AU628743B2

AU628743B2 - Expanding mandrel method and product produced thereby

Info

Publication number: AU628743B2
Application number: AU77373/91A
Authority: AU
Inventors: Christopher Daniel Sassella
Original assignee: Dowell Australia Ltd
Current assignee: Crane Enfield Metals Pty Ltd
Priority date: 1990-06-22
Filing date: 1990-06-22
Publication date: 1992-09-17
Anticipated expiration: 2011-05-28
Also published as: AU7737391A

Description

Ct-ir

AUSTRALIA

PATENTS ACT 1990 Form COMPLETE SPECIFICATION

(ORIGTNAL)

FOR OFFICE USE Short Title: Int. Cl: Application Number: Lodged: Complete Specification-Lodged: Accepted: Lapsed: *Published: S Priority: Related Art: 4* TO BE COMPLETED BY APPLICANT Name of Applicant: DOWELL AUSTRALIA LIMITED Address of Applicant: 6 ALBERT STREET, PRESTON 3072

VICTORIA

AUSTRALIA

Actual Inventor: Address for Service: GRIFFITH HACK CO., 601 St. Kilda Road, Melbourne, Victoria 3004, Australia.

4* Complete Specification for the invention entitled: EXPANDING MANDREL METHOD AND PRODUCT PRODUCED THEREBY The following statement is a full description of this invention including the best wechod of performing it known to me:- 1~ e~ 2 4 0 t0 EXPANDING MANDREL METHOD AND PRODUCT PRODUCED THEREBY Field of the -nvention This invention relates to an expanding mandrel I. 5 and to a product produced thereby and relates particularly but not exclusively to a mandrel suitable for making products which utilize tube or pipe materials. Typical examples of such products comprise fences such as swimming pool safety fences, grills and other similar products.

10 Description of Prior Art Hitherto in the art of producing swimming pool fences it has been common to provide tubular upright members which are interconnected to top and bottom rails which are situated at distances such as 12 cm from the extreme top and bottom ends of the upright members. The interconnection has been by a crimping of the rails against the upright tubular members. Such production has been relatively expensive and has not lent itself to on-sight fabrication owing t the need to have rather large crimping apparatus for affecting the necessary crimping to the rails.

!Oblect and Statement of Invention The present invention has been devised with the object of providing an improved expanding mandrel and products produced thereby which mandrel can, in one example, be used for on site construction of swimming pool fence panels.

Therefore in accordance with the first broad aspect of the present invention there may be provided an expanding mandrel for use in connecting pipe or tube so *9 S• passing in a close fitting relationship through an 4 t •c 15 aperture in a member, said mandrel having a hollow body portion with a forward nose for fitting within the pipe or tube and for 'locating longitudinally with the forward nose at the position of the aperture, whereby a mandrel pin can be used for engaging internally of said mandrel with at least the forward nose to cause it to expand radially outwardly as said mandrel pin is driven into the forward nose, the external surface of said forward nose having pipe or tube 0 deforming surfaces which will radially expand the pipe or tube in the region of said aperture when said forward nose is expanded radially by said mandrel pin so the pipe or tube will extend over surfaces of both faces of sa 4 ,d member at said aperture, thereby connecting the pipe or 1 tube to said member.

30 Most preferably the mandrel pin passes through the body of the mandrel towards the forward nose and the forward nose is hollow so that a forward end of said mandrel pin Can pass completely through said mandrel and wherein a mandrel pin relief is provided in said mandrel pin which will allow the forward nose to radially retract to enable said mandrel and said mandrel pin to be 4 withdrawn from said pipe or tube.

Products made by using the mandrel and mandrel pin are within the scope of the invention.

A method of producing products is also provided.

To that end there may be provided a method of connecting pipe or tube to a member, said pipe or tube passing in close fitting relationship through said aperture in a member; said method comprising inserting a hollow mandrel into said pipe or tube so two longitudinally spaced apart circumferentially extending surfaces of a forward nose locate at positions internally of said pipe or tube so that one is adjacent one face of said member and the other is adjacent the other face of said member, moving a mandrel pin past said forward nose to cause it to radially expand V0 15 to simultaneously deform surfaces of said pipe tube over S.both faces of said member, subsequently causing said 0: mandrel to radially retract by further movement of said r. mandrel pin, and then withdrawing said mandrel from said pipe or tube.

Brief Description of the Drawings In order that the invention can be more clearly ascertained 4444 4examples of preferred embodiments will now be described with reference to the accompanying drawings wherein, Figure 1 is a perspective view of one preferred 25 mandrel; Figure 2 is a perspective view of one preferred mandrel pin for the mandrel shown in Figure 1; Figure 3 is an end view of the mandrel shown in Figure 1 at the rear end Figure 4 is an end view of the forward nose end 5 of said mandrel; Figure 5 is a side view of the mandrel; Figure 6 is a view similar to Figure 5 taken on a section line along the longitudinal axis of said mandrel; Figures 7 through 10 respectively show various stages in operation of the mandrel and mandrel pin; Figure 11 is a perspective view of a product in the form of a swimming pool fence made with the mandrel; Figure 12 is a perspective view of a jig used for holding components of the fence shown in Figure 11 to permit easy assembly; Figure 13 shows a modification of the mandrel 99 ml for use with a different cross sectional pipe or tube to that in the previous embodiments; and Figure 14 shows how a grill can be manufactured e with the mandrel using various length pipes or tubes. 9.

l Detailed Description of Preferred Embodiment Referring now to Figures 1 through 6 it can be seen that there is provided a circular cross section mandrel 1 and a corresponding mandrel pin 3. The mandrel 1 is hollow and has a forward nose 5 and a rear end 7.

The mandrel 1 is made from a suitable steel and suitably hardened, The forward nose 5 has two circumferential extending ribs 9 and 11 on the outer surface. A trough 13 9 is provided between the ribs 9 and 11. It can be seen that the ribs 9 and 11 have a greater radial extent than a body portion 15 of the mandrel 1. It can also be seen that the trough 13 has a radially innermost extent 30 corresponding approximately to the radially outermost extent of the body portion 15. In other words, the bottom of the trouqh 13 has approximately the same diameter as the outer surface of the body portion 15. The body portion 15 has slots 17 machined therein which in the present embodiment provide four fingers 19, 21, 23, The respective fingers 19, 21, 23, 25 form respective 6 equally sized quadrant portions at the forward nose Figure 6 shows that the mandrel 1 has an inner bore 27 i.e. the mandrel 1 is hollow. The forward nose has a radially inwardly directed portion 2 Thus, the diameter of the bore is greater in the body portion than between the portion 29 at the forward nose 5 so the portion 29 has a smaller radial extent than the bore.

The mandrel pin 3 is of a length greater than the length of the mandrel 1 and has a forward nose 31 which is of a larger diameter than the diameter of the body portion 33 of the mandrel pin 3. The body portion 33 extends immediately from the forward nose 31 to a relief portion 35 of smaller diameter than that of the body portion 33. The relief portion 35 extends only a short length longitudinally of the mandrel pin 3. The leading surface of the forward nose 31 is curved slightly to assist entry into the bore 27 and to enable the mandrel ft pin 3 to have its forward nose 31 pass the nose 5 of the .4 mandrel 1. The mandrel pin 3 is made from a suitable steel which may be suitably hardened.

In use, the mandrel pin 3 is inserted into the bore 27 so that the forward nose 31 engages with the portion 29. It is then driven further into the nose 5 and as a consequence there will be radially expansion of at least the forward nose 5 of the mandrel 1. It can be seen S that the surfaces of the portion 29 which lead to the surfaces of the bore 27 are inclined to permit a smooth :.transition between the bore 27 and portion 29. Thus, the mandrel pin 3 can be driven into the mandrel 1 to cause the forward nose 5 of the mandrel 1 to radially expand.

As the mandrel pin 3 is driven further into the bore 27, the portion 29 will locate within the relief 35 in the mandrel pin 3 and allow the forward nose 5 to radially retract. This will be explained later in relation to Figures 7 through Referring now to Figures 7 through 10 it can be

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7 seen how the mandrel 1 and mandrel pin 3 are used to fix a pipe or tube to a member.

Figure 8 shows that a metal such as an aluminium pipe or tube 37 has been passed through an aperture in a metal such as an aluminium member 39 in close fitting relationship with the aperture. In other words, the diameter of the aperture approximately equals the outer diameter of the pipe or tube 37 so that the pipe or tube 37 can be neatly received within the aperture. Typically the member can comprise a plate. The mandrel 1 is inserted through the hollow pipe or tube 37 so that the forward nose 5 locates adjacent the aperture with the ribs 9 and 11 adjacent each of the respective faces of the 0 t member 39 and the trough 13 generally aligned with the 0 :11 15 member 39. Thus, it can be seen that the spacing of the ribs 9 and 11 is chosen to suit a particular thickness of member 39. The spacing of the ribs 9 and 11 is greater ,F than the thickness of the member 39 but the exact spacing 4, is determined by the desired appearance of the external surfaces of the product at the connection of the pipe or tube 37 to the member 39.

Referring now to Figure 9 it can be seen how the mandrel 3 has buen driven so that its forward nose 31 is adjacent the forward nose 5 of the mandrel 1. Thus, the forward nose 31 of the mandrel 3 has entered the portion 29. Accordingly, the mandrel pin 3 has caused the mandrel fingers 19, 21, 23, 25 to expand radially outwardly to, in turn, cause the material of the pipe or tube 37 to 04 4 radially expand about both faces of the member around the o 30 aperture. Thus, it can be seen there is provided deformations 41 and 43 of the pipe or tube 37 which secure the pipe or tube 37 relative to the member 39.

In Figure 10 the mandrel pin 3 has been driven through the mandrel 1 so that the portion 29 locates within the relief portion 35 of the mandrel pin 3. Thus, the fingers 19, 21, 23, 25 of the mandrel 1 are radially -i I- c 8 retracted to their normal free position so that the ribs 9 and 11 are radially innermost of the inner diameter of the pipe or tube 37. The mandrel 1 has therefore effected a radially outward expansion of the pipe or tube 37 at the region of the aperture so there will be surfaces 41 and 43 radially expanded in the pipe or tube 37 which will hold the pipe or tube 37 relative to the member 39.

Because the mandrel 1 is made from steel it has a resilient nature and thus the radial expansion of -he fingers 19, 21, 23, 25 will not permanently deform the mandrel 3 so that the fingers 19, 21, 23, 25 can return to their original free position so that the ribs 9 and 11 at the forward nose 5 of the mandrel 1 will be radially Vt t innermost of the pipe or tube 37 when portion 29 is located in relief 35. Thus, the mandrel 1 and the mandrel pin 33 can be withdrawn from the pipe or tube 37 after the connection has been made.

S, Figure 10 shows how a collar 45 is fitted over the mandrel 1 so that the collar 45 locates against the head 7 and against the top of the pipe or tube 37. Thus, the collar 45 serves as a spacer to correctly locate the position of the forward nose 5 of the mandrel 1 relative to the member 39. In this way, a single mandrel and corresponding mandrel pin 3 can be provided and by using appropriately lengthed collars 45, the mandrel 1 and Q6mandrel pin 3 can be used to provide attachment of the pipe or tube 37 to the member 39 at desired spacing from the free end of the pipe or tube 37.

Referring now to Figure 11 there is shown one 30 preferred form of fencing made using the mandrel shown in Figures 1 through 10. The fencing shown in Figure 11 can be of metal such as of aluminium and therefore suitable for use in swimming pool fencing situations or other situations. Here there is provided a lower rail 47 and an upper rail 49. Each of the lower rail and upper rail 47 and 49 are provided from U-shaped extruded aluminium. A 9 series of posts 51 are shown fitted and connected with the lower and upper rails 47 and 49. In each case the U-shaped lower and upper rails 47 and 49 are down turned so that water will not collect between the arms thereof.

The posts 51 can comprise the pipe or tube 37 previously referred to. The lower and upper rails 47 and 49 comprise the member 39 previously referred to with suitably spaced and ized apertures therein.

Referring now to Figure 12 there is shown a jig 53 which can be manufactured from chip board or other cheap board like material to hold the rails 47 and 49 and the posts 51 in desired positions prior to introduction of the mandrel 1 to effect connection. Here it can be seen there are provided channels 55 and 57 and further channels 59 at right angles to channels 55 and 57. The channels and 57 and 59 can be made with a suitable router or other machining device. Thus, the rails 47, 49 can be placed in the channels 55, 57 and the posts 51 passed through the apertures in the rails 47, 49 which align with the positions of the grooves 59. Thus, the jig 53 will suitably hold the components in their required spaced relationships so that an operator can insert the mandrel 1 and the mandrel pin 3 successively into the posts 51 to LI Cause the necessary connection to be made to the rails 47, 49.

S..Referring now to Figure 13 there is shown a further example of a mandrel within the scope of the present invention. In this case, the cross section of the mandrel ts not circular but square and is used with square cross-section pipe or tube. Here it can be seen there are provided four fingers 61, 63, 65 and 67 and each has relevant ribs 9 and 11 on the outer surface which correspond with the ribs 9 and 11 in the previous embodiment. It is also noted there is a considerable space between the adjacent side edges of the fingers 61, 63, 65, 67 at the forvard nose end. This is provided to 10 inhibit the mandrel from expanding directly at sharp corners and tearing material of the pipe or tube at its corners. Thus, appropriately shaped mandrels can be provided for differing cross section pipes or tubes and still be within the scope of the invention.

Referring now to Figure 14 there is shown an example of a grill which can be used for a security door.

The grill has a series of horizontally extending rails 69 suitably fastened to an outer door frame 71. The grill is produced by having a series of tubular posts 73 and fastened to the respective rails 69 in a manner described in the previous embodiments. If desired the rails 69 can be tubular. Thus, it can be seen that by using the mandrel described herein it is possible to create desired grills which would not otherwise be possible without the use of dedicated machinery. The fact that there is provided outwardly swollen surfaces 41, 43 around the aperture in the member 39 does not detract from the overall aesthetic appearance of the produc..

It should be appreciated that many modifications may be made to the present invention without departing from the spirit and scope thereof. For example, it may be possible to provide a series of similar mandrels 1 and 1 mandrel pins 3 mounted together as a single tool so that the single tool can be inserted into various pipes or tubes 37 simultaneously so that by a single movement of all of the mandrel pins 3 there can be simultaneous connection of all of the pipes or tubes to the member 39.

Also, in the mandrels 1 shown as examples there 30 have been four fingers. For circular or square cross sectional shaped tube or pipe this has been found satisfactory. It should be noted, however, that a different number of fingers could be provided, the exact number being dstermined by the cross sectional shape of tube or pipe and the required quality of expansion needed.

Instead of the mandrel pin 3 passing through the 11 bore 27 from the rear end 7 to the nose 5, the mandrel pin 3 may be arranged to pass into the forward nose 5. In this case, the expanding mandrel 1 can be expanded by pulling the mandrel pin 3 from the mandrel 1 outwardly of the nose 5. Suitable means to effect such pulling may be implemented. One such means may comprise hydraulic means; another may comprise mechanical linkage means.

These and other modifications may be made without departing from the ambit of the invention the nature of which is to be determined from the foregoing description.

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Claims

2. An expanding mandrel as claimed in claim 1 having a central longitudinally extending bore through which said mandrel pin can move, said forward nose having internal surfaces provided on a radially, inwardly directed portion which has a smaller radial extent than that of said bore.
3. An expanding mandrel as claimed in claim 2 having fingers extending longitudinally from the forward nose along said body portion which can expand radially outwardly as said mandrel pin is driven into the forward nose.
4. An expanding mandrel as claimed in claim 3 wherein said fingers are provided by having slits in said mandrel extending from the forward nose along said body portion. An expanding mandrel as claimed in any one of the preceding claims wherein said hollow body portion will enable a mandrel pin to enter or pass from the forward nose. r I" 13
6. An expanding mandrel as claimed in claim 5 wherein said hollow body portion will enable a mandrel pin to enter from a rear end of said body portion opposite said forward nose.
7. An expanding mandrel as claimed in claim 6 wherein said rear end of said body portion opposite said forward nose is provided with a head which can be used as a stop to determine the extent to which said mandrel Ls inserted into said pipe or tube.
8. An expanding mandrel as claimed in any one of the preceding claims including a mandrel pin therefor, said mandrel pin having a fox-rward nose for engaging with the internal surfaces of said mandrel at said forward nose, :9 ,4 there being a relief immediately behind said forward nose 0 of said mandrel pin so that when said mandrel pin is driven 00 through said body portion towards said forward nose of said mandrel the mandrel will expand radially as said forward V nose of said mandrel pin engages with the internal surfaces of said forward nose, and upon further driving in the same direction said internal surfaces of said mandrel will pass into said relief whereby to allow said mandrel to retract radially inwardly, thereby permitting said mandrel and said mandrel pin to be withdrawn from said pipe or tube after it has been connected thereby to said member. "004 0:
9. An expanding mandrel as claimed in any one of the preceding claims wherein said external surfaces of said forward nose of said mandrel comprise two longitudinally spaced apart circumferentially extending surfaces have a greater radial extent than 5aie' body portion. A method of connecting pipe or tube to a member, said R<HNA pipe or tube passing in close fitting relationship through 14 said aperture in a member; said method comprising inserting a hollow mandrel into said pipe or tube so two longitudinally spaced apart circumferentially extending surfaces of a forward nose locate at positions internally of said pipe or tube so that one is adjacent one face of said member and the other is adjacent the other face of said member, moving a mandrel pin into said fo-rward nose to cause it to radially expand to simultaneously deform surfaces of said pipe tube over both faces of said member, subsequently causing said mandrel to radially retract by further movement of said mandrel pin, and then withdrawing said mandrel from said pipe or tube.
11. A method as claimed in claim 10 comprising using a mandrel as claimed in any one of claims 1 to 9.
12. A method as claimed in claim 10 or claim 11 comprising using a jig to support said pipe or tube at a desired position relative to said member, said jig having means for locating said pipe or tube and further means for locating said member.
13. A method as claimed in claim 12 wherein said jig has r* means for locat':ng many pipes or tubes relative to said member, said means locating each of said pipes or tubes at desired spaced locations relative to said member, and connecting said pipes or tubes to said member whilst located by said jig.
14. A pipe -or tube connected to a member, produced by the method of any one of claims 10 to 13. A mandrel substantially as herein described with St.i rnference to the accompanying drawings.
16. A method substantially as herein described with reference to the accompanying drawings, DATED THIS 26TH DAY OF JUNE 1992 DOWELL AUSTRALIA LIMITED By Its Patent Attorneys GRIFFITH HACK CO. Fellows Institute of Patent Attorneys of Australia. *1 I I A.Y -LI ABSTRACT An expanding mandrEl is provided which can be used for connecting pipe or tube passing in close mating relation through an aperture in a member. The mandrel is hollow and a mandrel pin is used to pass internally of the mandrel to cause a forward nose to exi-:d radially outwardly. The external surfaces of the mand:'el have tube deforming surfaces (9,11) which expand the tube in the region of the aperture so the tube will extend of surfaces of both faces of the member. A method and a product made by use of the mandrel is also disclosed. 4 r 3 4 t 4: t I t'l '1 t SI i .I