Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D41/00—Application of procedures in order to alter the diameter of tube ends
  • B21D41/02—Enlarging
  • B21D41/026—Enlarging by means of mandrels
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D39/00—Application of procedures in order to connect objects or parts, e.g. coating with sheet metal otherwise than by plating; Tube expanders
  • B21D39/08—Tube expanders
  • B21D39/20—Tube expanders with mandrels, e.g. expandable

Definitions

• This invention relates to a tube expander and in particular it relates to a tube expander which can be used to expand a portion of a tube, preferably the end, to allow joining of the ends of two coaxially placed tubes and in particular it relates to an expander which can expand tubes of hard material such as hard drawn copper but which will be usable on soft copper tubing and other materials as well.
• the object of the present invention is to overcome the problems referred to above and to provide a tube expander which is relatively easy to operate so far as operating pressures are concerned and which will operate on harder material tubes without splitting and further will not damage the tube itself due to the need to hold it in grips against heavy axial forces applied during the expansion.
• the objects are achieved according to this invention by expanding the tube over the area defined for the expansion by commencing expansion remote from the tube expander and causing expansion linearly towards the expander, the device preferably consisting of an expansion die in segmented form which can be moved into the end of a tube to the distance over which the tube is to be expanded and is then expanded outwardly to make contact with the tube and expand the tube by radial pressure at a circular area, the expansion die being then moved towards the tube expander to progressively expand the tube.
• the end of the tube which is being expanded is simply resting against the expander itself so that the tube need not be otherwise gripped, although guide means can be provided if required, whereby, because the tube is progressively expanded linearly towards the expander, the force required is considerably less than by some other methods and also splitting of the tube does not generally occur because of the relatively circular contact only at the area of the expansion die remote of the end of the tube. Because the pull is toward the expander the tube does not need to be firmly gripped as the expansion die pulls the tube firmly to the expander to provide the necessary reaction force.
• the device can be constructed in various ways but according to a simple arrangement the expander can be of a similar form to the hand operated expanders used at the present time in which a head forms part of one handle and another handle is pivoted to the head to allow manipulation of a pull rod extending through the head, the head having jaws shaped to allow a tube of the required diameter to be engaged therein with faces against which the end of the tube rests, the pull rod having at its extremity a tapered portion and a flange and having, arranged to slide on the tapered portion, the expansion die which can be of segmented form by having longitudinally formed segments with the remote end of the expansion die given a fairly short radius and the die sloping back to a retaining ring for the sections of the die so that this expansion die can be pulled down onto the smaller part of the tapered portion on the pull rod as the pull rod is moved forwardly to position the expansion die at the locality where the inner end of the expansion is to occur, and by then moving the pull rod back the expansion die is forced outwardly as the
• the invention is characterised in that the expansion die is supported by a head and is arranged to be positioned in a tube through one end thereof to engage the inner surface of the tube at least remotely of the end of the tube, means being provided to expand the forward inserted end of the expansion die to effect an annular expansion of the tube at the forward end portion of the expansion die, means being also provided to pull the expansion die toward the head to progessively expand the end portion of the tube, means being provided on the head to engage the end of the tube being expanded to hold the tube against axial movement during the linear expansion action.
• the tube expander thus comprises a head having an aperture therethrough, a pull rod extending through the aperture, an expansion die positioned on a forward part of the pull rod, means to urge the expansion die forward on the pull rod, means to limit the forward movement of the expansion die on the pull rod, means on the pull rod to expand the expansion die when urged forward on the pull rod, means to pull back the pull rod in relation to the head, and a face on the head to engage the end of a tube to be expanded.
• FIG. 1 is a perspective view of the tube expander with the pull rod retracted.
• FIG. 2 is a similar view with the pull rod moved forward as when commencing a tube expansion.
• FIG. 3 Is a view of the tool as in FIG. 2 but to an enlarged scale, showing the tool sectioned on planes normal one to the other.
• FIG. 4 is a plan of the expansion die, with part of the pull rod shown, the spring being section.
• FIG. 5 is a longitudinal sectional view of the head and jaws and the expansion die mounted on the pull rod with a tube being pushed into position to be engaged by the jaws.
• FIG. 6 is a view similar to FIG. 5 but showing the tube pushed forward and engaged in the jaws with its end against the face of the jaws and with the pull rod pushed forward into the tube to position the expansion die at the location where the expansion of the tube is to commence.
• FIG. 7 is again a similar view to FIGS. 5 and 6 but showing the pull rod actuated to expand the expansion die, with the flange positioned against the end of the expansion die in readiness to commence a traverse along the tube, and
• FIG. 8 is a similar view but showing the expansion of the tube completed and showing the expansion die pulled back to the position where the tube is released from the expansion die and is releasable from the jaws.
• the head 1 has on it radially movable jaws 2 confined between a face 3 of the head 1 and a face 4 of a keeper 5 which is engaged on the head 1.
• the jaws 2 have a recess '6 at their inner ends and a reaction face 7 against which the end of a tube to be expanded rests, this reacton face 7 being adapted to take the axial force generated on the tube during the operation of the expansion die and thus forming the means for holding the tube without having to use any form of gripping device engaging the outside of the tube remote from the end as has been the practice heretofore.
• the pull rod 8 has at its end a tapered portion 9 and a flange 10.
• the expansion die 11 consists of a first and a second series of longitudinally divided segments 11A and 11B grouped about the pull rod 8 and held together by a ring 12 engaging circumferential grooves In the segments 11A and 11B of the expansion die 11.
• the forward end of the expansion die 11 has an annular surface 14 which defines the expansion required at the end of the tube, a sloping surface 15 forming a lead to the annular surface 14, the surface of the expansion die 11 sloping inwards from the annular surface 14 to provide an expansion lead 16.
• the inner surface 17 of the expansion die is shaped so that the expansion die 11 engages the tapered portion 9 of the pull rod 8 at the forward end 18 of the segments 11A and 11B of the expansion die, while the rear end 19 of the expansion die 11 rests on the pull rod 8 so that the segments 11A and 11B of the expansion die 11 can tilt to cause the forward ends 18 of the segments 11A and 11B to expand outwardly under action of the tapered portion 9, while retaining the rear end 19 in contact with the pull rod 8.
• the surface 14, together with the expansion lead 16, serve to expand the tube 20 when the pull rod 8 is moved rearwardly from the position shown in FIG. 6 to that shown in FIG. 7, at which stage the tube has an annular expansion 21 remote from its end.
• a spring 23 confined between the rear end of the expansion die 11 and a collar 24 which, in the illustrations, is shown as welded to the pull rod 8 but can be adjustable along the pull rod 8 by threading the pull rod and the collar 24 or by provided grub screws or the like to lock the collar 24 in position on the pull rod 8 at the position where the required force of the spring 23 is achieved to urge the expansion die 11 forward.
• the reason for using segments 11A and 11B of different form is to ensure that the expansion die 11 will form a true circular surface which will expand the tube without draw marks caused through gaps between the segments .
• the segments 11A are the main segments of the device but intermediate segments 11B fit between the main segments 11A and are tapered and angled such that the segments 11A and 11B can have a certain amount of longitudinal movement between them to complete a circle at the annular surface 14 and moreover to have the edges of the segments 11A and 11B at an angle to the line of the draw to ensure that the expansion of a tube takes place in true circular form without forming fins on the inside of the expanded portion.
• the angular interengagement is on the lines 11C, that is at the annular surfaces 14.
• the circumferential grooves in which the retaining ring 12 is accommodated are longer in the segments 11A than in the segments 11B so that when the device is pushed into a tube preparatory to expanding the end of the tube the segments can all accommodate themselves correctly in relation to the inner face of the tube, but when the initial expansion takes place which occurs because of the friction between the annular surface 14 of the segments and the inside of the tube 20 to be expanded all segments 11A and 11B will be pushed outward in the position they have assumed.
• the pull rod 8 with its tapered portion 9 and flange 10 is encircled at its forward portion by the segments 11A and 11B of the expansion die 11 and these segments 11A are free to move at the forward end 18 of the expansion die 11 under control of the tapered portion 9 of the pull rod 8, and when It is required to expand a tube 20, the tube is pushed in the direction of the head 1 as shown in FIG.
• annular surface 14 engages the inner face of the tube 20 and slides along the tube 20 as the pull rod 8 is advanced, the spring 23 being compressed at this stage to ensure that contact of the inside of the tube 20 by the annular surface 14 is retained as the pull rod 8 is advanced to the position shown in FIG. 6.
• FIG. 6 shows how the end of the tube 20 is engaged in the jaws 2 which are urged Inwards by a spring circlip 26 to have the shoulders 27 of the recess 6 on the jaws 2 engage the tube 20 and to have the end of the tube 20 engage the reaction face 7 on the jaws 2 to take the thrust.
• the expansion die 11 does not move axially but the forward end of the expansion die segments 11A and 11B move out to expand the effective diameter of the end of the expansion die 11 forming the annular expansion 21 to give a circumferential ridge.
• this movement forming the expanded portion 30 required on the tube 20.
• the movement between the head 1 and the pull rod 8 can be obtained by any suitable actuating members such as a pair of levers 32 and 33 , the lever 32 being connected to the body 29 which supports the head and the other lever 33 pivoted to the body 29 and having a connection (not shown) to the pull rod 8.
• actuating members such as a pair of levers 32 and 33 , the lever 32 being connected to the body 29 which supports the head and the other lever 33 pivoted to the body 29 and having a connection (not shown) to the pull rod 8.
• levers it Is possible to use a hydraulic mechanism which can readily be applied between the pull rod and the head.
• the form of the expansion die can of course be varied and instead of it being formed of separate segments it can take the form of an expanding ring with a rounded outer perimeter, that is rounded in cross-section, the purpose of the expansion die being to move outwardly and form an outwardly pressed circular ridge and to then move the expansion die axially in the tube while the end of the tube is held against the reaction face of the head to progressively linearly expand the tube.
• the device can be made with interchangeable heads to take different sizes of tube or the taper on the pull rod can be provided with adjusting means which allow the expansion die to have limited movement only on the taper of the rod such as by moving an end rim or collar axially along the pull rod or alternatively the expansion die itself can be attached to means which limit its outward movement on the taper to thereby determine its starting diameter and such adjustment can be indexed to allow the tool to be used on tubes of different size by appropriately positioning the control means for the position of the expansion die on the taper.

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Citations (2)

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• 1983
  • 1983-06-27 WO PCT/AU1983/000083 patent/WO1984000120A1/fr not_active Application Discontinuation
  • 1983-06-27 JP JP58502131A patent/JPS59501197A/ja active Pending
  • 1983-06-27 EP EP19830901887 patent/EP0112853A4/fr not_active Withdrawn

Patent Citations (2)

Non-Patent Citations (1)

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