the planetary gear drive  450  by causing the latch  462  of the retaining mechanism  460  to lock the first socket  430  to the interface  458 , as illustrated in  FIG. 4B . The driveshaft  420  may then be inserted through the inner diameter  316  of the fitting  310  (operation  515 ) and the first socket  430  may engage the head  312  of the fitting  310  (operation  520 ). 
     The second socket  440  may be coupled (operation  525 ) to the driveshaft  420 , e.g., by inserting the driveshaft  420  through a corresponding opening in the socket  440 , such that the flat surfaces  422  of the driveshaft mate with the complementary-shaped socket opening, coupling the second socket to the driveshaft without relative rotational motion therebetween. As a result, the nut  314  may be positioned in the second socket  440  (operation  530 ). At operation  535 , the driveshaft  420  is rotated. In some examples, a drive device  470  may be coupled to the planetary gear drive  450  to rotate the driveshaft  420 . Rotation of the driveshaft  420  introduces relative rotational motion between the head  312  and the nut  314 , such that the fitting  310  may be tightened or loosened depending upon the direction of relative rotational motion and the threading of the fitting. In conventional practice, to tighten the fitting, the driveshaft  420  will rotate counterclockwise when viewed from the perspective of the drive device  470 . When viewed from the opposite perspective, the nut  314  is being rotated clockwise, thereby tightening the nut  314  onto the head  312 . Conversely, to loosen the fitting, the driveshaft  420  will rotate clockwise when viewed from the perspective of the drive device  470 . When viewed from the opposite perspective, the nut  314  is being rotated counterclockwise, thereby loosening the nut  314  from the head  312 . This description assumes that the fitting has right-hand threads. The opposite would be true if the fitting had left-hand threads. The drive device  470  may be reversible to effect both tightening and loosening of the fitting  310 . 
     The planetary carrier  454  and, therefore, the driveshaft  420  and the second socket  440  will rotate in the direction of a torque applied to the sun gear  452  by the drive device  470  if the first socket  430 , connected to the ring gear  456  via a mechanical interface  458 , experiences resistance to its initial rotation, e.g., by using the breaker bar  475 . Once the first socket  430  frictionally engages the bulkhead as the fitting  310  gets tighter, the socket  430  and, therefore the ring gear  456 , remain stationary and the use of the breaker bar  475  is no longer required, since the torque circuit becomes a closed loop, thereby containing the reaction forces of the ring gear  456  within the fitting  310 . If desired, the planetary gear drive  450  may be so constructed that the torque applied by the drive device  470  to the sun gear  452  is multiplied as it is transmitted by the shaft  420  to the nut  314  via the second socket  440 . 
     Thus, the apparatus described herein provides a tool which enables fittings  310  to be torqued to a predetermined torque level using a single drive assembly that may be operated by a single operator. The apparatus is configured such that the moments generated by the opposing torques are contained within a closed torque loop, such that the net moment on the apparatus is approximately zero. 
     The respective components of the apparatus  400  may be formed from a suitably rigid material sufficiently strong to withstand the forces applied, e.g., a suitable metal or a high strength composite material. 
     In the foregoing discussion, specific implementations of illustrative processes have been described, however, it should be understood that in alternate implementation, certain acts need not be performed in the order described above. In alternate examples, some acts may be modified, performed in a different order, or may be omitted entirely, depending on the circumstances. 
     While various examples have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the present disclosure. The examples illustrate the various aspects of the disclosure and are not intended to limit the present disclosure. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.