GB2254666A - U-bolt formed from l-bolts - Google Patents

Abstract

A fastener for connecting a member 17 to a box member 18, comprises two L-bolts 10 and 11 interengageable with one another to define a U-bolt. A socket 14 on one L-bolt 11 receives an end of the L-bolt 10 to limit or prevent angular displacement of each L-bolt about its longitudinal axis. Each L-bolt 10, 11 has a threaded end 12 for a nut 16, and has a tapered section 13 engageable with an expansible sleeve 15 to hold the respective L-bolt 10, 11 in place in an aperture 19, 20. <IMAGE>

Description

A FASTENER AND METHOD OF USING SAME This invention relates to a fastener and more particularly to a fastener which can be used to connect one member to another in circumstances in which it is difficult or impossible to obtain access to one side of the intended connection. The invention also relates to a method of using the fastener.

There are many instances where it is not possible to use a nut and a bolt to connect one member to another chiefly because it is difficult or impossible to obtain access to one side of the intended connection.

For example, it is not possible to use a nut and a bolt to fasten one member to a hollow member such as a box section beam. Welding is not always convenient particularly when connecting members together on site.

Self tapping screws and various forms of expandible connectors are known alternatives to welding. However, self tapping screws, if not properly fitted, can pull out. Also, the heads of the screws have been known to shear away. Expandible connectors do not always grip and if they start to turn in a hole it is difficult to tighten the connection.

According to a first aspect of the invention there is provided a fastener for connecting one member to another member, comprising two parts interengageable with one another to define a generally U-shaped bolt having two spaced arms and a transverse part between the two arms, the two parts being interengageable to limit or substantially prevent angular displacement of each arm relative to the other arm about its longitudinal axis, and each arm having a threaded end portion provided with a co-operating nut.

Preferably, each arm has a tapered section intermediate its ends, each tapered section being tapered towards the threaded end portion of its respective arm and being engageable with an expandible or deformable bush or collar to hold the respective part of the fastener in place in an aperture in one of the members to be connected.

Advantageously, each of the two interengageable parts is of generally L-shape and has a first limb for defining one of the arms of the generally U-shaped bolt and a second limb which together with the second limb of the other generally L-shaped part defines the transverse part of the generally U-shaped bolt. In this case, preferably, the free end portion of the second limb of one of the two generally L-shaped parts is in the form of a socket for receiving the free end portion of the second limb of the other of the two generally L-shaped parts.

According to a second aspect of the invention there is provided a method of connecting one member to another member using a fastener according to the first aspect of the invention and having the first of the preferred features mentioned hereinabove, the method comprising the steps of: (a) providing two apertures in each member to be connected together, the apertures being centered at positions which are spaced apart by a distance equal or substantially equal to the distance between the axes of the two arms of an assembled U-shaped bolt, (b) inserting one part of the fastener into one aperture in one member and then inserting an expandible or deformable bush or collar into that aperture, (c) drawing the tapered section of the one part of the fastener into the bush or collar to expand or deform the latter and hold the one part of the fastener captive relative to said one member, (d) inserting the other part of the fastener into the other aperture in said one member, interengaging said other part with said one part of the fastener, and inserting an expandible or deformable bush or collar into said other aperture, (e) drawing the tapered section of the other part of the fastener into its respective bush or collar to expand or deform the latter and hold the other part of the fastener captive relative to said one member, then, (f) placing the other member over the fastener so that the threaded end portions of the two arms of the fastener project through the two apertures of said other member, and then, (g) placing the two nuts on respective threaded end portions of the two arms of the fastener and tightening the nuts to connect the two members together.

According to a third aspect of the invention there is provided a structural assembly incorporating one or more fasteners according to the first aspect of the invention.

The invention will now be more particularly described, by way of example, with reference to the single accompanying drawing which is a sectional view showing two members connected one to the other by a fastener according to the invention.

Referring to the drawing, the fastener shown therein comprises two L-shaped parts 10 and 11 interengageable with one another to define a generally U-shaped bolt having two spaced, parallel arms and a transverse part between the two arms.

The L-shaped parts are typically of mild steel or stainless steel and each part 10, 11 has a first limb 10a, lla, respectively, defining one of the arms of the generally U-shaped bolt and a second limb 10b, 11-b, respectively, which together with the second limb of the other L-shaped part defines the transverse part of the generally U-shaped bolt.

Each first limb 10a, lla has an externally threaded end portion 12 and a tapered section 13 intermediate its ends. The section 13 tapers towards the threaded end portion 12 of its respective arm and is ideally of frusto-conical shape with its narrower end of larger diameter than the maximum diameter of the threaded end portion 12.

The free end portion of the second limb llb of the part 11 is in the form of a socket 14 and this socket 14 receives the free end portion of the second limb 10b of the part 10 to limit or substantially prevent angular displacement of each L-shaped part 10, 11 relative to the other L-shaped part about the longitudinal axis of its first limb 10a, lla, respectively.

The free end portion of the limb 10b of the Lshaped part 10 is a loose fit in the socket 14 to allow for some relative displacement of the two parts 10 and 11 and thereby facilitate assembly of the fastener.

The fastener also comprises two collets 15 which co-operate with the tapered sections 13 and two internally threaded nuts 16 which co-operate with the externally threaded end portions 12.

Each collet 15 comprises a cylindrical sleeve 15a and an annular flange 15b at one end of the sleeve 15a. The sleeve 15a has two diametrically opposed slits (not shown) extending from the free end of the sleeve along part of its length. The internal diameter of the sleeve 15a is greater than the smaller diameter end of the tapered section 13 and smaller than the larger diameter end of the tapered section 13. Thus, as the tapered section 13 is drawn into the sleeve 15a of its respective collet in a manner to be described hereinafter, the sleeve 15a will deform outwards.

The collets 15 could be replaced by other forms of deformable or expandible collars or bushes.

The fastener is intended primarily for connecting one member to another in circumstances in which it is difficult or impossible to obtain access to one side of the intended connection. It could therefore be used to connect an object to a cavity wall or to a panel having one major face concealed. It can also be used to attach a member to an elongate box section beam or other hollow member. In the particular example shown, the fastener is used in a structural assembly to connect one structural member 17 to another structural member in the form of a box section purlin 18.

Two apertures 19 and 20 are drilled or preformed in the purlin 18. These apertures 19 and 20 are centered at positions which are spaced apart by a distance equal or substantially equal to the distance between the axes of the two arms of an assembled Ushaped bolt made up of the two parts 10 and 11, and have diameters which are greater than the maximum crosssectional dimension of the parts 10 and 11.

The part 11 is then inserted, socket 14 foremost, into the aperture 20. One of the collets 15 is then placed over the externally threaded end portion 12 of the part 11 and is located in the aperture 20.

While still holding the externally threaded end portion 12 of the part 11, the tapered section 13 of the part 11 is drawn into the collet 15 either by placing one of the nuts 16 on the threaded end portion 12 and tightening it down until the collet 15 expands to engage the wall of the aperture 20 to hold the part 11 in place, or by using an appropriate tool.

The part 10 is then inserted, limb 10b foremost, into the aperture 19 and the part 10 is then manipulated so as to insert the free end portion of the limb 10b into the socket 14 of the part 11. The other collet 15 is then placed over the externally threaded end portion 12 of the part 10 and the tapered section 13 of the part 10 is drawn into the collet 15 as described previously.

The nuts 16 are if necessary then removed and the structural member 17, having two pre-formed apertures 21 and 22 therein, is then placed over the threaded end portions 12 of the parts 10 and 11. The nuts 16 are then tightened down to make the connections between the structural member 17 and the purlin 18.

The embodiment described above is given by way of example only and various modifications will be apparent to persons skilled in the art without departing from the scope of the invention as defined by the appended claims. For example, one part 10, 11 may be Lshaped and the other may have a single limb provided with a transverse hole at its innermost end for receiving the free end of the non-threaded limb of the one part.

Claims (8)

1. A fastener for connecting one member to another member, comprising two parts interengageable with one another to define a generally U-shaped bolt having two spaced arms and a transverse part between the two arms, the two parts being interengageable to limit or substantially prevent angular displacement of each arm relative to the other arm about its longitudinal axis, and each arm having a threaded end portion provided with a co-operating nut.

2. A fastener as claimed in claim 1, wherein each arm has a tapered section intermediate its ends, each tapered section being tapered towards the threaded end portion of its respective arm and being engageable with an expandible or deformable bush or collar to hold the respective part of the fastener in place in an aperture in one of the members to be connected.

3. A fastener as claimed in claim 1 or claim 2, wherein each of the two interengageable parts is of generally L-shape and has a first limb for defining one of the arms of the generally U-shaped bolt and a second limb which together with the second limb of the other generally L-shaped part defines the transverse part of the generally U-shaped bolt.

4. A fastener as claimed in claim 3, wherein the free end portion of the second limb of one of the two generally L-shaped parts is in the form of a socket for receiving the free end portion of the second limb of the other of the two generally L-shaped parts.

5. A fastener substantially as hereinbefore described with reference to the accompanying drawings.

6. A method of connecting one member to another member using a fastener as claimed in claim 2, or claim 3 or claim 4 when dependent on claim 2, the method comprising the steps of: (a) providing two apertures in each member to be connected together, the apertures being centered at positions which are spaced apart by a distance equal or substantially equal to the distance between the axes of the two arms of an assembled U-shaped bolt, (b) inserting one part of the fastener into one aperture in one member and then inserting an expandible or deformable bush or collar into that aperture, (c) drawing the tapered section of the one part of the fastener into the bush or collar to expand or deform the latter and hold the one part of the fastener captive relative to said one member, (d) inserting the other part of the fastener into the other aperture in said one member, interengaging said other part with said one part of the fastener, and inserting an expandible or deformable bush or collar into said other aperture, (e) drawing the tapered section of the other part of the fastener into its respective bush or collar to expand or deform the latter and hold the other part of the fastener captive relative to said one member, then, (f) placing the other member over the fastener so that the threaded end portions of the two arms of the fastener project through the two apertures of said other member, and then, (g) placing the two nuts on respective threaded end portions of the two arms of the fastener and tightening the nuts to connect the two members together.

7. A method of connecting one member to another member, substantially as hereinbefore described with reference to the accompanying drawings.

8. A structural assembly incorporating one or more fasteners.according to any one of claims 1 to 5.