GB2402099A

GB2402099A - Bolt head centre marker

Info

Publication number: GB2402099A
Application number: GB0312560A
Authority: GB
Inventors: Richard James Mathias Jones
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-05-31
Filing date: 2003-05-31
Publication date: 2004-12-01
Also published as: GB0312560D0

Abstract

A bolt head centre marker that allows easy and accurate marking of the exact centre of a bolt head 20. The device comprises a length of rod 10 with a marker at one of the ends, the rod being of the correct dimensions to fit into the square drive receptacle of a standard commercially available socket 21, so that when the socket 21 is placed on a bolt head 20 and the rod 10 inserted so that it contacts the bolt head 20, the marker on the rod 10 marks the exact centre of the bolt head. The marker may comprise a sharpened hardened tip to produce a depression in the bolt head 20 when the rod 10 is struck; an ink marker; or an automatic punch mechanism. A flange (31, fig.3) may be provided on an outer tube (30, fig.3) to help position the rod 10 in the socket 21.

Description

Bolt Head Centre Marker This invention relates to a centre marker for a

bolt head or stud or any length of threaded rod.

Sometimes it is required to mark the exact centre of a bolt head. Primarily this is required when a bolt or stud Camelot be removed by conventional means, and a hole is required through the centre of the bolt in order to 'drill out' the bolt, or for the application of a bolt extractor.

An object of this invention is to provide a bolt head centre marker that allows easy and accurate markhig ol the exact centre of a bolt head.

Tile hivention relies on the use of a 'socket', which is a round section piece of metal with a cut out at one end so as to tit exactly onto a bolt head, and a cut out at the other end designed to accept a standard square metal tube. I he square 'drive' tube has standardised dimensions usually of 3/8, 1/2 or 3/4 inch square. Sockets are used to remove or insert, tighten or loosen bolts, machine screws and nuts, usually with a hexagonal section head. The advantage of sockets over other means of driving bolts and nuts is that a compact set of sockets, with a single long driving bar, can be used to work a wide range of bolt head sizes. Moreover, additional, more complex driving bars, such a those incorporating ratchets and/or torque measuring devices, can easily be used, without duplication for each bolt head size. While it is by no means essential, the socket usually is hollow on the inside, with a continuous space between the square section cut-out and the bolt-head cut- out. One purpose of this is to ease the removal of a bolt or ual that has become wedged hito the socket. This continuous space is crucial to the correct working of this invention.

According to the present invention there is provided a bolt head centre marker comprising a short length of rod, with a marker at the centre of one of the ends, the rod being of the correct dimensions to f it hito the square drive receptacle of a standard socket, so that when the socket is placed on a bolt head, and the rod inserted so that it contacts the bolt head, the marker on the rod marks the exact centre of the bolt head.

The marking action of the device can be with a visible mark (eg, an ink impression), or' by striking the rod, with a depression on the bolt head. The invention could incorporate any of the prior art in metal punches and markers' particularly an 'automatic' marker, where a slow push ofthe rod charges a spring which is released suddenly to punch a depression into the metal.

A specific embodiment of the invention will now be described by way of example with reference to the accompanyhg drawing in which: I:igure I shows in perspective the basic bolt head marking tool Figure 2 shows in perspective the bolt head, socket and bolt head marking tool in position Although some sockets use a continuation ofthe square section into the bolt-head cut out, most have the holt-head and square section cut outs joined by a small circular hole. In this case, a modification of the bolt head centre marker will have to be used. In this case, the bolt head centre marker consists of a length of rod having a cross section such that it will fit through the centre hole of most commercially available sockets. 'I'his rod fits within a larger tube with a hole running through it, such that the rod is tree to move inside the larger tube. In use, the larger tube is positioned into the square section cut out of the socket, and the rod inserted such that it contacts the bolt head. The most logical arrangement would be t'or a circular cross section inner rod rumhg in a cylindrical hole in a square section outer tube. The hater rod could incorporate a visible marker such as an ink marker, could incorporate a sharpened hardened tip to produce a depression in the bolt head when struck, or could incorporate a prior art automatic punch mechanism.

If the approach of having a sliding rod within the larger section outer tube is adopted, then the marked position on the bolt head will be made more accurate by incorporating a flange on the square section tube such that it rests on the 'neck' of the socket, and ensures that the bolt head marking tool is he Ihe with the socket axis.

figure 3 shows hi perspective this modification to the bolt head centre marking tool.

The bolt head centrc marking tool can be used to mark the centre of a piece of threaded rod or a threaded stud by threading a nut of the appropriate size onto the piece, and using this to centre the bolt head markhg tool onto the centre of the threaded rod.

Figure 4 shows in perspective this use of the bolt head centre marking tool.

As shown he figure I the bolt head centre marker comprises a length of rod 10 having at one end a marker I 1. 'this is shown he action in figure 2, where 20 is the bolt to be marked, and 21 is the socket used to centre on the bolt. Figure 3 shows an enhancement to the marker, where a larger section tube is used to carry the marking tube in the socket (30), and additionally, where a flange is used to position the bolt head centre marker on the socket (31). Figure 4 shows the bolt head centre marker he use markhg the centre of a stud or length of threaded rod (40), with the use of an appropriate nut(4 1) to locate the socket. 'I'he marker shown he figure 4 does not incorporate the locating flange.

Claims

Claims 1. A bolt head centre marker comprising a short length of rod, with

a marker at the centre of one of the ends' the rod being of the correct dimensions to fit into the square drive receptacle of a standard socket, so that when the socket is placed on a bolt head, and the rod inserted so that it contacts the bolt head, the marker on the square section rod marks the exact centre of the bolt head.

9. A bolt head centre marker as described in claim I where the marker at the centre of one of the ends of the marker rod is a sharpened point, so that an impact on the free end of the rod marks the centre of the bolt head.

3. A bolt head centre marker as described in claim I, where there is a hole through the centre of a tube that is of the correct dimensions to fit into the square drive receptacle of a standard socket' and a further rod fits exactly through the centre of this hole, and this inner rod has a marker at one end and is longer than the square section rod, so that when the socket is placed on a bolt head, and the bolt head centrc marker placed into the square drive receptacle, the marker on the inner rod marks the exact centre of the bolt head.

4. A bolt head centre marker as described in claim 3 where there is also a flange on outer tube, so that when the bolt head centre marker is placed into the square drive receptacle the flange sits on the base of the socket, and the outer tube is forced to be parallel to the socket.

5. A bolt head centre marker as described in any proceeding claim where a mechanism within, the marker rod automatically marks the exact centre ofthe bolt head when the bolt head centre marker is appl led.

F

6. A bolt head centre marker as described in any proceeding claim where the central rod and outer tube are of any cross section, such as square section or circular section, such that there is a suitable l'it into the square section drive receptacle of the socket, and where the marker rods marks the exact centre of the bolt head.

7. A boll head centre marker as claimed in any proceeding claim, which is used to mark the exact centre of a length of threaded rod, such as a stud, by means of attaching a nut to the end of the length of threaded rod and applying the bolt head centre marker to the nut and threaded rod assembly.

X. A bolt head centre marker as claimed in claims 3 and 4, where a drill bit fits through the central hole he the bolt head ccntre marker, such that a pilot hole can be drilled.

7. A bolt head centre marker as claimed in any proceeding claim which is made from metal, plastics material or ceramic, or from a combination of these materials.

X. A bolt head centre marker as herein described and illustrated in the accompanying drawhgs.