Abstract:
A method and apparatus for connecting air conditioning coolant lines. The apparatus comprises a coupler body, a coolant line, a flexible annular seal, a nut, and a deformable annular retainer. The coupler body has a passageway extending therethrough and a coolant line is disposed at least partially within the passageway. A flexible annular seal is disposed within the passageway in the coupler body for sealingly engaging the coolant line. The nut receives the coolant line therein and threadably engages the coupler body. A deformable annular retainer is disposed on the coolant line for engagement with the nut and the coupler body, wherein the threadable engagement of the nut with the coupler body urges the deformable annular retainer into a sealing engagement with the coupler body and the coolant line. The method includes swaging a deformable annular retainer to a coolant line, providing a nut on the coolant line, providing a coupler body having a passageway and a flexible annular seal disposed within the passageway, engaging the coolant line with the flexible annular seal to create a first seal, engaging the coupler body with the deformable annular retainer to create a second seal, and tightening a threaded engagement of the nut and the coupler body.

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of connecting air conditioning coolant lines, and more particularly, the present invention relates to a method and apparatus for connecting air conditioning coolant lines on aircraft. 
     BACKGROUND OF THE INVENTION 
     Connecting air conditioning coolant lines on aircraft poses significant difficulty. In non-aircraft applications, air conditioning coolant lines are typically fabricated from copper and aluminum, and thus, such aircraft coolant lines are commonly welded together. However, air conditioning coolant lines on aircraft cannot be welded on an aircraft due to the risk of fire or explosion. Furthermore, installation and connection of air conditioning coolant lines is difficult due to the tight spaces that are provided to such coolant lines on aircraft. 
     Typically, air-conditioning coolant lines require sealed couplings and fittings which require tightening with various tools. However, the tight spaces provided on aircraft make it difficult for the installers to tighten such couplings and fittings with their tools. Although flares or fittings are useful for similar applications, they have proven ineffective for aircraft cooling systems due to the leaking of such flares and fittings caused by small molecules provided in the coolant. 
     It would be desirable to provide an apparatus for connecting air conditioning coolant lines on an aircraft that does not require tightening through the use of tools. It would also be desirable to provide an apparatus for connecting air conditioning coolant lines on an aircraft that was not susceptible to leaking. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a method and apparatus for connecting air conditioning coolant lines on aircraft. The apparatus for connecting air conditioning coolant lines of the present invention provides a coupler body, a coolant line, a flexible annular seal, a nut, and a deformable annular retainer. 
     The coupler body has a passageway extending therethrough. A chamfered engagement surface is formed in the coupler body adjacent to the passageway for complementarily engaging the deformable annular retainer. An annular groove is formed in the coupler body adjacent to the passageway and axially inward of the chamfered engagement surface. The coolant line is disposed at least partially within the passageway in the coupler body, and the flexible annular seal is disposed within the annular groove in the coupler body for sealing engagement with the coolant line. 
     The nut has a first inner periphery portion and a second inner periphery portion, as well as a radially extending shoulder. The first inner periphery portion slidably engages the coolant line. The second inner periphery portion is radially spaced from the coolant line to define an annular recess. Additionally, the second inner periphery portion of the nut threadably engages the outer periphery of the coupler body. 
     A deformable annular retainer is disposed within the annular recess for engagement with the nut, the coolant line, and the coupler body. The deformable annular retainer has at least a first engagement surface that complementarily engages the chamfered engagement surface of the coupler body, and at least a second engagement surface that complementarily engages the radially extending shoulder of the nut. Engagement of the nut with the coupler body urges the deformable annular retainer into sealing engagement with the coupler body and the coolant line. The deformable annular retainer may have a front ferrule and a back ferrule, wherein the first engagement surface is disposed on the front ferrule, the second engagement surface is disposed on the back ferrule, and the front ferrule and the back ferrule engage one another. 
     The method for connecting air conditioning coolant lines of the present invention includes swaging a deformable annular retainer to the outer periphery of an air conditioning coolant line on an aircraft, providing a nut on the air conditioning coolant line, and providing a coupler body having a passageway extending therethrough and a flexible annular seal disposed within the passageway. The method further includes engaging the air conditioning coolant line with the flexible annular seal to create a first seal between the coupler body and the coolant line, engaging the coupler body with the deformable annular retainer to create a second seal between the coupler body and the coolant line, and tightening a threaded engagement of the nut and the coupler body to maintain engagement of the coupler body and the deformable annular retainer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The description herein makes reference to the accompanying drawings wherein like referenced numerals refer to like parts throughout several views and wherein: 
         FIG. 1  is a perspective view of the apparatus for connecting air conditioning coolant lines of the present invention; 
         FIG. 2  is a sectional view of a nut of the apparatus for connecting air conditioning coolant lines of the present invention; 
         FIG. 3  is a sectional view of a front ferrule of the apparatus for connecting air conditioning coolant lines of the present invention; 
         FIG. 4  is a sectional view of a back ferrule of the apparatus for connecting air conditioning coolant lines of the present invention; 
         FIG. 5  is a sectional view of a coupler body of the apparatus for connecting air conditioning coolant lines of the present invention; 
         FIG. 6  is a sectional view of the apparatus for connecting air conditioning coolant lines of the present invention in a disengaged position; and 
         FIG. 7  is a sectional view of the apparatus for connecting air conditioning coolant lines of the present invention in an engaged position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings, the present invention will now be described in detail with reference to the preferred embodiment. 
       FIG. 1  shows a coupling apparatus or coupler  10  for connecting air conditioning coolant lines of the present invention. Although the present invention allows for the non-welded connection of air conditioning coolant lines in restricted spaces and is thus ideally suited for use on aircraft, the present invention is not limited to aircraft coolant lines, but rather, the present invention may be utilized in any application where air conditioning coolant lines are being connected, space is restricted, and welding is prohibited. The coupler  10  includes a coupler body  70  having a flexible annular seal or o-ring  90  mounted therein for creating a first seal between the coupler body  70  and an aircraft coolant line  1 . The present invention also provides a deformable annular retainer  40  and a nut  20  that cooperate to both secure the coupler body  70  with respect to the aircraft coolant line  1  and create a second seal between the coupler body  70  and the aircraft coolant line  1 . In this manner, the o-ring  90  and the deformable annular retainer  40  provide supplementary seals in case one of them is damaged. The coupler  10  of the present invention has a disengaged position, wherein the coupler body  70  is not sealed with respect to the aircraft coolant line  1 , and an engaged position, wherein the coupler body  70  is sealed with respect to the aircraft coolant line  1  so that fluid, such as air conditioning coolant, may flow between the aircraft coolant line  1  and the coupler body  70  without leaking through the coupler  10 . 
     To carry coolant through an aircraft air conditioning system, the aircraft coolant line  1  provides a thin-walled substantially tubular member that extends along a longitudinal axis  1   a  and has a substantially smooth, round outer periphery  2 . The aircraft coolant line  1  is of a conventional design and may be fabricated from any suitable material, such as copper or aluminum. 
     In order to secure the coupler body  70  to the aircraft coolant line  1 , the nut  20  is designed to be slidably disposed around the outer periphery  2  of the aircraft coolant line  1 . Accordingly, the nut  20  is substantially tubular, having an internal passageway  26  that extends along a longitudinal axis  20   a  between a first end  22  and a second end  24  of the nut  20 , as shown in  FIG. 2 . An outer periphery  28  of the nut  20  allows for gripping or manipulation of the nut  20  either by hand or by using a tool (not shown). Accordingly, the outer periphery  28  of the nut  20  may be substantially hexagonal-shaped for engagement with a tool, such as a conventional wrench, or may be provided with other geometric or surface features to allow for enhanced engagement by a hand or by a tool. 
     The inner periphery of the nut  20  provides a first inner periphery portion  30   a  that is adjacent to the first end  22  of the nut  20  and a second inner periphery portion  30   b  that is adjacent to the second end  24  of the nut  20 . The first inner periphery portion  30   a  has an internal diameter that is relatively smaller than the internal diameter of the second inner periphery portion  30   b , and the first inner periphery portion  30   a  is separated from the second inner periphery portion  30   b  by a radially extending shoulder  32  that faces the second end  24  of the nut  20 . At least part of the second inner periphery portion  30   b  of the nut  20  has a threaded portion  34  formed thereon for engagement with the coupler body  70 , as will be explained in detail herein. 
     To secure the aircraft coolant line  1  to the coupler body  70 , the deformable annular retainer  40  is a substantially annular member fabricated from a deformable material and designed to respond to axial force by deforming radially, which causes frictional engagement of the deformable annular retainer  40  with both the aircraft coolant line  1  and the coupler body  70 . In this regard, it is important to note that the deformable annular retainer  40 , namely the front ferrule  42  and the back ferrule  54 , may slide with respect to the aircraft coolant line  1  when first assembled and prior to being swaged to the aircraft coolant line  1 . As is well known to those skilled in the art, swaging is a process by which axial force is applied to one or more ferrules, causing the ferrules to deform radially and grip an adjacent rod, tube, or sleeve. Accordingly, swaging causes the deformable annular retainer  40  to bite into the aircraft coolant line  1 , thus fixing the deformable annular retainer  40  in place with respect to the aircraft coolant line  1 . Swaging of the deformable annular retainer  40  to the aircraft coolant line  1  may occur when the coupler  10  is first moved to the engaged position, or the deformable annular retainer  40  may be pre-swaged to the aircraft coolant line  1  using a swaging tool (not shown) designed for this purpose, as is well known to those skilled in the art. The deformable annular retainer  40  will be described herein as a two-part construction, having a pair of ferrules  42 ,  54 . However, it is contemplated that a one-piece deformable annular retainer  40  could be provided. 
     The deformable annular retainer  40  includes a front ferrule  42 , as shown in  FIG. 3 . The front ferrule  42  is a substantially annular member that is typically fabricated from a deformable metallic material. The front ferrule  42  has an inner periphery  44  and an outer periphery  46  wherein the inner periphery  44  is adapted to engage the outer periphery  2  of the aircraft coolant line  1 . A slight exterior taper  48  is located adjacent to the outer periphery  46  of the front ferrule  42  and substantially adjacent to the inner periphery  44  of the front ferrule  42 . The exterior taper  48  extends at an acute interior angle with respect to the inner periphery  44  of the front ferrule  42 , thus creating a variable thickness cross-section for at least a portion of the front ferrule  42 . The exterior taper  48  is adapted to act as an engagement surface for engagement with the coupler body  70 . A radially extending rear face  50  of the front ferrule  42  is adjacent to the outer periphery  46  of the front ferrule  42  and extends substantially perpendicular thereto. An interior taper  52  extends at an obtuse angle with respect to both the rear face  50  and the inner periphery  44  of the front ferrule  42 . This creates a small, variable width gap between the front ferrule  42  and the outer periphery  2  of the aircraft coolant line  1  toward the rear of the inner periphery  44  of the front ferrule  42 . Both the rear face  50  and the interior taper  52  are adapted to act as engagement surfaces for engagement with the back ferrule  54 . 
     The deformable annular retainer  40  also includes a back ferrule  54 , as shown in  FIG. 4 . The back ferrule  54  is a substantially annular member fabricated from a deformable material, most typically a deformable metallic material, as similarly described with respect to the front ferrule  42 . The back ferrule  54  has an inner periphery  56  and a stepped outer periphery having a first outer periphery portion  58  and a second outer periphery portion  60 . In cross section, the inner periphery  56 , the first outer periphery portion  58 , and the second outer periphery portion  60  are substantially parallel. The second outer periphery portion  60  has a larger diameter as compared to the first outer periphery portion  58 . The first and second outer periphery portions  58 ,  60  are separated by a radially extending shoulder  62  that is adjacent and substantially perpendicular to both the first outer periphery portion  58  and the second outer periphery portion  60 . The radially extending shoulder  62  is adapted to act as an engagement surface for engagement with the rear face  50  of the front ferrule  42 . Opposite the radially extending shoulder  62 , a front face  64  is separated from the first outer periphery portion  58  by a chamfer  66  that forms obtuse interior angles with both the front face  64  and the first outer periphery portion  58 . The front face  64  meets the inner periphery  56  of the back ferrule  54  substantially perpendicularly. Both the front face  64  and the chamfer  66  of the back ferrule  54  are adapted to act as engagement surfaces for engagement with the interior taper  52  of the front ferrule  42 . Opposite the front face  64 , a rear face  68  extends from the inner periphery  56  to the second outer periphery portion  60  of the back ferrule  54  at a slight angle or taper. The rear face  68  of the back ferrule  54  is adapted to act as an engagement surface for engagement with the radially extending shoulder  32  of the nut  20 . 
     As best shown in  FIG. 5 , the geometry and size of the coupler body  70  are adapted to permit selective engagement of the coupler body  70  with the aircraft coolant line  1 , the deformable annular retainer  40 , and the nut  20 . The coupler body  70  extends along a longitudinal axis  70   a  and has an outer periphery  72 , an inner periphery  74 , and a passageway  76  that is defined by the inner periphery  74 . The coupler body  70  extends from a first end  78  to a second end  80  and is shown and described herein as substantially symmetrical about a plane perpendicular to its longitudinal axis, and thus, the coupler body  70  serves as a union coupler for joining the aircraft coolant line  1  to a second aircraft coolant line (not shown) at the opposite end of the coupler body  70  in a similar manner. However, the present invention is not necessarily limited in this manner, as it should be recognized that a single-ended coupler body  70  could be provided for use in other aircraft cooling system applications. 
     The outer periphery  72  of the coupler body  70  is sized so that it may be at least partially disposed within the nut  20 . In particular, a screw thread  88  is provided on the outer periphery  72  of the coupler body  70  for threadingly engaging the screw thread  34  on the second inner periphery portion  30   b  of the nut  20 . Accordingly, the nut  20  and the coupler body  70  may move between an unthreaded position, wherein the nut  20  and the coupler body  70  are threadingly disengaged, and a fully threaded position, wherein the screw thread  88  of the coupler body  70  is threadingly engaged with the screw thread  34  of the nut  20  to the greatest extent possible. 
     The inner periphery  74  of the coupler body  70  defines the passageway  76  in which the aircraft coolant line  1  is received. Near a midpoint between the first end  78  and the second end  80  of the coupler body  70 , a shoulder  86  may be provided within the coupler body  70 . The shoulder  86  is a constriction that defines an internal diameter smaller than the external diameter of the aircraft coolant line  1 , and thus, the shoulder  86  controls the maximum insertion of the aircraft coolant line  1  into the coupler body  70 . Between the shoulder  86  and first end  78  of the coupler body  70 , the minimum internal diameter of the passageway  76  is at least as large as the outer periphery  2  of the aircraft coolant line  1 . 
     To provide engagement of the coupler body  70  with the deformable annular retainer  40 , a chamfered engagement surface  82  is formed in the inner periphery  74  of the coupler body  70  adjacent to the first end  78  of the coupler body  70 . In particular, the chamfered engagement surface  82  is engageable with the exterior taper  48  of the front ferrule  42  of the deformable annular retainer  40 . The chamfered engagement surface  82  provides the largest internal diameter for the passageway  76  adjacent to the first end  78  of the coupler body  70 , and the internal diameter of the passageway  76  narrows toward the interior of the coupler body  70  throughout the length of the chamfered engagement surface  82 . 
     Further inward on the inner periphery  74  of the coupler body  70  from the chamfered engagement surface  82 , an annular groove  84  is formed in the inner periphery  74  of the coupler body  70 . The annular groove  84  is sized so that the o-ring  90  may be disposed therein. The o-ring  90  is an elastic sealing ring, as well known in the art, and may have a substantially round cross-section, a substantially square cross-section, or some other suitable cross-sectional shape. 
     In  FIG. 6 , the coupler  10  is shown in the disengaged position, wherein the coupler body  70  is not sealed with respect to the aircraft coolant line  1 . Accordingly, the aircraft coolant line  1 , the nut  20 , and the deformable annular retainer  40  are at least pre-assembled but are not engaged with the coupler body  70  or the o-ring  90 . In the disengaged position, the nut  20  is disposed on the aircraft coolant line  1 , thereby defining an annular recess  36  between the outer periphery  2  of the aircraft coolant line  1  and the second inner periphery portion  30   b  of the nut  20  and extending from the second end  24  of the nut  20  to the radially extending shoulder  32  of the nut  20 . The deformable annular retainer  40  is disposed on the aircraft coolant line  1  and within the annular recess  36 , such that the radially extending shoulder  32  of the nut  20  abuts the rear face  68  of the back ferrule  54 . 
     In  FIG. 7 , the coupler  10  is shown in the engaged position, wherein the coupler body  70  is sealed with respect to the aircraft coolant line  1  so that fluid, such as air conditioning coolant, may flow between the aircraft coolant line  1  and the coupler body  70  without leaking. In the engaged position, an end portion  3  of the aircraft coolant line  1  is at least partially disposed within the coupler body  70 , and the o-ring  90  sealingly engages the inner periphery  74  of the coupler body  70  and the outer periphery  2  of the aircraft coolant line  1 . The coupler body  70  is at least partially disposed within the annular recess  36  defined between the nut  20  and the end portion  3  of the aircraft coolant line  1 , and accordingly, the screw thread  34  on the nut  20  is engaged with the screw thread  88  on the coupler body  70 . 
     Comparing  FIG. 6  to  FIG. 7 , movement of the coupler  10  from the disengaged position to the engaged position will be readily understood. In the disengaged position, the aircraft coolant line  1  and the coupler body  70  are positioned so that the longitudinal axis  1   a  of the aircraft coolant line  1  and the longitudinal axis  70   a  of the coupler body  70  are substantially aligned, so that the first end  78  of the coupler body  70  faces the second end  24  of the nut  20 . The aircraft coolant line  1  is moved into the passageway  76  in the coupler body  70  and into sealing contact with the o-ring  90 . The nut  20  is then engaged with the coupler body  70  by engaging the screw thread  34  on the second inner periphery portion  30   b  of the nut  20  with the screw thread  88  on the outer periphery  72  of the nut  20 . As the nut  20  is threaded onto the coupler body  70 , the coupler body  70  is drawn into the annular recess  36 , and the chamfered engagement surface  82  on the inner periphery  74  of the coupler body  70  is drawn into engagement with the exterior taper  48  of the front ferrule  42 . At the same time, the radially extending shoulder  32  of the nut  20  engages the back ferrule  54  and causes engagement of the front ferrule  42  and the back ferrule  54  with one another. In response to the axial compression placed upon them by the nut  20  and the coupler body  70 , the front ferrule  42  and the back ferrule  54  deform radially, causing them to seal and frictionally engage the aircraft coolant line  1  and the coupler body  70 . 
     In use, a user connects the aircraft coolant line  1  to the coupler body  70  by moving the coupler  10  from the disengaged position to the engaged position. The user first aligns the aircraft coolant line  1  with the coupler body  70  and then inserts the aircraft coolant line  1  into the passageway  76  until the aircraft cooling line  1  abuts the shoulder  86  of the coupler body  70 , and the o-ring  90  engages the outer periphery  2  of the aircraft coolant line  1  with the o-ring  90  to create a first seal between the coupler body  70  and the aircraft coolant line  1 . The user then threads the nut  20  onto the coupler body  70 , moving the nut  20  to the fully threaded position with respect to the coupler body  70 . In doing so, the user causes the front ferrule  42  and the back ferrule  54  of the deformable annular retainer  40  to engage the nut  20  and the coupler body  70 , respectively, thereby swaging the deformable annular retainer to the aircraft coolant line  1  and creating a second seal between the coupler body  70  and the aircraft coolant line  1 . Furthermore, the threaded engagement of the nut  20  and the coupler body  70  maintains engagement of the coupler body  70  and the deformable annular retainer  40 . 
     Once in the fully engaged position, the aircraft coolant line  1  is sealed with respect to the coupler body  70  by both the o-ring  90  and the deformable annular retainer  40 . 
     To return the coupler  10  to the disengaged position, the user moves the nut  20  to the unthreaded position and removes the aircraft coolant line  1  from the coupler body  70 . 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.