GB2281948A

GB2281948A - Tool-engaging formations on bolts

Info

Publication number: GB2281948A
Application number: GB9418407A
Authority: GB
Inventors: Ambrose Dowling
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-09-15
Filing date: 1994-09-13
Publication date: 1995-03-22
Anticipated expiration: 2014-09-13
Also published as: GB9418407D0; GB2281948B

Abstract

A bolt 1 is provided in its shank portion 3 with a formation (e.g. hexagonal recess 5) engageable by a tool (not shown) to ensure relative turning between the bolt 1 and a nut (not shown) engaged on the shank portion 3. The formation may be a slot or cruciform recess in the bolt tip, or the bolt tip may be polygonal or oval in cross-section, or the formation may be a transverse blind or through-hole in the shank portion 3. The recess 5 may extend the whole length of the bolt 1. <IMAGE>

Description

Title: A SCREW-THREADED BOLT This invention relates to removable fasteners and in particular to screw-threaded bolts.

During engagement or release of a nut and bolt type fastener it is generally necessary to hold the head of the bolt, with a spanner for example, while the nut is tightened or released on the bolt. This can be excessively labour-intensive in such procedures as industrial roof cladding, where one operator on the roof has to coordinate his activity with another beneath the roof. In some cases these fasteners may be mounted on machinery in positions where access to the bolt head is severely restricted and it may be difficult or impossible to fit a spanner on the bolt head. Fastening or releasing the nut is therefore generally awkward and time consuming and may result in damage to the nut and/or bolt. Moreover a bolt head may be round (cylindrical) or dome-shaped and thus resistant to manipulation.

The present invention is directed towards overcoming some or all of these problems.

According to the invention there is provided a bolt which comprises a screw threaded shank, a bolt head at one end of the shank and engagement means, other than the lateral flats of the bolt head, for a tool effective to immobilise the bolt while a cooperating nut is turned, or to turn the bolt while said nut is held immobile, the engagement means being such as not to impede the application of a nut to or its removal from the threaded shank.

The engagement means is preferably located at the end of the shank remote from the bolt head. It may be, for example, an open-ended slot. It may be a transverse blind or through bore into which a rod can be inserted as the tool. It may be a tip or spigot end on the shank, having a reduced and polygonal cross-section such as a square or a hexagon, adapted for arrest or actuation by means of a spanner. For preference, however, the engagement means is a socket, coaxially sunk into the end surface of the bolt shank, and desirably having a polygonal, especially a hexagonal shape in cross-section. In the latter case, the tool may be a conventional L-shaped hexagonal key such as an Allen key.

In a special case of the coaxial socket, said socket comprises a hollow core that extends through a substantial part of the length of the bolt. This bolt may be cut to a desired length, and will still present a socket at its tip, accessible to a suitable key. As a further refinement, the socket may extend for the full length of the bolt including the bolt head, so as to present at each end of the bolt a respective opening accessible to said key. This bolt can be turned or immobilized at its head end despite having a cylindrical or dome-shaped head.

The invention will be more clearly understood from the following description of a preferred embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which; Fig 1 is a perspective view of a bolt according to the invention, Fig 2 is a plan view of the bolt, and Fig 3 is a side view of the bolt, in use.

Referring to the drawings there is illustrated a bolt according to the invention indicated generally by the reference numeral 1. The bolt 1 has a conventional hexagonal head 2 and a threaded shank 3 with a free end 4. A socket 5 having a hexagonal shape in crosssection is provided at the free end 4 of the bolt 1.

The socket 5 is coaxial with the shank 3.

Fig. 3 shows the bolt 1 in use together with a complementary nut 8, clamping together a pair of metal plates 10 and 11. A spanner 12 is used to tighten the nut 8 on the bolt 1 and an Allen key 13 is engaged with the socket 5 and held, to prevent rotation of the bolt 1 as the nut 8 is tightened on the bolt 1 against the plate 10.

It will be appreciated that the bolt 1 can be engaged with or disengaged from the nut 8 without any need to grip the head 2 of the bolt 1 which may be in an inaccessible position or not adapted for gripping, and thus may be difficult or impossible to grip with a spanner. Access to only one side of the plates 10, 11 is required to fasten or release the bolt 1.

It will also be appreciated that the spigot or socket in the free end of the bolt may be of any other suitable profile, for example, square or triangular or oval in cross-section, for engagement by an associated spanner or L-shaped tool. Moreover a cross-shaped socket may be provided, for engagement by a Philipstype screwdriver.

Further instead of a spigot or a socket an open ended slot extending across the free end of the shank may be provided for engagement by a conventional blade-headed screwdriver or the like.

The bolt may be of any suitable material of construction. The invention is not limited to the embodiment hereinbefore described which may be varied in both construction and detail.

Claims

1. A bolt for use as part of a nut-and-bolt type fastener, which bolt comprises a screw-threaded shank and a bolt head at one end of the shank, characterised by engagement means elsewhere in the shank for a tool effective to immobilise the bolt against turning while a cooperating nut is turned, or to turn the bolt while said nut is held immobile against turning, the engagement means being such as not to impede the application of a nut to or its removal from the threaded shank.

2. A bolt according to Claim 1, characterised in that the engagement means is located at the end of the shank remote from the bolt head.

3. A bolt according to Claim 2, characterised in that the engagement means is a socket, coaxially sunk into the end surface of the bolt shank.

4. A bolt according to Claim 3, characterised in that the socket has a polygonal shape in cross section.

5. A bolt according to Claim 4, characterised in that the shape is hexagonal.

6. A bolt according to Claim 3, characterised in that the socket comprises a hollow core that extends through a substantial part of the length of the bolt.

7. A bolt according to Claim 6, characterised in that the hollow core extends for the full length of the bolt including the bolt head.

8. A bolt according to Claim 2, characterised in that the engagement means is an open-ended slot for use with a blade-ended screwdriver.

9. A bolt according to Claim 1, characterised in that the engagement means is a transverse socket in the shank, into which a rod can be inserted as the tool.

10. A bolt according to Claim 2, characterised in that the engagement means is a tip or spigot end on the shank, having a reduced and polygonal crosssection with which a spanner can engage as the tool.

11. A bolt according to Claim 3, characterised in that the engagement means is a cross-shaped socket, adapted for use with a Philips-type screwdriver.

12. A bolt for use as part of a nut-and-bolt type fastener, substantially as herein described with reference to or as illustrated in the accompanying drawings.