GB2421554A

GB2421554A - Blind fastener device

Info

Publication number: GB2421554A
Application number: GB0428222A
Authority: GB
Inventors: Simon Klippel; Neil Gill
Original assignee: Tyco European Metal Framing Ltd
Current assignee: Tyco European Metal Framing Ltd
Priority date: 2004-12-23
Filing date: 2004-12-23
Publication date: 2006-06-28
Anticipated expiration: 2024-12-23
Also published as: GB2421554B; GB0428222D0

Abstract

A fastener device comprises a threaded fastener (12) having a head for tightening the fastener (12), a nut (14) having a tapered exterior portion, a slotted sleeve (16) having an axially compressible portion, and an annular collar member (18) having an anti-rotation feature grippable by a tool to prevent rotation of the collar (18). The slotted sleeve further comprises an annular ring portion (17) having at least two arms (19) extending therefrom, said arms (19) being separated from one another by respective slots. The portions of the arms (19) distal to the ring portion (17) define an internal tapered seat adapted to receive the tapered portion of the nut (14). The collar (18) and sleeve (16) are fitted between the fastener (21) and the nut (14) such that the tapered portion of the nut (14) is received in the seat and the collar engages the fastener head such that rotation of the bolt (12) relative to the nut (14) in a desired direction causes the nut (14) to advance towards the bolt head through the slotted sleeve (16) and thereby causes the arms (19) to diverge away from the nut (14) and subsequent axial compression of the compressible portion to reduce the overall length of the sleeve (16). The nut (14) and sleeve (16) are further provided with an anti-rotation means therebetween, there being a projection (54) receivable in a slot (38 - see figure 5) in the sleeve (16).

Description

Blind Fastener Device The present invention relates to a blind fastener

device and in particular to an expandable blind fastener device having the ability to exert a clamping force to a structure through which the fastener passes.

Figures 1 to 3 show an expandable blind fastener generally designated 10 of a known type. The fastener comprises a bolt 12, a irusto-conical nut 14, a slotted sleeve 16, a collar 18 and a deformable spacer 20. The bolt 12, nut 14, sleeve 16 and collar 18 are manufactured from steel, while the spacer 20 is manufactured from a compressible plastics material. The collar 18 is provided with one or more formations which, in use, may be gripped by an appropriately configured tool to prevent rotation thereof.

The sleeve 16 comprises a continuous ring portion 17 from which extend a plurality of arms 19 separated by slots. Figure 1 shows the fastener 10 in an initial unexpanded condition. The fastener components are arranged such that the collar 18 rests against the head 22 of the bolt 12 and the sleeve 16 and spacer 20 are provided intermediate the collar 18 and the nut 14 such that the spacer 20 rests against the collar 18 and the nut 14 is partially received in an open end of the sleeve 16. The sleeve 16 is orientated such that the continuous ring portion 17 is adjacent the spacer 20. In this unexpanded condition the fastener 10 may be inserted through aligned apertures 24,26 in a pair of members 28, 30 requiring to be joined together. As can be seen in figures 1 and 2 there is shown a slight gap 29 between the members 28,30 The apertures 24,26 are of a slightly larger diameter than the sleeve 16 and spacer 20 and the fastener 10 is inserted therethrough such that the collar 18 rests against the outermost member 28.

In order to expand the fastener 10 the bolt 12 is rotated by the application of an appropriately configure driver, such as a spanner, to the head 22 thereof while a suitably configured tool is employed to grip the collar 18. Rotation of the bolt 12 causes the nut 14 to advance along the thread thereof in the direction of the bolt head 22. This movement causes the nut 14 to be drawn into the slotted sleeve 16 with the result that the arms 19 are splayed outwardly by the nut as indicated by arrows 32 in figure 2. It will be appreciated that due to the relative size of the nut 14 to the apertures 24, 26 and the splaying of the arms 19 there will approach a point at which further advance of the nut 14 along the bolt 12 is prevented. At this point further rotation of the bolt 12 results in compression of the spacer 20 as indicated in figure 3. Compression of the spacer 20 in this manner results in a clamping force, indicated by arrows 34, being applied to the members 28, 30 by the collar 18 and the nut 14 via the splayed arms 19. The clamping force urges the members 28,30 towards one another and thus closes the gap 29 therebetween.

It will be appreciated the compressed spacer 20 is located with the aperture 24 of the outermost member 28 and thus is spaced from the interface between the members 28,30. While the above described example of a fastener 10 employs a deformable spacer 20 disposed between the collar 18 and the slotted sleeve 16, the required axial compression feature may be provided by the inclusion of an axially compressible portion of the sleeve 16. Such a portion may be defined by the provision of a weakening in the wall of the sleeve 16.

The present invention seeks to improve the efficiency of this type of threaded fastener.

According to the present invention there is provided a fastener device comprising a threaded fastener having a head for tightening the fastener, a nut having a tapered exterior portion, a slotted sleeve having an axially compressible portion, and an annular collar member having an antirotation feature grippable by a tool to prevent rotation of the collar; the slotted sleeve comprising an annular ring portion having at least two arms extending therefrom, said arms being separated from one another by respective slots, wherein the portions of the arms distal to the ring portion define an internal tapered seat adapted to receive the tapered portion of the nut; wherein further the collar, and sleeve are fitted between the fastener and the nut such that the tapered portion of the nut is received in the seat and the collar engages the fastener head such that rotation of the bolt relative to the nut in a desired direction causes the nut to advance towards the bolt head through the slotted sleeve and thereby causes the arms to diverge away from the nut and subsequent axial compression of the compressible portion to reduce the overall length of the sleeve, wherein further the nut and sleeve are provided with an anti-rotation means therebetween.

The anti-rotation means may comprise a projection of one of the nut and sleeve and an appropriately configured recess of the other of the nut and sleeve. The nut may be provided with a projection of the tapered exterior portion thereof receivable in a recess of the sleeve. In such an embodiment the projection may be formed integrally with the body of the nut. Alternatively the projection may comprise a member fitted or otherwise attached to the nut. The recess of the sleeve may comprise a slot or channel provided in the body of one of the arms of the sleeve. Alternatively the recess may be defined by one of the slots present in the sleeve between the arms.

In an alternative embodiment of the anti-rotation means my be defined by a projection of the sleeve which is receivable in a slot of the nut. The projection of the sleeve may comprise a member fitted to the sleeve. Such a member may be fitted to an arm of the sleeve and may, more specifically extend through the arm to project into the interior of the sleeve. Alternatively the projection may be formed by the deformation of a portion of the sleeve such as, for example an edge of one of the arms.

The compressible portion of the sleeve is preferably provided adjacent the annular collar member. The compressible portion of the sleeve may comprise a portion of the sleeve which has a reduced wall thickness. In such an embodiment the reduced wall thickness may be provided by a peripheral recess formed in the wall of the sleeve. In such an embodiment the sleeve may be formed integrally with the collar In an alternative embodiment the compressible portion of the sleeve may be formed by a compressible member incorporated into the sleeve. The compressible member may preferably be provided between the slotted sleeve and the collar. The compressible member is preferably annular and may be formed from a plastics material.

Embodiments of the present invention will now be described with reference to the accompanying drawings in which: Figures 1 to 3 show partial crosssectional views of the configuration and operation of a

prior art threaded fastener device;

Figure 4 shows a perspective view of a nut according to an embodiment of the present invention; Figure 5 shows a perspective view of a fastener sleeve; Figure 6a shows an end view of a sleeve according to an embodiment of the present invention; Figure 6b shows a cross-sectional view of the sleeve of figure 6a indicated by arrows A-A on figure 6a; Figure 7a shows an end view of a nut according to an embodiment of the present invention; Figure 7b shows a side view of the nut of figure 7a; Figure 8a shows an end view of a sleeve according to an embodiment of the present invention; Figure 8b shows a cross-sectional view of the sleeve of figure 8a indicated by arrows A-A on figure 8a; Figure 9a shows an end view of a nut according to an embodiment of the present invention; and Figure 9b shows a side view of the nut of figure 9a.

Referring firstly to figures 4 and 5 there is shown a sleeve 16 of the type described with reference to figures 1 to 3 and a nut 36 according to an embodiment of the present invention. The sleeve 16 is comprised of a continuous ring portion 17 from which extend a plurality of arms 19 separated by slots 38. The inner surfaces 40 of the portions of the arms 19 distal to the ring portion 17 are tapered so as to define a substantially frusto-conical seat 42 within which a complementarily shaped portion of a nut 14 may be received, in use. The sleeve 16 is essentially tubular and may be formed, for example, from a tubular member which is firstly machined at one end to produce the seat 42 and is then acted upon by an appropriately configured cutter to produce the slots 38 and thereby define the arms 19.

The nut 14 comprises a body 44 having an aperture 46 extending therethrough. The surface of the aperture is provided with a thread 48 which is engageable, in use, with an appropriately configures thread of an appropriately configured bolt, The nut body 44 has a tapered fore portion 50 the taper angle of which substantially matches that of the seat 42 of the sleeve 16. The fore portion 50 is provided with a plurality of knurled grooves 52 and a projection 54. The projection 54 has a thickness which less that the width of the slots 38 with the result that the projection 54 may be received in a slot 38.

In use, a fastener having a sleeve 16 and a nut 14 of the type described with reference figures 4 and 5 is assembled such that the fore portion 50 of the nut 14 is received in the seat 42 of the sleeve 16 with the projection 54 located in a slot 38 of the sleeve 16. It will be appreciated that this arrangement prevents the nut 14 from being rotated relative to the sleeve 16 when the bolt is rotated. The thickness of the projection 54 is sufficient to resist either deformation or shearing as the result of any lateral force being applied thereto as a result of the nut 14 attempting to rotate relative to the sleeve 16.

The projection 54 may be formed integrally with the nut body 44, for example during the formation of the knurled grooves 52. Alternatively the projection 54 may be defined by a separate member fitted to the nut body 44. In such an embodiment the nut body 44 may firstly be provided with a channel or slot in the tapered fore portion 50 thereof into which is fitted and secured a projecting member.

The provision of an anti-rotation means between the nut 14 and sleeve 16 is advantageous as it prevents the possibility of any rotation of the nut 14 relative to the sleeve 16 during initial rotation of the bolt 12. Such rotation of the nut 14 relative to the sleeve 16 in prior art type fasteners may occur in instances where, for example, the nut 14 is only loosely fitted to the seat 42 of the sleeve 16 upon initial assembly of the fastener, where material having low friction properties such as oil, grease, wet paint or water has inadvertently found its way between the nut 14 and sleeve 16, or where the components of the fastener have been subjected to a surface coating. Such a coating may, for example comprise a hot dip galvanised coating which may be applied to the components of the fastener to enhance their corrosion resistance. Such a coating typically fouls the threads of the nut 14 and bolt 12 and can result in the nut 14 becoming temporarily rotationally fixed to the bolt 12.

Alternative embodiments of nuts and sleeves configured in accordance with the present invention are shown in figures 6a to 9b. Looking firstly at figures 6a to 7b there is shown a nut 14 and sleeve 16. Features common to the embodiment described with reference to figures 4 and 5 are identified with like reference numerals. The sleeve 16 differs in that it is provided with an inwardly directed projection 56. The projection 56 is situated on the longitudinal centreline one of the arms 19. The projection is situated longitudinally inwardly of the frusto-conical seat 42 in the direction of the ring portion 17 of the sleeve 16. The projection 56 may be constituted by a pin or the like which is inserted through and secured in a hole extending the arm 19. The nut 14 differs in that it is provided with four equidistantly spaced grooves 58 which extend along the tapered fore portion 50. Although not shown the fore portion 50 of the nut 14 between the grooves 58 may be provided with knurled grooves of the type described with reference to the nut 14 of figure 4. It will be understood that upon fitting of the tapered fore portion 50 of the nut 14 to the seat 43 of the sleeve 16 the projection 56 may be received in one of the four grooves 58 to provide the desired anti-rotation properties between the sleeve 16 and the nut 14.

Referring now to figures 8a to 9b there is shown another embodiment of a sleeve 16 and nut 14 according to the present invention. As before, features common to the previously described embodiments are identified with like reference numerals. The nut 14 of figures 9a and 9b corresponds substantially to that shown in figures 7a and 7b in that it is provided with four equidistantly spaced grooves 58. The sleeve 16 of figures 8a and 8b differs from that shown in figures 6a and 6b in that an edge 60 of one of the arms 19 is bent inwardly towards the interior of the sleeve 16. The edge 60 thus defines a projection which is engageable with one of the grooves 58 to provide the desired anti-rotation feature.

Claims

Claims 1. A fastener device comprising a threaded fastener having a head

for tightening the fastener, a nut having a tapered exterior portion, a slotted sleeve having an axially compressible portion, and an annular collar member having an anti-rotation feature grippable by a tool to prevent rotation of the collar; the slotted sleeve comprising an annular ring portion having at least two arms extending therefrom, said arms being separated from one another by respective slots, wherein the portions of the arms distal to the ring portion define an internal tapered seat adapted to receive the tapered portion of the nut; wherein further the collar, and sleeve are fitted between the fastener and the nut such that the tapered portion of the nut is received in the seat and the collar engages the fastener head such that rotation of the bolt relative to the nut in a desired direction causes the nut to advance towards the bolt head through the slotted sleeve and thereby causes the arms to diverge away from the nut and subsequent axial compression of the compressible portion to reduce the overall length of the sleeve, wherein further the nut and sleeve are provided with an anti-rotation means therebetween.
2. A device as claimed in claim I wherein the anti-rotation means comprise a projection of one of the nut and sleeve and an appropriately configured recess of the other of the nut and sleeve.
3. A device as claimed in claim 2 wherein the nut is provided with a projection of the tapered exterior portion thereof which is receivable in a recess of the sleeve.
4. A device as claimed in claim 3 wherein the projection is formed integrally with the body of the nut.
5. A device as claimed in claim 3 wherein the projection comprise a member fitted to the nut.
6. A device as claimed in any of claims 3 to 5 wherein the recess of the sleeve comprises a slot provided in the body of one of the arms of the sleeve.
7. A device as claimed in any of claims 3 to 5 wherein the recess is defined by one of the slots present in the sleeve between the arms.
8. A device as claimed in claim 2 wherein the anti-rotation means is defined by a projection of the sleeve which is receivable in a slot of the nut.
9. A device as claimed in claim 8 wherein the projection of the sleeve comprises a member fitted to an arm of the sleeve.
10. A device as claimed in claim 9 wherein the member extends through the arm to project into the interior of the sleeve.
11. A device as claimed in claim 8 wherein the projection of the sleeve is formed by a deformed portion of the sleeve
12. A device as claimed in claim 11 wherein said deformed portion of the sleeve comprises an edge of one of the arms.
13. A device as claimed in any preceding claim wherein the compressible portion of the sleeve is provided adjacent the annular collar member.
14. A device as claimed in claim 13 wherein the compressible portion of the sleeve comprises a portion of the sleeve which has a reduced wall thickness.
15. A device as claimed in claim 14 wherein the reduced wall thickness is provided by a peripheral recess formed in the wall of the sleeve.
16. A device as claimed in any of claim 14 or claim 1 5 wherein the sleeve is formed integrally with the collar
17. A device as claimed in any of claims I to 13 wherein the compressible portion of the sleeve is formed by a compressible member incorporated into the sleeve.
18. A device as claimed in claim 17 wherein the compressible member is provided between the slotted sleeve and the collar.
19. A device as claimed in claim 17 or claim 18 wherein the compressible member is annular and formed from a plastics material.