AU671044B2 - A fastener - Google Patents

Description

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AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Doo o o o 000 00 0 0* 0 0 00 0 orr r ft r ero co r 9 «0 0 00 0* of o 'i Name of Applicant: Actual Inventor: Address for Service: Invention Title: Ross Equipment Australia Pty Ltd Victor George Ross Chrysiliou Moore Chrysiliou Solicitors Attorneys CMC Centre, 143 Sydney Road Fairlight, Sydney, NSW 2094 A Fastener i The following statement is a full description of this invention including the best method of performing it known to me:- 1 ~i- A Fastener 0 0 o o 00 C 0 00 O 000 000 *000 S00 00 This invention relates to a new fastener and more particularly one which, in certain embodiments, is useful as a retrofit replacement for conventional nut and bolt type fasteners. Even more particularly, certain embodiments are particularly useful in fastening wear plates.

Blind or "pop" type rivets and nut and bolt combinations are two common types of fasteners used to hold two items together. Rivets have the advantages of being inexpensive, easily and rapidly applied and, within limits, of providing consistent clamping forces. However, they have the disadvantage that different length rivets must be used with different thicknesses of material to be joined, otherwise the correct clamping force is not generated. Furthermore, rivets are generally not suitable where the two components being joined are subject to shear forces. In such circumstances, the shear forces will tend to loosen and eventually bend or break the rivet, resulting in failure to maintain the components correctly joined.

Nut and bolt combinations have the advantages of providing greater resistance to failure under shear loadings and of accommodating greater variations in thickness of the two components. However, nut and bolt combinations are more expensive than rivets and installation is more time consuming. Additionally, if a specific clamping force is required, use of a torque wrench or similar device is required.

The present invention aims to overcome at )?ast some of the disadvantages of rivets and nut and bolt combinations and provide a method which combines the relatively inexpensive nature and easy application of rivets with the durability and more forgiving nature of nut and bolt combinations.

Accordingly, in one broad form, the invention provides an adaptor for a rivei' which comprises a tubular shell having a preformed head at one end and a mandrel extending through the shell with an expander head adjacent the other end, for expanding at least a portion of the shell, when drawn toward the preformed head, to form a second head, to enable the rivet to be used in an oversize hole in a first article to secure the first article to a second article, the adaptor comprising: a hollow cylindrical sleeve with an external diameter sized to fit snugly within the oversize hole and having an internal diameter between the undeformed and deformed diameters of the shell; C)Li I 1 i i r 4 0.

ROSS.496 2 wherein, on formation of the second head, the sleeve deforms and expands outwardly so as to grip the first article.

On tensioning the rivet, the rivet mandrel deforms the rivet shell, which in turn deformrr the deformable sleeve outwardly. Where the oversize hole passes through the first article, the deformation of the deformable sleeve is drawn towards the rear face of the first article until it firmly compresses the two articles together. Continued tensioning of the rivet mandrel then causes the mandrel shaft to break.

When used in a blind hole, tensioning the rivet causes the deformable sleeve to expand outwardly and grip the inner surface of 'he blind hole. Deformation increases, as does the holding force, until the rivet mandrel shaft breaks.

Preferably, the adaptor is comprised of a plastics material. Nylon is preferred, but other plastics materials may be used.

Preferably, the internal bore is countersunk so that the preformed head of the 15 rivet is not exposed and hence liable to be worn away or otherwise damaged.

:0 The adaptor may be made integral with the second article to be secured or it may be separate. Where the adaptor is separate from the second article, preferably it has a flange and passes through the second article into the other first article. In 2 this way the compressive load holding the two articles together may be 20 transferred via the adaptor, rather than the rivet. In this way even if the preformed rivet head is worn or broken off, the adaptor still functions. However, it will be appreciated that a simple sleeve which passes into or through the oversize hole will suffice, with the load transferred via the preformed rivet head.

Where the adaptor has a flange, preferably the second article to be secured has a countersunk hole so the flange does not stand proud. The flange may be an annulus or a frusto conical annulus, in which case the countersinking will need to be conical as well. Alternatively, the flange may be square, rectangular, trapezoid or pyramidoid.

Tk ROSS.496 3 Preferably, the adaptor has gripping means to grip the rivet when inserted in it.

Preferably, the gripping means is an annular flange extending radially inwardly from the internal surface of the internal bore.

The invention also provides, in one broad form, a method of securing a first article to a second article using a rivet which comprises a tubular shell having a preformed head at one end and a mandrel extending through the shell with an expander head adjacent the other end for expanding at least a portion of the shell when drawn toward the preformed head to form a second head received in or through an oversize hole in the first article, the method comprising: i) inserting an adaptor into an oversize hole in the first article, the S adaptor comprising a deformable cylindrical s;eeve having an external diameter I to fit snugly within the hole and an internal bore with E diameter lying between the deformed and undeformed sizes of the rivet shell; ii) passing a rivet through an aperture in the second article and into the internal bore of the adaptor; and iii) tensioning the rivet so as to form a second head on the rivet shell and cause the deformable sleeve to grip the first article.

The invention shall be better understood from the following non-limiting escription of embodiments of the invention and the drawings, in which; Fig. 1 shows a first embodiment of the invention in an unassembled condition; Fig. 2 shows the embodiment of Fig. 1 in an assembled but unfastened condition; Fig. 3 shows the embodiment of Fig. 1 in an assembled and fastened condition; Fig. 4 shows an alternate embodiment of the invention.

Referring to Figures 1 to 3, there is shown a wear plate 10 intended to be attached to the undercarriage/bogie of a transport vehicle, such as a truck or railway vehicle. The part of the undercarriage/bogie, which is usually steel, to which the wear plate is attached is indicated at 12.

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T ON ROSS.496 a a a *r a o a a 900Z 0*0 0 a a. a Conventional wear plates are normally affixed to bogie 12 by a number of nut and bolt combinations, which pass through bores in the bogie 12, one of which is indicated at 14. The wear plate 10 according to the invention, however, is intended to be affixed to the bogie 12 utilising a standard blind or "pop" type rivet 16. It will be noted that the rivet 16 has a smaller diameter than the bore 14. The wear plate 10 has an integral, cylindrical extension 18, which extends perpendicularly to the inner face 20 of the wear plate. The extension 18 has a bore 22, which extends through to the front surface 24, so the rivet 16 may be inserted from the front face 24. Preferably the bore 22 is countersunk at the front o10 face 24 so the preformed head 26 of the rivet 16 will lie below the front surface 24 when installed. Whilst the countersinking is preferred when the invention is used as a wear plate, this is not essential.

The bore 22 has a larger internal diameter than the external diameter of the rivet 16, so the rivet is a clearance fit in the bore. The diameter of the bore 22 is 15 preferably the same as that specified for holes in articles fixed by that particular rivet. To aid installation, the bore 22 has an inwardly directed annulus 28, which has an inner diameter slightly less than the rivet 16, so that an interference fit is formed when the rivet is inserted. Thus the rivet may be inserted into bore 22 before the wear plate 10 is installed in position, without the rivet falling out. It will be appreciated that the annulus 28 is preferred but not essential.

The annulus 28 is preferably located adjacent the front surface 24 so that it will grip all rivets used, no matter what their length. However, neither the positioning of the annulus is not critical, nor is its width.

Referring in particular to Figure 2, it will be noted that in the embodiment shown, the mandrel end 30 of the rivet 16 does not extend beyond the free end 22 of the sleeve 18. The position of the mandrel end 30 relative to the sleeve 18 is not critical, so long as it is a certain distance from the rear face of the plate 12. This distance is dependent on the diameter of the bore in the steel plate, the thickness of the sleeve 18 and the size of the rivet 16 being used. Apart from this criteria, the mandrel end 30 may be positioned within the sleeve 18 or extend beyond it.

However, as will be explained below, the adaptor may be used in a blind hole.

*a0 -9#a o 9 :1 i :!j jj !ij '-i r ROSS.496 To fix the wear plate 10 to the bogie 12, the rivet 16 and wear plate 10 are positioned as in Figure 2. The rivet is then tensioned with a conventional rivet gun so as to draw the mandrel 30 towards the rivet head 26. The mandrel remains at the end of the rivet shell 36 as it is drawn toward the head and causes the shell 36 to bulge outwards, so forming a second head. This in turn causes the plastics sleeve 18 to also expand outwards fc.,,iing an annular deformadion 37.

Continued pulling of the mandrel 30 draws it and the deformation 37 in the plastics sleeve towards the bogie 12 until the deformation 37 bears against rear face 38. Continued retraction of the mandrel 30 will cause the deformation 37 to draw the wear plate 10 tightly against the bogie 12 until the tension in the mandrel shaft 40 reaches its predetermined breaking valve, at which tension, the shaft 40 breaks away from the mandrel 30, leaving the wear plate 10 permanently affixed to the bogie 12.

:o Once the wear plate 10 is affixed to the plate 12, the rivet head 34 is somewhat redundant. If the rivet head 34 is worn away, the deformed sleeves 18 and 36 will maintain the wear plate 10 fixed to the plate 12.

Fig. 4 shows a second embodiment of the invention in which the deformable sleeve 39 is separate rather than integral with the wear plate 10. In this embodiment the sleeve 39 has a flange 40 at its inner end. The wear plate 10 has 20 a bore 42 of the same diameter as that of the sleeve 39, which is countersunk with a bore 44 the same diameter as the flange 40, so the flange may sit recessed in the bore 44. As with the first embodiment, the internal bore of the sleeve 39 may be countersunk so that the rivet head is not exposed. This embodiment functions similarly to the first embodiment.

Both the embodiments described provide a number of advantages: i) By use of sleeves having different outer diameters, standard rivets may be used to replace different sized bolts.

ii) The grip range of a standard rivet/mandrel combination may be shortened or lengthened over industry standards. This can be achieved by varying the depth of the countersinking for the rivet head.

z L f ROSS.496 6 iii) The use of a plastics sleeve provides a fixing that is more forgiving than a normal rivet to shear forces.

With wear plates, the wear plate is subject to a shear load perpendicular to the rivet or bolt. If rivets alone are used, over time the rivets are loosened or broken by this shear force. However, a plastics sleeve, it has been found, provides some "give" to the wear plate, allowing slight movement, but does not result in failure over time.

iv) Electrical insulation is provided by use of a plastics sleeve. This can be important in certain situations. For example, with electric trains, uncontrolled electric currents frequently pass through the wheel bearings to ground. Such currents cause bearing damage and consequently premature replacement or failure. Use of an electrically insulating fixing can prevent such currents and damage.

Whilst the embodiments described utilise an adaptor which is integral with one of 1 the articles or passes through the article, ;t is to be appreciated that this is not essential. If desired the adaptor may consist of only the sleeve which is inserted S into the oversize hole with the rivet head bearing on the article to be fixed. Since the sleeve must be bigger than the aperture in the article being fixed, on tensioning of the rivet, the sleeve will not "pull through" the aperture in the article 20 but will still deform and hold the two articles together. With such an embodiment, the rivet is necessary to hold the two articles together if the rivet head is broken or worn away the fixing will fail. Accordingly, such an embodiment has less widespread applicability.

Because the rivet need not extend out of the free end of the sleeve, it is possible to utilise the fastener in a blind hole. In such circumstances, the external diameter of the adaptor sleeve will need to be selected to ensure that the adaptor sleeve deforms and holds against the blind hole wall and causes the rivet mandrel to break, without allowing the rivet mandrel to fully compress the rivet shell.

It will be appreciated that many modifications and variations may be made to the embodiments described herein by those skilled in the art without departing from the spirit and scope of the invention.

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Claims (18)

1. An adaptor for a rivet which comprises a tubular shell having a preformed head at one end and a mandrel extending through the shell with an expander head adjacent the other end for expanding at least a portion of the shell when drawn toward the preformed head to form a second head, to enable the rivet to be used in an oversize hole in a first article to secure the first article to a second article, i the adaptor comprising: a hollow cylindrical sleeve with an external diameter sized to fit snugly within the oversize hole and having an internal diameter between the undeformed i: 10 and deformed diameters of the shell; wherein, on formation of the second head, the sleeve deforms and expands outwardly so as to grip the first article.

2. The adaptor of claim 1 wherein a first end of the internal bore is countersunk for receiving the preformed head of the rivet. S 15 3. The adaptor of claim 1 or claim 2 wherein the sleeve is comprised of a plastics t L material.

4. The adaptor of any one of claims 1, 2 or 3 wherein the sleeve is integral with the second article. t 0 5. The adaptor of any one of claims 1 to 3 wherein the adaptor is separate from the second article and has a radially outwardly extending first flange at or near a first end.

6. The adaptor of claim 5 wherein the flange is annular.

7. The adaptor of any one of claims 1 to 6 further comprising gripping means to grip the rivet.

8. The adaptor of claim 7 wherein the gripping means comprises an annular flange extending radially inwardly from the surface of the internal bore of the sleeve, the flange having an internal diameter less than the external diameter of the shell of the rivet. f ro "'Ti ROSS.496 8

9. The combination of a second article and an adaptor as claimed in any one of claims 1 to 8. The combination of claim 9 wherein the second article has a passageway therethrough, in which the adaptor is received.

11. The combination of claim 5 wherein the first flange is received within the passageway.

12. The combination of a first article and the combination of any one of claims 9 to 11, wherein the oversize hole in the first article is blind.

13. A method of securing a first article to a second article using a rivet which 10 comprises a tubular shell having a preformed head at one end and a mandrel I. extending through the shell with an expander head adjacent the other end for i expanding at least a portion of the shell when drawn toward the preformed head to form a second head, received in or through an oversize hole in the first article, the method comprising: 15 i) inserting an adaptor into the oversize hole, the adaptor comprising a deformable cylindrical sleeve having an external diameter to fit snugly within the hole and an internal bore with a diameter lying between the deformed and t, undeformed sizes of the rivet shell; ii) passing a rivet through an aperture in the second article and into the internal bore of the adaptor; and iii) tensioning the rivet so as to form a second head on the rivet shell and cause the deformable sleeve to grip the first article.

14. The method of claim 13 wherein the adaptor is integral with the second article.

15. The method of claim 13 wherein the adaptor is separate from the second i article. 7i2 o, 1 I JK~: It I, I ROSS.496

16. The method of claim 15 wherein the adaptor has an outwardly extending flange at one end thereof and prior to step the adaptor is passed through the aperture so that the flange bears on the second article.

17. The method of any one of claims 13 to 16 wherein step I) comprises inserting the adaptor into a blind oversize hole.

18. The method of any one claims 13 to 17 wherein step ii) occurs before or after step i).

19. An adaptor, substantially as he: -in described with reference to the drawings.

20. A combination of an adaptor and a rivet substantially as herein described with 10 reference to the drawings.

21. A method of securing two articles together, substantially as herein described with reference to the drawings. a a ai t(Ct, 44 atIt at *I 4 ett I 4(44 Sc C 4 a (a Dated this 22nd day of April, 1996 ROSS EQUIPMENT AUSTRALIA PTY LIMITED by its Patent Attorneys CHRYSILIOU MOORE MARTIN j L_ 6 il-- ROSS-10.94\KR Abstract An adaptor (18, 39) to enable a rivet (16) to be used in an oversize hole (14) in a first article to secure a second article (10) to the first article the adaptor (18, 39) comprising a deformable cylindrical sleeve (18, 39), said sleeve having: 1) an internal bore (22) with a diameter lying between the undeformed and deformed sizes of the sleeve (36) of the rivet; and, 2) an external diameter sized to fit snugly within the oversize hole (14). a .aao a a. t a aat at a a t. 4 I- -1 1