GB2068072A

GB2068072A - Fastener

Info

Publication number: GB2068072A
Application number: GB8102038A
Authority: GB
Original assignee: Adbar Patent Co Ltd
Current assignee: Adbar Patent Co Ltd
Priority date: 1980-01-26
Filing date: 1981-01-23
Publication date: 1981-08-05

Abstract

A fastener or anchor member primilarly for receiving a screw and mainly for use in sheet metal consists of a body (1) having a bore (10) and having at a co-axial tubular end (111) an annular taper portion (12) which has a thin section connection (13) at its smaller end with the body (1) such that the larger end (120) is remote from the body (1). On the taper portion (12) being located in a hole (20) in sheet metal (2) and on the body (1) and taper portion (12) being subject to relative axial force or impact, the thin section connection (13) breaks and the tubular end (111) is expanded over the taper portion (12) and enters (at 112) between the latter and the wall (21) of the hole (20) to tightly secure the fastener in the hole. Some outward bulging (100) of the taper portion (12) may take place on installation to resist pull out. The bore (10) may be plain or threaded to receive a screw. <IMAGE>

Description

SPECIFICATION Fastener The object of this invention is to provide a fastener or anchor member primarily for use in sheet metal or other similar and suitable sheet material whereby effective installation can be readily obtained, e.g. of an internally threaded fastenerfor receiving a screw.

Practical advantages of the invention will be apparent from the following disclosure.

According to the invention the fastener is characterised by a body member having a bore therein and having at a co-axial tubular end thereof an annular taper portion or extension having a thin section connection at its smaller end with the body member whereby the larger end of the taper portion is remote from the body member, the arrangement being such that on the taper portion being located in a hole therefor in parent material such as sheet metal and the body member and taper portion are subject to relative axial force or impact, the thin section connection is broken and the adjacenttubu- lar end of the body member is expanded by the taper portion on their relative axial movement and is caused to enter between the taper portion and wall of the hole in order to tightly secure the fastener in the hole, the tubular end and annular taper portion permitting passage for a screw, pin or the like into engagement with the bore of the body member.

The invention is further characterised by the overall diameter or cross sectional size of the larger end of the taper portion being substantially the same as that of the body member, i.e. prior to installation.

The accompanying drawings show a typical form of the fastener on an enlaryed scale for clarity and in which Figure 1 is an axial plane section of the fastener in its initial condition prior to installation, and Figure2 is an axial plane section showing the fastener fully installed in a hole in sheet metal.

As a fastener in the nature of an anchor nut for use in sheet metal and for receiving a screw, it comprises a tubular body 1 having a threaded bore 10, one end of the body 1 having an outwardly inclined taper portion or extension 12 secured at its smaller diameter end by a thin section connection 13 to the adjacent end of the body 1 so as to leave a shoulder 14.

For convenience in use the larger diameter end 120 of the taper portion 12 is the same or substantially the same as that of the body 1, whilst the open ended bore of the latter is shown extending from end to end of the fastener and includes a plain part 11 extending through the taper portion 12 and co-axial with the threaded part 10. The plain part 11 is of an internal diameter to receive a screw with clearance for screwing into the threaded part 10.

In use the taper portion 12 of the fastener is positioned by its widest diameter end part in a hole 20 in sheet metal 2.

Thus the fastener may be simply placed with the taper portion 12 end first in the hole 20 against an abutment member or plate 3 or, in the case of the same diameter of the body 1 as referred to above, the fastener can be inserted body first through the hole 20 until the wide end part 120 of the taper portion 12 is located in the hole 20. This latter mode of insertion particularly applies to in situ installation of the fastener as referred to below.

With the fastener located in position in relation to the hole 20 in the above manner and on the taper portion 12 and body 1 being subject to relative axial force such as by the application of an axial force or impact to the other end 110 of the body 1, the thin section connection 13 is first broken and the adjacent tubular end 111 of the body 1 is thrust axially over the taper portion 12 and is expanded thereby. As a result of such expansion the material thickness of the end part 111 of the body 1 is reduced at 112 by such expansion and is able to enter the clearance between the wall 21 of the hole 20 and the inclined wall of the taper portion 12. This results in the taper portion 12 and body member 1 being tightly secured in the hole 20 by a force fit or jamming action and practical tests have established that firm attachment can be obtained in this way of considerable strength.

As shown in Figure 2 a further result invariably obtained is outward bulging 100 of the exterior wall of the body 1 immediately adjacent the thinned end part 112 which has entered the hole 20. This is advantageous in providing an abutment to resist pull out where, as is usual, a screw is driven into the fastener from the other or outer side 22 of the sheet metal 2.

In the case of in situ installation of the fastener, i.e.

from one side only of the sheet 2, the abutment 3 may be provided by the forward fixed end of an installation tool (not shown) having a shank or the like which enters the fastener to apply compressive axial pressure on the body 1, e.g. by screw action of the tool shank in the internal threaded bore 10. For this purpose the wide end 120 of the taper portion 12 may have a force fit in the hole 20 to resist rotation during installation.

In the example shown the fastener also has the advantage that the larger diameter end 120 of the taper portion 12 can remain flush with the other or outer side of the sheet metal 2 although, if desired, the said end 120 of the taper portion 12 may have a flange or head (not shown) for location against the outer face of the sheet metal 2.

In addition to its simple form it will be appreciated that the fastener can be readily and rapidly installed under various conditions of use.

The included angle of the taper portion or extension 12 may be of the order of 38 whilst dependent on the size of the fastener the thin section connection may be .015" (0.4mm) and the end shoulder 14 may be of slightly recessed form having an inward inclination of the order of 3 . However these figures are given by way of practical example only and may be varied according to requirements.

Whereas it is convenient in practice for the fastener to be of round section, it may be of square, hexagonal or other cross sectional shape and may be provided with a screwdriver slot or Allen key or similar recess at one or both ends.

It will also be noted that the hole 20 in the sheet metal 2 can be of plain through form, i.e. counter sinking or other formation is not necessary.

If desired the bore 10 of the body member 1 may be plain for receiving a pin or spindle in locating engagement therein.

Claims

1. A fastener or anchor member characterised by a body member having a bore therein and having at a co-axial tubular end thereof an annular taper portion or extension having a thin section connection at its smaller end with the body member whereby the larger end of the taper portion is remote from the body member, the arrangement being such that on the taper portion being located in a hole therefor in parent material such as sheet metal and the body member and taper portion are subject to relative axial force or impact, the thin section connection is broken and the adjacent tubular end of the body member is expanded by the taper portion on their relative axial movement and is caused to enter between the taper portion and wall of the hole in order to tightly secure the fastener in the hole, the tubular end and annular taper portion permitting passage for a screw, pin or the like into engagement with the bore of the body member.

2. A fastener or anchor member according to claim 1 wherein the bore of the body member is threaded to receive a screw in engagement therewith inserted through said annular taper portion and the tubular end of the body member.

3. A fastener or anchor member according to claim 1 or 2 wherein the overall diameter or cross sectional size of the larger end of the taper portion is substantially the same as that of the body member i.e. prior to installation.

4. A fastener or anchor member according to claim 1,2 or 3 wherein the tubular end of the body member after said expansion and on the application of appropriate relative axial force is adapted to bulge outwardly against the back of parent material such as sheet metal adjacent the receiving hole therein in order to resist pull out of the fastener or anchor member from the hole e.g. on tightening a screw in the body member.

5. A fastener or anchor member substantially as herein described with reference to the accompanying drawings.