WO1988000503A1

WO1988000503A1 - Improvements in and relating to tube expanders

Info

Publication number: WO1988000503A1
Application number: PCT/AU1987/000219
Authority: WO
Inventors: Heather Joan Lind
Original assignee: Heather Joan Lind
Priority date: 1986-07-16
Filing date: 1987-07-15
Publication date: 1988-01-28
Also published as: AU7703887A; GB2203078B; AU603596B2; GB8807140D0; CA1293430C; BE1001949A3; SE8800986D0; FR2601605B1; GB2203078A; FR2601605A1

Abstract

A tube expander tool (10) comprising a tool body (11), an axially movable mandrel (17) extending through the body and having a tapered end (37), jaw mounting means (18) coupled to the tool body (11) and comprising a plurality of expandable jaw elements (55) mounted for radial displacement upon axial movement of the mandrel (17), an adjustable tool head (13) between the tool body (11) and the jaw mounting means (18) and being movable axially in relation to the tool body (11), and locking means (52) to lock the tool head (13) against axial movement when the tool head (13) has been selectively positioned, whereby the amount of expansion of the jaw elements (55) can be accurately controlled.

Description

"IMPROVEMENTS IN AND RELATING TO TUBE EXPANDERS"

This invention relates to improvements in and to tools for expanding the ends of tubes/pipes, and in particular it relates to tube expanders of the type in which a plurality of jaw elements are carried in a jaw mount to be expandable by a tapered mandrel actuated by a cam connected with a pivoted handle carried on the tool body which also has a fixed handle extending therefrom, the arrangement being such that by manipulation of the pivoted handle, the mandrel is moved axially into and out of the jaw elements to expand the jaw elements, which have a complementary inner face, to in turn expand a tube end fitted over the jaw elements.

Tube expanders of the aforementioned type are well known and in this regard reference is made to Australian Patent Specification numbers 501,090 and 515,159.

Certain problems exist with this type of apparatus mainly due to the force required to expand the ends of tubes, such as copper tubes, and the need to have the expansion accurately controlled so that when for instance one end of the tube is to be expanded and the end of another tube fitted into it and brazed or the like, the fit shall be such that correct sealing of one end to the other will result and will be capable of withstanding the necessary pressures which need to be carried by tubes of this type.

A further problem with prior art devices is the requirement for fine tolerances during the manufacture of the tool, specifically the mandrel, the cam handle and the body. Furthermore, owing to wear, not infrequently the cam handle and/or the mandrel need replacement.

One object of the present invention is to provide an improved tube expander tool which is able to give very accurate adjustment of the expansion of the jaws. A further object is to provide a satisfactory type of cam on the movable handle and anti-f iction assembly between the cam on the handle and the mandrel which will ensure that the force required to move the mandrel forward is minimised. A still further object of this invention is to provide a tube expander, the manfacture of which is very much simplified and eliminates the need to maintain close tolerances in the production of the tool body. Yet another object of this invention is to provide a tube expander which will enable wear to be adjusted out, and which has simple, inexpensive replacement parts rather than having to replace main component parts of the tool through wear. According to one aspect of this invention, a tube expander is provided with an adjustable tool head between the tool body and the jaw mount, the head being movable axially in relation to the tool body and is axially aligned with both the mandrel and the jaw mount. More specifically, in one of its aspects, the invention is directed to an improvement in a tool for expanding pipe or tube ends of the type comprising a tool body having a passageway provided therein, an axially movable mandrel located in the passageway and having a tapered end, jaw mounting means arranged to be coupled with respect to the tool body and comprising a plurality of expandable jaw elements which are mounted for radial displacement upon axial movement of the mandrel, the tool body having a fixed handle projecting therefrom and a pivotal lever arm carried thereon, the pivotal lever arm being provided with a cam at or near its pivoted end, the arrangement being such that by manipulation of the lever arm, the cam co-acts with the mandrel to cause the mandrel to move axially into and out of the jaw elements to thereby expand same and to in turn expand a- tube end fitted over the jaw elements, the improvement comprising an adjustable tool head having a central opening extending therethrough and attachable to the tool body to be co- axially aligned with and between the tool body and the jaw mounting means, with the mandrel passing through the opening in the tool head, the attachment between the head and the tool body permitting the position of the tool head to be axially adjusted with respect to the tool body, and locking means to lock the head against axial movement when the tool head has been selectively positioned, whereby the amount of expansion of the jaw elements (and thereby the amount of expansion imparted to the tube end fitted over the jaw elements) can be accurately controlled by selectively positioning the tool head axially in relation to the tool body and locking the tool head in the selected position.

Because the adjustable tool head can be axially moved when the lock screw or similar device is released, the exact amount of expansion can be controlled by simply axially moving the head and then locking it when at the required extension which of course then governs the amount of expansion of the jaws, as the taper on the end of the mandrel engages the inner faces of the jaws. Furthermore, the use of an adjustable head greatly simplifies the manufacture of the tool in that the need for fine tolerances in the production of the tool body, cam handle and mandrel, is removed.

Preferably, the tool head comprises an axial hollow tail which engages neatly into the passageway in the body, the tail being adapted to be locked against axial movement when a selected position for the head has been reached by means of a lock screw or the like, any form of locking being suitable to prevent axial movement when required. The tail is preferably externally screw- threaded and threadably engages an internal screw thread in the passageway of the tool body.

The tail and the passageway in the tool body can be splined or otherwise arranged to prevent rotation of the head in relation to the body if this is required 5 or where the body is made of a softer metal the aperture can be sleeved so that the sleeve engages the tail on the head.

The tool head preferably has a circular recess in the surface facing the end of the tool body, and the 10 body has an annular depending lip to engage into the recess so that there is a barrier to the ingress of foreign matter to the interengaging surfaces between the tail and the body.

Preferably, the head has a screw-threaded portion 15 engageable with the jaw mount in which the jaw elements of the jaw assembly are housed and the jaw elements are locked to the jaw mount to prevent axial movement in relation thereto but are free to move radially to allow the jaws t be expanded. 20 In order to more fully explain the present invention, an embodiment is described hereunder in some further detail with reference to and is illustrated in the accompanying drawings in which:

FIG. 1 is a perspective view of a tube expander 25. showing an expanding jaw assembly attached thereto;

FIG. 2 is a exploded perspective view of the tool holder shown in Fig. 1; and

FIG. 3 is a part longitudinal sectional view of the tube expander of this invention (the closed 30 position of the pivoted lever arm being shown in dotted lines).

In this embodiment, a tube expander assembly 10 comprises a tool body 11 formed with an axial passageway 12 extending therethrough, an adjustable tool head 13 35 coaxially aligned with the tool body 11, the tool head 13 having an axial bore 16 extending therethrough, a mandrel 17 axially displaceable in the bore 16, and an expandable jaw assembly 18 carried on the lower end of the tool head 13 coaxially therewith. The expanding jaw assembly 18 operates in accordance with known art and does not form any part of the present invention.

The tool body 11 is provided with a fixed laterally projecting handle 20 which is provided at its end with a handle grip 21. The upper end of the tool body 11 is formed to have a pair of upwardly projecting spaced apart lugs 22 between which a pivotal lever arm 25 is mounted by means of a transverse pivot pin 26 which passes through the lever arm 25 and the lugs 22. The lever arm 25 can be swung in the direction of arrow 27 shown in Fig. 3 from an open position shown in full lines through to a closed position shown in dotted lines in which the lever arm 25 is approximately parallelly aligned with the fixed handle 20.

The lever arm 25 is provided with a cam 28 at its inner end, the cam 28 having an arcuate-shaped peripheral cam surface 30, the cam 28 joining the lever arm 25 through a pair of opposed shoulders 31. A hardened spring steel cam facing 32 clips on to the cam 28 and engages the peripheral surface 30. The clip 32 comprises an arcuate-shaped portion which terminates at its ends in inturned flanges 35 whereby the clip 32 is able to be readily removed and replaced through resilient engagement with the cam 28.

The upper end of the mandrel 17 is provided with an enlarged head 36, whilst the lower end of the mandrel 17 comprises a tapered portion 37 which extends through the tool head 13 and into the jaw assembly 18. As the pivot pin 26 is mounted eccentrically in relation to the cam surface 30, upon actuation of the lever arm 25, the tapered mandrel 17 is axially displaced and moves into the jaw assembly 18. Unlike prior art devices where the upper end face of the mandrel engages directly against a co-operable cam face, in this embodiment, the enlarged head 36 of the mandrel 17 is provided with a transverse 5 recess 39 in which is located an antifriction roller 40 which is arranged to engage the cam facing 32 to reduce friction during the time that the cam facing 32 is in engagement with the mandrel 17 to move it axially into the jaw assembly 18.

ID: The tool head 13, in this embodiment, comprises a small diameter axially inwardly projecting tail 41 which has an externally screw threaded portion 44 which threadably engages the internally threaded passageway 12 of the tool body 11, and a large diameter externally

15 screw threaded portion 45 which is arranged to be screw threaded to the sleeve or collar 47 of the jaw assembly

18. The screw threaded portions 44, 45 are separated by an annular flange 48, the diameter which is larger than

-the outer diameter of the tool body 11. The'axially inner

20 face 49 of the flange 49 is provided with a circular recess 50 into which engages an annular depending lip 51 projecting from the end face of the tool body 11. With the tool head 13 screwed to the tool body 11, the lip 51 engages within the recess 50 and forms a barrier to the

25^' ingress of foreign matter to the interengaging surfaces between the tail 41 of the head 13 and the inner surfaces of the tool body 11.

In order to lock the tool head 13 against axial movement, when a selected position for the head has been

30 reached, there is provided a lock screw 52 which threadably engages in a radial aperture 54 formed in the wall of the body 11, the lock screw 52 when in its locked condition, engages against an unthreaded portion of the tail 41 adjacent its inner end. ^' 35 Construction of the jaw assembly 18 is in accord with known art and comprises a self-contained set of radially expandable jaw elements 55 which are mounted in the circular collar or sleeve 47 in such a way that the segments can radially expand but are constrained against any axial movement. The jaw elements 55 are shaped so as to form a conical recess into which the tapered end of the mandrel 17 engages in order to effect the expansion of the jaw elements 55.

In this embodiment, the pivotal lever arm 25 is formed of cast aluminium which contrasts with prior art devices wherein the movable handle is normally of hardened steel material. The replaceable hardened steel cam facing clip 32 can be readily removed and replaced in the event of any wear - instead of the entire lever arm as is required in prior art units. Furthermore, the antifriction roller, preferably of hardened steel, significantly reduces friction between the clip 32 and the mandrel 17 and thereby minimises wear between the parts, but still further the antifriction roller permits the device to be more readily actuated.

The jaw assembly of course can be variable in dimension and for instance, the depth of the jaws can be changed to allow the device to be used in tubes of difference diameters and at the same time the actual expansion of such tubes is variable by loosening the lock screw or similar device and positioning the tool head axially in relation to the tool body to select the required limit to which the jaws can be expanded. It will be realised from the foregoing that a simple and effective form of tube expander is provided and one which incorporates significant improvements in comparison to known prior art devices.

Claims

The Claims defining the invention are as follows:

1. In a tool for expanding pipe or tube ends of the type comprising a tool body having a passageway provided therein, a axially movable mandrel located in the passageway and having a tapered end, jaw mounting means arranged to be coupled with respect to the tool body and comprising a plurality of expandable jaw elements which are mounted for radial displacement upon axial movement of the mandrel, the tool body having a fixed handle projecting therefrom and a pivotal lever arm carried thereon, the pivotal lever arm being provided with a cam at or near its pivoted end, the arrangement being such that by manipulation of the lever arm, the cam co-acts with th mandrel to cause the mandrel to move axially into and out of the jaw elements to thereby expand same and to in turn expand tube end fitted over the jaw elements, the improvement comprising: an adjustable tool head having a central opening extendin therethrough and attachable to the tool body to^" be co-axially aligned with and between the tool body and the jaw mounting means, with the mandrel passing through the opening in the too head, the attachment between the head and the tool body permitting the position of the tool head to be axially adjuste with respect to the tool body, and locking means to lock the head against axial movement when the tool head has been selectively positioned, whereby the amount of expansion of the jaw elements (and thereby the amount of expansion imparted to the tube end fitted over the jaw elements) can be accurately controlled by selectively positioning the tool head axially in relation to the tool body and locking the tool head, in the selected position.

2. In a tool according to claim 1 wherein the tool head comprises an axially extending elongate hollow tail co-axial with said central opening and adapted to engage within the passageway of the tool body, and wherein the locking means comprises a lock screw extending radially through an opening in the wall of the tool body, the lock screw, when in its locked condition, lockingly engaging against the outer surfac of the tail of the tool head.

3. In a tool according to claim 2 wherein the tool head comprises a circular flange having an outer diameter which is slightly greater than the outer diameter of the tool body, the flange having a circular recess in the surface facing the end of the tool body, the tool body having an annular depending lip engageable within the recess when the tool head is attached to the tool body, to thereby form a barrier to the ingress of foreign matter into the interengaging surfaces of the tail and the passageway of the tool body.

4. In a tool according to claim 2 or claim 3 wherein the tail has an external screw thread which threadably engages an internally threaded portion formed in the passageway of the tool body.

5. In a tool according to any one of claims 1 to 4 wherei the tool head has an externally screw threaded portion arrange to threadably engage an internal screw thread in the upper ope end of the jaw mounting means.

6. In a tool according to any one of claims 1 to 5 wherei the tool body is provided with a pair of laterally aligned upwardly projecting spaced apart lugs, said lever arm being pivotally supported between said lugs by means of a pivot pin passing through the lever arm and the lugs.

7. In a tool according to any preceding claim, the furthe improvement comprising a replaceable cam facing of wear- resistant material removably secured to the cam, said cam facing engaging the inner end of said mandrel.

8. In a tool according to claim 7 wherein the inner end of the mandrel is provided with a recess in which is located an antifriction roller for engaging the cam facing.

9. In a tool according to either claim 7 or claim 8 wherein the cam facing is formed as an arcuate shaped resilien clip, said cam on the lever arm being correspondingly shaped, the cam facing being arranged to engage said cam with a snap- 5 fit.

10. In a tool according to any one of claims 7 to 9 wherein the lever arm is of cast aluminium and the cam facing is formed of hardened steel.

11. In a tool for expanding pipe or tube ends of the type comprising a tool body having a passageway provided therein, an axially movable mandrel located in the passageway and having a tapered end, jaw mounting means arranged to be coupled with

5 respect to the tool body and comprising a plurality of expandable jaw elements which are mounted for radial displacement upon axial movement of the mandrel, the tool body having a fixed handle projecting therefrom and a pivotal lever arm carried thereon, the pivotal lever arm being provided with ° a cam at or near its pivoted end, the arrangement being such that by manipulation of the lever arm, the cam co-acts with the mandrel to cause the mandrel to move axially into and out of the jaw elements to thereby expand same and to in turn expand a tube end fitted over the jaw elements, 5 the improvement comprising a replaceable cam facing of wear-resis ant material attached to the surface of said cam, and being engageable with the inner end of said mandrel with which the cam co-acts to cause the mandrel to move axially into and out of the jaw elements.

12. In a tool according to claim 11 wherein the inner end of said mandrel is provided with a recess in which is located an antifriction roller for rollingly engaging the surface of said cam facing.

13. In a tool according to either claim 11 or 12 wherein the cam facing is formed as an arcuate shaped resilient clip, said cam on the lever arm being correspondingly shaped, the cam facing being arranged to engage said cam with a snap-fit.

14. In a tool according to any one of claims 11 to 13 wherein the lever arm is of cast aluminium and the cam facing is of hardened steel.