GB2310904A

GB2310904A - Blind rivet nut for fixing three sheets

Info

Publication number: GB2310904A
Application number: GB9604910A
Authority: GB
Inventors: Daniel Robin Smith
Original assignee: Newfrey LLC
Current assignee: Newfrey LLC
Priority date: 1996-03-08
Filing date: 1996-03-08
Publication date: 1997-09-10
Anticipated expiration: 2016-03-08
Also published as: JPH09242728A; FR2745865A1; GB9604910D0; GB2310904B; FR2745865B1

Description

IMPROVED BLIND RIVET This invention relates to a rivet, and in particular to a blind rivet nut.

Rivet nuts are used to provide a threaded mounting in a sheet material. Known rivet nuts comprise a body having a bore with an internal thread and a flange at one end. A threaded member is placed within the nut. The nut is then placed into a hole in a sheet such that the flange abuts the sheet. The threaded member is then rotated so as to place the tubular body in compression.

A portion of the tubular body deforms securing the sheet between the flange and the deformed portion of the tubular body. A portion of the internal thread is not deformed and the threaded member may now be rotated in an opposite fashion to remove it from the deformed rivet nut.

The portion of the internal thread not deformed can then be used as a mounting point to secure other sheet bodies by use of threaded members having an appropriate thread. An example of such a rivet nut can be seen in EP 0 531 634A.

Such rivet nuts suffer from the disadvantage that they can only be set once at the blind side of the sheet to secure the rivet nut to the sheet.

In various industries there is a requirement for a fixing that can be set reliably at more than a single location.

There is also, for example, in automotive manufacture, during assembly of two sheet metal components in accurate alignment, a requirement for a spigot dowel for location and alignment. Once this operation is completed, the sheets are often fastened together to complete the assembly using a separate fixing. Further components may then be added to the assembly. It would be an advantage if the alignment and securing requirements could be performed by a single fixing.

According to a first aspect, the present invention provides a blind rivet comprising a shank, the shank having a flange at one end and a bore extending from the flange into the shank, at least a part of the bore remote from the flange having a thread, characterised in that in a first portion of the shank adjacent the flange the bore has a larger diameter, in a second portion of the shank the bore an intermediate diameter, and in a third portion of the shank remote from the flange the bore has a smaller diameter.

Preferably adjacent portions of the bore are separated by shoulders.

According to a second aspect of the invention a method of setting a rivet according to the first aspect is provided comprising the steps of a) inserting the rivet through a hole in a first body; b) deforming the first portion of the shank to secure the first body between the first portion and the flange; c) adding a second sheet body by way of a hole in the second sheet body d) deforming the second portion of the shank to secure the second body between the first portion and the second portion Preferably a third body may be secured by means of a threaded member having a head passing through a hole in the third body and secured to the thread of the rivet, thereby securing the third body between the head of the threaded member and the flange of the rivet.

The invention will now be described, by way of example only, in the accompanying drawings in which Figure 1 shows a rivet nut according to the first aspect of the invention; Figure 2 shows the rivet nut located on an end of a setting tool; Figure 3 shows the rivet nut secured against a first sheet body; Figure 4 shows an end of a setting tool in the rivet nut of Figure 3; Figure 5 shows the rivet nut of Figure 3 secured against a second sheet body; Figure 6 shows a threaded member used to secure a third sheet body to the assembly of Figure 5; and Figure 7 shows the rivet nut of Figure 1 with a rounded tip.

In Figure 1 there is shown a rivet nut comprising a body having a shank 2 of substantially constant outer diameter, a flange 3 at one end of the shank and a bore 4 extending from the flange into the shank. The shank 2 comprises three principal portions; a first portion 5 having a large diameter bore; a second portion 6 of intermediate diameter bore; and a third portion 7 of smaller diameter bore.

Shoulders 8, 9 separate each of the adjacent portions.

The bore of the third portion is provided with a thread 10 over at least a part of its length.

In use an underside of the flange 3 abuts one surface of a first sheet body 12 against which the rivet nut is to be set.

A known rivet nut setting tool can be used to set the rivet. As shown in Figure 2, a pulling rod 14 having a threaded member 15 may be rotated into the rivet nut, the threaded member 15 engaging the threaded 10 such that a tool nose piece 13 abuts the flange 3.

With the underside of the flange 3 abutting the first sheet body 12 and the shank 2 of the rivet nut 1 extending through a hole 16 in the first sheet body, the pulling member is withdrawn into the tool nosepiece, placing the shank into compression.

The wall thickness being least at the first portion 5, this buckles or collapses to form a first bulge 11. The sheet body 12 is thus secured between the flange 3 and the first bulge 11.

A second tool, or indeed the first tool with a different nosepiece, may be used to create a second bulge 19. The tool comprises a pulling rod 14' having a threaded member 15' extending from within a nosepiece 18. This nosepiece 18 is cylindrical and in use extends into the bore 4 until it abuts the shoulder 8 between the first and second portions 5, 6 of the bore. The threaded member 15 is rotated into the third portion for engagement with the thread 10.

A second sheet 20 is located over the shank 2 by way of a hole 21 in the second sheet 20. The shank of the rivet at an end remote from the flange 3 is provided with a bevelled end 27, which may be used to aid location of the second sheet 20 over the rivet shank 2. In this way the rivet acts as a dowel or spigot to support and temporarily locate the second sheet 20.

On actuating the tool the pulling rod 14 is withdrawn once again placing the rivet nut in compression. The undeformed part of the first portion 5 of the shank is now supported by the tool nosepiece 18, and so the second portion 6 of the shank will be the first to deform to form a second bulge 19.

In Figure 5, the second sheet body 20 can be seen secured between the first and second bulges.

Figure 6 shows a third sheet member 22 secured to the assembly of the first and second sheet members by way of a threaded fastener 23. The fastener comprises a head 24 and a threaded shank 25. The shank passes through a hole 26 in the further sheet member and engages the thread 10 of the third portion of the rivet.

The fastener may then be tightened to secure the further sheet member 22 between the head 24 of the fastener and the flange 3 of the rivet.

To aid further in the location of the second sheet body the rivet nut may be provided with a tapering conical end 26 (Figure 6) rather than the bevelled end 27 (Figures 1 to 5).

Claims

1 A blind rivet comprising a shank, the shank having a flange at one end and a bore extending from the flange into the shank, at least a part of the bore remote from the flange having a thread, characterised in that in a first portion of the shank adjacent the flange the bore has a larger diameter, in a second portion of the shank the box has an intermediate diameter and in a third portion of the shank remote from the flange the bore has a smaller diameter.

2 A rivet according to claim 1, characterised in that adjacent parts of the bore are separated by shoulders.

3 A rivet according to claim 1 or claim 2, characterised in that an end of the rivet remote from the flange has a tapered or frusto-conical form.

4 A method of securing a first body and a second body by usage of a rivet according to any previous claim, characterised by the steps of: a) inserting the rivet through a hole in the first body; b) deforming the first portion of the shank to secure the first body between the first portion and the flange; c) passing the second body over the rivet shank through a hole in the second body; d) deforming the second portion of the shank to secure the second body between the first portion and the second portion.

5 A method of securing the first body, the second body and a third body together comprising the steps of claim 4, characterised by the steps of: e) aligning a hole in the third body with the bore in the rivet; and f) passing a threaded member having a head through the hole in the third body, into the bore to engage the threaded member with the thread and secure the third body between the head and the flange.

6 A blind rivet substantially as described herein with reference to and as illustrated in the accompanying drawings.

7 A method of securing bodies together substantially as described herein with reference to and as illustrated in the accompanying drawings.