Coupling for composite hose and method of making same

Abstract

A reinforced hose coupling including an end fitting having first and second, axially extending sections with the first section comprising a connector and a second section providing a nipple with external grooves. A metal ferrule is mounted on the nipple and is connected to the end fitting. The ferrule has an external depression formed in a side thereof. Two holes are formed in this depression and extend through the wall of the ferrule. A reinforced hose end having flexible tubular rubber or plastic layers is crimped between the ferrule and the nipple. The hose end has an outer wire extending about the exterior of the tubular layers. An end piece of this wire extends through the holes and across the depression helping to secure the hose end to the coupling and providing an indication to the user that the coupling is in usable condition. Preferably the ferrule is formed with a circumferentially extending internal rim at one end, which rim is forced into a circumferential groove formed in the end-fitting. A method and an apparatus are also provided for making the house coupling. The apparatus includes first and second annular dies each having a circular die opening with a predetermined minimum diameter. A mounting arrangement rigidly connects each die to a hydraulic ram so that each can be driven linearly along the exterior of the ferrule.

I therefore claim:  
     
         1 . A reinforced hose coupling comprising: 
 an end fitting having first and second, axially extending sections, said first section comprising a connecting element and said second section providing a nipple element having external grooves formed thereon;    a metal ferrule mounted on and about said nipple element and connected to said end fitting, said ferrule having a generally cylindrical wall and an external depression formed in a side of said wall and projecting radially inwardly towards said nipple element, two spaced-apart holes being formed in said depression and through said wall; and    a reinforced hose end having flexible tubular layers crimped between said ferrule and said nipple element, said hose end having a helical wire extending about the exterior of said flexible tubular layers, an end piece of said wire extending through said two holes and across said depression.    
     
     
         2 . A hose coupling according to  claim 1  wherein said depression is elongate in the circumferential direction of said ferrule and said two holes are formed at opposite ends of said depression.  
     
     
         3 . A hose coupling according to  claim 1  wherein said hose end also has an inner helical wire extending about the interior of said flexible tubular layers and an end portion of said inner helical wire extends along and engages said external grooves of said nipple element.  
     
     
         4 . A hose coupling according to  claim 2  wherein said tubular layers include one or more plastic tubular layers which extend axially beyond said helical wire that extends about the exterior of the tubular layers, the end portion of the plastic tubular layers located beyond said helical wire being pressed tightly between said ferrule and the nipple element and thereby forming a seal able to withstand high fluid pressure.  
     
     
         5 . A hose coupling according to  claim 1  wherein said ferrule is formed with a circumferentially extending internal rim at one end thereof and said rim extends into a circumferential groove formed in said end fitting in order to mechanically secure said ferrule to said end fitting.  
     
     
         6 . A hose coupling according to  claim 5  wherein said ferrule has a first axially extending portion with a first external diameter and a second, axially-extending portion with a second external diameter which is less than said first external diameter, and wherein the first portion of the ferrule extends about said helical wire.  
     
     
         7 . A hose coupling according to  claim 6  wherein said external grooves on the nipple element form a two start thread and said hose end has an inner helical wire extending about the interior thereof, an end portion of said inner helical wire extending along one of two spiral grooves formed by said thread.  
     
     
         8 . A hose coupling according to  claim 6  wherein said flexible tubular layers include layers of polypropylene fabric and film and said layers extend beyond an end of said helical wire that extends about the exterior of the tubular layers.  
     
     
         9 . A method of making a coupling for reinforced, flexible hose comprising: 
 providing a flexible hose reinforced by means of helical wire extending about the interior of said hose and having one end on which a coupling is to be provided, said hose including flexible tubular layers which axially extend beyond an end of said helical wire at said one end of the hose;    placing a metal ferrule over said hose and adjacent to said one end of said hose, said ferrule being formed with a circumferentially extending internal rim at an end of said ferrule closest to said one end of the hose;    inserting an end fitting into said one end of said hose, said fitting having first and second, axially extending sections, said first section comprising a connecting element that projects from said one end of the hose and said second section providing a nipple element with external grooves formed thereon, said nipple element being placed in said hose so that said helical wire extends along said external grooves, said end fitting having an external circumferential groove formed therein and spaced from the ends thereof,    swaging said metal ferrule with a first die and thereby driving said internal rim into said circumferential groove and mechanically connecting said ferrule to said end fitting and clamping a portion of said helical wire in said external grooves of said nipple element which secures said hose to said end fitting;    and swaging said metal ferrule with at least one follower die of smaller inner diameter than said first die and thereby clamping the tubular layers which extend beyond the end of said helical wire tightly between said ferrule and said end fitting in a sealing manner.    
     
     
         10 . A method of making a coupling according to  claim 9  wherein said end fitting is inserted into said one end of the hose by screwing the end fitting relative to said one end of the hose in order to thread said helical wire into said external grooves of the nipple element.  
     
     
         11 . A method of making a coupling according to  claim 9  wherein said metal ferrule is swaged with an initial follower die having a predetermined inner diameter smaller than the inner diameter of said first die and is subsequently swaged with a second follower die having an inner diameter smaller than said predetermined inner diameter.  
     
     
         12 . A method of making a coupling according to  claim 11  wherein said flexible hose is further reinforced by an outer helical wire which extends around the exterior of said flexible tubular layers, said tubular layers extend axially beyond an end of said outer helical wire, and the swaging step with the first die clamps portions of both helical wires between said ferrule and said end fitting.  
     
     
         13 . A method of making a coupling according to  claim 12  wherein said metal ferrule has an external depression formed in a side thereof, two, spaced-apart holes being formed in said depression, and an end piece of said outer helical wire is inserted through one of said two holes, is passed through said depression, and is then manipulated so as to pass out through the other of the two holes before said ferrule is swaged with the first die.  
     
     
         14 . A reinforced hose coupling comprising: 
 an end fitting having first and second axially-extending tubular sections, said first and second sections being separated by a circumferential groove formed in an exterior surface of said end fitting, said first tubular section comprising a connecting element and said second section having an external helical groove that spirals about its circumference;    a flexible hose end comprising flexible tubular layers of plastics or rubber material and an inner helical wire extending about the interior of said tubular layers, said second section of the end fitting extending into said hose so that said helical wire extends along and in said helical groove and circumferentially about said second section, an axial extension of said tubular layers extending beyond an adjacent end of the helical wire and along the exterior of said second section; and    a metal ferrule mounted on said hose end and extending around an end section of said helical wire and said axial extension of said tubular layers, said ferrule having an internal rim at one end which extends into said circumferential groove in order to mechanically connect said ferrule to said end fitting, wherein said axial extension of said tubular layers is clamped between said ferrule and said end fitting, thereby forming a fluid tight seal.    
     
     
         15 . A hose coupling according to  claim 14  wherein said flexible hose end also has an outer helical wire extending about the exterior of said flexible tubular layers and ending near said adjacent end of the inner helical wire.  
     
     
         16 . A hose coupling according to  claim 14  wherein said ferrule has a first, axially-extending portion with a first external diameter and a second, axially-extending portion with a second external diameter which is less than said first external diameter, and wherein the first portion of the ferrule extends around said inner helical wire and the second portion extends around said axial extension of said tubular layers.  
     
     
         17 . A coupling device for flexible, reinforced hose having a helical support wire extending about the exterior of flexible tubular layers, said device comprising: 
 an end-fitting including means for connecting the device to another fitting and a nipple element for insertion into an end of said hose; and    a metal ferrule for mounting on said end-fitting so that said ferrule extends around said nipple element and an end section of said hose, said ferrule having an external depression formed in a side thereof and two spaced-apart holes formed in said depression and positioned to receive an end of said helical support wire so that the latter can extend through said holes and across said depression.    
     
     
         18 . A coupling device according to  claim 17  wherein said depression is elongate in the circumferential direction of said ferrule and said two holes are formed in opposite ends of said depression.  
     
     
         19 . A coupling device according to  claim 18  wherein said ferrule has an internal rim at one end which is sized and adapted to extend into a circumferential groove formed in an exterior surface of said end-fitting in order to connect the ferrule to the end-fitting.  
     
     
         20 . Apparatus for making a coupling for flexible hose reinforced by means of a helical wire extending about the interior of said hose, said apparatus comprising: 
 a supporting device for holding one end of said hose and a generally cylindrical metal ferrule arranged over an end section of said hose during operation of the apparatus, said ferrule being formed with a circumferentially extending internal rim located at an end of said ferrule closest to said one end of the hose and having an initial first external diameter;    a first annular die forming a circular die opening having a minimum diameter a little smaller than said first external diameter;    a second annular die forming another circular die opening having a minimum diameter a little smaller than said minimum diameter of the first die;    a mounting arrangement for rigidly connecting each of said first and second dies to a hydraulic ram so that each die can be driven linearly along the exterior of said ferrule starting at the end of the ferrule having said internal rim,    the swaging action of said first die causing said end section of the hose, including an end portion of said helical wire to be clamped firmly between said ferrule and an end-fitting positioned within said end section of the hose, and causing said internal rim to be deformed radially inwardly into an annular groove formed around said end-fitting while a subsequent swaging action with the second die causes a relatively short end portion of the hose having no helical wire extending about its circumference to be sealingly clamped between said ferrule and said end-fitting, said further swaging action occurring only along a section of said ferrule immediately adjacent said short end portion of the hose.    
     
     
         21 . Apparatus for making a hose coupling according to  claim 20  including a third annular die forming another circular die opening having a minimum diameter a little smaller than said minimum diameter of the second annular die, said third die being usable for a further swaging action after use of said second die.  
     
     
         22 . Apparatus for making a coupling according to  claim 20  wherein each of the annular dies includes a split die ring made up of two semi-circular die sections and said mounting arrangement includes an annular mounting ring in which said die ring is detachably mounted.  
     
     
         23 . Apparatus for making a coupling according to  claim 22  wherein said mounting arrangement further includes a rotatable cam ring extending about said mounting ring and mounted thereon and a number of retaining pins having heads at their outer ends, said heads being arranged in said cam ring, wherein said pins can be moved by rotation of said cam ring from a first position where inner ends of said pins engage and hold said split die ring in said mounting ring to a second position where said pins are disengaged from said split die ring.  
     
     
         24 . Apparatus for making a coupling according to  claim 22  wherein said mounting arrangement includes a tubular extension mountable at one end thereof to said hydraulic ram and connectible at an opposite end thereof to said mounting ring, said tubular extension forming a chamber sized to accommodate said end-fitting and said ferrule during said swaging actions.  
     
     
         25 . Apparatus for making a coupling according to  claim 22  wherein each annular die has an annular outer surface engaging an annular inner surface of said mounting ring and both said outer surface and said inner surface extend at an acute angle ranging between 10 and 20 degrees to a central axis of the respective annular die as seen in cross-section through said central axis.  
     
     
         26 . Apparatus for making a coupling according to  claim 22  wherein each annular die has an annular outer surface engaging an annular inner surface of said mounting ring and both said outer surface and said inner surface extend at an acute angle of about 15 degrees to a central axis of the respective annular die as seen in cross-section through said central axis.  
     
     
         27 . Die apparatus for swaging a tubular metal body, comprising: 
 a split die ring forming a circular opening and made up of two semi-annular die sections each having a radially inner surface for engaging and shaping said metal body and a radially outer surface which in radial cross-section extends at an acute angle to a central axis of said circular opening;    an annular die body surrounding and supporting said die ring, said die body having an annular, sloping engagement surface in contact with said radially outer surface of the die ring and parallel thereto and said die body having a number of pin passageways that extend radially through the die body;    a number of holding pins each extending through a respective one of said pin passageways and having a head on a radially outer end thereof; and    a rotatable cam ring extending about said die body and having a number of slots formed therein and spaced about the circumference of the cam ring, each of said slots extending in a generally circumferential direction and having a respective one of the pins heads captured therein,    wherein said pins can be moved radially outwardly by rotation of said cam ring from a first position where inner ends of said pins engage and hold said split die ring in said die body to a second position where said pins are disengaged from said split die ring.    
     
     
         28 . Die apparatus according to  claim 27  wherein both said outer surface of said die ring and said engagement surface of the die body extend an acute angle ranging between 10 and 20 degrees to said central axis.  
     
     
         29 . Die apparatus according to  claim 28  wherein said acute angle is about 15 degrees.