IE76324B1 - A screw-threaded bolt - Google Patents

Abstract

This invention provides a bolt for use as part of a nut-and-bolt type fastener, comprising a screw-threaded shank and a bolt head at one end of the shank, wherein engagement means is located elsewhere in the shank, preferably at the free tip thereof remote from the bolt head, for a tool effective to immobilise the bolt against turning with respect to a nut engaged with the screw thread. The engagement means can be and open-ended slot for a bladed screwdriver or a socket adapted to take a Philips-type screwdriver or (for preference) an Allen key. It may be a tip or spigot end for engagement by a spanner, especially a socket spanner. The invention helps in cases where the bolt head is difficult of access or difficult to grasp. In a special variant, the socket extends throughout a substantial part of, or all of, the length of the bolt.

Description

This invention relates to removable fasteners and in particular to screw-threaded bolts.

During engagement or release of a nut and bolt 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.

It is known to provide a bolt which comprises a screw 5 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 known engagement means is often 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.

Frequently, however, the engagement means is a socket, coaxially sunk into the end surface of the bolt shank, and. commonly 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.

According to the invention there is provided a bolt for use as part of a nut-and-bolt fastener, which bolt comprises a screw-threaded shank and a bolt head at one end of the shank, and comprises 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, wherein the engagement means is a socket, coaxially sunk into an end surface of the bolt shank and extnding through a substantial part of the length of the bolt.

This first bolt may be cut to shorten it, 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 second 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. ί.

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 10 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 thus may be difficult or spanner. Access to only is required to fasten or not adapted for gripping, and impossible to grip with a one side of the plates 10, 11 release the bolt 1, It will also be appreciated that the 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 tool. Moreover a cross-shaped socket may be provided, for engagement by a Philips-type screwdriver.

The bolt may be of any suitable material of 25 construction. The invention is not limited to the embodiment hereinbefore described which may be varied in both construction and detail.

Claims (5)

1. A bolt for use as part of a nut-and-bolt fastener, which bolt comprises a screw-threaded shank and a bolt head at one end of the shank, and comprises 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, wherein the engagement means is a socket, coaxially sunk into an end surface of the bolt shank and extending through a substantial part of the length of the bolt.

2. A bolt according to Claim 1 wherein the socket extends for the full length of the bolt including the bolt head.

3. A bolt according to Claim 2 wherein the socket has a polygonal shape in cross-section.

4. A bolt according to Claim 3 wherein the shape is hexagonal.

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