GB2387802A

GB2387802A - Tool for engaging a nut/bolt including stop means

Info

Publication number: GB2387802A
Application number: GB0209605A
Authority: GB
Inventors: Mark Synnot
Original assignee: M S TECHNICAL Ltd
Current assignee: M S TECHNICAL Ltd
Priority date: 2002-04-26
Filing date: 2002-04-26
Publication date: 2003-10-29
Also published as: GB0209605D0

Abstract

A tool comprises a first portion 12 joined to a second portion 14, the first portion including a jaw means for engaging a nut/bolt of diameter x so that the tool is rotatable with a first nut/bolt about an axis 10. The second portion comprises stop means having a distal end which is spaced less than 3x from the axis. Preferably the second portion comprises a loop portion which may fit over a second nut/bolt spaced from the first, and a conventional spanner may be used on the other side of the first nut/bolt to tighten or loosen it.

Description

-1 A TOOL

The present invention relates to a tool, in particular a type of spanner or wrench. The invention further relates to a method of tightening or loosening a nut and bolt fixing It is well known to use a pair of spanners to loosen or tighten a nut and bolt fixing. It is also common to replace one or both of the spanners with a socket/ratchet. On large fixings, where the force required to fully tighten or to loosen the fixing is high, it is often necessary to use two personnel, one to hold each of the spanners. The use of two personnel, is clearly inefficient and also may be the cause of injury to the personnel where non- synchronous use of the tools leads to unexpected rotation of one of the spanners causing crushing/slippage injuries to one of the personnel.

It is known to leave the second spanner unmanned and to allow it to rotate until it is wedged against a stop through rotation of the other spanner.

This technique is not ideal as it is often difficult to locate the unmanned spanner without it continually falling off the fixing and/or failing to find a stop to wedge against. Thus, the use of this technique is frequently even less efficient than the use of two personnel.

The present invention seeks to provide a method for a tool which allows the use of a single personnel to loosen or tighten nut/bolt fixings.

According to a first aspect of the present invention there is provided a tool comprising a first portion jointed to a second portion, the first portion comprising jaw means for fixedly engaging a nut/bolt of diameter x so that the tool is rotatable therewith about an axis, and the second portion comprising stop means having a distal end which is spaced less than 3x from said axis.

The present invention thus provides a tool which has a spanner end fixed to a

-2 short stop means. The short length of the stop means allows it to fit and find a stop in many instances where a traditional spanner is simply too long to find a bracing point. The short length of stop leaves the tool providing little mechanical advantage when used as a simple spanner as the lever length is so short, but provides that the tool is far more suitable for the locking required in the instance where the other of the pair of spanners requires the mechanical advantage. Preferably the second portion extends generally away from the axis and curves about the axis in the region of said distal end. The curving of the second portion allows the tool more engagement with the second fixing and reduces the likelihood of the tool falling from the installation before pressure is applied to the other spanner.

According to a second aspect of the invention, there is provided a tool comprising a first portion joined to a second portion, the first portion comprising jaw means for fixedly engaging a nut/bolt of diameter X so that the tool is rotatable therewith about an axis, and the second portion comprising a loop substantially transverse to said axis with curved side portions, each side portion having a focus and both foci being located on an arc centred on the axis, wherein an angle is subtended by lines joining each focus to the axis where B>30 . This is ideal for locating on a known stop and may be fitted at any orientation thereof.

Advantageously, this second portion comprises a loop substantially transverse to said axis, the inner surface of which delimits an opening, wherein in the opening is sized so that a nut/bolt of diameter x is freely rotatable therein.

In this way the second portion can be hooked on to the stop on which it will brace and greatly reduce the likelihood of the tool falling from the nut/bolt fixing. A complete loop is preferred as this greatly reduces the chance that high rotational forces will cause the second portion to flex which could cause injury

-3 to the personnel operating the spanner or indeed cause the tool to simply fall from the fixing.

Preferably, the loop has two generally semi-circular side portions, where the diameter of each semi-circle is of at least x. Each semi-circle has a focus and normally both foci are located on an arc centred on the axis. The tool then allows some angular movement before preventing further rotation of the fixing.

Each focus is normally spaced between 5x/3 to 7x/3 from the axis, which allows a tool of compact size. It is particularly preferred where each focus is spaced 63.2mm from the axis as this is the set distance between fixings on personnel manways in many industries. Thus, the tool can be used to undo or tighten one nut and bolt fixing while using an adjacent fixing as the bracing point. Advantageously an angle is subtended by the lines joining each focus to the axis where is greater than or equal to 30 . Clearly this arrangement allows only limited rotation of the tool about the fixing until it is stopped against the second fixing. Where the second fixing is a further nut/bolt with standard hexagonal shaped crosssections, the 30 angle allows the tool to fit over adjacent fixing whatever the relative positions of the two nuts/bolt heads.

It is preferred for the first portion to be a ring, the inner surface of which is shaped to fixedly engage said nut/bolt. A conventional ring spanner design can thus be used which provides more stable entrainment of the tool on said fixing than an open-ended design.

Normally the tool will be made from iron, steel, magnesium, titanium, chrome, vanadium or alloys thereof.

According to a second aspect of the invention there is provided a method of rotating a first nut and bolt fixing where another fixing is located a preset

-4 distance from the said fixing, the method comprising the steps: a) locating a tool on one of the nut or the bolt head of said first fixing and locating a spanner on the other of the nut or bolt head of said first fixing; b) rotating the spanner to tighten or loosen said fixing where the tool is free to rotate for a maximum of 60 C and then is prevented from further rotating by a second portion of the tool engaging upon said another fixing where the length of the tool is less than four times the diameter of the nut or bolt head of said first fixing. Normally this method will utilise the tool of the first aspect of the invention. It will be appreciated that this method of undoing a fixing helps the personnel which tends to be used in these instances and also greatly lessens the chance of injury to personnel when undoing or doing up the fixing.

The method is particularly useful when said first fixing is substantially the same as said another fixing andfor when said first fixing is a preset distance from said another fixing. In these instances the tool is specifically designed with these parameters in mind thus allow for precise locating of the tool on the . fixings. The invention will now be described in relation to the accompanying drawings, in which: Figure 1 shows a plan view of a first embodiment of the present invention; Figure 2 shows a plan view of a second embodiment of the present invention; Figure 3 shows a plan view of a third embodiment of the present invention; and Figure 4 shows the third embodiment in use.

Figure 1 shows a first embodiment of the tool of the present invention.

The tool comprises a first portion 12 which is substantially ring shaped in cross

-5 section transverse to an axis 10. The first portion comprises jaw means that are fixedly engageable upon an appropriate size nut or bolt head which will lock against the indentations 13 comprising the inner surface of the ring.

Attached to the first portion is a second portion 14 which extends up to a distal end 16. The second portion 14 extends generally away from the axis 10 towards the distal end 16 but is curved in the region of the distal end.

The first portion 12 is attached to the second portion 14 via shank 18.

The distal end 16 is spaced no more than 3 times the diameter 'x' from the axis 10 where 'x' is the diameter of the inner surface of ring and corresponds to the size of the nut/bolt on which the first portion 12 is designed to fixedly engage.

The short overall length of the tool provides that the tool is useful in many installations where space is confined. For example, if the overall length of the tool was greater, as the fixing was rotated the shank length may impinge upon a surface thus riding away from the fixing and disengaging the fixing before a stop is encountered against which the tool could wedge. The tool of the first embodiment works in one direction i.e. to prevent clockwise or counterclockwise motion. To prevent motion in the reverse direction the tool is simply rotated 180 transverse to the axis. Alternatively, in one embodiment now shown, the second portion could extend straight in line from the first portion and then no reversal would be necessary, but it is preferred to have the second portion curved.

Turning now to Figure 2, like numerals represent the same parts as the first described embodiment. The principal difference between the first and second embodiments is the provision of two curved parts in the second portion providing two distal ends 16. The two curved portions are each in the form of an arc of a circle, where the relevant circle has a centre (focus) at points 22.

A line joining each point 22 with the axis 10 subtends an angle of 30 and this angular displacement is very advantageous. Normally the bolt head/nut on

-6 which the first portion 12 is engaged is hexagonal. The tool is normally designed to engage a corresponding adjacent fixing with the second portion to prevent rotation of the first fixing. It is therefore likely that the second fixing will also have a hexagonal head. The angular displacement 30 or more of the two centres allows the tool to locate regardless of the respective orientations of the two hexagonal fixings. The distance from the centres 22 to the axis 10 will normally be known for a particular type of installation, such as a manway where this distance is normally 63.2mm. In these circumstances the tool is particularly advantageous as the tool can be made precisely for this purpose.

Figure 3 shows a third and a particularly preferred embodiment of the present invention. This is generally similar to the second embodiment and like numerals donate like parts. It will be seen that the angle subtended by the lines joining foci 22 and axis 10 (theta) is greater or equal to 30 . Of course can be slightly greater than 30 although it is not envisaged that it will be more than 10 more than 30 otherwise the tool will become unnecessary cumbersome.

The principle difference between the third embodiment and the second embodiment is that the second portion is now in the form of a complete loop thus joining the two distal ends of the second embodiment. The distal end of the third embodiment is not immediately apparent but may be judged as the area of the second portion 14 furthest from the axis 10. The completion of the loop of the second portion 14 greatly aids the rigidity of the second portion 14.

Thus, under high load the second portion 14 is not inclined to bend/flex which would allow some movement of the nut retained in the first portion 12. This greatly assists the user and reduces the likelihood of injury due to slippage.

Figure 4 shows the embodiment of Figure 3 in dotted outline. The tool is shown relative to two nut/bolt fixings 24, 26. The fixing 24 is retained in the first portion 12. The head of the fixing 26 is contained in the loop of the second portion 14. As will be clear the relative angular displacement of the

head of fixing 24 compared to the head of fixing 26 will in no case prevent the head of fixing 26 being containable within the ring of the second portion 14.

It is shown in Figure 4 that the distance between the axis of the first fixing 24 and the second fixing 26 is precisely 63.2mm which is the precise distance between the centres 22 and the axis 10 of the tool of the third embodiment.

It will also be appreciated that the semi-circular ends of the second portion 14 have a diameter which is the same as or just greater than the diameter of the fixing 26 and this close correlation is preferred as this provides in use for the tool to securely locate on the first and second fixings and not be prone to falling from these fixing before load is applied through the first fixing 24. If the diameter of the semi-circle was less than that of the fixing, the fixing would not abut into the ends and is not preferred. If the diameter of the semi-circles was much greater than that of the head of the fixing 26, the tool would be less securely engaged thereupon and be more prone to falling therefrom especially for example where the second fixing 26 is vertically above the first fixing 24.

It is imagined that the diameter of the semi-circle will not be greater than 1 5% more than the diameter of the head of the fixing 24.

The jaw means of the first portion 1 2 and the stop means of the second portion 14 will normally lie in substantially the same plane where the tool is designated to be used to tighten/loosen similar adjacent fixings. The rest of the tool does not have to lie in this plane, but it is preferred if it does lie in the plane. The tool will normally be made from steel or an alloy thereof and other materials which are commonly used for producing spanners and wrenches. The tool will usually be made as a unitary construction in order to improve overall strength. It will be appreciated that the tool is particularly designed for installation where the load applied to the first fixing is relatively high. The diameter of the first fixing is unlikely to be less than 20mm and normally will be between 28 and 34mm, preferably 30 or 32mm.

-8 Generally the present invention provides a tool, in particular a type of spanner or wrench, for use in tightening or loosening of nut/bolt fixings. The invention further provides a method of using the tool. The tool of the invention is used in conjunction with a normal spanner, wrench or ratchet which turns one head of the fixing whilst a first portion of the tool of the invention is located on the second head of the fixing. A second portion of the tool is located against a stop, such as an adjacent fixing, and can thus prevent movement of the second head of the first fixing. The overall length of the tool is short so that the tool can be used in installations where space around the fixing is cramped.

Claims

CLAIMS:

1. A tool comprising a first portion joined to a second portion, the first portion comprising jaw means for fixedly engaging a nut/bolt of diameter x so that the tool is rotatable therewith about an axis, and the second portion comprising stop means having a distal end which is spaced less than 3x from said axis.

2. A tool according to claim 1, wherein the second portion extends generally away from the axis and curves about the axis in the region of said distal end.

3. A tool comprising a first portion joined to a second portion, the first portion comprising jaw means for fixedly engaging a nut/bolt of diameter X so that the tool is rotatable therewith about an axis, and the second portion comprising a loop substantially transverse to said axis with curved side portions, each side portion having a focus and both foci being located on an arc centred on the axis, wherein an angle is subtended by lines joining each focus to the axis where 2 30 .

4. A tool according to claim 1, claim 2 or claim 3, wherein the second portion comprises a loop substantially transverse to said axis, the inner surface of which delimits an opening wherein the opening is sized so that a nut/bolt of diameter x is freely rotatable therein.

5. A tool according to claim 4, wherein the loop has two generally semicircular side portions, where the diameter of each semi-circle is at least x.

6. A tool according to claim 5, wherein each semi-circle has a focus and both foci are located on an arc centred on the axis.

-1 o-

7. A tool according to claim 6, wherein each focus is spaced between 5xt3 to 7x/3 from the axis.

8. A tool according to either claim 6 or claim 7, wherein each focus is spaced 63.2mm from the axis.

9. A tool according to any one of claims 5 to 8, wherein an angle is subtended by the lines joining each focus to the axis, where > 30 .

10. A tool according to any one of the preceding claims, wherein the first portion is a loop, the inner surface of which is shaped to fit said nut/bolt.

11. A tool according to any one of the preceding claims, wherein the tool is made from iron, steel, magnesium, titanium, chrome, vanadium, or alloys thereof.

12. A method of rotating a first nut and bolt fixing where another fixing is located a preset distance from the said fixing, the method comprising the steps: a) locating a tool on one of the nut or the bolt head of said first fixing and locating a spanner on the other of the nut or bolt head of said first fixing; b) rotating the spanner to tighten or loosen said first fixing where the tool is free to rotate for a maximum of 60 C and then is prevented from further rotating by a second portion of the tool engaging upon said another fixing where the length of the tool is less than four times the diameter of the nut or bolt head of said first fixing.

13. A method according to claim 12, wherein the tool comprises the tool of any one of claims 1 to 11.

14. A method according to claim 12 or claim 13, wherein said first fixing is substantially the same as said another fixing.

15. A method according to any one of claim 12 to 14, wherein said first fixing is a preset distance from said another fixing.

16. A tool as hereinbefore described with reference to, and/or as illustrated by the accompanying drawings.

17. A method as hereinbefore described with reference to, and/or as illustrated by the accompanying drawings.