GB2239686A

GB2239686A - Bolt with transversely-elongate head

Info

Publication number: GB2239686A
Application number: GB9027811A
Authority: GB
Inventors: Andrew Charles Walden Wright
Original assignee: Dzus Fastener Europe Ltd
Current assignee: Dzus Fastener Europe Ltd
Priority date: 1990-01-03
Filing date: 1990-12-21
Publication date: 1991-07-10
Anticipated expiration: 2010-12-21
Also published as: GB9000070D0; GB9027811D0; GB2239686B

Abstract

A bolt (2) comprises a transversely-elongate head (5) for blind insertion through elongate apertures (13) in a pair of members (14, 15), the bolt (2) carrying a sleeve (3) slidable along the bolt (2) but prevented from rotating on it, the sleeve (3) having dogs (12) which engage in the aperture (13). The sleeve (3) has flats (11) which engage flats (9) on the bolt (2) to prevent relative rotation. The flats (9) may instead extend from the head (5) and be angularly offset from the elongations (6) of the head (5). The apertures (13) may be circular with outward extensions or with inward incursions. Alternatively, the sleeve (3) may be omitted, and the bolt prevented from rotating in the apertures (13) by providing pips on the elongations (6) or forming the bolt with an octagonal section. <IMAGE>

Description

DESCRIPTION A FASTENER The present invention relates to a fastener and, more particularly, to a fastener which is able to draw together a panel and a support in use and whidh requires access from one side only in order to effect fastening.

Many fasteners are known for the purpose of fixing together a pair of members such as a panel and a support, which may, for example, be sections of self-assembly furniture or rack systems, or even rapid assembly buildings (which are usually of a temporary nature). However, prior art fasteners generally require access from both sides of the members and the use of two tools and this is obviously not convenient in all cases. In addition, there is a need for a fastener which, whilst allowing assembly from one side of the junction only, also draws the members together, is easily removable and re-usable, which can be provided as one assembly and which can be used from either side of the junction.

According to a first aspect of the present invention, there is provided a fastener for mounting at apertures in a pair of members which are to be attached, the fastener comprising: a bolt having at one end a head with at least one pawl portion and being threaded along part of its length; a nut in screw-threaded engagement with the bolt; a sleeve slidable on the bolt, between the head and the nut, the sleeve having at least one dog for engaging the edge of the or each aperture through which the head of the bolt is passed in use to mount the fastener; and, means for preventing relative rotation between the bolt and the sleeve.

This fastener provides a positive high clamp load and, in particular by virtue of the dog or dogs on the sleeve, a high sheer load capability.

Preferably there are two pawl portions on the head, diametrically opposite one another, the bolt therefore being generally T-shaped.

The means for preventing relative rotation between the bolt and the sleeve preferably comprises a pair of flats along a portion of the shank of the bolt intermediate the head and the thread, which engage corresponding flats provided within the bore of the sleeve.

The shank of the bolt may have what is hereinafter described as a lozenge-shaped cross-section immediately underneath the head. The sleeve is provided at one end with corresponding cutouts. The lozenge-shaped shank and cut-outs provide rotation stops for the bolt and contribute to providing an indication by feel of the bolt being in its locked position. The lozenge shapes also assist in the prevention of relative rotation between the sleeve and the bolt.

As a further alternative, the means for preventing rotation between the bolt and the sleeve may comprise one or more ribs along the shank of the bolt which engage corresponding recesses in the bore of the sleeve.

According to a second aspect of the present invention, there is provided a fastener for mounting at apertures in a pair of members which are to be attached, the fastener comprising: a bolt threaded along part of its length and having a head provided with a least one pawl portion; and, a nut in screw-threaded engagement with the bolt; the bolt having locking means provided at or towards the head end of the bolt comprising a non-circular cross-section along at least part of its length so as to prevent rotation of the bolt when the fastener is locked in position by tightening of the nut by virtue of the locking means engaging the edges of the or each aperture in use.

The locking means may comprise pips provided on the underside of the pawl portions which engage corresponding cutouts in the or each aperture in the members.

Alternatively, the locking means may comprise a portion of the shank immediately adjacent the head of the bolt having a polygonal cross-section which engages in use the or each aperture which is correspondingly shaped so as to receive that part of the bolt. Preferably the cross-section is regular.

A bar may be provided on the bolt opposite the head end so as to aid alignment of the bolt. The sleeve may be provided with wings so as to enable the fastener to be hand-tightened.

In each aspect of the invention, a visual indication that the bolt is locked may be provided on the bolt and/or the sleeve. This may comprise, for example, ribs which would be, say, vertical when the bolt is in its locked position. Alternatively, a projection or other feature on the bolt/sleeve may align with a feature provided on one of the members when the bolt is locked.

In order to ease removal of the fastener of each aspect of the invention, a shoulder may be provided on the sleeve and/or nut so that the fastener may be levered from the apertures.

Five examples of the present invention will now be described with reference to the accompanying drawings in which: - Figure 1(a) is a cross-sectional view of a first example of a fastener in its unlocked position on panels according to the first aspect of the present invention; Figure l(b) is a cross-sectional view of the first example of the fastener in its locked position on panels; Figure l(c) is a partial cross-sectional view of the sleeve of the first example; Figure l(d) is a plan view of the sleeve shown in Figure 1 (c); Figure l(e) is a plan view corresponding to Figure 1 (a); Figure l(f) is a plan view corresponding to Figure 1 (b);; Figure l(g) is a plan view of a member showing an aperture; Figures 2(a) to (g) are similar views to those in Figure 1 and Figure 2(h) is a plan view of the bolt of a second example of a fastener and its components according to the first aspect of the present invention; Figures 3(a) to (g) are similar views to those in Figure 1 of a third example of a fastener and its components according to the first aspect of the present invention; Figures 4(a) to (g) are various views of a first example of a fastener and its components according to the second aspect of the present invention; and, Figures 5(a) to (g) are various views of a second example of a fastener and its components according to the second aspect of the present invention.

In Figures 1 there is shown a fastener 1 comprising a bolt 2, a sleeve 3 and a nut 4. The bolt 2 has a head 5 which has a pair of diametrically opposite pawl portions 6 which extend laterally, giving the bolt 2 a T-shape. The bolt 2 is threaded at the other end 7 so that the nut 4 may be screwed down along the shank 8 of the bolt 2. The shank 8 of the bolt 2 is provided with flats 9 along the portion intermediate the head 5 and the threaded end 7.

The sleeve 3 has a bore 10 which is provided with flats 11 which engage the flats 9 on the shank 8 so that the bolt 2 can slide within the sleeve 3, but is unable to rotate relative to the sleeve 3. The sleeve 3 has a pair of dogs 12. The sleeve 3 is shown as having a substantially hexagonal shape, which is provided as an aid to positioning of the fastener 1 as it can be gripped by a conventional spanner.

Figure l(g) shows the aperture 13 provided in a pair of members 14,15, each aperture 13 being substantially identical and of what in this specification will be described as "double-D" shape.

In use, the fastener 1 is pre-assembled by sliding the bolt 2 through the sleeve 3 and screwing the nut 4 partially onto the threaded end 7 of the bolt 2 so as to retain the sleeve 3 on the bolt 2. The members 14,15 are brought together with their apertures 13 aligned and the head of the bolt 2 is put through the apertures 13, the pawl portion 6 being able to pass through by virtue of the elongate form and arcuate ends 16 of the double-D apertures 13. The sleeve 3 and bolt 2 are rotated together through 900 so that the pawl portions 6 engage behind part of the support 15 adjacent its aperture 13 and so that the dogs 12 can enter the apertures 13. The nut 4 is then tightened so as to draw the bolt 2 into the sleeve 3 and therefore tighten the members 14,15 together.

The provision of the dogs 12 which pass through both the members 14,15 allows the fastener 1 to withstand high shear loads in all directions and also prevent rotation of the sleeve 3, which in turn prevents rotation of the bolt 2 during tightening of the nut 4.

Figures 2 show a modified version of the fastener 1 shown in Figures 1 and the same reference numerals are used for corresponding components. In this example, the flats 9 extend partially along the shank 8 from the head 5 and are offset relative to the pawl portions 6 so as to give that part of the shank 8 a lozenge-shaped cross-section.

This is shown particularly clearly in the view shown in Figure 2(h) which is a view from the threaded end 7 of the bolt 2 towards its head 5. These flats 9 are received by corresponding flats 11 in the bore 10 of the sleeve 3.

In use, the fastener is installed in the same way as the example shown in Figures 1 and further description thereof is not necessary. However, it is noted that by virtue of the flats 9 extending through the apertures 13 in use, the apertures 13 are kept in alignment at all times when the head 5 projects through the apertures 13 and this greatly eases fastener release. The lozenge-shaped part of the shank 8 engaging the apertures 13 provides a rotation stop by virtue of the flats 9 engaging the straight portions of the apertures, thus preventing further rotation of the bolt 2 and sleeve 3 beyond the locked and unlocked positions. Moreover, small arcuate surfaces 9a between pairs of flats 9, which project through the apertures 13, engage the arcuate parts of the double-D apertures 13.

This improves the shear load carrying ability of the fastener and prevents misalignment of the members during removal of the fastener.

A third example of the first aspect of the present invention is shown in Figures 3. In this example, which corresponds closely to that shown in Figures 1, the apertures 13 are generally circular with rectangular cutouts 17. In use, the pawl portions 6 pass through the cutouts 17 and the sleeve 3 and bolt 2 are rotated together through 900. The nut 4 is then tightened as before. The provision of the generally circular aperture 13 corresponding to the circular shank 8 of the bolt 2 keeps the members 14,15 and fastener 1 in constant alignment, thus aiding fitting and removal of the fastener 1.

In each of the examples shown in Figures 1 to 3, a visual indication of when the fastener is in its locked position may be provided on the bolt 2 and/or sleeve 3 for observation from either end and at any angle.

Two examples of the second aspect of the present invention are shown in Figures 4 and 5. A fastener 1 has a bolt 42 which is threadably received in a nut 43. The nut 43 is provided with wings 44 to aid fitting and removal of the fastener 41.

The bolt 42 has a head 45 provided with pawl portions 46 each of which, in the example shown in Figures 4, has a pip 47 on its undersurface.

The shank 48 of the bolt 42 is threaded along its length and is provided at the end opposite the head 45 with a small aperture 49 through which a bar 50 is passed after the bolt 42 has been slid and screwed through the bore 51 of the nut 43 for rotation of the bolt 42 in use.

In this example, the members 52, 53 have substantially identical apertures 54 which are generally circular but each of which has a pair of diagonally opposed major recesses 55 and, at right angles thereto, a pair of minor recesses 56.

In use, the head 45 of the bolt 42 is passed through the aperture 54, the pawl portions 46 passing through the major recesses 55. The bolt 42 is then rotated through 900 by use of the bar 50, this bar 50 also providing a visual indication of when the bolt 42 has in fact been rotated through 900. The bolt 42 may then be withdrawn slightly so as to locate the pip 47 in the minor recesses 56 and the wing nut 43 is then tightened so as to draw together the members 52,53. Thus, a simple fastener is provided which can be installed from one side of a junction without requiring access to the other side.

In Figures 5, a similar fastener is shown, and components corresponding to those shown in Figures 4 are referenced accordingly. This example differs in that the locking means, which in the example shown in Figures 4 comprise the pips 47 which engage the minor recesses 56, in the example shown in Figures 5 comprise an octagonal section 58 of the shank 48 of the bolt 42 which engages a generally octagonal aperture 57, provided with major recesses 55. In use, the head 45 of the bolt 52 is passed through the aperture 57, the pawl portions 46 passing through the major recesses 55, until the whole of the octagonal section 58 is clear of the member 53. The bolt 52 is then rotated through 900 by use of the bar 50 as before, and the bolt 42 may then be withdrawn slightly so as to engage the octagonal section 58 with the octagonal aperture 57. The fastener may then be tightened by turning the winged nut 43 as before.

Claims

1. A fastener for mounting at apertures in a pair of members which are to be attached, the fastener comprising: a bolt having at one end a head with at least one pawl portion and being threaded along part of its length; a nut in screw-threaded engagement with the bolt; a sleeve slidable on the bolt, between the head and the nut, the sleeve having at least one dog for engaging the edge of the or each aperture through which the head of the bolt is passed in use to mount the fastener; and, means for preventing relative rotation between the bolt and the sleeve.

2. A fastener according to claim 1, comprising two diametrically opposite pawl portions on the head.

3. A fastener according to claim 1 or claim 2, wherein the means for preventing relative rotation between the bolt and the sleeve comprises a pair of flats along a portion of the shank of the bolt intermediate the head and the thread, which engage corresponding flats provided within the bore of the sleeve.

4. A fastener according to any of claims 1 to 3, wherein the shank of the bolt has a lozenge-shaped cross-section immediately underneath the head, and wherein the sleeve is correspondingly shaped.

5. A fastener for mounting at apertures in a pair of members which are to be attached, the fastener comprising: a bolt threaded along part of its length and having a head provided with a least one pawl portion; and, a nut in screw-threaded engagement with the bolt; the bolt having locking means provided at or towards the head end of the bolt comprising a non-circular cross-section along at least part of its length so as to prevent rotation of the bolt when the fastener is locked in position by tightening of the nut by virtue of the locking means engaging the edges of the or each aperture in use.

6. A fastener according to claim 5, wherein the locking means comprise a pip on the underside of the or each pawl portion for engaging corresponding cutouts in at least one of the apertures in the members to be attached.

7. A fastener according to claim 5, wherein the locking means comprise a portion of the shank immediately adjacent the head of the bolt having a polygonal cross-section which engages in use the aperture in at least one of the members to be attached which is correspondingly shaped so as to receive that part of the bolt.

8. A fastener, substantially as described with reference to any of Figures 1(a) to l(g), 2(a) to 2(h), 3(a) to 3(g), 4(a) to 4(g), or 5(a) to 5(g), of the accompanying drawings.